MXPA98010568A

MXPA98010568A - Process for the recovery of oil through ro drying

Info

Publication number: MXPA98010568A
Application number: MXPA/A/1998/010568A
Authority: MX
Inventors: Bloor Davies William; Edward Healy John
Original assignee: Cytec Technology Corp
Priority date: 1996-06-21
Filing date: 1998-12-11
Publication date: 1999-09-01

Abstract

A process for the recovery of oil from a process for the recovery of a water-in-oil or water-in-oil microemulsion water-soluble emulsion containing water-soluble vinyl-added polymer process comprising: (a) the condensation of the oil and water generated by the spray-drying process, to obtain oil and condensed water, and (b) the separation of condensed oil from the condensed water, where condensed oil is substantially free of non-gaseous substances that weaken polymerization

Description

PROCESS FOR THE RECOVERY OF OIL BY DRYING BY ROCÍO FIELD OF THE INVENTION This invention relates in general to processes for the spray drying of dispersions, emulsions and microemulsions containing water-soluble or water-swellable polymers, to obtain substantially dry, water-soluble or water-swellable polymer particles, polymeric particle compositions substantially dry, water-soluble or water-swellable and methods for using such polymeric particles in water treatment, mining, papermaking, biotechnology, food processing, soil conditioning, solution thickening applications and recovery of oil or oil.

BACKGROUND OF THE INVENTION The high molecular weight, water soluble, and water swellable polymers produced from monomers such as acrylamide are FEF. 28 »© commercially important materials. These polymers find use as floculadores for mining operations to recover the metallic mineral from suspensions, the treatment of water to eliminate suspended impurities, etc., in agriculture as soil conditioners, and also in the manufacture of paper to help the formation of paper and in oil or oil recovery industries. Water-soluble and water-swellable polymers are generally commercially available in solution, in dry form, dispersion, water-in-oil emulsion and water-in-oil microemulsion. In many cases polymeric emulsions are convenient, but may be limited to low molecular weight polymers and / or at low solids levels due to the problem of handling viscous solutions, high solids and high molecular weight polymers. At very high solids contents and / or at very high molecular weights, the solutions form gels that can be comminuted to form fine polymer gel particles that can be dissolved in water by the end user. Although these comminuted gels typically contain up to about 20% water, they are often referred to as "dry" polymers to distinguish them from other forms of the product. In many cases the dry polymers show prolonged dissolution times and poor handling characteristics, for example, dusting. Although some handling problems can be mitigated by agglomeration, see for example European Patent 'EP 0 277 018 A2; US Patent Nos. 3,279,924; 3,275,449; 4,696,762; 5,171,781; The solutions and gels of the water-soluble and water-swellable polymers may also suffer from the lack of a convenient method for post-reaction or functionalization of the polymer. Still another problem relates to dry polymer blends, particularly when mixing dry polymers having different particle sizes or different particle size distributions. It is well known that dried polymer particles tend to be stratified with handling and storage, with the larger particles tending to settle to the bottom of the container, and the smaller particles that tend to concentrate towards the top. Stratification can be inconvenient because differences in handling characteristics are found, as a function of vessel depth. The problem of stratification can be exacerbated when two different dry polymers are mixed together, because the particle size distributions of the two products are generally not identical. Stratification with storage can affect the operation of the mixed product as the top of the container tends to be enriched in the polymer having the smallest particle size. For obvious reasons, changes in the operation of the product as a function of the storage depth have to be avoided., and it is generally preferred that each polymer be of similar particle size, for example, see European Patent EP 479 616 Al and US Patent No. 5,213,693. However, when the dry polymer is produced by spray drying, changes in production, for example, changes in dryer size, dryer temperature, apparent viscosity of the feed, type of atomizer, etc. they can effect the particle size, and it can be difficult or impossible to achieve a desired particle size while simultaneously maintaining some other parameter of the production, so that the mixtures of the spray-dried polymers can be adversely affected by the stratification. The advent of water-in-oil emulsion and water-in-oil microemulsion forms of water-soluble and water-swellable polymers solved some of these problems, for example, mixtures of water-in-oil emulsions and water-in-oil microemulsions as described in US Patent Applications Nos. 08 / 157,764 and 08 / 157,795, do not tend to be stratified, and will be simultaneously obtained at high sodium contents, high molecular weight and relatively fast dissolution times. In addition, single functionalized polymers can be produced, which can not be practically manufactured by solution polymerization. For example, U.S. Patent Nos. 4,956,399; 4,956,400; 5,037,881; and 5,132,023, teach that functionalization of a water soluble polymer contained in a water-in-oil microemulsion can be carried out to produce high molecular weight loaded polymers with advantageous flocculation operation. The use of microemulsions, as opposed to emulsions, in polymer production provides improved polymeric performance properties, among other benefits. Polyacrylamides hydrolyzed only with high molecular weight are described in US Pat. No. 5,286,906 ,. In US Patent No. 4,767,540, the polyacrylamide functionalized with hydroxamate, of very high molecular weight, is described and the new charged organic polymeric microspheres are described in US Patents Nos. 5,274,055 and 5,167,766. In addition, methods for the esterification of the (meth) acrylic acid polymer, and optionally, hydroxamation of said polymers are described in US Patent Application Serial No. 08 / 626,297. Despite many benefits provided by the emulsion and microemulsion polymers, the transportation costs associated with such materials remain high and the removal or disposal of the oil and emulsifier in the emulsions may impose environmental problems as secondary contamination. In addition, many emulsion and microemulsion polymers tend to exhibit stability problems, for example, damaging changes in polymeric properties and / or performance, as a function of time. Although the applications Nos. Of Series 08 / 157,764 and 08 / 157,795; and U.S. Patent Nos. 4,956,399; 4,956,400; 5,037,881; 5,132,023; 5,274,055; and 5,167,766 mention solvent-free precipitation and depuration as methods for the recovery of dry polymer products from polymeric microemulsions or mixtures containing microemulsions, water-soluble or water-swellable, these methods can produce a dry polymer with handling properties. or undesirable, poor dissolution times, and low bulk density, etc. Practically, precipitation without solvent and purification can be inconvenient and expensive. The water soluble polymers can also be prepared in the form of suspensions or dispersions of polymer spheres or droplets in a non-aqueous liquid, for example oil. It is said that the reverse phase polymerization process, described in US Pat. No. 4,528,321, forms dispersions of water soluble polymers. Water-soluble polymer dispersions, which can be azeotropically dried, are described in US Patent No. 4,628,078.

U.S. Patent No. 4,506,062 discloses a reverse phase suspension polymerization process for the production of water soluble, high molecular weight polymers and also reports that dried polymer spheres can be obtained by azeotropic evaporation, followed by filtration. However, a problem remains as the azeotropic distillation tends to use a lot of energy, and the filtering process can be dangerous or inconvenient. Although dry polymers can be obtained from dispersions, water-in-oil emulsions or water-in-oil microemulsions, which contain polymer with addition of vinyl by methods such as precipitation in a non-solvent, purification, etc., these methods can also be not practical for economic and environmental reasons due to difficulties in the recovery, purification and recycling of the oil. Although oil recovered from an emulsion or suspension polymerization may occasionally be recycled without further purification, as described in US Patent No. 4,212,784 and Japanese Patent No. 50-124979, in other cases, for example S.I.R. H915, additional purification steps are necessary. The level of impurities in the oil is an important consideration, since certain polymerizations, for example, chain growth polymerizations, or the polymerizations used to make very high molecular weight polymers, are especially sensitive to even trace amounts of weakening substances. the polymerization. Particular problems are also encountered where the polymer has been formed from monomers in the presence of the oil, or the oil has been heated or subjected to processing steps, which may have a tendency to deposit impurities in the oil that weaken the polymerization. Spray drying is the transformation of the feed from a fluid to a dry particulate form, by spraying the feed into a hot drying medium, typically a hot gas. Spray drying is widely used to produce a diverse range of products, for example, instant coffee, dehydrated eggs, instant milk, household detergents, pharmaceuticals, pigments, cosmetics, starch, plastics, ceramics, etc. Typical spray drying equipment, drying procedures, etc., are described in detail in known references, for example, "Spray Drying Handbook", by K. Maester, 5a. Ed. Longman Scientific, 1991. Aqueous solutions of water soluble polymers can be spray dried as described in US Pat. Nos. 3,803,111 and 4,892,932. U.S. Patent Nos. 4,847,309 and 4,585,809 describe the processes for the spray drying of emulsions containing acrylic polymer, US Patent No. 4,798,888 discloses a process for spray drying a polysaccharide emulsion, US Patent No. 4,816,558 describes a process for the spray drying of an aqueous dispersion of a synthetic resin, and US Patent No. 4,112,215 discloses a process for spray drying an aqueous dispersion of a copolymer. U.S. Patent No. 5,025,004 discloses a process for spray drying an emulsion of a water insoluble polymer. US Patent No. 4,035,317 teaches water-in-oil emulsions of water-soluble, vinyl-added polymers, which can be spray-dried, under certain conditions, to produce free-flowing, powder-free polymer particles, which dissolve rapidly in water The polyacrylamide powders, acrylamide / acrylic acid copolymer and acrylamide / di-methylaminopropyl methacrylate copolymers are described therein. The size range of the spray-dried products is such that none of them are smaller than approximately 325 mesh (approximately 40 microns), at least about 50% are larger than about 120 mesh (approximately 122 micrometers), and substantially none of the particles are larger than about 20 mesh (approximately 841 micrometers). These particles do not agglomerate when added to water and dissolve much faster than the traditional dry or gel particles of water-soluble polymers. When the spray dried particles are either larger or smaller than this size range, however, they dissolve with difficulty. Although the invention of US Patent No. 4,035,317 was a significant advance in the art, a difficulty remains nonetheless with respect to certain polymers, since the spray drying methods of said Patent produce polymers whose properties are undesirably changed with respect to the form of emulsion or microemulsion. Attempts to spray-dry the Mannich polyacrylamides according to the teachings in the art resulted in polymer powder showing reduced flocculation performance as compared to that of the corresponding polymers used in the microemulsion form. In addition, the viscosities of the solutions of the spray-dried products tended to be significantly lower than desired. Accordingly, there is a need for a method of recovering water-soluble and water-swellable polymers from dispersions, water-in-oil emulsions or water-in-oil microemulsions, to produce water-soluble polymers, which dissolve rapidly, without affecting adversely affects the properties of the polymer. It could also be advantageous to provide mixtures of two or more dry, spray-dried polymers, and methods for the production thereof, wherein 90% or more of the particles in the mixture are each individually comprised of two or more polymers. , so that the stratification effect on the mixture is minimized. There is also a need for an economical method to produce substantially dry polymers having good handling and dissolution properties. It could also be advantageous to provide methods for spray-drying dispersions, water-in-oil emulsions and water-in-oil microemulsions, which eliminate or reduce undesirable product changes and make possible the recycling or reuse of the components. A method has now been discovered for producing substantially water-insoluble, water-soluble, water-swellable vinyl polymers by spray-drying the corresponding polymer dispersion, water-in-oil emulsion or the corresponding water-in-oil microemulsion. Surprisingly, novel, dry polymer products have been obtained whose properties and / or operation are not changed in a harmful manner by the spray drying process. Surprisingly, the substantially dry polymers produced by the methods of the present invention tend to have improved stability relative to the corresponding polymers in dispersion, in water-in-oil emulsion, or in water-in-oil microemulsion.

Advantageous mixtures of two or more dry, spray-dried polymers and methods for the production thereof are also provided, wherein 90% or more of the particles in the mixture are each individually comprised of two or more polymers. Surprisingly, the dissolution and handling characteristics of the spray-dried polymer particles of the present invention are improved by agglomeration. The methods for using the present compositions of agglomerates and polymeric particles in the industries of water treatment, papermaking, mining, petroleum, and agriculture are described. In the further embodiments of the invention, the oily phase of the water-in-oil emulsion or the water-in-oil microemulsion is recovered, and purified in yet another embodiment, said oily phase being surprisingly substantially free of substances that weaken the polymerization. All patents, patent applications, books and articles mentioned herein are incorporated by reference therein.

BRIEF DESCRIPTION OF THE INVENTION According to the present invention, there is provided a process for the production of water-swellable, water-swellable, substantially dry, vinyl addition polymer particles comprising (a) spray-drying a dispersion, water-in-oil emulsion or Water-in-oil microemulsion, which contains vinyl-added polymer, in a gas stream with a residence time of about 8 up to about 120 seconds and an exit temperature of about 70 ° C to less than 100 ° C and (b) the collection of the resulting polymer particles. In yet another embodiment there is provided a process for the production of polymeric agglomerates with addition of vinyl, substantially dry, water-soluble or water-swellable, comprising (a) the spray-drying of a water-in-oil or water-in-oil microemulsion emulsion. , which contains vinyl-added polymer, in a gaseous stream, with a residence time of about 8 to about 120 seconds and an exit temperature of about 70 ° C to about 100 ° C, (b) the collection of the particles resulting polymerics, and (c) the agglomeration of the polymer particles to form agglomerates. In still another embodiment, a process is provided for the production of substantially water-dried, water-swellable, or water-soluble polymer particles from a mixture, comprising: (a) spray drying a mixture comprised of, or made by the intermixing of (i) a first dispersion, water-in-oil emulsion or water-in-oil microemulsion, containing water-swellable, water-swellable or water-soluble polymer, and (ii) a second dispersion, water-in-oil or water-microemulsion emulsion in oil containing water-swellable or water-soluble vinyl-added polymer in a gaseous stream with a residence time of from about 8 to about 120 seconds and an exit temperature of from about 70 ° C to about 150 ° C and (b) the collection of the resulting polymer particles. In yet another embodiment, a process is provided for the production of substantially dry, water-soluble or water-swellable polymeric agglomerates from a mixture comprising: (A) spray-drying a mixture comprised of, or made by, the mixed with, (I) a first water-in-oil or water-in-oil microemulsion emulsion containing polymer with addition of vinyl, water soluble or water swellable, and (II) a second water-in-oil or water-in-oil microemulsion emulsion containing vinyl addition polymer, water-soluble or water-swellable, in a gaseous stream with a residence time of from about 8 to about 120 seconds and an exit temperature from about 70 ° C to about 150 ° C, (B) the collection of the resultant polymer particles, and (C) the agglomeration of the resulting polymer particles. In yet another embodiment, a process is provided for the production of substantially dry, water-soluble or water-swellable polymer agglomerates, comprising (a) spray-drying a dispersion, water-in-oil emulsion, water-in-oil microemulsion, which contains polymer with addition of vinyl, (b) the collection of the resulting polymer particles; and (c) the agglomeration of the resulting polymer particles.

In yet another embodiment, a process for recovering the oil from a spray-drying process of a water-in-oil, water-in-oil or water-in-oil-containing microemulsion or dispersion containing water-soluble vinyl-added polymer comprising ( a) the condensation of oil and water generated in the spray drying process, to obtain condensed oil and condensed water; and (b) separating the condensed oil from the condensed water, wherein the condensed oil is substantially free of non-gaseous substances that weaken the polymerization. In yet another embodiment, a process for the purification of the oil generated by the spray-drying process is provided, comprising (a) a water-in-oil microemulsion, water-in-oil emulsion or dispersion containing polymer with addition of vinyl, soluble in Water; (b) the recovery of the oil generated by the spray drying process, to obtain recovered oil; (c) mixing the recovered oil with aqueous liquid, to obtain purified oil; and (d) separating the purified oil substantially free of non-gaseous substances that weaken in the polymerization.

In a further embodiment, there is provided a process for purifying the oil generated by the spray drying process comprising (a) the spray drying of a water-in-oil emulsion or microemulsion containing water-soluble polymer with addition of vinyl , within a gas stream with a residence time of about 8 to about 120 seconds, and at an outlet temperature of about 70 ° C to about 120 ° C or an outlet temperature of about 70 ° C to about 95 ° C; (b) the collection of the resulting polymer particles; (c) the recovery of the oil generated by the spray drying process, to obtain recovered oil; (d) mixing the recovered oil with aqueous liquid to obtain purified oil; and (e) separating the purified oil substantially free of non-gaseous substances that weaken the polymerization. In a further embodiment, water-soluble or water-swellable, substantially dry, polymeric particles comprised of a functionalized polymer, or a polymer having leaving group selected from the group consisting of amide, tertiary aminomethyl, quaternized tertiary aminomethyl, hydroxyl, glyoxal, sulfonate, sulfonate salt, carboxylic acid, carboxylic acid salt, hydroxamic acid, hydroxamic acid salt, dialkylaminoalkyl (ale) acrylate, dialkylaminoalkyl (ale) acrylate salts, and quaternized dialkylaminoalkyl (ale) acrylate, said particles having a bulk density from about 0.4 grams per cubic centimeter to about 1.0 grams per cubic centimeter, as well as substantially dry, water-soluble or water-swellable polymer agglomerates resulting from the agglomeration of these particles, and a method for the treatment of suspended solids , which comprises (a) dissolving, dispersing or mixing the polymer agglomerates substantially dry, water soluble or swellable in water, with or in water, to form a polymer solution, polymer dispersion or an aqueous mixture, (b) mixing the solution polymer, the dispersion or the aqueous mixture are suspended solids, and (c) the separation of the resulting concentrated solids from the resulting aqueous liquid. Finally, the substantially water-dried, water-swellable, or water-swellable polymer particles are prepared by a process comprising (a) spray-drying a dispersion, water-in-oil emulsion or water-in-oil microemulsion, containing polymer with addition of vinyl, within a gaseous stream with a particular residence time, preferably in the range of from about 8 to about 120 seconds. , and at a particular outlet temperature in the range of about 70 ° C to less than 100 ° C, and (b) the collection of the resulting polymeric particles, said polymeric particles having a lower drying loss of: (i) the loss by drying substantially water-dried, water-swellable or water-swellable polymer particles made by a process comprising (a) spray-drying the dispersion, the water-in-oil emulsion or the water-in-oil microemulsion containing the polymer with addition of vinyl, in a gaseous stream with a residence time greater than about 120 seconds and at a particular exit temperature, and (b) the collection of the resulting polymer particles; or (ii) the drying loss of substantially water-dried, water-soluble or water-swellable polymer particles made by a process comprising (a) spray-drying the water-in-oil emulsion, water-in-oil microemulsion or dispersion that it contains vinyl-added polymer, within a gaseous stream with a particular residence time and at an exit temperature greater than about 100 ° C and (b) the collection of the resulting polymeric particles; or (iii) the drying loss of substantially water-dried, water-soluble or water-swellable polymer particles made by a process comprising (a), spray-drying the water-in-oil emulsion, water-in-oil microemulsion, or dispersion. containing the vinyl-added polymer, within a gaseous stream with a residence time greater than about 120 seconds and at an exit temperature greater than about 100 ° C, and (b) the collection of the resulting polymeric particles, as well as the polymeric agglomerates substantially dry, water-soluble or water-swellable resulting from the agglomeration of these particles, and a method for the treatment of suspended solids, comprising (a) dissolving, dispersing or mixing the substantially dry polymer agglomerates , soluble in water or swellable in water, with or in water to form a polymer solution, polymer dispersion or aqueous solution, (b) the mixing of the polymer solution, the dispersion or the aqueous mixture with the suspended solids, and (c) the separation of the resulting concentrated solids from the resulting aqueous liquid.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES According to the present. invention, the dispersions, water-in-oil emulsions and water-in-oil microemulsions containing polymer with addition of vinyl, are spray-dried by means of a suitable medium into a large chamber through which a hot gas is blown, thereby it removes most or all volatile compounds and the recovery of the dry polymer becomes possible. Surprisingly, the means for spray drying the dispersion, water-in-oil emulsion or water-in-oil microemulsion within the gas stream, are not particularly critical and are not limited to pressure nozzles having specific orifice sizes; in fact, any known spray drying apparatus can be used. For example, means that are well known in the art such as rotary atomizer, pressure nozzles, pneumatic nozzles, sonic nozzles, etc., can all be used to spray-mist the dispersion, the water-in-oil emulsion or the water microemulsion. in oil in the gaseous stream. The feeding speed, the feed viscosity, the desired particle size of the spray-dried product, the droplet size of the dispersion, the water-in-oil emulsion or the water-in-oil microemulsion, etc., are factors that they are typically considered when selecting the dew media. The size and shape of the chamber, the number and type of spray media, and other typical operational parameters may be selected to adapt them to the conditions of the dryer using the common knowledge of those skilled in the art. Although open-cycle spray dryers can be used, closed cycle spray drying systems are preferred. The gas flow can be co-current, countercurrent or mixed flow, co-current flow being preferred. The hot gas or the inlet gas can be any gas that does not react or forms explosive mixtures with the feed and / or the spray-dried polymer. Suitable gases used as the inlet gas are gases known to those of skill in the art, including air, nitrogen and other gases, which will not cause undesirable degradation or contamination of the polymer, preferably gases containing about 20% or less of oxygen, more preferably about 15% or less of oxygen. More preferably, inert gases such as nitrogen, helium, etc., which contain about 5% or less of oxygen, are those which must be used. The dried polymer can be collected by various means such as simple outlet, sorting cone, bag filter, etc., or the polymer can be subjected to further drying steps, such as by fluidized beds, or agglomeration. The means for collecting the dry polymer product are not critical. The hot gas that remains substantially after all the polymer is removed from the feed generally contains volatile products such as oil, water, etc., and can be vented to the atmosphere or recovered, preferably recovered, and more preferably after that. , recycled. The oil is generally recovered from a spray-drying process of a water-in-oil emulsion, water-in-oil or dispersion microemulsion, containing polymer with addition of vinyl, by condensing the oil generated by the spray-drying process , preferably co-condensing the oil generated by the spray-drying process and the water generated by the spray-drying process, and separating the condensed or recovered oil from the condensed water. Said separation is easily achieved simply by draining the lower layer and / or pumping the upper layer, since water and oil are essentially immiscible. The difference in the boiling points between the water and the oil can be such that the condenser can be operated at a temperature to condense only the oil, reducing the energy costs associated with the condensation of the vaporized water. However, it has surprisingly been found that the co-condensation of water and oil can be beneficial, since the recovered or co-condensed oil is in general substantially free of non-gaseous substances that weaken the polymerization. The volatile compounds are preferably condensed or co-condensed with a dew condenser. The spray condensers are well known to those skilled in the art and function by spraying a liquid in hot gas, causing the hot gas to cool and causing the volatile oil, water, etc., contained in the gas hot, condense. The dew condenser may use an aqueous liquid, preferably water, more preferably aqueous acid, still more preferably aqueous inorganic acid, for example, aqueous sulfuric acid. Substances that weaken polymerization are those that inhibit or retard polymerization, or act as chain transfer agents. The chain transfer agents that weaken the polymerization can have chain transfer constants of about 10"4 or greater Preferably, the condensed, co-condensed or recovered oil contains less than about 0.1% of such substances that weaken the polymerization, more preferably less than about 0.05% by weight based on the total weight.

In some cases, the recovered oil, which may be co-condensing or condensing oil, may not be free of impurities or substances that weaken the polymerization, as desired. The recovered oil can be purified by intermixing the recovered oil with aqueous liquid to obtain purified oil and separating the purified oil from the resulting aqueous liquid. The oil purified in this manner is typically substantially free of non-gaseous substances that weaken the polymerization, and is generally suitable for use in subsequent polymerizations. Said aqueous liquid is preferably water, more preferably aqueous acid. Said acid is preferably an inorganic acid, more preferably sulfuric acid. In a preferred embodiment, a water-in-oil emulsion or water-in-oil microemulsion, which contains vinyl-added polymer, is composed of an oil recovered from a water-in-oil or water-in-oil microemulsion spray-drying process, containing polymer. The purified oil and the recovered oil can be treated to remove gaseous substances that weaken the polymerization, such as ammonia, oxygen, methylene chloride, dimethylamine, formaldehyde, etc., by known means such as by purification with an inert gas, for example nitrogen, helium, etc. One way to determine whether a treated, recovered, or modified oil is substantially free of non-gaseous substances that weaken the polymerization, is to use a particular oil to prepare a dispersion, water-in-oil emulsion or water-in-oil microemulsion, containing polymer with addition of vinyl, which is subsequently spray-dried, and then recover the condensed or co-condensed oil and, optionally, purify the recovered oil. If the resulting recovered or purified oil is substantially free of non-gaseous substances that weaken the polymerization, molecular weight or viscosity of the polyacrylamide solution prepared by polymerization or co-polymerization of the acrylamide in a water-in-oil or water-microemulsion emulsion in oil using said particular oil, they will generally be substantially the same as the molecular weight or viscosity of the polyacrylamide solution prepared by the polymerization of the polyacrylamide in a dispersion, water-in-oil emulsion or water-in-oil microemulsion using said recovered oil or purified, under otherwise substantially identical conditions. In one embodiment of the present invention, the level of formaldehyde in the recovered or purified oil, obtained by spray-drying a dispersion, water-in-oil emulsion or water-in-oil microemulsion, preferably a poly- (ale) acrylamide microemulsion of Quaternized mannich is typically less than one hundred milligrams of formaldehyde per kilogram of recovered or purified oil, preferably less than ten milligrams of formaldehyde per kilogram of purified recovered oil, and still more preferably less than one milligram of formaldehyde per kilogram of recovered or purified oil . Formaldehyde can be harmful to certain types of polymerization processes, so that a much reduced level of formaldehyde in the recovered or purified oil is a substantial advantage. It is economically and substantially advantageous to recycle the oil for use in other processes, including the same or other polymerization processes. The lack of oil and certain residual chemical reagents from the post-reaction step, in particular formaldehyde, in the polymer particles, are also substantial environmental advantages. There are four interrelated operating parameters in the present spray drying process: the gas inlet temperature, the gas outlet temperature, the volatile compounds of the product and the residence time in the dryer. The outlet temperature should generally be about 150 ° C or less, preferably about 120 ° C or less, more preferably less than 100 ° C, even more preferably about 95 ° C or less, and most preferably about 90 ° C or less. The outlet temperature is generally about 70 ° C or higher, preferably about 75 ° C or higher. Therefore, the outlet temperatures are generally from about 70 ° C to about 150 ° C, preferably from about 70 ° C to about 120 ° C, more preferably from about 70 ° C to less than 100 ° C, furthermore preferably from about 70 ° C to about 95 ° C, and most preferably from about 75 ° C to about 90 ° C. Exit temperatures below about 70 ° C may be adequate in certain cases, although in general this is less preferred. For example, at the expense of efficiency, spray drying can be carried out at extended residence times, at high gas flow rates and at low exit temperatures. In general, the dryer should be operated at the lowest exit temperature as possible, consistently with obtaining a satisfactory product. To facilitate obtaining at the lowest possible operating temperature, the dispersion, water-in-oil emulsion or water-in-oil microemulsion containing polymer with addition of vinyl, is preferably comprised of a volatile oil. "Volatile", for purposes of this invention, means that the boiling point or upper end of the oil boiling range is about 200 ° C or less, preferably about 190 ° C or less, more preferably about 180 ° C or less. Although the use of an oil having a boiling point or upper end of the boiling range greater than 200 ° C may be acceptable in some cases, the use of volatile oil allows spray drying of the dispersion, water emulsion in oil or water-in-oil microemulsion containing the polymer with the addition of vinyl, so that it is carried out at low exit temperatures, so that degradation of the polymer is prevented or substantially reduced. Although in theory an oil with a very low boiling point, ie at room temperature or lower, could be more preferable to avoid product degradation, in practice oils with low boiling points in this range can, under some circumstances, being unacceptable for other reasons related to handling and flammability. Thus, oils having a boiling point in the range of about 70 ° C to 190 ° C, preferably about 130 ° C to about 185 ° C, more preferably about 160 ° C to about 180 ° C are used. . Suitable oils, useful herein, include any organic hydrocarbon liquids such as halogenated hydrocarbons, aliphatic hydrocarbons, aromatic hydrocarbons, mixtures of aromatic and aliphatic hydrocarbons, etc., which usually contain about 6 to about 12 carbon atoms. Preferred examples of suitable hydrocarbons include perchlorethylene, benzene, xylene, toluene, mineral oil fractions, kerosenes, naphthas, petroleum fractions, and the like. A more preferred oil is a material called Isopar G manufactured by Exxon Chemical. Isopar G is a mixture of synthetic isoparaffinic hydrocarbons having a boiling point range from about 160 ° C to about 177 ° C. The inlet temperature, the feed rate, and the composition of the polymer emulsion can all affect the exit temperatures. These parameters can be varied to provide a desired output temperature. The feed rates are not critical and will generally vary depending on the size of the dryer and the velocity of the gas flow. The temperature of the inlet gas is less critical than the outlet gas temperature, and is generally about 140 ° C or higher, preferably about 160 ° C or higher. The temperature of the inlet gas is preferably about 200 ° C or less, and more preferably about 180 ° C or less. Thus, the temperature of the preferred inlet gas is in the range of about 140 ° C to about 200 ° C, more preferably about 160 ° C to about 180 ° C. Suitable inlet gas temperatures tend to avoid product degradation on the high side and prevent inadequate drying on the low side. The residence time is a nominal value obtained by dividing the volume of the dryer between the volumetric flow of the gas. The residence time is generally at least about 8 seconds, preferably at least about 10 seconds. The residence time is generally not greater than about 120 seconds, preferably not more than about 90 seconds, more preferably not more than about 60 seconds, and more preferably not more than about 30 seconds. Therefore, the general residence time range is from about 8 to about 120 seconds, preferably from about 10 to about 90 seconds, more preferably from about 10 to about 60 seconds, and even more preferably from about 10 to about 30 seconds. . It is known to those skilled in the art that longer residence times have to be expected when larger dryers are used or when the dryer is run less efficiently. For example, at the expense of efficiency, longer residence times could be expected at very low inlet temperatures and at slow gas flow rates. As a practical matter, the residence times useful in the present invention may vary from the values described above, depending on the size and type of the spray dryer used, the efficiency at which it is operated, and other operational parameters. In this way, the residence times specified herein may be modified to conform to the conditions of the dryer, using the common knowledge of those of skill in the art. Any dispersion, water-in-oil emulsion or water-in-oil microemulsion, containing polymer with addition of vinyl, soluble in water or swellable in water, can be spray-dried, by the processes of the present invention. For purposes of this invention, water-swellable polymers are generally those that have been cross-linked to a certain degree, preferably by forming the polymer in the presence of certain amounts of cross-linking or branching agents. Preferably, the water-swellable polymers include microspheres of US Pat. Nos. 5,274,055 and 5,167,766. Branched polymers, soluble in water, generally result when smaller amounts of the crosslinking agent are used to formulate the polymer, as in US Patent Applications Nos. 08 / 455,419 and 08 / 462,922. More preferably, the dispersion, water-in-oil emulsion or water-in-oil microemulsion containing water-swellable or water-soluble vinyl-added polymer is as described in U.S. Patent Nos. 4,956,399; 4,956,400; 5,037,881; 5,132,023; 5,286,806; 4,767,540; 5,274,055; 5,167,766; U.S. Patent Applications Serial Nos. 08 / 626,297, 08 / 455,419; and 08 / 462,922, which are all incorporated by reference herein. The polymer content with addition of vinyl of the dispersion, water-in-oil emulsion or water-in-oil microemulsion is generally about 10% or more, preferably more than 15%, more preferably about 17% or more, and still more preferably 20% or greater, by weight based on total weight. Preferably, the dispersions, water-in-oil emulsions or water-in-oil microemulsions containing the vinyl-added polymer are comprised of a polymer having leaving groups selected from the group consisting of amide, tertiary aminomethyl, quaternized tertiary aminomethyl, hydroxyl, glyoxal , sulfonate, sulfonate salt, carboxylic acid, carboxylic acid salt, hydroxamic acid, hydroxamic acid salt, dialkylaminoalkyl (ale) acrylate, dialkylaminoalkyl (ale) acrylate salts, and quaternized dialkylaminoalkyl (ale) acrylate. In this way the polymer can be Mannich poly (ale) acrylamide, quaternized Mannich poly (ale) acrylamide, hydroxamated polyacrylamide, esterified (meth) acrylic acid polymer, esterified (meth) acrylic acid copolymer and hydrolyzed polyacrylamide. The hydrolyzed polyacrylamide can be formed by inadvertent hydrolysis during production, but is preferably reacted after, for example, it is deliberately reacted with acid or base at a degree of hydrolysis of 5 mol% or greater, preferably 10 mol% or higher , based on the total moles of the preferred units, more preferably as described in U.S. Patent No. 5,286,806. The polymer may contain recurring units selected from the group consisting of acrylamide, dialkylaminoalkyl (ale) acrylate, dialkylaminoalkyl (ale) acrylate salts, quaternized dialkylaminoalkyl (ale) acrylate, (meth) acrylic acid, and (meth) acrylic acid salts. Preferred polymers include (1) a polymer containing 10 mol% or more of recurring units having overhang groups selected from the group consisting of carboxylic acid and carboxylic acid salt and having a standard viscosity of at least about 8.0 cps, ( 2) a polymer containing 20 mol% or more of recurring units having overhangs selected from the group consisting of carboxylic acid and carboxylic acid salt, and having a standard viscosity of at least about 9.0 cps, (3) a polymer containing at least about 1 mol% of tertiary aminomethyl groups, (4) an acrylamide polymer containing at least about 1 mol% of quaternized tertiary aminomethyl groups, (5) an acrylamide polymer containing at least about 1 mol% of hydroxamic acid or hydroxamic acid salt groups, (6) an esterified polymer containing hydroxamic acid groups and g carboxylic acid moieties or salts thereof, and (7) an organic, ionic polymeric microsphere, which is less than about 750 nanometers in diameter if it is crosslinked and less than about 60 nanometers in diameter if it is not crosslinked and insoluble in water, the ionicity of the microsphere at least about 1%, preferably having 1 mol% or more of recurring units having protruding groups selected from the groups consisting of carboxylic acid and carboxylic acid salt. Acrylamide polymers and copolymers are particularly preferred. In a preferred embodiment, the water-in-oil or water-in-oil emulsion microemulsion, which contains vinyl-added polymer, is a water-in-oil emulsion or microemulsion containing a Mannich poly (ale) acrylamide or Mannich poly (ale) acrylamide. Quaternized Water-in-Mannich polyacrylamide oil and quaternized Mannich polyacrylamide microemulsions can be heat treated before spray-drying, in accordance with the methods described in the North American Patent Application Serial No. 08 / 018,858 filed on February 12, 1993, which is incorporated by reference herein. The present invention is of particular value for the preparation of substantially dry, functionalized or post-reacted polymers. In many cases the functionalized polymers are those that can be reacted or that have been reacted later, for example a chemical reaction has been carried out on the polymer after the formation of the polymer from the corresponding monomers, see for example the Patent North American No. 4,956,400. The chemical reaction is generally deliberate or deliberate, and polymers that are inadvertently and indifferently reacted, for example, slightly hydrolyzed during the course of production, are not generally considered to be functionalized. For example, the Mannich poly (ale) acrylamides, the quaternized Mannich poly (ale) acrylamides, the acid or base hydrolyzed polyacrylamides, the hydroxamated poly (ale) acrylamides, etc. they are functionalized polymers that are difficult or impossible to prepare in the form of a solution or a gel.

Since the usual means for the preparation of the dry polymers is by means of a gel polymerization or in solution as described above, the dispersion, water-in-oil emulsion and the water-in-oil microemulsion may be the only practical method for the preparation of functionalized or post-reacted polymers. The dispersions, water-in-oil emulsions or water-in-oil microemulsions containing polymer with addition of vinyl, water-soluble or water-swellable of the present invention, are generally prepared by polymerization of the corresponding monomers, preferably as described in U.S. Patent Nos. 4,956,399; 4,956,400; 5,037,881; 5,132,023; 5,286,806; 4,767,540; 5,274,055; 5,167,766; and U.S. Patent Applications Serial Nos. 08 / 626,297; 08 / 455,419; and 08 / 462,922. The monomers can be polymerized in a dispersion, water-in-oil emulsion or water-in-oil microemulsion; the water-in-oil or water-in-oil microemulsion emulsion is preferred. All of the dispersions, emulsions and microemulsions described herein are reverse or water-in-oil. An emulsion for purposes of this invention, is generally defined as a composition comprising two liquids or phases which are insoluble one in the other, together with a surfactant, a mixture of surfactant or an emulsifier. A microemulsion, for purposes of this invention, is generally defined as a thermodynamically stable composition comprising two liquids or phases which are insoluble to one another, together with a surfactant, mixtures of surfactants or an emulsifier. The polymeric reverse microemulsions which contain a continuous oily phase and a discontinuous phase containing polymer (usually aqueous) are prepared from thermodynamically stable monomeric microemulsions. The reverse microemulsions have a narrow droplet size distribution and are usually, but not always, optically transparent. The discontinuous phase of a microemulsion, which contains the polymer, forms droplets or micelles, which are usually aqueous or usually have a droplet diameter, average, by volume, which is less than about 2500 A, preferably less than about 2000 A, and more preferably less than about 1000 Á. Some microemulsions may have an average droplet diameter, by volume, as large as about 3000A. Water-in-oil emulsions are well known in the art, see for example Vanderhoff in U.S. Patent No. 3,284,393. For purposes of this invention, dispersions are compositions comprised of polymer spheres or droplets that are dispersed in a non-aqueous liquid, for example, oil, generally with reduced levels of surfactant, but in general including other types of stabilizers, as described for example in U.S. Patent Nos. 4,528,321; 4,628,078; and 4,506,062. The homopolymers and copolymers of the monomers listed herein are fully encompassed by the present invention. Preferred nonionic monomers are water soluble monomers such as (meth) acrylamide, N-vinylpyrrolidone, N, N-dialkyl (meth) acrylamide, hydroxyalkyl (meth) acrylate, N-vinylformamide and the like. Small amounts, for example, about 10% or less, of other monomers having limited solubility in water may also be used, for example, methyl acrylate, styrene, methyl methacrylate, acrylonitrile, vinyl acetate, etc., with the proviso that the resulting polymer is water soluble or swellable in water. In general, water-swellable polymers are crosslinked, non-polymeric polymers containing as many water-insoluble recurring units that they swell without dissolving in water. Acrylamide and methacrylamide are especially preferred nonionic monomers. However, in some cases the polymer may contain 80% or even 100% non-ionic monomer, preferably, the polymer contains about 50% less nonionic monomer, preferably about 40% or less, more preferably about 30% or less per mole, based on the total moles of repeating polymer units. Water-swellable polymers or water-soluble branched polymers can be produced by copolymerization with multifunctional branching agents, for example, methylenebisacrylamide. Useful cationic monomers include dialkylaminoalkyl (ale) acrylate and dialkylaminoalkyl (meth) acrylamide quaternary salts and quaternaries, and diallyldialkyl ammonium halide. Preferred quaternization agents are methyl chloride, ethyl chloride, benzyl chloride, dimethyl sulfate, and diethyl sulfate. Preferred cationic monomers include the methyl chloride salt of dimethylaminoethyl (meth) acrylate, the methyl chloride salt of dimethylaminopropyl (meth) acrylamide, and diallyldimethylammonium chloride. Preferably, the polymer contains about 5% or more of cationic monomer, preferably about 10% or more, more preferably about 30% or more in mole, based on the total moles of the repeating polymeric units. Useful anionic monomers include acid (meth) acrylic, fumaric acid, crotonic acid, maleic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid is tyrosulfonic and salts thereof. Sodium and ammonium salts are preferred. Preferred anionic monomers include sodium acrylate, potassium acrylate, ammonium acrylate, and the sodium salt of 2-acrylamido-2-methylpropropanesulfonic acid. In general, the polymers contain sufficient of the salt form of the acid, such that the polymer is water-soluble or water-swellable, preferably more than 50% of the acid monomers are in the salt form, more preferably 60% or more by weight based on the total weight.

Preferably, the polymer contains about 5% or more of anionic monomer, preferably about 50% or more, more preferably about 70% or more, and most preferably about 75% or more per mole, based on the total moles of the units polymeric that are repeated. The polymerization can be carried out in the presence of conventional additives, as desired. For example, the polymerization may contain chelating agents for. eliminate polymerization inhibitors, chain transfer agents, pH adjusters, initiators and other conventional additives. The polymerization of the monomers can be carried out in any manner known to those skilled in the art. The initiation can be effected with a variety of initiators by free radicals, thermal and redox, including peroxides, for example t-butyl peroxide; azo compounds, for example azobisisobutyronitrile; organic compounds, such as potassium persulfate and redox pairs, such as ferrous ammonium sulfate / ammonium persulfate. A preferred initiator is sodium bromate / sulfur dioxide. The addition of the initiator can be effected at any time before the actual polymerization per se. The polymerization can also be carried out by photochemical irradiation processes, such as ultraviolet irradiation or by ionizing irradiation from a source of cobalt 60. The surfactants and / or dispersing agents are generally helpful and sometimes necessary for the formation and stability continuous dispersions, water-in-oil emulsions and water-in-oil microemulsions containing polymer with addition of vinyl. Where spray drying is contemplated, subsequent stability may not be required, and it may be advantageous to reduce or eliminate the surfactants and / or dispersing agents. The dispersions, water-in-oil emulsions and water-in-oil microemulsions containing vinyl-added polymer, can be prepared using little or no surfactant and / or dispersing agent, and spray-dried shortly thereafter, preferably during the period of continuous stability. Preferably, the dispersions, water-in-oil emulsions and water-in-oil microemulsions containing vinyl-added polymer, contain about 2% or less of surfactant and / or dispersing agent, more preferably about 1% or less, by weight based on the total weight. The spray dried polymer particles, made by the processes of the present invention, preferably contain 6% or less of surfactant and / or dispersing agent, preferably 4% or less. The substantially water-soluble or water-swellable polymeric particles can be produced from a mixture by (a) spray-drying a mixture comprised of, or made from, the mixing of (i) a first dispersion, water emulsion in oil or water-in-oil microemulsion containing polymer with addition of vinyl, soluble in water or swellable in water and (ii) a second dispersion, water-in-oil emulsion or water-in-oil microemulsion containing polymer with addition of vinyl, soluble in water or inflatable in water, and (b) the collection of the resulting polymer particles. Preferred mixtures of water-in-oil emulsions and water-in-oil microemulsions are described in the Patent Application North American Nos. Of Series 08 / 157,764 and 08 / 157,795. The mixing of the water-in-oil emulsions and water-in-oil microemulsions can advantageously provide a product with improved performance for example by providing a property such as charge or molecular weight that is different from the individual emulsions or microemulsions from the which the mixture is derived. Different property may result from the average properties of the components of the mixture, or occasionally synergistic results may be observed. For example, when treating substances that are themselves mixtures or combinations of various components, each of the components of the mixture may have a specific role in the operation of the product. Accordingly, although two identical water-in-oil emulsions and water-in-oil microemulsions could be mixed, it is generally preferred to mix the emulsions or microemulsions which are different from one another, for example with different operation, different charge, different viscosity, different molecular weight, different physical form, different chemical identity, different aging characteristics, different costs, etc. Spray drying of the mixtures is advantageous because typically 90% or more, preferably 95% or more, more preferably substantially all of the resultant spray dried polymer particles individually contain two or more polymers with added vinyl • , soluble in water or swellable in water so that the effects of stratification can be minimized. Spray drying of a mixture can be particularly advantageous when the first water-in-oil emulsion or water-in-oil microemulsion containing the water-insoluble or water-swellable vinyl addition polymer has a viscosity that is different from the viscosity of the water. second water-in-oil emulsion or water-in-oil microemulsion, which contains the polymer with addition of vinyl, soluble in water or swellable in water. This is because the viscosity in general has an impact on the particle size distribution of the spray dried polymer particles, so that the particle size distribution of the particles obtained from the first emulsion water in oil or microemulsion Water in oil may be different from the particle size distribution of the particles obtained from the second water-in-oil emulsion or water-in-oil microemulsion. A dry mixture of the two different polymers is thus likely to show greater stratification than a dry mixture obtained from the spray drying of a mixture of the first and second water-in-oil emulsions or water-in-oil microemulsions. In yet another embodiment of the present invention, the Mannich and Quaternary Mannich polymer particles have, in some cases, residual contamination substantially reduced by certain chemical reagents added during the functionalization step, for example formaldehyde, methyl chloride and amines. Typically, the residual level of methyl chloride in the polymer particles is below 500 parts per million (ppm), based on the total weight of the particles, and preferably below 100 ppm, on the same basis. The formaldehyde is typically below 2000 ppm and preferably below 1000 ppm, on the same basis. Individual residual amines, which may be present as their hydrochloride salts, are typically present below 20,000 ppm and preferably below 10,000 ppm, on the same basis. With respect to the various spray dried and agglomerated polymer products, described herein, the optimum standard viscosity for a particular polymer is very application dependent, for example the flocculation of suspended solids, of paper making, of oil recovery, in mining, etc. For example, for many applications, it is preferred that the standard viscosity of the polymer particles be about 1.5 centipoise or greater, more preferably about 2.0 centipoise or greater, more preferably about 2.5 centipoise or greater. However, the different applications of flocculation were to require polymers with standard viscosities greater than or less than those given above. An advantage of the present invention is that the standard viscosity of the polymer particles produced according to the processes described herein, are generally from about 15% of the standard viscosity of the polymer dispersion, of the water-in-oil or water-based emulsion. the corresponding polymeric water-in-oil microemulsion. This indicates that the polymers are not substantially altered by the spray drying process. In general, the polymers of the present invention have a molecular weight of about 100,000 or greater, preferably greater than about 1,000,000, more preferably greater than about 10,000,000, and more preferably greater than about 20,000,000. The optimum molecular weight or molecular weight range for a particular polymer is also very dependent on the application, for example in the flocculation of suspended solids, papermaking, oil recovery, mining, etc. For example, for many flocculator applications, Mannich polyacrylamide and quaternized derivatives thereof have an average molecular weight greater than about 100,000 and preferably greater than about 1,000,000.

However, applications other than flocculation may require polymers with molecular weights greater than or less than those given above. The water soluble polymers produced by the processes described herein may contain small amounts of insoluble polymer. Such small amounts of insoluble polymer do not generally affect the operation of the polymer for example in the applications indicated above. In some cases, water-swellable polymers are desired for applications such as fluid thickening, papermaking, thickeners for printing inks, etc. When produced according to the spray drying processes described herein, the polymer particles of the present invention are generally about 10 microns or larger in diameter, preferably about 40 microns or more, more preferably about 100 microns. micrometers or greater, more preferably approximately 200 micrometers or greater. It is preferred that the polymer particles be non-dusting. The problems of dust formation and flow are typically exacerbated when the polymer particles are small, so that the larger polymer particles are generally desirable. However, very large particles can dissolve more slowly. Therefore, it is generally desirable that the polymer particles be about 1200 microns or less in diameter, preferably about 800 microns or less in diameter, more preferably about 600 microns or less, and still more preferably about 400 microns or less. less. In general, at least about 90% of the polymer particles are in the range of about 10 microns to about 1200 microns, preferably at least about 95%, more preferably at least about 98%. The size of the polymer particles can be varied to some extent by altering the operational parameters, for example, the spray pattern, the viscosity of the emulsion, the feed rate, etc. The particles can be substantially. spherical or non-spherical; the "diameter" of a non-spherical particle is the dimension along a major axis. Although in some cases the particles are hollow, the porous structures have at least one opening in their walls, it has been found that these characteristics are not always necessary in order to obtain particles having desirable properties, for example rapid dissolution times. In many cases, the spray-drying parameters, for example the type of nozzle, the nozzle size, the exit temperature, etc., necessary to produce particles that are hollow, the porous structures having at least one opening in their Walls are inconvenient or non-economic, and it is advantageous to produce particles that lack some or all of these characteristics. The particles formed by the spray drying processes of the present invention can be screened to remove a larger or smaller size fraction. The larger sized particles can be fragmented for example by grinding, while the smaller sized particles are generally agglomerated. Sizes can be determined by methods known to those of skill in the art for example, sieving, selection, light scattering, microscopy, microscopic automated image analysis, etc. Surprisingly, the apparent densities of the spray-dried polymer particles of the present invention are generally greater than the apparent densities of the dry polymers prepared by precipitation of the dispersion, the water-in-oil emulsion or the corresponding water-in-oil microemulsion. Polymeric particles having higher densities can be advantageous, because they occupy a smaller volume, resulting for example in lower shipping and storage costs.

While the densities of the precipitated polymers are usually less than about 0.35 grams per cubic centimeter (g / cc), the apparent densities of the spray dried polymer particles of the present invention are generally about 0.35 g / cc or greater , preferably of about 0.4 g / cc or greater, more preferably of about 0.45 g / cc or greater, more preferably of about 0.50 g / cc or greater. The apparent densities of the spray dried polymer particles of the present invention are generally about 1.1 g / cc or less, preferably about 1.0 g / cc or less, more preferably about 0.95 g / cc or less, more preferably still of approximately 0.90 g / cc or less. Therefore, the apparent densities of the spray-dried polymer particles of the present invention are generally in the range of from about 0.35 to about 1.1 g / cc, preferably from about 0.4 to about 1.0 g / cc, more preferably about 0.45 to about 0.95 g / cc, and still more preferably from about 0.50 to about 0.90 g / cc. Under the drying conditions described herein, the polymer particles produced by the processes described herein are substantially dry. As used to describe the polymer produced herein, "substantially dry" generally means that the polymer contains about 12% or less of volatile products, preferably about 10% or less by weight, based on the weight of the dried polymer by dew. The polymer generally contains about 2% or more volatile products, preferably about 5% or more, based on the total weight, and more preferably contains from about 8% to about 10% volatile compounds by weight, on the same basis . The volatile compounds are measured by determining the weight loss after drying the polymer product at about 105 ° C for about 30 minutes. The water-soluble or water-swellable, substantially dry polymer particles of the present invention can be made by a process comprising (a) spray-drying a dispersion, water-in-oil emulsion or water-in-oil microemulsion containing polymer with adding vinyl, in a gaseous stream for a particular residence time, preferably in the range of about 8 to about 120 seconds, and at a particular outlet temperature in the range of about 70 ° C to less than about 100 ° C and ( b) the collection of the resulting polymer particles. These polymer particles are encompassed within the present invention when they have a loss after drying less than: (i) the drying loss of water-soluble or water-swellable substantially water-soluble polymer particles, made by a process comprising (a) ) the spray drying of the dispersion, water-in-oil emulsion or water-in-oil microemulsion, containing polymer with addition of vinyl, in a gaseous stream with a residence time greater than about 120 seconds and at a particular exit temperature, and ( b) the collection of the resulting polymer particles; or (ii) the drying loss of substantially water-soluble or water-swellable polymer particles, made by a process comprising (a) spray-drying the dispersion, water-in-oil emulsion or water-in-oil microemulsion, which it contains polymer with addition of vinyl, in a gaseous stream with a particular residence time and at an exit temperature greater than about 100 ° C, and (b) the collection of the resulting polymer particles; or (iii) the drying loss of water-soluble or water-swellable polymer particles substantially dry processed by a process comprising (a) spray-drying the dispersionwater-in-oil emulsion or water-in-oil microemulsion, containing polymer with addition of vinyl, within a gaseous stream for a residence time of approximately 120 seconds and an exit temperature greater than approximately 100 ° C, and (b) the collection of the resulting polymer particles. As used herein, "loss by drying" is the change in viscosity of the polymer that results from spray drying, and does not have to be confused with the "loss after drying", or LOD, which is a measure of the volatile compounds as described in the Examples. The drying loss can be expressed as the viscosity before spray drying, minus the viscosity after spray drying, divided by the viscosity before spray drying, and expressed as a percentage by multiplication by 100. Additional materials such as such as flow control agents, powder control agents, pH adjusting agents, surfactant, emulsifier, etc. and the like, can be added to the emulsion or microemulsion before or during the spray drying process, or to the polymer particles after the spray drying process, or both, to improve production, distribution, packaging, handling , operation, etc., and the like of polymer particles. It has also been discovered that it may be advantageous to mix, in any order, an acid, a base or a buffer in the water-dried, substantially dry polymer particles which are the product of the spray drying processes described herein. . A buffer, for purposes of this invention, is a substance or mixture of substances that, when dissolved in water, gives a solution that resists changes in pH when small amounts of acid or base are added. Preferably, the buffer contains an acid and a base. For example, any solution of a weak acid plus a salt of that acid is a buffer solution. A base, for purposes of this invention, is a substance or mixture of substances that, when dissolved in pure water, gives a solution with a pH value greater than 7. An acid, for purposes of this invention, is a substance or mixture of substances that, when dissolved in pure water, gives a solution with a pH value of less than 7. The addition of an acid, base or buffer to the polymer particles can improve the flow properties of the dried polymer particles and adjusts the pH of the solution in which the polymer particles are dissolved, to improve the dissolution rate and the operation of the polymer particles in the desired application. The bases are more preferred and the dampers are most preferred. Acids, bases and buffers useful in the present invention may be solid or liquid, although it is especially preferred to use an acid, base or buffer that is substantially dry to prevent agglomeration. Substantially dry, when used to describe the acid, base or buffer for purposes of this invention, means that the acid, base or powder buffer flows freely. The acid, base or buffer can be hydrated as long as it flows freely. Any basis known in the art can be used. Suitable powder bases can include the alkali metal and alkaline earth metal salts of carbonate, bicarbonate, citrate, phosphate and acetate. Preferred bases may include sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, sodium acetate, potassium acetate, sodium citrate, potassium citrate, sodium phosphate, potassium phosphate, etc., and the like. . Sodium carbonate and sodium bicarbonate are more preferred, and sodium bicarbonate is most preferred. The mixture of the base and the polymer particles is such that the base can be incorporated into the interior of the particles, or it can coat the surface of the particles, or it can be different from the particles, or any combination thereof. Any shock absorber known in the art can be used. Suitable buffers may comprise the alkali metal and alkaline earth metal salts of carbonate, bicarbonate, citrate, phosphate and acetate, with the corresponding acid. The mixture of the buffer and the polymer particles is such that the base can be incorporated into the interior of the particles, or it can coat the surface of the particles, or it can be different from the particles, or any combination thereof. The buffer system KH2P04 / Na2HP04, or hydrates thereof, is the most preferred. Any acid known in the art can be used. Suitable acids may comprise inorganic acids for example, hydrochloric acid, nitrous acid, nitric acid, carbonic acid, phosphoric acid, phosphorous acid, sulfurous acid, and sulfuric acid, as well as organic acids, for example, acetic acid, lactic acid, acid citric acid, formic acid, alkylsulfonic acids, and the like. Acids such as KH2P0, NaH2P04 and hydrates thereof are preferred. In cases where a Quaternary Mannich polyacrylamide microemulsion is thermally treated by, for example, adjusting the pH from about 3.6 to about 4.8 by adding formaldehyde scavenger, adjusting the water content to about 10-45 weight percent polymer and by heating the resulting emulsion at about 40 ° C to about 80 ° C for about 3 to about 20 hours, the acid is preferably added in addition to and after the heat treatment step. It is preferred to add the acid, base or buffer directly to the polymer particles. Alternatively, and less preferably, an acid, base or buffer, can be dissolved in water or oil to form a solution or suspension and added to the dispersion, water-in-oil emulsion or water-in-oil microemulsion containing the vinyl-added polymer. , soluble in water or swellable in water, before spray drying. The solution or suspension of the acid, the base or the buffer can be spray-dried simultaneously or substantially simultaneously with the spray-drying of the water-in-oil or water-in-oil microemulsion emulsion, or the acid, the base or the buffer they can be added directly to the spray dryer while simultaneously or substantially simultaneously spray-drying the water-in-oil emulsion or the water-in-oil microemulsion, to form the polymer particles, which comprise the acid, the base or the buffer. In this case, the acid, base or buffer does not need to be substantially dry or anhydrous. Another less preferred way to add one or more acids, bases or buffers to the polymer is to add part of the acid, base or buffer, before or during the spray drying process, and part of the acid, base or of the buffer or perhaps an acid, base or buffer different from the resulting polymer particles. The buffer can be formed when a base is added to a water-in-oil emulsion or water-in-oil microemulsion or a polymeric particle which already contains the corresponding acid, or the buffer can be formed when an acid is added to a water-in-oil emulsion or water-in-oil microemulsion or the polymeric particle that already contains the corresponding base. The amount of acid, base or buffer to be added to the water-soluble Mannich acrylamide or the quaternized Mannich acrylamide polymer particles of the present invention is preferably a sufficient amount to provide a solution pH of about 5%. to about 11, preferably from about 5.5 to about 9 and more preferably from about 6 to about 8, when the particles or particle compositions dissolve in water. Regardless of the manner in which the acid, base or buffer is added (for example, whether it is added to the emulsion before or during spray drying or to the particles after spray drying) the amount must be be such that the resulting solution containing the dissolved polymer particles has a pH of at least about 5, preferably at least about 6 and below about 11, preferably a pH below about 8. It is understood that the pH of the The resulting solution will depend on the pH of the water before the polymer particles are added. For example, in order to produce a preferred pH in the resulting solution in the range of about 5 to about 9, in general more base should be present in the particles if the water is more acidic than if the water is less acidic. It is likewise understood that the preferred amount of base present in the polymer particles may depend on the pH of the water within which the polymer particles are to be dissolved. For example, for many waters of moderate acidity, the polymeric particles should contain about 0.1% to about 3.5% based on the total weight of a preferred base such as sodium bicarbonate. In general, the polymer particles may contain the base in an amount of at least about 0.05% by weight, preferably at least about 0.1% and in general up to about 10.0%, preferably up to about 20.0% by weight based on the total weight of the particle. More preferably the amount of base is in the range of about 0.05% to about 5.0%, based on the total weight of the particles. The aforementioned amounts also apply to acids. A similar reasoning is understood concerning the optimum amount of the acid; for example, the presence of more acid will be preferred in the particles when the water is more basic than when the water is less basic, in order that the polymer solution has the desired pH. Routine experimentation by one of skill in the art can be used to determine the appropriate amount of acid, base or buffer to a particular water. Similarly, the amount of buffer will depend on the pH of the water, before the polymer particles are added. The amount of buffer present will tend to affect the ability of the polymer solution to resist changes in pH. For example, for a preferred buffer system, such as KH2P04 / Na2HP04 »12H20, the buffer should be at least about 0.1% by weight, and preferably at least about 5% by weight, of the total weight of the particles. Although it would seem preferable to use as much buffer as possible to provide the polymer solution with the greatest ability to withstand changes in pH, it is also preferable that the polymer particles contain as much polymer as possible. Thus, in practice, the buffer must comprise less than 50% by weight of the polymer particles, and preferably less than 30% by weight, on the same basis. Therefore, the buffer must be present in the polymer particles at a level of at least about 0.05%, generally from about 0.1% to about 50% by weight, and preferably from about 5% to about 30% by weight, with based on the total weight of the particle. The exact amount of buffer depends on the pH of the water and how strongly the polymer solution needs to be able to withstand changes in pH. In addition to pH, another factor that tends to influence the rate of dissolution of the polymer particles and the operation of the polymer is the temperature of the polymer solution or the solution within which the polymer particles are dissolved. Therefore, the amount of acid, base or buffer present in the polymer particles may vary depending on the temperature of the water within which the polymer will dissolve. For example, quaternized Mannich polyacrylamide tends to dissolve more rapidly at higher temperature, so that a lower pH, such as about 5, may be desired to dissolve the polymer when the water temperature is higher, such as about 35. ° C, while a pH of about 8 may be preferred if the water temperature is very low, such as about 5 ° C. It is apparent, therefore, from the foregoing that less base or more acid can be preferred at high temperatures, than at low temperatures, and that the selection of the buffer will also depend on the temperature. The particle size of the acid, base or buffer is not particularly important, and can be varied to optimize the flow properties of the mixture with the polymer particles. For example, a preferred range of particle sizes for sodium bicarbonate is from about 10 to about 500 microns, more preferably from about 50 to about 300 microns. The means for adding and mixing the substantially dry base to the polymeric particles are likewise non-critical. Any means of mechanical mixing, known to those skilled in the art, for mixing granular solids is suitable. It has also been discovered that the agglomeration of the polymer particles of the present invention can improve the flow properties and the dissolution times of the polymers. Agglomeration is a known process for increasing particle size and various methods for agglomerating the particles are known to those skilled in the art, for example, "Successfully Use Agglomeration for Size Enlargement," by Wolfgang Pietsch, Chemical Engineering Progress, April 1996, pp. 29-45; "Speeding up Continuous Mixing Agglomeration with Fast Agitation and Short Residence Times," by Peter Koening, Powder and Bulk Engineering, February 1996, p. 67-84. Known agglomeration methods such as natural agglomeration, mechanical agglomeration, drum agglomeration or growth, pressure agglomeration, agglomeration without binder, agglomeration with binders, etc., can be used to agglomerate the polymer particles of the present invention. The agglomeration may optionally be followed by drying, for example, fluidized bed drying, to remove the binder, for example water. Pressure agglomeration is preferred, and mechanical agglomeration using an aqueous binder followed by fluidized bed drying is still more preferred. The agglomerates formed by the agglomeration of the polymer particles of the present invention tend to have improved flow properties and faster decay times, when compared to the non-agglomerated polymer particles. Preferably, the agglomerates are not powder formers. The flow properties can be measured by measuring the flow times, as described in the Examples. The rates of dissolution can be determined by measuring the increase in viscosity of a polymer solution as a function of the dissolution time, as described in the Examples. Typically, about 90% of the agglomerates of the present invention have an agglomerate size of about 120 microns or greater, preferably about 160 microns or greater, more preferably about 200 microns or greater, and most preferably about 300 microns or greater. In general, about 90% of the agglomerates have an agglomerate size of about 1500 microns or less, preferably about 1200 microns or less, more preferably about 1100 microns or less, and most preferably about 1000 microns or less. Thus, about 90%, preferably 95% of the agglomerates have a size in the range of about 120 to about 1500 microns, preferably about 160 microns to about 1200 microns, more preferably about 200 microns to about 1100 microns, and more preferably from about 300 micrometers to about 1000 micrometers. Usually, at least about 5% of the agglomerates, preferably at least about 10%, and still more preferably at least about 15% are greater than about 900 microns. The agglomerates formed by the agglomeration of the spray-dried particles of the present invention can be screened to remove a larger or smaller size fraction. Preferably, agglomerates greater than about 1200 microns and smaller than about 175 microns are removed, for example, by sieving. The larger sized agglomerates are generally fragmented for example by milling, while the smaller sized agglomerates are generally recycled to the agglomerator. The bulk density values of the agglomerates of the present invention tend to be lower than the apparent density values of the spray-dried particles from which they are formed. The apparent densities of the agglomerates of the present invention are generally 0.35 g / cc or greater, preferably about 0.4 g / cc or greater, more preferably about 0.45 g / cc or greater, and still more preferably about 0.50 g. / cc or greater. The apparent densities of the agglomerates of the present invention are generally about 1.0 g / cc or less, preferably about 0.95 g / cc or less, more preferably about 0.90 g / cc or less, and still more preferably about 0.85 g / cc or less. Therefore, the bulk densities of the agglomerates of the present invention are generally in the range of from about 0.35 to about 1.0 g / cc, preferably from about 0.4 to about 0.95 g / c, more preferably from about 0.45 to about 0.90 g. / cc, and even more preferably from about 0.50 to about 0.85 g / cc. In order to obtain agglomerates of a preferred size, it is preferred that the polymer particles themselves be of a size such that they are agglomerable. The agglomeration obviously tends to multiply the average particle size, so that it is often easier to cause large increases in particle size than to cause small increases in the size of the particle. Therefore, in order to produce the agglomerates of a preferred size or a preferred size range, it is generally preferred to agglomerate the particles which are much smaller than the desired size of the agglomerate, instead of the particles which are only slightly smaller. The agglomerable particles are generally those which can be conveniently agglomerated to produce agglomerates having a preferred size It is possible, but less preferred, to agglomerate the larger particles to produce agglomerates that are larger than desired, and to eliminate then the larger size agglomerates as described above The substantially dry polymer particles and the agglomerates of the present invention are generally comprised of the polymer that was contained in the dispersion, water-in-oil emulsion or water-in-oil microemulsion that was spray-dried , as discussed previously in the present. , the substantially dry and agglomerated polymer particles of the present invention are comprised of the polymer having leaving groups selected from the group consisting of amide, tertiary aminomethyl, quaternized tertiary aminomethyl, hydroxyl, glyoxal, sulfonate, sulfonate salt, carboxylic acid, carboxylic acid, hydroxamic acid, hydroxamic acid salt, dialkylaminoalkyl (ale) acrylate, dialkylaminoalkyl (ale) acrylate salts, and quaternized dialkylaminoalkyl (ale) acrylate. Polymers and copolymers of acrylamide are preferred. In a preferred embodiment, substantially water-soluble or water-swellable polymeric agglomerates and water-swellable particles are comprised of a polymer having 1 mole or more of recurring units having leaving groups selected from the group consisting of tertiary aminomethyl, quaternized tertiary aminomethyl, glyoxal, hydroxamic acid, and hydroxamic acid salt, based on total moles of recurring units. In another preferred embodiment, the agglomerates and substantially dry polymer particles, soluble in water, are comprised of a polymer having 1 mol% or more of recurring units having protruding groups selected from the group consisting of carboxylic acid and carboxylic acid salt, based on the total moles of the recurring units, said polymer having a standard viscosity of about 7.0 cps or greater, and in another preferred embodiment the polymer is further comprised of recurring units having outstanding alkyl ester groups, wherein the groups Alkyl ester comprise from about 2 to about 12 carbon atoms. In another preferred embodiment, agglomerates and polymer particles substantially dry, water-soluble or water-swellable, are comprised of acrylamide, (meth) acryloxyethyltrimethylammonium chloride, copolymers thereof, and, optionally, a branching agent, eg, methylenebisacrylamide. , as described in US Patent Applications Serial Nos. 08/455, 419 and 08 / 462,922. In another preferred embodiment, the agglomerates of substantially water-dried and water-soluble polymer particles are comprised of a polymer having 10 mol% or more of recurring units having leaving groups selected from the group consisting of carboxylic acid and carboxylic acid salt and wherein the polymer has a standard viscosity of at least about 8.0 cps, or (b) wherein said polymer contains 20 mol% or more of recurring units having leaving groups selected from the group consisting of carboxylic acid and carboxylic acid salt, wherein the polymer has a standard viscosity of at least about 9.0 cps. In another preferred embodiment, agglomerates and water-soluble polymer particles substantially dry, are comprised of organic, ionic polymeric microspheres, which are less than about 750 nanometers in diameter if crosslinked, and less than about 60 nanometers in diameter if they are not crosslinked , and insoluble in water, the ionicity of the microspheres being at least about 1%. The substantially dry polymer particles and agglomerates of the present invention generally show improved stability relative to the dispersion, the water-in-oil emulsion, or the water-in-oil microemulsion from which they are derived. For example, Table 7 shows the change in standard viscosity as a function of time at 90 ° C for the quaternized, spray-dried Mannich polyacrylamide, as compared to a quaternized Mannich polyacrylamide microemulsion from which it was derived. the spray-dried polymer. The standard viscosity of the polymer in microemulsion changed substantially as a function of time, while the change in the standard viscosity for the spray-dried polymer was much lower. Table 8 shows the data obtained in a similar manner, except that the dry polymer and the microemulsion polymer were stored at room temperature. Again, the standard viscosity of the polymer in microemulsion changed substantially as a function of time, while the change in the standard viscosity for the spray-dried polymer was not substantial. In both cases, at room temperature and at 90 ° C, it is very surprising that the spray-dried polymer shows greater stability, as measured by the standard viscosity, than the corresponding polymer contained in the microemulsion. Surprisingly, the standard viscosities of the polymer particles and the agglomerates that are the product of the process described herein, are not substantially reduced by the spray drying process of the invention. In general, the standard viscosity values of the polymer particles are not decreased by more than about 15% of their initial value, preferably not more than about 10%, more preferably not more than about 8%, more preferably not more than about 5%. %, as a result of the spray-drying process, even when the polymer's standard viscosity in water-in-oil microemulsions containing polymer, is observed to rapidly decrease at elevated temperatures, as described hereinabove. It is also surprising that short residence times result in polymer particles with low levels of volatile compounds. In addition, the residual level of the oil in the finely divided polymer particles is typically very low, usually less than 1.0% by weight, based on the total weight of the particles, and preferably less than 0.2% by weight, on the same basis. The agglomerates of water-soluble, substantially dry, free-flowing polymer particles, which are the product of the present invention, can be used in many applications, such as, for example, separation of solids / liquids.; floculadsres for mining operations to recover metallic ore from the suspensions; flocculators for water treatment, to eliminate suspended impurities, etc .; in the manufacture of paper as a flocculator and to assist in the formation of paper, for example, retention aids; in oil recovery industries, for example, improved oil recovery, treatment of oily waste water, etc .; in agriculture, for example, for soil stabilization or soil conditioning; in biotechnological applications, for example, in the treatment of enzymatic broths; and in food processing, for example, for flocculation of suspended food particles. The polymers of the present invention may conveniently be employed, for example, as flocculants in the form of dilute aqueous solutions. These solutions can be prepared by mixing, dispersing and / or dissolving the particles in or with water. The concentration of the dispersions of suspended solids is carried out by the addition of an effective amount of the diluted aqueous solution to the suspension, to produce an effluent of desired characteristics.

For example, a preferred method for the treatment of suspended solids comprises (a) dissolving, dispersing or mixing the substantially dry, water-soluble or water-swellable polymer particles or agglomerates, in or with water to form a polymer solution, polymer dispersion or aqueous mixture, (b) mixing the polymer solution, dispersion or aqueous mixture with suspended fluids, and (c) separating the resulting concentrated solids from the resulting aqueous liquid. The polymeric products of this invention are useful in a wide range of solid-liquid separations. These polymers can be used in the dehydration of biologically treated suspensions, such as drainage or other municipal and industrial sludges, the draining of the cellulosic suspension, such as those found in the production of paper, for example, waste paper, in the production of paper, for example, retention aids, and in the sedimentation of various organic or inorganic suspensions, for example, refinery waste, food waste, etc. Similarly, enzymatic broths and suspended mineral solids can be treated in a similar way. The dose of the polymer, effective for a particular application, is generally found by routine experimentation in a manner well known to those of skill in the art. Preferred doses are in the range of about 0.1 parts of the polymer per million (ppm) to about 10,000 ppm, based on the weight of the solids suspended in the substrate to be treated. When the particles are produced in such a way that they are not soluble in water, but rather swellable in water, they can be dispersed in water to form aqueous mixtures comprised of dispersions of water-swellable polymers. Water-swellable polymers may be useful for applications such as paint thickening, papermaking, for example, as described in US Patent No. 5,274,055 and in US Patent No. 5,167,766, and as thickeners for ink inks. Print. The following examples are described for purposes of illustration only, and are not to be construed as limiting the present invention.

PROOF PROCEDURES The standard viscosity is the viscosity of a 0.096% solution of the water-soluble polymer in 1 N sodium chloride at 25 ° C, at a pH of 8.0 for non-ionic and anionic polymers, and at a pH of 7.0 for cationic polymers, except where specified. The viscosity was measured by a Brookfield LVT viscometer with a UL adapter at 60 rpm. The polymer solution that was measured was made by preparing a 0.20% solution of the polymer in deionized water for two hours, and then diluting with the appropriate amounts of deionized water and sodium chloride. Volatile content (percentage loss after drying, LOD) was determined using a Sartorius Model MA30 Moisture Analyzer. The dried polymer sample was dried at a specific temperature, either at a constant weight or for a specified time. A period of 30 minutes at 105 ° C provided a reliable and reproducible indicator of the volatile content of the product. The results are reported as volatile percentage by weight based on total weight.

The water analysis of the volatiles was carried out by Karl Fisher titration. The residual oil levels in the dry products were determined by extracting the sample with supercritical carbon dioxide and gas chromatography analysis of the extractant. The residual formaldehyde in the recovered oil was determined by stirring the oil recovered with water for thirty minutes, then analyzing the water extractant by ion chromatography. The laboratory spray dryer, used in the following Examples, was obtained commercially. The laboratory spray dryer chamber was 760 millimeters (mm) in diameter with a vertical side of 860 mm and a conical bottom at 65 degrees. The nominal gas flow through the dryer was approximately 180 cubic meters per hour. The feed of the emulsion or microemulsion was made in the center of the upper part of the chamber using a variable speed pump, through a nozzle of two fluids, using air for atomization. The outlet gas temperature was controlled by varying the inlet gas temperature and the feed rate. To provide an inert atmosphere, the dryer was supplied with nitrogen gas from a cryogenic storage tank. The dried polymer product was discharged through the bottom of the dryer cone, into a cyclone where the dried product was removed and collected. The residence time in the dryer was generally about 10-15 seconds. Some examples of spray drying were performed with a closed-cycle spray dryer, 2.53 m (8.3 ft) in diameter equipped with a spray condenser by direct contact. The products of the spray dried polymer particles were agglomerated using a commercial mechanical agglomerator in conjunction with a 1 m2 (10.76 square foot) fluid bed dryer. The agglomerator had a vertical axis and a flexible polymer housing, with a simple shaft rotor having 2 or 3 pin or paddle type mixing elements, rotating from 1500 to 5200 revolutions per minute (rpm). This was equipped with mechanically driven rollers that moved along the flexible housing of the polymer, to prevent the accumulation of material along the walls. The spray-dried product and the binder, for example water, were fed to the top of the agglomerator; the polymer spray-dried by means of the screw feeder, and by means of the spray nozzles. The agglomerates formed by the agglomeration of the spray dried polymer particles fell off the bottom of the agglomerator and directly into a fluidized bed dryer, where the agglomerates were dried to the desired water content. The typical residence time in the agglomerator was approximately two seconds. The purpose of the funnel flow test is to identify the funnel in which the polymer particles and agglomerates fall to flow, either uncontracted and compacted. The funnel flow test is conducted using five funnels, numbered 1-5, respectively, which have the following output diameters; 14 mm, 12 mm, 8 mm, 5 mm, 3.5 mm. The procedure is followed by starting with funnel 5 (3.5 mm outlet), blocking the exit, filling the funnel with the polymer to be tested and unblocking the outlet to allow the polymer to flow. If all the polymer passed through the funnel, the polymer was given a rating of +5. If the polymer failed to flow from the funnel when the outlet was unblocked, the procedure was repeated with funnel 4, funnel 3, etc., until the flow was observed. The funnel number was recorded when flow was no longer observed. The process was then repeated to determine the flow of the compacted polymer, hitting the funnel slightly approximately 20 times (or placed on a suitable vibrating plate) to create the compaction. For example, a polymer with a rating of +5, +5 flowed through funnel number 5 in both tests, while a polymer with a rating of +5.3 flowed, through funnel number 5 not compacted, but not It was able to flow through funnel number 3 when it was compacted. The bulk density of the polymer particles and the agglomerates was determined by the addition of the particles or agglomerates to a suitable measuring container, previously weighed and "tapping" or by shaking the container slightly to cause the particles or agglomerates to they nod. The volume of the polymer was then read from the measuring vessel, the measuring vessel was weighed, and the bulk density was calculated in units of grams per cubic centimeter (g / cc).

The dissolution times were determined by the addition of 0.2 parts of polymer particles or agglomerates to 99.8 parts • of deionized water in a suitable vessel and stirring with a magnetic stir bar. The apparent viscosity of the mixture was measured at regular intervals for example five or ten minutes, using a Brookfield LVT viscometer with a UL adapter of 60 rpm, until a maximum apparent viscosity was reached, for example until no further increase in viscosity was observed. . the apparent viscosity. The time to achieve this maximum apparent viscosity was recorded as the dissolution time and was generally not more than a few hours. In the following Examples, quaternized Mannich polyacrylamide microemulsions (Cat. PAM) were prepared as in US Patent No. 4,956,399, except that Isopar G was used as the oil. Hydrolyzed polyacrylamide emulsions were prepared as described in US Pat. No. 5,286,806, except that Isopar G was used as the oil. Copolymer microspheres were prepared in emulsion and in microemulsion of highly crosslinked acrylamide / acrylic acid, as described in US Pat. No. 5,274,055, except that Isopar G was used as the oil. The cationic emulsion copolymers of (meth) acryloxyethyltrimethylammonium chloride and acrylamide, and the anionic copolymers of acrylic acid and acrylamide, were prepared by known methods for example, Vanderhoff, in US Pat. No. 3,284,393, and the branched cationic polymers were prepared as in the North American Patent Application Serial No. 08 / 455,419, except that Isopar G was used as the oil in all cases. In all cases, the replacement of Isopar G by the other oil was on a volume basis. The sizes of the agglomerate and the polymer particles were determined by commercially available light scattering instrumentation, and by conventional screening techniques.

EXAMPLE 1 A microemulsion of polyacrylamide Quaternized Mannich (Cat. PAM) having a standard viscosity of about 2.5 was spray dried in a laboratory spray dryer, using a two fluid nozzle in a nitrogen atmosphere with gas inlet and outlet temperatures of 182 ° C and 92 ° C, respectively. The volatiles were 7.65% and the resistance time was 14 seconds. The standard viscosity of a solution of the dried product was 2.25 cps, 9.3% less than the standard viscosity of a solution of the microemulsion product. The polymer particles were in the size range of about 19 to about 900 microns. The level of residual products in the dried product was as follows: formaldehyde: 520 ppm; methylene chloride: less than 100 ppm; dimethylamine hydrochloride: 3724 ppm; trimethylammonium hydrochloride: 6248 ppm; tetramethylammonium hydrochloride: 5219 ppm.

EXAMPLE 2 (Comparative) The Cat. PAM of Example 1 was dried in a double drum dryer, vacuum, 30.5 cm (12 inches) by 45.7 cm (18 inches) with less satisfactory results. The temperature of the steam on the drum was 115 ° C, and the vapor pressure in the drums was 0.7 kg / cm2 (10 psig). The drum was operated at 6 revolutions per minute with a drum clearance of 0.25 millimeters (0.010 inches) and a vacuum of approximately 65 mm Hg. The feed rate was approximately 40.82 kg (90 pounds) of emulsion per hour. The volatiles percent and the Standard Viscosity are as described in Table 1. A comparison of the dry polymer produced herein to that of Example 1 shows that the Standard Viscosity was significantly reduced using the drum dryer.

Table 1 C: Comparative Example EXAMPLES 3-7 A Cat. PAM having a Standard Viscosity of approximately 2.5 was spray dried using a commercial 2.83 m (8.3 ft) diameter spray dryer with a rotary atomizer (rotating disk). The dryer was operated using air on a base one at a time. The various conditions of temperature and time, of residence used are described in Table 2: the residence time was 30 seconds for all runs. The product was collected at the base of the dryer (chamber) and at the discharge of a cyclone located immediately after the dryer. Table 2 also shows the analytical results of Examples 3-7; in each case, the polymeric product from each of the collection points (chamber and cyclone) was analyzed with the results as shown. In each case, the Standard Viscosity of the polymer particles was within 15% of the Standard Viscosity of the corresponding Cat. PAM.

Table 2 EXAMPLES 8-12 A Cat. PAM having a Standard Viscosity of approximately 2.5 was spray dried using a commercial spray dryer of 2.53 meters (8.3 feet) in diameter with a pressure nozzle atomizer. The dryer was operated as a closed cycle system using nitrogen gas.

The product was collected at the base of the dryer or the chamber. After recovering the polymer, the exit gas was passed through a direct contact condenser and the resulting aqueous and Isopar G layers were separated. The cooled gas was then reheated and returned to the dryer inlet; A very small fraction was ventilated. The level of residual formaldehyde in the recovered Isopar G was 0.09 milligrams / kilogram as measured after the completion of the five runs. The quality of the recovered Isopar G was such that it could be recycled and used directly for additional microemulsion or emulsion polymerizations. Table 3 provides the various conditions of the process; the residence time for all the runs was 24 seconds. The properties of the resulting dry polymer particles are as shown in Table 3. One to three samples of the polymer product were collected for each run and analyzed as shown. In each case, the Standard Viscosity of the polymer particles was within 15% of the Standard Viscosity of the Cat. PAM used for spray drying.

Table 3 EXAMPLE 13 A Cat. PAM having a Standard Viscosity of about 2.5 was buffered with urea / lactic acid until pH 4.5, then treated with heat by heating at 67-70 ° C for 7-9 hours, then allowed to cool to room temperature ambient. This heat treatment process is described in the North American Patent Application SN 08 / 018,858, filed on February 12, 1993. The resulting polymer microemulsion was then spray-dried in a laboratory spray dryer using a two fluid nozzle. The various conditions of temperature and residence time used are described in Table 4. As shown in the Table, the Standard Viscosity of the polymer particles was within 15% of the Cat. Standard Viscosity. Heat-treated PAM, corresponding . The levels of the residual products in the dried product were as follows: formaldehyde; 510 ppm; methylene chloride; less than 100 ppm; dimethylamine hydrochloride; 7500 ppm; trimethylamine hydrochloride: 6928 ppm; tetramethylammonium hydrochloride: 5671 ppm.

Table 4 EXAMPLE 14 The polymeric particles of Cat. PAM were obtained by the spray drying process of Example 1. To 97.5 parts of these granules were added 2.5 parts of sodium carbonate in a suitable vessel. The vessel was mechanically stirred for 30 minutes to form a composition containing substantially dried granules of quaternized Mannich polyacrylamide and sodium carbonate.

EXAMPLE 15 The Cat. PAM particles were obtained by the spray-drying process of Example 14 and then sodium carbonate was added according to the process of Example 14. The solutions of the particles were prepared by dissolving 0.2 parts of the particles in the sample. 100 parts of water. The dried particles took about 1 hour to dissolve. A sample of the heat-treated polymer microemulsion, described in Example 13, was also dissolved in water to produce a similar polymer concentration. Both polymers were left stirring in water for two hours, then tested for their ability to flocculate the suspended solids, using a digested sludge digested with 2.0% solids. Approximately 200 parts of the slurry was mixed at about 1000 rpm with various amounts of the polymer solutions, in the range of 10 parts to 50 parts, for about 5 seconds. After this, the drained speeds of the flocculated solids were measured at 10, 20 and 30 seconds. The polymer products worked equally well in the dose range of 11.34 to 13.61 kilograms (25 to 30 pounds) of the polymer per tonne of sludge.

EXAMPLE 16 The particles of Cat. PAM were prepared according to Example 14, except that sodium bicarbonate was used instead of sodium carbonate. The Standard Viscosity of these particles was determined, without pH adjustment, as 2.45 cps. In comparison, the Standard Viscosity (measured without the pH adjustment) of the Cat. PAM particles prepared by the procedure of Example 1, which did not contain a base, was measured as 1.3 centipoise. Standard Viscosity is known in the art to directly correlate with the operation of the polymer, for example, flocculation.

EXAMPLE 17C A polyacrylamide microemulsion was prepared as follows: A 149.75 parts Isopar G, 26.28 parts of Atlas G-1086 and 6.57 parts of Arlacel 83, 172.93 parts of an aqueous solution of pH 3.0 containing acrylamide were added slowly. (148.2 parts of a 53.3% solution), sodium bromate (1.16 parts of a 1% solution), 0.68 parts of isopropanol, and ethylenediaminetetraacetic acid (0.40 parts of a 40% solution) with stirring. The resulting monomeric microemulsion was purged for 40 minutes with nitrogen. The S02 gas was then bubbled into the resulting microemulsion and the polymerization temperature was kept below 65 ° C. The resulting product was a clear stable microemulsion having a Standard Viscosity of 3.07 centipoise.

EXAMPLE 18 The procedure of Example 17C was followed, except that the Isopar G recovered following the process of Examples 8-12, was used in place of the fresh Isopar G. The resulting product was a stable, clear microemulsion, having a standard viscosity of 3.03 centipoise, virtually the same standard viscosity as that which was obtained using fresh Isopar G (Example 17C).

EXAMPLES 19-23 A 20% hydrolyzed polyacrylamide emulsion having a polymeric solids content of 23.8% and a Standard Viscosity of 8.63 centipoises was prepared as described in US Pat. No. 5,286,806, except that Isopar G was used as the oil, then It was spray dried in a laboratory spray dryer using nitrogen. The inlet temperature, the outlet temperature and the feed rate were varied, and the LOD, the Standard Viscosity (SV), and the drying loss of the polymeric particles product, as shown in Table 5, were measured. they observed smaller losses by drying at the exit temperature of less than 100 ° C.

Table 5 C: Comparative Example EXAMPLES 24-36 A series of 13 water-in-oil emulsions or water-in-oil microemulsions containing vinyl addition polymer, water-soluble or water-swellable, were prepared according to the methods referenced below (except that Isopar was used). G as the oil), then spray-dried in a laboratory spray dryer using nitrogen, and the results shown in Table 6 were obtained. The hydrolyzed PAM emulsions were obtained by the hydrolysis of the polyacrylamide emulsions (PAM) as described in U.S. Patent No. 5,286,806 (Example 24-25). Acrylamide (AMD) and acrylic acid (AA) were copolymerized in emulsion to produce AMD / AA emulsions by known methods, for example Vanderhoff, US Pat. No. 3,283,393 (Examples 26-27). A hydroxamated acrylamide polymer with a degree of hydroxamation of about 40% (40% HX emulsion of Example 28) was prepared by the methods of US Patent No. 4,767,540. The microemulsion of acrylamide / acrylic acid microspheres of Example 29 was prepared by the methods of U.S. Patent No. 5,274,055. The water-soluble polyacrylate ester emulsion was prepared by the methods of US Patent Application No. 08 / 626,297 (Example 30). Acrylamide and acryloxyethyltrimethylammonium chloride (AETAC) were emulsion copolymerized to produce AMD / AETAC emulsions by known methods for example, Vanderhoff, in US Patent No. 3,284,393 (Examples 31-34); small amounts, of about 4 molar parts per million, based on the monomers, of methylenebisacrylamide were added to the AMD / AETAC polymers of Examples 32 and 34, to create the branching, see for example US Pat. Series 08 / 455,419. Mannich and Mannich quaternized microemulsions were prepared by the methods of US Pat. No. 4,956,399 (Examples 35 and 36). In each case, substantially dry, free-flowing mixtures of polymer particles having drying losses of about 15% were obtained.

Table 6 EXAMPLES 37-39 A 20% hydrolyzed polyacrylamide emulsion made with Isopar G was spray dried on a commercially available 2.53 meter (8.3 ft) diameter spray dryer using a direct contact spray condenser. The water and oil generated by the spray-drying process were collected and acidified, the layers were separated, and the top layer of Isopar G was recovered. Acrylamide polymerizations were then performed on a laboratory scale, side by side, using the recovered Isopar G and virgin Isopar G. The Standard Viscosity of the polyacrylamide elaborated using the recovered oil was 6.58 cps, virtually the same as the Standard Viscosity of the polyacrylamide elaborated using the virgin oil, 6.67 cps. Subsequently, a polymerization of acrylamide at a scale of 757 liters (200 gallons) was carried out using the same recovered Isopar G and the same formula as the laboratory scale batch. The resulting polyacrylamide had a Standard Viscosity of 6.55 cP, essentially the same as the laboratory batch.

EXAMPLES 40-41 A quaternized Mannich polyacrylamide microemulsion having a Standard Viscosity of about 2.1 was spray dried as in Example 1. The microemulsion and the polymer particles were placed inside an oven at 90 ° C, and the standard viscosities were determined at various temperatures. times, as shown in Table 7. The decrease in Standard Viscosity of the microemulsion sample was much greater than the modest decrease observed for the spray-dried polymer, despite the relatively severe conditions.

Table 7 EXAMPLES 42-43 A quaternized Mannich polyacrylamide microemulsion having a Standard Viscosity of about 2.5 was spray dried as in Example 1. The microemulsion and the polymer particles were stored at room temperature, and the standard viscosities were determined at various times, as shown in Table 8. The Standard Viscosity in the spray-dried polymer was not essentially affected by the passage of time, while that the Standard Viscosity of the polymer in microemulsion decreased markedly.

Table 8 EXAMPLES 44-49 An 20% anionic hydrolyzed PAM emulsion was obtained by the hydrolysis of a polyacrylamide emulsion (PAM) as described in US Pat. No. 5,286,806. A 55% cationic emulsion was obtained by the copolymerization of acrylamide and acryloxyethyl trimethylammonium chloride (AETAC) by the methods known, for example, from Vanderhoff, in US Patent No. 3,284,393. A Cat. PAM was obtained as in the North American Patent No. 4,956,399X In each case, Isopar G was used as the oil. Part of each sample was precipitated in hexane / acetone, then dried under vacuum to produce a polymer powder. Part of each sample was also spray dried, and part of each sample dried by dew was agglomerated. Bulk density, flow properties (funnel flow test), dissolution time and particle size were determined and are shown in Table 9. The particle size was determined by light scattering for the precipitated polymers and spray-dried, and by selection by mesh screening for the agglomerates.

Table 9 Comparative Example EXAMPLES 53-55 The agglomerates of Examples 46, 49 and 52 were screened to remove agglomerates greater than about 1190 microns and smaller than about 177 microns. The resulting sifted agglomerates had improved flow properties and improved dissolution times relative to the agglomerates of Examples 46, 49 and 52 as shown in Table 10.

Table 10 EXAMPLES 56-63 Emulsions of hydrolyzed, anionic PAM were obtained by hydrolysis of PAM polyacrylamide emulsions as described in US Pat. No. 5, 286,806, an 80% anionic emulsion was obtained by the copolymerization of acrylamide and acrylic acid (AMD / AA) by known methods, for example, Vanderhoff, in US Patent No. 3,284,393, and a microemulsion of Mannich was obtained as described in U.S. Patent No. 4,956,399, except that Isopar G was used as the oil in all cases. Each emulsion and microemulsion was spray dried according to the conditions shown in Table 11. Minor drying losses and faster dissolution times were observed when spray drying was conducted at lower exit temperatures.

Table 11 E JEMPLOS 64 - 65 A mixture of Cat. PAM and a cationic copolymer was prepared as in U.S. Patent Application Serial No. 08 / 157,764, and a cationic polymer dispersion was prepared according to the procedures of U.S. Patent No. 4,506,062 (without distillation). ), except that Isopar G was used as the oil. The mixture and the dispersion were spray dried in a laboratory spray dryer as in Examples 24-36. Substantial dry polymer particles were obtained, with drying losses of about 15% or less. More than 90% of the particles of the spray-dried mixture contained the Cat. PAM and the cationic copolymer.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, property is claimed as contained in the following:

Claims

1. A process for the recovery of oil, characterized in that it comprises: (a) the spray drying of a dispersion, water-in-oil emulsion or water-in-oil microemulsion containing polymer with addition of vinyl, soluble in water or swellable in water, (b) ) the co-condensation of oil and water generated by the spray drying process, to obtain condensed oil and condensed water; and (c) separating the condensed oil from the condensed water, to obtain recovered oil containing less than about 0.1% by weight, based on the total weight, of non-gaseous substances that weaken the polymerization.

2. The process according to claim 1, characterized in that the co-condensation is carried out in a dew condenser.

3. The process according to claim 2, characterized in that the spray condenser uses an aqueous acid.

4. The process according to claim 1, characterized in that it also comprises the addition of acid to condensed oil and condensed water, before separation.

5. The process according to claim 1, characterized in that it also comprises the treatment of the oil recovered by purging with an inert gas, to eliminate the gaseous substances that weaken the polymerization.

6. The process according to claim 1, characterized in that it further comprises the purification of the recovered oil, by mixing the recovered oil with aqueous acid, to produce purified oil, and separation of the purified oil from the resulting aqueous liquid.

7. The process according to claim 1, characterized in that the recovered oil contains less than 0.05% by weight, based on the total weight, of non-gaseous substances that weaken the polymerization.

8. The process according to claim 1, characterized in that the spray drying is carried out at an outlet temperature of about 70 ° C to about 150 ° C.

9. The process according to claim 1, characterized in that the spray drying is carried out at an exit temperature of about 70 ° C to less than 100 ° C.

10. The process according to claim 1, characterized in that the dispersion, water-in-oil emulsion or water-in-oil microemulsion containing the polymer "with addition of vinyl, soluble in water or swellable in water, is comprised of a polymer having (i) ) protruding groups selected from the group consisting of amide, tertiary aminomethyl, quaternized tertiary aminomethyl, hydroxyl, glyoxal, sulfonate, sulfonate salt, carboxylic acid, carboxylic acid salt, hydroxamic acid, and hydroxamic acid salt, or (ii) units Recursors selected from the group consisting of acrylamide, dialkylaminoalkyl (ale) acrylate, dialkylaminoalkyl (ale) acrylate salt, quaternized dialkylaminoalkyl (acrylate) acrylate, acrylic acid, and acrylic acid salt.

11. The process according to claim 10, characterized in that the polymer is soluble in water.

12. The process according to claim 10, characterized in that the polymer is swellable in water.

13. The process according to claim 10, characterized in that the polymer contains protruding groups selected from the group consisting of amide, tertiary aminomethyl, quaternized tertiary aminomethyl, hydroxyl, glyoxal, sulfonate, sulfonate salt, carboxylic acid, carboxylic acid salt, acid hydroxamic, and hydroxamic acid salt.

14. The process according to claim 10, characterized in that the polymer contains recurring units selected from the group consisting of acrylamide, dialkylaminoalkyl (ale) acrylate, dialkylaminoalkyl (ale) acrylate salt, quaternized dialkylaminoalkyl (ale) acrylate, acrylic acid, and salt Acrylic acid

15. The process according to claim 1, characterized in that the water-in-oil emulsion or water-in-oil microemulsion containing polymer with addition of vinyl, soluble in water is spray-dried in step (a).

16. The process according to claim 1, characterized in that the water-in-oil or water-in-oil emulsion containing water-swellable vinyl-added polymer is spray-dried in step (a).

17. The process according to claim 1, characterized in that the dispersion, water-in-oil emulsion or water-in-oil microemulsion containing the vinyl-added, water-soluble or water-swellable polymer, is comprised of (i) a first dispersion water-in-oil emulsion or water-in-oil microemulsion containing polymer with addition of vinyl, soluble in water or swellable in water, and (ii) a second dispersion, water-in-oil emulsion or water-in-oil microemulsion containing polymer with addition of vinyl , soluble in water or inflatable in water.