CN106519231B

CN106519231B - A kind of polyphenylene sulfide devil liquor recovery separating technology

Info

Publication number: CN106519231B
Application number: CN201510570807.3A
Authority: CN
Inventors: 华超; 白芳; 陆平; 邓前江
Original assignee: Institute of Process Engineering of CAS
Current assignee: Institute of Process Engineering of CAS
Priority date: 2015-09-09
Filing date: 2015-09-09
Publication date: 2019-03-19
Anticipated expiration: 2035-09-09
Also published as: CN106519231A

Abstract

The invention discloses a kind of polyphenylene sulfide devil liquor recovery separating technology, including three desk centrifuges, three driers, a crystallizing and drying device and a set of three towers low-pressure distillation system are formed.The present invention relates to a kind of polyphenylene sulfide devil liquor recovery separating technology, key is that develop the new process flow of one kind refines the separation of component in raw material more, the separation purity of product is higher, and operability is more preferable provided with three proprietary tower low-pressure distillation modes；By matching centrifugation and forced circulation drying equipment, avoids product attachment liquid phase and cause damages；In order to promote LiCl to crystallize, guarantees that LiCl product is precipitated faster, reduce thermal losses, evaporation crystallization equipment is increased between centrifuge separation and drier；By the application of new technological flow, keep the separation of product more energy-efficient, the collection of product more refines, and purity is more preferable, has good prospects for commercial application.

Description

A kind of polyphenylene sulfide devil liquor recovery separating technology

Technical field

It is specifically exactly to be related to polyphenylene sulfide devil liquor recovery separating technology the invention belongs to a kind of chemical engineering Material Field Innovation and improvement.

Background technique

Polyphenylene sulfide is a kind of thermoplastic special engineering plastic, developed into engineering plastics the sixth-largest kind and The big kind of the first of special engineering plastics.Its molecular backbone has good heat resistance, resistance to by constituting to penylene base and sulphur atom Chemical corrosivity, anti-flammability, electrical insulating property, mechanical strength and processing performance have been widely used for automobile, electronics, aviation The industrial departments such as space flight, precision instrument.

Although there are many method for synthesizing polyphenylene sulfide, realize that industrialized main method is that pressurization is closed both at home and abroad At polyphenylene sulfide.Pressurization synthesis technology is to use vulcanized sodium and paracide for raw material, and lithium chloride is catalyst, N- first Base -2- pyrrole network alkanone (NMP) is that solvent isolates PPS product after polycondensation reaction of being pressurizeed in a kettle.Production PPS's In the process, the units such as to synthesize, wash can generate a large amount of waste liquids, and 35% water, 5% paracide, 50% are contained in waste liquid The solid compounds such as the sodium chloride and lithium chloride of NMP (n-methyl-2-pyrrolidone) and 10%.Its filtrate is de- through one tower of rectifying After water separates sodium chloride, then through two tower of rectifying recycle most of solvent, the toughness raffinate that tower bottom excludes, after cooling it is curable at Dark brown waste residue.Through analyzing, which mainly contains cannot be by rectifying recovered solvent, catalyst, salt and a small amount of Oligomer or its carbonized product and other impurities.

Currently, the mostly of PPS manufacturer, country use are water washing polycondensation reaction thing filter cake recycling NMP technique, the technique Have that extractant is cheap and easy to get, nonflammable explosive, the nontoxic, ring of extraction phase compared with other organic solvent extraction and recovery NMP techniques Small, water is polluted in border and solvent NMP is easily separated, extractant not solvent slop, the advantages that process flow is short, solvent recovery is at low cost. But in actual application process, disadvantage is also than more significant: mixed solution is when vacuum batch distillation is dehydrated, since NMP is molten NaCl is not dissolved in agent, in dehydration, with the reduction of moisture in dehydration tower bottom of rectifying tower, a large amount of NaCl crystallizations are precipitated, knot Brilliant salt is easy to blocking tower reactor and pipeline when generating.Such case not only reduces heating efficiency, but also NaCl is made to be difficult to empty in time, Reduce the utilization rate of equipment.The NMP adhered on NaCl plane of crystal and kettle wall when cleaning tower reactor in kettle is rinsed water and takes away, The consumption of nmp solvent is not only increased, simultaneously because content of organics is excessive in discharge salt water, receives the utilization of effluent brine Considerable restraint.

If the residue discharged in production, it is bound to cause environmental pollution, and solvent therein and catalyst are expensive, It must be recycled, to reduce the production cost of PPS.It is subsequent how to improve solvent with the production-scale expansion of current PPS The rate of recovery of NMP recycles paracide, NaCl and LiCl, improves the separation purity of byproduct, it has also become production cost is reduced, It improves PPS resin and produces competitiveness, enhance enterprise's production economy benefit, the key subjects to reduce environmental pollution.

Summary of the invention

Present invention is generally directed to the recycling of the by-products such as solvent, catalyst in waste liquid caused by polyphenylene sulfide process units point Separating process develops a kind of completely new continuous production processes process.The application of the process keeps the separation of product more efficient, point It is higher from the purity of component, realize that effect is more preferable.The present invention improves NMP by innovative technology scheme and equipment usage mode The recovery efficiency of solvent reduces pollution of the salt to solvent, realizes the recycling of the classification to salt component, has significant warp Benefit of helping and environmental benefit.

To solve the above problems, the technical solution adopted by the present invention is that:

Waste liquid raw material initially enters centrifuge, and liquid parts are got rid of into dashpot, contains oligomer, other carbonized products or not The dehydration underflow of soluble solids impurity enters drier, and the dry moisture evaporated enters dashpot, the solid impurity after drying It is discharged to out-of-bounds.Solution in dashpot enters three tower low-pressure distillation systems, passes through three group of three tower rectification under vacuum, separation water outlet Point, paracide and nmp solvent.The NaCl concentrated solution that tower bottom is isolated enters centrifugal separator, and liquid parts return to three towers essence System is evaporated, NaCl underflow enters drier and is dried, and dry boil-off gas returns to dashpot, and dry NaCl is collected Processing.Another product LiCl that tower bottom is isolated is introduced into centrifuge and removes most liquid composition, is then evaporated knot Crystalline substance, the product after crystallization carry out further depth drying, then carry out the collection processing of LiCl product；It is centrifuged the liquid being precipitated The gaseous component steamed when component and crystallization and evaporation, depth drying enters dashpot and carries out rectifying separating treatment again.

Polyphenylene sulfide process units devil liquor recovery separating technology of the present invention, mainly include three desk centrifuges, three driers, One crystallizing and drying device and three proprietary tower low-pressure distillation systems.Entire process flow, provided with three proprietary tower low-pressure distillations Mode refines the separation of component in raw material more, and the separation purity of product is higher, and operability is more preferable, has fully demonstrated change Work process eats the net Advanced Idea of dry squeezing, realizes the further promotion and optimization of polyphenylene sulfide nmp solvent recovery process process.

Detailed description of the invention

The following further describes the present invention with reference to the drawings:

Fig. 1 is polyphenylene sulfide devil liquor recovery separation production procedure schematic diagram of the present invention.

Specific embodiment

Device and embodiment with reference to the accompanying drawing is further elaborated the present invention, but does not generate to the present invention any Limitation.

The invention polyphenylene sulfide process units devil liquor recovery separating technology, the flow diagram of the technique such as Fig. 1 It is shown, by impurity removed system, three tower rectification under vacuum systems and centrifugal drying system composition.

Generated waste liquid first carries out removal of impurities processing in PPS production process.Waste liquid enters centrifuge, the liquid phase isolated into Enter dashpot, the insoluble solid impurities isolated cause solvent recovery to prevent solid impurity from adhering to solvent and other components Loss, is further dried, and the gas phase evaporated returns to the dashpot before distillation system, and solid impurity collection is sent to boundary Outer processing；Solution in dashpot is sent to three tower rectification under vacuum units, respectively is isolated by moisture, the paracide of high-purity and molten Agent NMP and NaCl solution and LiCl solution.NaCl solution enters centrifuge, and the liquid phase of removing enters dashpot and continues to separate, Sticky solid phase is further dried, and causes solvent loss to prevent NaCl from taking away partial solvent；Similarly, LiCl solution enter from Liquid composition is isolated in scheming, and according to the difference of NaCl and LiCl physical property, the LiCl underflow needs for throwing away centrifuge are done further Evaporative crystallization processing, finally carry out depth drying again, could output high-purity LiCl crystal.LiCl solution is centrifugated institute Steam component caused by during the liquid composition and evaporative crystallization and depth drying of generation is back to surge tank progress It is further separated processing.In this way, both ensure that all components can obtain most sufficient recycling in waste liquid, also ensure separation NaCl and LiCl can have very high product purity.

Present invention has the advantages that polyphenylene sulfide process units devil liquor recovery separating technology arranges layout and work by innovation Skill flow scheme improvements, rationally, the extraction of various components more refines in product for design, and the purity of various component extraction greatly improves, Disposable yield reaches 90% or more, and product purity reaches 98% or more；To sum up several process innovations, whole device solvent return Good economic benefit and environmental benefit can be obtained in operation by receiving process.

A kind of polyphenylene sulfide process units devil liquor recovery separating technology proposed by the present invention, has passed through preferred embodiment Son is described, wherein the part that do not address in detail is the common knowledge of those skilled in the art.Protection model of the invention It encloses and is based on the contents of the claims, all similar replacements and change based on technical inspiration of the invention are considered as wrapping It includes in spirit of that invention, range and content.

Claims

1. a kind of devil liquor recovery separating technology of polyphenylene sulfide process units, which comprises the following steps: by waste liquid elder generation It is centrifuged off solid impurity ingredient, liquid parts are got rid of into dashpot, and processing is further dried in solid impurity；The liquid being centrifuged out into Three tower low-pressure distillation of row, generates different products, and three tower low-pressure distillation tower top products are moisture, the paracide of high-purity and molten Agent NMP, tower bottom product are NaCl solution and LiCl solution, are centrifuged and are dried to tower bottom product, and centrifugate and drying steam Gas return dashpot continue with；

During entire process flow, evaporation crystallization equipment is increased between the centrifuge separation and drying of LiCl, is conducive to LiCl salinity preferably crystallizes precipitation, reduces crystallization difficulty and thermal losses in drying process；

Drying unit is forced-circulation evaporation unit at three, and drying unit is respectively the dry single of solid impurity at described three The drying unit of member, the drying unit of NaCl and LiCl.

2. technique as described in claim 1, which is characterized in that solid impurity is oligomer, other carbonized products or insoluble Solid impurity.

3. technique as described in claim 1, which is characterized in that the drying unit of LiCl is depth drying.