CN1388127A - Pyromellitic acid dianhydride trapping method and apparatus - Google Patents
Pyromellitic acid dianhydride trapping method and apparatus Download PDFInfo
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- CN1388127A CN1388127A CN 01119323 CN01119323A CN1388127A CN 1388127 A CN1388127 A CN 1388127A CN 01119323 CN01119323 CN 01119323 CN 01119323 A CN01119323 A CN 01119323A CN 1388127 A CN1388127 A CN 1388127A
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Abstract
The present invention relates to the durene gas phase oxidizing process of producing pyromellitic acid dianhydride and passive hot wall-type sublimation trap. The trap consists of mixing chamber and trapping chamber with sublimation bed or deflecting structure, and has its wall temperature maintained in passive hot wall method. The product gas and cold inert gas are mixed and cooled directly inside the mixing chamber, and the produced pyromellitic acid dianhydride is condensated and crystallized in the trapping chamber. By means of the said apparatus, it is possible to obtain high-purity needle or powdered pyromellitic acid dianhydride crystal product continuously and effectively.
Description
The present invention relates to a kind of method that from vapour phase oxidation process is produced the reaction product gas of pyromellitic acid anhydride (all acid anhydrides) technology, captures equal acid anhydride and the passive heat wall type trap of sublimating.
All acid anhydride is a kind of organic chemical industry's intermediate, with it is that the engineering plastics, coatings additive(s), additives for plastics, caking agent etc. of raw material production have excellent electrical insulation capability, high and low temperature resistance, mechanical property etc., is widely used in numerous areas such as electromechanics, electronics, aviation.
The method of the equal acid anhydride of industrial production mainly contains two kinds, and a kind of is that liquid phase oxidation, another kind are vapour phase oxidation processes.
The technological principle of liquid phase oxidation is, the raw material durol in the liquid phase that contains acid and catalyzer with the airborne oxygen generation oxidizing reaction that feeds, generate Pyromellitic Acid, the Pyromellitic Acid equal acid anhydride of generation that further dewaters.Because the technological process flow process is long, investment is big, has the equipment corrosion problem, and must could become acid anhydride through dehydration, thereby, the production cost height, this processing method is not widely adopted.
Vapour phase oxidation process is the durol after air and the gasification to be mixed into the oxidation reactor that contains catalyzer carry out oxidizing reaction, and reaction product is after the heat exchange cooling, and all acid anhydride directly sublimates out from gas phase.Because gas-phase process is simple, not too high to the rotproofness requirement of equipment, production cost is relatively low, makes it become the main flow technology that equal in the world at present acid anhydride is produced.
In vapour phase oxidation process, the main reaction equation that the durol oxidation generates equal acid anhydride is:
When reaction generates equal acid anhydride, some side reactions taking place also, generates the by product of some parts oxidation and over oxidation, as: the carbonic acid gas of alkyl acid anhydrides, alkyl-carbonyl acid anhydrides, trimellitic acid 1,2-anhydride, phthalic anhydride, cis-butenedioic anhydride etc. and complete oxidation and water etc.Because all acid anhydride fusing point height (285 ℃), boiling point height (398～400 ℃), other by product also mostly have fusing point height, characteristics that boiling point is high, increased the difficulty of later separation part greatly.Therefore, effective Separation and Recovery of the equal acid anhydride of realization response product and other by product how becomes the key link of vapour phase oxidation process production technique.
In vapour phase oxidation process, the cooling of the reaction product gas mode of sublimating is divided into two big classes substantially, a class be reaction product gas by cooling surface and heat-eliminating medium heat exchange, the indirect method of cooling that is cooled and; Another kind of is that reaction product gas directly mixes with heat-eliminating medium, thus the direct method of cooling that gas temperature is lowered.
In indirect method of cooling, the equal acid anhydride that the at present domestic Chinese patent CN1245171A that generally adopts proposes is sublimated and captured recovery technology is a kind of indirect method of cooling technology of not controlling the cooling surface temperature of sublimating.Also need refining through technological processs such as hydrolysis, distillation or the rectification under vacuum of follow-up complexity or hot gas flow carry with the sublimate thick acid anhydride (the defective equal acid anhydride that contains by product) that obtains of this technology, impurity in the thick acid anhydride could be removed, obtain highly purified equal anhydride product.And these follow-up treating processes long flow path often, facility investment is big, and carrying capacity of environment is big, and therefore the production cost height is unsuitable for and carries out scale operation.
Utilize in the oxidation reaction product gas equal acid anhydride concentration much larger than other by-product concentration and all the saturation vapour pressure of acid anhydride be lower than the characteristics of the saturation vapour pressure of most of by products again, by the sublimate service temperature of process of control, make it be lower than the sublimating temperature of equal acid anhydride and be higher than the temperature of sublimating of other by product, thereby the single stage method that a step directly obtains the equal acid anhydride of high purity in the device of sublimating is to reclaim the Perfected process of equal acid anhydride.DE-PS.No.2362659, U.S.pat.No.4036594 and U.S.pat.No.4252545 have successively proposed indirect cooling single stage method and have sublimated and capture technology and the equipment obtain the equal acid anhydride of high purity.But these methods are difficult in industrial being generalizable, and its reason one is for controlling equal acid anhydride purity, and cooling surface need be kept higher temperature, thereby has reduced the heat transfer temperature difference of reaction product gas and cooling surface greatly, causes the significantly increase of heat transfer sheet area; The 2nd, the equal acid anhydride of crystallization on heat exchange surface is very big with online removing of simple mechanical means and collection difficulty.
The another kind of method different with indirect method of cooling is heat-eliminating medium is directly contacted with reaction product gas or to mix, thus the direct method of cooling that temperature is reduced.
Chinese patent CN 1175579 has proposed to cool off reaction product gas with water cycle, will be dissolved in equal acid anhydride in the water and other by product crystallisation by cooling then, again in the subsequent process direct method of cooling of purified of dewatering.The same with Chinese patent CN 1245171A, the thick acid of this technology gained (thick acid anhydride meet water be hydrolyzed into thick acid) also needs through dehydration, and is refining etc., and process could obtain the equal acid anhydride of high purity.
In the hot gas flow method of carrying that U.S.pat.No.3328428 proposes is purified equal anhydride process, introduced with the indirect cooling of reaction product gas or to the rare gas element that wherein directly injects the part lesser temps, as: air or water vapor, make its temperature be reduced to 100～200 ℃, then the solids crude acid anhydride that produces is carried the technological process of purification with hot gas flow.This patent has proposed to inject the part rare gas element and has carried out the direct method of cooling of refrigerative in reaction product stream, but carries purifying technique because this patent main purpose is the hot gas flow that proposes equal acid anhydride, thereby to rare the mentioning of direct refrigerative concrete grammar.
U.S.pat.No.4598157 has proposed directly to cool off with freezing air, with the exhaust combustion behind the equal acid anhydride of recovery, then waste gas after burning recirculation is returned the direct cooling of reactor---the technology that waste gas circulation is used.This technology is useful to the organic waste discharging that reduces in the tail gas, oxygen concentration reduces in the reactant gases but the circulation of waste gas makes, will inevitably have a negative impact to oxidation reaction process, in addition, this technology does not propose how to realize direct refrigerative method and apparatus yet.
U.S.pat.No.4725291 has proposed concrete grammar and the equipment that direct method of cooling captures equal acid anhydride, the trap of sublimating of this patent adopts the hollow equipment of a kind of vertical garden tubular, reaction product gas mixes slave unit top, back and enters with cold inertness gas, the equal acid anhydride needle crystal that generates falls into device bottom and is collected, by regulating the cold inertness gas volume that injects the mixed gas temperature is controlled between 150～200 ℃, the equipment wall is the chuck type, circulate by the thermal barrier in the chuck, the maintainer wall temperature is between 150～200 ℃, sublimate to prevent that impurity from cooling off on wall, the V-bar of gas in the trap of sublimating is 0.05～0.5m/S.Mean residence time is 5～60S.Though technology and equipment that this patent proposes are feasible on pilot plant, can run into problems during industrial application.At first, the jacket type structure that adopts for the maintainer wall temperature makes that people are difficult to according to the desirable processing requirement that captures of sublimating rational device structure and size are set, and have to adopt the garden cylindrical device that to bear external pressure, like this, a thermal barrier system that keeps jacket temperature just need be set, and the investment of equipment itself also will inevitably increase greatly; Secondly, the hollow equipment of garden tubular of no inner member, operational condition according to this patent proposition, after amplifying on the full scale plant, device inner fluid Reynolds number reduces, and all acid anhydride molecule or intergranular collision probability reduce, and is difficult for forming big equal acid anhydride crystal, cause and discharge all acid anhydride amount of carrying increases in the tail gas, capture the rate of recovery thereby reduce; In addition, mixing place of cold and hot gas will generate some impure solids crude acid anhydrides inevitably, and these thick acid anhydrides directly fall at the bottom of the device, will influence the quality that is stored in the equal anhydride product at the bottom of the device.
In sum, there are various defectives in traditional equal acid anhydride capture method and equipment, in industrial practice, are difficult to obtain the result who makes us very satisfied.
The objective of the invention is to propose a kind ofly to produce the reaction product gas of equal acid anhydride, high-level efficiency, directly capture sublimate capture method and the equipment that obtains the equal anhydride product of high purity economically, continuously from vapour phase oxidation process.
The present invention realizes like this, a passive heat wall type that constitutes by mixing section and dust trapping chamber trap of sublimating, directly mix at the mixing section of the trap of sublimating with cold noble gas body being cooled to a little more than the sublimate oxidation reaction product gas of temperature of equal acid anhydrides, the temperature of control mixed gas is sublimated temperature and is higher than the by product temperature of sublimating being lower than equal acid anhydride, the a small amount of impure solids crude acid anhydride that mixing process forms is settled down to the mixing section bottom and is collected, after the gas that reaches supersaturation or contain tiny equal acid anhydride solid particulate of removing partial impurities leaves mixing section, enter dust trapping chamber, with be arranged in the dust trapping chamber high surface area bench grafting of sublimating and touch, collision, all the acid anhydride crystal forms on the bed surface of sublimating, grow up, when accumulation reach a certain amount of after, under the vibration of external force, crystal comes off from bed surface; Or along with the increase of accumulation volume, when crystalline gravity during greater than the bonding force of crystal and bed surface, crystal comes off from bed surface voluntarily; Or air-flow is set at traverse baffle or baffling equipment baffling in the dust trapping chamber, causes between equal acid anhydride molecule and solid particulate collision mutually and forms bigger crystal grain, is collected at the bottom of dust trapping chamber by gravity fall.For preventing owing to the wall temperature of the trap of sublimating is low excessively, cause occurring that by product is sublimated and the product purity that influences equal acid anhydride in the wall inboard, take outside device, to add the thermal insulating warm-keeping layer with good thermo-insulation properties of adequate thickness, the heat that the interior hot gas flow of interceptor is passed to wall scatters and disappears to the external world, make wall maintain with device in gas flow temperature approaching, sublimate on the comparatively high temps of temperature but be higher than by product.With need come the hot-wall structure (we are called " initiatively hot wall ") of maintainer wall temperature different with the external heat carrier, the device structure of this " passive hot wall " can require to be provided with according to the process ideal technology of sublimating, and can directly collect the equal anhydride product of high purity of the yield that approaches to balance each other with this passive heat wall type trap of sublimating from reaction product gas.If be necessary also can in the gas after capturing equal acid anhydride, reinject cold inertness gas, further reduce gas temperature, use the same method, reclaim solid by-product.At last, reclaimed the gas of equal acid anhydride or its by product, left dust trapping chamber, entered follow-up vent gas treatment operation as tail gas.
Reaction product gas of the present invention is by heated raw material 1,2,4,5-tetraalkyl benzene or durol steam and air mixed, 350～500 ℃ of temperature, and pressure 0.1～0.3MPa (a), air speed 1000～15000h
-1, feed loading 5～50g/m
3Condition under, under the effect of solid oxide catalyst, that carries out in oxidation reactor that oxidizing reaction generates contains the equal acid anhydride of purpose product, incomplete oxidation the by product acid anhydrides or the acid of carbonyl, alkyl (as contain) over oxidation by product (as trimellitic acid 1,2-anhydride, phthalic anhydride, cis-butenedioic anhydride etc.) and complete oxidation resultant (as carbonic acid gas and water), and the mixed gas of composition such as unreacted nitrogen and oxygen in the feeding air.
Before entering the trap of sublimating, the temperature of reaction product gas preferably is cooled to a little more than equal acid anhydrides temperature of sublimating under operational condition by heat exchange.If temperature control is too high, then need to inject too much cold inertness gas, cause the rare gas element consumption to increase, also can reduce the dividing potential drop of equal acid anhydride simultaneously, be unfavorable for sublimating of equal acid anhydride; If temperature is low excessively, then all acid anhydride might sublimate out in pipeline before entering the trap of sublimating or equipment, causes flow process to stop up.When oxidizing reaction yield during at 70～120% (W), the temperature that reaction product gas enters the trap of sublimating preferably is controlled at 190～230 ℃.
Said cold inertness gas, be meant temperature be lower than equal acid anhydride sublimate temperature, no solid impurity, the gas of chemical reaction do not take place with equal acid anhydrides under the condition of sublimating, as air, nitrogen, oxygen, carbonic acid gas, steam etc.From the angle that economy is easy to get, optimal cold inertness gas is the air of room temperature.
The trap of sublimating that the present invention proposes is made of mixing section and dust trapping chamber.The major function of mixing section is that the realization response product gas mixes with the effective of cold inertness gas, and will mix the solids crude acid anhydride that contains impurity that the back generates and separate from gas, to guarantee the quality of the equal acid anhydride that dust trapping chamber generates.The residence time of mixed gas should not be oversize in the mixing section, to prevent that too much equal acid anhydride from generating big crystal and being collected at the bottom of mixing section as thick acid anhydride; But also should not be too short, to prevent mixing inequality or impurity carries, this residence time is preferably in 0.5～10S.
After the gas that reaches supersaturation or contain tiny equal acid anhydride solid particulate of removing partial impurities leaves mixing section and enters dust trapping chamber, touch, collide with the bench grafting of sublimating, all the acid anhydride crystal forms on the bed surface of sublimating and grows up, and these crystal of growing up become the brilliant bed of supersaturated gas afterwards again.The structure of bed of sublimating should have bigger surface-area, be easy to gas by and cause turbulence, the crystal that is easy to generate comes off, for example, its structure formation can be the metal or the nonmetal thing of the linear structures such as garden steel, band steel, square steel, chain, spiral-line of many rows multiple row of the planarized structure such as silk screen, expanded metals, porous plate, steel plate of or the oblique perpendicular or parallel with air flow line of many row's vertical hangings or vertical hanging.Sublimate the bed total surface area be preferably in 0～100m
2The equal acid anhydride h of/kg.
When the equal acid anhydride crystal accumulation on the bed of sublimating reached a certain amount of, dependence external force caused the bed vibration of sublimating, and crystal is split away off from bed surface, and this vibration can be continuously uniformly, also can be resting period property; Also can adopt the friction bed of sublimating, the equal acid anhydride crystalline gravity that forms when accumulation on the bed surface is during greater than crystal and bed surface or crystal and crystalline bonding force, and crystal comes off automatically.
Dust trapping chamber also can maybe can make the equipment of gas baffling itself constitute by the inner member that can make gas baffling, pass through baffling, cause turbulence, make in the supersaturated gas all collision probability increases between acid anhydride molecule and solid particulate, molecule and molecule, solid particulate and solid particulate, thereby crystallization is merged into than macrocrystal, falls under action of gravity at last and is collected.
The height of the temperature of sublimating is by equal concentration of acid anhydride in the mixed gas, the concentration of by product, and the equal anhydride product purity decision of working pressure and requirement, and control by the cold inertness gas volume that injects from mixing section.Under the same terms, the temperature of sublimating height, then equal anhydride product purity height, product yield is low; Otherwise the temperature of sublimating is low, and then all anhydride product purity is low, the product yield height.Under aforesaid oxidation reaction condition, the temperature of sublimating should be controlled at 100～200 ℃, is preferably in 130～190 ℃.
Theoretically, the residence time and the path of process of mixed gas in dust trapping chamber is long more, all the approaching more theoretical yield that balances each other of the rate of recovery of acid anhydride.But the long residence time causes facility investment to increase on the one hand, and on the other hand, excessive equipment surface heat radiation also can influence equal anhydride product quality.Therefore, according to the inventor's research practice, the total residence time of mixed gas in dust trapping chamber is preferably in 5～180S.
The flow velocity of mixed gas in dust trapping chamber also influences very big to capturing effect.Flow velocity is excessive, and the solid particulate of generation is free settling not, causes the rate of recovery to reduce, and simultaneously, system pressure drop also can increase; Flow velocity is too small, and all the probability of acid anhydride molecule or tiny equal acid anhydride particle collision reduces, and is difficult for crystallization and merges, and also can cause the rate of recovery to reduce.According to research, the optimum flow rate that mixes indoor gas is 0.1～5m/s.
Because the wall temperature of trap of sublimating is low excessively, cause the wall inboard to occur that by product is sublimated and the product purity that influences equal acid anhydride for preventing, require the wall temperature of the equipment of keeping to be higher than the temperature of sublimating of by product." initiatively hot wall " is by setting up a chuck in the equipment outside, and by the circulation of thermal barrier in the chuck, the maintainer wall temperature is sublimated more than the temperature at by product.But after adopting chuck and thermal barrier, the desirable processing requirement design that people are difficult to capture according to the sublimating trap structure of sublimating, and facility investment and process cost also increase greatly.The present inventor according to the principle of thermal conduction study, proposes the method with " passive hot wall " maintainer wall temperature by analysis and research, and the checking that obtains putting into practice.According to heat transfer principle, the heat transfer system that atmosphere conducts heat outside hot gas flow in device, wall, adiabatic heat-insulation course device, the wall temperature is mainly by gas temperature, device inwall film heat transfer coefficient, device inwall thermal resistance, wall thermal conductivity, wall thickness, thermal insulating warm-keeping layer thermal conductivity, adiabatic heat-insulation layer thickness, the outer film heat-transfer coefficient of thermal insulating warm-keeping layer and free air temperature decision in the device, in these parameters, maximum and what can hold is the thermal conductivity and the thickness of thermal insulating warm-keeping layer to wall temperature effect.Theoretically, as long as the thermal conductivity of thermal insulating warm-keeping layer is enough little or thickness is enough big, the wall temperature just can be near hot stream temperature in the device, and the temperature difference of hot gas flow will be very little in wall temperature and the device in other words.The maintainer wall temperature is different by the heat supply of external heat carrier with " initiatively hot wall ", the wall temperature of this method is heat is passed to wall and to be scattered and disappeared and keep to the external world by the outer thermal insulating warm-keeping layer trap heat of wall by the hot gas flow in the device, the wall temperature changes with the temperature variation of hot gas flow in the device, and be lower than the temperature of hot gas flow in the device forever, therefore, we claim this hot wall to be " passive hot wall ".The temperature difference of hot gas flow can not be too big in the wall temperature of " passive hot wall " and the device, otherwise by product will sublimate out, thereby influence the quality of equal anhydride product, and this temperature difference should be controlled and be not more than 10 ℃.
The structure of the best trap of sublimating is the box structure of rectangular parallelepiped, be divided into mixing section and several dust trapping chamber of bottom band collection bucket therebetween by dividing plate, be interconnected between chamber and the chamber, reaction product gas and cold inertness gas are entered by the mixing section of an end, and tail gas is discharged from the dust trapping chamber of the other end.Except the box structure of rectangular parallelepiped, the trap of sublimating also can be made up of the mixing section and the dust trapping chamber of garden tubular that is interconnected to a plurality of bottoms band collection bucket of one group.
If by product is also captured by the trap of sublimating to be reclaimed, can re-inject cold inertness gas in suitable dust trapping chamber position, further reduce gas temperature, make contain part all the by product of acid anhydride in follow-up dust trapping chamber, sublimate out equal anhydride products and by product is collected respectively and by discharging at the bottom of dust trapping chamber separately.
, to the represented embodiment of accompanying drawing-5 device structure of the present invention and principle of work are described below in conjunction with accompanying drawing-1.It is pointed out that according to the technology and equipment CONSTRUCTED SPECIFICATION among the described embodiment of the principle of the invention, just, other technology and equipment structure that forms according to the principle of the invention is not construed as limiting in order better to set forth the principle of the invention and its exploitativeness.
Accompanying drawing-1/1 and accompanying drawing the-the 1/2nd, air-flow up and down the sublimate box trap master that sublimates of bed of the band of baffling are looked and schematic top plan view.
Accompanying drawing-2/1 and accompanying drawing the-the 2/2nd, the band of flow level baffling sublimate the bed the box trap master that sublimates look and schematic top plan view.
Accompanying drawing-3/1 and accompanying drawing the-the 3/2nd, the air-flow up and down band of the baffling garden tubular of the bed trap master that sublimates that sublimates are looked and schematic top plan view.
Accompanying drawing-4/1 and accompanying drawing the-the 4/2nd, the box trap master that sublimates of the band traverse baffle of flow level baffling looks and schematic top plan view.
Accompanying drawing-5/1 and accompanying drawing the-the 5/2nd, the air-flow box trap master that sublimates of baffling are up and down looked and schematic top plan view.
In accompanying drawing-1/1,2, the box trap of sublimating of rectangular parallelepiped is separated into mixing section (2) and some dust trapping chamber (3) by dividing plate (4), last or the following barbed portion of dividing plate (4) can be interconnected each chamber, 1#～5# represents the numbering of dust trapping chamber respectively, in dust trapping chamber (3), be hung vertically under the bedstead (6) some porous plates (5) or along perpendicular to air flow line (shown in 1#, 2# dust trapping chamber), or along being diagonal to air flow line (shown in 3#, 4# dust trapping chamber), or arrange to (shown in 5# dust trapping chamber) along being parallel to air-flow gas.Heat exchange is cooled to 190～230 ℃ reaction product gas (7) and enters mixing section (2) and mix with the freezing air that enters mixing section (2) (8/1), by regulating the amount of injecting freezing air (8/1), control mixed gas temperature at 130～190 ℃, the a small amount of impure solids crude acid anhydride that forms in the mixing process is by the bottom hopper of gravity settling to mixing section (2), by the thick acid anhydride discharging of discharge port (11) conduct.The gas of removing the supersaturation of partial impurities or containing tiny equal acid anhydride solid particulate enters 1# dust trapping chamber from the bottom by the notch that dividing plate (4) forms along the direction shown in the arrow (9), in 1# dust trapping chamber, gas is bottom-up to flow, pass when sublimating bed (5), all acid anhydride is sublimated in bed and is crystallized out, and grow up gradually, after equal acid anhydride crystal is grown up and is gathered to a certain degree, by acting on bedstead (6) or sublimating the external force of bed on (5), continuously equably or resting period property ground vibration or by self gravitation, make equal acid anhydride crystal break away from bed surface, sedimentation falls in dust trapping chamber's bottom hopper, by discharge port (12) as the qualified product discharging.Leave the gas of the bed (5) of sublimating, enter 2# dust trapping chamber from the upper notch that is formed by another piece dividing plate, in 2# dust trapping chamber, except gas flowed from the top down, other process was identical with aforementioned process.Through behind the bed of sublimating of q.s, the state that reaches capacity substantially of the equal acid anhydride in the gas, in other words, the equal acid anhydride rate of recovery of trap is near reaching the Phase Equilibrium theory value.Remaining equal acid anhydride obtains reclaiming with other by product in the gas if need make, can be in position, as 4# dust trapping chamber among the figure (6# dust trapping chamber in the accompanying drawing-5) position, re-inject freezing air (8/2), so thereafter, dust trapping chamber, just repeating aforesaid process under the lower temperature of sublimating, is the solid by-product that contains equal acid anhydride from bottom discharge mouth (13) discharging just.The tail gas that is captured out most of all acid anhydrides or by product by sublimating is discharged from tail gas outlet (10), enters follow-up vent gas treatment operation.
In accompanying drawing-2/1,2, except gas flow direction is horizontal baffling, other process and accompanying drawing-1/1,2 similar.
In accompanying drawing-3/1,2, mixing section (2) and dust trapping chamber (3) by separately independently bottom band collection bucket, in establish the bed (5) of sublimating the garden cylindrical device constitute, the pipeline (14) of baffling is communicated with by forming up and down each other, other process and accompanying drawing-1/1,2 similar.
In accompanying drawing-4/1,2, with accompanying drawing-2/1,2 different be, the inner member of dust trapping chamber is not the bed of sublimating, but constitute by the some traverse baffles that stagger mutually (15) that can cause gas baffling perpendicular to air-flow, supersaturation or the gas that contains tiny equal acid anhydride solid particulate in dust trapping chamber by horizontal baffling, collision mutually, the result generates bigger crystal, by gravity fall to bottom hopper, other process and accompanying drawing-2/1,2 similar.
Accompanying drawing-5/1,2 is actually by mixing section with not with the trap of sublimating of the baffling up and down that constitutes of dust trapping chamber of the bed of sublimating, be with accompanying drawing-4/1,2 difference, the direction of gas baffling be about baffling, other process and accompanying drawing-4/1,2 similar.
Claims (11)
1. one kind is applicable to produce directly to sublimate the reaction product gas that equal anhydride process process produces from the durol vapour phase oxidation process and captures the method that obtains equal anhydride product of high purity or by product and the passive heat wall type trap of sublimating, it is characterized in that: adopt cold inertness gas and heat exchange to be cooled to and mix a little more than the sublimate reaction product gas of temperature of equal acid anhydride, mixed gas directly is cooled to the temperature of sublimating that is lower than equal acid anhydride, but be higher than in the temperature range of the temperature of sublimating of by product, make equal acid anhydride reach hypersaturated state, sublimate bed or the baffling structure that is provided with in the trap of sublimating provides crystallization condition for the equal acid anhydride gas of supersaturation, equal acid anhydride is separated from mixed gas, for prevent that the by product crystallization of sublimating from influencing the equal acid anhydride purity of product on wall, adopt the passive heat wall construction, the maintainer wall temperature approaches the temperature of gas in the device, in this way, can directly capture continuously and obtain needle-like or the equal acid anhydride crystal of powdered, the passive heat wall type that forms according to this method trap of sublimating, constitute by mixing section (2) and dust trapping chamber (3), be provided with bed (5) or the traverse baffle (15) or itself be the equipment that can cause baffling of sublimating in the dust trapping chamber (3), the wall temperature adopts passive hot wall to keep, heat exchange is cooled to 190 ℃～230 ℃ reaction product gas and mixes with cold inertness gas in mixing section (2), make mixed gas temperature be controlled at 130 ℃～190 ℃, the a small amount of impure solids crude acid anhydride that generates in the mixing process is by mixing section bottom discharge mouth (11) discharging, after the gas of removing the supersaturation of partial impurities or containing tiny equal acid anhydride solid particulate enters dust trapping chamber (3) from mixing section (2), equal acid anhydride wherein is in the bed of the sublimating crystallization of sublimating on (5), when accumulation reach a certain amount of after, the vibration of outer power, crystal is come off from bed surface, or lean on gravity to come off from bed surface voluntarily, or gas is by baffling, equal acid anhydride molecule wherein or fine particle collision form big crystal grain, lean on gravity fall to dust trapping chamber's bottom discharge mouth (12) discharging then, also can use the same method, in the gas that has reclaimed equal acid anhydride, re-inject cold inertness gas, further reduce gas temperature, by product is sublimated, can obtain solid by-product in follow-up dust trapping chamber.
2. the passive heat wall type according to claim 1 trap of sublimating is characterized in that: heat that the wall temperature is provided to wall by internal gas and the heat insulation of thermal insulating warm-keeping layer that is located at the wall outside are kept.
3. wall temperature according to claim 2 is characterized in that: the temperature difference of gas is not more than 10 ℃ in wall temperature and the device.
4. method according to claim 1 is characterized in that: cold inertness gas is: air, nitrogen, oxygen, carbonic acid gas, steam.
5. cold inertness gas according to claim 4 is characterized in that: cold inertness gas is the air of room temperature.
6. the passive heat wall type according to claim 1 trap of sublimating is characterized in that: its structure be rectangular parallelepiped box, by dividing plate (4) casing is divided into the mixing section (2) of the bottom band collection bucket that is interconnected and the equipment of several dust trapping chamber (3).
7. the passive heat wall type according to claim 1 trap of sublimating is characterized in that: its structure serve as reasons garden tubular mixing section (2) and several dust trapping chamber with spline structure (3) of bottom band collection bucket, the equipment that is connected as a single entity by pipeline (14).
8. the passive heat wall type according to claim 1 trap of sublimating is characterized in that: bed (5) structure formation of sublimating be the porous plate of or the oblique perpendicular or parallel of many row's vertical hangings, dull and stereotyped silk screen, expanded metals with air flow line, etc. planarized structure or arrange the metal or the nonmetal thing of the linear structures such as garden steel, band steel, square steel, chain, zigzag shape of multiple row vertical hanging more.
9. the bed (5) of sublimating according to claim 8 is characterized in that: the surface-area of the bed of sublimating is 0～100m
2The equal acid anhydride h of/kg.
10. the passive heat wall type according to claim 1 trap of sublimating, it is characterized in that: the residence time of gas in mixing section (2) is 0.5～10s.
The trap 11. passive heat wall type according to claim 1 is sublimated is characterized in that: the total residence time of gas in all dust trapping chamber is 5～180s.
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| CNB011193239A CN1193030C (en) | 2001-05-29 | 2001-05-29 | Pyromellitic acid dianhydride trapping method and apparatus |
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| CNB011193239A CN1193030C (en) | 2001-05-29 | 2001-05-29 | Pyromellitic acid dianhydride trapping method and apparatus |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102070519A (en) * | 2010-12-06 | 2011-05-25 | 横店集团东阳英洛华绿色电化学有限公司 | Method for purifying 3,4,5,6-tetrachloro-2-cyanopyridine by sublimation and catching, and catcher and system thereof |
| CN102336761A (en) * | 2010-12-17 | 2012-02-01 | 常熟市联邦化工有限公司 | Method for capturing and purifying pyromellitic dianhydride |
| CN105948827A (en) * | 2016-04-26 | 2016-09-21 | 郭伟 | Chelating urea produced from pyromellitic dianhydride process waste residue and production method thereof |
| CN106748702A (en) * | 2017-01-17 | 2017-05-31 | 湖北开元化工科技股份有限公司 | The equipment that a kind of sublimed method produces 1,4-benzoquinone |
| CN106925081A (en) * | 2017-05-10 | 2017-07-07 | 泰兴协联众达化学有限公司 | Production liquid phthalic anhydride entrucking gas concentration unit and its operating method |
| CN113354654A (en) * | 2021-07-14 | 2021-09-07 | 江苏信泰化工装备有限公司 | Trapping and recovering device |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100453544C (en) * | 2005-09-14 | 2009-01-21 | 浙江大学 | Method for separating gas phase pyromellitic dianhydride from mixed gas |
-
2001
- 2001-05-29 CN CNB011193239A patent/CN1193030C/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102070519A (en) * | 2010-12-06 | 2011-05-25 | 横店集团东阳英洛华绿色电化学有限公司 | Method for purifying 3,4,5,6-tetrachloro-2-cyanopyridine by sublimation and catching, and catcher and system thereof |
| CN102070519B (en) * | 2010-12-06 | 2012-10-10 | 横店集团东阳英洛华绿色电化学有限公司 | Method for purifying 3,4,5,6-tetrachloro-2-cyanopyridine by sublimation and catching, and catcher and system thereof |
| CN102336761A (en) * | 2010-12-17 | 2012-02-01 | 常熟市联邦化工有限公司 | Method for capturing and purifying pyromellitic dianhydride |
| CN105948827A (en) * | 2016-04-26 | 2016-09-21 | 郭伟 | Chelating urea produced from pyromellitic dianhydride process waste residue and production method thereof |
| CN105948827B (en) * | 2016-04-26 | 2019-07-30 | 郭伟 | Utilize the chelating urea and production method of the production of pyromellitic acid anhydride technique waste residue |
| CN106748702A (en) * | 2017-01-17 | 2017-05-31 | 湖北开元化工科技股份有限公司 | The equipment that a kind of sublimed method produces 1,4-benzoquinone |
| CN106748702B (en) * | 2017-01-17 | 2023-09-01 | 湖北开元化工科技股份有限公司 | Equipment for producing p-benzoquinone by sublimation method |
| CN106925081A (en) * | 2017-05-10 | 2017-07-07 | 泰兴协联众达化学有限公司 | Production liquid phthalic anhydride entrucking gas concentration unit and its operating method |
| CN113354654A (en) * | 2021-07-14 | 2021-09-07 | 江苏信泰化工装备有限公司 | Trapping and recovering device |
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| Publication number | Publication date |
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| CN1193030C (en) | 2005-03-16 |
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