Trimellitic acid becomes the method for acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously
Technical field
The present invention relates to the method that a kind of trimellitic acid becomes acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously.Belong to field of chemical technology.
Background technology
Trimellitic acid 1,2-anhydride is the important Organic Chemicals of modern type material, and very high reactive behavior is arranged, and can generate a series of fine chemicals that high added value is arranged, and is mainly used in industries such as engineering plastics, high-quality softening agent, heatproof insullac, high grade paint.Owing to have excellent electrical insulating property, resistance to elevated temperatures and mechanical property with its made resin material, also be widely used in industrial circles such as electromechanics, electronics and space flight.
At present, trimellitic acid 1,2-anhydride purified method mainly adopts intermittent type to become acid anhydride method for refining technology, be about to trimellitic acid and solvent material that oxidation generates, directly add in the crystallization kettle in batches, the water that elder generation's heating evaporation solvent acetic acid and oxidizing reaction generate, intramolecularly a part water is deviate from intensification again, makes the trimellitic acid 1,2-anhydride crude product.The crude product trimellitic acid 1,2-anhydride adopts fixedly tube still heater intermittent fractionation technology: the crude product trimellitic acid 1,2-anhydride is put in batches and is carried out rectification under vacuum in first rectifying tower, the material that steams enters second rectifying tower (or the 3rd rectifying tower) again and carries out secondary (or three times) rectifying, finally obtains the trimellitic acid 1,2-anhydride finished product.This method has the following disadvantages:
1, poor product quality, quality instability, material decompose serious.
2, in the batch production process, reactor needs repeatedly voltage raising and reducing, heats up and lower the temperature, and equipment is tired easily and produce leakage, and shorten work-ing life.
3, heating evaporation formula deacidifying process is adopted in the interrupter method crystallization, and acetic acid and water are steamed, and catalyzer such as cobalt, manganese are trapped in the trimellitic acid 1,2-anhydride crude product, have both increased the consumption of catalyzer, have also increased the decomposition of trimellitic acid 1,2-anhydride in subsequent handling.
Chinese patent application CN1401642A disclosed " the continuous processing oxidizing process is produced the method for trimellitic acid 1,2-anhydride ", Chinese patent application CN1594302A disclosed " a kind of method of the continuous production of catalyzed oxidation step by step trimellitic acid 1,2-anhydride ", Chinese patent application CN1634907A disclosed " method of stirring type multi-kettle continuous oxidation preparation of trimellitic anhydride ", they and present method are the continuous oxidation style of unsym-trimethyl benzene liquid-phase catalysis, generate trimellitic acid earlier, be dehydrated into the refining trimellitic acid 1,2-anhydride production method of producing of acid anhydride again.The crude product trimellitic acid 1,2-anhydride is made with extra care and is single tower intermittent type or continous way rectifying in the above method, because the impure complexity of trimellitic acid 1,2-anhydride crude product, only once simple rectifying can not produce high purity product, want to guarantee quality product, must many extraction light, heavy constituent and carry out repeatedly rectifying cause purified material consumption energy consumption to increase.
Summary of the invention
The objective of the invention is to overcome above-mentioned deficiency, the method that provide that a kind of material consumption energy consumption is low, product purity is high, steady quality, trimellitic acid that yield is high becomes acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously.
The object of the present invention is achieved like this: a kind of trimellitic acid becomes the method for acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously, it is characterized in that this method comprises following processing step:
Step 1, depickling, dehydration, one-tenth acid anhydride
Trimellitic acid particle wet stock is dropped into the 1# kettle continuously, the control temperature in the kettle is at 120 ℃~250 ℃, pressure is 0.05MPa~0.15MPa, trimellitic acid particle wet stock is melt into liquid state in kettle, and remove remaining acetic acid and the water that brings in the particle wet stock, the acetic acid that steams removes the acetic acid upgrading system with water vapor after becoming the acid anhydride condenser condenses, trimellitic acid after the dehydration enters the 2# kettle, continue to take off intramolecularly a part water, temperature is at 140 ℃~260 ℃ in the control 2# kettle, pressure is 0.05MPa~0.15Mpa, and the crude product trimellitic acid 1,2-anhydride that obtains removes the crude product jar;
Step 2, take off heavy constituent
Heavy constituent vapor jet pump group is taken off in operation, vacuumize to taking off the heavy constituent system, keep system pressure≤5mmHg, the crude product trimellitic acid 1,2-anhydride sent into continuously take off reevaporator, high boiling substance in the crude product trimellitic acid 1,2-anhydride is isolated system in the residue mode enter residual liquid tank, 160 ℃~250 ℃ of temperature are taken off in the reevaporator in control, and pressure≤5mmHg takes off in the reevaporator gas and takes off heavy jar through taking off to enter after the heavy condenser condenses;
Step 3, take off light constituent
Light constituent vapor jet pump group is taken off in operation, vacuumize to taking off the light constituent system, keep system pressure≤10mmHg, will take off heavy jar of interior material and send into lightness-removing column, through taking off light vaporizer film-type evaporation, material steam carries out mass-and heat-transfer in filler, light constituent captures partial material through trap, and temperature is 160 ℃~220 ℃ in the control lightness-removing column, pressure≤10mmHg, material utilizes recycle pump to send into rectifying tower in the tower, by lightness-removing column liquid level control rectifying tower feed rate;
Four, rectifying
Operation rectifying vapor jet pump group, vacuumize to distillation system, keep system pressure≤5mmHg, through rectifying vaporizer film-type evaporation and gas-liquid mass-and heat-transfer in filler, the high trimellitic acid 1,2-anhydride component of content is condensed under the overhead condenser effect, enters trimellitic acid 1,2-anhydride finished product jar by rectifying tower middle and upper part extraction mouth, and temperature is 200 ℃~240 ℃ in the control rectifying tower, pressure≤5mmHg, liquid trimellitic acid 1,2-anhydride finished product is through knot sheet operation slice packaging product.
Trimellitic acid of the present invention becomes the method for acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously, and described 1# kettle adopts the rotary drum vaporizer.
Trimellitic acid of the present invention becomes the method for acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously, and the described reevaporator that takes off is scraped film evaporator or rotary drum vaporizer.
Trimellitic acid of the present invention becomes the method for acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously, and described to take off light vaporizer be falling film evaporator, and material in the lightness-removing column tower still is sent into falling film evaporator by recycle pump, liquid level 50%~70% in the control tower.
Trimellitic acid of the present invention becomes the method for acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously, trap has many, when system vacuum has obvious decline, shows that a trap material captures to finish, switch to another trap, simultaneously material in the trap that switches is put into residual liquid tank.
Trimellitic acid of the present invention becomes the method for acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously, and taking off light vaporizer is the rotary drum vaporizer, liquid level 50%~70% in the control rotary drum vaporizer.
Trimellitic acid of the present invention becomes the method for acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously, and the rectifying vaporizer is a falling film evaporator, and material in the rectifying Tata still is sent into falling film evaporator by recycle pump, liquid level 50%~70% in the control tower.
Trimellitic acid of the present invention becomes the method for acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously, and described rectifying vaporizer is the rotary drum vaporizer, liquid level 50%~70% in the control rotary drum vaporizer.
Trimellitic acid of the present invention becomes the method for acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously, after distillation system moves for some time continuously, the finished product look number has obvious ascendant trend, show that the carbonizing matter accumulation is more in the rectifying tower still material, utilize the rectifying tower recycle pump that tower still material is all got to trimellitic acid 1,2-anhydride crude product jar, recycle.
The present invention embodies many-sided advantage, and the three-stage distillation of employing takes different temperature and pressures to handle at the different components of material respectively, fully saves heat energy; Film-type evaporation helps material and effectively separates at a lower temperature, reduces the decomposition and the coking of material under the high temperature; Stable equipment operation is reliable, and technic index is stable, is easy to control, substantially for moving under constant temperature, the constant voltage, has avoided in the batch purification technology lifting temperature and pressure repeatedly, makes easily shortcoming such as leakage of system, and device can move safely and reliably; This technological design is reasonable, can successfully manage power failure, cut off the water, stops the supple of gas or steam, stops emergency case such as thermal source.Because this continuous process flow process makes every technic index meet the separation optimizing, device is in optimal operational condition, the production intensity height, and single covering device throughput is greatly improved, and is suitable for large-scale production.Characteristics such as this technology has stable production process safety, and number low and energy consumption of constant product quality, product purity height, recovery rate height, chroma stability, look low.
The present invention becomes in the anhydridization process, and the 1# kettle adopts drum heater, helps the fusion of solid particulate wet stock material even heating, and the little negative pressure control of system helps removing of acetic acid and water.Take off heavy constituent in the refining step and adopt scraped film evaporator, scraped film evaporator has that turndown ratio is big, the treatment time is short, with the little characteristics of system vacuum pressure reduction, the ability that low-temperature evaporation is handled be can under extra-high vacuum, carry out, the decomposition and the coking of trimellitic acid 1,2-anhydride avoided as much as possible.Take off light constituent and rectification working process and adopt falling film evaporator.Because liquid film type evaporation heat transfer resistance is little, heat transfer temperature difference is low, has reduced trimellitic acid 1,2-anhydride generation temperature-sensitive Decomposition as much as possible.More than these vaporizers have: the 1. effective steam output height of unit surface, film-type evaporator thermo-efficiency is 2~4 times of common tube still heater under the same evaporation area; 2. finish same separation task, reduced vaporization temperature; 3. reduce the material to be processed carbonization and reduce product look number; 4. improve the quality and the purified recovery rate of product greatly.
The present invention adopts the refining technology of producing trimellitic acid 1,2-anhydride of continuous one-tenth acid anhydride, and product purity height, steady quality, yield height, material consumption energy consumption all make moderate progress, and list the contrast table of two kinds of methods below.
Table 1: the present invention and the contrast of batch production method quality product
Quality index | The multitower continuous process | Existing discontinuous method |
Inclined to one side acid anhydride content % | ≥99.5 | 95~98 |
Acid anhydride fusing point ℃ partially | ≥167 | 162~165 |
Colourity | ≤50# | 90#~170# |
Quality stability | Stable | Unstable |
Table 2: the present invention and existing production method unit product consumption contrast
Project | Continuous process | Existing discontinuous method |
Trimellitic acid (ton/ton product) | 1.15~1.21 | 1.28~1.57 |
Coal (ton/ton product) | 1.5~2.0 | 3~6 |
Electricity (kilowatt-hour/ton product) | ≤200 | 200 |
Product yield % (mol/mol) | 90~95 | 70~85 |
The present invention is in conjunction with the continuous oxidation production technique of our company, and the contrast table that is oxidized to acid anhydride process for purification and batch process is continuously listed in the set of gaining the upper hand on the whole below.
Table 3: the present invention is oxidized to acid anhydride process for purification and batch production method unit product consumption contrast continuously
Project | Whole continuous process | Existing discontinuous method |
Unsym-trimethyl benzene (ton/ton product) | 0.74~0.80 | 0.95~1.05 |
Acetic acid (ton/ton product) | 0.1~0.2 | 0.3~0.4 |
Cobaltous diacetate (kilogram/ton product) | 2.0~5.0 | 6.0~10 |
Manganese acetate (kilogram/ton product) | 2.0~5.0 | 6.0~10 |
Tetrabromoethane (kilogram/ton product) | 2.0~6.0 | 6.0~10 |
Coal (ton/ton product) | 2~3 | 4~8 |
Electricity (kilowatt-hour/ton product) | ≤1100 | 1500~2300 |
Produce steam (ton/ton product) | 4~5(0.4~0.5MPa) | 0 |
Product yield % (mol/mol) | 80~85 | 50~65 |
Description of drawings
Fig. 1 is a technical process block diagram of the present invention.
Among the figure: become acid anhydride condenser 1 and 2,1 # kettle 3,2# kettle 4, trimellitic acid 1,2-anhydride crude product jar 5, take off heavy fresh feed pump 6, take off reevaporator 7, residual liquid tank 8, take off heavy condenser 9 and 10, take off heavy jar 11, trap 12 and 13, lightness-removing column charge pump 14, lightness-removing column 15, take off light vaporizer 16, recycle pump 17, rectifying tower 18, rectifying vaporizer 19, recycle pump 20, trimellitic acid 1,2-anhydride finished product jar 21, rectifying vapor jet pump group 22, take off light constituent vapor jet pump group 23, take off heavy constituent vapor jet pump group 24.
Embodiment
Embodiment 1:
Embodiment 1 is the method that trimellitic acid of the present invention becomes acid anhydride refined raw production of high purity trimellitic acid 1,2-anhydride continuously, specifically comprises following processing step:
One, depickling, dehydration, one-tenth acid anhydride
10000Kg drops into 1# kettle 3 continuously with trimellitic acid particle wet stock, when liquid level reaches 60% in the 1# kettle, stop charging, opening heating unit heats up, when temperature in the kettle go back up to 〉=120 ℃ the time, start the kettle whipping appts, continuation is continuous charging in kettle, the control temperature in the kettle is at 120 ℃~250 ℃, pressure is 0.05MPa~0.15MPa, trimellitic acid particle wet stock is melt into liquid state in kettle, and removes remaining acetic acid and the water that brings in the particle wet stock.Trimellitic acid after the dehydration enters 2# kettle 4, continues to take off intramolecularly a part water, the acetic acid and the water 1775Kg that steam and deviate from, and steam removes the acetic acid upgrading system after becoming acid anhydride condenser 1 and 2 condensations.The control temperature in the kettle is at 140 ℃~260 ℃, and pressure is 0.05MPa~0.15Mpa, and the crude product trimellitic acid 1,2-anhydride that obtains removes trimellitic acid 1,2-anhydride crude product jar 5.
Two, take off heavy constituent
Heavy constituent vapor jet pump group 24 is taken off in operation, vacuumizes to taking off the heavy constituent system, keeps system pressure≤5mmHg.Open and take off heavy fresh feed pump 6, the crude product trimellitic acid 1,2-anhydride is sent into luwa evaporator 7 continuously, open luwa evaporator simultaneously, high boiling point materials such as the catalyzer in the crude product trimellitic acid 1,2-anhydride, carbonizing matter are isolated system in the residue mode enter residual liquid tank 8.Temperature is 200 ℃~220 ℃ in the control luwa evaporator 7, pressure≤5mmHg.Gases take off heavy jar 11 through taking off to enter after heavy condenser 9 and 10 condensations in the luwa evaporator 7.
Three, take off light constituent
Light constituent vapor jet pump group 23 is taken off in operation, vacuumizes to taking off the light constituent system, keeps system pressure≤10mmHg.Open lightness-removing column charge pump 14, will take off heavy jar 11 interior material and send into lightness-removing column 15.When liquid level reaches 50%~60% in the tower, open recycle pump 17, material is sent into falling film evaporator 16.Through film-type evaporation, material steam carries out mass-and heat-transfer in filler, and light constituent captures partial material through trap 12 and 13.When system vacuum has obvious decline, show that this trap material captures to finish, need switch to another trap, simultaneously material in the trap that switches is put into residual liquid tank 8.Temperature is 160 ℃~220 ℃ in the control lightness-removing column 15, liquid level 50%~70% in the pressure≤10mmHg, tower.Material utilizes recycle pump 17 to send into rectifying tower 18 in the tower, by lightness-removing column 15 liquid levels control rectifying tower 18 feed rates.
Four, rectifying
Operation rectifying vapor jet pump group 22 vacuumizes to distillation system, keeps system pressure≤5mmHg.When liquid level reaches 50% in the rectifying tower 18, open rectifying tower recycle pump 20, material is sent into falling film evaporator 19.Through film-type evaporation and gas-liquid mass-and heat-transfer in filler, the high trimellitic acid 1,2-anhydride component of content is condensed under the overhead condenser effect, enters trimellitic acid 1,2-anhydride finished product jar 21 by rectifying tower middle and upper part extraction mouth.Temperature is 200 ℃~240 ℃ in the control rectifying tower 18, pressure≤5mmHg, liquid level 50~70% in the tower, after refining system moves for some time continuously, the finished product look number has obvious ascendant trend, shows that carbonizing matter is more in the rectifying tower material, utilizes rectifying tower recycle pump 20 that tower still material is all got to trimellitic acid 1,2-anhydride crude product jar 5 and recycles, liquid trimellitic acid 1,2-anhydride finished product is through knot sheet operation slice packaging product 7485Kg, and the molar yield of product treatment is 91%.
Embodiment 2:
One, depickling, dehydration, one-tenth acid anhydride
15000Kg drops into 1# kettle 3 continuously with trimellitic acid particle wet stock, when liquid level reaches 60% in the kettle, stop charging, open heating unit and heat up, when temperature in the kettle go back up to 〉=120 ℃ the time, start the kettle whipping appts, continuation is continuous charging in kettle, and the control temperature in the kettle is at 160 ℃~240 ℃, and pressure is 0.05MPa~0.15MPa, trimellitic acid particle wet stock is melt into liquid state in kettle, and removes remaining acetic acid and the water that brings in the particle wet stock.Trimellitic acid after the dehydration enters 2# kettle 4, continues to take off intramolecularly a part water, the acetic acid and the water 2660Kg that steam and deviate from, and steam removes the acetic acid upgrading system after becoming 1,2 condensations of acid anhydride condenser.The control temperature in the kettle is at 160 ℃~250 ℃, and pressure is 0.05MPa~0.15Mpa, and the crude product trimellitic acid 1,2-anhydride that obtains removes trimellitic acid 1,2-anhydride crude product jar 5.
Two, take off heavy constituent
Heavy constituent vapor jet pump group 24 is taken off in operation, vacuumizes to taking off the heavy constituent system, keeps system pressure≤5mmHg.Open and take off heavy fresh feed pump 6, the crude product trimellitic acid 1,2-anhydride is sent into rotary drum vaporizer 7 continuously, open the rotary drum vaporizer simultaneously, high boiling point materials such as the catalyzer in the crude product trimellitic acid 1,2-anhydride, carbonizing matter are isolated system in the residue mode enter residual liquid tank 8.Temperature is 200 ℃~245 ℃ in the rotary drum vaporizer 7, pressure≤5mmHg.Gases take off heavy jar 11 through taking off to enter after heavy condenser 9,10 condensations in the rotary drum vaporizer 7.
Three, take off light constituent
Light constituent vapor jet pump group 23 is taken off in operation, vacuumizes to taking off the light constituent system, keeps system pressure≤10mmHg.Open lightness-removing column charge pump 14, will take off heavy jar 11 interior material and send into lightness-removing column 15.Material is sent into rotary drum vaporizer 16.Through film-type evaporation, material steam carries out mass-and heat-transfer in filler, and light constituent captures partial material through trap 12.Temperature is 170 ℃~220 ℃ in the control lightness-removing column 15, liquid level 50%~70% in the pressure≤10mmHg, rotary drum vaporizer.Material utilizes recycle pump 17 to send into rectifying tower 18 in the tower, by lightness-removing column 15 liquid levels control rectifying tower 18 feed rates.
Four, rectifying
Operation rectifying vapor jet pump group 22 vacuumizes to distillation system, keeps system pressure≤5mmHg.Material is sent into rotary drum vaporizer 19.Through the gentle liquid of pervaporation mass-and heat-transfer in filler, the high trimellitic acid 1,2-anhydride component of content is condensed under the overhead condenser effect, enters trimellitic acid 1,2-anhydride finished product jar 21 by rectifying tower middle and upper part extraction mouth.Temperature is 200 ℃~235 ℃ in the control rectifying tower 18, pressure≤5mmHg, liquid level 50~70% in the rotary drum vaporizer 19; After refining system moves for some time continuously, the finished product look number has obvious ascendant trend, show that carbonizing matter is more in the rectifying tower material, utilizing rectifying tower recycle pump 20 that tower still material is all got to trimellitic acid 1,2-anhydride crude product jar 5 recycles, liquid trimellitic acid 1,2-anhydride finished product is through knot sheet operation slice packaging product 11475Kg, and the molar yield of product treatment is 93%.
Embodiment 3:
One, depickling, dehydration, one-tenth acid anhydride
20000Kg drops into 1# kettle 3 continuously with trimellitic acid particle wet stock, when liquid level reaches 60% in the still, stop charging, open heating unit and heat up, when temperature in the kettle go back up to 〉=120 ℃ the time, start the kettle whipping appts, continuation is continuous charging in still, and the control temperature in the kettle is at 180 ℃~230 ℃, and pressure is 0.05MPa~0.15MPa, trimellitic acid particle wet stock is melt into liquid state in the 1# kettle, and removes remaining acetic acid and the water that brings in the particle wet stock.Trimellitic acid after the dehydration enters 2# kettle 4, continues to take off intramolecularly a part water, the acetic acid and the water 3550Kg that steam and deviate from, and steam removes the acetic acid upgrading system after becoming 1,2 condensations of acid anhydride condenser.The control temperature in the kettle is at 180 ℃~230 ℃, and pressure is 0.05MPa~0.15Mpa, and the crude product trimellitic acid 1,2-anhydride that obtains removes trimellitic acid 1,2-anhydride crude product jar 5.
Two, take off heavy constituent
Heavy constituent vapor jet pump group 24 is taken off in operation, vacuumizes to taking off the heavy constituent system, keeps system pressure≤5mmHg.Open and take off heavy fresh feed pump 6, the crude product trimellitic acid 1,2-anhydride is sent into luwa evaporator 7 continuously, open luwa evaporator simultaneously, high boiling point materials such as the catalyzer in the crude product trimellitic acid 1,2-anhydride, carbonizing matter are isolated system in the residue mode enter residual liquid tank 8.Temperature is 185 ℃~240 ℃ in the control luwa evaporator 7, pressure≤5mmHg.Gases take off heavy jar 11 through taking off to enter after heavy condenser 9,10 condensations in the luwa evaporator 7.
Three, take off light constituent
Light constituent vapor jet pump group 23 is taken off in operation, vacuumizes to taking off the light constituent system, keeps system pressure≤10mmHg.Open lightness-removing column charge pump 14, will take off heavy jar 11 interior material and send into lightness-removing column 15.When liquid level reaches 50%~60% in the tower, open recycle pump 17, material is sent into falling-film evaporator 16.Through film-type evaporation, material steam carries out mass-and heat-transfer in filler, and light constituent captures partial material through trap 12,13.When system vacuum has obvious decline, show that this trap material captures to finish, need switch to another trap, simultaneously material in the trap that switches is put into residual liquid tank 8.Temperature is 170 ℃~210 ℃ in the control lightness-removing column 15, liquid level 50%~70% in the pressure≤10mmHg, tower.Material utilizes recycle pump 17 to send into rectifying tower 18 in the tower, by lightness-removing column 15 liquid levels control rectifying tower 18 feed rates.
Four, rectifying
Operation rectifying vapor jet pump group 22 vacuumizes to distillation system, keeps system pressure≤5mmHg.When liquid level reaches 50% in the rectifying tower 18, open rectifying tower recycle pump 20, material is sent into falling-film evaporator 19.Through film-type evaporation and gas-liquid mass-and heat-transfer in filler, the high trimellitic acid 1,2-anhydride component of content is condensed under the overhead condenser effect, enters trimellitic acid 1,2-anhydride finished product jar 21 by rectifying tower middle and upper part extraction mouth.Temperature is 210 ℃~235 ℃ in the control rectifying tower 18, liquid level 50~70% in the vacuum≤5mmHg, tower; After refining system moves for some time continuously, the finished product look number has obvious ascendant trend, show that carbonizing matter is more in the rectifying tower material, utilizing rectifying tower recycle pump 20 that tower still material is all got to trimellitic acid 1,2-anhydride crude product jar 5 recycles, liquid trimellitic acid 1,2-anhydride finished product is through knot sheet operation slice packaging product 15630Kg, and the molar yield of product treatment is 94.9%.