CN101735045B - Method for producing ethyl acetate by using entrainer - Google Patents

Abstract

The invention discloses a method for producing ethyl acetate by using an entrainer. The method comprises the following steps: the entrainer and concentrated sulfuric acid used as a catalyst are added into an esterification kettle at one time, and supplemented intermittently; when acetic acid and ethanol used as raw materials are processed by a side line stream heat exchanger, a preheater, an esterification reboiler, the esterification kettle, a gas-liquid separator, an esterification column, a condenser and a phase separator, the mixed liquor obtained from the side stream of the esterification column exchanges heat with the raw materials and enters a cooler to be cooled to 40 DEG C, all or part of the organic phase ( mainly containing the entrainer) obtained from the phase separator by phase separation returns to the circulating water entrainment of the esterification column, and the ethyl acetate is obtained from the kettle of the stripping tower, wherein the entrainer is isobutyl propionate, propyl isobutyrate, or the mixture of isobutyl propionate and propyl isobutyrate. In the method for producing ethyl acetate by using an entrainer, the entrainer has the advantages of large water entrainment quantity, small use amount and capability of cyclic utilization, thereby reducing the energy consumption and material consumption in the production process, expanding the production capacity and being beneficial to the improvement of the industrial production technology.

Description

A kind of method of using entrainment agent production ethyl acetate

Technical field

The present invention relates to a kind of production method of ethyl acetate, particularly a kind of method of using entrainment agent production ethyl acetate.

Background technology

China's industrial energy consumption accounts for more than 50% of whole society's total energy consumption, and the energy consumption of unit product level of many energy-intensive commercial runs is higher by approximately 30～90% than international most advanced level.Ethyl acetate is important Chemical Solvents and basic organic chemical industry raw material, is widely used in extraction agent, perfume base of the products such as industrial solvent, tackiness agent, production medicine, organic acid etc.The production of acetic ester equal solvent be mainly react, the hot procedure such as separation is main high energy consumption, high material-consumption process industrial.China's ethyl acetate existing apparatus production technology rests on traditional liquid phase esterification process technique mostly, seldom consider the energy synthesis optimization design of device, particularly the energy-saving and cost-reducing transformation of the production technique of core not yet given enough attention, the ubiquity small scale, energy consumption is high, benefit is low, the market competitiveness is poor, be difficult to solve the problems such as corrosion and environmental pollution.Tradition production of ethyl technique is esterification-concentrate-refining-waste water reclamation four-column process flow, the phase-splitting of esterification tower top azeotrope produces the heavy phase (being water) that is rich in the light phase (being thick ester) of ester and is rich in water, thick ester moiety passes back into esterification column, the part extraction enters concentration tower and further removes and enter treating tower after alcohol, water and remove Determining Micro Acid, from treating tower tower top output ethyl acetate product, the water that esterification column tower top, concentration tower tower top produce enters the waste water reclamation tower and reclaims the light constituents such as wherein ester, alcohol.Tradition production of ethyl technique bottleneck is that the core process process intensifications such as esterification and rectifying separation are not enough, in the binary azeotrope that ethyl acetate and water form, both mol ratio is not mated with the ratio of esterification generation, a large amount of byproduct of reaction hydropexiss are in reaction system, having restricted esterification carries out to positive dirction, and need a large amount of thick esters to reflux as entrainment agent to carry the water of enrichment in system secretly, cause the esterification column reflux ratio large, energy consumption is high, has greatly limited plant capacity.

Summary of the invention

The objective of the invention is the deficiency that exists in existing Technology, the method for the use entrainment agent production ethyl acetate that a kind of energy consumption is little, yield is high is provided.

The objective of the invention is to be achieved by the following technical programs:

The method of production ethyl acetate of the present invention raw material used is comprised of ethanol, acetic acid.Each component is counted according to molar content: ethanol 40～60%, acetic acid 40～60%.Entrainment agent is isobutyl propionate, propyl isobutyrate or its mixture.Entrainment agent is disposable to add, and inlet amount is 3～8wt% of esterifying kettle still material, and owing to can losing a small amount of entrainment agent in the waste water of discharging, needing intermittently, trace replenishes.

the present invention uses the method for entrainment agent production ethyl acetate as follows: raw acetic acid, ethanol is through the side line interchanger, preheater, the esterification reboiler, esterifying kettle, gas-liquid separator, esterification column, condenser and phase splitter, the disposable esterifying kettle that adds of entrainment agent and the catalyzer vitriol oil, the step of intermittently replenishing, entering water cooler after esterification column side line extraction mixed solution and raw material heat exchange is cooled to 40 ℃ and enters phase splitter again, the all or part of esterification column circulation water entrainment that returns of the organic phase that obtains after phase-splitting (mainly containing entrainment agent), the stripping tower tower reactor obtains the product ethyl acetate.

The detailed process of the invention described above production method is as follows:

(1) high-order raw material tank Raw acetic acid, ethanol first are warming up to 50～60 ℃ with the heat exchange of side line extraction mixed solution, enter again preheater and ℃ left and right, steam condenses heat exchange to 70～80, then enter the esterification reboiler and be warming up to 105～110 ℃ of left and right, send at last esterifying kettle and react, the esterifying kettle gas phase enters esterification column and carries out rectifying;

(2) the disposable esterifying kettle that adds of entrainment agent and the catalyzer vitriol oil intermittently replenishes.Entrainment agent is carried water unnecessary in system secretly and is discharged after by the phase splitter phase-splitting from lateral line withdrawal function, and after the condensation of stripping tower top gaseous phase, circulation enters the phase splitter of esterification tower top, stripping tower tower reactor output product ethyl acetate;

(3) will mix with stripping tower overhead condensation liquid after the vapor condensation of esterification column tower top, after the phase splitter phase-splitting, thick ester moiety refluxes, part enters that stripping tower is refining, organic phase that esterification column side line extraction mixed solution is obtained after phase splitter separates is all or part of is back to esterification column circulation water entrainment, entrainment agent recycle.

In aforesaid method, the composition of step (2), (3) described esterification column tower top, stripping tower top gaseous phase is mainly water-ethyl acetate binary azeotrope, also has in addition a small amount of water-ethanol-ethyl acetate ternary azeotrope, for reducing the content of esterification column tower top ternary azeotrope, will guarantee the high acidity of esterifying kettle, namely acetic acid is excessive as far as possible.

In aforesaid method, the temperature of reaction of described esterifying kettle is 105～110 ℃, and pressure is 0.10～0.15MPa, and still acid (acetic acid) concentration is controlled at 65 ~ 85%; The esterification column tower top temperature is 70～72 ℃, and tower top pressure is 0.10～0.105MPa; Side line extraction mixeding liquid temperature is 80～90 ℃, and pressure is 0.10～0.12MPa; The stripping tower tower top temperature is 70～72 ℃, and tower top pressure is 0.10～0.105MPa, and the tower reactor product temperature is 80～84 ℃.

The present invention uses entrainment agent production ethyl acetate equipment used, mainly is made of high-order raw material tank, preheater, esterification reboiler, esterification column, stripping tower, esterifying kettle, gas-liquid separator, overhead condenser, tower top phase splitter, side line water cooler, side line phase splitter and pipeline.wherein, high-order raw material tank is connected with esterification column side line interchanger by pipeline, the side line exchanger heat brings out mouth and is connected with the side line water cooler, cold side outlet is connected with preheater, the preheater cold side outlet is connected with the import of esterification reboiler, one end of esterification reboiler is connected with the esterifying kettle feed end by pipeline, the discharge end of esterifying kettle is connected with the gas-liquid separator import by pipeline, the gas-liquid separator gaseous phase outlet is connected with the esterification column feed end, the gas-liquid separator liquid-phase outlet is connected with esterifying kettle top refluxing opening, the bottom of esterification column is connected by the feed end of pipeline with the esterification reboiler, esterification column is connected the top and is connected with condenser inlet by pipeline respectively with stripping tower, two top of tower condensator outlets are connected with mixing tank by pipeline, mixer outlet is connected with the import of top phase splitter, the thick ester outlet in the upper strata, bottom of top phase splitter is by pipeline and pump, be connected with stripping tower with the esterification column tower top respectively, lower floor's wastewater outlet of top phase splitter connects wastewater treatment equipment (not marking in figure) by pipeline, the top exit of top phase splitter is discharged non-condensable gas, the side line of esterification column is connected with the side line interchanger by pipeline, be connected with cooler inlet again, the side line cooler outlet is connected by the top inlet of pipeline with the side line phase splitter, the bottom upper organic phase outlet of side line phase splitter is connected with below, esterification column tower lateral line discharging position with pump by pipeline, the bottom wastewater outlet of side line phase splitter connects same wastewater treatment equipment (not marking in figure) by pipeline, the top exit of side line phase splitter is discharged non-condensable gas, enter in the esterifying kettle chuck from the steam of the steam power system chuck entrance end by esterifying kettle, enter in the esterification reboiler by esterification reboiler entrance end, the steam condenses after heat exchange is connected with the preheater inlet end by pipeline.

Compared with prior art, the present invention has following beneficial effect:

(1) the present invention uses the method for entrainment agent production ethyl acetate, utilize the principle of ethyl acetate and entrainment agent similar compatibility, large with water formation heterogeneous azeotrope and azeotrope water content, wherein, ethyl acetate-water, entrainment agent-water boiling-point difference both is between 15～20 ℃, is fit to side line and separates;

(2) the inventive method is by can the circulate water of enrichment in the system of taking out of of a small amount of entrainment agent, reduced the when quantity of reflux of thick ester of esterification column backflow, and need not increase equipment on the ethyl acetate conventional production equipment, throughput can increase by 30～50%, is fit to the reducing energy consumption of expanding production of existing production of ethyl device;

(3) the inventive method obvious economic, the energy consumption in energy decrease production process is compared with traditional method, and under the condition that does not increase equipment investment, the inventive method energy consumption has descended 20～40%.

Description of drawings

Fig. 1 is the device structure schematic diagram that the inventive method adopts, wherein, the 1st, high-order raw material tank, the 2nd, preheater, the 3rd, esterification reboiler, the 4th, esterifying kettle, the 5th, gas-liquid separator, the 6th, esterification column, the 7th, water cooler, the 10, the 11st, condenser, 8, the 9th, phase splitter, the 12nd, mixing tank, the 13rd, stripping tower, the 14th, interchanger.

Embodiment

Further explain the present invention below in conjunction with embodiment, but embodiment does not do any type of restriction to the present invention.

equipment of the present invention as shown in Figure 1, wherein: the raw material in high-order raw material tank 1 is connected with side line interchanger 14 by pipeline and carries out heat exchange, enter preheater 2 preheatings, preheater 2 outlets are connected with 3 imports of esterification reboiler, raw material is heated near esterification temperature in esterification reboiler 3, one end of esterification reboiler 3 is connected with esterifying kettle 4 feed ends by pipeline, the discharge end of esterifying kettle 4 is connected with gas-liquid separator 5 imports by pipeline, gas-liquid separator 5 gaseous phase outlets are connected with esterification column 6 feed ends, gas-liquid separator 5 liquid-phase outlets are connected with esterifying kettle 4 top refluxing openings, the bottom of esterification column 6 is connected by the feed end of pipeline with esterification reboiler 3, the top of esterification column 6 is connected with condenser 10 imports by pipeline, condenser 10, 11 outlets are connected by the top inlet of pipeline with mixing tank 12, the outlet of mixing tank 12 is connected with phase splitter 9 top inlet, the thick ester in the bottom of phase splitter 9 is connected with pump by pipeline to be connected with stripping tower with esterification column 6 tower tops and is connected, the bottom wastewater outlet of phase splitter 9 connects wastewater treatment equipment by pipeline, the top exit of phase splitter 9 is discharged non-condensable gas, the side line of esterification column 6 is connected with condenser 7 imports by pipeline, condenser 7 outlets are connected by the top inlet of pipeline with phase splitter 8, the thick ester in the bottom of phase splitter 8 and part fresh water are by pipeline and pump and esterification column 6 tower lateral line discharging position epimeres, discharging position hypomere, the subsequent fine distillation unit connects respectively, the bottom wastewater outlet of phase splitter 8 connects same wastewater treatment equipment by pipeline, the top exit of phase splitter 8 is discharged non-condensable gas, enter in the chuck of esterifying kettle 4 from the steam of the steam power system chuck entrance end by esterifying kettle 4, enter in esterification reboiler 3 by esterification reboiler 3 entrance ends, for esterifying kettle 4 and esterification reboiler 3 provide thermal source, steam after heat exchange is connected exit end by the exit end of esterifying kettle 4 chucks and is connected with preheater 2 entrance ends by pipeline with the esterification reboiler, the steam condenses after heat exchange is connected with steam power system with pipeline by preheater 2 exit end.

Embodiment 1

(proportioning of raw material is: the molar content of ethanol is 48% to the raw material that will be comprised of ethanol, acetic acid, the molar content of acetic acid is 52%), acetic acid is excessive, guarantee the high acidity of esterifying kettle, prevent that ethanol from entering esterification column too much, control to reach the purpose that esterification column tower top composition forms near ethyl acetate-water binary azeotropic as far as possible, thereby be conducive to the phase-splitting of esterification column tower top phase splitter, reduce thick ester water content.Entrainment agent is disposable to add, and feeding quantity is 5% (quality) of esterifying kettle still material, and intermittently trace replenishes.Adopt flow process shown in Figure 1 to carry out esterification-rectifying, the esterifying kettle temperature of reaction is 104～106 ℃, pressure is 0.12～0.13MPa, and esterification column overhead extraction temperature is 70～72 ℃, and pressure is 0.10～0.105MPa, side line extraction temperature is 84～88 ℃, pressure is 0.108～0.11MPa, 80～83 ℃ of stripping tower tower reactor temperature, and pressure is 0.108～0.11MPa, 70～72 ℃ of stripping tower tower top temperatures, pressure are 0.10～0.105MPa.In technical process, utilize the discharging of side line liquid phase and steam condensate to carry out preheating to charging, can reduce the esterifying kettle thermal load, and can reduce the cold general facilities consumption of side line.

Use chemical-process simulation software ASPEN PLUS to carry out analog calculation to reactor, esterification column, stripping tower whole process, calculation result shows that ethyl acetate product purity reaches 99.85wt%, and carry out energy consumption analysis, by contrasting with traditional processing technology, the energy-saving effect of processing method of the present invention is as shown in table 1.

Table 1 entrainment agent technique and traditional esterification technique energy consumption comparison

Table 1 shows, compares with traditional processing technology, relates to the entrainment agent energy saving technology successful of lateral line withdrawal function, and unit product (ton ester) energy consumption drops to 2.1 tons of steam by 3～3.5 tons of steam, and fall reaches 30%.

Embodiment 2

The raw material (proportioning of raw material is: the molar content of ethanol is 50%, and the molar content of acetic acid is 50%) that will be formed by ethanol, acetate mixture.Entrainment agent is disposable to add, and feeding quantity is 8% (quality) of esterifying kettle still material, and intermittently trace replenishes.Adopt flow process shown in Figure 1 to carry out esterification-rectifying, the esterifying kettle temperature of reaction is 105 ℃, pressure is 0.125MPa, and esterification column overhead extraction temperature is 71-72 ℃, and pressure is 0.105MPa, side line extraction temperature is 85～90 ℃, pressure is 0.108～0.11MPa, 80～83 ℃ of stripping tower tower reactor temperature, and pressure is 0.108～0.11MPa, 71 ~ 72 ℃ of stripping tower tower top temperatures, pressure are 0.10～0.105MPa.

Use chemical-process simulation software ASPEN PLUS to carry out analog calculation to reactor, esterification column, stripping tower whole process, calculation result is as shown in table 2, the ethyl acetate product purity is to 99.90wt%, and ethanol content is 0.01wt%, and water-content is 0.0032wt%.

Table 2Aspen Plus analog calculation forms (massfraction)

The analog calculation result is carried out the whole process energy spectrometer, and by contrasting with traditional processing technology, the energy-saving effect that draws processing method of the present invention is as shown in table 3.

Table 3 entrainment agent technique and traditional esterification technique energy consumption comparison

Table 3 shows, compares with traditional esterification production technology, relates to the entrainment agent energy saving technology successful of lateral line withdrawal function, and unit product (ton ester) energy consumption drops to 2.0 tons of steam by 3～3.5 tons of steam, fall nearly 30%; And can be from the angle of process intensification, the still acidacidity is high by adopting, alloy material esterifying kettle, high capacity tray technology and metal material high efficiency packing, new type heat exchanger, respectively from suppress erosion rate, accelerate speed of reaction, improve rectification efficiency, the intensity that increases heat exchange efficiency and device expands the scale of production and the industrialization engineering the aspects such as Stability Control problem that run into implement whole technical innovation project, estimate that industrial scale can enlarge 30～50%.

Claims (3)

1. a method of using entrainment agent production ethyl acetate, is characterized in that described entrainment agent is isobutyl propionate, propyl isobutyrate or its mixture;

Described method steps is as follows:

(1) high-order raw material tank Raw acetic acid and ethanol first are warming up to 50～60 ℃ with the heat exchange of side line extraction mixed solution, enter again preheater and steam condenses heat exchange to 70～80 ℃, enter the esterification reboiler and be warming up to 105～110 ℃, send at last esterifying kettle and react, the esterifying kettle gas phase enters esterification column and carries out rectifying;

(2) the disposable esterifying kettle that adds of entrainment agent and the catalyzer vitriol oil, intermittently replenish, entrainment agent is carried water unnecessary in system secretly and is discharged after by the phase splitter phase-splitting from lateral line withdrawal function, and after the condensation of stripping tower top gaseous phase, circulation enters the phase splitter of esterification tower top, stripping tower tower reactor output product ethyl acetate;

(3) will mix with stripping tower overhead condensation liquid after the vapor condensation of esterification column tower top, after the phase splitter phase-splitting, thick ester moiety refluxes, part enters that stripping tower is refining, organic phase that esterification column side line extraction mixed solution is obtained after phase splitter separates is all or part of is back to esterification column circulation water entrainment, entrainment agent recycle;

Wherein, described raw acetic acid and ethanol are counted according to molar content: ethanol 40～60%, acetic acid 40～60%.

2. use according to claim 1 the method for entrainment agent production ethyl acetate, it is characterized in that described entrainment agent is 3～8wt% of esterifying kettle still material, intermittently trace replenishes.

3. use according to claim 1 the method for entrainment agent production ethyl acetate, the temperature of reaction that it is characterized in that described esterifying kettle is 105～110 ℃, and pressure is 0.10～0.15MPa; The esterification column tower top temperature is 70～72 ℃, and tower top pressure is 0.10～0.105MPa; Side line extraction mixeding liquid temperature is 80～90 ℃, and pressure is 0.10 ~ 0.12MPa; The stripping tower tower top temperature is 70～72 ℃, and tower top pressure is 0.10～0.105MPa; The bottom product temperature is 80～84 ℃.