CN107641083A - A kind of power-saving technology of azeotropic joint variable-pressure rectification separating ethyl acetate and n-hexane - Google Patents
A kind of power-saving technology of azeotropic joint variable-pressure rectification separating ethyl acetate and n-hexane Download PDFInfo
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Abstract
The invention discloses the power-saving technology of a kind of azeotropic joint variable-pressure rectification separating ethyl acetate and n-hexane, belong to chemical separating purification art.The present invention is to caused ethyl acetate and n-hexane organic liquid waste in the production processes such as rubber, weaving, paint and pharmacy, by the use of methanol as entrainer through azeotropic distillation, compression rectification Jing Guo variable-pressure rectification process and the simple process of low-pressure distillation separation again, obtain the ethyl acetate, n-hexane and methanol of high-purity, meanwhile the purpose realized and saved using being thermally integrated.The present invention is simple with technique, easy to operate；Process continuity is strong, and controllability is high, and energy consumption is low；The purity of product is high, and impurity is few；Energy Resource Recycling Utilization, no waste gas, waste liquid and waste sludge discharge, be advantageous to environmental protection and save the energy.The recycling of organic liquid waste in industry is present invention can be widely used to, the recycling especially suitable for caused ethyl acetate and n-hexane waste liquid in large, medium and small type enterprise production process.
Description
Technical field
The invention belongs to chemical separating purification art, and in particular to combine variable-pressure rectification separating ethyl acetate to a kind of azeotropic
With the power-saving technology of n-hexane.
Background technology
N-hexane and ethyl acetate are all important organic solvents, are widely used in the neck such as rubber, weaving, paint and pharmacy
Domain, and in the final product must these completely out solvents, it is organic molten containing n-hexane and ethyl acetate so as to form
Agent waste liquid.The boiling point of n-hexane is 68.74 DEG C, and the boiling point of ethyl acetate is 77.06 DEG C, and the two can form minimum common at ambient pressure
Thing is boiled, azeotropic temperature is 68.00 DEG C, and azeotropic composition is to contain ethyl acetate mass fraction 34.30%, n-hexane mass fraction
65.70%, it can not be efficiently separated using the rectificating method of routine.In order to avoid waste of resource and environmental pollution, will contain
The waste liquid of n-hexane and ethyl acetate is for recycling and reuse just into problem urgently to be resolved hurrily.
It is existing separation n-hexane and ethyl acetate method, relate generally to two kinds of special rectificating methods i.e. extracting rectifying and
Azeotropic distillation.Such as《Computer and applied chemistry》August 28 day in 2012 volume 29 the 8th phase " ethyl acetate and n-hexane extraction essence
The simulation for evaporating process calculates " in a text, disclosed method is：Using dimethylformamide as extractant, to ethyl acetate and just oneself
The extracting rectifying process of alkane is simulated and optimized, the results showed that：Full tower number of theoretical plate is 30 pieces, and raw material enters in the 20th block of plate
Material, extractant feed in the 12nd block of plate, volumetric ratio 3, reflux ratio for 4.5 when, isolated ethyl acetate and n-hexane
Product purity can reach 99.00%.The major defect of the method is：(1) ethyl acetate and n-hexane can not be reclaimed simultaneously；(2)
Product purity is low；(3) toxicity of extractant is bigger, adds residual risk.And for example University Of Tianjin's Master's thesis in 2005 "
In the research of azeotropic distillation of having a rest a separation n-hexane and ethyl acetate mixture " text, disclosed method is：Use acetone as altogether
Agent is boiled, is reclaimed using the method separating ethyl acetate of intermittent azeotropic rectifying and the azeotropic mixture of n-hexane, then by the use of water as extractant
Entrainer acetone.When the mass ratio of acetone and n-hexane is 1.15, the yield of n-hexane is 75.15%, the receipts of ethyl acetate
Rate is 73.89%.The major defect of the method is：(1) technology controlling and process is more complicated, high energy consumption；(2) disintegrate-quality of product is grasped
Had a great influence as level；(3) product purity and entrainer purity ratio obtained by are relatively low, also need further processing can be only achieved and follow
The requirement that ring uses；(4) the 4th component water is added as extractant in solvent recovery stage, add the complexity that system separates
Degree.
The content of the invention
The purpose of the present invention is the weak point for existing separating ethyl acetate and n-hexane technology, there is provided a kind of azeotropic
The power-saving technology of joint variable-pressure rectification separating ethyl acetate and n-hexane.The present invention can form more low boiling using methanol with n-hexane
The azeotropic mixture and the pressure-sensitive character of methanol and n-hexane azeotropic system of point, using azeotropic distillation and the united work of variable-pressure rectification
Skill, ethyl acetate, n-hexane and methanol are efficiently separated, meanwhile, utilize the purpose for being thermally integrated realization energy-conservation.The technology has
Effect solves ethyl acetate and n-hexane forms the problem of Azeotrope separation is difficult, and entrainer recovery purity is low, has technological process
Simply, equipment investment is few, easy to maintenance, pollution-free, the features such as energy-conservation.
The present invention is achieved by the following technical solutions：A kind of azeotropic joint variable-pressure rectification combined separation ethyl acetate and
The power-saving technology of n-hexane, to the organic of the ethyl acetate caused by process such as production rubber, weaving, paint and pharmacy and n-hexane
Waste liquid, first with methanol as entrainer through azeotropic distillation, then compression rectification and low-pressure distillation point by variable-pressure rectification process
Separating process, obtain the ethyl acetate, n-hexane and methanol of high-purity.Meanwhile the purpose realized and saved using being thermally integrated.Its is specific
Step is as follows：(1) azeotropic distillation
To caused organic liquid waste in certain enterprise production process, consisting of：Ethyl acetate mass fraction 31.00%~
61.00%, n-hexane mass fraction 39.00%~69.00%, mass flow 1000.00kg/h, pass through feedstock pipeline
It is sent into azeotropy rectification column.Meanwhile the entrainer methanol by mass flow for 161.00~275.20kg/h, pass through solvent feed pipe
Azeotropy rectification column is sent on road in the lump, carries out azeotropic distillation, the Azeotrope separation that ethyl acetate and methanol are formed with n-hexane.Its
In, the feed entrance point of ethyl acetate and n-hexane is the 20th~25 block of column plate, and the feed entrance point of entrainer methanol is the 4th~6 piece
Column plate, the absolute pressure of azeotropy rectification column operation is 0.10MPa, and total theoretical cam curve is 31~35 pieces, and operating reflux ratio is
3.0~5.3.In the ethyl acetate liquid phase logistics that the isolated temperature of azeotropy rectification column bottom of towe is 74.40~76.69 DEG C, part
Liquid phase stream is by pipeline to heat exchanger, vaporization and liquid contact mass transfer in tower after being heated by high-pressure tower overhead vapours,
Part produces steam and liquid contact mass transfer in tower by pipeline to supplementary heat exchanger, by being vaporized after heating, and in addition one
Part is produced as ethyl acetate product by pipeline, recycling；In the isolated methanol of azeotropic distillation column overhead and just
The gaseous stream of hexane azeotropic mixture, condensed by Pipeline transport to condenser, condensed fluid temperature be 53.50~
53.56 DEG C, after condensed liquid is stored by Pipeline transport to return tank, azeotropy rectification column is partly back to by pipeline,
Contacted with the steam risen in tower and carry out mass transfer, another part condensate liquid is further processed.Isolated ethyl acetate
Product purity is 99.10%~99.90%.
(2) compression rectification of variable-pressure rectification process
After the completion of (1) step, by condensate liquid and the return tank of the storage of (1) step return tank by pipeline come part
After condensate liquid mixing, 0.62~1.02MPa is forced into by force (forcing) pump, the condensate liquid after pressurization conveys paramount by feeding pipe
The 6th~21 block of column plate of tower is pressed, carries out compression rectification, the methanol under n-hexane and high pressure and n-hexane azeotropic mixture are divided
From the absolute pressure of high-pressure tower operation is 0.60~1.00MPa, and total theoretical cam curve is 18~35 pieces, and operating reflux ratio is
1.5~3.0.In the n-hexane liquid phase stream that the isolated temperature of high-pressure rectification bottom of towe is 138.70~165.40 DEG C, part liquid
Phase logistics is heated by Pipeline transport to reboiler and vaporized, and is contacted with liquid in tower and is carried out mass transfer, partly as normal hexane product
Produced by pipeline, recycling；It is defeated by pipeline in the isolated methanol of high pressure column overhead and the gaseous stream of n-hexane
Deliver to heat exchanger and condense to temperature after 115.68~136.60 DEG C, partial condensation liquid to be delivered into return tank by pipeline and stored up
Deposit, another part condensate liquid is further processed.Isolated normal hexane product purity is 99.00%~99.50%.
(3) low-pressure distillation of variable-pressure rectification process
After the completion of (2) step, another part condensate liquid of (2) step return tank storage is sent into low by feed pipe
Tower is pressed, rectifying is carried out, the methanol under methanol and low pressure is separated with n-hexane azeotropic mixture, the absolute pressure of lower pressure column operation
For 0.10MPa, total theoretical cam curve is 18~34 pieces, and operating reflux ratio is 1.9~3.0.It is isolated in low pressure tower bottom
Temperature is 61.14~64.20 DEG C of methanol liquid phase stream, and fraction of stream is heated by Pipeline transport to reboiler and vaporized, with tower
Interior liquid contact carries out mass transfer, and fraction of stream is produced as methanol product by pipeline, recycling；In low pressure column overhead point
From the gaseous stream of methanol and n-hexane is obtained, it is 54.54~55.20 DEG C to be condensed by pipeline to heat exchanger to temperature
Afterwards, partial condensation liquid is stored by Pipeline transport to return tank, and another part condensate liquid passes through pipeline by pipeline and return tank
The condensate liquid mixing that conveying comes, force (forcing) pump pressurized treatments are sent into by pipeline.Isolated methanol product purity is 99.20%
~99.70%.
(4) it is thermally integrated
Realize and be thermally integrated in the heat exchanger of azeotropy rectification column bottom of towe, from high pressure column overhead temperatures be 115.68~
136.6 DEG C of gaseous stream, the azeotropic mixture mainly containing methanol and n-hexane, by pipeline to heat exchanger, with azeotropic essence
The ethyl acetate portion liquid phase stream that tower column bottom temperature is 74.40~76.69 DEG C is evaporated, is exchanged heat, the ethyl acetate of high-purity
Liquid all vaporizes, and the azeotropic mixture of methanol and n-hexane all condenses.After being thermally integrated, it can save energy 285.77~
319.07kW。
The present invention mainly has the following effects after using above technical scheme：
(1) purity of product is high, and impurity is few, can be with direct circulation reuse.Can be by ethyl acetate using the technology of the present invention
Efficiently separated with the organic liquid waste of n-hexane, obtained ethyl acetate purity is 99.10%~99.90%, and n-hexane purity is
99.00%~99.50%, can be with direct circulation reuse.
(2) the entrainer methanol purity of separation is high, can be directly recycled for reclaiming ethyl acetate and n-hexane, avoid
Product is polluted by the 4th component, and cost is effectively saved for enterprise.The technology of the present invention utilizes the pressure of methanol and n-hexane azeotropic mixture
Quick property, using the methanol of the isolated high-purity of variable-pressure rectification, avoid and introduce the 4th component water as extractant recovery methanol
Caused by contamination of products, obtained methanol purity be 99.20%~99.70%, can be back to direct circulation ethyl acetate and
The recovery process of n-hexane.
(3) technological process is simple and easy, and labor intensity is small, easy to operate, and equipment used is simple, cost-effective, practical
Strong, the great industry application of property.The azeotropic distillation being related in the inventive method, the compression rectification of variable-pressure rectification process and
Low-pressure distillation, the process such as it is thermally integrated, to the less demanding of equipment, for ease of maintenaince, and to device therefor without obvious loss, favorably
In the service life of extension device, production cost is reduced.
(4) technical process continuity is strong, and controllability is high, and energy consumption is low.The technical process being related in the inventive method is to connect
Continuous production, various technic indexs such as temperature, pressure, liquid level and purity etc. is easily controllable, efficiently solves product purity and is operated
The problem of level influences, improve the utilization rate of equipment.Meanwhile heat azeotropy rectification column tower using the hot logistics of high pressure column overhead
The cold logistics at bottom, realizes the recycling of energy, greatly reduces process energy consumption.
(5) resource is made full use of, is advantageous to environmental protection.A kind of azeotropic of the inventive method and variable-pressure rectification combined separation second
In the power-saving technology of acetoacetic ester and n-hexane, the composition of the organic liquid waste of involved ethyl acetate and n-hexane is containing acetic acid
Ethyl ester 31.00%~61.00%, it is 39.00%~69.00% containing n-hexane, ethyl acetate purity is after treatment
99.10%~99.90%, the purity of n-hexane is 99.00%~99.50%, meanwhile, the methanol reclaimed in technical process is pure
Spend for 99.20%~99.70%.Isolated ethyl acetate and n-hexane usually are returned into production process to carry out again
Utilize, resulting methanol, circulation and stress ethyl acetate and n-hexane are carried out as entrainer.This production process is without waste liquid, useless
Slag and waste gas discharge so that organic liquid waste resource is fully used, and is advantageous to environmental protection.
The recycling of organic liquid waste in industry is present invention can be widely used to, is given birth to especially suitable for large, medium and small type enterprise
The recycling of caused ethyl acetate and n-hexane waste liquid during production.
Brief description of the drawings
Fig. 1 is the process chart of the present invention.
In figure：1 condenser, 2 return tanks, 3 force (forcing) pumps, 4 return tanks, 5 condensers, 6 return tanks, 7 auxiliary reboilers, 8 is common
Boil rectifying column, 9 heat exchangers, 10 high-pressure towers, 11 reboilers, 12 lower pressure columns, 13 reboilers.
With reference to embodiment, the present invention is further illustrated.
Case study on implementation 1
As shown in figure 1, a kind of azeotropic and the power-saving technology of variable-pressure rectification combined separation ethyl acetate and n-hexane, its is specific
Step is as follows：(1) azeotropic distillation
To caused organic liquid waste in certain enterprise production process, consisting of：Ethyl acetate mass fraction 31.00%, just
Hexane mass fraction 69.00%, mass flow 1000.00kg/h, azeotropy rectification column 8 is sent into by feedstock pipeline.Together
When, by the entrainer methanol that mass flow is 275.20kg/h, azeotropy rectification column 8 is sent into by solvent feed pipeline in the lump, entered
Row azeotropic distillation, the Azeotrope separation that ethyl acetate and methanol are formed with n-hexane.Wherein, ethyl acetate and n-hexane enter
Material position is set to the 23rd block of column plate, and the feed entrance point of entrainer methanol is the 4th block of column plate, the absolute pressure that azeotropy rectification column 8 operates
For 0.10MPa, total theoretical cam curve is 35 pieces, operating reflux ratio 4.5.In the isolated temperature of the bottom of towe of azeotropy rectification column 8
The ethyl acetate liquid phase logistics for 76.61 DEG C is spent, Partial Liquid Phase logistics passes through high-pressure tower 10 by pipeline to heat exchanger 9
Vaporization and liquid contact mass transfer in tower after overhead vapours heating, partly by pipeline to auxiliary reboiler 7, after heating
Vaporization produces steam and liquid contact mass transfer in tower, and another part is produced as ethyl acetate product by pipeline, and recovery is again
Utilize；In the isolated methanol of the tower top of azeotropy rectification column 8 and the gaseous stream of n-hexane azeotropic mixture, pass through Pipeline transport to condensation
Device 1 is condensed, and condensed fluid temperature is 53.54 DEG C, and condensed liquid is stored by Pipeline transport to return tank 2
Afterwards, azeotropy rectification column 8 is partly back to by pipeline, is contacted with the steam risen in tower and carry out mass transfer, another part condensate liquid
It is further processed.Isolated ethyl acetate product purity is 99.90%.
(2) compression rectification of variable-pressure rectification process
After the completion of (1) step, by condensate liquid and the return tank 6 that (1) step return tank 2 stores by pipeline come portion
After dividing condensate liquid mixing, 1.02MPa is forced into by force (forcing) pump 3, the condensate liquid after pressurization is delivered to high pressure by feeding pipe
21st block of column plate of tower 10, compression rectification is carried out, the methanol under n-hexane and high pressure is separated with n-hexane azeotropic mixture, it is high
The absolute pressure that pressure tower 10 operates is 1.00MPa, and total theoretical cam curve is 30 pieces, operating reflux ratio 1.5.In high-pressure tower 10
The isolated temperature of bottom of towe is 165.40 DEG C of n-hexane liquid phase stream, and Partial Liquid Phase logistics is by Pipeline transport to reboiler 11
Heating vaporization, contacts with liquid in tower and carries out mass transfer, partly produced as normal hexane product by pipeline, recycling；
The gaseous stream of the isolated methanol of the tower top of high-pressure tower 10 and n-hexane, condensing to temperature to heat exchanger 9 by pipeline is
After 136.60 DEG C, partial condensation liquid is delivered to by return tank 4 by pipeline and stored, another part condensate liquid is carried out at next step
Reason.Isolated normal hexane product purity is 99.50%.
(3) low-pressure distillation of variable-pressure rectification process
After the completion of (2) step, another part condensate liquid of (2) step return tank V2 storages is sent into by feed pipe
Lower pressure column 12, rectifying is carried out, the methanol under methanol and low pressure is separated with n-hexane azeotropic mixture, lower pressure column 12 operates exhausted
It is 0.10MPa to pressure, total theoretical cam curve is 34 pieces, operating reflux ratio 3.0.In the isolated temperature in the bottom of lower pressure column 12
The methanol liquid phase stream for 64.20 DEG C is spent, fraction of stream is heated by Pipeline transport to reboiler 13 and vaporized, connect with liquid in tower
Touch and carry out mass transfer, fraction of stream is produced as methanol product by pipeline, recycling；It is isolated in the tower top of lower pressure column 12
The gaseous stream of methanol and n-hexane, by pipeline to condenser 5 condense to temperature be 55.20 DEG C after, partial condensation liquid
Stored by Pipeline transport to return tank 6, another part condensate liquid by pipeline and return tank 2 by pipeline come condensation
Liquid is mixed, and the pressurized treatments of force (forcing) pump 3 are sent into by pipeline.Isolated methanol product purity is 99.70%.
(4) it is thermally integrated
Realize and be thermally integrated in the heat exchanger 9 of the bottom of towe of azeotropy rectification column 8, be 136.60 DEG C from the tower top temperature of high-pressure tower 10
Gaseous stream, the azeotropic mixture mainly containing methanol and n-hexane, by pipeline to heat exchanger 9, with the tower of azeotropy rectification column 8
Bottom temperature is 76.61 DEG C of ethyl acetate portion liquid phase stream, is exchanged heat, and the ethyl acetate liquid of high-purity all vaporizes,
Methanol and n-hexane azeotropic mixture all condense.After being thermally integrated, 319.07kW can save energy.
Case study on implementation 2
A kind of specific steps of the power-saving technology of azeotropic and variable-pressure rectification combined separation ethyl acetate and n-hexane, with implementation
Case 1, wherein：
In (1) step, the composition of organic liquid waste is：Ethyl acetate mass fraction 40.00%, n-hexane mass fraction
60.00%, mass flow 1000.00kg/h, the mass flow of methanol azeotropic agent is 239.50kg/h.Ethyl acetate and just oneself
The feed entrance point into azeotropy rectification column 8 of alkane is the 25th block of column plate, and the feed entrance point of entrainer methanol is the 4th block of column plate, altogether
The absolute pressure that boiling rectifying column 8 operates is 0.10MPa, and total theoretical cam curve is 35 pieces, operating reflux ratio 3.0.In azeotropic
The temperature of the isolated ethyl acetate liquid phase logistics of the bottom of towe of rectifying column 8 is 76.29 DEG C, is separated in the tower top of azeotropy rectification column 8
It is 53.55 by Pipeline transport to 1 condensed fluid temperature of condenser to methanol and the gaseous stream of n-hexane azeotropic mixture
℃.Isolated ethyl acetate product purity is 99.80%.
In (2) step, by condensate liquid and the return tank 6 that (1) step return tank 2 stores by pipeline come part it is cold
After lime set mixing, 0.62MPa is forced into by force (forcing) pump 3, the condensate liquid after pressurization is delivered to high-pressure tower 10 by feeding pipe
The 25th block of column plate, the absolute pressure that high-pressure tower 10 operates be 0.60MPa, and total theoretical cam curve is 35 pieces, operating reflux ratio
For 2.7.In the n-hexane liquid phase stream that the isolated temperature of the bottom of towe of high-pressure tower 10 is 138.70 DEG C, separated in the tower top of high-pressure tower 10
The gaseous stream of methanol and n-hexane is obtained, temperature is condensed to by pipeline to heat exchanger 9 after 115.68 DEG C, to pass through pipe
Partial condensation liquid is delivered to return tank 4 and stored by road, and another part condensate liquid is further processed.Isolated n-hexane
Product purity is 99.30%.
In (3) step, the absolute pressure that lower pressure column 12 operates is 0.10MPa, and total theoretical cam curve is 25 pieces, is operated back
Stream is than being 1.9.In the bottom of lower pressure column 12, isolated temperature is 64.15 DEG C of methanol liquid phase stream, in the tower top point of lower pressure column 12
From the gaseous stream of methanol and n-hexane is obtained, it is 53.92 DEG C to be condensed by pipeline to condenser 5 to temperature.Separate
The methanol product purity arrived is 99.50%.
In (4) step, the gaseous stream temperature of the tower top of high-pressure tower 10 is 115.68 DEG C, the bottom of towe acetic acid second of azeotropy rectification column 8
The temperature of ester liquid phase stream is 76.29 DEG C, can save energy 427.70kW.
Case study on implementation 3
A kind of specific steps of the power-saving technology of azeotropic and variable-pressure rectification combined separation ethyl acetate and n-hexane, with implementation
Case 1, wherein：
In (1) step, the composition of organic liquid waste is：Ethyl acetate mass fraction 61.00%, n-hexane mass fraction
39.00%, mass flow 1000.00kg/h, the mass flow of methanol azeotropic agent is 161.00kg/h.Ethyl acetate and just oneself
The feed entrance point into azeotropy rectification column 8 of alkane is the 20th block of column plate, and the feed entrance point of entrainer methanol is the 6th block of column plate, altogether
The absolute pressure that boiling rectifying column 8 operates is 0.10MPa, and total theoretical cam curve is 31 pieces, operating reflux ratio 5.3.In azeotropic
The temperature of the isolated ethyl acetate liquid phase logistics of the bottom of towe of rectifying column 8 is 74.40 DEG C, is separated in the tower top of azeotropy rectification column 8
It is 53.56 by Pipeline transport to 1 condensed fluid temperature of condenser to methanol and the gaseous stream of n-hexane azeotropic mixture
℃.Isolated ethyl acetate product purity is 99.10%.
In (2) step, by condensate liquid and the return tank 6 that (1) step return tank 2 stores by pipeline come part it is cold
After lime set mixing, 0.92MPa is forced into by force (forcing) pump 3, the condensate liquid after pressurization is delivered to high-pressure tower 10 by feeding pipe
The 6th block of column plate, the absolute pressure that high-pressure tower 10 operates be 0.92MPa, and total theoretical cam curve is 18 pieces, and operating reflux ratio is
3.0.In the n-hexane liquid phase stream that the isolated temperature of the bottom of towe of high-pressure tower 10 is 159.39 DEG C, separated in the tower top of high-pressure tower 10
To methanol and the gaseous stream of n-hexane, temperature is condensed to by pipeline to heat exchanger 9 after 132.24 DEG C, to pass through pipeline
Partial condensation liquid is delivered into return tank 4 to store, another part condensate liquid is further processed.Isolated n-hexane production
Product purity is 99.00%.
In (3) step, the absolute pressure that lower pressure column 12 operates is 0.10MPa, and total theoretical cam curve is 18 pieces, is operated back
Stream is than being 3.0.In the bottom of lower pressure column 12, isolated temperature is 61.14 DEG C of methanol liquid phase stream, in the tower top point of lower pressure column 12
From the gaseous stream of methanol and n-hexane is obtained, it is 54.54 DEG C to be condensed by pipeline to condenser 5 to temperature.Separate
The methanol product purity arrived is 99.20%.
In (4) step, the gaseous stream temperature of the tower top of high-pressure tower 10 is 132.24 DEG C, the bottom of towe acetic acid second of azeotropy rectification column 8
The temperature of ester liquid phase stream is 74.40 DEG C, can save energy 285.77kW.
The above-mentioned case study on implementation of the present invention is only example to illustrate the invention, and is not the reality to the present invention
Apply the restriction of mode.For those of ordinary skill in the field, other can also be made on the basis of the above description
Various forms of changes and variation.Here all embodiments can not be exhaustive.Every technical side for belonging to the present invention
Row of the obvious changes or variations that case is amplified out still in protection scope of the present invention.
Claims (5)
1. the power-saving technology of a kind of azeotropic joint variable-pressure rectification separating ethyl acetate and n-hexane, it is characterised in that by certain enterprise
Caused ethyl acetate and n-hexane organic liquid waste in production process, make entrainer through azeotropic distillation, variable-pressure rectification using methanol
The simple process of compression rectification and the low-pressure distillation separation of process, recovery ethyl acetate, n-hexane and methanol, meanwhile, utilize heat
The purpose of integration realization energy-conservation.
2. the power-saving technology of a kind of azeotropic joint variable-pressure rectification separating ethyl acetate according to claim 1 and n-hexane,
It is characterized in that specific step is as follows：
(1) azeotropic distillation
To caused organic liquid waste in certain enterprise production process, consisting of：Ethyl acetate mass fraction 31.00%~
61.00%, n-hexane mass fraction 39.00%~69.00%, mass flow 1000.00kg/h, pass through feedstock pipeline
It is sent into azeotropy rectification column (8).Meanwhile the entrainer methanol by mass flow for 161.00~275.20kg/h, entered by solvent
Azeotropy rectification column (8) is sent on expects pipe road in the lump, carries out azeotropic distillation, the azeotropic mixture that ethyl acetate and methanol are formed with n-hexane
Separation.Wherein, the feed entrance point of ethyl acetate and n-hexane is the 20th~25 block of column plate, and the feed entrance point of entrainer methanol is the
4~6 blocks of column plates, the absolute pressure of azeotropy rectification column (8) operation is 0.10MPa, and total theoretical cam curve is 31~35 pieces, operation
Reflux ratio is 3.0~5.3.In the ethyl acetate that the isolated temperature of azeotropy rectification column (8) bottom of towe is 74.40~76.69 DEG C
Liquid phase stream, Partial Liquid Phase logistics are vaporized by pipeline to heat exchanger (9) after being heated by high-pressure tower (10) overhead vapours
With liquid contact mass transfer in tower, partly by pipeline to reboiler (7) is aided in, steam and tower are produced by being vaporized after heating
Interior liquid contact mass transfer, another part are produced as ethyl acetate product by pipeline；Separated in azeotropy rectification column (8) tower top
The gaseous stream of methanol and n-hexane azeotropic mixture is obtained, is condensed by Pipeline transport to condenser (1), condensed liquid
Temperature is 53.50~53.56 DEG C, after condensed liquid is stored by Pipeline transport to return tank (2), is partly returned by pipeline
Azeotropy rectification column (8) is flow to, is contacted with the steam risen in tower and carries out mass transfer.
(2) compression rectification of variable-pressure rectification process
After the completion of (1) step, by condensate liquid and the return tank (6) of (1) step return tank (2) storage by pipeline come portion
After dividing condensate liquid mixing, 0.62~1.02MPa is forced into by force (forcing) pump (3), the condensate liquid after pressurization is defeated by feeding pipe
The 6th~21 block of column plate of high-pressure tower (10) is delivered to, compression rectification is carried out, by the methanol under n-hexane and high pressure and n-hexane azeotropic
Thing is separated, and the absolute pressure of high-pressure tower (10) operation is 0.60~1.00MPa, and total theoretical cam curve is 18~35 pieces,
Operating reflux ratio is 1.5~3.0.In the n-hexane liquid that the isolated temperature of high-pressure tower (10) bottom of towe is 138.70~165.40 DEG C
Phase logistics, Partial Liquid Phase logistics are heated by Pipeline transport to reboiler (11) and vaporized, and are contacted with liquid in tower and are carried out mass transfer, portion
It is allocated as producing by pipeline for normal hexane product；In the isolated methanol of high-pressure tower (10) tower top and the gaseous stream of n-hexane,
Temperature is condensed to as after 115.68~136.60 DEG C by pipeline to heat exchanger (9), it is by pipeline that partial condensation liquid is defeated
Deliver to return tank (4) storage.
(3) low-pressure distillation of variable-pressure rectification process
After the completion of (2) step, by another part condensate liquid of (2) step return tank (4) storage, low pressure is sent into by feed pipe
Tower (12), rectifying is carried out, the methanol under methanol and low pressure is separated with n-hexane azeotropic mixture, lower pressure column (12) operates exhausted
It is 0.10MPa to pressure, total theoretical cam curve is 18~34 pieces, and operating reflux ratio is 1.9~3.0.At lower pressure column (12) bottom
The isolated temperature in portion is 61.14~64.20 DEG C of methanol liquid phase stream, and fraction of stream is by Pipeline transport to reboiler (13)
Heating vaporization, is contacted with liquid in tower and carries out mass transfer, and fraction of stream is produced as methanol product by pipeline；In lower pressure column (12)
The gaseous stream of the isolated methanol of tower top and n-hexane, by pipeline to condenser (5) condensation to temperature be 54.54~
After 55.20 DEG C, partial condensation liquid is stored by Pipeline transport to return tank (6), and another part condensate liquid passes through pipeline and backflow
Tank (2) by pipeline come condensate liquid mix, pass through pipeline be sent into force (forcing) pump (3) pressurized treatments.
(4) it is thermally integrated
Realize and be thermally integrated in the heat exchanger (9) of azeotropy rectification column (8) bottom of towe, be 115.68 from high-pressure tower (10) tower top temperature
~136.60 DEG C of gaseous stream, the azeotropic mixture mainly containing methanol and n-hexane, by pipeline to heat exchanger (9), with
Azeotropy rectification column (8) column bottom temperature is 74.40~76.69 DEG C of ethyl acetate portion liquid phase stream, is exchanged heat, high-purity
Ethyl acetate liquid all vaporizes, and the azeotropic mixture of methanol and n-hexane all condenses.
3. the power-saving technology of a kind of azeotropic joint variable-pressure rectification separating ethyl acetate according to claim 2 and n-hexane,
It is characterized in that：
In (1) step, the composition of organic liquid waste is：Ethyl acetate mass fraction 31.00%, n-hexane mass fraction 69.00%,
Mass flow is 1000.00kg/h, and the mass flow of methanol azeotropic agent is 275.20kg/h.The entrance of ethyl acetate and n-hexane
The feed entrance point of azeotropy rectification column (8) is the 23rd block of column plate, and the feed entrance point of entrainer methanol is the 4th block of column plate, azeotropic distillation
The absolute pressure of tower (8) operation is 0.10MPa, and total theoretical cam curve is 35 pieces, operating reflux ratio 4.5.In azeotropic distillation
The temperature of the isolated ethyl acetate liquid phase logistics of tower (8) bottom of towe is 76.61 DEG C, and in azeotropy rectification column (8), tower top separates
It is 53.54 by Pipeline transport to condenser (1) condensed fluid temperature to methanol and the gaseous stream of n-hexane azeotropic mixture
℃。
In (2) step, by condensate liquid and the return tank (6) of (1) step return tank (2) storage by pipeline come part it is cold
After lime set mixing, 1.02MPa is forced into by force (forcing) pump (3), the condensate liquid after pressurization is delivered to high-pressure tower by feeding pipe
(10) the 21st block of column plate, the absolute pressure of high-pressure tower (10) operation is 1.00MPa, and total theoretical cam curve is 30 pieces, operation
Reflux ratio is 1.5.It is 165.40 DEG C of n-hexane liquid phase stream in the isolated temperature of high-pressure tower (10) bottom of towe, in high-pressure tower
(10) gaseous stream of the isolated methanol of tower top and n-hexane, condensing to temperature by pipeline to heat exchanger (9) is
After 136.60 DEG C, partial condensation liquid is delivered to by return tank (4) by pipeline and stored, another part condensate liquid is carried out at next step
Reason.
In (3) step, the absolute pressure of lower pressure column (12) operation is 0.10MPa, and total theoretical cam curve is 34 pieces, operation backflow
Than for 3.0.In lower pressure column (12) bottom, isolated temperature is 64.20 DEG C of methanol liquid phase stream, in lower pressure column (12) tower top
The gaseous stream of isolated methanol and n-hexane, it is 55.20 DEG C by pipeline to condenser (5) condensation to temperature.
In (4) step, the gaseous stream temperature of high-pressure tower (10) tower top is 136.60 DEG C, azeotropy rectification column (8) bottom of towe acetic acid second
The temperature of ester liquid phase stream is 76.61 DEG C.
4. the power-saving technology of a kind of azeotropic joint variable-pressure rectification separating ethyl acetate according to claim 2 and n-hexane,
It is characterized in that：
In (1) step, the composition of organic liquid waste is：Ethyl acetate mass fraction 40.00%, n-hexane mass fraction 60.00%,
Mass flow is 1000.00kg/h, and the mass flow of methanol azeotropic agent is 239.50kg/h.The entrance of ethyl acetate and n-hexane
The feed entrance point of azeotropy rectification column (8) is the 25th block of column plate, and the feed entrance point of entrainer methanol is the 4th block of column plate, azeotropic distillation
The absolute pressure of tower (8) operation is 0.10MPa, and total theoretical cam curve is 35 pieces, operating reflux ratio 3.0.In azeotropic distillation
The temperature of the isolated ethyl acetate liquid phase logistics of tower (8) bottom of towe is 76.29 DEG C, and in azeotropy rectification column (8), tower top separates
It is 53.55 by Pipeline transport to condenser (1) condensed fluid temperature to methanol and the gaseous stream of n-hexane azeotropic mixture
℃。
In (2) step, by condensate liquid and the return tank (6) of (1) step return tank (2) storage by pipeline come part it is cold
After lime set mixing, 0.62MPa is forced into by force (forcing) pump (3), the condensate liquid after pressurization is delivered to high-pressure tower by feeding pipe
(10) the 25th block of column plate, the absolute pressure of high-pressure tower (10) operation is 0.60MPa, and total theoretical cam curve is 35 pieces, operation
Reflux ratio is 2.7.It is 138.70 DEG C of n-hexane liquid phase stream in the isolated temperature of high-pressure tower (10) bottom of towe, in high-pressure tower
(10) gaseous stream of the isolated methanol of tower top and n-hexane, condensing to temperature by pipeline to heat exchanger (9) is
After 115.68 DEG C, partial condensation liquid is delivered to by return tank (4) by pipeline and stored, another part condensate liquid is carried out at next step
Reason.
In (3) step, the absolute pressure of lower pressure column (12) operation is 0.10MPa, and total theoretical cam curve is 25 pieces, operation backflow
Than for 1.9.In lower pressure column (12) bottom, isolated temperature is 64.15 DEG C of methanol liquid phase stream, in lower pressure column (12) tower top
The gaseous stream of isolated methanol and n-hexane, it is 53.92 DEG C by pipeline to condenser (5) condensation to temperature.
In (4) step, the gaseous stream temperature of high-pressure tower (10) tower top is 115.68 DEG C, azeotropy rectification column (8) bottom of towe acetic acid second
The temperature of ester liquid phase stream is 76.29 DEG C.
5. the power-saving technology of a kind of azeotropic joint variable-pressure rectification separating ethyl acetate according to claim 2 and n-hexane,
It is characterized in that：
In (1) step, the composition of organic liquid waste is：Ethyl acetate mass fraction 61.00%, n-hexane mass fraction 39.00%,
Mass flow is 1000.00kg/h, and the mass flow of methanol azeotropic agent is 161.00kg/h.The entrance of ethyl acetate and n-hexane
The feed entrance point of azeotropy rectification column (8) is the 20th block of column plate, and the feed entrance point of entrainer methanol is the 6th block of column plate, azeotropic distillation
The absolute pressure of tower (8) operation is 0.10MPa, and total theoretical cam curve is 31 pieces, operating reflux ratio 5.3.In azeotropic distillation
The temperature of the isolated ethyl acetate liquid phase logistics of tower (8) bottom of towe is 74.40 DEG C, and in azeotropy rectification column (8), tower top separates
It is 53.56 by Pipeline transport to condenser (1) condensed fluid temperature to methanol and the gaseous stream of n-hexane azeotropic mixture
℃。
In (2) step, by condensate liquid and the return tank (6) of (1) step return tank (2) storage by pipeline come part it is cold
After lime set mixing, 0.92MPa is forced into by force (forcing) pump (3), the condensate liquid after pressurization is delivered to high-pressure tower by feeding pipe
(10) the 6th block of column plate, the absolute pressure of high-pressure tower (10) operation is 0.92MPa, and total theoretical cam curve is 18 pieces, is operated back
Stream is than being 3.0.It is 159.39 DEG C of n-hexane liquid phase stream in the isolated temperature of high-pressure tower (10) bottom of towe, in high-pressure tower (10)
The gaseous stream of the isolated methanol of tower top and n-hexane, temperature is condensed to as 132.24 by pipeline to heat exchanger (9)
After DEG C, partial condensation liquid is delivered to by return tank (4) by pipeline and stored, another part condensate liquid is further processed.
In (3) step, the absolute pressure of lower pressure column (12) operation is 0.10MPa, and total theoretical cam curve is 18 pieces, operation backflow
Than for 3.0.In lower pressure column (12) bottom, isolated temperature is 61.14 DEG C of methanol liquid phase stream, in lower pressure column (12) tower top
The gaseous stream of isolated methanol and n-hexane, it is 54.54 DEG C by pipeline to condenser (5) condensation to temperature.
In (4) step, the gaseous stream temperature of high-pressure tower (10) tower top is 132.24 DEG C, azeotropy rectification column (8) bottom of towe acetic acid second
The temperature of ester liquid phase stream is 74.40 DEG C.
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| CN109956866A (en) * | 2019-03-11 | 2019-07-02 | 长江师范学院 | A method of from ethyl acetate and normal heptane are separated and recovered in industry in organic sewage |
| CN110724023A (en) * | 2019-11-07 | 2020-01-24 | 岳阳金瀚高新技术股份有限公司 | Preparation method of 2-methylpentane, 3-methylpentane and n-hexane |
| CN114853607A (en) * | 2021-02-04 | 2022-08-05 | 万华化学集团股份有限公司 | Monomer-containing solvent refining system and process |
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| CN107011171A (en) * | 2017-04-14 | 2017-08-04 | 长江师范学院 | The system and method for variable-pressure rectification separating ethyl acetate and n-hexane azeotropic system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109956866A (en) * | 2019-03-11 | 2019-07-02 | 长江师范学院 | A method of from ethyl acetate and normal heptane are separated and recovered in industry in organic sewage |
| CN110724023A (en) * | 2019-11-07 | 2020-01-24 | 岳阳金瀚高新技术股份有限公司 | Preparation method of 2-methylpentane, 3-methylpentane and n-hexane |
| CN114853607A (en) * | 2021-02-04 | 2022-08-05 | 万华化学集团股份有限公司 | Monomer-containing solvent refining system and process |
| CN114853607B (en) * | 2021-02-04 | 2023-09-19 | 万华化学集团股份有限公司 | Monomer-containing solvent refining system and process |
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