CN112538002B - Process method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation - Google Patents
Process method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation Download PDFInfo
- Publication number
- CN112538002B CN112538002B CN202011421049.6A CN202011421049A CN112538002B CN 112538002 B CN112538002 B CN 112538002B CN 202011421049 A CN202011421049 A CN 202011421049A CN 112538002 B CN112538002 B CN 112538002B
- Authority
- CN
- China
- Prior art keywords
- tower
- butanediol
- ethylene glycol
- entrainer
- entrainer recovery
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
- C07C29/82—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation by azeotropic distillation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to a process method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation, which comprises the steps of sending a mixture of ethylene glycol and 1, 2-butanediol and a entrainer diethyl oxalate to an ethylene glycol refining tower for separating and refining an ethylene glycol product, sending the azeotropic mixture of the 1, 2-butanediol and diethyl oxalate at the tower top to an entrainer recovery tower, recovering the entrainer diethyl oxalate at the tower bottom of the entrainer recovery tower and circulating the azeotropic mixture to an ethylene glycol refining tower for use, sending the azeotropic mixture of the 1, 2-butanediol and diethyl oxalate at the tower top of the entrainer recovery tower to a butanediol removing tower, separating and refining the 1, 2-butanediol product at the tower bottom of the butanediol removing tower, and circulating the azeotropic mixture of the 1, 2-butanediol and diethyl oxalate at the tower top of the butanediol removing tower to the entrainer recovery tower. The invention provides a method for separating ethylene glycol and 1, 2-butanediol from a mixture of ethylene glycol and 1, 2-butanediol in a dimethyl oxalate process route for preparing ethylene glycol from coal by using diethyl oxalate as an entrainer, and a process pipeline cannot be blocked in the production process.
Description
Technical Field
The invention relates to the technical field of chemical separation, in particular to a method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation, and particularly relates to a method for separating and refining ethylene glycol and 1, 2-butanediol from crude ethylene glycol in a coal-to-ethylene glycol route.
Background
Ethylene glycol is used as an important chemical raw material, is mainly used for producing polyester terylene, polyester resin, a plasticizer, a surfactant, synthetic fibers and the like, can also be used as a solvent, a cooling liquid and the like of dye and printing ink, and has become the largest ethylene glycol consuming country in the world in China. In order to reduce the dependence on petroleum resources, the coal-to-ethylene glycol route is more and more emphasized, and has important practical significance for China.
In the dimethyl oxalate process route for preparing ethylene glycol from coal, the boiling points of ethylene glycol and a byproduct 1, 2-butanediol are relatively close and have a difference of 4.5 ℃, and the ethylene glycol and the byproduct can form a low-point azeotrope, so that the ethylene glycol and the byproduct 1, 2-butanediol are difficult to completely separate by adopting a common rectification technology.
The conventional methods comprise pressure swing distillation, extractive distillation, reactive distillation, selective adsorption, azeotropic distillation and the like. In the pressure swing distillation separation method, huizenga and Sanders realize the separation of ethylene glycol and 1, 2-butanediol, 99.6 percent of ethylene glycol is obtained from a high-pressure tower kettle, 1, 2-butanediol cannot be effectively separated from a low-pressure tower kettle, and the composition of an azeotrope of the ethylene glycol and the 1, 2-butanediol is small along with the pressure change, so that the circulation volume is large, the operation load of the tower is increased, and the practical application is not facilitated. For the extractive distillation separation method, the poplars indicate that the ethylene glycol and the 1, 2-butanediol have high boiling points, the selection of a third polar solvent with a higher boiling point is difficult, and in addition, the recovery energy consumption of the subsequent third component solvent is high, so that the process technology loses advantages. For the reactive distillation separation method, gaoxin et al propose a reactive distillation process for separating ethylene glycol and 1, 2-butanediol by using acetone, choptade and Sharma propose to convert dihydric alcohols such as ethylene glycol into acetal compounds with high boiling point difference by using aldol condensation reaction so as to reduce the separation difficulty, but two main problems of reactive distillation are too long process flow and too much water consumption of hydrolysis reaction. For selective adsorption, ethylene glycol and 1, 2-butanediol solution are purified by MF1 zeolite adsorption bed, the purity of ethylene glycol can reach 99.8%, but the problems of short service life of adsorbent, large regeneration difficulty, small production capacity and the like restrict the industrialization of the adsorbent.
As for the azeotropic distillation separation method, the great wealth and the Zhengmingyuan and the like indicate that the relative volatility between the diols can be obviously improved by adopting the azeotropic distillation, so that the number of theoretical plates is reduced, the fixed cost of a distillation tower is reduced, most of the entrainers discovered at present form an azeotrope with a main product, namely the glycol, and therefore, the using amount of the entrainers and the energy consumption are high. The document CN108017517B avoids the problem that an azeotropic agent and a main product ethylene glycol form an azeotrope, and adopts DMO azeotropic agent and 1, 2-butanediol to form an azeotrope, so that the ethylene glycol with the purity of 99.9 percent and the 1, 2-butanediol with the purity of 99.5 percent can be obtained. But the process is pure and has the following defects: the freezing point of the adopted entrainer DMO is 54 ℃, a process pipeline is easy to block in the production process, and the overhaul and the maintenance are inconvenient; the ethylene glycol separation tower and the ethylene glycol refining tower are operated under the pressure of 8-10 bar, the boiling point of the ethylene glycol is 265-280 ℃, however, the ethylene glycol is a heat-sensitive substance and is easy to polymerize at high temperature; the operating pressures of the ethylene glycol separation tower, the ethylene glycol refining tower, the low-pressure tower and the high-pressure tower are respectively 8-10 bar, 5-10 bar and 10-30 bar, pressure vessel equipment is required, and the equipment investment cost is high; the process is operated under high pressure, the higher the distillation pressure is, the smaller the relative volatility is, the more difficult the separation becomes, and simultaneously, the tower bottom and the tower top have high temperature, a high-grade heat source needs to be adopted, and the circulating consumption of cooling water is large, which means that the operation cost is high.
Disclosure of Invention
The invention aims to solve the technical problems of high separation energy consumption and high equipment investment cost in the prior art, and provides a method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation. The inventor of the application finds that diethyl oxalate only forms an azeotrope with 1, 2-butanediol and does not form an azeotrope with ethylene glycol in the research and development process, and the separation method provided based on the finding has the characteristics of low energy consumption, high purity of the obtained ethylene glycol and 1, 2-butanediol and high yield.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for separating ethanediol and 1, 2-butanediol by azeotropic distillation, after sending mixture of ethanediol and 1, 2-butanediol and diethyl oxalate of entrainer to ethanediol refining tower to separate and refine the ethanediol product, the top of the tower is azeotropic mixture of 1, 2-butanediol and diethyl oxalate, send to entrainer recovery tower and take off the double-tower procedure that the butanediol tower forms, the bottom of the tower of the entrainer recovery tower retrieves the diethyl oxalate of entrainer and circulates to the ethanediol refining tower to use, send azeotropic mixture of 1, 2-butanediol and diethyl oxalate of the top of the tower of the entrainer recovery tower to take off the butanediol tower, take off the bottom of the butanediol tower to separate and refine 1, 2-butanediol product, take off azeotropic mixture of 1, 2-butanediol and diethyl oxalate of the top of the butanediol tower to circulate and send to the entrainer recovery tower; wherein, the tower top gas of the entrainer recovery tower is used as a heat source of a reboiler of a tower kettle of the butanediol removal tower.
In the technical scheme, the operation pressure of the ethylene glycol refining tower is preferably 2-35 kPa, the theoretical plate number is 35-80, the reflux ratio is 5-14, and the temperature of the tower kettle is not more than 165 ℃.
In the technical scheme, preferably, the operating pressure of the entrainer recovery tower is 80-115 kPa, the theoretical plate number is 20-60, the reflux ratio is 5-14, and the temperature of the tower kettle is not more than 191 ℃.
In the above technical scheme, preferably, the operating pressure of the debutanizing column is 2-25 kPa, the theoretical plate number is 20-60, the reflux ratio is 8-18, and the temperature of the column bottom is not more than 155 ℃.
In the above aspect, the azeotropic agent recovery column preferably contains 1, 2-butanediol at a concentration of 19.8 to 30.8 (wt%) in the azeotropic gas at the top of the column.
In the above technical solution, preferably, the overhead azeotrope of the debutanizer contains 1, 2-butanediol at a concentration of 5.7 to 18.5 (wt%).
In the above technical scheme, preferably, after heat exchange is performed on the top gas of the entrainer recovery tower which is used as a heat source of the reboiler at the bottom of the butanediol removal tower, a part of the top gas returns to the entrainer recovery tower to be used as reflux liquid, and the rest of the top gas is sent to the butanediol removal tower.
In the above technical scheme, preferably, the ethylene glycol refining tower, the entrainer recovery tower and the butanediol removal tower are one or a combination of a plate tower, a bulk packed tower and a regular packed tower.
A process unit for separating glycol and 1, 2-butanediol by azeotropic distillation comprises a glycol refining tower, an entrainer recovery tower and a butanediol removing tower, wherein a tower kettle discharge port of the glycol refining tower is connected with a glycol refining tower kettle pump, a glycol product cooler and a glycol product tank through pipelines; the outlet of the top of the ethylene glycol refining tower is connected with an ethylene glycol refining tower condenser, an ethylene glycol refining tower reflux tank and an ethylene glycol refining tower reflux pump through pipelines, the outlet of the ethylene glycol refining tower reflux pump is divided into two paths, one path is connected with the top reflux port of the ethylene glycol refining tower, the other path is connected with the inlet of an entrainer recovery tower, the outlet of the bottom of the entrainer recovery tower is connected with an entrainer inlet pipeline of the ethylene glycol refining tower through an entrainer recovery tower bottom pump, the outlet of the top of the entrainer recovery tower is connected with the shell pass inlet of the entrainer recovery tower condenser through a pipeline, the shell pass outlet of the entrainer recovery tower condenser is connected with the entrainer recovery tower reflux tank and the entrainer recovery tower reflux pump, the outlet of the reflux pump of the entrainer recovery tower is divided into two paths, one path is connected to the top reflux port of the entrainer recovery tower, the other path is connected to the feed inlet of the butanediol removing tower, the discharge port at the top of the butanediol removing tower is connected with a butanediol removing tower condenser, a butanediol removing tower reflux tank and a butanediol removing tower reflux pump through pipelines, the outlet of the butanediol removing tower reflux pump is divided into two paths, one path is connected to the top reflux port of the butanediol removing tower, the other path is connected to the feed inlet of the entrainer recovery tower, and the discharge port at the bottom of the butanediol removing tower is connected with a butanediol removing tower kettle pump, a 1, 2-butanediol product cooler and a 1, 2-butanediol product tank through pipelines.
The condenser of the entrainer recovery tower is simultaneously used as a reboiler of the butanediol removing tower, and the inlet and the outlet of the tube pass of the condenser of the entrainer recovery tower are respectively connected with the tower kettle of the butanediol removing tower. In order to further supplement heat, the tower bottom of the butanediol removing tower is connected with a butanediol removing tower supplement reboiler.
The invention has the following beneficial effects:
1. the invention provides a method for separating ethylene glycol and 1, 2-butanediol from a mixture of ethylene glycol and 1, 2-butanediol in a dimethyl oxalate process route for preparing ethylene glycol from coal by using diethyl oxalate as an entrainer, wherein the freezing point of the diethyl oxalate is-40.6 ℃, and a process pipeline cannot be blocked in the production process.
2. The ethylene glycol refining tower is operated under vacuum, and the ethylene glycol is not easy to polymerize.
3. The whole process is operated under low pressure, no pressure vessel is involved, the equipment investment cost is low, and the temperature of the tower kettle under low pressure is low, so that a high-grade heat source is not needed.
4. The top gas of the entrainer recovery tower is used as a heat source of a reboiler of a butanediol removal tower kettle, so that the steam consumption of the butanediol removal tower is reduced, the circulating water consumption of a condenser of the entrainer recovery tower is saved, the operation cost of the process is reduced, and the economic benefit is obvious.
Drawings
FIG. 1 is a process flow diagram of the present invention employing azeotropic distillation.
In FIG. 1, T101 is an ethylene glycol refining tower, T102 is an entrainer recovery tower, T103 is a butanediol removing tower, E101 is an ethylene glycol refining tower reboiler, E102 is an ethylene glycol refining tower condenser, E103 is an ethylene glycol product cooler, E201 is an entrainer recovery tower reboiler, E202 is an entrainer recovery tower condenser and also a butanediol removing tower reboiler, E301 is a butanediol removing tower supplement reboiler, E302 is a butanediol removing tower condenser, E303 is a 1, 2-butanediol product cooler, P101 is an ethylene glycol refining tower reflux pump, P102 is an ethylene glycol refining tower kettle pump, P201 is an entrainer recovery tower reflux pump, P202 is an entrainer recovery tower kettle pump, P301 is a butanediol removing tower reflux pump, P302 is a butanediol removing tower kettle pump, V101 is an ethylene glycol refining tower reflux tank, V102 is an ethylene glycol product tank, V201 is an entrainer recovery tower reflux tank, V301 is a butanediol removing tower reflux tank, V302 is a 1, 2-butanediol product tank, 1 is a supplement entrainer diethyl oxalate, 2 is a mixture of ethylene glycol and 1, 2-butanediol, 3 is an ethylene glycol product, 4 is an azeotropic mixed liquid of 1, 2-butanediol and diethyl oxalate, 5 is an entrainer diethyl oxalate, 6 is an azeotropic mixed gas of 1, 2-butanediol and diethyl oxalate at the top of the entrainer recovery tower, 7 is an azeotropic mixed liquid of 1, 2-butanediol and diethyl oxalate, 8 is a 1, 2-butanediol product, and 9 is an azeotropic circulating liquid of 1, 2-butanediol and diethyl oxalate.
Detailed Description
The method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation according to the present invention will be described in further detail with reference to specific examples.
A process unit for separating glycol and 1, 2-butanediol by azeotropic distillation comprises a glycol refining tower T101, an entrainer recovery tower T102 and a butanediol removing tower T103, wherein the glycol refining tower T101 is provided with two feed inlets, the tower kettle of the glycol refining tower T101 is connected with a glycol refining tower reboiler E101, and the tower kettle discharge outlet of the glycol refining tower T101 is sequentially connected with a glycol refining tower kettle pump P102, a glycol product cooler E103 and a glycol product tank V102 through pipelines. The outlet of the reflux pump P101 of the ethylene glycol refining tower is divided into two paths, one path is connected to the top reflux port of the ethylene glycol refining tower, and the other path is connected to the feed inlet of the entrainer recovery tower T102. The entrainer recovery column T102 has two feed ports. The tower bottom of the entrainer recovery tower T102 is connected with an entrainer recovery tower reboiler E201, and the tower bottom discharge port of the entrainer recovery tower T102 is connected with an entrainer inlet pipeline of the ethylene glycol refining tower T101 through an entrainer recovery tower kettle pump P202. The top outlet of the entrainer recovery tower T102 is connected to the shell side inlet of an entrainer recovery tower condenser E202 through a pipeline, and the entrainer recovery tower condenser E202 is simultaneously used as a reboiler of a butanediol removal tower T103. The shell pass outlet of the entrainer recovery tower condenser E202 is sequentially connected with an entrainer recovery tower reflux tank V201 and an entrainer recovery tower reflux pump P201, the outlet of the entrainer recovery tower reflux pump P201 is divided into two paths, one path is connected to the top reflux port of the entrainer recovery tower T102, the other path is connected to the feed inlet of the debutanizer T103, the top discharge port of the debutanizer T103 is sequentially connected with a debutanizer condenser E302, a debutanizer reflux tank V301 and a debutanizer reflux pump P301 through pipelines, the outlet of the debutanizer reflux pump P301 is divided into two paths, one path is connected to the top reflux port of the debutanizer T103, and the other path is connected to the other feed inlet of the debutanizer T102. A tower bottom discharge port of the butanediol removing tower T103 is sequentially connected with a butanediol removing tower bottom pump P302, a 1, 2-butanediol product cooler E303 and a 1, 2-butanediol product tank V302 through pipelines. The tower kettle of the butanediol removing tower T103 is connected with a butanediol removing tower supplement reboiler E301.
A process method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation comprises the steps of sending a mixture 2 of ethylene glycol and 1, 2-butanediol and an azeotropic agent diethyl oxalate 5 to an ethylene glycol refining tower T101, supplying heat to the ethylene glycol refining tower by an ethylene glycol refining tower reboiler E101, separating and refining to obtain an ethylene glycol product 3, pumping the ethylene glycol product 3 through an ethylene glycol refining tower kettle pump P102 by an ethylene glycol product cooler E103, then entering an ethylene glycol product tank V102, condensing azeotropic mixed gas of 1, 2-butanediol and diethyl oxalate at the top of the tower through an ethylene glycol refining tower condenser E102, then entering a reflux tank V101 of the ethylene glycol refining tower, pressurizing the reflux tank liquid through an ethylene glycol refining tower reflux pump P101, then partially refluxing, sending azeotropic agent 4 of 1, 2-butanediol and diethyl oxalate to a double-tower flow composed of an azeotropic agent recovery tower T102 and a butanediol removal tower T103, recycling azeotropic agent diethyl oxalate 5 at the bottom of the azeotropic agent recovery tower T102 to an azeotropic agent recovery tower T202, supplementing heat to the azeotropic agent recovery tower T101, supplementing heat-azeotropic agent reboiler E202, recycling tower heat-exchanger reboiler E202, recycling tower heat the azeotropic agent E102, recycling tower is a butanediol recycling tower reboiler E202, recycling tower is also provided with an azeotropic agent recycling tower reboiler E201, recycling tower heat-recycling azeotropic agent recycling tower. After the liquid in the reflux tank V201 of the entrainer recovery tower is pressurized by a reflux pump P201 of the entrainer recovery tower, a part of the liquid reflows, a part of azeotropic mixed liquid 7 of 1, 2-butanediol and diethyl oxalate is sent to a butanediol removing tower T103, a butanediol removing tower supplement reboiler E301 supplies heat for the butanediol removing tower T103, 1, 2-butanediol product 8 is separated and refined from the bottom of the butanediol removing tower T103, the azeotropic mixed gas of 1, 2-butanediol and diethyl oxalate at the top of the butanediol removing tower T103 is condensed by a butanediol removing tower condenser E302 and then enters the butanediol removing tower reflux tank V301, the liquid in the reflux tank partially reflows after being pressurized by a butanediol removing reflux pump P301, and a part of azeotropic circulating liquid 9 of 1, 2-butanediol and diethyl oxalate circulates to the entrainer recovery tower T102.
The operation pressure of the ethylene glycol refining tower T101 is absolute pressure 2-35 kPa, the theoretical plate number is 35-80, the reflux ratio is 5-14, and the temperature of the tower kettle is not more than 165 ℃.
The operation pressure of the entrainer recovery tower T102 is 80-115 kPa, the theoretical plate number is 20-60, the reflux ratio is 5-14, and the temperature of the tower kettle is not more than 191 ℃.
The operation pressure of the butanediol removing tower T103 is 2-25 kPa absolute pressure, the number of theoretical plates is 20-60, the reflux ratio is 8-18, and the temperature of the tower kettle is not more than 150 ℃.
The azeotropic agent recovery column T102 has a concentration of 1, 2-butanediol in the azeotropic gas 6 at the column top of 19.8 to 30.8 (wt%).
The azeotrope 9 at the top of the butanediol removing tower T103 contains 1, 2-butanediol with the concentration of 5.7-17.5 wt%.
The ethylene glycol refining tower T101, the entrainer recovery tower T102 and the butanediol removal tower T103 are combined by one or more of a plate tower, a bulk packed tower or a regular packed tower.
Example 1
Using the flow chart shown in FIG. 1, a mixture 2 containing 98.3% (wt%) of ethylene glycol and 1.7% (wt%) of 1, 2-butanediol was fed into an ethylene glycol refining column T101 together with diethyl oxalate 5 as an entrainer at a flow rate of 1000 kg/h.
The operation pressure of the ethylene glycol refining tower T101 is 35kPa, the theoretical plate number is 45, the reflux ratio is 14, and the tower kettle temperature is 164.7 ℃. 983.1kg/h, 99.99% (wt%) ethylene glycol was obtained in the bottom of the column.
The operating pressure of the entrainer recovery tower T102 is 115kPa, the theoretical plate number is 30, the reflux ratio is 14, and the tower kettle temperature is 190.1 ℃.
The operation pressure of the butanediol removing tower T103 is absolute pressure 25kPa, the theoretical plate number is 30, the reflux ratio is 18, and the tower kettle temperature is 154.8 ℃. The bottom of the column gave 16.9kg/h, 99.8% (wt%) of 1, 2-butanediol.
The amount of diethyl oxalate for supplementing fresh entrainer is 0.03kg/h. The azeotropic agent recovery column contained 1, 2-butanediol in the azeotropic gas at the column top in a concentration of 25.8 (wt%). The overhead azeotrope from the debutanizer contained 1, 2-butanediol at a concentration of 17.5 (wt%).
Example 2
Using the flow chart shown in FIG. 1, a mixture 2 containing 98.3% (wt%) of ethylene glycol and 1.7% (wt%) of 1, 2-butanediol was fed into an ethylene glycol refining column T101 together with diethyl oxalate 5 as an entrainer at a flow rate of 1000 kg/h.
The operation pressure of the ethylene glycol refining tower T101 is absolute pressure 30kPa, the number of theoretical plates is 50, the reflux ratio is 12.9, and the temperature of the tower kettle is 160.4 ℃. 983.1kg/h, 99.99% (wt%) ethylene glycol was obtained in the bottom of the column.
The operating pressure of the entrainer recovery tower T102 is 110kPa absolute pressure, the theoretical plate number is 35, the reflux ratio is 12.8, and the tower kettle temperature is 188.5 ℃.
The operation pressure of the butanediol removing tower T103 is 21kPa absolute pressure, the theoretical plate number is 35, the reflux ratio is 16.5, and the tower kettle temperature is 150.3 ℃. The bottom of the column gave 16.9kg/h, 99.8% (wt%) of 1, 2-butanediol.
The amount of diethyl oxalate for supplementing fresh entrainer is 0.03kg/h. The azeotropic agent recovery column contained 1, 2-butanediol in the azeotropic gas at the top of the column at a concentration of 25.5 (wt%). The overhead azeotrope from the debutanizer contained 1, 2-butanediol at a concentration of 16.5 (wt%).
Example 3
Using the flow chart shown in FIG. 1, a mixture 2 containing 97.1% (wt%) of ethylene glycol and 2.9% (wt%) of 1, 2-butanediol was fed into an ethylene glycol refining column T101 together with diethyl oxalate 5 as an entrainer at a flow rate of 1000 kg/h.
The operation pressure of the ethylene glycol refining tower T101 is 25kPa absolute pressure, the theoretical plate number is 55, the reflux ratio is 11.8, and the tower kettle temperature is 155.4 ℃. 971.1kg/h, 99.98% (wt%) of ethylene glycol were obtained in the bottom of the column.
The operating pressure of the entrainer recovery tower T102 is 105kPa, the theoretical plate number is 40, the reflux ratio is 11.6, and the tower kettle temperature is 186.8 ℃.
The operation pressure of the butanediol removing tower T103 is 17kPa, the theoretical plate number is 40, the reflux ratio is 15, and the tower kettle temperature is 145 ℃. The column bottom gave 28.9kg/h, 99.8% (wt%) of 1, 2-butanediol.
The amount of diethyl oxalate for supplementing fresh entrainer is 0.02kg/h. The azeotropic agent recovery column contained 1, 2-butanediol in the azeotropic gas at the top of the column at a concentration of 25.2 (wt%). The overhead azeotrope from the debutanizer contained 1, 2-butanediol at a concentration of 15.4 wt%.
Example 4
Using the flow chart shown in FIG. 1, a mixture 2 containing 97.1% (wt%) of ethylene glycol and 2.9% (wt%) of 1, 2-butanediol was fed into an ethylene glycol refining column T101 together with diethyl oxalate 5 as an entrainer at a flow rate of 1000 kg/h.
The operating pressure of the ethylene glycol refining tower T101 is absolute pressure 20kPa, the theoretical plate number is 60, the reflux ratio is 10.7, and the tower kettle temperature is 149.6 ℃. 971.1kg/h, 99.98% (wt%) of ethylene glycol were obtained in the bottom of the column.
The operating pressure of the entrainer recovery tower T102 is 100kPa, the theoretical plate number is 45, the reflux ratio is 10.4, and the tower kettle temperature is 184.9 ℃.
The operation pressure of the butanediol removing tower T103 is 13kPa, the theoretical plate number is 45, the reflux ratio is 13.5, and the tower kettle temperature is 138.5 ℃. The column bottom gave 28.9kg/h, 99.8% (wt%) of 1, 2-butanediol.
The amount of diethyl oxalate for supplementing fresh entrainer is 0.02kg/h. The azeotropic agent recovery column contained 1, 2-butanediol in the azeotropic gas at the top of the column at a concentration of 25.0 (wt%). The overhead azeotrope of the debutanizer contained 1, 2-butanediol at a concentration of 14.1 (wt%).
Example 5
Using the flow chart shown in FIG. 1, a mixture 2 containing 96% by weight of ethylene glycol and 4% by weight of 1, 2-butanediol was fed into an ethylene glycol refining column T101 together with diethyl oxalate 5 as an entrainer at a flow rate of 1000 kg/h.
The operation pressure of the ethylene glycol refining tower T101 is absolute pressure 15kPa, the theoretical plate number is 65, the reflux ratio is 9.6, and the tower kettle temperature is 142.4 ℃. The bottom of the column yielded 960kg/h of 99.99% (wt%) ethylene glycol.
The operating pressure of the entrainer recovery tower T102 is absolute pressure 95kPa, the theoretical plate number is 50, the reflux ratio is 9.2, and the tower kettle temperature is 183 ℃.
The operation pressure of the butanediol removing tower T103 is 9kPa, the theoretical plate number is 50, the reflux ratio is 12, and the tower kettle temperature is 130.2 ℃. 40kg/h of 99.8% (wt%) 1, 2-butanediol were obtained in the column bottom.
The amount of diethyl oxalate for supplementing fresh entrainer is 0.02kg/h. The azeotropic agent recovery column contained 1, 2-butanediol in the azeotropic gas at the top of the column at a concentration of 24.7 (wt%). The overhead azeotrope of the debutanizer contained 1, 2-butanediol at a concentration of 12.3 (wt%).
Example 6
Using the flow chart shown in FIG. 1, a mixture 2 containing 96% by weight of ethylene glycol and 4% by weight of 1, 2-butanediol was fed into an ethylene glycol refining column T101 together with diethyl oxalate 5 as an entrainer at a flow rate of 1000 kg/h.
The operation pressure of the ethylene glycol refining tower T101 is 10kPa absolute pressure, the theoretical plate number is 70, the reflux ratio is 8.5, and the tower kettle temperature is 132.8 ℃. The bottom of the column yielded 960kg/h of 99.99% (wt%) ethylene glycol.
The operating pressure of the entrainer recovery tower T102 is absolute pressure 90kPa, the theoretical plate number is 55, the reflux ratio is 8.2, and the tower kettle temperature is 181 ℃.
The operation pressure of the butanediol removing tower T103 is 5kPa absolute pressure, the theoretical plate number is 55, the reflux ratio is 10.5, and the tower kettle temperature is 117.5 ℃. 40kg/h of 99.8% (wt%) 1, 2-butanediol were obtained in the column bottom.
The amount of diethyl oxalate for supplementing fresh entrainer is 0.02kg/h. The azeotropic agent recovery column contained 1, 2-butanediol in the azeotropic gas at the top of the column at a concentration of 24.4 (wt%). The overhead azeotrope from the debutanizer contained 1, 2-butanediol at a concentration of 9.6 (wt%).
The above embodiments are merely illustrative, not restrictive, and various modifications may be made without departing from the scope of the invention, which is intended to be covered by the claims.
Claims (7)
1. A process method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation is characterized in that: sending a mixture of ethylene glycol and 1, 2-butanediol and a entrainer diethyl oxalate to an ethylene glycol refining tower for separation and refining to obtain an ethylene glycol product, wherein the top of the tower is an azeotropic mixture of 1, 2-butanediol and diethyl oxalate, and then sending the azeotropic mixture to an entrainer recovery tower, the bottom of the entrainer recovery tower is used for recovering the diethyl oxalate as the entrainer and circulating the diethyl oxalate to the ethylene glycol refining tower, sending the azeotropic mixture of 1, 2-butanediol and diethyl oxalate at the top of the entrainer recovery tower to a butanediol removal tower, separating and refining the 1, 2-butanediol product at the bottom of the butanediol removal tower, and circulating the azeotropic mixture of 1, 2-butanediol and diethyl oxalate at the top of the butanediol removal tower to the entrainer recovery tower;
the operating pressure of the ethylene glycol refining tower is 2-35 kPa, the number of theoretical plates is 35-80, the reflux ratio is 5-14, and the temperature of a tower kettle is not more than 165 ℃;
the operating pressure of the entrainer recovery tower is 80-115 kPa, the theoretical plate number is 20-60, the reflux ratio is 5-14, and the temperature of a tower kettle is not more than 191 ℃;
the operating pressure of the debutanizer is 2-25 kPa absolute pressure, the number of theoretical plates is 20-60, the reflux ratio is 8-18, and the temperature of the tower kettle is not more than 155 ℃.
2. The process according to claim 1, characterized in that: the top gas of the entrainer recovery tower is used as a heat source of a reboiler of a butanediol removal tower kettle.
3. The process according to claim 1, characterized in that: after the heat exchange of the top gas of the entrainer recovery tower, one part of the top gas returns to the entrainer recovery tower to be used as reflux liquid, and the other part of the top gas is sent to the butanediol removal tower.
4. The process of claim 1, wherein: the device for realizing the method comprises an ethylene glycol refining tower, an entrainer recovery tower and a butanediol removing tower, wherein a tower kettle discharge port of the ethylene glycol refining tower is connected with an ethylene glycol refining tower kettle pump, an ethylene glycol product cooler and an ethylene glycol product tank through a pipeline; the outlet of the top of the ethylene glycol refining tower is connected with an ethylene glycol refining tower condenser, an ethylene glycol refining tower reflux tank and an ethylene glycol refining tower reflux pump through pipelines, the outlet of the ethylene glycol refining tower reflux pump is divided into two paths, one path is connected with the top reflux port of the ethylene glycol refining tower, the other path is connected with the inlet of an entrainer recovery tower, the outlet of the bottom of the entrainer recovery tower is connected with an entrainer inlet pipeline of the ethylene glycol refining tower through an entrainer recovery tower bottom pump, the outlet of the top of the entrainer recovery tower is connected with the shell pass inlet of the entrainer recovery tower condenser through a pipeline, the shell pass outlet of the entrainer recovery tower condenser is connected with the entrainer recovery tower reflux tank and the entrainer recovery tower reflux pump, the outlet of the reflux pump of the entrainer recovery tower is divided into two paths, one path is connected to the top reflux port of the entrainer recovery tower, the other path is connected to the feed inlet of the butanediol removing tower, the discharge port at the top of the butanediol removing tower is connected with a butanediol removing tower condenser, a butanediol removing tower reflux tank and a butanediol removing tower reflux pump through pipelines, the outlet of the butanediol removing tower reflux pump is divided into two paths, one path is connected to the top reflux port of the butanediol removing tower, the other path is connected to the feed inlet of the entrainer recovery tower, and the discharge port at the bottom of the butanediol removing tower is connected with a butanediol removing tower kettle pump, a 1, 2-butanediol product cooler and a 1, 2-butanediol product tank through pipelines.
5. The method of claim 4, wherein: and the tower kettle of the butanediol removing tower is connected with a butanediol removing tower supplement reboiler.
6. The method of claim 4, wherein: the condenser of the entrainer recovery tower is simultaneously used as a reboiler of the butanediol removing tower, and the inlet and the outlet of the condenser tube pass of the entrainer recovery tower are respectively connected with the tower kettle of the butanediol removing tower.
7. The method of claim 4, wherein: the ethylene glycol refining tower, the entrainer recovery tower and the butanediol removal tower are one or a combination of a plate tower, a bulk packed tower or a regular packed tower.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011421049.6A CN112538002B (en) | 2020-12-08 | 2020-12-08 | Process method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011421049.6A CN112538002B (en) | 2020-12-08 | 2020-12-08 | Process method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112538002A CN112538002A (en) | 2021-03-23 |
| CN112538002B true CN112538002B (en) | 2023-03-21 |
Family
ID=75018264
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011421049.6A Active CN112538002B (en) | 2020-12-08 | 2020-12-08 | Process method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112538002B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114797145B (en) * | 2022-05-05 | 2022-12-06 | 河北工业大学 | Differential pressure thermal coupling rectification process for coal-to-ethylene glycol byproduct |
| CN115141081B (en) * | 2022-07-18 | 2024-01-23 | 常州大学 | Method for separating azeotrope ethylene glycol and ethylene glycol diacetate based on azeotropic distillation mode |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103396290A (en) * | 2013-07-08 | 2013-11-20 | 吉林化工学院 | Novel process for separating ethylene glycol and 1,2-butanediol |
| CN103664522A (en) * | 2012-09-05 | 2014-03-26 | 中国石油化工股份有限公司 | Method with heat integration function for separating ethylene glycol from 1,2-butylene glycol |
| CN104926608A (en) * | 2014-03-17 | 2015-09-23 | 中国石油化工股份有限公司 | Method for separating ethylene glycol and 1,2-butanediol |
| CN108017517A (en) * | 2017-12-29 | 2018-05-11 | 华东理工大学 | Using the method for azeotropic distillation separating low concentration 1,2- butanediols from ethylene glycol |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3126315B1 (en) * | 2014-04-02 | 2018-06-13 | Shell International Research Maatschappij B.V. | Process for the separation of monoethylene glycol and 1,2-butanediol |
-
2020
- 2020-12-08 CN CN202011421049.6A patent/CN112538002B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103664522A (en) * | 2012-09-05 | 2014-03-26 | 中国石油化工股份有限公司 | Method with heat integration function for separating ethylene glycol from 1,2-butylene glycol |
| CN103396290A (en) * | 2013-07-08 | 2013-11-20 | 吉林化工学院 | Novel process for separating ethylene glycol and 1,2-butanediol |
| CN104926608A (en) * | 2014-03-17 | 2015-09-23 | 中国石油化工股份有限公司 | Method for separating ethylene glycol and 1,2-butanediol |
| CN108017517A (en) * | 2017-12-29 | 2018-05-11 | 华东理工大学 | Using the method for azeotropic distillation separating low concentration 1,2- butanediols from ethylene glycol |
Non-Patent Citations (2)
| Title |
|---|
| 乙二醇-1，2-丁二醇汽液相平衡及分离的研究;朱连天;《中国优秀硕士学位论文全文数据库 (工程科技Ⅰ辑)》;20120715;全文 * |
| 生物质化工醇中乙二醇和;杨颜如 等;《现代化工》;20181130;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112538002A (en) | 2021-03-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112538002B (en) | Process method for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation | |
| CN101978028B (en) | Separation process for olefin production | |
| CN102164880B (en) | The high-energy in the dehydrogenating propane device of high pressure product splitter tower is utilized to reduce | |
| CN1096440C (en) | Improved chemical absorption process for recovering olefins from cracked gases | |
| JPH07206745A (en) | Separating method for oxygen-containing compound from hydrocarbon comprising distillation and transmission and its method by etherification | |
| CN101348412B (en) | Energy-saving method for phenyl ethylene rectification | |
| JPH01165539A (en) | Pervaporation for separating alcohol from ester | |
| KR101662895B1 (en) | Purification method of isopropyl alcohol | |
| CN107253901A (en) | A kind of separation of high-purity isopropanol and purification method | |
| CN101033170A (en) | Process for dewatering of ethanol | |
| RU2574729C2 (en) | Method for purification of mtbe-containing mixtures and obtaining isobutylene by cleavage of mtbe-containing mixtures | |
| CN214105872U (en) | Process unit for separating ethylene glycol and 1, 2-butanediol by azeotropic distillation | |
| CN114797145B (en) | Differential pressure thermal coupling rectification process for coal-to-ethylene glycol byproduct | |
| CN101633597B (en) | Method for saving energy in rectification of styrene | |
| CN113636903B (en) | Method for preparing triisobutene by oligomerization of isobutene | |
| CN107057752B (en) | A kind of method of lighter hydrocarbons deeply de-aromatizing | |
| CN216129524U (en) | Separation refining plant for preparing methyl acetate from industrial tail gas | |
| CN112479869B (en) | Method for rectifying dimethyl oxalate in coal chemical industry | |
| CN105647583A (en) | Novel absorption stabilizing technology and system | |
| RU2368593C1 (en) | Method of extracting isobutylene | |
| CN209940867U (en) | Production system of high-purity 1, 4-butanediol | |
| CN218980483U (en) | Purification device of Fischer-Tropsch synthesized normal alkane olefin and high-purity hydrocarbon production system | |
| JP5920120B2 (en) | Propylene production method | |
| CN106187664B (en) | The method for preparing isobutene | |
| CN114591144B (en) | Tower type isopropanol solution adsorption, rectification, separation and purification method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |