Alternative Thermal Coupled Process for Vacuum Induced Air for Ethylene Glycol Distillation Separation

A technology for rectification separation and ethylene glycol, which is applied in heat exchangers, chemical industry, indirect heat exchangers, etc., can solve problems such as affecting the stability of heat pump system operation, difficulty in control system design and operation, and fluctuations in boiling point difference.

Active Publication Date: 2022-06-07
SHANGHAI JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Patent CN104788289A proposes to use heat pump rectification in the de-butanol tower, but there are the following problems: first, the glycol vapor at the top of the tower cannot be directly compressed, and an indirect heat pump is required, and the temperature of the water vapor generated by the latent heat of the glycol vapor is lower than that at the top of the tower Compared with the direct heat pump, it requires a larger compression ratio and power consumption; secondly, the number of theoretical plates in the debutanol tower is large, and it is difficult to avoid obvious fluctuations in the pressure difference between the top and the bottom of the tower during operation. Therefore, the difference fluctuates significantly, which affects the stable operation of the heat pump system. Under the premise of effective operation and regulation of the tower, more complex control design is required to avoid surge or choking of the heat pump compressor.
It is also necessary to consider the obvious pressure difference between the top and the bottom of the tower due to the large number of theoretical plates. Therefore, the available heat transfer temperature difference between the top of the high-pressure debutanol tower and the bottom of the low-pressure debutanol tower is very small, and it is only suitable for two-effect Distillation, recycling equipment with less than half of the energy consumption is a huge investment
[0007] The compressors or towers added by the above-mentioned heat pump and multi-effect rectification are difficult to operate and control. Coupling the heat load adjustment operation status of the top of the high-pressure debutanol tower and the bottom of the low-pressure debutanol tower brings greater difficulties in the design and operation of the control system, hindering the practical application of these energy-saving technologies application

Method used

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  • Alternative Thermal Coupled Process for Vacuum Induced Air for Ethylene Glycol Distillation Separation
  • Alternative Thermal Coupled Process for Vacuum Induced Air for Ethylene Glycol Distillation Separation
  • Alternative Thermal Coupled Process for Vacuum Induced Air for Ethylene Glycol Distillation Separation

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Embodiment 1

[0039] as Figure 2As shown, the stream strand S80 extracted from the bottom of the deoxate tower enters the debutanol tower T3, Debutanol tower T3 top pressure 0.4atm, temperature 162 °C, debutanol tower T3 top of the binary alcohol steam S1 has been connected in series coupling heat exchanger E-C and condenser E1 to achieve full condensation, condenser E1 uses circulating water CWI to ensure the cooling load of the top of the debutanol tower and meet the cooling load required for operation process regulation, coupling heat exchanger E-C and condenser E1 generated by the condensate into the condensate storage tank B1, the extraction of mixed diol product S14, the rest of the S13 backflow to the top of the debutanol tower T3, debutanol tower T3 bottom to extract flow stockS11 into the ethylene glycol refining tower T4 , ethylene glycol refining tower T4 top pressure 0.1atm, with liquid side line S15 to extract the product ethylene glycol S15, to the top steam flow S17 to extract th...

Embodiment 2

[0047] as Figure 3As shown, the condensing liquid product FEED from the oxalate hydrogenation reaction section has a temperature of 90 °C and enters the dehydration tower T1 after passing through the coupling heat exchanger E-CA, Dehydration tower T1 top pressure 0.6atm, dehydration tower T1 top extraction of water and methanol and other light components of the shunt strand S20, dehydration tower T1 bottom stream S19 into the deoxate tower T2, deoxate tower T2 top pressure 0.5atm, deoxate tower T2 top extraction mainly for oxalate and methyl glycolate flow strand S18, bottom of the tower extracted flow strand S80 into the debutanol tower T3, debutantol tower T3 top pressure 0.4atm, temperature 162 °C, debutantol tower T3 tower top of the binary alcohol vapor is divided into parallel S1 and S1A two parts, respectively through the coupling heat exchanger E-C and coupled heat exchanger E-CA , coupling heat exchanger E-C uncoated steam S2 and coupled heat exchanger E-CA uncoated steam...

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Abstract

The invention relates to a vacuum-induced draft thermal coupling process for rectification and separation of ethylene glycol, in which a vacuum system is used to guide the coupling of glycol steam (S1) at the top of the debutanol tower with the heated stream (S5) Heat exchange; the pressure of the glycol steam (S1) is 0.2-0.6bar, and it is realized through the coupling heat exchanger (E-C) and condenser (E1) connected in series successively to fully condense, wherein the condenser (E1) The shell side is far away from the top position of the glycol vapor inlet to connect the vacuum system (P1), guide the flow of the glycol vapor through the vacuum system (P1), and adjust the pressure at the top of the debutanol column; the heated stream (S5) Divided into two parts connected in parallel, heated by coupling heat exchanger (E‑C) and heater (E2) respectively. Compared with the prior art, the present invention adopts a vacuum system to guide the diol steam at the top of the debutanolization tower to the adjacent tower to couple with the heated stream for heat exchange, which does not require steam conveying machinery and is convenient for control operation.

Description

Technical field [0001] The present invention relates to the field of chemical production technology, specifically to a process method of thermal coupling energy saving in the process of ethylene glycol distillation separation. Background [0002] At present, there are several sets of industrial-scale units operating from syngas to produce ethylene glycol, using CO oxidation coupling to form oxalate, and then oxalate is hydrogenated to produce ethylene glycol. The process product introduced low-grade carboxylic acid and its esters, propylene glycol, butanediol and other impurities, to the ethylene glycol distillation separation increased a great difficulty, ethylene glycol distillation separation system at least needs dehydration tower, deoxalate tower, debutyl alcohol tower and ethylene glycol refining tower, of which ethylene glycol and 1,2-butanediol boiling point is close, separation is difficult, the energy consumption of the debutyl alcohol tower accounts for about 40% of th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C31/20C07C29/80F28D21/00F28F27/02
CPCC07C29/80F28D21/0014F28F27/02C07C31/202Y02P20/50
Inventor 阎建民肖文德李学刚罗漫
Owner SHANGHAI JIAOTONG UNIV
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