【Ethylene Question Bank】What are the separation processes used in ethylene production? What are their respective features?
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This post was last edited by Guan Gongyu on 2016-3-19 at 13:34. bg9.png What are the separation processes for producing ethylene? What are their respective features? Reply to see the answer! What are the separation processes for producing ethylene? What are their respective features? (1) Sequential separation process: Companies that use the sequential separation process include Lummus and KBR; the former employs a low-pressure demethanization process, while the latter uses a high-pressure demethanization process. The technical features of their latest processes are as follows: a Technical features of Rums Company’s sequential separation process: ① Use of SRT-Ⅵ type cracking furnaces ； ②Five-stage pyrolysis gas compression, three-stage outlet alkaline washing ； ③Sequential separation of front-end low-pressure demethanization ； ④Back-end hydrogenation ； ⑤Dual-tower dual-pressure propane removal ； ⑥Cyanopropene hydrogenation uses catalytic distillation ； ⑦Low-pressure propylene distillation, forming a heat pump with the propylene chiller. b Technical features of KBR’s sequential separation process: ① Use of millisecond furnaces ； ②Five-stage pyrolysis gas compression, four-stage outlet alkali washing ； ③Sequential separation of high-pressure demethanization at the front end ； ④Back-end hydrogenation ； ⑤Between the compressor stages of the pyrolysis gas system, integrated inter-stage heat exchangers and suction tanks with a special structure are used. (2) Front-end deethanization process: Companies that use the front-end deethanization process include German company Linde and American company KBR. The former also uses a pre-deethanization process for liquid feedstocks, while the latter uses it only when cracking ethane. a Technical features of Linde’s front-end deethanization process: ① Use of Pyrocrack 1-1 or Pyrocrack 2-2 type cracking furnaces ； ②Isothermal hydrogenation of acetylene at the front end, deethanization at the front end ； ③Dual-tower dual-pressure deethanization ； ④Five-stage compression of pyrolysis gas, alkali washing at the outlet of the fourth stage ； ⑤The ethylene column is fed with a single stream, forming an open-cycle heat pump together with the ethylene chiller. b Technical features of KBR’s front-end deethanization process: ① Front-end heat-pump deethanization, adiabatic hydrogenation of acetylene and propyne at the front end ； ②Low-pressure demethanization ； ③Low-pressure ethylene distillation and formation of an open-loop heat pump with the ethylene plant ； ④Low investment required ； ⑤Four-stage compression of pyrolysis gas. (3) Pre-depropanization process: Companies that use the pre-depropanization process include Stone-Webster in the United States and KBR. a Technical features of the former depropanization process at Stone-Webster Company: ① Use of USC-type cracking furnaces ； ②Propane removal via dual towers and dual pressures at the front end, acetylene hydrogenation at the front end ； ③Five-stage compression of pyrolysis gas, four-stage outlet alkaline washing ； ④ARS technology and a pre-methanation tower are employed ； ⑤Low-pressure ethylene distillation with multiple feed streams; the ethylene distillation and the ethylene chiller form an open-loop heat pump. b Technical features of KBR’s former depropanization process: ① Use of GK-V type cracking furnaces from KTI Company ； ②Propane removal via dual towers and dual pressures at the front end; hydrogenation of acetylene and propyne at the front end ； ③Four-stage compression of pyrolysis gas, alkali washing at the three-stage outlet ； ④Low-pressure distillation of ethylene and formation of an open-loop heat pump with an ethylene chiller ； ⑤Low investment. (4) Topkin progressive separation process: The Topkin progressive separation process is also a type of sequential separation process; Dexinib Company uses this technology, and its features are as follows: ① It employs the GK-V type cracking furnace manufactured by KTI Company ； ②Medium-pressure double-column demethanization ； ③Dual-tower depropanization. @ylb913 @yanran88 @xutaotao @zhangqi1234 @68ZCW @cjhti @liuquan1100 @yan*aoyong @maysee @yame1996
The separation process of ethylene plants consists of two main parts: hydrogenation and cryogenic separation. Hydrogenation can be further divided into pre-hydrogenation and post-hydrogenation, while the separation processes can be categorized as sequential separation processes, pre-ethane removal processes, and pre-propane removal processes
The separation process of ethylene plants consists of two main parts: hydrogenation and cryogenic separation. Hydrogenation can be further divided into pre-hydrogenation and post-hydrogenation, while the separation processes can be categorized as sequential separation processes, pre-ethane removal processes, and pre-propane removal processes. Differences among the three processes: (1) The arrangement of the distillation columns is different: (due to varying suitability of the feed materials). In the sequential separation process, the columns are arranged in order based on the number of carbon atoms in the components, specifically: 1) Demethanizer, 2) Deethanizer, 3) Depropanizer. That is, in this process, C1, C2, and C3 are removed one after another in sequence. The order is abbreviated as [1 2 3]. The sequence of the pre-deethanization process is [2 1 3]. The sequence of the pre-depropanization process is [3 1 2]. (2) The location of hydrodeacetylation differs: Hydrodeacetylation carried out before the demethanization column is called pre-hydrogenation. Hydrodeacetylation carried out after the demethanizer is called post-hydrogenation. (3) Different cold box locations
It includes two parts: hydrogenation and cryogenic separation
It includes two parts: hydrogenation and cryogenic separation
Now, the optimization of various processing technologies is almost complete, and the differences between these processes are not significant anymore
Looking at the ethane to ethylene production process......
Pre-depropanization hydrogenation, SW, SEI; dual-tower dual-pressure depropanization at the front end; acetylene hydrogenation at the front end; ethylene distillation and ethylene refrigeration using an open-cycle heat pump; pre-demethanization. Sequential process: Rums, front-end low-pressure demethanization, low-pressure propylene distillation, and formation of a heat pump in conjunction with the propylene unit ； KBR, front-end high-pressure demethanization. (Rear-end hydrogenation) Pre-deethanization, Linde, two-tower dual-pressure deethanization ； KBR, front-end heat pump deethanization. Wait