Plants ethylene, purification system

Feed ethylene is normally delivered to the plant by a pipeline grid or directly from a cracker on the same site. As the process is highly sensitive to impurities, sulphin compoimds, acetylene and other impurities are removed from the feed ethylene by purification beds. The cleaned feed ethylene is then compressed to the required reaction pressure and enters the reactor loop at the bottom of the reactor. A metal oxide catalyst, alinniniinn alkyl in hydrocarbon as a cocatalyst, lower olefins as comonomers and other auxihary chemicals are fed directly into tire reactor loop. Typically, different product types can be produced by selecting the catalyst system, the comonomers and the reaction conditions. 

Air-Based Direct Oxidation Process. A schematic flow diagram of the air-based ethylene oxide process is shown in Figure 2. Pubhshed information on the detailed evolution of commercial ethylene oxide processes is very scanty, and Figure 2 does not necessarily correspond to the actual equipment or process employed in any modem ethylene oxide plant. Precise information regarding process technology is proprietary. However, Figure 2 does illustrate all the saUent concepts involved in the manufacturing process. The process can be conveniently divided into three primary sections reaction system, oxide recovery, and oxide purification. 

The fragmentation of ACPC (9) that leads to ethylene (139) is at least as remarkable, occurs in a much less well-characterized system (plant mitochondria) that has resisted purification, and has been mechanistically unobvious. 

Refrigeration systems are extensively used in the chemical industries in low temperature processes such as liquefaction of natural gas, ethylene purification and cryogenic air separation. In these kinds of low temperature systems, heat is rejected from the process by refrigeration to heat sinks being other process streams or refrigeration systems at the expense of mechanical work. The refrigeration systems employed are complex, and energy and capital intensive, and therefore, play a critical role in the overall plant economics. 

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