Acetylene Recovery
Linde's acetylene recovery is based on the extraction of acetylene with DMF (Dimethylformamide), and is accepted by the industry as the leading technology for acetylene recovery, which has been installed even in new ethylene plants of competitors with own acetylene technology.
The average content of acetylene in the furnace effluent stream of an ethylene plant is in the range of 0.3 to 0.9 % by weight. Liquid feedstocks, such as light naphtha, and high cracking severities favour high acetylene yields.
The basic arrangement of the Linde process for the recovery of high purity acetylene includes three major steps:
Basic Flow Diagram: Acetylene Recovery
1. Acetylene Absorption
In an absorber column, the gas stream is contacted with counterflowing lean DMF and all acetylene and some ethylene and ethane are dissolved by the DMF. A subsequent separator reduces the concentration of ethylene.
2. Ethylene Stripping The solvent stream leaving the separator still contains some traces of ethylene. This is stripped off in an absorption column.
3. Acetylene Stripping The stream leaving the ethylene stripper now consists of DMF and dissolved acetylene only. The stream is heated by means of cooling the regenerated DMF stream and is fed to an acetylene stripping DMF regeneration column. The acetylene product leaves the unit at 0.1 barg and ambient temperature. The purity of the product is higher than 99.9 % with a DMF content in the product of less than 50 ppm.
Example
Customer:
Quantum USt Division
Plant location:
Deerpark, Texas/USA
Process:
Linde extraction process within an ethylene plant
Capacity:
1,057,000 MTA ethylene and ethane stream purified to final acetylene specification
Product:
14,400 MTA high purity acetylene
Scope of work:
Process design, basic engineering, detail engineering, equipment procurement, start-up supervision, LINDE proprietary hardware
Start-up:
1991
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