CB&I's Acetylene Recovery Technology is a solvent based liquid absorption process designed to recover high purity acetylene from the mixed C2 stream in an ethylene plant. Typically the C2 acetylene in an ethylene plant is selectively hydrogenated to ethylene and recovered as PG ethylene product. In some instances when there is downstream use of acetylene or acetylene is required as a by-product stream, the Acetylene Recovery process is integrated with the ethylene plant. Feed is taken from the deethanizer overhead and once the acetylene is recovered the remaining ethylene and ethane is returned to the cracker at the ethylene fractionator. This can be done on a grassroots design or as part of a retrofit after the cracker has been put into operation. The technology produces high purity acetylene, typically 99.6 mol%, and offers a higher recovery rate of the acetylene contained in the feed. As such it can eliminate or replace the acetylene hydrogenation system in the ethylene plant.
CB&Is Acetylene Recovery Technology uses dimethylformamide (DMF) as its solvent. Of the available solvents, DMF offers superior performance due to its high selectivity to acetylene and low co-absorption of ethylene. The use of DMF thereby achieves high acetylene recovery and low ethylene loss. It is a widely available and low-cost solvent which minimizes operating costs. The process is highly-integrated with the ethylene plant and this integration minimizes solvent carryover with the acetylene product and minimizes energy consumption. The integration also minimizes plant investment, offering the lowest capital costs. The safety risks of acetylene decomposition are minimized by the use of proprietary design standards for the vessels, piping and operating conditions in sections of the unit where the acetylene concentration is high enough to lead to decomposition.