HYDROCARBON GAS PROCESSING

摘要

A process and an apparatus are disclosed for the recovery of ethane, ethylene, propane, propylene, and heavier hydrocarbon components from a hydrocarbon gas stream. The stream is cooled and divided into first and second streams. The first stream is further cooled to condense substantially all of it and is thereafter expanded to the fractionation tower pressure and supplied to the fractionation tower at an upper mid-column feed position. The second stream is expanded to the tower pressure and supplied to the column at a mid-column feed position. A distillation vapor stream is withdrawn from the column above the feed point of the first stream, combined with a portion of the tower overhead vapor stream, compressed to higher pressure, and directed into heat exchange relation with the remaining tower overhead vapor stream to cool the compressed combined vapor stream and condense at least a part of it, forming a condensed stream. At least a portion of the condensed stream is expanded to the tower pressure and directed to the fractionation tower as its top feed. The quantities and temperatures of the feeds to the fractionation tower are effective to maintain the overhead temperature of the fractionation tower at a temperature whereby the major portion of the desired components is recovered.