Recovery of Ethylene from Catalytic Cracking Dry Gas

The first unit for the recovery of ethylene from catalytic cracking dry gas in China has recently started production in Refinery of Beijing Yanshan Petrochemical Company Ltd. China has a catalytic cracking capacity of 93 million t/a today. Around 4.14 million tons of catalytic cracking dry gas is produced a year. It contains 730 000 tons of ethylene, 720 000 tons of ethane, 110 000 tons of propylene, 40 000 tons of butene, 110 000 tons of alkanes such as propane and butane and 110 000 tons of hydrogen.       The technology for the recovery of ethylene from catalytic cracking dry gas has been widely used in China. 4.15 million tons of light oil used in the ethylene production can be saved a year. Based on a light oil yield of 73%, the crude oil processing amount can be reduced by 5.68 million tons a year.       The process technology used in the unit is jointly developed by Sinopec Beijing Yanshan Petrochemical Company Ltd. and Sichuan Tianyi Science & Technology Co., Ltd. It uses pressure swing adsorption, wet-process desulfurization and decarbonization, hydrodeoxidation and alumia/molecular sieve drying to recover heavy olefins such as ethylene, ethane and propylene and use them as raw materials for the separation section of the ethylene cracking unit.