ENERGY-SAVING PROCESS AND APPARATUS FOR RECOVERING C2 FROM REFINERY DRY GAS

摘要

An energy-saving process and apparatus for recovering C2 from refinery dry gas. The procedure of the process comprises: cooling dry gas, and then delivering same to a multistage absorption tower for treatment; delivering a gas phase of the multistage absorption tower to a fuel gas pipe network or a PSA apparatus, and delivering a liquid phase thereof to a high-pressure flash evaporation zone for treatment; a gas phase of the high-pressure flash evaporation zone being returned to a compression section of a dry gas pretreatment system, part of a liquid phase thereof serving as a semi-lean solvent and circularly being returned to the multistage absorption tower, and part of the liquid phase entering a low-pressure flash evaporation zone for treatment; delivering a gas phase of the low-pressure flash evaporation zone to a C2 concentrated gas compressor system, part of a liquid phase thereof serving as a secondary lean solvent and circularly being returned to the multistage absorption tower, and delivering part of the liquid phase to a desorption tower for treatment; and a gas phase of the desorption tower being mixed with the gas phase obtained in the low-pressure flash evaporation zone to serve as a C2 concentrated gas product, delivering the C2 concentrated gas product to an ethylene apparatus cracking furnace, most of a liquid phase thereof serving as a lean solvent and being returned to the multistage absorption tower, and the rest of the liquid phase serving as extracted C4 and being delivered to the outside. The process of the present invention has the following advantages: same has a simple flow, the usage amount of lean solvents and energy consumption are greatly reduced, same requires a small investment, has a high C2/C3 recovery rate, etc.