Device and method for separating C2 and C3-rich dry gas from NMP (N-Methyl Pyrrolidone)

The invention belongs to the technical field of refinery dry gas recovery, and provides a device and a method for separating C2 and C3-rich dry gas from NMP (N-Methyl Pyrrolidone). After the refinery dry gas is compressed and cooled, NMP and recovered light hydrocarbon heavy components are used as absorbents to absorb the dry gas twice, the two rich absorbents absorbing the components in the dry gas are regenerated and circulated in a mode of flash evaporation and thermal desorption, flash evaporation is performed in two steps of high-pressure flash evaporation and low-pressure flash evaporation, and the high-pressure flash evaporation and the low-pressure flash evaporation are performed in two steps of high-pressure flash evaporation and low-pressure flash evaporation. And finally, C3-rich gas is obtained at the top of the C3 desorption tower, and C2-rich gas is obtained at gas phase outlets of the two low-pressure flash evaporation areas and the top of the heavy component recovery tower. The process disclos