Research On Operation Optimization Of A Natural Gas Cryogenic Processing Plant

In Daqing Oilfield,there is a natural gas processing plant whose feedstock is associated natural gas with propane plus recovered in several propane recovery plants,which is designed to recover more natural gas liquids and to increase cryogenic processing ration of associated natural gas in the north part of the oilfield.This natural gas processing plant was put into operation in 2013 with the designed processing capacity of 1.4 million stand cubic meters.It has a designed natural gas liquids recovery ratio of 0.78 ton per 10,000 stand cubic meters,whose natural gas liquids recovery ratios of practical operation in 2014 and 2015 were much lower than that.Guided by modern theory and methods in natural gas processing and based on the detailed research study on principles and processes of cryogenic process,this paper borrowed ideas from advanced experiences in relative research both domestic and abroad,and provide a more optimized operation plan after analyzing its running data,studying its process,making many comparison and simulating with software.Based on the research results,this paper provides some suggestions on operation optimization,which are(1)its natural gas liquids recovery ratio can increase 0.1249 ton per 10,000 stand cubic meters by optimizing the sources of its feedstock and improving propane plus content in the feedstock,which will be achieved after reforming the pipeline network;(2)its natural gas liquids recovery ratio can increase 0.0398 ton per 10,000 stand cubic meters by stopping the refrigeration unit in A propane recovery plant and the total energy consumption with come down;(3)the operation cycle in molecular sieves dehydration unit can be lengthened to decrease energy consumption because the molecular sieves paced in the cryogenic plant is much more than that need according to current operation cycle;(4)the total energy consumption in the cryogenic plant can be reduced by lowing gas stream temperature cooled after 1 stage air cooler and after air cooler in outlet of co-axially compressor and recovering cooling capacity in gas leaving the plant.