Integrated Process Design and Optimization of Nitrogen Recovery in Natural Gas Processing

Recently in natural gas processing, with various feed gases from small to midsize gas reservoirs or shale gas and new compressor drivers of high efficiency that require less or no fuel gas, there has been a growing need of sophisticated nitrogen recovery solutions in producing LNG (liquefied natural gas). In this study two cryogenic nitrogen recovery processes integrated with NGL (natural gas liquid) recovery and LNG production are designed and optimized on the basis of structural analysis of component separation. The difference of each process is the way the nitrogen is removed from the natural gas: an integrated nitrogen recovery unit (NRU) and a standalone one. The former recovers nitrogen in the integrated heat and mass transfer structure with natural gas liquefaction while the latter separates the NRU into an independent section apart from the liquefaction part. These two processes …