Small Scale Split Flow Integrated LNG Production Process (SFI-LNG)

A novel split flow integrated LNG production process (SFI-LNG) is developed and optimized in order to significantly reduce power consumption of small-scale LNG production plant which make small-scale LNG plant more efficient and also more environmentally friendly process with lower CO₂ emission.

The main core of SFI-LNG process comprises two fundamental sections: natural gas (NG) purification and NG liquefaction. Compared to a conventional NG liquefaction processes, SFI-LNG process can provide opportunities to economize on number of equipment, for example by using two stages of coil-wound heat exchange instead of three stages and also with lower operation pressure.

No conventional NG treating nor dehydration processes as an objective function is defined in design of NG purification section. In order to prevent the CO₂ freezing in the NG liquefaction exchangers, CO₂ content must be reduced from 3mol% to less than 50ppm. Part of the invention cryogenic CO₂ removal process has developed and can purify dried natural gas at cryogenic temperature by utilizing a new nanoparticle packed column as a physical adsorption bed.

The power consumption as an objective function is optimized with key parameters and the optimization results show that the NG liquefaction section can provide for significant reductions in total power consumption by up to 13.2% compared to conventional technologies. This in turn, the mass flow of mixed refrigerant cycle (MR) can be reduced compared to conventional processes by up to 16.1%. In particular, in conventional propane-mixed refrigerant cycle (C3-MR) processes, pre-chilling by propane is typically required, however, in SFI-LNG process, no pre-chilling is required and the mass flow of propane refrigerant loop can be smaller than in conventional installations by up to 18.8%.