At present, LNG cold energy utilization includes air separation, light hydrocarbon separation, power generation, refrigeration, etc., In air separation, the temperature region is close to each other, and the high-grade cold energy of LNG cooling can get high value.Air separation is mainly used to produce liquid oxygen, liquid nitrogen and liquid argon. Compared with the traditional air separation process, it saves 50% electricity, saves 90% water and has less carbon emissions.
Air separation system mainly includes filter compression system, air purification system, air separation distillation system, LNG heat exchanger cold box system, low-temperature liquid storage system, Coolant cooling system and nitrogen pipe network system. The interstage and final stage coolers of air compressors are cooled by Glacier Coolant as coolant.Air compressors and oil coolers use reheated Glacier Coolant to continue cooling.The heated Glacier Coolant is then cooled by centrifugation by pumping to a lower LNG heat exchanger to cycle cooling.
The cooling capacity of air separation unit is generally provided by liquid nitrogen.The high-pressure nitrogen is liquefied in the LNG-nitrogen heat exchanger, throttled to medium pressure and reduced liquid nitrogen temperature again , partially stored in the total pressure liquid nitrogen tank, partially throttled again and stored in the pressure liquid nitrogen tank. The pressure liquid nitrogen enters the liquid nitrogen separation heat exchanger, high-pressure nitrogen is liquefied, and the vaporized pressure nitrogen enters the low-temperature circulating nitrogen compressor to transfer the LNG cold energy to the air separation system.the heat exchange temperature of LNG-nitrogen heat exchanger is-120℃, divided into three pressure intervals, vaporized by different pressure, compression cycle.This process uses nitrogen as an inert gas,The heat transfer process is mainly nitrogen cycle, the system is more efficient and safe.
The pressurized low-temperature LNG is transported to the LNG-nitrogen heat exchanger through pipelines, part of it is directly vaporized to the NG pipe network, part of it is used to cool coolant, and also to the ng pipe network after vaporization.The utilization efficiency and technology of air separation system can be improved in theory.More technicians are needed to explore and improve LNG gasification air separation projects.
Glacier Coolant focuses on Coolantt, and will continue to focus on and study LNG gasification air separation system.