PROPANE PRECOOLING CYCLES FOR INCREASED LNG TRAIN CAPACITY

摘要

As a result of the growth of LNG markets, the LNG production capacity of liquefaction trains is increasing continuously. This is true not only for new projects, but also for the debottlenecking of existing trains. rnThis tendency can be expected to continue for some years rnWhen the refrigerant compressors and in particular the propane compressor are gas turbine driven the propane pre-cool refrigerant cycle must overcome the limitations of its compressors and drivers. The compressors of the liquefaction mixed component refrigerant cycle also pose some technical problems. rnTo identify solutions that are reliable yet sufficiently innovative, TECHNIP has undertaken studies to surpass the previously identified limits for propane pre-cooled LNG trains. The following aspects were studied: rn1. Optimisation of the composition of the mixed refrigerant to facilitate the design of the propane cycle rn2. Optimisation of the use and design of the pre-cooling cycle rn3. The use of propane compressors made up of two casings rn4. Optimisation of the choice of the propane compressor gas turbine driver: GE Frame 5, 6, 7 and 9. rnThe studies were based on gas from the Qatar North Field and the use of the liquefaction process where a mixed component refrigerant is pre-cooled by another refrigerant made up of propane.