Dynamic Characteristic And Offshore Adaptability Of FLNG Liquefaction Process

FLNG is a floating production unit which sets the exploration,pretreatment,liquefaction,storage,load and unload as a whole.The natural gas liquefaction process is a core technology of FLNG,which has a huge impact on the safety,stability and costs of the equipment.Because of the special conditions of offshore operations,FLNG liquefaction process is requirednot only to achieve the most basic functions of liquefaction,it is also expected to overcome the interference of various constraints.Through an investigation into FLNG technical studies,preliminary election Pre-cooling Dual Nitrogen Expander Liquefaction Processes and Dual mixed Refrigerant Liquefaction Processes,the paper combines experimental results and simulation results to test the dynamic characteristics and offshore adaptability of liquefaction process,and provides evidence and guidance for the selection of FLNG liquefaction process.Firstly,an experimental deviceof Propane Pre-cooling Dual Nitrogen Expander Liquefaction Processes is established,five kinds of experiments including normal performance testing,control scheme verification,abnormal conditions testing,sloshing adaptability and refrigeration systems have been operated independently,andthe adaptability of liquefaction process is tested.Then,the paper compares experiment results with dynamic simulation results to verify the accuracy of dynamic simulation models,and also makes sensitivity analysis of propane pre-cooled dual nitrogen expander liquefaction process with the dynamic simulation models.Secondly,an experimental deviceof Dual mixed Refrigerant Liquefaction Processes is established,and three kinds of experiments including flow rate and cooling temperature of feed gas,changing the frequency of the compressor are made.Then,the paper also compares experiment results with simulation results to verify the accuracy of simulation models,and uses simulation model to predict the results of Dual mixed Refrigerant Liquefaction Processes on the pilot plant and the sensitivity analysis of liquefaction process.Thirdly,the offshore adaptability of Pre-cooling Dual Nitrogen Expander Liquefaction Processes and Dual mixed Refrigerant Liquefaction Processes(The main sloshing equipment is Splitter and heat exchanger)has been studied with dynamic simulation models.The comparison of dynamic characteristic of liquefaction process(the temperature,pressure of feed gas and cooling temperature of compressor),and exergy analysis of liquefaction process is also performed.The study shows that Propane Pre-cooling Dual Nitrogen Expander Liquefaction Processes has a strong anti-shake performance,high security,smooth running performance,strong anti-disturbance performance and great offshore adaptability.The exergy loss of liquefaction is 18.09% higher than that of Dual mixed Refrigerant Liquefaction Processes.After comprehensive consideration of investment,energy consumption,reliability,security and offshore adaptability,it indicates that Pre-cooling Dual Nitrogen Expander Liquefaction Process is more suitable for offshore FLNG liquefaction plant.