Simulation And Analysis Of Small Scale Natural Gas Liquefaction Processes

Natural gas is a kind of high-quality, efficient, clean new energy compare with coal and oil. it has been more and more concerned and paid attention by people. China has abundant natural gas reserves, and natural gas processed into liquefied natural gas (LNG). It is more conductive to storage and transportation.Small natural gas liquefaction plant play an important role for processing natural gas from remote areas and natural gas peak-shaving. This paper analysis the principle, the advantages and disadvantages in practical application of the gas liquefaction process. According to the characteristics and the of the application of small gas liquefaction plant, selected two small natural gas liquefaction process used in the plant-the single-stage mixed refrigerant liquefaction process and N2-CH4 expansion liquefaction process to simulation analysis.In this paper, the liquefaction processes were simulated by HYSYS, and evaluation and selection of physical property calculation methods for natural gas and mixed refrigerant, the PR state equation is finally used to calculate the properties of the natural gas and mixed refrigerant. After the establishment of a compressor, a condenser, LNG heat exchanger, throttle, thermodynamic model of gas-liquid separator and other equipment, the two small-scale liquefaction process HYSYS models were established simulated, and then acquire steady-state simulation data. Influences of gas temperature, pressure and flow rate, the refrigerant high pressure as well as the refrigerant low pressure on the power consumption were analyzed.Based on steady-state model, establish a dynamic model of a the single-state mixed refrigerant liquefaction process, simply examine dynamic response curve of the temperature and pressure of natural gas on the system power, natural gas molar flow rate, temperature of the gas outlet and the refrigerant molar flow.With the vigorous development of China's natural gas industry, the study of LNG technology will be more in-depth. In this paper, dynamic simulation liquefaction process is only preliminary studied and did not refer to other parameter changes the dynamic disturbance, which will also be the focus of future research.