| Methane is one kind of fossil gas resources of high utilization value and widely exists innatural gas and biogas. Due to the limited research and manufacturing technology, the small andscattered methane source usually cannot be mined efficiently, causing severe environmentalpollution and enormous waste of resources. In this paper, by using HYSYS to verify its feasibility,a compact methane liquefaction plant is designed and researched to be available for civil use,which has high economic value and environmental protection significance. Taking finned tubeheat exchanger for example, mechanical optimization design is introduced and the annualinvestment cost is taken as the objective function. Finally, the Mini Methane gas liquefactionplant is produced and successfully achieves-166.6℃. The main work and results are as follows:(1)Based on the pre-cooling with mixed-refrigerant liquefaction process which belongs tomature natural gas liquefaction technology, a Mini methane gas liquefaction plant is designed, itcan be used for Methane gas liquefaction under civilian conditions.(2)Using HYSYS simulation to analyze the liquefaction process, the process parameters andstructure is optimized in order to reduce system power consumption. A large number ofsimulation experiments are designed by SPSS to analyze the impact from pressure ratiocombination, refrigerant ratio and system junction temperature setting on system powerconsumption.(3)Taking finned tube heat exchanger for example, TLBO is presented to optimize thestructural parameters of the heat exchanger, which takes the minimum annual investment cost asthe objective function. The relationship between geometry construction and annual investmentcost is analyzed for manufacturing. Comparing with PSO and GA which are both matureoptimization algorithm, TLBO is better in usability and rate of convergence.(4)Finally Mini Methane liquefaction plant is produced. This device only has a smallvolume of3m3, which can achieves the lowest temperature at-166.6℃, Methane gas can beliquefied under atmospheric pressure.Compared with simulation data, operating date is consistent in the trend of the temperaturereduction. It proves that HYSYS simulation used in the design and optimization of liquefactionprocess is valid and important. |
