| Natural gas with its efficient and clean properties has become one of the mainenergy in21stcentury, and its consumption has the growing trend. The small scaleliquefied natural gas (LNG) project has its strategic value in our country due to itscompact size, skid-mounted, and convenience in start-up and shut-down, which canbe used in small yield disperse gas fields. This paper studies the project and its keytechnologies, and the main research contents are as follows:Firstly, by researching the small natural gas liquefaction process and device bothat home and abroad, choose the air expansion type natural gas liquefaction process asthe research object of this article.Secondly, by thermodynamic exergy analyzing the small scale natural gasliquefaction process, find the key link of the irreversible loss and improving potential,and by optimizing the regenerator in the process, the performance of the system wasimproved. Through further exergy analysis and pinch analysis, by improving thestructure of the liquefaction process, makes the improvement process of liquefactionrate of100%, and the specific power consumption is lower. In this paper, consideringpressure drop of the heat exchanger, optimize the system performance, the optimalresults are obtained.Thirdly, based on natural gas liquefaction system optimization results, design thelow temperature heat exchanger. Through qualitative and quantitative comparativeanalysis, choose plate fin heat exchanger as low temperature heat exchanger device ofthe small natural gas liquefaction process. Application of heat exchanger designsoftware of Aspen MUSE to preliminary design, determine the basic structure of theheat exchanger. On this basis, the application of particle swarm optimizationalgorithm for MUSE software design of the heat exchanger core body, with the aim tooptimize the size and the quality was optimized, respectively to get the size and thequality of optimal heat exchanger core body. On the basis of the optimal heatexchanger structure parameters with best quality, the distribution structure of heatexchanger is designed. Eventually to the need of low temperature heat exchanger heatpreservation and heat insulation, carry on the overall design of cold box, in order tomeet the requirements of skid-mounted.Fourthly, in order to meet the requirements of skid-mounted, plate-fin heatexchanger is chosen as the compressor air cooler. By MUSE software carry on thedesign in different air flow rate, to make sure the best air flow rate of air cooler. Underthe optimum air flow conditions, the heat exchanger fin parameters and overalldimensions is fixed. And in accordance with the requirements of air flow rate andpressure drop, the fan model is determined. |
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