【作者】 赵国伟；

【导师】 贾林祥；

【作者基本信息】 哈尔滨工业大学 ， 制冷及低温工程， 2009， 硕士

【摘要】 液化天然气行业作为一门新兴的产业正在日益发展壮大,我国的天然气液化技术也在迅猛发展。与国外的天然气液化技术相比,我国的天然气液化技术起步较晚,差距较大。尤其是在天然气液化流程的模拟方面,研究的比较少。考虑到当前国内外天然气液化的研究现状和行业实际需求,我国需要对液化天然气技术开展进一步的研究和探讨。本文对单级混合制冷剂天然气液化流程进行了动态模拟和研究。本文首先论述了国内外天然气液化技术的现状和发展趋势,分别阐述了几种天然气液化流程的特点,介绍了国内外天然气液化流程的稳态模拟及动态模拟的发展历程,并说明了流程模拟在液化天然气工程中的意义。本文介绍了天然气和混合制冷剂热物性的特点,分析了物性的计算方法和思路,比较了用状态方程法和活度系数法计算天然气和混合制冷剂物性的异同,确定使用Peng-Rob(PR)方程进行天然气和混合制冷剂物性的计算,并详细阐述了PR方程的形式,混合法则及求解过程。本文采用Aspen Plus软件对单级混合制冷剂天然气液化流程进行稳态模拟,建立了天然气液化流程的模型,并对流程中的压缩机、节流阀、气液分离器、冷却器、多股流换热器等模块进行详细的参数设置,最终得到了稳态模拟的结果。在稳态模拟的基础上,用Aspen Dynamics软件对单级混合制冷剂天然气液化流程进行动态模拟,建立了流程的动态模型,模拟并分析了天然气进换热器温度、压力、甲烷的摩尔含量以及混合制冷剂进压缩机温度、压力、混合制冷剂中的甲烷、乙烯、丙烷、异戊烷、氮气摩尔含量等参数的扰动对整个液化流程性能的影响。更多还原

【Abstract】 The liquefied natural gas (LNG) industry is developing day by day as a new industry, and liquefied natural gas technology of our nation is also developing rapidly. Compared with foreign liquefied natural gas technology, liquefied natural gas technology of our nation starts a little later and fall behind foreign countries. Especially in the simulation of natural gas liquefaction process, the research of our nation is a bit less. In view of research status of liquefied natural gas home and abroad and the actual demand of the industry, it is necessary for us to study and research the liquefied natural gas technology. This thesis simulates and studies the single stage mixed-refrigerant natural gas liquefaction process dynamically.The article expounds the status and development tendency of the liquefied natural gas technology home and abroad, describes the characteristics of several natural gas liquefaction processes respectively, analyzes calculating methods of property and introduces the development history of the steady simulation and dynamical simulation of the natural gas liquefaction process, and explicates the significance of process simulation in the liquefied natural gas engineering.The article describes the characteristics of the properties of natural gas and mixed refrigerant, introduces the calculating methods, and compares the similarities and differences of using the state equation method and the activity coefficient method respectively to calculate the properties of the natural gas and mixed refrigerant. The PR state equation is finally used to calculate the properties of the natural gas and mixed refrigerant, and its form, mixing rule and solving process are described in detail.The article carries on a steady simulation of the single stage mixed- refrigerant natural gas liquefaction process by Aspen Plus, establishes corresponding thermodynamic models of major apparatuses in the liquefaction process such as compressor, valve, flash tank, heat exchanger. The process model is created and specifications of every module are inputted, and the steady result is acquired.The dynamical simulation of the single stage mixed-refrigerant natural gas liquefaction process is carried on by Aspen dynamics based on the steady simulation. The dynamical model is established and the disturbing effects of the inlet temperature, pressure of the natural gas and the methane’s mole fraction in it, the inlet temperature, pressure of the mixed refrigerant and the mole fraction of methane, ethylene, propane, iso-pentane and nitrogen in it on the whole liquefaction process are simulated and analyzed.更多还原