带压液化天然气流程中二氧化碳晶体析出现象初探  

Preliminary research on CO_2 freeze-out in PLNG process

作　　者：胡晓晨[1] 高婷[1] 林文胜[1] 

机构地区：[1]上海交通大学制冷与低温工程研究所,上海200240

出　　处：《低温与超导》2009年第6期15-18,共4页Cryogenics and Superconductivity

基　　金：上海交通大学"PRP"项目(T02014005)资助

摘　　要：带压液化天然气(PLNG)是在较高压力下(1~2MPa)液化并储存的天然气,对应的液化温度约-100^-120℃。较高的液化温度大大增加了LNG中CO2的溶解度,使得天然气液化流程有可能去掉占地很大的CO2预处理装置。不同条件下带压液化天然气中CO2晶体析出现象的研究是PLNG技术的基础。借助HYSYS软件,初步分析了天然气组分及PLNG储存温度对CO2晶体析出温度和溶解度的影响。结果表明,CO2和乙烷的含量对CO2析出温度有较大的影响,析出温度随着CO2浓度的增大而增大,而随乙烷含量的增大而降低;而氮含量对析出温度的影响较小。此外,随着PLNG储存温度的降低,二氧化碳溶解度也逐渐降低。Pressurized liquefied natural gas （PLNG） is liquefied and stored at a relatively high pressure of 1 - 2MPa, correspending to a temperature of - 100 - - 120 ℃. Because of higher temperature than that for conventional LNG, PLNG has a greater solubility for impurities such as COa. The pre - treatment of CO2will therefore be simpler and can even be canceled. The research on the freeze -out problem of CO2at different conditions is crucial to PLNG technology. In this paper, the changes of the composition of natural gas and the PLNG storage temperature are considered as factors that influence the CO2 freeze -out temperature and solubility in the liquefied gas, and simulation is done with the software HYSYS. The results show that the concentrations of CO2 and ethane have great effect on the freeze - out temperature. A decrease in CO2 fraction will lead to a decrease in freeze - out temperature, while an increase in ethane fraction will also make a decrease in CO2 freeze - out temperature. The amount of nitrogen shows slight influence on the freeze - out temperature. Furthermore, with the decrease of the storage temperature, the solubility of CO2 will decrease gradually.

关 键 词：带压液化天然气 二氧化碳 晶体析出 溶解度 

分 类 号：TQ231.22[化学工程—有机化工] TE646[石油与天然气工程—油气加工工程]