添加R141b促进剂的CO2水合物法海水淡化实验研究

我国天然气中CO₂的利用率非常低，净化过程中脱出的CO₂主要是排放，不仅会污染大气，也在无形中损失了巨额的经济效益，因而我国陆地和海上酸性气田开发中加强对CO₂的综合利用就显得尤为重要。CO₂水合物法海水淡化是一种新型的海水淡化技术，主要是利用较易生成水合物的小分子物质与海水生成水合物晶体，固液分离后，分解水合物即可得到淡水，该技术目前在我国尚处于室内实验研究阶段。为了提高CO₂水合物法海水淡化效率，在海水中添加R141b促进剂以加快CO₂水合物的生成速度，利用研制的双釜海水淡化实验装置，探讨了R141b促进剂的添加比例及其对CO₂水合物法海水淡化效率的影响，确定了该法的技术参数；通过测定水合物生成前后溶液的盐度及离子变化，探讨了CO₂水合物法海水淡化的程度。结果表明：①R141b促进剂与海水的最佳体积比为1∶70，添加R141b后CO₂水合物法海水淡化效率可提高3倍；②在一级和二级淡化水中，离子去除率平均分别可达58.7%和81.0%，而三级和四级淡化水的平均离子去除率则分别达到了94.8%和98.4%；③四级淡化水的各项离子浓度指标都优于饮用水标准。

An experimental study of CO2 hydrate-based seawater desalination with the R141b as an accelerant

In the previous development of those continental and offshore sour gas fields in China, CO₂ removed from the produced natural gas contributed a lot to carbon emission, which not only led to global warming but brought about a great loss. However, the recycling of CO₂ produced along with natural gas has aroused research interest in present China. CO₂ hydrate based desalination is a new seawater desalination technique that is still in laboratory research in China. This technique uses small molecule materials, which easily form hydrate, and seawater to form solid hydrate and after the solid liquid separation, fresh water can be obtained from the solid hydrate dissociation. In order to improve the efficiency of CO₂ hydrate based desalination, in this experimental study, R141b was used as an accelerant to accelerate the forming speed of CO₂ hydrate in seawater. Based on our experimental device with two reactors developed for hydrate seawater desalination, the R141b proportion and its effects on the efficiency of CO₂ hydrate based desalination were discussed, and the technical parameters of this method were also suggested. The degree of seawater desalination was discussed through measuring the variation of the salinities and ionic concentrations in the solution before and after the hydrate was formed. The following findings were achieved. a. The optimal v/v ratio of R141b to seawater was 1∶70. The efficiency of CO₂ hydrate based desalination with R141b was 3 times higher than that without R141b. b. The removing rates of ions in the first and second grade desalination water were 58.7% and 81.0%, respectively, and reached up to 94.8% and 98.4% in the third and fourth grade desalination water, respectively. c. The ionic concentrations in the fourth grade desalination water were even better than those in the national standard drinking water.