基于可再生、生物型促进剂的绿色高效水合分离实验及机理研究

The major issues restricting the industrial application of the separation of gas mixtures by hydrate method are slow formation rate, low gas storage capacity and small separation factor (selectivity). Consequently, the separation efficiency is relatively low. Besides, most frequently-used hydrate thermodynamics and kinetics promotors in separation process have relatively high cost, and some of them have pungent flavor,corrosivity and toxicity, resulting in the pollution to the gas products and the environment. Therefore, renewable, low-cost and biological promotors for hydrates are proposed to be the alternative, and green and efficient separations of gas mixtures are able to be achieved via novel bio-hydrates formation. In this project, natural biosurfactants are expected to be developed from various kinds of plants and their derivatives, and the hydrate separation process containing forward and reverse order hydration reactions will be built by rational combination of bio-promotors, which could increase the hydrate formation rate and gas storage capacity, as well as the separation factor and the recovery of target components. The influence mechanism of the bio-promotors on the hydration rate and gas storage capacity will be investigated through the qualitative analysis of bio-hydrates molecular structure and composition by raman spectrometer. The development and application of the bio-promotors for hydrate could significantly decrease the cost and energy consumption of hydrate separation method, and increase the separation efficiency, which will effectively promote the spread and practical application of the technology.

制约水合物法分离混合气体技术工业应用的主要因素是水合物生成速率慢、储气能力以及分离因子（选择度）小，从而造成分离效率偏低，且分离过程中常用的水合物热力学及动力学促进剂成本较高，大部分具有一定的刺激性、腐蚀性或毒性，对产品气体及环境易造成污染。为此，提出用可再生、低成本的生物促进剂代替以往的水合物促进剂，以生成"生物型水合物"的新型方法实现混合气体的绿色、高效分离，研究从不同品系植物及其衍生物中开发纯天然的"生物型"表面活性剂，以及通过促进剂的合理搭配实现顺、逆序水合方法构建水合分离过程，实现提高水合物生成速率和储气能力，增加分离因子和目标组分回收率的目的。结合拉曼光谱仪定性分析生物型水合物的分子结构和组成，探讨生物型促进剂对水合反应速度和储气能力的影响机理。"生物型"水合物促进剂的开发利用将大大降低水合分离技术的成本和能耗，提高分离效率，有效促进该技术的发展推广及工业化应用。

目前，常用的水合物热力学及动力学促进剂，例如四氢呋喃、四丁基溴化铵等，大都具有一定的刺激性、腐蚀性或毒性，易对产品气体及环境易造成污染，严重制约水合物法分离混合气体技术的发展。为解决传统水合物促进剂的这一缺点，本课题提出开发可再生的“生物型”水合物促进剂，实现绿色的水合物分离技术。为此，首先采用“压力搜索法”分别考察了木质素磺酸钙、茶多酚、异辛基葡萄糖苷、正己基葡萄糖苷、辛癸基葡萄糖苷、精氨酸、脯氨酸和甜菜碱对甲烷水合物生成条件的热力学作用效果；其次采用“恒温恒压法”完成不同促进剂溶液中甲烷水合物的生成动力学测定；最后，选择适宜的“生物型”促进剂完成了水合物法分离煤层气实验。实验结果表明，异辛基葡萄糖苷对甲烷水合物具有一定的热力学促进作用，而脯氨酸和甜菜碱则表现为热力学抑制剂。木质素磺酸钙、茶多酚、辛癸基葡萄糖苷、正己基葡萄糖苷和异辛基葡萄糖苷体系的水合反应速率及水合物储气量明显高于纯水体系，是良好的水合物动力学促进剂。在辛癸基葡萄糖苷、正己基葡萄糖苷和异辛基葡萄糖苷三种不同溶液中均可利用水合物法实现煤层气的分离，尤以正己基葡萄糖苷体系可获得较高的甲烷回收率。“生物型”水合物促进剂的开发利用能够有效解决传统促进剂存在的毒性及刺激性等缺点，有利于促进水合分离技术的工业化应用。