CO2水合反应循环增压实验研究

Experimental study on circulation pressurization of carbon dioxide hydration reaction

关键词:  CO₂  循环增压系统  水合物  套管式反应器 

Key words:  carbon dioxide  circulation pressurization system  hydrate  double-tube reactor

摘要:

针对CO₂作为天然工质优越的制冷特性以及水合物技术在多领域的发展前景,利用水合物相平衡转折温度下压力急剧上升的特点,通过流程的创新设计,提出了一种利用CO₂水合物交替生成与分解的过程来实现增压的循环系统。基于CO₂复叠制冷低温级的热力学分析,结合对相平衡转折温度的考虑,通过实验表明,在套管式反应器中,0.3%(质量分数)SDS的动力学添加剂较之4%(质量分数)THF热力学添加剂更能促进CO₂水合物的生成, 在-2 ℃、1.4 MPa的前提下,合成时间为60 min；在0.3%SDS的溶液中,温度越低越易于水合物生成,其临界温度接近于-2 ℃,低于-2 ℃时,溶液结冰会堵塞管道；两套管式反应器交替运行,得到了-2 ℃合成、10 ℃分解的最佳循环温度,55 min的最短循环时间,分解后的高压CO₂气体经冷凝节流后达到了-36 ℃的低温。 

Abstract:

Based on the excellent cooling characteristics of CO₂ as a natural working substance and development prospects in the field of many hydrate technology, using the characteristics of pressure rising sharply under the phase equilibrium transition temperature of hydrate, through the innovation design of process, the carbon dioxide hydrate formation and decomposition alternate process is used to realize the pressurization system. Based on thermodynamic analysis of carbon dioxide level cascade refrigeration and combining with the phase equilibrium temperature, the experiment results show that the dynamics of 0.3wt% SDS additives is more advantageous to promote the formation of carbon dioxide hydrate in double-tube reactor compare with 4wt% THF thermodynamics additive. The synthesis time is 60 minutes at 1.4 MPa and -2 ℃. In SDS solution of 0.3wt%, lower temperature is more beneficial to the formation of hydrate, the critical temperature is close to -2 ℃. When it is lower than -2 ℃, the solution icing may block pipe. When the two sets of tube reactors are used alternately, the optimum cyclic temperature is as follows:the synthesis temperature is -2 ℃, the decomposition temperature is 10 ℃, and the shortest cycle time is 55 minutes. The carbon dioxide gas under high pressure is decomposed by condensation throttle to a low temperature of -36 ℃.