重整气中CO深度去除方法

提出了两段CO深度去除法(M-O法):第1段采用选择性甲烷化和第2段采用选择性氧化,即对水汽变换(WGS)反应器出口约含体积分数为1%CO的重整气进行选择性甲烷化,将CO去除至0.1%以下,而后进行选择性氧化将CO去除至10×10-6以下.实验结果表明:一方面,与两段选择性甲烷化CO深度去除法(M-M法)相比,M-O法具有相近的热效率,工作温度移向低温,可在更宽的温度区间和更高的空速下满足CO去除深度的要求;另一方面,M-M法系统简单,而M-O法具有反应器更加紧凑的优势.此外,还探讨了在上述两种工艺过程的后段再附加上一段高空速选择性氧化过程,可将CO的去除深度进而提高到1×10-6以下,更加有利于质子交换膜燃料电池电站系统长时间连续运行的稳定性.

Deep removal of CO in reformate

CO deep removal was investigated by combining preferential methanation and preferential oxidation (M-O method). In the M-O method, CO of about 1% in reformate from a water gas shift (WGS) reactor is reduced to about 0.1% in the first stage of preferential methanation, then further reduced to below 10×10~(-6)in the second stage of preferential oxidation. The results show that in comparison of the M-M method (a method of CO deep removal with two-stage preferential methanation) the M-O method could be operated with a wider temperature range and a higher gas hourly space velocity at a lower temperature, and has almost the same thermal efficiency. In the other hand, although a reaction system of the M-M method is simpler, a reaction reactor of the M-O method could be more compact in comparison. In addition, a high-speed preferential oxidation step set at the outlet of the second stage in the M-M method or M-O method was proposed to remove CO to below 1×10~(-6), which helps to enhance the stability of proton exchange membrane fuel cells under long time continuous running.