Water recovery from stripping gas overhead CO2 desorber through air cooling enhanced by transport membrane condensation
Water recovery from stripping gas overhead CO2 desorber through air cooling enhanced by transport membrane condensation
复制标题
通过传输膜冷凝增强空气冷却，从汽提气塔顶 CO2 解吸器中回收水
DOI：
10.1016/j.seppur.2019.01.058
复制
发表时间：
2019-05-15
影响因子：
8.6
通讯作者：
Yan, Shuiping
中科院分区：
文献类型：
--
作者：
Tu, Te;Cui, Qiufang;Yan, Shuiping
在CO2化学吸收过程中的CO2再生阶段，对离开CO2解吸塔的汽提气体（即H2O(g)/CO2）进行冷却，使冷凝物返回解吸塔。大多数情况下，循环冷却水被用来提供这种冷却任务。在本研究中，以减少化学吸收过程的额外冷却水负荷为目的，研究了运输膜冷凝增强的空冷技术。采用管内分离层平均孔径为4 nm、膜长为400 mm的管状亲水陶瓷膜，以N-2为扫气从H2O(g)/CO2中回收水。结果表明，相同尺寸的n -2冷却陶瓷膜冷凝器的冷却性能是n -2冷却不锈钢冷凝器的4-7倍左右。采用n -2冷却陶瓷膜冷凝器从H2O(g)/CO2中回收水时，增大进水H2O(g)/CO2的流量和压力，可使换水通量增大。随着H2O(g)/CO2中H2O(g)摩尔分数的增加，换水通量也随之增加。此外，增加N-2流量和降低入口N-2压力可以提高换水性能。H2O(g)/CO2和N-2的温度对换水通量的影响较小。最后，提出了n -2冷却陶瓷膜冷凝器的换水通量随关键运行变量的经验相关关系。大部分计算的换水通量数据与实验结果吻合较好，平均绝对偏差为12.5%。
At the CO2 regeneration stage in a CO2 chemical absorption process, the stripping gas (i.e., H2O(g)/CO2) leaving the CO2 desorber is cooled down to return the condensate into the desorber. Mostly the circulating cooling-water is used to provide this cooling duty. In this study, the air-cooling technology enhanced by transport membrane condensation was investigated with the aim of reducing the additional cooling-water duty of the chemical absorption process. A tubular hydrophilic ceramic membrane with the mean pore size of the inner separation layer of 4 nm and the length of 400 mm was used for water recovery from H2O(g)/CO2 using N-2 as the sweeping gas. Results showed that the cooling performance of the N-2-cooling ceramic membrane condenser is about 4-7 times higher than that of the N-2-cooling stainless steel condenser with the same dimensions. For the water recovery from H2O(g)/CO2 using the N-2-cooling ceramic membrane condenser, increasing the flow rate and pressure of inlet H2O(g)/CO2 can bring about the increase of the water transfer flux. The water transfer flux can increase with the H2O(g) molar fraction in H2O(g)/CO2 as well. Additionally, the increase of N-2 flow rate in addition to the reduction of inlet N-2 pressure can enhance the water transfer performance. Moreover, the temperatures of H2O(g)/CO2 and N-2 have little impacts on the water transfer flux. Finally, an empirical correlation for predicting the water transfer flux as a function of the key operation variables was proposed for the N-2-cooling ceramic membrane condenser. Most of the calculated water transfer flux data are in good agreement with the experimental results with an average absolute deviation of 12.5%.