CO2 residual concentration of potassium-promoted hydrotalcite for deep CO/CO2 purification in H2-rich gas

作     者：Xuancan Zhu Yixiang Shi Ningsheng Cai 

作者机构：Key Laboratory for Thermal Science and Power Engineer of Ministry of EducationDepartment of Thermal EngineeringTsinghua UniversityBeijing 100084China 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2017年第26卷第5期

页      面：956-964页

核心收录：

学科分类：081702[工学-化学工艺] 081704[工学-应用化学] 07[理学] 070304[理学-物理化学(含∶化学物理)] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 

基　　金：financed by Shanxi Province Science and Technology Major Projects of MH2015-06 

主　　题：Potassium-promoted hydrotalcite Warm gas clean-up Elevated-temperature pressure swing adsorption CO deep purification High purity hydrogen production 

摘      要：Elevated-temperature pressure swing adsorption is a promising technique for producing high purity hydrogen and controlling greenhouse gas emissions. Thermodynamic analysis indicated that the CO in H-rich gas could be controlled to trace levels of below 10 ppm by in situ reduction of the COconcentration to less than 100 ppm via the aforementioned process. The COadsorption capacity of potassiumpromoted hydrotalcite at elevated temperatures under different adsorption（mole fraction, working pressure） and desorption（flow rate, desorption time, steam effects） conditions was systematically investigated using a fixed bed reactor. It was found that the COresidual concentration before the breakthrough of COmainly depended on the total amount of purge gas and the COmole fraction in the inlet *** residual COconcentration and uptake achieved for the inlet gas comprising CO（9.7 mL/min） and He（277.6 mL/min） at a working pressure of 3 MPa after 1 h of Ar purging at 300 mL/min were 12.3 ppm and0.341 mmol/g, respectively. Steam purge could greatly improve the cyclic adsorption working capacity, but had no obvious benefit for the recovery of the residual COconcentration compared to purging with an inert gas. The residual COconcentration obtained with the adsorbent could be reduced to 3.2 ppm after 12 h of temperature swing at 450 °C. A new concept based on an adsorption/desorption process, comprising adsorption, steam rinse, depressurization, steam purge, pressurization, and high-temperature steam purge, was proposed for reducing the steam consumption during CO/COpurification.