Adsorptive drying of CO₂ using low grade heat and humid, ambient air

详细信息    查看全文

• 作者：Brenden Tanchuk ; James A. Sawada ; Sabereh Rezaei ; Steven M. Kuznicki
• 关键词：Carbon dioxide ; Gas drying ; Adsorption ; ETS-10 ; Zeolites
• 刊名：Separation and Purification Technology
• 出版年：13 December, 2013
• 年：2013
• 卷：120
• 期：Complete
• 页码：354-361
• 全文大小：791 K

文摘

Adsorptive separation of water from CO₂ is an appealing alternative to liquid absorbers for post-combustion capture systems. In all cases, the purified CO₂ stream from a PCC system will have a high moisture content and, due to equipment corrosion issues and the risk of hydrate formation, the CO₂ stream must be rigorously dried prior to being compressed. This work reports the first study on solid adsorbent selection for CO₂ drying using low grade heat and ambient air as a regeneration gas. Different types of adsorbents, chosen for their range of water adsorption characteristics, have been investigated for the desiccation of a pure CO₂ stream. When destined for sequestration the CO₂ product gas has little value and so the drying process should require no supporting process operations and should consume little additional energy. However, due to the costs and complexity of separating and purifying CO₂ from a flue gas stream, the drying process should return as much CO₂ as possible to the compression stage. An ideal desiccant for CO₂ drying should have a high moisture capacity and selectivity and should be regenerable using waste heat and ambient, humid air. The CO₂ drying performance of Na-, Ca-, and Ca/H- forms of ETS-10 were compared to that of commercial silica and 4A zeolite. Ca-ETS-10 was found to have the highest moisture capacity using a temperature swing of 30-70 掳C and a CO₂ feed stream of 50-100% relative humidity. Due to the intrinsic selectivity for water over CO₂ on solid adsorbents, all desiccants tested had a CO₂ recovery greater than 95%.