(118e) Regenerable MgO-Based Sorbents for CO2 Removal in IGCC Processes

Integrated Gasification-Combined Cycle (IGCC) processes are among the leading contenders for power generation conversion in the 21^st century because of their significantly higher efficiencies and potential environmental advantages compared to pulverized coal combustion (PC) processes.  The higher efficiency in IGCC processes reduces the emissions of CO₂ per unit of power generated by 30%.  Furthermore, the higher concentration of CO₂ and high pressure prevailing in the pre-combustion fuel gas, leads to additional advantages IGCC, if carbon capture and sequestration technology in implemented in  power generation processes.  In IGCC processes equipped with high temperature particulate removal and hot/warm temperature sulfur removal subsystems, to avoid efficiency losses, it is desirable to remove CO₂ in the temperature range of 300° to 500°C, which makes regenerable MgO-based sorbents ideal for such operations. In this temperature range, CO₂ removal results in shifting of water-gas-shift (WGS) reaction toward significant reduction in carbon monoxide (CO) concentration, generating additional hydrogen in the process, which is considered as a higher value product. However, highly durable, reactive, and attrition resistant sorbents are required for such application.

This paper presents the results obtained with a highly reactive and attrition resistant regenerable MgO-based sorbent which can simultaneously remove carbon dioxide and enhance hydrogen production in a single reactor. A brief overview on sorbent preparation technique will be presented and the effects of various variables such as calcination temperature, calcination time, impregnation method, and drying methods on the physical properties of the sorbents are discussed.  The effects of physical and chemical properties of the sorbents on their CO₂ reactivity and absorption capacity are also presented and discussed.