Effect of Pressure on the Behavior of Copper-, Iron-, and Nickel-Based Oxygen Carriers for Chemical-Looping Combustion

作者：Francisco Garcı́a-Labiano, Juan Adánez, Luis F. de Diego, Pilar Gayán, Alberto Abad · 发表于：Energy & Fuels · 年份：2005 · DOI：10.1021/ef050238e · 被引用次数：258 · 研究领域：Chemical Looping and Thermochemical Processes、Oil, Gas, and Environmental Issues、Carbon Dioxide Capture Technologies

The combustion process integrated by coal gasification and chemical-looping combustion (CLC) could be used in power plants with a low energy penalty for CO 2 capture. This work analyzes the main characteristics related to the CLC process necessary to use the syngas obtained in an integrated gasification combined cycle (IGCC) power plant. The kinetics of reduction with H 2 and CO and oxidation with O 2 of three high-reactivity oxygen carriers used in the CLC system have been determined in a thermogravimetric analyzer at atmospheric pressure. The iron- and nickel-based oxygen carriers were prepared by freeze-granulation, and the copper-based oxygen carrier was prepared by impregnation. The changing grain size model (CGSM) was used for the kinetic determination, assuming spherical grains for the freeze-granulated particles containing iron and nickel and a platelike geometry for the reacting surface of the copper-based impregnated particles. The dependence of the reaction rates on temperature was low, with the activation energy values varying from 14 to 33 kJ mol - 1 for the reduction and 7 to 15 kJ mol - 1 for the oxidation. The reaction order depended on the reacting gas and oxygen carrier, with values ranging from 0.25 to 1. However, an increase in the operating pressure for the IGCC + CLC system increases the thermal efficiency of the process, and the CO 2 is recovered as a high pressure gas, decreasing the energy demand for further compression. The effect of pressure on the ...