Chemical Looping Combustion in a 10 kWth Prototype Using a CuO/Al2O3 Oxygen Carrier: Effect of Operating Conditions on Methane Combustion

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• 作者：Juan Adá ; nez ; Pilar Gayá ; n ; Javier Celaya ; Luis F. de Diego ; Francisco Garc&iacute ; a-Labiano ; Alberto Abad
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2006
• 出版时间：August 16, 2006
• 年：2006
• 卷：45
• 期：17
• 页码：6075 - 6080
• 全文大小：142K
• 年卷期：v.45,no.17(August 16, 2006)
• ISSN：1520-5045

文摘

Chemical looping combustion (CLC) currently is an attractive option to decrease the greenhouse gas emissionsthat affect global warming, because it is a combustion process with inherent CO₂ separation and with lowenergy losses. The CLC concept is based on the transfer of oxygen from the combustion air to fuel by meansof an oxygen carrier in the form of a metal oxide. The system consists of two separate but interconnectedreactors, normally fluidized-bed type. In the fuel reactor, the oxygen carrier particles react with fuel andgenerate a gas stream mainly composed of CO₂ and H₂O. The reduced metal oxide is later transported to theair reactor, where oxygen from the air is transferred to the particles; in this way, one can obtain the originalmetal oxide ready to be returned to the fuel reactor for a new cycle. In this work, a 10 kW_th pilot plant thatis composed of two interconnected bubbling fluidized-bed reactors has been designed and built to demonstratethe CLC technology. The prototype was operated for 200 h, 120 h of which involved the burning of methane.The effect of the operating conditions (oxygen carrier-to-fuel ratio, fuel gas velocity, oxygen carrier particlesize, and fuel reactor temperature) on fuel conversion was analyzed working with a CuO-Al₂O₃ oxygencarrier prepared by dry impregnation. In addition, the behavior with respect to attrition, agglomeration, andreactivity of the oxygen carrier was analyzed. It was found that the most important parameter that was affectingthe CH₄ conversion was the oxygen carrier-to-fuel ratio. Complete methane conversion, without CO or H₂emissions, was obtained with this oxygen carrier working at 800 C and oxygen carrier-to-fuel ratios of>1.4.