Nickel-Copper Oxygen Carriers To Reach Zero CO and H2 Emissions in Chemical-Looping Combustion
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- 作者：Juan Adá ; nez ; Francisco Garcí ; a-Labiano ; Luis F. de Diego ; Pilar Gayá ; n ; Javier Celaya ; and Alberto Abad
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2006
- 出版时间：April 12, 2006
- 年：2006
- 卷：45
- 期：8
- 页码：2617 - 2625
- 全文大小：177K
- 年卷期：v.45,no.8(April 12, 2006)
- ISSN：1520-5045
文摘
Ni-based oxygen carriers allow working at high temperatures (900-1100 
C) in a chemical-looping combustion(CLC) process with full CH4 conversion, although thermodynamic restrictions result in the presence of COand H2 in the gas outlet of the fuel reactor. On the other hand, Cu-based oxygen carriers allow complete fuelcombustion to CO2 and H2O, but the operating temperature is limited due to the low melting point of themetallic Cu. The objective of this research was to analyze the behavior of several Ni-Cu oxygen carriers toreduce or avoid CO and H2 emissions during a CLC process working at high temperatures. Commercial
-Al2O3 and 
-Al2O3 were used as support to prepare by dry impregnation different oxygen carriers based onnickel and copper. The reactivity of these oxygen carriers was determined in a thermogravimetric analyzer(TGA). The effect of the mixture of NiO and CuO on the CO and H2 generation was analyzed in a fixed bedreactor, and the gas product distribution during reduction/oxidation reactions was studied in a batch fluidizedbed reactor working with CH4 as fuel and diluted air for oxidation. The fluidization behavior of the oxygencarriers with respect to the attrition and agglomeration processes was also analyzed during the multicyclebatch fluidized bed tests. The presence of CuO in the Ni-Cu oxygen carriers allows the full conversion ofCH4 to CO2 and H2O in the batch fluidized bed reactor during the initial part of the reduction time, and thistime depended on the CuO content of the oxygen carrier. TGA and X-ray diffraction studies indicated thatCuO is used for the reduction reaction before NiO. In addition, it was observed that the presence of NiOstabilized the CuO and allowed working at 950 C with Ni-Cu oxygen carriers with a high metal oxideutilization.
C) in a chemical-looping combustion(CLC) process with full CH4 conversion, although thermodynamic restrictions result in the presence of COand H2 in the gas outlet of the fuel reactor. On the other hand, Cu-based oxygen carriers allow complete fuelcombustion to CO2 and H2O, but the operating temperature is limited due to the low melting point of themetallic Cu. The objective of this research was to analyze the behavior of several Ni-Cu oxygen carriers toreduce or avoid CO and H2 emissions during a CLC process working at high temperatures. Commercial-Al2O3 and -Al2O3 were used as support to prepare by dry impregnation different oxygen carriers based onnickel and copper. The reactivity of these oxygen carriers was determined in a thermogravimetric analyzer(TGA). The effect of the mixture of NiO and CuO on the CO and H2 generation was analyzed in a fixed bedreactor, and the gas product distribution during reduction/oxidation reactions was studied in a batch fluidizedbed reactor working with CH4 as fuel and diluted air for oxidation. The fluidization behavior of the oxygencarriers with respect to the attrition and agglomeration processes was also analyzed during the multicyclebatch fluidized bed tests. The presence of CuO in the Ni-Cu oxygen carriers allows the full conversion ofCH4 to CO2 and H2O in the batch fluidized bed reactor during the initial part of the reduction time, and thistime depended on the CuO content of the oxygen carrier. TGA and X-ray diffraction studies indicated thatCuO is used for the reduction reaction before NiO. In addition, it was observed that the presence of NiOstabilized the CuO and allowed working at 950 C with Ni-Cu oxygen carriers with a high metal oxideutilization.