Fullwood, M
1994
Catalysis of Char Oxidation by Calcium Minerals: Effects of Calcium Compound Chemistry on Intrinsic Reactivity of Doped Spherocarb and Zap Chars
Gopalakrishnan, R.; Fullwood, M. and Bartholomew, C.H.
Energy & Fuels, 8:984-989, 1994. Funded by ACERC.
Catalysis by CaO, CaCo3, and CaSO4 of the oxidation of a well-defined, high purity synthetic char, Spherocarb, was investigated at low reaction temperatures using thermogravimetric analysis. The results indicate significant catalytic effects-up to 160-fold increase for CaCO3 catalysis, 290-fold increase for CaSO4, and up to 2700 times for CaO. Oxidation rates were likewise measured for fresh, demineralized, and Ca-loaded chars prepared from Beulah-Zap lignite coal in a flat flame burner at 1473 K. The oxidation rates of CaO-catalyzed Spherocarb and Zap are the same within experimental error, suggesting that the high reactivity of the Zap char is due in large part to catalysis by CaO. It was also found that chlorine added to Ca-loaded char had a negligible effect on its low-temperature reactivity.
1993
Effects of CaO, CaSO4 and Coal Rank on Low- and High-Temperature Char Oxidation Rates
Gopalakrishnan, R.; Fullwood, M.; Moody, S.; Cope, R.F. and Bartholomew, C.H.
Proceedings of the 7th International Conference on Coal Science, Banff, Canada, September 1993. Funded by ACERC.
This study is part of an ongoing program to investigate (a) rates and mechanisms of Ca-catalyzed oxidation of synthetic char and chars prepared from representative U.S. coals and (b) the chemical nature of active catalytic sites for oxidation on those inorganic mineral phases present in coal chars.
1991
Catalysis of Char Gasification in O2 by CaO and CaCO3
Bartholomew, C.H.; Gopalakrishnan, R. and Fullwood, M.
ACS Fuel Division, 36(3):982-989, 1991 (4th Chemical Congress of North America, New York, NY, August 1991). Funded by ACERC.
Catalysis by CaO and CaCO3 of the oxidation of a well-defined, high purity synthetic char, Spherocarb, was investigated at low reaction temperatures using thermal gravimetric analysis (TGA). Oxidation rates were likewise measured for fresh, demineralized, and Ca-impregnated samples of a high temperature char prepared in a flat-flame burner at about 1300 K from Beulah Zap coal. Spherocarb and demineralized Zap char were impregnated with Ca using aqueous impregnation and ion-exchange techniques. The resulting kinetic parameters for Spherocarb indicate significant catalytic effects--up to a 100 fold increase in reaction rate for CaCO3 and 3,000 in the case of CaO. The oxidation rates of CaO-catalyzed Spherocarb and Beulah Zap char are the same within experimental error, suggesting that the high reactivity of the Zap char is due in large part to catalysis by CaO.
Calcium Oxide Catalysis of Char Oxidation
Bartholomew, C.H.; Gopalakrishnan, R. and Fullwood, M.
8th Annual International Pittsburgh Coal Conference, 1140, Pittsburgh, PA, October 1991. Funded by ACERC.
Catalysis by CaO and CaCO3 of the oxidation of a well-defined, high purity synthetic char, Spherocarb, was investigated at low reaction temperatures using thermal gravimetric analysis (TGA). Oxidation rates were likewise measured for fresh, demineralized, and Ca-impregnated samples of a high temperature char prepared in a flat-flame burner at about 1300 K from Beulah Zap coal. Spherocarb and demineralized Zap char were impregnated with Ca using aqueous impregnation and ion-exchange techniques. The resulting kinetic parameters for Spherocarb indicate significant catalytic effects--up to a 100 fold increase in reaction rate for CaCO3 and 3,000 in the case of CaO. The oxidation rates of CaO-catalyzed Spherocarb and Beulah Zap char are the same within experimental error, suggesting that the high reactivity of the Zap char is due in large part to catalysis by CaO.
1990
Calcium Oxide Catalysis of Char Oxidation
Bartholomew, C.H.; Gopalakrishnan, R. and Fullwood, M.
Proc. ASME Seminar on Fouling of Western Coals, Brigham Young University, Provo, UT, 1990. (Also presented at the National AlChE Meeting, Chicago, 1990). Funded by ACERC.
Catalysis by CaO of the oxidation of a well-defined, high purity synthetic char, Spherocarb, was investigated at low reaction temperatures using thermal gravimetric analysis (TGA). Spherocarb was impregnated with Ca using aqueous impregnation and ion-exchange techniques. The resulting kinetic parameters indicate a significant catalytic effect--10 to 100-fold increases in reaction rate. CO adsorption on CaO prepared by Ca(OH)2 decomposition was investigated using temperature-programmed desorption (TPD) of CO adsorbed at 298 K. Several high temperature peaks were observed consistent with heats of adsorption of 40-115 kJ/mal. These relatively large heats of adsorption are indicative of the presence of different, strongly adsorbed CO species on CaO and have significant implications for the catalysis of carbon oxidation and of CO oxidation to CO2 during char combustion. Experiments involving temperature-programmed reaction of hydrogen with adsorbed CO also indicate by the formation of methane that CO may adsorb dissociatively or at least dissociates in the presence of hydrogen to form methane.
Fullwood, M
1994
Catalysis of Char Oxidation by Calcium Minerals: Effects of Calcium Compound Chemistry on Intrinsic Reactivity of Doped Spherocarb and Zap Chars
Gopalakrishnan, R.; Fullwood, M. and Bartholomew, C.H.
Energy & Fuels, 8:984-989, 1994. Funded by ACERC.
Catalysis by CaO, CaCo3, and CaSO4 of the oxidation of a well-defined, high purity synthetic char, Spherocarb, was investigated at low reaction temperatures using thermogravimetric analysis. The results indicate significant catalytic effects-up to 160-fold increase for CaCO3 catalysis, 290-fold increase for CaSO4, and up to 2700 times for CaO. Oxidation rates were likewise measured for fresh, demineralized, and Ca-loaded chars prepared from Beulah-Zap lignite coal in a flat flame burner at 1473 K. The oxidation rates of CaO-catalyzed Spherocarb and Zap are the same within experimental error, suggesting that the high reactivity of the Zap char is due in large part to catalysis by CaO. It was also found that chlorine added to Ca-loaded char had a negligible effect on its low-temperature reactivity.
1993
Effects of CaO, CaSO4 and Coal Rank on Low- and High-Temperature Char Oxidation Rates
Gopalakrishnan, R.; Fullwood, M.; Moody, S.; Cope, R.F. and Bartholomew, C.H.
Proceedings of the 7th International Conference on Coal Science, Banff, Canada, September 1993. Funded by ACERC.
This study is part of an ongoing program to investigate (a) rates and mechanisms of Ca-catalyzed oxidation of synthetic char and chars prepared from representative U.S. coals and (b) the chemical nature of active catalytic sites for oxidation on those inorganic mineral phases present in coal chars.
1991
Catalysis of Char Gasification in O2 by CaO and CaCO3
Bartholomew, C.H.; Gopalakrishnan, R. and Fullwood, M.
ACS Fuel Division, 36(3):982-989, 1991 (4th Chemical Congress of North America, New York, NY, August 1991). Funded by ACERC.
Catalysis by CaO and CaCO3 of the oxidation of a well-defined, high purity synthetic char, Spherocarb, was investigated at low reaction temperatures using thermal gravimetric analysis (TGA). Oxidation rates were likewise measured for fresh, demineralized, and Ca-impregnated samples of a high temperature char prepared in a flat-flame burner at about 1300 K from Beulah Zap coal. Spherocarb and demineralized Zap char were impregnated with Ca using aqueous impregnation and ion-exchange techniques. The resulting kinetic parameters for Spherocarb indicate significant catalytic effects--up to a 100 fold increase in reaction rate for CaCO3 and 3,000 in the case of CaO. The oxidation rates of CaO-catalyzed Spherocarb and Beulah Zap char are the same within experimental error, suggesting that the high reactivity of the Zap char is due in large part to catalysis by CaO.
Calcium Oxide Catalysis of Char Oxidation
Bartholomew, C.H.; Gopalakrishnan, R. and Fullwood, M.
8th Annual International Pittsburgh Coal Conference, 1140, Pittsburgh, PA, October 1991. Funded by ACERC.
Catalysis by CaO and CaCO3 of the oxidation of a well-defined, high purity synthetic char, Spherocarb, was investigated at low reaction temperatures using thermal gravimetric analysis (TGA). Oxidation rates were likewise measured for fresh, demineralized, and Ca-impregnated samples of a high temperature char prepared in a flat-flame burner at about 1300 K from Beulah Zap coal. Spherocarb and demineralized Zap char were impregnated with Ca using aqueous impregnation and ion-exchange techniques. The resulting kinetic parameters for Spherocarb indicate significant catalytic effects--up to a 100 fold increase in reaction rate for CaCO3 and 3,000 in the case of CaO. The oxidation rates of CaO-catalyzed Spherocarb and Beulah Zap char are the same within experimental error, suggesting that the high reactivity of the Zap char is due in large part to catalysis by CaO.
1990
Calcium Oxide Catalysis of Char Oxidation
Bartholomew, C.H.; Gopalakrishnan, R. and Fullwood, M.
Proc. ASME Seminar on Fouling of Western Coals, Brigham Young University, Provo, UT, 1990. (Also presented at the National AlChE Meeting, Chicago, 1990). Funded by ACERC.
Catalysis by CaO of the oxidation of a well-defined, high purity synthetic char, Spherocarb, was investigated at low reaction temperatures using thermal gravimetric analysis (TGA). Spherocarb was impregnated with Ca using aqueous impregnation and ion-exchange techniques. The resulting kinetic parameters indicate a significant catalytic effect--10 to 100-fold increases in reaction rate. CO adsorption on CaO prepared by Ca(OH)2 decomposition was investigated using temperature-programmed desorption (TPD) of CO adsorbed at 298 K. Several high temperature peaks were observed consistent with heats of adsorption of 40-115 kJ/mal. These relatively large heats of adsorption are indicative of the presence of different, strongly adsorbed CO species on CaO and have significant implications for the catalysis of carbon oxidation and of CO oxidation to CO2 during char combustion. Experiments involving temperature-programmed reaction of hydrogen with adsorbed CO also indicate by the formation of methane that CO may adsorb dissociatively or at least dissociates in the presence of hydrogen to form methane.