Abstract

There is an increasing interest in catalytic combustors fuelled by low-heating value (LHV) gases, with a LHV of 5–7 MJ/Nm3. This is because catalytic combustion could be advantageous compared to flame combustion with respect to stable combustion of LHV-gases and low conversions of fuel-N (mainly NH3) to NOX. In the present project, funded by the EU Joule Program, catalytic combustion of gasified wood for gas turbine applications is studied. A synthetic gas mixture of H2, CO, CO2,H2O,CH4,N2, and NH3, that resembles the output from a fluidized bed gasifier using biomass as raw material, is used. The gas mixture is mixed with air at atmospheric pressure and combusted over washcoated cordierite monoliths in a bench-scale laboratory quartz-reactor. The objectives of the work described here are twofold. To begin with, improvement of the thermal stability of hexaaluminate washcoats by substitutions of rare earth or transition metal compounds is being studied. Secondly, catalytic combustion of gasified biomass over these washcoats has been studied in a bench-scale unit. In this on-going project, obtained result show that it is possible to improve the surface area of hexaaluminate compounds up to 17 m2/g after careful synthesis and calcination up to 1400°C for four hours. The selectivity of NH3-conversion to N2 is at present at 60 percent, but varies strongly with temperature. Fuel components such as H2, CO, C2H4, and NH3 ignite at temperatures close to compressor outlet temperatures. This means that a pilot-flame may not be needed for ignition of the fuel. A comparison between a Pd-impregnated lanthanum hexaaluminate and a Mn-substituted lanthanum hexaaluminate showed that the ignition temperature and the NOX-formation varied strongly over the two different catalysts.

1.
Zwinkels
,
M. F. M.
,
Ja¨ra˚s
,
S. G.
,
Menon
,
P. G.
, and
Griffin
,
T. A.
,
1993
, “
Catalytic Materials for High-Temperature Combustion
,”
Catal. Rev. Sci. Eng.
,
35
, pp.
319
358
.
2.
Dalla Betta, R. A., Scalatter, J. C., Nickolas, S. G., Razdan, M. K., and Smith, D. A., 1995, “Application of Catalytic Combustion Technology to Industrial Gas Turbines for Ultra-Low NOX Emissions,” ASME Paper 95-GT-65.
3.
Sadamori, H., Nishida, T., Yamashita, T., Furuya, A., and Matsuhisa, T., 1995, “The Development of a High-Temperature Catalytic Combustion System,” Proceedings, Yokohama Int. Gas Turbine Cong., pp. 247–250.
4.
Ozawa, Y., Fujii, T., Sato, M., Kanazawa, T., and Inou, H., 1996, “Development of a Catalytically Assisted Combustor for a Gas Turbine,” Book of Abstracts, 3rd Int. Workshop on Catalytic Combustion, Amsterdam.
5.
Tucci, E. R., 1982, “Use Catalytic Combustion for LHV Gases,” Hydrocarbon Process., May, pp. 159–166.
6.
Sung
,
C. J. M.
,
Kennedy
,
L. A.
, and
Ruckenstein
,
E.
,
1984
, “
The Effect of Nitrogen Content on the Oxidation of Fuel Bound Nitrogen in a Transition Metal Oxide Catalytic Combustor
,”
Combust. Sci. Technol.
,
41
, pp.
315
325
.
7.
Johansson, E. M., and Ja¨ra˚s, S. G., 1996, “Circumventing Fuel-NOX in Catalytic Combustion of Gasified Biomass,” Book of Abstracts, 3rd Int. Workshop on Catalytic Combustion, Amsterdam.
8.
Johansson, E. M., and Ja¨ra˚s, S. G., 1996, “Circumventing Fuel-NOX in Catalytic Combustion of Gasified Biomass,” submitted to Catal. Today.
9.
Bridgwater
,
A. V.
,
1995
, “
The Technical and Economic Feasibility of Biomass Gasification for Power Generation
,”
Fuel
,
74
, pp.
631
653
.
10.
Machida
,
M.
,
Eguchi
,
K.
, and
Arai
,
H.
,
1989
, “
Catalytic Properties of BaMAl11O19-alfa (⁠M=Cr, Mn, Fe, Co, and Ni) for High-Temperature Catalytic Combustion
,”
J. Catal.
,
120
, pp.
377
386
.
11.
Lowe, D. M., Gusman, M. I., and McCarty, J. G., 1994, “Synthesis and Characterization of Sintering Resistant Aerogel Complex Oxide Powders,” in Preparation of Catalysts VI, G. Poncelet, et al., eds., Elsevier Science, Amsterdam, pp. 445–452.
12.
Groppi
,
G.
,
Belloli
,
A.
,
Tronconi
,
E.
, and
Forzatti
,
P.
,
1996
, “
Catalytic Combustion of CO-H2 on Manganese-Substituted Hexaaluminates
,”
Catal. Today
,
29
, pp.
403
407
.
13.
Johansson, E. M., and Ja¨ra˚s, S. G., 1997, “Catalytic Combustion of Low-Heating Value Fuel-Gases: Ignition of CO, H2, and CH4,” ACS Symp., Div. Petrol Chem., San Francisco, 42, pp. 146–150.
14.
Le Gal, J.-H., Martin, G., and Durand, D., 1998, “Development of a Dual Fuel Catalytic Combustor for a 2.3 MWe Gas Turbine,” submitted to ASME Turbo Expo Land, Sea and Air 98.
15.
Ersson, A. G., Johansson, E. M., and Ja¨ra˚s, S. G., 1998, “Techniques for Preparation of Manganese-Substituted Lanthanum Hexaaluminates,” in Studies in Surface Science and Catalysis, Preparation of Catalysts VII, G. Poncelet, eds., Elsevier Science, Amsterdam.
16.
Eguchi, K., Takahara, H., Inoue, H., Sekizawa, K., and Arai, H., 1997, “Catalytic Properties of Transition Metal Substituted Hexaaluminate for High Temperature Combustion,” ACS Symp., Div. Petrol Chem., San Francisco, 1997 42, pp. 180–182.
17.
Miller
,
J. A.
, and
Bowman
,
C. T.
,
1989
, “
Mechanism and Modeling of Nitrogen Chemistry in Combustion
,”
Prog. Energy Combust. Sci.
,
15
, pp.
287
338
.
18.
McCarty
,
J. G.
,
1995
, “
Kinetics of PdO Combustion Catalysis
,”
Catal. Today
,
26
, pp.
283
293
.
You do not currently have access to this content.