Catalytic flameless combustion

Leanza, R Rossetti, 1 Fabbrini, L Oliva, C Fomi, L. Perovskite catalysts for the catalytic flameless combustion of methane Preparation by flame-hydrolysis and charaeterisation by TPD-TPR-MS and EPR. Appl. Catal, B Environmental, 2000, Volume 28, Issue 1, 55-64. 

Rossetti, 1. and Forni, L. (2001) Catalytic flameless combustion of methane over perovskites prepared by flame hydrolysis. Appl Catal B, 33 (4), 345-352. 

Forni and Rossetti studied Lao-oCeo-iCoOs+a perovskites prepared by the flame hydrolysis (FH) method [27]. This was proved a high-surface-area, thermally resistant catalyst The partial substitution of La by Ce in such a cobaltite led to a relatively low suprafacial activity, but to a high bulk oxygen mobility, leading to high intrafacial activity for the catalytic flameless combustion of methane. 

Leanza, R., Rossetti, I., Fabbrini, L., et al. (2000). Perovskite Catalysts for the Catalytic Flameless Combustion of Methane - Preparation by Flame-hydrolysis and Characterisation by TPD-TPR-MS and EPK.Appl. Catal. B Environ., 28, pp. 55-64. 

In gas technologies, premixed surface burners reduce NOx levels to a value not reachable with low NO diffusive flames, but this is at the expense of higher levels of CO and excess of air. The two main technologies that promise a future reduction in NO and CO values are the catalytic combustion [8] and the flameless combustion. 

Catalytic or flameless combustion of hydn en exhibits many advantages in comparison with flame combustion. It occurs at low temperatures (ambient - 800 K), is safe and leads to a very high conversion of the burning gas (99.9 %). The NOX formation which usually occurs in conventional combustion at temperatures of about 1700 K, is here almost completely suppressed. The catalytic combustion in diffusion burners (Fig. 7-2) occurs in the presence of small amounts of Pt or Pd catalysts. It is adequate, e.g., for kitchen appliances such as cooker, oven, water heater, space heater. Drawbacks are the possible non-uniformity of the temperature distribution at die catalyst surface, rapid changes in the operational state, and relatively small heat flux densities [47]. 

High-temperature catalytic combustion of gas and liquid fuels (Table 6) even in catelyst-supported regime (flame is located within La-Mn- monolith) sharply decreases emissions of NO and CO as compared with an open flame r ime. Earlier [11], such results were achieved only with Pd catalysts supported on metal monolith carrier. Flameless combustion on our catalysts appears to be even more efficient to abate NO j. The catalysts worked for two months without loss of activity and monolith integrity withstanding everyday start-ups and shut-offs. 

No catalytic wet oxidation with steam generation followed by aerobic polishing is an aqueous-phase flameless combustion technique that is usually run under severe conditions such as elevated temperature, pressure and residence time. 

Many modern technological processes are supplied with energy by combustion of organic fuels. Economically effective and ecologically clean installations with fluidized bed of the catalyst for flameless combustion were being developed within the last years. Highly effective apparatuses of this type are the Catalytic Heat Generators (CHG) developed by the Institute of Catalysis (Siberian Branch of the USSR Ac. Sci.) ... 

Xonon Cool Combustion A catalytic technology that combusts fuel flamelessly. Incorporated inside a gas turbine engine, it reduces the production of oxides of nitrogen to < 3 ppm by volume. Developed by Catalytica Energy Systems, CA. First demonstrated in 2002 in cooperation with Kawasaki Gas Turbines-Americas in Sonoma. The development was abandoned in 2006 because of unfavorable gas-turbine market conditions. 

The maximum temperature attainable in the combustor can be controlled by varying the air/fuel ratio. This is a unique feature of the catalytic combustor, since without a catalyst a flame can only be sustained in a narrow air/fuel ratio range. By using an appropriate catalyst, instead of operating at the typical temperature of conventional flame combustion (i.e. 1500°C), the combustor can operate under flameless conditions below 1300°C. It is well known that the... 

Catalytic Combustion. Catalytic combnstion is a process by which a lean fuel-air mixture is passed over a catalyst to flamelessly initiate combustion. The air and fuel are premixed upstream of the catalyst. A portion of the fnel is burned in the catalyst and the balance is burned downstream of the catalyst. This technique allows combustion temperatures to remain below 2730°F (1500°C), which is below the optimum temperature for production of thermal NO r (the nitrogen and oxygen in the air react to form NO r). The result is very low NO r emissions, on the order of 3 ppm. The technology is being demonstrated on a gas turbine and has been deemed by EPA to have proven that the reductions have been achieved in practice. 

Parameter Condensation Absorption Adsorption Regenerative Incineration oxidation Catalytic oxidation Flameless oxidation BIF combustion Biofiltration Flares... 

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