Flameless Burner Research Articles

Catalytic oxidation of natural gas using flameless burners of a new design

Various aspects of operating burners traditionally used for oxidizing gaseous hydrocarbons and heat exchangers used for heat recovery are considered. A method developed by FAST ENGINEERING LTD. for the efficient burning of fuel with deep heat recovery of waste gases while maintaining a given adiabatic temperature is described. The method is based on using a flameless burner and heat exchangers of a new design. Burner operation is tested on an experimental stand with determination of the dependences for the aerodynamic drag of a granular layer and the content of unburned hydrocarbons, CO, and NOx in combustion products on the consumption of the fuel-air mixture and the adiabatic temperature of fuel combustion. The described method for burning fuel is shown to provide the desired temperature of combustion products for a consumer of heat energy and to reduce the consumption of fuel by 5–20%. Burning fuel at an adiabatic combustion temperature of no more than 1200°C virtually eliminates the CO and NOx content in the combustion products. Designed flameless burner, new generation of heat exchangers, and technology for the efficient burning of fuel can be applied to vapor and water-heating boilers, gas turbines, and catalytic reactors to produce synthesis gas from natural gas for processing into hydrogen, ammonia, methanol, synthetic liquid hydrocarbons, and so on.

Effective fuel burning in flameless burners with maintenance of a prescribed adiabatic combustion temperature

Burners used traditionally for oxidizing hydrocarbons are considered. A method developed by FAST ENGINEERING is presented for effective fuel burning with thorough flue gas heat recuperation and stable maintenance of a prescribed adiabatic combustion temperature on the basis of using heat exchangers and flameless burners of a conceptually new design.

Experimental and numerical investigation of a micro-CHP flameless unit

A numerical and experimental investigation of a system for the micro-cogeneration of heat and power, based on a Stirling cycle and equipped with a flameless burner, is carried out with the purpose of evaluating the system performances with hydrogen-enriched fuels. The numerical model of the combustion chamber gave significant insight concerning the analysis and interpretation of the experimental measurements; however it required considerable efforts, especially regarding the definition of proper boundary conditions. In particular a subroutine was developed in order to couple the oxidation process to the overall operation of the micro-cogeneration unit. This procedure was proved to perform satisfactory, providing values of the heat source for the Stirling cycle that lead to expected thermal efficiencies in agreement with those indicated in the literature for similar systems. The importance of a proper turbulence-chemistry interaction treatment and rather detailed kinetic schemes to capture flameless combustion was also assessed. A simple NO formation mechanism based on the thermal and prompt routes was found to provide NO emissions in relatively good agreement with experimental observations when applied on thermo-fluid dynamic fields obtained from detailed oxidation schemes.

Performance of a Flameless combustion furnace using biogas and natural gas

Flameless combustion technology has proved to be flexible regarding the utilization of conventional fuels. This flexibility is associated with the main characteristic of the combustion regime, which is the mixing of the reactants above the autoignition temperature of the fuel. Flameless combustion advantages when using conventional fuels are a proven fact. However, it is necessary to assess thermal equipments performance when utilizing bio-fuels, which usually are obtained from biomass gasification and the excreta of animals in bio-digesters. The effect of using biogas on the performance of an experimental furnace equipped with a self-regenerative Flameless burner is reported in this paper. All the results were compared to the performance of the system fueled with natural gas. Results showed that temperature field and uniformity are similar for both fuels; although biogas temperatures were slightly lower due to the larger amount of inert gases (CO 2) in its composition that cool down the reactions. Species patterns and pollutant emissions showed similar trends and values for both fuels, and the energy balance for biogas showed a minor reduction of the efficiency of the furnace; this confirms that Flameless combustion is highly flexible to burn conventional and diluted fuels. Important modifications on the burner were not necessary to run the system using biogas. Additionally, in order to highlight the advantages of the Flameless combustion regime, some comparisons of the burner performance working in Flameless mode and working in conventional mode are presented.

Industrial applications of Tenova FlexyTech®flameless low NOx burners

Environmental emissions constraints have led manufacturers to improve their low NOx recuperative burners. The development by Tenova of the FlexyTech® Flameless burners with low NOx emissions, even below the present “Best Available Technology” limit of 40 ppm at 3%O2 with furnace temperature 1250°C, air preheat 450°C, is described. The results achieved during the R&D programme have been also improved in the industrial installations. Some details and performances of the recent furnaces equipped with such burners are provided.

Mild combustion in a laboratory-scale apparatus

Mild oxidation is one of the promising techniques proposed to control pollutant emissions from combustion plants. It is characterized by high preheating of combustion air and massive recycle of burned gases before reaction. These requisites lead to high combustion efficiency and good control of thermal peaks and hot spots, lowering NO x thermal emissions. In this work, a laboratory-scale burner for mild combustion, which is an apparatus characterized by high internal recycle ratio, high back-mixing, and thepossibility of also simulating external recycles of burned gases, is described, as well as the main experimental results achieved. These were carried out to demonstrate the possibility of reproducing the main phenomena observed in real-size flameless burners. Operating conditions for obtaining stable "mild" combustion with methane and ethane as fuels were investigated and operating parameters maps were obtained.

Heating without Pollution: The Flameless Burner

Heating without Pollution: The Flameless Burner

Using gas flameless panel burners in a tunnel kiln

Using gas flameless panel burners in a tunnel kiln

Analytical and experimental investigation of cupshaped flameless burners

Analytical and experimental investigation of cupshaped flameless burners