Auxiliary burners

Other systems such as the oxidation of H2S to SO2 and H2O are also used even though the SO2 produced is still considered a pollutant. The tradeoff occurs because the SO2 is much less toxic and undesirable than the H2S. The odor threshold for H2S is about three orders of magnitude less than that for SO2. for oxidation of HjS to SO2, the usual device is simply an open flare with a fuel gas pilot or auxiliary burner if the H2S is below the stoichiometric concentration. 

If low-cost natural gas is available, a gas turbine can be used to generate power. In this case, the waste heat in the exhaust gas is used to produce steam in a heat recovery boiler (HR boiler). This approach also is used with some gas turbine plants (as in some high-speed navy vessels). Where an HR boiler is employed, if steam demand exceeds power demand, the boiler is fitted with auxiliary burners. 

Any hydrogen-rich fuel not used in the fuel cells is returned to the reformer burner. The pressurized exhaust gases from the reformer burner are expanded in a turbocompressor, which compresses the process air to about 17 psig (2.4 atm). Process air is distributed to the fuel cell power sedion. to the reformer burner, and to an auxiliary burner. 

The combustion process proceeds in two stages in the primary section the solid phase bums and volatile gases are driven off in the secondary section, these volatile gases are burned. The combustion of refuse wastes often requires an auxiliary burner to maintain sufficient temperature for complete combustion. Large amounts of excess air, as high as 300%, are frequendy used. 

Regulations require that the incinerator furnace be at normal operating conditions, including furnace temperature, before hazardous wastes are injected. This requires auxiliary fuel burners for furnace preheating. In addition, the burners provide heat when the wastes burned are of low heating value. Auxiliary burners are sized for conditions where liquid wastes are injected without the addition of high heating value wastes. 

The earlier plants operated at deficit, and needed an auxiliary boiler, which was integrated in the flue gas duct. Auxiliary burners in tunnels or flue gas duet were additionally used in some instances. This situation was partially caused by inadequate waste heat recovery and low efficiency in some energy consumers. Typically, the furnace flue gas was discharged in the stack at rather high temperature because there was no air preheating and too much of the reaction heat in the synthesis loop was rejected to the cooling media (water or air). In addition, efficiency of the mechanical drivers was low and the heat demand for regenerating the solvent from the C02 removal unit (at... 

A traditional propane burner of WS was modified for BCO combustion. The burning chandwr with the modified burner was pre heated up to 900°C with an auxiliary burner placed opposite to the BCO atomiser (Fig. 5). The nozzle was cooled down to 30°C. Once 900°C was reached in the burning chamber, the BCO injection was started. After the ignition of BCO, which occurred immediately with supply of the first amount of BCO, the auxiliary burner was turned off. The supply of BCO was started with about 2 1/h and than increased to about 9-10 1/h (liquid pressure 0.9 bar). The air supply was adjusted to about 3% O2 in the flue gases. The burning of BCO in FLOX mode continued stationary without any difficulties for several hours. Table 1 summarises the main experimental results. 

After preheating the burning chamber up to 800-850 "C with an auxiliary burner, the BCO ignition and combustion were carried out without any difficulties. 

Fluorinated metal hydride (FI MH) purification options achieve very high hydrogen recovery rates compared with a PSA but dehydriding energy requires an auxiliary burner for use with steam reformers, raising energy consumption. 

Autothermal reformers have enough waste heat to significantly reduce or eliminate an auxiliary burner for use with FI MH systems, provided a significant fraction of the waste... 

In the early 1980s the preheater rotary kiln size reached a typical capacity of about 3000 (m)tpd. Further increasing of fhe oufpufs were limifed by a span life of fhe brick refractory lining of a rofary kiln shell wifh a diameter more of 6 m. The precalciner/preheater kilns were developed to reach production up to 10,000 (m)tpd and more, by splitting the total fuel input between the main burner and the auxiliary burners of an additional vertical vessel, called precalciner, located in between the rotary kiln section and the suspension preheater. 

The preliminary experimental campaign was focused on the establishment of the kiln base line in terms of NO production with its original monochannel burner 80% of total heat input was supplied by the main burner and the rest through the auxiliary burner installed on the Lepol grate. 

The green delayed petroleum coke has been used both for main and auxiliary burners with the mass flow rates of 7.64 t/h and 2.11 t/h, respectively (see Table 31.24). Total heat consumption is 791 kcal/kg cli and 21.6% of heat is shared at the auxiliary burner. 

For materials that excessively drip, auxiliary burner is used. 

The combustion temperature in the first chamber can be 800-1600 C (preferably 1000-1300 C) this is maintained by an auxiliary burner. The fuel-air mixture is adjusted so that an oxygen content of 0.1-11 vol% (preferably 0.5-5 voI%) is measured in the reaction gases at the exit of the first combustion chamber. 

A major problem with pelletizing plants is the NOx formed by the very high temperatures developed in the burners and heating chamber above the pellet bed. After the process reaches 1400 F (760 C), low NOx fuel injectors could be used above the beds to avoid the very high reaction temperature in the burners. To get the combustion chamber to 1400 F would require low NOx auxiliary burners. This technology has been used in many industries with excellent results. The NOx-forming temperature is lowered in the main combustion chamber by two major effects ... 

The same method is adapted in ISO DP 8887-1984 with particular reference to the expanded plastics, using specimens with thickness of 25 or 10 mm when the density of the material is below 100 kg/m or between 100 and 1000 kg/m respectively. The standard specimen size of 25 mm x 25 mm x 6 mm is used only for solids or foams with a density above 1000 kg/m. Highly dripping materials require an auxiliary burner directed at the collected melt causing it to burn away in order to obtain realistic information about the smoke formation. 

Auxiliary Burners Incineration plant shall be equipped with at least one additional... 

Ambient air (stream 200) is compressed in a two-stage compressor with intercooling to conditions of approximately 193 °C (380 °F) and 8.33 atmospheres (122.4 psia). The majority of the compressed air (stream 203) is utilized in the fuel cell cathode however, a small amount of air is split off (stream 210) for use in the reformer burner. The spent oxidant (stream 205) enters a recuperative heat exchange before entering a cathode exhaust contact cooler, which removes moisture to be reused in the cycle. The dehumidified stream (stream 207) is again heated, mixed with the small reformer air stream, and sent to the reformer burner (stream 211). The reformer burner exhaust (stream 300) preheats the incoming oxidant and is sent to the auxiliary burner, where a small amount of natural gas (stream 118) is introduced. The amount of natural gas required in the auxiliary burner is set so the turbine shaft work balances the work required at the compressor shaft. The cycle exhaust (stream 304) is at approximately 177 °C (350 F). 

The natural gas burner is designed for a turndown ratio of 30 1, so that the kiln can, thanks to this range of firing control, be started up from cold without any need for auxiliary burners. 

Proper introduction of the off-gas into the afterburner shall ensure good mixing with the secondary air. In order to obtain sufficiently high temperatures the afterburner chamber should be provided with an auxiliary burner. 

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