Burner fuels

Mu/tihearth Furnace. Multihearth furnaces are most often used for incineration of municipal and industrial sludges, and for generation and reactivation of char. The main components of the multihearth are a refractory-lined shell, a central rotating shaft, a series of soHd flat hearths, a series of rabble arms having teeth for each hearth, an afterburner (possibly above the top hearth), an exhaust blower, fuel burners, an ash removal system, and a feed system. 

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

Turbulence. Turbulence is important to achieve efficient mixing of the waste, oxygen, and heat. Effective turbulence is achieved by Hquid atomization (in Hquid injection incinerators), soHds agitation, gas velocity, physical configuration of the reactor interior (baffles, mixing chambers), and cyclonic flow (by design and location of waste and fuel burners). 

Prior to being fed to a pulverized fuel burner, coal is ground to a size generally specified such that at least 70% passes a 200 mesh screen (75 Tm) and less than 2% is retained on a 52 mesh screen (300 Tm). The top size is deterrnined by the classifying component of the cmshing mill, oversize material being retained for further grinding (54,100,101). 

Diesel Fuel Burner Fuel High-Ash Typical ... 

A direct-flame afterburner, in which an auxiliary fuel burner provides all the heat from a flame, or... 

Fluidized-bed process incinerators have been used mostly in the petroleum and paper industries, and for processing nuclear wastes, spent cook liquor, wood chips, and sewage sludge disposal. Wastes in any physical state can be applied to a fluidized-bed process incinerator. Au.xiliary equipment includes a fuel burner system, an air supply system, and feed systems for liquid and solid wastes. The two basic bed design modes, bubbling bed and circulating bed, are distinguished by the e.xtent to which solids are entrained from the bed into the gas stream. 

Pulverized fuel burners 1-50 All types including anthracite hgnite and bituminous <15 1 None Limited use in shell boilers mainly kilns and power stations... 

Initial preheating of the combustion chamber by gas or oil is normally required in order to provide the necessary temperature environment to release the volatiles that provide the stabilization in the base of the flame. Some small PF systems have used another fuel for flame support, but this compromises the economics. A typical pulverized fuel burner is shown in Figure 24.17. 

Fluid beds can be fired with gas and oil across the top of the slumped bed since sufficient freeboard exists with coal firing to prevent particle elutriation. Oil, gas or dual-fuel burners so arranged could also provide the means for bed preheating, especially if the flame is redirected down to the fluidization zone. 

Domestic Burner Control (Fuel Burners, Gas Condensing Boilers)... 

A 2-value smaller than 1 means that there is an excess of fuel in the mixture. In this case the air/fuel mixture is called rich. If more air is in the mixture than needed for a complete fuel combustion (2 > 1) the term lean mixture is used. Ideally the combustion is complete at 2 = 1. Real fuel cannot be combusted without an increase in CO and soot at 2-values smaller than 1.05. Due to changing operation conditions, for example a soiled burner, wear of the nozzle or leaky flaps, change of gas quality or changes of temperature and air pressure in the ambient atmosphere, the air/fuel ratio and thus flue gas composition can change over time. In order to minimize the risk of intoxication (see also chapter 5333), explosion and pollution real (uncontrolled) fuel burners are adjusted to operate far beyond this limit in the excess (lean mixture) region. However, unfortunately effi-... 

Carbon monoxide (CO) is generated in incomplete combustion processes. In households the main sources are all kinds of fuel burners (fuel oil, wood, natural gas, coal etc.) and automotive exhaust gas. Carbon monoxide is an odorless and invisible gas, and, due to its affinity to hemoglobin, which is higher than that of oxygen, it reduces the blood s capacity to carry oxygen. Hence it is toxic, especially for unborn and small children as well as for the elderly or people with heart problems or anemia. Even small amounts of CO can be harmful. Tab. 5.6 gives an overview of the relation between CO concentration and the corresponding symptoms of intoxication. 

Jet fuel, burner kerosene, heating oil, and heavy marine fuel oils do not typically contain detergents. The widespread need for detergents to improve fuel performance in these applications has not yet developed. Although in some small markets, combustion catalysts and burner nozzle antifoulants are utilized. 

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