摘要:
An in-furnace method and apparatus reduces nitrogen oxides in flue gas by injecting an oil water emulsion into flue gas so that the oil and water mixes with said flue gas. The emulsion has from 35% to 80% water and is injected in sufficient quantities to provide enough oil to promote a reaction between the nitrogen oxides in the flue gas and the oil, so as to reduce nitrogen oxide content of the flue gas and to maintain overall fuel lean conditions above the primary combustion zone. The emulsion preferably is atomized before injection and may also be injected in jet streams. Other materials such as limestone, ammonia and urea could be added to the oil water emulsion prior to injection.
摘要:
In a method of reducing NO.sub.x a water-fixed nitrogen solution is injected into a furnace near the exit from the furnace where the temperatures exceed 2000.degree. F. and combustion is occurring. Preferably the solution is injected through a combination of atomizing nozzles and spray jets into a region of the furnace which does not exceed 2700.degree. F. A calcium compound to react with sulfur dioxide may also be added.
摘要:
In a method for reducing NOx in the flue gas a coal water slurry is injected into the furnace above the primary combustion zone into a region having a temperature from 1800.degree. F. to 2700.degree. F. The slurry is preferably injected through atomizers and through injectors that introduce a continuous stream. Lime, ammonia, urea and completion air can also be injected.
摘要:
A process for stabilizing sludge containing flyash and calcium sulfate formed by a lime or limestone scrubber increases the sludge particles to a size at which leaching of toxic metals from the particles no longer occurs at toxic levels. The sludge is dewatered and injected into the furnace in a manner to cause the flyash to soften and stick together. The agglomerated particles then fall into a bottom ash pit for removal as a common waste.
摘要:
An apparatus and method to improve pulverizer operation and reduce nitrogen oxide emissions from furnaces which burn pulverized coal from at least one pulverizer. A duct type burner burns a fuel in the primary air which heats the primary air supplied to the pulverizers. The combustion increases the primary air temperature and improves the drying of the coal, thus improving the pulverizer throughput and/or the fineness of the pulverized coal. Operation of the duct burner also reduces the oxygen in the primary air. The reduction in oxygen reduces the propensity of the coal to ignite in the pulverizers and cause fires or even explosions. The reduced oxygen in the primary air also reduces NO.sub.x formation.
摘要:
A combustible fuel containing 3% to 45% of the fuel needed to operate a gas turbine is introduced into the compressor air stream for the gas turbine. The mixed fuel and air stream is introduced to the gas turbine prior to the combustor stage through a pipe, orifice or nozzle. The mixed air and fuel stream serves to reduce the nitrogen oxide emissions of the gas turbine. Waste air streams such as mine ventilation air may be used as the mixed fuel and air stream.
摘要:
Disclosed is a process for combustion of carbonaceous substances containing ash and sulfur in slagging combustors wherein the fraction of sulfur retained in the slag is enhanced, emissions of nitrogen oxide are reduced, and operating problems with the furnace are avoided. The process comprises control of slag within a temperature range of 2000.degree.-2500.degree. F., slag stoichiometry less than oxidizing, and gas phase stoichiometry near stoichiometric.
摘要:
A method for reducing the rate of side wall corrosion in a coal-fired utility boiler. A plurality of side wall slots are provided in the side walls of the boiler so that a protective layer of air may be introduced through the slots and propelled upward by the updraft from the burners.
摘要:
An improved pulverized coal burner that reduces the formation of nitrogen oxides. The coal burner includes fuel splitters that separate a mixture of primary air and coal into a plurality of streams while the mixture is discharged through a diffuser having a plurality of partially open areas and a plurality of blocked areas. After passing through the diffuser, the plurality of streams are discharged into a furnace to be burned. The plurality of partially open areas and blocked areas are created by removing sections of the diffuser and replacing the removed sections with fuel spiders. Creation of these discrete streams delays mixing with secondary air. Because primary air is supplied in sub-stoichiometric quantities, the coal in these split streams will be burned under fuel-rich conditions for the first 100 to 200 milliseconds of combustion, until the delayed mixing of secondary air occurs. Combustion in a fuel-rich environment retards formation of nitrogen oxides in two ways. First, nitrogen that is part of the volatile matter that is evolved during the ears stages of combustion will tend to form molecular nitrogen rather than react with oxygen to form nitrogen oxides. Second, an oxygen deficiency will reduce formation of nitrogen oxides from atmospheric nitrogen. Two variations of bypass conduits are disclosed that allow a portion of the mixture of primary air and coal to bypass the diffuser and discharge into the furnace.
摘要:
The present invention provides an apparatus and method to improve the performance of a variety of particulate collection devices. Gaseous ammonia is injected by one or more injectors into a waste gas upstream from a particulate collection device. The amount of ammonia injected from each injector is controlled so that the local concentration of ammonia in the waste gas is approximately the same as the corresponding local concentration of sulfur trioxide in the waste gas. The flow of ammonia from each injector is controlled by measuring several local sulfur trioxide concentrations in the waste stream after the ammonia has been injected. The sulfur trioxide can occur naturally or result from injection. By keeping the concentration of ammonia approximately equal to the concentration of sulfur trioxide, ammonia and sulfur trioxide react to form a liquid product. This liquid reaction product coats the surfaces of particles entrained in the gas stream. Once coated, the particles' electrical conductivity is altered so that they are more easily collected by devices employing electrostatic attraction. The liquid coating also causes the particles to agglomerate and these larger agglomerates are easier to collect.