Abstract: A method of controlling combustion in a furnace of a boiler or the like having a burner for a main combustion and a burner for a reducing combustion in order to effect combustion for furnace denitrification. The method comprises the steps of: estimating the NO.sub.x generation amount from data on a flame formed by the main combustion; estimating the reducing agent generation amount from data on a flame formed by the reducing combustion; and controlling the flow rates of fuel and air supplied for the main and reducing combustions so that the amount of NO.sub.x emission as the difference between the NO.sub.x generation amount and the reducing agent generation amount is below a specified value. In practice, each of the NO.sub.x generation amount and the reducing agent generation amount is estimated from the flame pattern, the flame volume, the distance between the outlet of the burner concerned and the root of the flame concerned, etc.

Abstract: Exhaust gas treatment method and apparatus extract heat from an exhaust gas by operating in a water-condensing mode which allows more heat to be recovered, removes particulate matter and condensed acid from the exhaust gas, and washes heat exchange surfaces to keep them clean and wet to improve heat transfer. Systems for heating water, air, and both water and air are disclosed. Methods of constructing and assembling improved heat exchangers are disclosed.

Abstract: A process uses limestone injection into a combustion boiler burning pulverized coal or liquid hydrogen fuel. Effluent gas from the boiler is humidified and cooled to below 200.degree. F. During the humidifying and cooling step, sulfur dioxide removal occurs in addition to that which takes place in the combustion zone of the boiler. The effluent gas and unreacted alkali is then fed into an electron beam irradiation chamber which produces energetic conditions for rapid reaction of sulfur dioxide and nitrogen oxides in the presence of water vapor. The remaining unreacted alkali reacts rapidly and in-situ with the sulfuric acid and nitric acid formed in the electron beam chamber.

Abstract: In a method for desulfurizing flue gas generated in coal combusting plants, the coal is burned in the presence of a dry additive material, such as CaCO optionally in presence of recycled cold flue gas whereby additive material which has not reacted is discharged together with the flue gas from the firing space and is separated together with the ashes in dust filters. The relative moisture of the flue gas is increased before entering the dust filter so that the sulfur compounds in the flue gas react to a greater extent with the additive material in the dust filters. The device for practicing this method comprises a heat exchanger and/or an injection cooler arranged streamup of the flue gas filtering installation.

Abstract: A method of operating a fluidized bed in which a bed of particulate combustible material and adsorbent material are disposed on a perforated plate. Air is introduced through said plate and into said bed to fluidize and promote the combustion of the combustible material, and a gaseous agent is injected into the bed to stabilize the surface hardness, sulfur-absorption properties and catalytic properties of said adsorbent material.

Abstract: The formation of slag is minimized and the removability of slag is greatly increased, in connection with the furnace burning of black liquor, by applying to the surfaces where slag tends to form a substance which, under black liquor furnace conditions, reacts with the sodium sulfide content of the black liquor ash to oxidize said sodium sulfide and to be itself reduced, such substances preferably comprising sodium persulfate, manganese dioxide, cupric oxide and ferric oxide and mixtures thereof.

Abstract: A method of improving the efficiency of large industrial boilers of the type using heat exchangers heated by superheated steam diverted from the steam used to produce energy, which heat exchangers elevate the temperature of the air heater section of such boilers to minimize corrosion caused by the condensation of SO.sub.3 to produce sulfuric acid which comprises reducing the temperature of the air heater by throttling the steam fed the heat exchanger while, at the same time, using an amount of sulfuric acid neutralizing chemical in the air heater section of such boilers to neutralize any increase in the sulfuric acid formed.

Abstract: An improvement in a condensing furnace where gaseous products of combustion are ducted through fin tube condensers that act to heat incoming air. The improvement involves spraying water into the products of combustion upstream of the fin tube condenser, so that the sprayed water droplets mix intimately with the products of combustion and are thus vaporized. In this manner, the combined water vapor and gaseous combustion products can condense in the fin tube condenser to create a liquid condensate of which the pH is closer to neutral than would have been the case in the absence of the sprayed water.

Abstract: The performance of a slagging coal gasifier is improved by injecting finely divided particles of noncorrosive slag-like solid material into the gasifier near the zone of combustion at a rate at which heat-protective layers of solidified slag are maintained between that zone and metallic materials located near that zone.

Abstract: A method of increasing the efficiency of a cyclone-fired boiler which uses high sodium lignite as fuel. The fuel produces ash deposits on heat transfer surfaces within the boilers, and in accordance with the method, powdered limestone is periodically injected into the firebox of the boiler in a quantity and for a time period such that the limestone is heated to a temperature in the range of from about 2200.degree. F. to about 2700.degree. F. and reacts with ash deposits in the boiler to form layers thereon. The layers so formed have a higher ash fusion temperature than the unreacted deposits and cause the resulting composite deposit to be more friable whereby the deposit can be removed using conventional soot blower apparatus.

Abstract: In a coal fired boiler of the type having a combustion zone in which said coal is fired, a convection zone located downstream from said combustion zone and having a plurality of heater tubes disposed therein adapted to heat water or steam disposed therein, and in which convection zone combustion residues emanating from said coal have a tendency to stick to or agglomerate upon said tubes, a method of decreasing said tendency to stick or agglomerate, comprising burning said coal in the presence of an additive consisting essentially of amorphous silica particles, substantially all of said particles being greater than about 38 microns in diameter.

Abstract: A method of continuously introducing additive, which is conveyed by gaseous and/or liquid carriers, into a turbulent reaction gas flow in the combustion chamber of a steam generator having dry ash withdrawal for selective removal, in a dry manner, of environmentally harmful gaseous noxious materials, such as sulfur, chlorine, and chlorine compounds, which are contained in a hot reaction gas flow which results after a complete or incomplete flame combustion of solid, liquid, or gaseous fuels. Depending upon the additive introduced, heat is stored and/or used for decomposition reactions. The additive, is first introduced at one or more input locations, due to locally different pressure conditions in the combustion chamber, into one or more recirculation flows which are within the system and are closed. The additive is subsequently withdrawn from these recirculation flows and is introduced into the reaction gas flow.

Abstract: A process for cleaning surfaces of installations fouled by products of combustion of carbon-bearing materials, such as in particular boiler combustion chambers, rotary or static heat exchangers, combustion product ducts and flues, electrostatic filters, etc., which are to be cleaned without having to stop the combustion process, in order to maintain maximum thermal efficiency in order thereby to make a substantial energy saving, in which an aqueous solution of ammonium nitrate and potassium nitrate is injected into the installation, the deposited substances being detached from the installation by means of sound sources.

Abstract: A method and composition are described for carrying out the combustion of fossil fuels in a fluidized bed with reduced emissions of sulfur, carbon and nitrogen oxides and unburned hydrocarbons. Combustion is carried out in the presence of a solid sulfur oxide adsorbent and a metal or metal oxide component which is catalytically active with respect to unburned hydrocarbons, carbon monoxide and nitrogen oxide.

Abstract: A process for the desulfurization of coal and apparatus for carrying out the process. The process includes the steps of: first, treating dry coal particles with dry chlorine gas; and, second, treating the coal particles with a purging gas. The purging gas may be, for example, dry steam or an inert gas, such as nitrogen or carbon dioxide. The apparatus includes a chlorinator means for treating the dry coal particles with dry chlorine gas and a stripper means for treating the coal particles with a purging gas.

Abstract: The present invention provides a method for reducing slag build-up in cyclone furnaces comprising introducing into a cyclone furnace at least one of a slag viscosity modifier and a combustion adjuvant, wherein a substantial portion thereof is conveyed to the walls of the furnace by addition through the secondary air stream. Preferably the additives are formed as particles of sufficient size and density that they are driven directly to the walls of the furnace. This method alleviates slag build-up caused by the presence of uncombusted coal particles at the walls and increases the temperature environment at the walls.

Abstract: Slag buildup in high-temperature areas of a furnace system is minimized by adding to the molten ash particles carried by the flue gas a conditioner which is taken up by those molten particles and produces a nucleating effect when those particles cool, causing them to solidify more rapidly, thereby preventing deposit formation or resulting in considerably more friable deposits.

Abstract: Uncalcined vermiculite is injected into the coal fired furnace, at 3000.degree.-1200.degree. F., thereby facilitating removal of deposits that accumulate on line within the furnace.

Abstract: Apparatus and methods for fluidized bed incineration of waste containing phosphorus wherein the bed comprises lime or limestone which negates heretofore existing problems incident to the presence of phosphorus.

Abstract: A continuous process for the combustion of solid fuels in the presence of strong sulfuric acid under conditions such that oxides of nitrogen are not formed and oxides of sulfur and particles of ash are effectively prevented from contaminating the gaseous products released to the atmosphere.

Abstract: The process of this invention provides for reducing the tendency of a carbon monoxide gas stream, containing a minor level of elemental phosphorus, to corrode metallic surfaces in a combustion zone upon combustion of the gas stream in the combustion zone to combustion gases. The process comprises, prior to combustion:(a) cooling the gas stream to a sufficiently low temperature to condense a quantity of elemental phosphorus to produce a reduced level of elemental phsophorus in the gas stream; and(b) diluting the gas stream with an effective amount of combustible gas, wherein the effective amount of combustible gas is an amount which is effective in producing a dew point of the combustion gases, with respect to the quantity of acid, e.g. meta-phsophoric acid (HPO.sub.3), produced by the combustion of the reduced level of elemental phosphorus, less than the temperature of the metallic surfaces.

Abstract: The process of this invention provides for reducing the tendency of a carbon monoxide gas stream, containing a minor level of elemental phosphorus, to corrode metallic surfaces in a combustion zone upon combustion of the gas stream in the combustion zone. The process comprises:(a) prior to combustion, cooling the gas stream to a sufficiently low temperature to condense a quantity of elemental phosphorus to produce a reduced level of elemental phosphorus in the gas stream; and(b) injecting into the combustion zone during combustion an effective amount of MgO or a compound capable of yielding MgO to neutralize the quantity of acid, e.g. meta-phosphoric acid (HPO.sub.3), produced by the combustion of the reduced level of elemental phosphorus.

Abstract: A method of preventing corrosion of incinerators designed to burn sewage sisting essentially of from about 90 to 98 percent water and from about 2 to 10 percent waste solids by increasing the fusion temperature range of the ash product above the operating temperature of the interior surfaces of the incinerator. The sewage is mixed with additive materials selected from the group SiO.sub.2, CaO, Al.sub.2 O.sub.3, MgO wherein the CaO, Al.sub.2 O.sub.3 and MgO are selected from within the range of 10 to 30 percent of the weight of the waste solids and the SiO.sub.2 is selected from within the range of 25 to 30 percent of the weight of the waste solids.

Abstract: An additive, e. g., MgO.Mg silicate, is injected into the flue gas stream of a coal-or oil-fired furnace, at 2300-1700 deg. F., thereby reducing accumulation of sulfuric acid on the air heater inlet and outlet.

Abstract: A method for disposal of sodium containing waste material comprising combustion sodium containing waste material and a silica bearing material in an incinerator having interior walls lined with a refractory material which tends to react with metallic sodium and deteriorate. The sodium containing waste material comprises sodium salt and/or bases and by providing reaction conditions whereby the metallic sodium tends to react with silica to provide a combustion product including a sodium silicate compound, the combustion is carried out in manner to reduce deterioration of refractory materials by reaction with metallic sodium. Also disclosed is a method for the simultaneous disposal of sodium containing waste material and rice hulls which contain silica and provide a portion of the combustion energy.

Abstract: The present invention is drawn to ethylene polyamines in combination with certain alkanolamines as cold-end additives. More specifically, it has been discovered that if these additives are fed to the moving combustion gases of a combustion system which uses sulfur containing fuel and upstream of cold-end surfaces to be treated, the additive will travel along with the gases as vapor and/or liquid droplets and deposit on the cold-end surfaces. As a result, the amount of sulfuric acid corrosion of metallic cold-end surfaces is reduced.

Abstract: A coal pump is provided in which solid coal is heated in the barrel of an extruder under pressure to a temperature at which the coal assumes plastic properties. The coal is continuously extruded, without static zones, using, for example, screw extrusion preferably without venting through a reduced diameter die to form a dispersed spray. As a result, the dispersed coal may be continuously injected into vessels or combustors at any pressure up to the maximum pressure developed in the extrusion device. The coal may be premixed with other materials such as desulfurization aids or reducible metal ores so that reactions occur, during or after conversion to its plastic state. Alternatively, the coal may be processed and caused to react after extrusion, through the die, with, for example, liquid oxidizers, whereby a coal reactor is provided. Alternative utilization of the device may be to secure continuous pyrolysis of the coal or to feed the extruded coal into furnaces operating at pressures near ambient.

Abstract: The present invention is drawn to ethylene polyamines in combination with certain alkanolamines as cold-end additives. More specifically, it has been discovered that if these additives are fed to the moving combustion gases of a combustion system which uses sulfur containing fuel and upstream of cold-end surfaces to be treated, the additive will travel along with the gases as vapor and/or liquid droplets and deposit on the cold-end surfaces. As a result, the amount of sulfuric acid corrosion of metallic cold-end surfaces is reduced.

Abstract: This invention constitutes improvement in the art of introducing fuel additives into the fireside of coal fired boiler tubes to facilitate the removal of slag and like deposits from the fireside, to lower acid smut pollution, to control corrosion, and to improve the electrical resistivity of particulate emission. The improvement is achieved by the addition of pulverized coal to the fuel additives.

Abstract: A method of reducing the amount of corrosion due to sulfuric acid on metal parts at the cold-end of a combustion system and in contact with combustion gases derived from the combustion of sulfur-containing fuel, said method comprising adding to the combustion gases an effective amount for the purpose of an ethylene polyamine additive.

Abstract: Sulfur-containing fossil fuels are combusted in the presence of calcium carbonate or calcium magnesium carbonate, whereby the sulfur oxides formed by combustion react with the calcium oxide or calcium magnesium formed from the carbonate during the combustion, thereby to form calcium sulfate or calcium magnesium sulfate. The sulfur oxide content of the combustion gas is thereby reduced. The calcium oxide or calcium magnesium oxide is removed from the combustion, and is slaked with water to form the corresponding hydroxide. This hydroxide is recycled to the combustion zone or to the combustion gases emanating from the combustion zone, whereby the quantities of the carbonate used in the combustion can be reduced.

Abstract: A method of reducing the amount of sulfur trioxide condensation on, and therefore the amount of sulfuric acid corrosion of, metal parts at the cold-end of a combustion system and in contact with combustion gases derived from the combustion of sulfur containing fuel, said method comprising adding to the combustion gases an effective amount for the purpose of an aliphatic, water-soluble alkanolamine additive.

Abstract: The amount of soot and slag formed during the combustion of carbonaceous waste material is appreciably reduced by combusting said waste material in the presence of at least 0.0001%, by weight, of sodium bentonite, based on the weight of carbonaceous material being combusted. The sodium bentonite may be added directly to the waste material before entering the furnace or the sodium bentonite may be added directly to the furnace.

Abstract: A method of reducing the amount of sulfur trioxide condensation on, and therefore the amount of sulfuric acid corrosion of, metal parts at the cold-end of a combustion system and in contact with combustion gases derived from the combustion of sulfur containing fuel, said method comprising adding to the combustion gases an effective amount for the purpose of an alkanolamine additive particularly N-aminoethyl ethanolamine.

Abstract: A method of reducing the amount of sulfur trioxide condensation on, and therefore the amount of sulfuric acid corrosion of, metal parts at the cold-end of a combustion system in contact with combustion gases derived from the combustion of sulfur-containing fuel, said method comprising adding to the combustion gases an effective amount for the purpose of an aqueous solution of sodium metasilicate and an alkanolamine, particularly N-aminoethyl ethanolamine.

Abstract: A method of reducing the amount of sulfur trioxide condensation on, and therefore the amount of sulfuric acid corrosion of, metal parts at the cold-end of a combustion system in contact with combustion gases derived from the combustion of sulfur-containing fuel, said method comprising adding to the combustion gases an effective amount for the purpose of an aqueous solution of sodium aluminate and an alkanolamine, particularly N-aminoethyl ethanolamine.