Abstract: In a low NO.sub.x emission incinerator a refuse supply stoker (1), a dry-ignition stoker (2), a gas generation stoker (3), and a complete combustion stoker (4) are positioned in descending stair-step fashion beneath a combustion chamber (A). In the dry ignition stoker (2) and the gas generation stoker (3) refuse is thermally decomposed under an amount of air which is less than the amount of air theoretically required for complete combustion, so that reducing gases such as CO, NH.sub.3, and the like are generated. At the complete combustion stoker (4) the residuum of the refuse is completely combusted under an amount of air greater than the required theoretical amount. Air is supplied through nozzles (7,8,9) at successive points above the flow route of combustion gas inside the combustion chamber (A) so that the temperature in the combustion chamber (A) is maintained in a range to reduce the amount of NO.sub.x generated by the combustion of gases.

Abstract: An improved heating unit comprises a combustion chamber which includes a fuel-supporting perforated burning platform located a distance from the bottom of the combustion chamber. A perforated air plenum is disposed within the combustion chamber a short distance from the combustion chamber top wall to overly a portion of the burning platform. A blower forces air upwardly through the perforations in the burning platform to facilitate waste material combustion and the blower also forces air downwardly through the plenum perforations against the burning platform to further oxygenate the flames and thereby achieve nearly complete combustion. The pressure of incoming air into the combustion chamber forces the exhaust gases through the air passageway above the plenum and out through an exhaust pipe. A heat exchanger, taking the form of a water jacket, surrounds the combustion chamber to cool the combustion chamber and to recover the heat radiated upon combustion of the waste combustible material.

Abstract: A method for controlling two-stage combustion furnaces having a first stage operated with sub-stoichiometric airflow and a second stage operated with excess air, whereby the first stage airflow is controlled such that the ratio of first stage airflow to total airflow is maintained less than ##EQU1## where N lies between zero and unity.

Abstract: Method and apparatus for controlling the distribution of secondary air (30) between at least two fuel burners (14,16) in a multiple fuel combustor (16). Total chemical energies of the individual fuel streams (44,60) are determined and compared (64,66) with the total combustor chemical energy input (62) for controlling biasing means (32,34). The determination of at least one individual fuel total chemical energy content (60) may optionally include a prompt neutron activation type analyzer (48) for on-line measurement of specific fuel chemical energy (59).

Abstract: The present invention relates to a method for efficiently incinerating waste material, particularly dewatered sludge, in a multiple hearth furnace by controlling the temperature of the individual hearths of the furnace within certain prescribed limits by modulating the amount of combustion air, and controlling the temperature of the afterburner or combustion hearths to within certain prescribed limits by splitting the feed sludge between the first two upper waste material handling hearths.

Abstract: In order to protect a boiler against overheating a boiler draft control device comprises a safety thermostat in addition to the regular control thermostat. The control thermostat is provided with a supporting tube in order to limit its length reduction in the event of its failure. The safety thermostat is designed in such a manner that its working element only provides a displacement when the control range of the control thermostat is exceeded. Furthermore the safety thermostat has a very steep displacement/temperature characteristic and its maximum stroke is equal or greater than the stroke being given by an operable control thermostat over its total control range. A latch means is provided to prevent that an air inlet flap closed according to the response of the safety thermostat may be opened again with the cooling down of the boiler.

Abstract: A fluidizing gas control apparatus for a fluidized-bed incinerator, in which a variation of the pressure loss of fluidizing gas flowing through a fluidized bed formed by a fluid-forming medium is measured, while progressively increasing the flow rate of fluidizing gas supplied to the incinerator in the starting stage, to determine the optimum value of the flow rate of fluidizing gas on the basis of the measured variation of the pressure loss, and the sum of the flow rate of fluidizing air and the flow rate of recirculated gases provided by recirculation of a portion of exhaust gases is controlled to be maintained at the optimum flow rate throughout the incinerating operation of the incinerator.

Abstract: A method of firing a pulverized fuel-fired steam generator furnace wherein a mixture of recirculated cleaned flue gas and air is supplied to the mill for drying the pulverized fuel in the mill and transporting the pulverized fuel to the furnace. The volume flow rate of the gaseous mixture of recirculated flue gas and air is controlled in response to the feed rate of fuel to the mill to maintain a mixture to fuel ratio in the transport stream of about but not less than 1.5. The volume flow rate of recirculated flue gas with respect to the volume flow rate of air is controlled to maintain the oxygen content of the gaseous mixture at a level of at least 12% by volume and preferably in the range of 12 to 15% by volume.

Abstract: A process is provided for burning refuse containing polyvinyl chloride without the consequent production of phosgene. The refuse is carbonized in a rotary furnace at temperatures below 1200 degrees F., especially 700 degrees F., in an oxygen deficient atmosphere. A burnable gas containing the carbonized refuse is drawn from the furnace by an air jet wherein same is mixed with oxygen and selectively combusted. Uncarbonized refuse is collected and withdrawn after exiting the furnace. An apparatus is provided for combustion of the refuse in the nonphosgene generating process and includes the rotary furnace. Special seals are provided for the furnace to prevent excess oxygen from entering thereinto. In particular, the seals are utilized between the rotary ends of the furnace and stationary head associated with each end respectively.

Abstract: A method and system for controlling the combustion of, for example, coal or bark in a stoker boiler or black, liquor in a recovery boiler to provide operation at maximum efficiency. Control loops are provided for primary or undergrate air and secondary or overfire air. The undergrate air control loop is adjusted as a function of carbon dioxide or steam/fuel ratio, and the overfire air control loop is adjusted as a function of carbon monoxide. In addition to carbon monoxide, combustibles and opacity may be used. Air redistribution is also used to minimize combustibles or CO or opacity.

Abstract: In a recovery boiler having a plurality of air inputs, with the primary air input closest to the bed of the boiler, a fuel input, a smelt output, and an exhaust output, a method of controlling the combustion of fuel in the boiler to operate at the maximum reduction efficiency. The method includes the steps of measuring the amount of sulphur dioxide at the exhaust output; and varying the amount of air entering into the boiler through the primary air input until the minimum amount of sulphur dioxide is measured at the exhaust output.

Abstract: A method of controlling the opacity of the exhaust of the combustion of solid fuel and air in a furnace comprises measuring the opacity of the exhaust. The amount of air and the direction (i.e., increase or decrease) entering into the furnace is changed. The opacity of the exhaust is measured again. The later measured value of opacity is compared to the earlier measured value. The amount of air entering into the furnace is controlled based upon the comparison.

Abstract: A method and apparatus for the heat treatment of industrial wastes wherein at least some of the constituent materials of the wastes are subjected to combustion and/or to pyrolysis to produce flue gases and, in some applications, a residue. The supply of an oxygenated combustion-supporting gas to the wastes is regulated as a function of at least one sensed predetermined characteristic of the flue gases. The oxygenated gas may be a mixture of air and substantially pure oxygen, the feed rate of one or both of these being regulated in response to the sensed temperature and/or oxygen content of the flue gases. Such regulation maintains the oxygen content of the flue gases within the range of from 0 to 7%; and the temperature of the flue gases may be maintained from 400.degree. to 1200.degree. C. and, preferably within a range of 50.degree. C. in this region.

Abstract: Control method and apparatus for optimizing the operation of a natural draft combustion zone through which a conduit containing a process fluid to be heated passes, by decreasing the supply of combustion air until one or more of the following predetermined limiting conditions is reached: maximum CO in the flue gas, minimum O.sub.2 in flue gas, minimum draft in the combustion zone, maximum temperature of the outer surface of said conduit, and increase in the rate of fuel addition above a minimum amount. When a limiting condition is reached, the supply of combustion air is increased until the limiting condition is no longer present, and the cycle then repeated.

Abstract: An air-curtain incinerator for burning energetic materials. Both the volume f air and the angle at which air enters the fire box are remotely controllable. The combustion process is monitored, and the air volume and angle at which air enters the fire box are controlled to minimize the production of air pollutants by the combustion of energetic materials.

Abstract: Control method and apparatus for optimizing the operation of a natural draft combustion zone through which a conduit containing a process fluid to be heated passes, by decreasing the supply of combustion air until one or more of the following predetermined limiting conditions is reached: maximum CO in the flue gas, minimum O.sub.2 in flue gas, minimum draft in the combustion zone, maximum temperature of the outer surface of said conduit, and increase in the rate of fuel addition above a minimum amount. When a limiting condition is reached, the supply of combustion air is increased until the limiting condition is no longer present, and the cycle then repeated.

Abstract: A water heating stove, comprises a fire box substantially surrounded by a water jacket through which water to be heated circulates. The fire box is completely closed by sealing, loading and clean out doors, to provide that the only access for combustion air is a special aperture below the fire, controlled by a thermostatically operated damper. The fire box bottom wall is inclined to allow drainage of water condensates without losing combustion air flow control, via a water trap. The stove includes a heat transfer coil through which water is circulated to supply hot water.

Abstract: In a home heating system having a furnace with a combustion chamber for burning fuel and creating heat, and a chimney with a draft therein, an improvement comprising, an exhaust flue connected between the combustion chamber and the chimney for venting heated exhaust products from the furnace, a heat reclaimer connected into the exhaust flue between the combustion chamber and the chimney for reclaiming heat from the heated exhaust product, and an outside air line for supplying air from the outside of the house to the combustion chamber. A first flue portion of the exhaust flue is connected between the combustion chamber and the heat reclaimer, and a second insulated flue portion of the exhaust flue is connected between the heat reclaimer and the chimney. An outside air by-pass or balancing line is connected between the outside air line and the chimney for satisfying the chimney suction at flame-out.

Abstract: The following disclosure teaches ways and means for incinerating organic materials in a multiple hearth furnace equipped with an afterburner. In the furnace, the wastes are pyrolyzed in an oxygen deficient atmosphere which is regulated to only partially complete the oxidation of the organic substances which are pyrolyzed from the wastes. In the lower part of the furnace fixed carbon is substantially burned. In the afterburner, air is introduced to complete the oxidation of the partially oxidized substances carried by gases and vapors from the furnace. The air supply to the afterburner is controlled so that, at temperatures above a predetermined temperature, the quantity of air introduced is increased with increasing temperatures and is decreased with decreasing temperatures.