Abstract: An air nozzle assembly for use in associated combustion apparatus which includes a first elongated housing having first and second axial extremities. The first axial extremity thereof is open to the interior of the first housing and tapers axially from a larger to a smaller cross section that constitutes a generally flat nozzle at the first axial extremity. A second elongated housing has first and second axial extremities. The fist axial extremity is open to the interior of the second housing, at least the first axial extremity and an axial portion of the second elongated housing are dimensioned and configured to extend with at least the first axial portion disposed within the first elongated housing. The first axial portion tapers axially from a larger to a smaller cross section at the first axial extremity. The apparatus also includes means for selectively preventing flow in the second elongated housing.

Abstract: An otherwise conventional recovery boiler for burning black liquor (e.g. with a consistency of between about 70-90%) requires less capital investment and takes up less space by constructing the economizers in a particular manner. At least first and second economizers are provided for preheating feed water utilizing flue gas from combustion of the black liquor. The economizers are positioned substantially adjacent each other and connected in such a way that flue gas leaving the first economizer passes substantially directly (i.e. without going through a conventional accessory passage) into the second economizer. The economizer inlets and outlets are substantially at the same level as the adjacent economizer outlets and inlets, or vertically spaced less than about one-third the length of the previous economizer. A boiler bank may be connected between the superheater section of the recovery boiler and the first economizer, and any number of economizers can be utilized.

Abstract: The present invention relates to a method for the combustion of waste liquids in connection with recovering of chemicals from the waste liquid, preferably black liquor from pulp production whereby the liquid (5A) is injected at a given level (4) into a furnace (1, 2, 3) in which the liquid (5A) initially is dried and the solid remainder thereafter is pyrolysed and finally burned and the chemicals are assembled on the bottom of the furnace while the exhaust gases (8) are going up through and out from the furnace (1, 2, 3) and whereby a part of the combustion air, so called primary air (11), is supplied at one or more levels (6) below said level (4) of liquid injection (5A) and another part of the combustion air, so called secondary air (12), is supplied at one or more levels (7) between said levels for liquid injection (4) and primary air supply (6) respectively, whereby the secondary air (12) is supplied to the furnace (1, 2, 3) in such a way that the gas is forced to rotate in a plane substantially perpendic

Abstract: A method of drying black liquor to a dry solids content of about 100% in which water is evaporated from the black liquor by direct heat exchange contact with hot smelt from a recovery furnace in which the dried black liquor is burned.

Abstract: A method and apparatus for introducing combustion air in the form of air jets into a furnace (2) of, for example, a soda recovery boiler. Combustion air is introduced through air ports (12), arranged substantially at the same level (10), in air jets (13) of at least two sizes. Air ports in the walls (4) of the furnace are dimensioned in different sizes such that their hydraulic diameters increase from the corners of the furnace towards the centers of the furnace walls, whereby the degree of penetration of the respective air jets flowing through the air ports increases. The penetration of the air jets in maintained constant at different loading conditions.

Abstract: In a combustion air supply system, particularly a secondary air supply system for a recovery furnace, the secondary air inlet ports are divided into two arrays in such a manner that the combustion air coming in through the inlet ports of the first array is directed in part to contact and in part to by-pass a central region in the outer surface of a carbonization layer. The combustion air coming in through the inlet ports of the second array is directed to by-pass the combustion air coming in through the inlet ports of the first array thereabove. The first and second arrays are located on the opposite walls of the combustion chamber, preferably on the front and rear walls. The recovery furnace further comprises a primary air supply zone for blowing combustion air onto the sides of the carbonization layer and a tertiary air supply zone above a waste liquor inlet.

Abstract: An apparatus for controlling operation of a recovery boiler for compensating a predetermined reference temperature of black liquor by a compensation value in accordance with a type of an injecting gun provided in the boiler, a compensation value set by the properties of the black liquor, a compensation value set by the temperature of charbed and a compensation value set by an air flow rate to the boiler representing the magnitude of boiler steam output or load to control the black liquor temperature supplied to the boiler.

Abstract: In a continuous pressurized process for the combustion, in the presence of steam and alkali, of solid fuels charged as aqueous slurries, the improvements comprising the elevation of inlet zone temperature in an entrained phase reactor by recirculating hot solid products to the zone, maintaining increased temperature and/or reduced steam partial pressure in the reactor and/or utilizing contaminated water from an associated fuels processing apparatus as a source of slurry and/or reactor temperature control water. An embodiment suitable for a coal-fired gas turbine locomotive is described and illustrated.

Abstract: A combined sulphur burning furnace and water-cooled boiler arrangement for producing a cooled, gaseous sulphur dioxide-air mixture in which the furnace is located below the boiler tubes arrangement in a vertical, cylindrical shell. The hot gases produced in the furnace exit axially into an upper chamber defined by the water-tube arrangement and pass through the cooling water-tube arrangement in radial outward flow to an outer chamber provided with cold-side by-pass control means and then exit the shell. The apparatus provides for savings in ducting, foundations, piping and the like; and permits more efficient sulphur burning and cooling.

Abstract: Apparatus and method is disclosed for monitoring black liquor recovery boilers to detect the presence of water leakage into the combustion chamber (furnace) of a black liquor recovery boiler, or extinguishing of flame at the black liquor spray nozzles, to release into the furnace at a relatively high rate of speed an absorption agent to collect the water in the furnace and thereby isolate the water from the smelt, and further to provide a medium from which the water may be evaporated to expedite cooling within the furnace without risk of a water/smelt explosive reaction. The apparatus includes propulsion devices for distributing the absorption agent over the furnace smelt, which propulsion devices are controlled by sensors respectively detecting boiler steam pressure, water pressure, and combustion flame. Manual actuation of the propulsion devices is also contemplated by the invention.

Abstract: A continuous process for the combustion of solid fuels under conditions such that flue gas is essentially free of particulates and oxides of sulfur and nitrogen. Fuel is charged as an aqueous slurry and additional water condensed from the flue gas may be recycled to the pressurized combustion zone. Combustion is promoted both by water vapor and alkali added with the fuel slurry, while the alkali serves also to neutralize and remove sulfur in completely oxidized, or sulfate, form. Heat of combustion raises the temperature of the reactants above the critical temperature of water, forming a hot fluid from which useful heat is transferred. Under the pressure of the system, heat recovery results in condensation of water, retaining and slurry product ash and providing recycle water, which helps to control reaction temperature as well as to promote the combustion.

Abstract: A recovery system for residual liquor from a pulp mill, utilizing a fluidized bed to burn the organic material in the residual liquor and generate heat which may be recovered. Heat preferably from the flue gases is used to dry residual liquor sprayed to pellets extracted from the bed, thereby to provide pellets coated with dried residual liquor. The so coated and dried pellets are then reinjected into the bed and the organic material in the dried residual liquor is burned to generate the heat recovered from the bed.If the residual liquor is from a kraft mill sulfur compounds are in the form of sulfate and must be reduced to sulfide and a reducing stage will also be provided either in the reducing zone in existing conventional kraft system (if capacity is available) or in a separate reducing zone and some of the pellets from the bed may be directed to the reducing zone together with some of the pellets coated with dried residual liquor.

Abstract: At start-up, a bed of pellets derived from pulp mill residual liquor is fluidized by feeding preheated air to the bed to initially raise the temperature of the bed to a temperature at which a particulate ligno-cellulosic auxiliary solid fuel may be completely consumed (800.degree.-850.degree. F.

Abstract: A material in slurry form is heat treated by being sprayed onto a fluidized bed wherein its combustible component is burnt to generate heat. Elutriated fines material is recycled to the bed to control the mean particle size distribution in the bed and in such a manner as to secure that the sprayed material contacts at least some of the recycled fines.

Abstract: A waste liquor recovery furnace includes a lower combustion chamber and an upper final combustion chamber, separated by a restricted gas passage. The furnace has a basically cylindrical configuration, being defined by a tube membrane shell, and the lower combustion chamber is formed by tubes from said shell being bent, doubly inwards, defining a discharge opening for the liquid combustion residue. A screen of tubes in the final combustion chamber is arranged to direct the gases towards the shell, being substantially solid in the center of the chamber, directly above the discharge opening.