Abstract: Heat exchanger for thermo boiler 1 with a tube bundle 6 using solid fuel in particles constituted from an inner furnace 7 and a double wall jacket connected from the tube bundle 6 characterized by the fact that space 14 over the inner furnace 7 and the tube bundle 6 is divided from a slab 13, that tubes 6 which cross said slab 13 in openings 15 are rigidly fixed to said slab 13, that at least a bar 10, 11 which can be controlled from outside crosses the slab 13 and the double wall jacket 20 on at least one side, that said bar/s 10, 11 bring/s at least two scraping plates 8 and 9, of which an at least intermediate one positioned on one side of said slab 13 and at least an other one from the opposite part of slab 13, of which at least one positioned at the end of tubes 6.

Abstract: Methods and systems for preparing a torrefied biomass fuel are disclosed. Moisture is initially extracted from relatively wet biomass fuel to produce a relatively dry biomass fuel. Remaining moisture is then extracted from the relatively dry biomass fuel in a final drying stage, using steam at a temperature of about 900° F. The resulting dried biomass fuel is conveyed downward using gravity and undergoes torrefaction, which produces torrefied biomass fuel and torrefaction gases. A gaseous mixture of steam and torrefaction gases is vented to a heat exchanger, where the gaseous mixture is heated by a flue gas, and the heated gaseous mixture is used to support the extraction of the remaining moisture in the final drying stage and to support the torrefaction of the dried biomass fuel. Embodiments disclosed herein efficiently use available energy resources to the benefit of manufacturers, consumers, and the environment.

Abstract: Methods and systems for preparing a torrefied biomass fuel are disclosed. Moisture is initially extracted from relatively wet biomass fuel to produce a relatively dry biomass fuel. Remaining moisture is then extracted from the relatively dry biomass fuel in a final drying stage, using steam at a temperature of about 900° F. The resulting dried biomass fuel is conveyed downward using gravity and undergoes torrefaction, which produces torrefied biomass fuel and torrefaction gases. A gaseous mixture of steam and torrefaction gases is vented to a heat exchanger, where the gaseous mixture is heated by a flue gas, and the heated gaseous mixture is used to support the extraction of the remaining moisture in the final drying stage and to support the torrefaction of the dried biomass fuel. Embodiments disclosed herein efficiently use available energy resources to the benefit of manufacturers, consumers, and the environment.

Abstract: A dual fuel boiler has a granular fuel burner and a fluid fuel burner. The fluid fuel burner is movable between a retracted stored position at a side of a combustion chamber-of the boiler and an extended operative position in which it extends out over a brazier of the granular fuel burner. Thus in the operative position substantially all of the flame and hot combustion gases generated by the fluid fuel burner in use are directed away from the brazier to prevent damage to the brazier.

Abstract: A fuel preprocess system for a coal combustion boiler is disclosed. The fuel preprocess system for a coal combustion boiler that dries biomass or refuse-derived fuel in accordance with the present invention can include: a dryer configured to dry the biomass or refuse-derived fuel by use of flue gas generated after combustion in the boiler; and a torrefier configured to devolatilize a fibrous component contained in the dried fuel from the fuel dried in the dryer by use of primary air that is heat-exchanged after the combustion in the boiler.

Abstract: A boiler (1) comprising at least: a furnace (2), in whose lower part the combustion used as the primary source of thermal energy of the boiler is configured to take place; devices (6) for supplying fuel into the furnace; devices (3, 7, 8, 26) for supplying combustion air into the furnace; one or more flue gas ducts (11); at least one chamber (17) accommodating at least one steam superheater (15) for recovering thermal energy. Said chamber is configured to allow a direct line of sight (16) between said superheater and said primary source, to enable the reception of thermal energy by means of thermal radiation. Said chamber is further configured to prevent the entry of said flue gases (19) to said superheater either totally or almost totally, to avoid the reception of thermal energy by convection.

Abstract: A heating system has a heating unit with a combustion chamber for burning wood pellets or other pelletized fuel. The heating unit is controlled by a process control module that automatically keeps all operating functions within predetermined limits for safe, efficient and easy operation. The unit also includes a combustion air distribution assembly with a stir shaft that rotates within the combustion chamber and introduces combustion air through orifices along the length of the shaft to enhance fuel combustion. A thermo cycle plumbing assembly serves as a safety feature by preventing overheating in the event of a power failure or pump failure. Also included in the unit is a removable insulated firebox burn chamber that provides a high temperature combustion atmosphere and a heat/particulate recovery module which provides maximum heating efficiency and reduces emissions, meeting EPA requirements and contributing to a cleaner environment.

Abstract: A method of introducing oxygen into a boiler system for combustion with a prepared fuel in a furnace combustion chamber comprises providing a plurality of swirl-inducing elements to the air stream delivery lines, and a plurality of oxygen delivery jets adjacent the intake region and substantially surrounding the air stream delivery lines; igniting the fuel gas to create a flame; and delivering a stream of oxygen through the jets tangentially to the flame envelope to substantially shape and stabilize a swirling flow field for the flame, the oxygen concentration in the flame envelope gradually increasing towards an outer periphery of the flame envelope. A boiler system for using the method can be a new system or a retrofit to an existing system. The method and system provide advantages in reduced environmental impact and increased efficiency while addressing the safety factors involved in introducing oxygen to boiler systems.

Abstract: A steam generator achieves an especially high efficiency when biomass is used as a fuel. The steam generator contains a first combustion chamber for generating a gaseous working medium by burning a first fuel and a second combustion chamber for burning a second fuel. The second combustion chamber is connected downstream of the first combustion chamber in flow direction of the working medium. Bituminous coal may be fed as the first fuel to the first combustion chamber and/or biomass, in particular straw, may be fed as the second fuel to the second combustion chamber. The working medium generated in the first combustion chamber during operation of the steam generator serves as combustion air in the second combustion chamber.

Abstract: A boiler comprises a shell for fluid to be treated and divided into first and second heat exhange zones by at least one baffle, the zones being in communication with one another beneath a lower end of the baffle. Exhaust gases from a combustion source are supplied to a plurality of heat exchange tubes extending through each zone in heat exchange relationship with the fluid in the shell and being arranged in passes sequentially connected to one another whereby the exhaust gases pass sequentially through the first and second zones. The fluid to be heated is fed to an upper region of the second zone such that the temperature of gases passing through at least some of the tubes in the second zone falls to below the dew points of combustion products therein, the tubes in which condensation occurs being orientated such that condensates flow therefrom for disposal.

Abstract: A system for monitoring combustion of coal in a boiler detects coal composition and heating value using a bulk material analyzer and determines an air/fuel mixture so that when the coal is burned oxygen is available throughout the boiler and the wall temperature of the boiler is maintained below the metallurgical limit and the surface temperature below the ash fusion temperature of the coal where slagging is not desired. The temperature and pressure of steam in the boiler, fuel and air flow rates and temperature and oxygen content of the stack gases are supplied to a boiler model. The boiler model predicts how varying the air supply rate affects sensible heat loss. Periodic measurements of unburned carbon in the ash produced by combustion of the coal are correlated with the operation of the boiler at the time that the ash was produced to provide a basis for estimating unburned coal loss.

Abstract: A method for controlling the combustion and reduction processes in a black liquor (B.L.) boiler of a paper pulp plant by influencing the feeding of black liquor to the B.L. recovery boiler by means of a B.L. gun. Characteristic of the method is that the average thickness of the layer of the B.L. flow, immediately after the black liquor has left the B.L. gun, is controlled to have a desired magnitude. The thickness of the B.L. layer is obtained in the form of an indirect measure which is defined as the droplet index (=DIX) and is constituted by a relationship between the viscosity, the density and the feed rate of the black liquor and by at least the shape and the opening area, of the B.L. gun.

Abstract: A method for combusting slagging coal in a furnace comprising a firebox and at least one injection nozzle having a bore for a primary airstream and an annular passage for a secondary airstream, the nozzle communicating with the firebox, which method comprises (a) injecting a primary airstream containing a pulverized coal and injecting a secondary airstream through the injection nozzle into the flame zone of the furnace firebox, the combined primary and secondary airstream composing the total air for combustion and combusting the coal to yield a flame of combustion, and (b) injecting a sufficient amount of oxygen into the primary airstream such that an oxygen enriched primary airstream emanates from the injection nozzle and the oxygen concentration of the total air for combustion is about 22 to 27 volume percent, whereby the amount of slag deposition is reduced.

Abstract: Wood-waste products, such as wood shavings, wood chips and sawdust, are burned in an apparatus having a waste burner comprising an elongated cylinder in which fuel and air are mixed and ignited before entering an enlarged combustion chamber. The waste burner is characterized by an elongated cylinder having a length substantially larger than its diameter so that the fuel can be heated to a temperature sufficient to pyrolyze volatiles and initiate combustion in the cylinder. A wood-waste burner apparatus is also provided and comprises the waste burner of the invention and a combustion chamber for receiving unburned fuel and combustion products emanating from the burner. A process for burning wood-waste products is also provided. The invention is especially well suited for retrofitting packaged boilers to accommodate wood-waste fuels.

Abstract: A fluidized bed furnace and boiler for the combustion of flyash with a moisture content of 45% by weight. The flyash is produced as a by-product of a coal gasification process and transported in water to a slime dam. From the slime dam a slurry of flyash and water is initially thickened in a gravity thickener (1) (FIG. 1) and then converted to filter cake in a tubular filter press (4). The filter cake is fed through pressurized hoppers (8) and chutes to the base of the boiler (10) and is distributed across the floor through chutes in the side walls and through chutes surrounded by a tubular array of water tubes and extending into the boiler furnace chamber terminating approximately one quarter of the furnace width from the side walls. A fluidized bed with a depth of about 3 meters is formed by discharging air heated in an associated air heater through nozzles in the floor of the furnace chamber to effect combustion.

Abstract: A water gas furnace comprising an outer container to provide a housing in which coke is placed into its lower part. A water container is placed within the housing. The coke is ignited and heats the water in the container converting it into steam. The steam is ejected into the coke, which together with air, produces water gas. Preferably, pumice stones are placed above the coke. The water gas is accepted into the pores of the pumice stones, where the heated pumice stones ignite the water gas, producing heat. The heat is extracted by a heat exchanger provided about the housing.

Abstract: A method for generating steam by a high pressure, high intensity, or high heat release method of combustion in an elongated combustion zone having upstream and downstream ends and an intermediate location and utilizing a normally-solid fuel which produces non-combustible solid residues in which the fuel is introduced axially and a volume of air, at least equal to the stoichiometric amount, is introduced as an annular, rotating stream to produce a rotating vortex of fuel and air, such introduction and flow through the combustion zone being carried out in a manner to collapse the vortex and create plug flow at the intermediate location, burning the fuel and air to produce flue gas at a heat release rate of at least 7 MM Btu/hr, abruptly terminating combustion by the introduction of water, vaporizing the water to produce a mixture of flue gas and steam, and separating solid residues therefrom.

Abstract: A method is described for burning pulverized high ash coal in a furnace firebox and reducing ash fines which comprises(a) injecting a primary airstream containing a pulverized coal which is at least 7 wt % ash and a secondary airstream into the flame zone of a furnace firebox and combusting the coal to yield a flame of combustion, and(b) injecting a sufficient amount of oxygen into the flame zone via the secondary airstream such that the oxygen concentration of the combined primary and secondary airstreams is between 21 to about 28 vol %.In a preferred embodiment, the oxygen enrichment addition is proportioned between the primary and the secondary air streams.

Abstract: A system for generating, storing and releasing heat comprises a tank surrounding a reservoir for holding a heat transfer fluid, heat releasing means in fluid communication with the reservoir for controllably releasing heat from the fluid to an object or space to be heated, and means for regulating flow of the fluid between the reservoir and the heat releasing means. A heat conductive fire chamber is disposed within and substantially surrounded by the reservoir, the system also comprising an air supply means for carrying combustion air to the fire chamber, and a heat conductive exhaust means for carrying hot exhaust gases through the reservoir. Access passageways are provided for fuel insertion and ash removal. Boiler tubes supporting the fuel as well as collecting heat from the fire chamber communicate with fluid in the reservoir. Shaker bars interspersed between the boiler tubes supporting the fuel may be actuated to agitate and more completely combust the fuel.

Abstract: A plant for the incineration of waste, primarily from retreading shops, with the simultaneous use of the energy content of said waste for steam regeneration to operation and heating. The rubber waste is dosed in an amount dependent on the heat need of the shop with a screw to a grinder where it is ground down into small particles which, mixed with air, are blown into a furnace mounted onto the bottom of a steam boiler. By means of the blowing into the furnace as well as the blowing of flue gas at high temperature in the boiler taking place tangentially, a long period of stay for the burning particles is obtained, thus obtaining a total incineration. The outgoing flue gas is purified prior to release in the usual manner. The furnace is provided with an oil burner, which, in the event of a low energy need in the plant, has sole responsibility for steam regeneration over the oil system and control equipment.

Abstract: A steam or hot water generator, operating by solid fuels having high contents in volatile materials, provides that the column of fuel bears on an inwardly inclined grate. A fraction of the carbureting air passes through the grate and fuel, carrying along the volatile products. Another fraction of air, not passing through the grate and accordingly also not through the fuel, but which is however heated by travelling under the grate, joins with the fraction rich in volatile products which is still unburnt, bringing the latter to combustion.

Abstract: Methods and apparatus for burning fuel from a supply of solid fuel positioned at one side of a grating light a layer of the solid fuel at the grating to discharge combustible gas. Such discharged gas is drawn through the grating to a side of the grating opposite the mentioned one side and such drawn gas is burned at the other side of the grating. Attainable temperature of said grating, acting as a primary grating, is increased by providing a secondary grating spaced from such primary grating and located between that primary grating and a fire chamber.The methods and apparatus of the subject invention enable particulate, pelletized and other solid fuels, as well as combustible refuse and garbage, to be burned at an efficiency and convenience similar to the combustion of heating oil, and yet provide heat at a fraction of the cost of oil and gas heating methods.

Abstract: A domestic combustion appliance 1 has a body 2 having a distributor plate 14 for supporting a shallow fluidized bed 32. A primary boiler 34 forms part of a rear bounding wall for the fluidized bed 32, and a secondary boiler 50 is located downstream providing flue passages for exhaust gases. A window 10 is provided in the front wall 8 to give a visual effect for volatiles burning, in use, above the bed 32.

Abstract: The invention reads on a heating boiler for solid fuel, comprising a combustion volume with fuel feeding aperture, air entry apertures and chimney flue, and a water volume, the latter bordering on said combustion volume by mediation of convection plates. As taught by the invention, the boiler comprises air guiding elements for guiding the combustion air substantially across the combustion volume so that the point of air entry moves with time from one point in the combustion volume across the combustion volume for burning the fuel in the combustion volume zonally. The air guiding elements may consist of air entry apertures provided in the wall, disposed in a row across the combustion volume, and they may incorporate closing members for consecutively opening and closing the apertures e.g. with the aid of a governing apparatus from one margin to the opposite margin of the combustion volume.

Abstract: Sulfur is readily and efficiently removed from solid fuel in a boiler installation which comprises a hearth for burning and thereby gasifying the solid fuel, the hearth including a grid supporting a fluidized bed of the solid fuel spread thereover, and a tubular boiler body superimposed on, and integral with, the hearth, the boiler body including a lower portion receiving the gasified fuel from the hearth, an upper portion, a common transverse wall dividing the tubular boiler body into the lower and upper portions, and a burner extending into the upper boiler body portion near the dividing transverse wall and receiving a supply of secondary combustion air. A conduit connects the lower boiler body portion to the burner for feeding the gasified fuel therefrom to the burner, and dust removing and desulfurization cyclones in the conduit remove dust and sulfur from the gasified fuel.

Abstract: An improved multi-fueled hot water or steam boiler comprising a plurality of compartments, one compartment for the combustion of a solid fuel, such as wood or coal, and the other for the combustion of a liquid fuel and separated from each other and the exterior of the boiler by water-conducting walls; a water supply tank positioned above one of the compartments and connected to the water-conductive walls; and a plurality of horizontal fire tubes passing through the water supply tank and connecting one compartment to an exhaust flue. The compartment not positioned below the water supply tank has a water-conductive ceiling slanted upwardly toward and connected to the water supply tank. One compartment has an adjustable air-flow secondary damper in addition to a primary air damper. The water-conductive walls, fire tubes, adjustable secondary damper, and upwardly slanting water-conductive ceiling reduce boiler heat losses and improve boiler efficiency.

Abstract: A furnace for alternatively burning solid or liquid fuels is disclosed. The furnace includes an oil burner and a solid fuel burner as well as a combustion chamber for the burning fuel. The hot combustion gases can be introduced through one of two sets of chimney gas flues, depending upon the fuel being burned. A tiltable flap at the inlet of the chimney gas flues controls which set of flues the gas passes through. At the outlet of the flues, a reversing chamber reverses the direction of the gases and directs them to a flue gas pipe for removing the combustion gases from the furnace. The position of the tiltable flap is controlled by a control means responsive to the sensed temperature of the gas leaving the furnace. The chimney gas flues define a heat exchanger and may be formed from flat plates or round ducts.

Abstract: The vapor generator employs a convection heating surface in the gas flue upstream of the superheater heating surface in the exhaust gas flow. The burners for the different fuels are disposed in a common horizontal plane in the combustion chamber.In one embodiment, one water separator is disposed between the evaporator and convection heating surfaces while a second water separator is disposed between the convection and superheater heating surfaces.In another embodiment, one separator only is used with a change-over circuit means to connect the separator either between the evaporator and convection heating surfaces or between the convection and superheater heating surfaces.

Abstract: A heating boiler comprises separate furnaces for oil and solid fuel. The oil combustion chamber can be connected directly to flues in contact with water via an afterburning chamber (11) common to the two furnaces. The connection (22) between the oil-combustion chamber (8) and the afterburner chamber can be shut off by a damper (25). Instead a connection is opened between the oil combustion chamber and the furnace (9) for solid fuel via an ash compartment and a grate (20) under the furnace for solid fuel. Through the arrangement with the damper (25) a number of possible variations can be obtained depending on the actual heat requirements.

Abstract: A boiler provided with a burner chamber for a burner firing system and a combustion chamber for a solid fuel firing system, both chambers being arranged horizontally side by side in a common boiler water space enclosed by a horizontal outer boiler body. The combustion chamber has an approximately elliptical cross-section with vertical major diameter and the burner chamber has a round cross-section, the longitudinal center lines of both chambers being substantially at the same level. Both chambers are connected at their front ends with two separate horizontal ancillary heating passages extending axially parallel above the chambers within the boiler water space and having rectangular cross-sections with horizontal major cross-sectional dimensions and with internal comb-like ribbings. The outer boiler body is made of a metal sheet shaped in one piece by rolling into a hollow body of non-circular roundish cross-section.

Abstract: A double-fired heating boiler includes first and second combustion chambers positioned within a common boiler water chamber and adapted to be fired respectively by gas or oil and by solid fuel. A collector for the combustion gases produced by the burning of the fluid and solid fuel is provided. Separate exhaust conduit systems having ancillary heat exchange surfaces are connected to the respective combustion chambers and to the collector.

Abstract: A multi-fuel boiler is provided in which coal is burned in combination with oil or gas in such manner that the particulate emission from the coal, normally relatively high, is reduced to a level comparable to oil. In one example, coal of a quality that would normally burn with a Bacharach smoke spot test number of 6 can be burned with a test number below 2.This is accomplished by utilization of a horizontal oil or gas flame directed across the flue gas exit of the combustion chamber in opposition to the flow of coil combustion gases to change the normal flow pattern of the combustion gases. This creates turbulence, which provides additional combustion time at combustion temperatures in the presence of excess air.