Abstract: The present disclosure relates generally to novel biomass pyrolysis processes and systems that decrease entrainment of char and other contaminants with the pyrolysis vapors as a direct consequence of the biomass feedstock comprising particles that are larger than a defined minimum diameter. The biomass feedstock may optionally be compressed to form feedstock pellets that are larger than a defined minimum diameter.

Abstract: The invention relates to a multi-level furnace for thermal treatment of the material flow which has at least two process chambers arranged one above another, each providing at least two level floors, and is equipped with one or more transfer devices for transferring the treated material flow from an upper process chamber to a lower process chamber. In order to separate the two process chambers in terms of gas flow, the transfer device has means for forming a material column in the transition region between the upper and the lower process spaces, wherein said means for forming a material column comprise at least one conveying unit or at least one chute, and the at least one conveying unit or at least one chute also forms a material removal device for the upper process chamber and/or a material input device for the lower process chamber.

Abstract: A device for drying and torrefaction of at least one carbon-containing material flow in a multiple-hearth furnace includes a drying zone, a torrefaction zone, a heat exchanger for heating the drying gas flow, the discharge point of the drying zone being connected via the heat exchanger to the infeed point of the drying zone; and a combustion assembly, wherein the discharge point of the torrefaction zone is connected via the combustion assembly and the heat exchanger to the infeed point of the torrefaction zone, wherein a torrefaction gas flow discharged via the discharge point of the torrefaction zone is combusted in the combustion assembly and the resulting exhaust gas is used in the heat exchanger to heat the drying gas flow and is fed to the torrefaction zone, wherein the drying zone and the torrefaction zone comprise two separate gas circulations.

Abstract: A biomass-mixed-firing pulverized coal fired boiler includes: a furnace for burning biomass fuel together with pulverized coal in a mixed state; a pulverized coal burner for supplying the pulverized coal into the furnace; a biomass burner for supplying the biomass fuel into the furnace; a biomass mill for milling the biomass fuel to be supplied to the biomass burner; a dry clinker processing unit provided below the furnace and including a clinker conveyor for carrying ashes discharged from the furnace at a furnace bottom; and a combustion-air supply unit for supplying combustion air toward the ashes discharged at the furnace bottom on the clinker conveyor, thereby to burn an unburned component of the biomass fuel contained in the ashes discharged at the furnace bottom on the clinker conveyor.

Abstract: A multiple hearth furnace including a rabble arm with a tubular structure and a solid plug body. The latter is received in a socket arranged in an arm fixing node. It has an axial through boring and cooling fluid supply and return channels arranged around this through boring. A clamping bolt is rotatably fitted in the through boring. It has a bolt head, which can be brought by rotation into and out of hooking engagement with an abutment surface on the arm fixing node. A threaded end of the clamping bolt sticks out of the through boring at the rear end of the plug body. A threaded sleeve, which is screwed onto this threaded end, bears on an abutment surface at the rear end of the plug body for exerting a clamping force onto the clamping bolt.

Abstract: The present invention provides a burner which uses solid fuels, especially waste plastic fuels. Burner size is minimized by having multiple combustion chambers concentrically located around a rotating screw conveyor. Heat efficiency is improved by having air passages disposed around the combustion chambers, thus preheating air for the combustion prior to its delivery to the combustion chambers, while simultaneously thermally insulating the combustion chambers against the environment. Waste plastic is transported from a fuel hopper to the combustion chambers by a rotating screw conveyor having the spiraling auger blades. Speed of screw conveyor rotation controls the consumption of waste plastic and, thus, the amount of thermal energy generated in the burner.

Abstract: A method for improving a slag quality of slag in a grate firing system. The method includes providing slag in a grate firing system including a combustion chamber disposed above a combustion bed. The combustion bed has a plurality of fixed-bed burnout zones in series on a combustion grate. The fixed-bed burnout zones include a first series of fixed-bed burnout zones and a second fixed bed burn-out zone disposed downstream of the first series. The first series of fixed-bed burnout zones is traversed with a flow of oxygen-containing gas. A portion of the combustion bed associated with the second fixed bed burn-out zone is traversed with a flow of a hot combustion gas from the combustion chamber.

Abstract: The inventive multi-level furnace comprises a furnace wall delimiting a cylindrical space having a vertical axis, a plurality of beds defining the levels inside said cylindrical space and at least one scraping arm which is provided with a wall scraper and associated with the bed in such a way that it is rotatable about the vertical axis of the furnace. During scraping arm rotation, said wall scraper defines a scraped area on the internal surface of the furnace wall which comprises a plurality of wall cavities forming a row of access openings in the scraped area, thereby making it possible to avoid the formation of a hardened crust adhered to the internal surface of the furnace wall and to develop braking shocks in the scraping arm.

Abstract: A method of operating a multiple hearth furnace with a plurality of vertically aligned hearth floors includes feeding a first material onto the uppermost hearth floor and moving it over the hearth floor before it falls through a drop hole onto the next lower hearth floor. The first material is processed in this way from hearth floor to hearth floor to the lowermost hearth floor. A second material is fed onto one of the hearth floors to be mixed into the first material. This second material is moved separately from the first material in a separate annular zone of the hearth floor onto which it is fed before it is mixed into the first material, providing an efficient thermal preconditioning of the second material prior to mixing it with the first material without requiring any supplemental equipment.

Abstract: A rabble arm for a furnace, as e.g. a multiple hearth furnace, comprises an elongated metallic support core (10), at least one rabble tooth having a rabble portion and a fixing portion and fixing means co-operating with the fixing portion for fixing the rabble tooth (14) to the elongated metallic support core. The fixing portion (48) includes a through hole through (50) which said elongated metallic support core axially passes; and the fixing means co-operates with the fixing portion (48) around the through hole for fixing said rabble tooth (14) to said elongated metallic support core (10).

Abstract: A method of operating multiple hearth furnace (10) with a plurality of vertically aligned hearth floors (361, 362, 363, 364, 365), comprises in particular following steps. A first material is fed onto the uppermost hearth floor and moved over this uppermost hearth floor (361) before it falls through a drop hole (40) onto the next lower hearth floor. This first material is processed in this way from hearth floor to hearth floor down to the lowermost hearth floor (366). A second material is fed onto one of the hearth floors to be mixed into the first material. This second material (64) is moved separately from the first material in a separate annular zone (68) of the hearth floor onto which it is fed before it is mixed into the first material. The method allows to provide an efficient thermal preconditioning of the second material prior to mixing it into the first material without requiring any supplementary equipment therefore.

Abstract: A furnace has a dual structure for carbonizing material. The furnace has a group of inner chambers and an outer chamber. Each of the inner chambers has a lid which can open and close to input the material for carbonizing. The outer chamber moves so that the group of inner chambers is housed in the outer chamber. Due to this, a combustion space is formed between the group of inner chambers and the outer chamber so as to heat each of the inner chambers to dry the material by distillation.

Abstract: A reactor for gasifying and/or melting feed materials, the reactor including a charging section with a feed opening, through which the feed materials are charged to the reactor from above and a pyrolysis section which has an expanded cross section and is located below the charging section so that a discharge cone of the feed material can form. Gas supply devices, open into the pyrolysis section substantially at a level of the expanded cross section and through which hot gases can be fed to the discharge cone. A melting and superheating section is located below the pyrolysis section and has a narrowing cross section. Upper injection devices are arranged so that an energy-rich medium is supplyable to the melting and superheating section immediately below a level of the narrowing section. A reduction section is located below the melting and superheating section. The reduction section has gas exhaust devices through which excess gases are exhausted.

Abstract: System for drying a damp biofuel, includes a boiler (1) for combustion of the fuel. Further, the system includes a first heat drying chamber (2), a drying gas flow (3) heated by the thermal energy of the combustion gases from the boiler and/or by steam, the gas flow being passed into the first heat drying chamber, and a fuel supply (4) for passing the fuel into the first heat drying chamber. The system includes a second heat drying chamber (5), an intermediate heating unit (6) for heating the drying gas flow before the second heat drying chamber, an intermediate supply (7) for passing the fuel from the first heat drying chamber into the second heat drying chamber, a boiler supply (8) for passing the fuel from the final heat drying chamber into the boiler and an outlet (9) for passing the flow of drying gas from the final heat drying chamber into the boiler.

Abstract: The present invention provides an incinerator for removing toxic substances contained in a flue gas. That is, there is here disclosed an incinerator for removing toxic substances in which a removal section for removing the toxic substances generated from a burning section is connected to the burning section for burning incineration substances, and an air flow of from the burning section to the removal section is prepared by a suction type negative pressure means or by an air duct type negative pressure means, so that a negative pressure condition is always maintained in the burning section.

Abstract: A multiple hearth furnace having a drying zone, a combustion zone and a cooling zone includes a recirculation loop that recycles exhaust gas from the drying zone to the cooling zone. In some embodiments, a first control loop including a temperature measurement device that measures temperature in the combustion zone controls fan speed of a recirculation fan that drives the recirculation loop. A second control loop monitors recirculation fan temperature and overrides the first control loop if the recirculation fan temperature exceeds a predetermined maximum. A third control loop controls air flow into the furnace.

Abstract: A waste incinerator including separate burning-, blower-, chimney- and ash-receiving chambers. A suction-discharge port is provided in a wall between the burning chamber and the chimney chamber for discharging gases from the burning chamber through a chimney to the atmosphere. The chimney extends from the chimney chamber for discharging gases to the atmosphere. The chimney receives an air feed pipe from the blower and an ignition sleeve extends into the chimney for burning unconsumed waste gas. A vibrator vibrates an ash receiver in the ash receiving chamber, and a drying chamber may be provided for drying high moisture garbage by combustion gases from the burning chamber.

Abstract: An improved apparatus and method for efficiently processing material, e.g. incinerating waste material, particularly dewatered waste water sludge, in a multiple hearth furnace by injecting high velocity jets of oxygen into the heating or drying zone of the furnace to augment turbulent gas-phase mixing, to aid in the burnout of carbon monoxide and hydrocarbons in the gas phase to achieve lower emissions, to increase convection over the drying sludge to increase its drying rate, and to ignite the drying sludge to further increase its drying rate. The apparatus and method provides an increase in sludge throughput and a reduction in carbon monoxide, nitrogen oxides and hydrocarbon emissions.

Abstract: An apparatus and process for removing unburned carbon in fly ash. The apparatus includes a stainless steel heating chamber heated in a range from 800 to 1200 degrees F. The fly ash is introduced at one end of the heating chamber and moved slowly to an opposite end by a screw auger. The auger mixes the fly ash with oxygen. The oxygen is introduced at spaced apart heating areas along the length of the heating chamber. The oxygen accelerates the heating and burning of the unwanted carbon in the fly ash. The amount of oxygen introduced into the heating chamber is under computer control to regulate the temperature in the heating chamber and the heating of the fly ash. In the burning of the unwanted carbon in the fly ash, the carbon acts as a fuel in combination with the oxygen for heating the fly ash and removing the carbon from the fly ash. The heating chamber is also used to preheat untreated fly ash received through a preheating chamber before it is introduced into the heating chamber.

Abstract: An incineration furnace for disposal of waste in which substantially complete burning of waste materials is obtained. A stirring member is rotatably supported in the interior of an incinerator housing, making up the main incineration furnace body. Air for accelerating burning of the waste material is forcibly fed from a blower through the stirring member. The stirring member is rotated and driven through the inside of the housing by a motor. Waste is agitated and mixed between movable tubes provided on the stirring member, and by first and second fixed blades disposed in the incinerator housing, thereby facilitating burning and incineration of the waste material.

Abstract: A process of drying moist or wet carbon particles in a series of tubular drying sections by electrical resistance heating where the current is introduced into the uppermost column of carbon particles through a graphite block positioned at the center of the top of the said column by attachment to a steel plate that includes a flat or a V-shaped shelf and that is provided with openings to allow the moisture to escape in the form of steam and wherein the dried or partially dried carbon may be fed into a second or into a sequential plurality of similar sections provided with similar graphite blocks similarly positioned.

Abstract: An apparatus for improving mass transfer in a multiple hearth furnace has a plurality of risers adjacent the furnace center shaft which are in fluid communication with a source of treatment fluid. The risers have radially extending branch pipes, each pipe having a plurality of downcomers corresponding to the rabbles on an adjacent rabble arm. The downcomers have outlets or nozzles at their distal ends and they are preferably located adjacent a rear face of the rabble, near a trailing edge. In operation, as the rabbles plough over the material on the furnace hearth, the downcomers inject a treatment fluid, such as steam or reducing gas, into the material at the point of stirring. This ensures full exposure of the material to the treatment fluid. A second embodiment places the outlets beneath the top surface of the material to be treated. A method for mass transfer on a rotary hearth furnace is also disclosed.

Abstract: An automatic firebox provided with a fuel hopper that delivers fuel through a pivoting funnel to a grate burning area. The grate burning area is provided with at least one pivoting fuel grate which operates automatically in sequence with the fuel feed and hopper so as to provide automatic stoking. An automatic control operated by temperature and/or time is disclosed.

Abstract: This invention is an apparatus for drying and burning high-hydrous combustible solids comprising: a hopper for containing high-hydrous combustible solids; a drier for drying said high-hydrous combustible solids when transported from said hopper to said drier 1; a combustion chamber for receiving and burning dried solid from a transportation tube; and a means to lead the waste gas from said combustion chamber to said drier to be used as drying gas. High-hydrous combustible solids are transported to furnace the combustion chamber immediately after being dried in the drier, and the waste gas from the combustion chamber is used as drying gas in the drier.

Abstract: A distillation type incinerator generates gas containing much combustible gas owing to restricted air introduction at feeding the combustible matters thereto and minimum necessary supply of air for combustion and dry distillation, and generates residue which contains less unburned matters and can be taken out in lumps, so as to reduce the amount of waste and facilitate the recycle of useful metals.

Abstract: A device for the thermal treatment of organic substances and of inorganic substances contaminated with organic substances which makes a high throughput possible. The reactor contains several bottoms provided with perforations with ceramic ball sections which can be moved separately.

Abstract: An apparatus and process for the incineration of sewage sludge in a concurrent-flow multiple hearth furnace-incinerator which complies with the fundamental thermodynamic conditions required to establish a sustained and stable combustion condition. The sewage sludge is incinerated to a truly inert and odorless ash, while yielding off-gas which has been burned free of all malodorous and condensable volatiles from which trouble-free steam and in-house electric power can be commercially produced and an excess sold to the local utility company.

Abstract: A melting disposal method of sludge. The method of the invention having the steps of collecting a plurality of cakes of dehydrated sludge generated at a plurality of sewage disposal plants at one melting disposal plant; incinerating or drying a substantially fixed amount or proportion of the dehydrated sludge cakes; mixing the resultant substance; and heat-melting the resultant mixture with addition of basicity conditioning agent.

Abstract: A vertical incinerator for burning general refuses and industrial wastes which comprises a plurality of sets of grates disposed at different levels within a furnace to divide the furnace into a plurality of combustion chambers in such a manner that the refuse charged into a top portion of the furnace is burnt as it is successively allowed to move downward to become ashes which are withdrawal from the bottom of the furnace.

Abstract: An improved method for controlling combustion zone temperature in a furnace independent of flue gas oxygen content is disclosed. The method comprises supplying a carrier gas containing a fine mist of liquid water droplets to the furnace combustion zone to control the maximum temperature within the combustion zone. The invention is applicable to both multiple hearth furnaces and fluidized bed furnaces, protecting the refractory furnace lining from damage.

Abstract: An apparatus arrangement in a system for circulating an inert fluid medium in a substantially closed and inert atmosphere during the grinding of wet gob to prevent spontaneous combustion and the initiation of fire from sparks created during grinding of moisture bearing waste material. The apparatus combines with a grinding mill a fluid circulating circuit with the grinding mill to separate ground particulate gob from the circulating fluid medium, and a second fluid circulating circuit in association with a boiler to burn the ground gob material for creating an oxygen deficient atmosphere in the fluid circulating circuit.

Abstract: This invention encompasses a process for the utilization of dried powdered waste as a fuel, in particular, dried powdered aqueous waste. The object of the invention is to eliminate the use of conventional auxiliary fuel to aid in thermal oxidation of waste materials containing a high percentage of water in relation to solids, thus improving the total efficiency of the process. The problems associated with handling the waste products are solved along with the expense of using conventional auxiliary fuels such as gas and fuel oils.

Abstract: Stalks of crop material, especially straw, are incinerated by comminuting them to pieces having a length of substantially 8 to 10 cm, pneumatically transporting the stalks to a separator in which the air is separated from the stalks and the stalks are then compacted and advanced in a rising bed into a furnace. Within the furnace, a low temperature distillation is initially effected and combustion is promoted along the free surface of the bed, in part sustained by the gases produced by the distillation. Ash as it is formed on the surface is entrained away with the hot gases. The ash is separated from the hot gases and advantageously collected in a water basin while the hot gases can be used for agricultural drying purposes and the ash for fertilizer.

Abstract: A combustion heater for oil shale heats particles of spent oil shale containing unburned char by burning the char. A delayed fall is produced by flowing the shale particles down through a stack of downwardly sloped overlapping baffles alternately extending from opposite sides of a vertical column. The delayed fall and flow reversal occurring in passing from each baffle to the next increase the residence time and increase the contact of the oil shale particles with combustion supporting gas flowed across the column to heat the shale to about 650.degree.-700.degree. C. for use as a process heat source.

Abstract: The present invention is directed to a biomass gasifier combustor which operates by gasification and combustion of the biomass to produce a clean effluent gas which can be used directly for grain drying or other applications where thermal energy is required. The biomass gasifier combustor burns crop residue clean enough so that the combustion gases can be used directly for grain drying without the need for a heat exchanger to isolate the combustion gases from the drying air. The biomass gasifier combustor includes a screw feeder tube having a screw feeder disposed therein. The screw feeder forces the biomass into a first combustion chamber. Primary combustion of the biomass produces a first combustion gas. A venturi gas pump creates a negative pressure region in the gasifier, drawing the first combustion gas into a second combustion chamber. An air passage is provided having a cross sectional area which increases the resistance to the flow of the first combustion gas into the second gas combustion chamber.

Abstract: A multiple hearth furnace chamber where each arched or conical hearth is independently supported by the outer metal shell. An expansion joint below each hearth allows for vertical movement of the interior refractory wall panels without significant vertical movement of the hearths. The expansion joint comprises an insulating refractory material which absorbs the expansion of the inner refractory (firebrick) wall panels without significant permanent deformation.

Abstract: A new and improved incinerator steam generation system subjecting to combustion debris such as municipal waste, utilizing the heat derived therefrom to produce steam for steam boiler, electrical generating facilities, heating facility for industrial or commercial plants, and so forth. This is provided with a series of boilers and controls, both manually adjustable and also automatic, whereby the possibility of fire dangers are minimized, created temperature ranges of boiler gases are constrained to desirable limits, dump stack facilities are automatically controlled as to particular effectiveness for differing types of operating conditions, and where safety features are incorporated to shut down gas flow through the boiler during periods of boiler-water deficiency, excess steam generation relative to demand, and other conditions. Within the furnace area proper the pressure conditions are predetermined and are controlled during operation for desired efficiency, vapor removal, and materials' combustion.

Abstract: An improved biomass gasifier combustor system including a furnace, a screw feeder system for feeding a biomass fuel to the furnace and a venturi eductor system adapted for drawing a gaseous combustion product from a combustion chamber of the furnace is disclosed. The furnace enclosure forms a principal chamber in which a housing containing a secondary air chamber is disposed so as to form a partition in the principal chamber which divides the principal chamber into two regions, one of which regions is a gasification chamber and the other of which is a gas combustion chamber.

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 after-burner or combustion hearths to within certain prescribed limits by splitting the feed sludge between the first two upper waste material handling hearths.

Abstract: The present invention relates to a method and apparatus for controlling the operation of a multiple hearth furnace system for efficiently incinerating combustible materials, such as sludge in which the air of combustion is essentially all introduced at the bottom of the furnace to incinerate solid materials. This control involves the following essential steps:scanning the temperature of two or more combustion hearths to determine which is the hottest hearth;controlling the temperature of the thus-determined hottest hearth at a predetermined temperature set point value;controlling the oxygen content of the system exhaust gas at least as high as the predetermined set point value; andmaintaining the system exhaust temperature at least as high as the predetermined set point value.

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: A rotary hearth pyrolyzer is described as having a conically tapered roll for uniformly spreading waste material that is charged onto the hearth for pyrolyzation. The taper of the spreader roll is such that the linear speed at any point measured longitudinally of the roll corresponds to the speed of the rotary hearth at a point on the hearth opposite the point on the spreader roll. An angularly disposed scraper blade is positioned slightly downstream of the spreader roll, relative to the movement of the rotary hearth, and has a pair of marginal edges, one of which engages the spreader roll to remove waste material sticking thereto and the other of which edges terminates in spaced relation from the hearth to evenly spread or distribute waste material onto the hearth.

Abstract: Freshly harvested agricultural materials having a moisture content no greater than 45% by weight are burned in a furnace in which the housing thereof is divided into preburning and afterburning spaces by a baffle wall. The preburning space contains a horizontally arranged first grating adjacent the baffle wall and a second grating adjacent the first and inclined upwardly therefrom and juxtaposed with an inlet in the housing for the introduction at a constant rate of the materials onto the inclined grating, the upper portion of which is fed by a first portion of primary air for the removal of moisture from the materials, while a lower portion of the inclined grating is fed with a second portion of primary air for the air-deficient burning of the dried materials and the production of combustible gases.

Abstract: A multiple hearth furnace feed distributor including a conical table feeder attached to the center shaft of the furnace for rotation therewith, together with a stationary convolute plow fixed above the conical table feeder.

Abstract: A method and apparatus for the consumption of relatively mass amounts of refuse in which a plurality of refuse burning grates are spaced one above the other. The refuse is supplied to and deposited selectively on selected ones or all of the grates while the grates are rotating so as to substantially evenly distribute the refuse thereon. The refuse is ignited to cause the same to burn and be consumed thereby becoming reduced in size such that the smaller sized refuse is enabled to fall through the grates producing a continual cleaning of the grates.

Abstract: A waste material treatment furnace includes a furnace chamber having an interior surface formed by a flexible sheet of an insulating fabric to minimize heat-up and cool-down time and to facilitate interior surface repair. The treatment furnace additionally includes an exhaust gas treatment facility for neutralizing and/or removing undesirable elements from an exhaust gas stream. The treatment facility includes a chamber having inlet and outlet openings, a conduit therebetween defined by wall members permeable to the passage of exhaust gas therethrough. A supply of a selected reactive material is provided in a compartment formed about the periphery of the permeable wall members, and means are provided to move the exhaust gas from within the conduit through the permeable wall members thereof into the selected reactive material within the compartment.

Abstract: The invention relates to the method and equipment for treatment of fuel for fluidized bed combustion, which includes drying, classification and crushing of the fuel. The method for treatment of fuel comprises mixing the fuel with hot ash removed from the fluidized bed combustor and drying said mixture in a fluidized bed dryer in which the velocity of the fluidization fluid equals or is lower than the minimum fluidization velocity of particles in the fluidized bed combustor. The equipment for treatment of fuel comprises a bunker, crusher and dryer, comprising a fluidized bed dryer provided with appropriate piping for interconnection of the fluidized bed dryer, fluidized bed combustor, fuel bunker and crusher.

Abstract: A process is disclosed in which any off-gas generated in a wastewater treatment plant, which off-gas has a low calorific (or BTU) value about one-tenth of that of natural gas, and usually even less, may be profitably burned in a multiple hearth furnace if the off-gas is first wet-scrubbed to a temperature below about 90.degree. F., then pre-heated by passing it through the center shaft of a multiple hearth furnace, before the pre-heated gas is burned. Such cooling of the off-gas by wet-scrubbing has the effect of lowering the moisture content of the wet-scrubbed gas sufficiently so that it may be advantageously pre-heated in the center shaft of the furnace and recycled to the hearths to assist in the combustion of sludge. In addition to providing desirable savings in auxiliary fuel usage, wet-scrubbed off-gas is unexpectedly cleansed of a sufficient amount of its corrosive components so as to permit ducting the wet-scrubbed gas in mild steel or cast iron equipment.

Abstract: A method and an apparatus of incinerating dewatered sludge without using an auxiliary fuel comprising pelletizing the partially dewatered sludge having a water content of 70 to 75%, drying the pellets with a heat source obtained by burning gases formed by dry-distillation and gasification, using part of the resulting dry-distilled gas in said drying step, dry-distilling the pellets by the sensible heat of a gas formed by gasification, gasifying the dry-distillation residues with air, water vapor and the remainder of said dry-distilled gas.

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.