Abstract: A mill recirculation system (10, 40) includes pulverizer means (14, 48), classifier means (12, 44) and burner means (16, 68) as well as a preestablished fluid flow path by which the pulverizer means (14, 48) and the classifier means (12, 44) are interconnected in fluid flow relation with the burner means (16, 68). In accord with the mode of operation thereof, a separation is had at the classifier means (12, 44) of the stream of the gaseous medium such that a portion of the gaseous medium is recirculated along with the oversize solid fuel particles back to the pulverizer means (14, 48) while the remainder of the gaseous medium is operative to convey the solid fuel particles that are of the desired size from the classifier means (12, 44) to the burner means (16, 68) for burning, i.e., firing, in the latter.

Abstract: An apparatus for supplying stationary small- to medium-sized heating plant with flowable solid fuel such as coal dust or coal breeze has a vacuum conveyor running from a fuel storage container of the apparatus to the heating plant for transporting the fuel from the container to the boiler. The blower of the conveyor has an aspiration port joined up with the container. The container has flexible walls of textile material and has an air blow-off line and a filter sheet for separating the coal dust from any coal dust-air mixture produced. This design makes it possible for the heating plant to be run automatically with the least leakage of dust and volatile substances out into the air.

Abstract: In a pulverized fuel-fired furnace (10), the temperature of the mixture of pulverized fuel and primary air leaving the mill (36) is measured and compared to a preselected minimum acceptable temperature. Whenever the measured mixture temperature drops below a preselected minimum, the flow damper (78) disposed in the tempering air duct (44) is closed to minimize the flow of tempering air therethrough and a heating fluid (62) is passed in heat exchange relationship with any ambient temperature air leaking past the flow damper in the tempering air duct thereby preheating the tempering airflow. Preferably, hot water (62) is circulated from the waterwall inlet header (22) of the water-cooled water walls (12) of the furnace (10) through a heat exchanger (60) disposed in the tempering air duct (44) and then returned back to the water-cooling circuit (24) of the water-cooled furnace walls at a location upstream of the circulating pump (26).

Abstract: The outline of a tangentially-fired furnace combustion chamber is arranged to show a representative windbox in one corner of the furnace. The secondary air is disclosed as supplied through one set of vertically tiltable nozzles mounted in the windbox. The secondary air supply conduit is mounted to feed the tiltable nozzles. The secondary air supply conduit section adjacent to the nozzles has straightening vanes forming channels in which independently controlled louvers regulate the total cross-sectional area of the channels to maintain the desired velocity of the secondary air through the nozzles.

Abstract: A direct-fired, pulverized coal-fired furnace 2, wherein the fuel supply system is modified so that a load carrying pulverizer 10 supplying pulverized coal to the furnace through a plurality of burners 4 may simultaneously also supply pulverized coal to a storage bin 16 for storage therein until needed to start-up, warm-up and stabilize the low load firing of the furnace 2 at a later time.

Abstract: A combustion system and method for a coal-fired furnace in which a splitter is provided in the main conduit leading from the pulverizer for splitting the stream of coal and air into two separate streams. One stream from the splitter is connected to a separator in which a quantity of air is separated from the mixture of air and coal. A low load burner assembly is provided which includes a first nozzle connected to the separator for discharging the bulk of the coal flow and some air into the furnace, and a second nozzle connected to the same separator for discharging the bulk of the air from the separator into the furnace. The other stream from the splitter is connected to a third nozzle which discharges its mixture of air and coal into the furnace to provide high load capability.

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 system receives raw coal which is routed through crushing, screening, pulverizing, classifying, and beneficiation stages with the de-mineralized fraction of the coal routed to a pulverized-coal-fired furnace, while the mineralized fraction is routed to a fluidized bed furnace.

Abstract: Supplying a fuel to a plurality of burners of a heating installation is performed by individually dosing a fuel by dosing elements to a plurality of burners with an excessive available amount of the fuel, withdrawing an unused amount of the fuel from the dosing elements, determining a difference between the available amount and the unused amount of the fuel to obtain an actual consumed amount of the fuel, comparing the thus obtained actual consumed amount of the fuel with the desired consumption amount of the fuel, and controlling the dosing of the fuel to each of the burner in dependence upon the results of the comparing steps.

Abstract: Disclosed is a method for firing a kiln as well as a method for producing cement clinker in which pulverized coal is initially entrained in an airflow of about 2% of the theoretical amount of air needed to combust the coal and transport it to a burner. Supplemental primary air heated sufficiently to vaporize volatiles in the coal is mixed with the coal flow in a burner, discharged into the kiln and hence ignited. Secondary combustion air heated to between 800.degree. F. to 1650.degree. F. and more is added in the kiln to effect the substantially complete combustion of the pulverized coal in the kiln.

Abstract: A fluidized-bed system for feeding coal or a coal-limestone mixture into a fluidized bed combustor, a perforated horizontal distributor plate dividing the chamber into upper and lower chamber sections, means for feeding solid fuel particles into the upper chamber section, a source of high velocity gas connected to the lower chamber section and passing through the plate into the upper chamber section for entraining the particles, means for heating the high velocity gas before it is introduced into the upper chamber, an entrainment section defined by converging upper sides of said fuel feeding chamber, and a stream splitting section disposed above said entrainment section and connected to a plurality of pneumatic transport lines each penetrating the distributor plate of a fluidized bed combustor and terminating in an outlet feedport.

Abstract: A kiln system and method of operating the same, wherein a firing kiln is heated with pulverized fuel, and a crusher for the fuel and an air cooled cooling device for the fired material are provided, with at least a portion of the cooling air being supplied to the firing kiln as secondary air after passing through the cooling device, and the pulverized fuel being pneumatically taken from the crusher to a separator, from which the greatest portion of the pulverized fuel is supplied to the burner and from which the conveying air containing a small portion of the pulverized fuel is fed to the cooling device as cooling air.

Abstract: A system for the comminution of coal, slurry formation and feed of the coal slurry to a fluidized bed reactor.

Abstract: A method for rapidly changing the amount of pulverized coal supplied to a coal-fired furnace (10) equipped with a coal pulverizer (20) from a first steady-state level to a second steady-state level in response to a change in operating load demand. The amount of pulverized coal supplied to the furnace is instantaneously increased by providing pulverized coal to the furnace from a source (42) independent of the pulverizer or instantaneously decreased by diverting away from the furnace a portion of the pulverized coal being supplied by the pulverizer.

Abstract: A first atmospheric bubbling fluidized bed furnace is combined with a second turbulent, circulating fluidized bed furnace to produce heat efficiently from crushed solid fuel. The bed of the second furnace receives the smaller sizes of crushed solid fuel, unreacted limestone from the first bed, and elutriated solids extracted from the flu gases of the first bed. The two-stage combustion of crushed solid fuel provides a system with an efficiency greater than available with use of a single furnace of a fluidized bed.

Abstract: A coal burner and rotary metal melting furnace incorporating the same is provided in the form of a generally cylindrical furnace rotatable about a horizontal axis and fired through one end with pulverized coal and preheated air through a burner structure which impinges the preheated air in a helical path against a conical spray of finely divided coal.

Abstract: Fine particulate solid fuel particles are delivered from a venturi ejector to a rotating double-armed distributor which distributes fuel and air sequentially to conduits leading to the burner ejector of a kiln. The distributor is sealed and pressurized with air so as to provide the conduits with additional pulses of air following the times at which they receive fuel and air from the distributing operation.

Abstract: Disclosed is a method for firing a kiln as well as a method for producing cement clinker in which pulverized coal is initially entrained in an airflow of about 2% of the theoretical amount of air needed to combust the coal and transport it to a burner. Supplemental primary air heated sufficiently to vaporize volatiles in the coal is mixed with the coal flow in a burner, discharged into the kiln and hence ignited. Secondary combustion air heated to between 800.degree. F. to 1650.degree. F. and more is added in the kiln to effect the substantially complete combustion of the pulverized coal in the kiln.

Abstract: A continuous process for the combustion of solid fuels in the presence of an aqueous liquid phase 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. Fuel is charged as a slurry in alkaline aqueous solution and contacted with combustion air so that the catalytic properties of both water and alkali operate to permit rapid and complete combustion at comparatively low temperatures. Temperatures in the adiabatic reactor are, however, permitted to exceed the critical temperature of the liquid phase. Under the conditions of the process, formation of nitrogen oxides is negligible, sulfur in the fuel goes to sulfur trioxide which dissolves completely in the alkaline liquid phase which also retains particles of ash and unburned fuel. The resulting flue gas is essentially free from objectionable pollutants.

Abstract: An improved fuel-air admission assembly having a plate disposed along the longitudinal axis of the coal delivery pipe. The leading edge of the plate is orientated across the inlet end of the coal delivery pipe so that the high coal concentration portion of the primary air-pulverized coal stream discharging along the outer radius of the main fuel pipe outlet elbow is separated from the low coal concentration portion of the primary air-pulverized coal stream discharging along the inner radius of the main fuel pipe outlet elbow. The trailing edge of the plate is orientated across the outlet end of the coal delivery pipe so that the high and low coal concentration streams are directed into the furnace through separate nozzles.

Abstract: A fluidized bed boiler feed system for the combustion of pulverized coal. Coal is first screened to separate large from small particles. Large particles of coal are fed directly to the top of the fluidized bed while fine particles are first mixed with recycled char, preheated, and then fed into the interior of the fluidized bed to promote char burnout and to avoid elutriation and carryover.

Abstract: The application discloses a particulate solid fuel combustion system for kilns and the like. A particulate solid fuel such as powdered coal, is supplied to a fluidized bed conveyor. Selected quantities of coal are withdrawn to air entrainment devices where the coal is entrained in a jet of a gas and delivered to a burner. The firing rate is controlled responsive to requirements of the kiln.

Abstract: The method of burning different sorts of solid fuel in a tunnel-like burner furnace comprises the steps of pulverizing the solid fuel particles to a size corresponding to optimum burning performance of the employed burners, supplying the pulverized particles in an air stream to the burners of the furnace and adjusting the supplied amount of pulverized particle-air mixture, and the amount of air in the mixture in accordance with the optimum burning performance of the burner. The burner furnace system for performing the method of this invention comprises a tunnel burner furnace having a plurality of ceiling burners and of side wall burners, a fuel distributor having a rotatable distributing channel communicating successively with respective burners and a dosing device connected to the input of the fuel distributor and adapted for adjusting the stream of the mixture of air with pulverized fuel particles.

Abstract: An apparatus and method are described for producing a combustible mixture of a solid fuel pellet made from organic fibrous material and a flammable gas or liquid. A suitable burner structure is described for burning the fuel mixture in an overfire system efficiently and producing a minimum of solid combustion products as ash. The flammable gas mixed with the solid fuel material may be made by burning pellets of an organic fibrous material.

Abstract: A method and apparatus for the preparation of coaldust for use with a preheater and a cement calcination apparatus. Exhaust gas from the preheater is mixed with a source of coal and input to a pulverizing mill. The output of the pulverizing mill passes through an air current separator and a cyclone separator. The output of the air-current-separator, a stream of coal gravel, is supplied as a fuel at a calcination point in the calcination apparatus. The exhaust output from the separator provides an input to the cyclone separator which separates coaldust from the gas. The exhaust from the cyclone separator is in part fed-back to a calcination point in the calcination apparatus and is also a part of the stream of gravel. The entire process is closed so that no burnable coaldust is lost to the atmosphere.

Abstract: This process is for devolatilizing coal to produce a volatile hydrocarbon gas leaving a residue of unburned coal. The volatile hydrocarbon gas and other coal or said residual coal are thereafter burned together in a common furnace. The volatilization of the coal may be carried out substantially endothermically, and preferably on the plant site where the burning of the volatilized hydrocarbon takes place together with other coal or the residue coal. The volatile matter is removed from the coal in a volatile state before the residue coal exits from the burner nozzle and then enters the combustion chamber where the volatilized hydrocarbon gas and residue coal are burned together. The removed volatilized hydrocarbon gas can be placed within the same coal burning plant to join with the unburned residual coal, passing to the burner to burn therewith.

Abstract: A method for the combustion of crushed solid fuel comprising crushing the fuel into a powder form, placing the crushed fuel into a storage bin and fluidizing the fuel within the bin, passing the fluid fuel through a de-airing pipe to partially compact the fuel, advancing the partially compacted fuel into a mixing chamber, passing regular pulses of compressed air through the mixing chamber so as to form a vena contracta in the mixing chamber thereby inducing the flow of partially compacted fuel into the compressed air and causing the mixture of fuel and compressed air to flow into a kiln or furnace.

Abstract: An ignition, warm-up and low-load-stabilization system for furnaces fired by pulverized coal. In conjunction with a system in which pulverized coal is sent directly from a coal mill to a load-bearing nozzle and in which combustion air is brought to the nozzles from an air preheater that uses hot furnace gases to warm the combustion air, ignitor nozzles are provided that are supplied by pipes bearing coal from which the drying air has been separated. Combustion air for the ignitor nozzles is heated by an independent heat source that heats the combustion air or a portion thereof to a temperature higher than that of the air supplied by the air preheater. Such a coal-fired ignitor burner can replace oil or gas-fired ignitors and warm-up guns and thereby reduce the amount of oil or gas used in ignition, warm-up, and low-load stabilization.

Abstract: Coal particles are discharged from a hopper into a common, vibrating feed pan which, in turn, distributes the particles evenly across the surface thereof and delivers the particles along the length thereof to a metering trough positioned below and along a longitudinal axis which extends across the discharge end of the pan. The metering trough divides the volume of coal particles into a plurality of equal batches, each of which, in turn, drops into a mixing device where the particles become airborne and are delivered into a feed conduit from whence they are fed to a furnace burner. By controlling the rate of vibration of the feed pan, variables such as moisture content of the coal and/or air, particle size and BTU content of the coal can be compensated for to maintain a desired temperature within the furnace.

Abstract: Apparatus is disclosed in which a coal burner pipe may be re-aimed into a rotary kiln. The burner pipe extends through a suitable opening provided in the associated hood of the kiln, with the discharge end of the burner pipe being so disposed as to discharge parallel to or obtusely to the axis of the kiln. Exteriorly of the kiln the coal burner pipe is provided with rigid angular pipe sections which can be reoriented relative to each other for effecting the re-aiming of the coal burner pipe within the kiln.

Abstract: Solid particles comprising combustible matter (e.g. coal) associated with or contaminated by inert matter (e.g. ash, rock) is segregated in a segregation zone into low density/small size and high density/large size fractions. The low density/small size fractions are passed to a utilization zone for conversion of the combustible matter. The high density/large size fractions are size reduced (e.g. by grinding) and either returned to the segregation zone, or passed at least in part, directly to the utilization zone. The conversion of the combustion matter proceeds more efficiently as a result. The segregation zone may operate by fluidized size/density segregation and in the utilization zone, the combustible matter may be at least partially combusted, preferably in a fluidized bed.

Abstract: Systems for the comminution, drying and dry feed of coal for combustion in fluid bed calciners, incinerators, or other combustion systems.

Abstract: An arrangement for supplying air to a boiler-furnace whereby an axial flow fan being used as a source of primary air may selectively take suction air from the atmosphere or from the discharge side of a fan being used to provide secondary air to the boiler. This arrangement will provide an increased inlet pressure for the primary air fan to thereby achieve increased stability and high system pressure for low load operation, thereby permitting the effective use of an axial flow fan as a source of primary air when such usage would otherwise be unjustified.

Abstract: Apparatus is disclosed for individually and independently controlling the distribution of powdered solid fuel to each of a plurality of individual burners. A plurality of fuel outlet ports respectively and individually corresponding to individual ones of the plural burners are aligned with and spaced from a respectively corresponding plurality of air outlet ports. The air oulet ports are individually and controllably supplied with pressurized air while a supply of powdered solid fuel is fed into the spaces between the fuel outlet ports and the air outlet ports. In the preferred embodiment, a baffle is disposed between each pair of respectively corresponding fuel outlet and air outlet ports.

Abstract: Both method and apparatus are disclosed for controlling the distribution of powdered solid fuel to one or more burners. The powdered solid fuel is caused to pass downwardly through an air current passing from an air inlet to one or more outlet ports. The total rate at which fuel is distributed is controlled by the rate at which air is supplied to the air inlet. In addition, each outlet port is provided with an individual adjustment for controlling the relative rates at which fuel is supplied through the various individual outlet ports. The construction of the distributor is such that the system may be controlled to distribute fuel continuously or in successive controlled impulses while at the same time controlling both the total amount of distributed fuel as well as the relative amounts of fuel distributed in the various outlet lines to the burners.

Abstract: A coal fired steam generating system including an auxiliary oil fired burner combined with an air heater. The air heater provides heated air that is adapted to heat and dry the coal for combustion, while hot products of combustion exhausting from the oil fired burner supply heat to a precipitator that raises its operating temperature to increase its collecting efficiency.

Abstract: Method and apparatus for upgrading subbituminous coal and/or lignite fuel product that does not comply with an applicable SO.sub.x :Btu standard during the combustion thereof. The fuel product is treated at the combustion site to lower the total moisture content thereof from between about 15 and 45 percent to between about 4 and 7 percent. Heavier weight ash particles are removed from the fuel product to lower the sulfur content thereof. The treated fuel product is burned while it is in the 4 to 7 percent total moisture range, thereby meeting the applicable SO.sub.x :Btu standard during the combustion process.

Abstract: Heterogeneous municipal solid waste is pneumatically separated in a first stage into relatively heavy incombustible and lighter weight combustible fractions. The first stage light combustible fraction is further pneumatically separated in a second stage into heavier grade fuel and lighter grade fuel fractions. In a third stage still further separation may be effected of the second stage lighter grade fraction into a heavier fraction suitable for other uses such as in the manufacture of certain building materials and a lightest fraction most suitable for air suspension boiler or kiln firing. Primary shredding of all of the solid waste to be pneumatically separated, and final reshredding of the fuel grade materials are provided for to attain maximum combustion efficiency.

Abstract: An energy system which burns refuse inside a steam chamber to drive a steam turbine and an electrical generator. In addition to the electrical energy produced, hot water and steam are delivered as by-products.

Abstract: Method and apparatus for direct coal firing of glass tank furnaces wherein pulverized coal entrained in an air stream is impelled through a nozzle into the furnace and combusted in the atmosphere directly above the melt in a glass furnace, to form a luminous flame, the direct coal firing preferably being used in conjunction with supplementary conventional heat sources.

Abstract: A combustion chamber has a lower end provided with a grate, and an inlet admits unclassified refuse into a comminutor wherein it is comminuted and forms a heavier particle fraction and a lighter particle fraction. The fraction having the heavier particles is directly admitted onto the grate, whereas the fraction having the smaller and lighter particles is subjected to a second comminution to convert the smaller particles into fine particles which are then admitted, either directly or indirectly, into the combustion chamber upwardly of the grate so that they become incinerated in the combustion chamber while floating therein. A method of incinerating refuse is also disclosed.