Abstract: Method and apparatus for generating steam in which water is fed directly into a combustion zone which is configured in such a manner that water cannot by-pass the zone. A steam generator may be comprised of three conduits arranged coaxially with one another which carry fuel, oxygen, and feed water to a fuel-oxygen mixing zone and a combustion zone. Alternatively, a generator may be comprised of two concentric conduits which carry water and a mixture comprised of fuel and oxygen to a combustion zone. Steam flows out of the generator through a restriction at one end of the outermost conduit. In one embodiment, the combustion zone extends into a housing which communicates with and is attached to the outermost conduit. The invention provides very high thermal efficiency and very low atmospheric emissions.

Abstract: A flare stack with increased flow velocity of gases. The flare stack includes a pipe having a flare tip. The flare tip has a top edge. A conical shield having an apical end and a base is secured to and spaced from the flare tip to allow gas to flow between the conical shield and the flare tip. The conical shield is open at the apical end adjacent the top edge of the flare tip. A source of forced gas, preferably air, provides a flow of gas between the conical shield and the flare tip. Preferably, the base of the conical shield is closed.

Abstract: A process for reducing carbonaceous deposits caused by the combustion of heavy fuel oil in high-compression, spontaneous-ignition internal combustion engines involves adding an additive such as ferrocene or ethyl ferrocene to a heavy fuel oil having a density of 0.9 to 1.01 kg/dm.sup.3 in an amount of 1 to 100 ppm prior to combustion of the fuel oil and combusting the fuel oil in the high-compression, spontaneous-ignition internal combustion engine. The additive is dissolved in the heavy fuel oil.

Abstract: A flame reaction member for gas combustion appliances comprises a flame reaction material, which is to be heated by a gas flame having been produced by a gas combustion appliance and which undergoes a flame reaction and colors the gas flame by the flame reaction. The flame reaction material comprises a glass compound, which is formed by mixing a flame reaction agent and a fused material with each other and fusing them together. The flame reaction agent is constituted of an oxide or a salt of a metal capable of undergoing the flame reaction. The fused material is capable of being mixed and fused together with the flame reaction agent and vitrified.

Abstract: A combustible fuel for diesel engines and a process for forming same in the form of a water in hydrocarbon emulsion wherein the mean water drop diameter is .ltoreq.4 .mu.m with a maximum diameter of .ltoreq.10 .mu.m.

Abstract: A process for producing energy from sulphur containing carbonaceous fuels comprises partially oxidizing the carbonaceous fuel to produce off gasses including carbon monoxide, hydrogen and hydrogen sulphide; removing hydrogen sulphide from the off gasses and combusting the off gasses from which the hydrogen sulphide has been removed to produce energy.

Abstract: A process for minimizing the formation of nitrogen oxides in the disposal of industrial waste streams containing chemically bound nitrogen, the process comprising the steps of passing a combustion gas stream at about 1200.degree. F. to about 2000.degree. F. to a combustion chamber; mixing an industrial waste stream with a selected mixing ingredient to provide a waste stream mixture having a composition such that adiabatic combustion of the waste stream mixture would yield combustion products having a combustion temperature of about 1500.degree. F. to about 2000.degree. F.; injecting the waste stream mixture into the combustion chamber and contacting same with the combustion gas stream to combust the nitrogen containing compounds to form a composite combustion gas stream having a temperature of from about 1500.degree. F. to about 2000.degree. F. The composite combustion gas stream can be vented to the atmosphere after, preferably, passing same through heat recovery equipment.

Abstract: A flare tip structure has a tubular component usually mounted at the top of a flare sack which emits waste gas into the atmosphere for disposal by combustion with the aid of one or more pilot burners. Several fluid injectors are mounted inside the component and emit cones of injection fluid, such as natural around the axis of the tubular component. A deflector assists the injectors in creating a cushion of fluid just above the opening of the tubular component to space the combustion flame away from the opening. This allows surrounding air to flow into the gap between the opening and the combustion flame and to mix with waste gas prior to combustion to suppress smoke.

Abstract: A combustion method wherein fuel is mixed with an oxidant mixture comprising a defined concentration of argon and nitrogen and combusted resulting in reduced generation of particulate pollutants. The argon increases the mass and the nitrogen increases the volume of the oxidant improving the combustion reaction. Alternatively argon is mixed with fuel and the resulting mixture subsequently mixed with oxidant for combustion.

Abstract: A method and apparatus for controlling NO.sub.x produced by a natural gas fired combustion source includes establishing a control curve for the combustion source for indicating NO.sub.x levels based on steam injection rates and fuel flow rates provided to the burners. The atomizing steam injection flow rate provided to the burner is measured as well as the fuel flow rate. A NO.sub.x level is determined for the combustion source based on the atomizing steam injection flow rate, the firing rate, and the fuel flow rate. NO.sub.x levels are lowered by adding atomized steam to the burners according to the pre-programmed control curve.

Abstract: A system including a water container, a compressor, a pressure line connected from the compressor to the water container to bubble air through water in the container, a suction line taking air back to the compressor for recirculation, and a connection to the air intake of a combustion device for injecting some of the recirculating air into the intake air stream of the combustion device.

Abstract: The efficiency of fuel combustion is improved by adding to the fuel an additive that includes tin, antimony, lead and mercury. The additive may include by weight 60-80% tin, 15-30% antimony, 2-7% lead and 3-12% mercury.

Abstract: A system including a water container, a compressor, a pressure line connected from the compressor to the water container to bubble air through water in the container, a suction line taking air back to the compressor for recirculation, and a connection to the air intake of a combustion device for injecting some of the recirculating air into the intake air stream of the combustion device.

Abstract: Injectors are disclosed for use in an underoxidized burner having a single or double stage internal combustion chamber for receiving gaseous or liquid fuel such as diesel for mixture with air or oxygen and subsequent ignition by a spark plug. The injector includes feed conduits or tubes for simultaneously conducting air and fuel to a mixing device having a baffle arrangement against which separately injected air and fuel impinge causing a complete air/fuel blending which is ignited, burned and exhausted. The injector may accept effluent gases for mixing with water to produce maximum hydrogen H.sub.2 from fuels. A lamina flow is produced which is folded over and reversed in direction within the combustion chamber.

Abstract: A system for providing heated fluidized bed gasification of a residual waste liquor provides a bed of granular material and a source of liquor provided to the material bed. An injector is situated in the material bed and communicates with an air source, a fuel source and a steam source. Fuel and air are combusted in the injector and mixed with the steam which forms a combustion product and steam mixture which is in turn injected into the material bed. The combustion and mixing is separated from the bed material by being confined within the injector. The injector is a bubble cap having at least one hole or an injector made of a porous ceramic material.

Abstract: A process for the in-situ production of an effluent sorbent-oxide aerosol during the combustion of a hydrocarbon containing fuel whereby the effluents are removed from the resultant gaseous hydrocarbon stream comprises admixing an aqueous solution of the sorbent with the fuel, atomizing and combusting the mixture under controlled conditions so as to generate the effluent sorbent-oxide aerosol.

Abstract: A burning process comprising the steps of emulsifying fuel oil with water and aerating the emulsion in a mixing tank until there is a substantial reduction of its density. The emulsion is then stabilized in a resting tank under adequate temperature and pressure conditions for maintaining an deaerating the emulsion. The stabilized emulsion is conducted to a burner nozzle where it is pulverized into particles by means of abrupt decompression in an environment poor of air.

Abstract: A process for the in-situ production of an effluent sorbent-oxide aerosol with promoter during the combustion of a hydrocarbon containing fuel whereby the effluents are removed from the resultant gaseous hydrocarbon stream comprises admixing an aqueous solution of the sorbent and promoter with the fuel, atomizing and combusting the mixture under controlled conditions so as to generate the effluent sorbent-oxide aerosol.

Abstract: A method and apparatus for reacting sodium vapor with gaseous chlorides in a flame to produce nanoscale particles of un-oxidized metals, composites and ceramics. The flame is operated under conditions which lead to condensation of a NaCl by-product onto the particles. The condensate encapsulates the particles and aids in controlling desired particle size and preventing undesirable agglomeration among the particles during synthesis. Following synthesis, oxidation of the particles is inhibited by the encapsulation and handling character of the products is greatly enhanced. Electron microscopy has revealed that synthesized products are composed of discrete nanoparticles in a NaCl matrix. The NaCl encapsulate has been effectively removed from the particles by both washing and known sublimation technique at 800.degree. C. under low pressure.

Abstract: A method and apparatus for the on-site disposal of landfill gas (LFG) condensate is disclosed. Any contaminants in the condensate are incinerated in an LFG flare. The LFG condensate is first pressurized and then injected, in an atomized state, into a combustion zone of the LFG flare. The LFG condensate is pumped from a plurality of sumps to an accumulator. A pump controlled by a liquid level sensor cycles on and off in response to the level of condensate in the accumulator. The pressurized condensate is delivered to a nozzle via a conduit system. The pressurized condensate is atomized by the nozzle and the resulting mist is directed into the combustion zone where it is vaporized. Any contaminants in the condensate are incinerated along with similar contaminants in the LFG.

Abstract: A system for providing heated fluidized bed gasification of a residual waste liquor provides a bed of granular material and a source of liquor provided to the material bed. An injector is situated in the material bed and communicates with an air source, a fuel source and a steam source. Fuel and air are combusted in the injector and mixed with the steam which forms a combustion product and steam mixture which is in turn injected into the material bed. The combustion and mixing is separated from the bed material by being confined within the injector. The injector is a bubble cap having at least one hole or an injector made of a porous ceramic material.

Abstract: An apparatus for decreasing nitrogen oxides in a combustion device of Stirling engine which performs continuous combustion includes a combustion chamber, means for supplying the combustion chamber with fuel and air, an exhaust passageway for discharging exhaust gas produced by combustion in the combustion chamber, a catalytic unit arranged in the exhaust passageway for purging toxic components contained in the exhaust gas discharged, and hydrogen supply means for supplying hydrogen gas to the exhaust gas which enters the catalytic unit. The hydrogen gas is supplied to the combustion exhaust gas which has entered the catalytic unit, and the combustion exhaust gas is then catalytically reduced in an environment of a comparatively low temperatures of less than 250.degree. C., whereby the nitrogen oxides in the exhaust gas are decreased.

Abstract: The present invention provides an improved emissions reduction system for lowering the emissions of NO.sub.x generated by the combustion of hydrocarbons. The present invention further provides a method for lowering the emissions of NO.sub.x generated by the combustion of hydrocarbons.

Abstract: The invention relates to a method for preventing ice from forming on a cooling system for air by adding an antifreeze to the air being cooled by the cooling system. The cooled air containing the antifreeze is then transferred a turbine engine, wherein the air and antifreeze are burned in the turbine engine. A condensed water and antifreeze mixture is also burned in the turbine engine. The invention also relates to an apparatus for preventing ice from forming on the refrigeration system for cooling air. The apparatus includes a sprayer for spraying the antifreeze onto the refrigeration system and/or the air being cooled by the refrigeration system, a collector for collecting a condensed water and antifreeze mixture, and a pump or transferring means for transferring the condensed water and antifreeze mixture to the turbine engine, where the antifreeze and condensed water mixture is burned.

Abstract: The invention provides a method for reducing the emission of NO.sub.x in a pressurized fluidized bed combustion process comprising (a) combusting reaction products in the presence of a sulfur absorbent in a pressurized fluidized bed at a pressure of at least 5 bar to form a flue gas comprising dust particles and an initial concentration of NO.sub.x, (b) reacting the NO.sub.x in the flue gas with a substance which reduces NO.sub.x in a first reaction zone to form a flue gas which has a lower NO.sub.x concentration as compared to its initial NO.sub.x concentration, wherein the absolute pressure of the flue gas is at least 5 bar and the temperature of the flue gas is at least 450.degree. C. in the first reaction zone, and (c) reducing the NO.sub.x concentration in the flue gas provided by step (b) in a second reaction zone by contacting the gas with a solid surface comprised of flue gas dust particles.

Abstract: A process for the addition of ferrocene to combustion or motor fuels involves an improved metering of the additive ferrocene into the combustion chamber of an internal combustion engine or a combustion system. The process utilizes the sublimation properties of ferrocene in that ferrocene is passed through sublimation into a stream of combustion gas or a substream thereof and with the combustion or motor fuel, which is present as a vapor or finely distributed as solid or liquid particles, fed to a chemical conversion through combustion. A preferred application consists of loading the combustion chamber of a diesel engine equipped with a diesel particulate filter with a carrier gas stream enriched with ferrocene vapor in a sublimator.

Abstract: A novel process and apparatus for continuously producing very fine, ultrapure ceramic powders from ceramic precursor reactants in a self-sustaining reaction system in the form of a stabilized flame thereof to form ceramic particles and wherein the thus formed ceramic particles are collected in the absence of oxygen.

Abstract: This invention provides for water-oil emulsions comprising water, oil and a minor emulsifying amount of the reaction product of: (A) at least one saturated or unsaturated aliphatic monocarboxylic acid of about 12 to about 24 carbon atoms; (B) at least one acid of the general formula C.sub.19 H.sub.n COOH, wherein n is a number in the range of about 27 to about 31, and having a phenathrene nucleus; and (C) at least one amine. In one hydroxy embodiment, the oil employed in these emulsions can be any oil, the water content of these emulsions being up to about 30% by weight. In a preferred embodiment, the oil employed is crude oil. These emulsions can be facilitatingly pumped through a conduit even when the oil employed is a viscous crude oil. These emulsions are useful as a combustible fuel when the water content is below about 30% by weight.

Abstract: The invention presented relates to a process for reducing nitrogen oxides emissions from a gas turbine. The process involves forming an emulsion of water and fuel oil and simultaneously combusting the thusly formed emulsion with natural gas in a gas turbine.

Abstract: In a device for removing nitrogen oxides from exhaust gas of a combustion device by spraying a treatment agent capable of chemically reducing nitrogen oxides contained in the exhaust gas from an injector in a combustion chamber or an exhaust passage of the combustion device, the effectiveness of the treatment agent is optimized by detecting a combustion condition of the combustion device, and supplying water and at least one treatment agent in a selective and alternating manner according the detected combustion condition.

Abstract: To minimize the NO.sub.x emissions by means of water in the combustion of a fuel, without incurring the risk of higher CO emissions arising instead, the sensitive ignition zones of a burner (A) are penetrated by compact water jets (11) (solid jets) at the point where a freshly fed fuel/air mixture is continuously ignited anew, in such a way that these zones are not disturbed. In this way, instabilities, flame pulsations and/or poor burn-out, which are responsible for a rapid increase in CO emissions during combustion, are prevented. In the interior of the flame, the water jets (11) then burst open and the water is distributed exactly where it counteracts the NO.sub.x emissions.

Abstract: A process for preparing an oil-in-aqueous phase emulsion and removing contaminants from a contaminated hydrocarbon. The process comprises mixing a contaminated hydrocarbon with a reactant and an emulsifying composition. Contaminants are removed from the contaminated hydrocarbon either during the mixing, after the mixing, or during the combustion of the mixture, or after combustion of the mixture such as from combustion flue gases.

Abstract: An apparatus, for improving fuel combustion efficiency, comprises a fuel additive made from a formulation of metals as a plurality of identical cones (24), each of the cones being located within a magnetic field of a pair of permanent ferrite magnets (30) and the apparatus being locatable in a fuel line near the point of fuel combustion.

Abstract: An apparatus and method for enhancing the efficiency of a combustion process and thereby reducing undesirable emissions in which a solid combustion enhancing substance is converted into a highly dispersed, gas-transportable state at a controlled rate and is subsequently conveyed into the zone of combustion. The use of a substance in its solid state eases handling and avails highly effective materials for combustion and enhancement while the necessary conversion of the substance from one state to another enables a high degree of control as to its rate of addition to the combustion process. The substance's highly dispersed state when it enters the combustion process maximizes its effect.

Abstract: A method and apparatus are employed to reduce the sulfur dioxide produced by the combustion of a sulfur-containing fuel in a combustion chamber. Part of the combustion air is introduced into the combustion chamber with and closely adjacent the fuel. Another part of the combustion air is introduced into the combustion chamber above and downstream of the fuel and relatively remote therefrom under conditions which buffer the flame front and reduce peak flame temperatures therein. Finely divided limestone particles or the like are aspirated into the combustion chamber by the air introduced above the fuel and distributed thereby throughout the gases flowing downstream through the combustion chamber wherein the limestone particles are calcined to lime particles which react with the sulfur dioxide in the combustion reaction gases to produce calcium sulfate. There is no premixing of the particles and the aspirating air before they enter the combustion chamber.

Abstract: A passive ferrocene injection system provides a container that defines an internal reservoir holding a quantity of solid phase ferrocene. A means is provided for maintaining an elevated reservoir temperature sufficient to produce a vapor of ferrocene. The reservoir is connected to the air inlet system of a combustion device in such a manner that the ferrocene vapor is metered into the air inlet stream. One portion of this connection is a flow orifice metering ferrocene vapor from the reservoir at least by diffusion, and more normally, by diffusive and convective transport mechanisms.

Abstract: A process and apparatus for combustion of carbon black enriched gaseous hydrocarbon fuels in which carbon black particles are entrained in a carrier fluid and injected through a center nozzle of a fluid injector into a combustion chamber, the fluid injector having an outer nozzle concentrically disposed around the center nozzle forming an annular chamber between the center nozzle and the outer nozzle through which at least a first portion of a gaseous hydrocarbon fuel is injected into a combustion chamber forming a carbon black enriched gaseous hydrocarbon fuel. The carbon black enriched gaseous hydrocarbon fuel is subsequently mixed with combustion air and burned producing a highly luminous flame.

Abstract: An improved method of reducing the amount of sulfur dioxide in combustion gases generated by the combustion of a sulfur-containing fuel in a combustion chamber. The improved method comprises introducing a sorbent composition capable of interacting with sulfur dioxide into a zone of the combustion chamber above the fuel and flame area, such that the sorbent composition is distributed throughout the combustion gases and interacts with sulfur dioxide to remove sulfur dioxide from the combustion gases in the form of a solid inorganic sulfate. The sorbent composition introduced into the combustion chamber comprises: (a) 100 parts by weight of a sorbent; and (b) about 0.25 parts to about 60 parts by weight of an enhancer, said enhancer comprising: (i) about 15% to about 75%, by weight of the enhancer, of a hydrated inorganic salt; (ii) about 25% to about 85%, by weight of the enhancer, of a clay; and (iii) 0% to about 10%, by weight of the enhancer, of a combustible liquid.

Abstract: The presence of the oxides of nitrogen in the exhaust gas leaving a regenerator is limited by injecting water or water vapour into the regenerator 1 during its firing phase and causing the water or water vapour to reach the combustion chamber 26 of the regenerator 1 by way its heat storage bed 11 which has been preheated during a previous heat collecting phase.

Abstract: The vapor pump constituted by a mass and heat exchanger comprises an outer enclosure, a set of exchanger tubes disposed inside the enclosure and extending lengthwise therein, opening out at one of the ends in a first radial plane and at their other ends in a second radial plane, which radial planes include means for positioning and supporting the tubes and for closing the empty spaces in the section of the enclosure situated outside the tubes, thereby defining between said radial planes both a first gaseous fluid flow circuit inside the tubes, and a distinct counterflow second fluid flow circuit inside the enclosure but outside the tubes. One of the first and second gaseous fluids constituted by moist hot combustion products from a thermal process while the other gaseous fluid is constituted by new combustion air. Humidifier means are provided for humidifying the air inserted into the enclosure.

Abstract: Disclosed herein is an emission control system including an air pretreatment system for enhancing the ability of air passing therethrough to absorb moisture, a humidification chamber having an inlet and an outlet, the inlet being attached to the air pretreatment system, the pretreated air passing from the air pretreatment system into the inlet and through the humidification chamber so that it is humidified at a consistently controllable rate in its passage through the humidification chamber to and out of the outlet.

Abstract: In a firing installation, fresh air (6) is drawn in and mixed with a fraction of flue gases (7), which are taken from the combustion chamber (1), by means of a fan (5) which acts outside of the casing of the firing installation. The fresh air/flue gas mixture (8) thus formed flows on its way to the combustion chamber (1) through a first heat exchanger (2a) whose caloric preparation is accomplished by the flue gases (7) fed in. In the combustion chamber (1) itself, this mixture flows through a heat exchanger (2) placed there. Before the mixture (9) thus preheated is fed as combustion air to a burner (4), it undergoes a further mixing with flue gases via a number of jet injectors (3), which further increases the temperature of this combustion air (10), with an optimized flue gas fraction.

Abstract: The formation of nitrogen oxides during the operation of burners for solid, liquid, and gaseous fuels is reduced by means of an exhaust gas feed-back system. The exhaust gases are injected into a combustion chamber through openings provided in the region of stabilizer via a flame pipe and, by choice, also around the flame pipe. Preferably, the combustion air as well as the exhaust gases are activated by an active aerosol. The exhaust gas feed-back is effected by means of a longitudinally slidable adaptor pipe and an adaptor pipe shoulder enclosing the flame pipe at least partly. The regulation of the exhaust gas streams is achieved by displacing the adaptor pipe and the adaptor pipe shoulder.

Abstract: In this process for the selective noncatalytic reduction of the emission of pollutants from oil-fired boiler plants, chemical compounds which affect the combustion process are admixed, in solutions miscible with the liquid fuel, in metered amounts to the liquid fuel or to the combustion air, among these compounds being salts of organic acids, such as naphthenates, octoates, tallates, salts of sulfonic acids, saturated or unsaturated fatty acids, such as oleic acid, and tall oil, with metals from the group of K, Ba, Mg, Ca, Ce, Mn, Fe; rare earth metals; organometallic compounds, such as carbonyl compounds, mixed cyclopentadienylcarbonyl compounds, or aromatic complexes of the transition metals Fe or Mn. For the purpose of minimizing the NO.sub.

Abstract: An apparatus and method for enhancing the efficiency of a combustion process and thereby reducing undesirable emissions in which a solid combustion enhancing substance is converted into a highly dispersed, gas-transportable state at a controlled rate and is subsequently conveyed into the zone of combustion. The use of a substance in its solid state eases handling and avails highly effective materials for combustion and enhancement while the necessary conversion of the substance from one state to another enables a high degree of control as to its rate of addition to the combustion process. The substance's highly dispersed state when it enters the combustion process maximizes its effect.

Abstract: Disclosed is a system for regulating the efficiency of a combustion process by detecting radiant energy emitted from ash particles entrained in the gas stream exiting the combustion chamber of a boiler or incinerator. The intensity of selected wavelengths of light emitted from the particles is indicative of the temperature of the particles. The change in the intensities of the selected wavelengths of light, and thus of the temperature of the gas stream at the furnace exit, is monitored, and a feedback control mechanism is used to regulate one or more combustion, pollution control, or heat transfer parameters thereby maximizing the thermal efficiency of the combustion process in the boiler or incinerator.

Abstract: A fire vortex display for providing an interesting fire display for decorative and attention getting purposes. The display utilizes a burner for burning a gaseous or liquid fuel, typically in a very fuel rich mixture. The burner is located at one end of a normally vertical transparent tube such as a Pyrex tube, with a blower blowing air into the tube adjacent to the burner in a substantially circumferential manner to provide a swirling action for the flame given off by the burner as the flame proceeds upward into the tube. A second transparent tube concentric with and somewhat larger than the first tube is provided over the first tube, with the region between the two tubes being ducted to form the inlet for the blower. This keeps the outer tube cool so that the fire vortex can be observed from a position close thereto and the outer tube even touched by an observer without danger thereto.

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: A burner assembly in which an inlet is located at one end of an annular passage for receiving fuel, and an outlet is located at the other end of the passage for discharging the fuel. A register assembly is provided which includes an enclosure for receiving air and a divider for directing the air from the enclosure towards the outlet in two parallel paths extending around the burner. Registers are disposed in each of the paths for regulating the quantity of air flowing through the paths and an injector is provided in the outer path for injecting sulfur adsorbent into the secondary air stream.

Abstract: Production of oxides of nitrogen during combustion of liquid fuel can be reduced by burning at relatively low temperatures of about 1400.degree. C., by first producing a special combustible gaseous mixture of superheated steam, fuel vapor, and combustion air. Water is fed (9) to the apparatus in quantities of about 2 to 4 parts for each part of fuel (10). Then the fuel is vaporized (8) in a stream of the superheated steam. This avoids fuel cracking and formation of long-chain hydrocarbons. Preheated air (13,14,15) is added (17) in slightly over stoichiometric proportions. The resulting mixture is burned (2) and the hot effluent is used to heat the evaporator (6,7,8) and the air preheating chamber (15), with a bypass (20) equipped with a throttle (22) being used for regulation of evaporator temperature. For start-up, an external hot air source (23) or electric heat (24) can be used. The remaining heat in the effluent can be captured in a conventional heat exchanger.