FI67396B - FOERFARANDE FOER PRODUCERANDE AV EN BRAENNBAR GAS - Google Patents

Description

r-1 ANNOUNCEMENT, „-, λ ^ M ^ UTLXGCNINGSSKRIFT 6739 6 ^ ^ (51) H.Jt / fctCl3 C 10 B 53/02 // C 10 J 3/00 FINLAND — FINLAND (21) P» tenttJh »lcG «Sut —ΓκβιΚίηβΜο *», 772777 (22) HtlnwlfW - AwBtahH ^ 21 .09.77 (23) AllM | * M-Glk% Madaf 21.09.77 (41) TbWmc | »Wch« lMl - Mm dfutfg 22 03 78

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Patent and Regulatory Procedure AmMun etiagd odi utUkrtfwn pabNurad 30.11.8 ^ (32) (33) (31) Pjrr * «* y <« μοΙ> μμ »Bftrd prtorfc * 21.09.76 USA (US) 7252 ^ 9 (71) (72) Rudolf Wilhelm Gunnerman, 2800 City View Drive, Eugene, Oregon, USA (US) (7 * 0 Oy Kolster Ab (5 * 0 Method of Production of Gas) - Förfarande för producerande av en brännbar gas This invention relates generally to fuel and in particular to a method and apparatus for producing a combustible gas from organic fibrous materials which burns to produce a larger amount of kJ than hitherto available gases made from wood and agricultural waste products.

In the past, it has been proposed to burn wood and other organic wastes under conditions that produce a combustible gas that can later be burned as a fuel. The wood is burned in a vessel commonly referred to as a carburetor or extraction boiler, which is usually cylindrical with a diameter of about 120 cm and a height of about 360 cm, or with similar proportions. A variety of wood waste, such as sawdust or other wood waste material, is incinerated at the bottom of this high and slender tank, from which air is slowly added. The wood has a high percentage of water and is burned under conditions producing a temperature of about 650 ° C and a gas containing some relatively low molecular weight hydrocarbons and oxides such as methane, carbon monoxide and carbon dioxide. The purpose of these processes is to convert only the carbon of the wood into combustible gases, so the amount of kJ contained in the gas is small. Consequently, gas has not been used much in industry.

During the 1940s and 1950s, a gasification device similar to the one just described was used in Germany and other European countries to make a gas substitute for diesel and gasoline in motor vehicles, but there was a considerable loss of power in the vehicle.

Po. it is an object of the invention to provide an improved process for producing a combustible gas from an organic fibrous material. It is a further object to develop a method for producing a combustible gas for use as an industrial fuel, which method can be implemented in a commercially viable device.

It is a further object of the invention to provide a method for converting organic fibrous materials, such as wood waste, into combustible gas, resulting in significantly more kJ units (energy units) than previously available fuels made from sawdust and similar wood waste. It is a further object of the invention to provide an improved fuel gas which is produced by the combustion of organic waste and which not only contains combustible products obtained by converting carbon into combustible gases, but which also contains combustible, nitrogen-containing gases or dispersed small particles.

The method according to the invention is characterized in that it comprises supporting a compressed mass of free-flowing fuel spheres containing organic fibrous waste, on a grate perforated in the furnace, flowing air upwards through the grate and , igniting fuel balls near the grate and burning thermally insulated cubes while the air flows through them at a rate such that the temperature at which the fuel balls burn is 1480-1930 ° C and the balls just above the burning balls carbonize into charcoal balls, and each alkali metal in the fuel balls and other non-combustible material, which is usually removed from the bottom of the furnace as ash, instead reacts with airborne solids to form a combustible gas which is mixed with other combustible gases which are deactivated by the oxidation of the carbon in the combustion furnace and which are removed with said other gases from the upper end of the furnace to affect the heat generated when said combustible gases are burned and increase the kJ above that obtained by burning only said second gases.

Other objects will become apparent from the following description with reference to the accompanying drawing, in which an embodiment of the invention is shown schematically.

These and other goals are achieved po. according to the invention, in general, by developing a process for burning ball-sintered organic fibrous material in air under conditions in which the nitrogen in the air chemically combines with the combustion products to produce combustible gaseous products mixed with carbon compounds obtained from fuel combustion. It has been found that it is possible to produce a gas which burns up to four times more kJ than when burning organic fibrous fuel by burning fuel balls made by compressing organic fibrous material such as sawdust or other wood waste material, peat litter and the like. , in the vessel, while holding the heat insulating ball layer over the combustible mass and distributing air substantially evenly through the combustible mass at a rate such that the temperature of the combustible mass is at least about 1480 ° C. The gas evolved at such a temperature is believed to contain flammable, gaseous carbon compounds and gaseous nitrogen compounds formed by the chemical reaction of nitrogen with fuel components such as alkali metals (mainly sodium and potassium), calcium and other substances. The combustion of these nitrogen-containing combustion products, as well as the combustion of substances derived from the carbon of the fuel, is believed to be the reason for the surprisingly large amount of kJ obtained when the combustible gas burns.

The thickness of the fuel mass above the combustible fuel is preferably matched to the air flow fed to the combustible fuel so that the temperature is about 1650-1930 ° C in the middle of the combustible mass. In this case, the fuel burns in the same way as the fuel in the blacksmith's furnace and the fuel balls in the insulation layer just above the burning fuel become charred and largely converted into a charcoal layer. The fuel balls, which are preferably manufactured in accordance with my previous invention described below, should be free flowing and can be continuously fed to the fuel bed in a controlled manner from above. Alternatively, the fuel burner can be provided with a device that monitors the fuel height and triggers the fuel supply mechanism when the fuel bed height reaches a point where more fuel is needed to maintain an insulating ball bed that maintains a combustion temperature of about 1480 ° C or higher. A commercially available device sold under the trade name "Bindicator" can be used for this purpose.

According to the invention, any suitable organic fibrous material can be incinerated, such as, for example, agricultural waste such as straw, acan, etc., or sawdust, shavings, sawdust, peat litter, paper and the like.

Po. Embodiments of preferred fuel balls to be burned in accordance with the invention are described in U.S. Patent Applications Serial Nos. 646,514 (filed January 5, 1976) and 700,035 (filed June 25, 1976), the disclosures of which are incorporated herein by reference. According to the process described, the organic fibrous material is ball sintered into a form in which it can be burned substantially evenly in a natural process, including adjusting the fibrous particle size to a maximum of about 85% of the minimum ball size to be formed, substantially adjusting the fiber moisture content to about 16-28% by weight, and twisting and pressing of the fibrous material, when it has a controlled moisture content, into substantially symmetrical spheres with a maximum size not exceeding 12.7 mm.

In a preferred embodiment of the process, the organic fibrous material, such as agricultural or wood waste material, is conveyed by a conveyor designed to separate rocks, metal and other non-combustible contaminants from the fuel, a hammer mill, etc., where the organic fibrous material is ground to a substantially uniform particle size of about 85% of the minimum size of balls to be formed, and the ground material is then conveyed to a hot air dryer with a moisture content of about 16-28% by weight water, and then the product with adjusted size and water content is conveyed to a ball sintering machine equipped with its own measuring screw through the compression molds of the mill, and the ball thus obtained is dried until its moisture content is substantially in equilibrium with the atmosphere. The fibrous material is compressed under pressure and the temperature of the ball in the compression mold is about 162.8-176.7 ° C.

Although the moisture content of the organic fiber material is usually more than 28% by weight and the material requires drying, it is to be understood that if a material with a moisture content of less than 16% is available for ball sintering, its moisture content must be adjusted by wetting or the like so that its moisture content is about 16-28% before ball sintering. According to the invention, the moisture content can be as wide as 16-28% by weight, but it has been found that the best results are obtained when the moisture content of the organic fiber at the time of ball sintering is about 20-24% by weight, so the moisture content should preferably be in this lower range. The surface moisture can be removed from the balls by blowing air on them as soon as they come out of the ball mill.

It has been found that by adjusting the particle size of the organic fiber to about 85% or less of the minimum size of the ball to be ironed and adjusting the moisture content to about 16-28% by weight of free water prior to compression, preferably about 20-24%, a ball having a protective, waxy surface formed by seeping from the fibrous material and burning substantially evenly without forming a harmful amount of ash, provided that the shaping and pressing is performed at a temperature of about 162.8 to about 176.7 ° C. In order for the burning rate of the ball mass to be substantially uniform, the balls are dried after their formation so that their moisture content is substantially uniform and in equilibrium with the ambient air. These balls can be used to produce a combustible gas according to the invention. The balls can be easily transported with a commercially available inclined belt conveyor or a standard loading device. The balls have a substantially uniform shape and size and can be transported by compressed air if desired.

The shape of the balls should preferably be cylindrical or planar or the like, and their maximum diameter should be in the range of about 3.175 mm to about 12.7 mm. The actual ball size is determined by the external surface area relative to the composition of the internal material of the ball. The maximum thickness of the ball in each direction is rarely greater than about 25.4 mm and rarely less than about 3.175 mm. The absolute density of the balls made according to the invention is more than 22.679 kg 3 6 67396 per 28.32 dm was per cubic foot and is often 29.484-40.823 kg / 3 28.32 dm or more at a moisture content of 13%. The density of the particles from which the balls are made is about 4.536-13.608 kg / 28.32 3 dm at the same moisture content. On the other hand, commercial Pres-to-log1 has an absolute density of less than 29.484 kg / 28.32 din and is thus lighter than water.

The device used in carrying out the process of the invention can be modified. The previous high and narrow vessel does not need to be used to produce carbonaceous gases from wood waste. Preferably, in fact, a vessel with a cross-section slightly larger than its height is used. For example, a vessel made of cold-rolled steel with an upper cylindrical chamber and a substantially conical base can be used. This vessel has a closed top end through which a hole can be accessed to its weather space and has a central opening for supplying fuel to the fuel bed. A pipe can be welded to the upper end, the end of which is around the fuel supply opening and in which a standard air barrier can be installed to prevent gas losses. A small conical sink for fuel storage can be installed over the air barrier or some other reliable source of fuel balls can be connected to the pipe. A monitoring device, such as a Bindicator, can be mounted on top of the tank so that its sensor is at the desired level and is connected to a valve operated by the solenoid in the tube between the hose and the air barrier to automatically adjust the height of the fuel layer in the tank. For safety reasons, a safety valve can also be installed at the top of the vessel, which reacts to a pressure of, for example, 2,268 kg.

A perforated stainless steel plate supporting the fire layer is positioned across the tank at a distance from the top of the conical bottom of the vessel. This plate has substantially evenly spaced holes having substantially the same cross-sectional area so that the air coming from below is distributed substantially evenly through the fire layer. There is an opening in the wall of the vessel close to the fire layer for acetylene as well, or in between for insertion, with which the initial ignition of the fuel supported by the plate is performed. Preferably, a perforated edge is left along the circumference of the plate so that no air enters the fuel layer along the sides of the vessel. In this way, a protective layer of non-combustible fuel is formed around the fuel layer against the inner wall of the vessel and this does not require insulation.

7 67396

However, in some cases, it may be desirable to use a jacket around the bottom of the container and to circulate the air supplied to the container through the jacket to preheat it. In other embodiments, it may be desirable to cover at least that portion of the vessel wall around the fire layer with ceramics, e.g., fire bricks.

At the top of the bottom of the vessel there is an opening for supplying air under the perforated support plate of the fire layer. A pipe or other line is attached to the container around the opening and connected to an air source. The connection by which the pipe is connected to the container may be T-shaped, with one branch of the T being located vertically to collect substances in the fuel, such as rocks, scrap metal, etc., which do not burn and fall through the holes in the plate. The branch may have a lid that is removed regularly to remove non-combustible material.

The gas produced by burning the fuel is removed from the vessel at a point above the fuel bed. An opening can be made in the side wall of the container for this purpose. The orifice may be connected by a pipe directly to a burner burning fuel, or to a suitable tank or other gas storage container.

The gas produced according to the invention can be used to produce energy in any suitable device which burns the combustible gas. It can be used, for example, to produce steam for heating or industrial purposes or to generate electricity. At the combustion temperatures of the fuel, pyrolysis of the fuel is believed to take place, forming chemical compounds of the gas. As noted above, pyrolysis products include e.g. compounds produced by the combination of nitrogen in the air with the components of the fuel. When this mixture burns, a much higher amount of kJ is obtained than if the gas contained only carbon products from the fuel. In a gasifier such as the one described, it was found that when the fuel was manufactured from previous applications! was burned in a device of the type described at a pressure of about 0.07 kp / cm, an amount of kJ was obtained which was about four times the amount obtained by burning the fuel in an open furnace under normal conditions. During the hour when 3 about 47 kg of fuel was burned in an air volume of about 7080 dm per minute at a water column pressure of about 139.7 mm, gas was obtained which, when burned, generated 4,222,000 kilojoules. When the same fuel balls were burned under normal conditions to obtain reaction products, only carbon 8 67396

From Iesta, about 9,495 kilojoules per 0.453 kg point, or 987,480 kilojoules per about 47 kg, were obtained. These experiments were performed in a Heil Drum Dryer with a capacity of 14.77 million kilograms of joules per hour, burning natural gas as a normal fuel. After 72-96 hours of continuous operation of the gas generator, eight 1-hour experiments were performed with the same kJ production.

According to the drawing, in a preferred embodiment of the device there is a carburettor 10 which may have a diameter of about 1.524 m and a depth of about 1.219 m. The upper end 11 of the carburettor 10 is substantially flat and the base 12 is substantially conical. The wall of the cone is inclined preferably at an angle of 30-45 ° with respect to the horizontal axis of the container. At the top of the conical base there is an opening 13 (preferably about 76.2 to 101.6 mm in temperature) around which a pipe 14 is connected to the tank and connected to a source of positive pressure air. A perforated stainless steel plate 15 is located above the air intake opening extending across the tank and forms a base which supports the fuel layer 16. An astylene flame 17 is inserted through the opening in the carburetor wall to ignite the fuel. According to the drawing, fuel is fed from the hopper 18 through an air barrier 19 and a pipe 20 to form a conical fuel layer 16 on top of the fire layer 21 on the plate 15. With an air flow of about 7080 dm / min and a pressure of 139.7 mm water column and fuel consumption of about 45.3 kg / h, the temperature in the fire layer 21 is about 1650-1920 ° C.

In a device of the size described, the plate 15 can be provided with 6.35 mm holes which are drilled at 12.7 mm center intervals to ensure a substantially even distribution of air through the fuel layer.

An important edge of about 50.8 mm or larger in larger tanks and narrower in smaller ones is left along the edge of the plate 15 so that fuel can accumulate around the fire layer and insulate the carburetor wall from the heat of the fire layer. The pressure in the tank can be kept at 0.07-014 kp / cm or less.

According to the drawing, the fuel mass just above the fire layer is converted to charcoal before it falls into the fire layer and is consumed. On top of the upper end 11 there is a safety valve 20, which 2 reacts to a panel of about 0.35 kp / cm. The hole 23 through which the carburetor 10 enters is made at a flat upper end.

9 67396

In the embodiment shown in the drawing, the fuel is fed from above and acquires a substantially conical shape on top of the fire layer. The gas generated by the combustion of the fuel passes through the fuel bed to the area surrounding the conical bed and through the pipe 24 to the burner 25. The burner 25 can be any device for generating heat by burning a gaseous combustion product obtained when the fuel burns. In one embodiment of the burner suitable for use with the device described above, the burner is surrounded by a jacket having a length of about 60.96 cm and a diameter of about 35.56 cm. The flame generated when the gas burns is deep blue and has a diameter as large as 60.96 cm and a length of 2.13-3.66 m depending on the amount of air introduced into the jacket to create a vortex in the flame. Any commercially available burner designed to burn gas can be used. Using the described vessel under the conditions described, about 5,275,000 kilojoules per hour could be produced for as many hours as air was injected into the fuel bed. The amount of ash generated is negligible. The fuel becomes completely consumed and converted into gaseous products by oxidizing the carbon in the fuel and also converting the other components of the fuel into nitrogenous compounds. Some experiments have found that the gas made by burning the fuel described in my previous patent applications contained about 6% by weight carbon dioxide, about 25% carbon monoxide, about 5% hydrogen probably as water, and about 50% volatile nitrogenous compounds.

Po. the process of the invention can be carried out with already available boilers for generating steam and for use with turbines for generating electricity, simply by connecting the gas outlet of the vessel according to the invention to a suitable burner. In addition, it is contemplated to use the gas obtained by the invention to drive internal combustion engines or other drive machines.

Wood ash usually contains about 50% by weight of calcium, 5-10% by weight of potassium and finally inorganic salts. This ash is consumed in the process of the invention to produce flammable gases by reacting it with nitrogen in the air, and these gases mix with the carbon compounds of the combustion products.

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Although the invention has been described in detail to illustrate it, it is to be understood that this has been done for this purpose only and that changes may be made by those skilled in the art within the scope and spirit of the invention as defined in the claims.

Claims (7)

A process for producing a combustible gas, characterized in that it comprises the support of a mass of freely flowing fuel balls containing pressed organic fiber waste in a furnace on a perforated grid, the flow of air eaten through the grid and through the resulting mass of supported fuel beads, the maintenance of a heat insulating layer of beads in the mass above the burning beads, the ignition of the fuel beads near the grid, and the burning of the heat insulated beads while the air flows through at such a rate that the temperature at which the fuel beads are C and beads just above the burning beads are charred to charcoal beads, and every alkali metal and other non-combustible matter! in the fuel beads, usually removed from the bottom of the furnace as ash, instead reacts with elements in the air to form a combustible gas mixed with other combustible gases formed by oxidation of koi in the fuel and removed with said other combustible gases from the upper end of the furnace to contribute tili heat generated when said combustible gases are burned and raises kJ amount over that generated when only said other gases are burned. 2. A process according to claim 1, characterized in that the fuel is gasified substantially completely into gaseous products. 3. A process according to claim 2, characterized in that the gaseous combustion products contain chemical reaction products of nitrogen with an alkali metal, reaction products of nitrogen and calcium, or mixtures thereof. Process according to claim 3, characterized in that the alkali metal is potassium. 5. A process for producing a combustible gas, characterized in that it comprises supporting a mass of freely flowing fuel balls containing pressed organic fiber material in a substantially enclosed space, the combustion of the fuel balls while being equally supported at the same time as air is spread substantially substantially the burning fuel, and an insulating layer of beads is maintained above the fuel to reach a temperature of at least about 1480 ° C in the burning mass at which temperature the fuel becomes