• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a biomass gasification stave (BGS) based on top lit updraft (TLUD) gasification technology. The BGS uses solid fuel in form of pellets or similarly shaped material and converts the solid fuel into a synthesis gas (syngas) including carbon monoxide, hydrogen and methane. The syngas is both produced and burned in the stove and during burning, the syngas is mixed with a flow of secondary air providing a very clean and effective burning. The invention relates to a gasification equipment converting solid fuel into syngas during operation, the equipment comprises: - a reactor comprising a reactor chamber (15) configured to hold a column of solid fuel for gasification during operation, the reactor chamber comprises a gas inlet for primary air at the lower end of the reactor chamber and a gas outlet for produced syngas at the top of the reactor chamber; and -a burner part (9) placed at the top of the reactor (15) which burner part (9) comprises an inlet for syngas and a top burner (13) where produced syngas is combusted during operation. Further, the burner part (9) comprises a mixing chamber which mixing chamber comprises the inlet for syngas and further comprises an inlet for secondary air and an outlet for the gas mixture allowing the gas mixture to reach the top burner (13).
    公开号:DK201870209A1
    申请号:DKP201870209
    申请日:2018-04-09
    公开日:2019-10-30
    发明作者:Nguyen Minh Hai；Hong Nguyen Long
    申请人:Energitek ApS；
    IPC主号:
    专利说明:

    Biomass gas stove
    The present invention relates to a biomass gasification stove (BGS) based on top lit updraft (TLUD) gasification technology. The BGS uses solid fuel in form of pellets or similarly shaped material and converts the solid fuel into a synthesis gas (syngas) including carbon monoxide, hydrogen and methane. The syngas is both produced and burned in the stove and during burning, the syngas is mixed with a flow of secondary air providing a very clean and effective burning.
    Background Art:
    The gasification technology has been known since the 17th century. However, due to intensive exploitation of fossil fuels, especially the handy and cheap oil, the gasification technology sunk into oblivion for a long period. At the turn of the 21st century, a greater of awareness of effect of use of fossil fuels on climate change and global warming, together with the political instability in oil-producing countries has created a momentum for gasification technology to raise once again as a sustainable energy source. Looking for a replacement for fossil fuels, biomass gasification technology is a natural choice as biomass is a renewable fuel, it is carbon neutral, can be converted into gas and then used efficiently.
    Biomass gasification technology comprises a thermal conversion of organic materials at high temperature with partial oxidation. The main product of biomass gasification is a combustible syngas, including hydrogen, carbon monoxide and methane as main components.
    Gasification is a technology that can convert solid waste into a high-quality energy source. After production, the syngas may be burned completely when sufficient air is supplied at an appropriate temperature without producing any by products or polluting substances.
    However, two factors must be mastered to ensure that high performance is achieved during a gasification process: (1) creating optimal conditions during the gasification to create more gas with of a high quality (H2, CO, short circuit hydrocarbons); (2) creating optimal conditions during burning of the obtained syngas producing a high temperature during burning and consequently a clean exhaust gas.
    Disclosure of the Invention
    The BGS converts low level fuel, such as solid fuel into higher level fuel (syngas) for a better experience. Using syngas provides a clean, adjustable and tar-free burning which is easier and more comfortable for users than cookstoves using solid fuel. Moreover, fuel cost for the stove is low because of a very high thermal efficiency of the BGS. Although, the equipment is called a “BGS”, it may be used for other solid fuels than biomass, e.g. coal, the equipment is however very suitable for biomass as it reduces the amount of tar in the produced syngas.
    According to a first aspect, the invention relates to a gasification equipment converting solid fuel into syngas during operation, the equipment comprises:
    - a reactor comprising a reactor chamber configured to hold a column of solid fuel for gasification during operation, the reactor chamber comprises a gas inlet for primary air at the
    DK 2018 70209 A1 lower end of the reactor chamber and a gas outlet for produced syngas at the top of the reactor chamber;
    - a burner part placed at the top of the reactor which burner part comprises an inlet for syngas and a burner where produced syngas is combusted during operation;
    wherein the burner part comprises a mixing chamber which mixing chamber comprises the inlet for syngas and further comprises an inlet for secondary air and an outlet for the gas mixture allowing the gas mixture to reach the burner.
    The effect of providing the equipment with a mixing chamber is that when having separated flows of primary air and secondary air, it is possible to optimize both the production of syngas and the burning of the syngas, thereby providing a more efficient process when converting solid fuel to heat energy.
    The burner at the top basically has three functions: First, the burner may reduce the speed of the mixing gases, i.e. syngas and air, e.g. by forcing the gasses through a twisted valve with high speed, reducing the speed of flame so that the gases are completely burnt. Second, the burner gets very hot when burning, and the heated burner creates a thermal inertia keeping the flame stable even during windy conditions. Thirdly, the burner may spread the flame uniformly as a traditional gas burner.
    According to an embodiment of the gasification equipment, the mixing chamber may comprise means for circulating or otherwise increase turbulence of the gas mixture to improve mixing, e.g. by shaping the mixing chamber as a cone or otherwise reduce the cross-section of the mixing chamber in the flow direction, or provide the mixing chamber with internal walls increasing travel length or direction of the gas flow inside the mixing chamber.
    It may be advantageous to obtain a cyclonic mixing of syngas and secondary air before burning the syngas in the top burner. If the syngas (from forced primary air) and preheat secondary air meet each other at very high speed, then the syngas may have difficulties catching fire. Guiding both lines of air through a twisted valve inside the burner will create a cyclonic mixing of syngas and added air providing a complete burning of gas. The result will increase the thermal efficiency and create a cleaner exhaust gas.
    According to any embodiment of the gasification equipment, the reactor may comprise a top cap defining an upper end or closure of the reactor chamber, which top cap comprises an opening defining the outlet for syngas from the reactor which opening has reduced cross-section compared with the open top of the reactor chamber.
    According to any embodiment of the gasification equipment, the equipment further comprises an insulation layer constituted of an air flow, a liquid or a solid isolating material such as rockwool or the like positioned around the outer surfaces of the reactor chamber, e.g. between an inner and outer cover.
    DK 2018 70209 A1
    To obtain an optimal syngas quality, it is important to keep the temperature in the reactor high, preferably as high as 800°C. An insulated layer not only helps to maintain the high temperature of the reactor, it also keeps the cover of the equipment cool from the very hot environment inside it. According to any embodiment of the gasification equipment, a pathway for secondary air may be provided along an outer wall or surface of the reaction chamber at least along a part of the height of the reaction chamber causing preheating of the secondary air.
    When operating a gasification equipment according to the invention, secondary air may be forced around an outer surface of the reactor chamber and heated before mixing with the syngas preventing cooling of the syngas and creation of tar.
    According to any embodiment of the gasification equipment, pressure means such as a fan may provide an increased pressure at the gas inlet for primary air during operation. The same pressure means, or different pressure means, may provide an increased pressure at the gas inlet for secondary air.
    According to any embodiment of the gasification equipment, pressure means such as a fan may provide an increased pressure at the gas inlets for both primary and secondary air during operation.
    According to any embodiment of the gasification equipment, the equipment further may comprise an air tube and a wind box, the air tube having an inlet for pressurized air and an outlet for pressurized air and the wind box being positioned below or at a lower end of the reactor chamber and having an inlet for an air flow and a distributor part configured to distribute primary air into the reactor chamber, the air tube is configured to guide the air flow to the wind box.
    According to any embodiment of the gasification equipment, the air tube may be configured to divide the air flow into a flow of primary air and a flow of secondary air, the flow of primary is directed to the inlet of the wind box and the flow of secondary air is directed to a pathway configured to guide the secondary air from the outlet of the air tube to the mixing chamber.
    The flame power i.e. the energy developed during burning, may be controlled by controlling the ratio between primary and secondary air, and by controlling the power input to the pressure means or to each pressure means.
    According to any embodiment of the gasification equipment, the equipment may further comprise an adjustment bar connected to the air tube and configured to control the air flow i.e. the amount of air, flowing through the air tube.
    According to any embodiment of the gasification equipment, the reactor chamber may comprise a gasification section (40) and a solid discharge section (41), the gasification section extends vertically inside the reaction chamber and is configured with at least partly vertical walls holding or restricting the column of solid fuel and char, the upper edge of the walls of the gasification section is distanced from the inner surfaces of the reaction chamber thereby providing an open space above the gasification section, the solid discharge section extends at least partly parallel to
    DK 2018 70209 A1 the gasification section,), and/or optionally beyond the gasification section(40), and is configured to receive char and ash discharged from the gasification section.
    According to any embodiment of the gasification equipment, the solid discharge section may surround the gasification section at the upper edge of the - at least partly vertical - walls of the gasification section being configured to allow char and ash to be discharged from the gasification section into the solid discharge section.
    According to any embodiment of the gasification equipment, the solid discharge section may comprise at least one ash chamber at the bottom of the solid discharge section, optionally a second ash chamber may be positioned below the first ash chamber, each ash chamber is configured with an ash outlet through which ash outlet char and ash may be removed from the ash chamber(s) either continuously or in portions i.e. as batches.
    According to any embodiment of the gasification equipment, the gasification section may comprise a fuel tube where a first part of the fuel tube comprises an approximately horizontal tube or pipe entering into the reaction chamber (15) through an opening in a side part or approximately vertical wall of the reaction chamber (15) in an approximately horizontal direction, where an approximately horizontal direction means that a centerline of the fuel tube deviates less than 45°, normally less than 30°, or less than 20°, or less than 10° from horizontal, and a second part of the fuel tube is positioned inside the reaction chamber comprising walls extending in an approximately vertical direction configured to form a column of solid fuel and char in an approximately vertical direction, where an approximately vertical direction means that a centerline of the column of solid fuel deviates less than 45°, normally less than 30°, or less than 20°, or less than 10° from vertical. According to any embodiment comprising such a fuel tube, an inner surface of the fuel tube positioned at the transition of the first approximately horizontal part to the second approximately vertical part may comprise an inclined or rounded surface facing at least partly in the direction of flow of solid fuel and facing at least partly upwards, re-directing the flow of solid fuel from an approximately horizontal direction to an approximately vertical direction.
    According to any embodiment of the gasification equipment, the equipment may comprise a piston shell and a piston head, where a first part of the fuel tube may comprise or is constituted of a piston shell inside which piston shell the piston head is configured to move back and forth between a forward and a retracted position.
    According to any embodiment of the gasification equipment, the piston shell may comprise an inlet for feed i.e. solid fuel, at a position of the piston shell between the forward and the retracted positions of the piston head.
    According to any embodiment of the gasification equipment, the outlet for syngas from reactor chamber is limited to 2-15% of the reactor cross area, preferably to 2-10%, or e.g. to 4-6% of the reactor cross area.
    DK 2018 70209 A1
    According to a second aspect, the invention relates to a method for gasification of a solid fuel comprising the following steps:
    a. positioning a solid fuel e.g. in form of pellets in a reactor chamber where the solid fuel forms a column of solid material;
    b. forcing a flow of primary air into the reactor chamber near the bottom of the reactor chamber;
    c. igniting the solid fuel at the top of the column;
    d. when the temperature in the reaction chamber has raised, the reaction chamber is closed by a burning part (9) or a top cap (14) providing limited access of oxygen, then syngas produced in the reactor chamber is directed into a mixing chamber through an inlet for syngas, and a flow of secondary air is directed to the mixing chamber e.g. by opening a valve;
    e. when operation conditions are reached, i.e. the temperature inside the reaction chamber is at least 700°C, or e.g. at least 750°C, and a layer of char has been formed at the top of the solid fuel column, then the flow of primary air to the reactor chamber and secondary air to the mixing chamber is controlled to obtain a desired intensity of the flame.
    Optimal operating conditions for the biomass gasification are:
    (1) a high temperature inside the reactor, normally at least 700°C, (2) low oxygen content in the reactor chamber which is obtained by controlling primary air and the fuel and char density in the reactor chamber.
    Such optimal conditions result in high performance of thermochemical reactions meaning high efficiency of conversion and production of short chain hydro carbons in the syngas.
    According to any embodiment of the method, the secondary air may be pre-heated to a temperature of at least 100°C, normally at least 200°C, e.g. at least 300°C, before entering the mixing chamber during operation.
    According to any embodiment of the method, the flow of primary air into the reactor chamber may be adjusted to obtain a temperature of at least 700°C, e.g. at least 800°C, in the gasification zone of the reactor chamber.
    Definitions
    Air - when the word “air” is used in the text, the word refers to a gas containing oxygen, and normally the gas will comprise at least 20% oxygen and 80% of other components.
    Biomass - in the context of the present document, the word biomass refers to a solid fuel mainly constituted of carbon, such as wood, coal or the like.
    A column of solid fuel - this expression defines that the solid fuel is packed as a mass or volume extending in a vertical direction. Also, the packed mass/volume will normally extend further in
    DK 2018 70209 A1 the height than in any horizontal cross-section. As the mass/volume extends in a vertical direction, gravity will support packing of the solid fuel.
    Brief Description of the Drawings
    Preferred embodiments of the invention are illustrated in the accompanying figures, in which:
    Figure 1 shows a perspective view of a first embodiment of a stove with batch feeding (BGS) Figure 2 shows a top view of the embodiment of a stove of fig. 1
    Figure 3 shows a side view of the first embodiment of fig. 1 seen from the side opposite the inlet for primary air
    Figure 4 shows perspective view of second embodiment of a biomass gasification stove having continuous feeding of biomass (CBGS)
    Detailed description of the Invention
    A first embodiment of a biomass gasification stove (BGS) according to the invention is shown in fig. 1. The embodiment comprises an outer cover 5 which may be constructed of a thin metal plate such as steel shaped as a cylinder, an inner cover 7 e.g. constructed of a thin metal plate such as steel and also shaped as a cylinder like the outer cover 5, and between the two covers 5 and 7 is a heat-insulating layer 6. The two covers 5 and 7 and the heat insulating layer 6 are connected by top flange connection 8 and bottom flange connection 16, providing a heat insulating cover for the BGS, which helps keeping the temperature inside the stove high during operation, preferably the temperature should be kept above 800°C for optimizing the thermochemical reactions. At a temperature above 800°C, a produced syngas will comprise short chain hydrocarbon, hydrogen and carbon monoxide, which components are easy to bum and has high energy content.
    The embodiment further comprises a reactor chamber 15 provided with a grate 17 fixed at the bottom and supporting biomass inside the reactor chamber 15. The grate 17 has the same shape as the lower end of the reactor chamber 15, which according to this embodiment is a round plate. The grate 17 has openings providing an open cross-section which prevents the fuel from falling through the grate while allowing a flow of primary air into the reactor chamber 15. If the fuel comprises fuel pellets, then the cross-section of the openings is smaller than the minimum diameter of the fuel pellets.
    Also, a device according to the invention may comprise a support part 18 allowing the device to balance properly on the ground.
    The top of the reactor chamber 15 is capped by a reactor cap 14. The reactor cap 14 may be made of material such as cast iron or a material having similar characteristics which may resist heat deformation during operation. A small syngas outlet in the reactor cap 14 directs generated
    DK 2018 70209 A1 syngas to a burner part 9. The reactor chamber 15 is placed on top of a wind box 3 which wind box 3 provides for distribution of gas flowing into the reactor chamber 15.
    The BGS may comprise a pathway 19 for secondary air to the burner part 9 which path way may be placed between the inner cover 7 and the reactor chamber 15. In the shown embodiment, the pathway 19 is formed as an annular space, however, the pathway may also be shaped as a series of pathways 19 e.g. a series of tubes or the like placed around the reactor chamber 15. During operation, the reactor chamber 15 becomes very hot and as the outer surface of the reactor chamber 15 is in contact with the secondary air during the secondary airs travel along the outer surface of the reactor chamber 15, the secondary air is heated before being mixed with the produced syngas. This feature is believed to contribute significantly to increasing and controlling the temperature during burning of the syngas. The pathway(s) 19 has an inlet for air close to the lowest part of the reactor chamber 15, and the pathway(s) 19 may be fed with secondary air from at least one compartment 22 surrounding the wind box 3. The compartment 22 may be a single compartment allowing secondary air to be fed to the pathway(s) 19 all around the outer periphery of the reactor chamber 15.
    The BGS further comprises pressure means 1 configured to force air into and through an air tube
    2. The pressure means 1 may comprise a fan, e.g. a DC fan, or similar. The pressure means 1 may be connected to the air tube 2 by a heat-insulating connector 23 to protect the pressure means 1 from the high temperature in the reactor chamber 15. The air tube 2 extends into the wind box 3 and comprises an air inlet 21 and an air outlet 20, the air outlet 20 comprises one or more openings extending in the longitudinal direction of the air tube 2 or comprises a series of smaller openings, e.g. circular or nearly circular openings or rectangular openings, placed at different positions in the longitudinal direction of the air tube 2.
    The embodiment shown in fig. I comprises an air outlet 20 shaped as a single opening extending in the longitudinal direction of the air tube 2. The air outlet opening shown in fig. 1 has straight side parts extending in the longitudinal direction of the air tube 2, and circular end parts extending in a direction perpendicular to the longitudinal direction of the air tube 2. The length of the opening, i.e. the dimension in the longitudinal direction of the air tube 2, is around 2-3 times the width of the opening, i.e. the dimension in the direction perpendicular to the longitudinal direction.
    The one air outlet 20 shown in the embodiment shown in fig. 1 is positioned close to the wall defining the limit between the wind box 3 and the secondary air compartment 22. This position of at least one air outlet opening provides the possibility of feeding air to both the wind box 3 and the secondary air compartment 22 by a single air tube 2.
    To vary the amount of air fed respectively to the wind box 3, i.e. primary air, and to the compartment 22, i.e. secondary air, the air tube 2 may be displaced in the longitudinal direction,
    i.e. the air tube 2 may be pushed back and forth across the wall defining the barrier between the compartment 22 for second and the wind box 3.
    DK 2018 70209 A1
    According to the first embodiment, a part of the opening of the air outlet 20 is inside the wind box 3 and provides for primary air to the reactor chamber 15 and another is in the compartment 22 outside the wind box 3 and provides secondary air to the burner part 9. The air tube 2 can slide back and forth relative to the wall of the wind box 3 providing a certain displacement of the air tube 2. The displacement may be limited by an anchor pin on the air tube 2. The displacement of the air tube 2 may be controlled by an adjustment bar 4. Feeding of pressurized air to the wind box 3 is important to provide sufficient air for an optimal gasification process and to produce maximum amount of syngas of optimal quality. Optimization of the applied amount of secondary air will improve the quality of the burning pfocess.
    The burner part 9 is positioned above the reactor chamber 15 and above the reactor cap 14, the burner part 9 comprises a mixing chamber where produced syngas is mixed with secondary air and then burned. The heat obtained at the combustion in the burner part 9 may be utilized to heat devices such as pots or pans placed on a supporter 10. The mixing chamber may be cone-shaped which is advantageous as the cone-shape will concentrate syngas and heated secondary air and lead the mixture into a burner tube 11 through a burner tube inlet. The burner tube 11 may be configured with a twisted valve inside which valve is placed between the burner tube inlet and an outlet of the burner tube 11. A top burner 13 is positioned above the outlet of the burner tube 11. While the gases enter and pass through the mixing chamber and the burner tube 11, a swirling and/or turbulent motion may be created in the gas flow. At the outlet of the burner tube 11, the cross-sectional dimension of the burner tube 11 may be increased causing the velocity of the gas mixture to be reduced as the gas mixture reaches the top burner 13 as the gas mixture may then easier catch fire. Moreover, thermal inertia of the top burner 13 will keep a flame stable even in the wind. The top burner 13 may also spread the flame for cooking purpose like an ordinary gas burner. A top hopper 12 placed around the top burner 13 may help protecting a flame as well as concentrating the fire power.
    In order to operate the embodiment of the BGS shown in fig. 1, the burner part 9 as well as the reactor cap 14 is first removed from their shown positions. The fuel compartment of the reactor chamber 15 is then filled partly or completely with a solid fuel e.g. wood pellets or another biomass material of parts or particles large enough to rest on the grate 17 at the bottom of the reactor chamber 15. The reactor chamber 15 is then placed on top of the wind box 3. Power is applied to the pressure means 1 and the longitudinal displacement of the air tube 2 is adjusted so the opening of the air outlet 20 is placed mainly or fully inside the wind box 3 providing mainly or exclusively primary air. The solid fuel in the reactor chamber 15 is then ignited at the top of the reactor chamber by easily ignitable materials such as alcohol, wax, or paper.
    When the temperature in the reactor compartment starts rising, - this normally happens after about 1 minute - the reactor cap 14 is placed at the position of the top of the reactor chamber 15 and the air flow into the reactor chamber 15 is restricted, this will stop the combustion of material at the top of the reactor chamber 15 and initiate the thermochemical reactions which take place at low oxygen content, and then hot syngas will be generated. After having positioned the burner part 9 on top of the BGS, the BGS can be used e.g. for cooking or the like.
    DK 2018 70209 A1
    The solid material in the reactor chamber i 5 is lit at the top (Top Lit) and then the material is converted downwards through the reactor chamber. I.e. the gasification process works its way from the top to the bottom, while the generated syngas works its way up (updraft) through the hot char which causes the gas to be filtered and cleaned for tar components before meeting and mixing with the secondary air.
    The fire power can be controlled by pulling back the adjustment bar 4 which means that less primary air enters into the reactor chamber 15, resulting in a lower production of syngas and less fire power.
    Another or a further way of controlling the process is to provide a valve at the air inlet for the pressure means 1, this will make it possible to control the air supplied by the pressure means I to the reactor chamber 15.
    The first embodiment shown in fig. 1 is a batch biomass gasification stove. This means that a user needs to dismantle the gasification stove, discharge char from the reactor chamber and refill the reactor chamber with fuel before using it again.
    Fig. 4 discloses a second embodiment of a biomass gasification stove according to the invention this embodiment is a continuous biomass gasification stove (CBGS).
    The CBGS shown in fig. 4 comprises 7 main sections:
    A base section comprising a floor part 29 and support parts 18
    A feeder section comprising a feed container 35, a handle 36 for fuel inlet adjustment and a screw wheel 37 controlling feed inlet. The feeder section delivers solid fuel to the fuel delivering section.
    A fuel delivering section controlling the amount of fuel delivered into the reactor chamber and the amount of char being discharged from the reactor chamber, which section comprises a press handle 30, a rod 32 controlling fuel inlet, a lock 31 for rod 32 controlling fuel inlet, a piston shell 34, a piston head 17 allowing air to pass through, a stopper 33 preventing movement of piston head 17 beyond a certain point
    Air control and distribution comprising pressure means 1 such as a fan or similar, a tube for primary air 3, a tube for secondary air 2 and a pathway for secondary air 19, an adjustment handle 4, a valve 20.
    A burner section comprising a top burner 13, a hopper 12, a device supporter 10, a burner tube 11 and a burner part 9
    A gasification section 40 comprising a reactor cap 14, a reactor chamber 15 which outer boundary is defined by an inner cover 7, a vertical feeding tube 38 providing a column of compacted feed, an outer cover 5 and a partial insulating layer 6
    A char discharge section 41 comprising a first ash chamber 24a, a bottom cap 24b, a second ash chamber 24c, a bottom cap 24d, opening mechanisms 25, 26, 27, 28 for bottom caps
    DK 2018 70209 A1
    To start operation of the shown embodiment of a CBGS, the burner part 9 and the top cap 14 are removed. The feed container 35 is filled with particulate solid fuel and as the feed container 35 is placed above the feeding position gravity will force the solid fuel down towards the screw wheel
    37, which screw wheel 37 prevents the solid fuel from falling any further.
    To fill the vertical feeding tube 38, the lock 31 is released thereby unlocking the rod 32, the lock 31 may be constituted as a friction lock constructed from a thick bar e.g. made of metal with an oval hole. The lock 31 prevents the rod 32 from being pushed back by the pressure of solid fuel. The friction force locks the rod 32 at its position, to release the rod 32, the lock 31 is pushed forward. When the rod 32 is unlocked the rod 32 can be pulled back until the piston head 17 is positioned behind the feed inlet opening below screw wheel 37, e.g. until the piston head 17 meets a stopper 33. The drive handle 36 of the feeder section is then turned or otherwise activated thereby forcing or dropping a portion of solid fuel down into the piston shell 34 in front of the piston head 17.
    To advance the solid fuel into the vertical feeding tube 38 of the reactor chamber 15, the press handle 30 is pulled backwards and then the rod 32, the piston head 17 as well as the solid fuel inside the piston shell 34 are forced towards the vertical feeding tube 38. On the way to the vertical feeding tube 38, the solid fuel may meet an inclined surface, which causes the solid fuel to change direction of movement from horizontal to vertical. Activation of the drive handle 36 and movement of the press handle 30 may be repeated until the solid fuel has filled up the vertical feeding tube 38 from the bottom.
    After having filled the vertical feeding tube 38 with solid fuel, the pressure means 1 are turned on, air flow through the tube 2 for secondary air is stopped as the valve 10 e.g. a butterfly valve is closed using the handle 4, and air then only pass through the tube 3 for primary air. The flow of primary air passes through the piston head 17 and through the compacted solid fuel and into the top of the reactor chamber 15.
    Then the top layer of the solid fuel in the vertical feeding tube 38 is ignited by easily ignitable materials such as alcohol, wax, or paper. When the temperature rises to a suitable high temperature such as above 300°C (happens after about 1 minute), then the top cap 14 is placed back in closed position and the production of hot syngas begins.
    At last, the burner part 9 is placed on top of the reactor chamber 15, the valve 10 is opened allowing secondary air to enter the mixing chamber and then the stove can be used for cooking or like heating purposes.
    As the top layer of the solid fuel is ignited first (Top Lit) where after conversion of solid fuel progresses downward, a layer of hot char is formed at the top of the vertical feeding tube 38. As the generated syngas travels up (updraft) through the hot char, the syngas is filtered so that the content of tar in the produced gas is significantly reduced before the syngas meets and mixes with the secondary air.
    DK 2018 70209 A1
    The solid fuel is fed to the vertical feeding tube 38 from the bottom, while gasification takes place near the top of the vertical feeding tube 38, as gasification moves downward the fresh solid fuel entering the vertical feeding tube 38 pushes the gasification zone upwards making it possible to balance the conversion of solid fuel by gasification against the introduction of new solid fuel, such that the gasification permanently takes place at the upper end of the vertical feeding tube 38. Consequently, char and ash produced in the gasification zone are discharged over the top of the wall of the vertical feeding tube 38, falling into the first ash chamber 24a. Over time, the first ash chamber 24a is filled up with char and ash, and then the bottom cap 24b is opened to let char and ashes drop into the second ash chamber 24c. Afterwards, the bottom cap 24b may be returned to a closed position re-closing first ash chamber 24a. The space between the first and the second ash chambers 24a and 24c may act as a buffer zone separating the syngas in the reaction zone from the outside environment, to effectuate such a separation the bottom caps 24b, 24d of the ash chambers should not be opened at the same time. When the second ash chamber 24c is filled, the bottom cap 24d may be opened discharging char, ashes out of the CBGS. The opening mechanisms for bottom cap 24b and 24d may comprise a rod 26, 28 with a counterbalance 25,27 at one end, the other end connects to a bottom cap 24b, 24d. The weight of the counterbalance 25, 27 keeps the bottom cap 24b, 24d in close position hence seal the ash chamber. To open the ash chamber, the rod 26, 28 should be forced upward.
    The temperature inside the reactor chamber 15 is high and easily maintained, both due to heat insulation of the reaction chamber 15 and due to the stability of the gasification zone.
    As the solid fuel is fed into the vertical feeding tube 38 by pressing, both the fuel density and the char density in the vertical feeding tube 38 are increased, this increases the efficiency of the process as it prevents the formation of air channels both in gasification zone and in the char coal layer inside the vertical feeding tube 38. When the solid fuel is converted due to thermochemical reactions in the vertical feeding tube 38, the solid fuel becomes soft and air channels may be created inside the vertical feeding tube 38 causing an undesirable distribution of oxygen in the layers with too much oxygen in the channels and too little oxygen away from the channels, thereby reducing the efficiency of the process.
    The fire power can be controlled by controlling the air inlet provided by the pressure means 1, i.e. by controlling the valve at the air inlet of a DC fan, as well as controlling the air ratio of primary and secondary air by the controlling the opening of the valve 10.
    A CBSG according to the present invention is a gasification equipment converting solid fuel into gas in the present of a limited amount of air, the equipment works continuously based on the Top Lit Up Draft principle, i.e. a column of solid fuel is lit at the top causing the conversion of the fuel to progress downwards while primary air and produced syngas travel upward.
    When feeding the solid fuel by a piston which piston is moving back and forth, it is possible to supply the solid fuel to the reaction chamber from the bottom or at least from the lower half of the reaction chamber 15, as well as it is possible to push char and ashes completely reacted over the top of the vertical feeding tube 38. Moreover, the press of the piston keeps the density of fuel
    DK 2018 70209 A1 and char inside the vertical feeding tube 38 high which is important to prevent formation of channels and keep the gasification process working properly.
    Discharging char over the top of the vertical feeding tube 38 allows using the Top Lit Up Draft (TLUD) gasification principle in continuous process. The TLUD has its advantages in terms of efficiency, clean and simple structure.
    Adding the open space above the vertical feeding tube 38 creates a zone between the top of the solid material in the vertical feeding tube 38 and the top of the open reactor chamber 15 for dropping char over the top of the wall of the vertical feeding tube 38. The top cap 14 is put on the open space above the vertical feeding tube 38 instead of directly on top of the fuel containing space (as it is in the batch BGS version).
    The presence of two ash chambers creates a buffer zone allowing discharge of char and ashes without leaking syngas to the environment.
    The embodiment disclosed in fig. 4 is a manually controlled continuous biomass gasification stove (CBGS) and as long as solid fuel is supplied to the reaction chamber, the equipment will continue to generate syngas for heating purposes. Alternatively, the feeding of fuel and progress of the fuel fed to the gasification equipment may be automated by applying a motor forcing the feed forward and a controller controlling start/stop and force of the motor thereby completely automating the continuous gasification equipment.
    The feeding section disclosed in the embodiment of fig. 4, is a well-functioning feeding section which in a simple way provide a continuous feed of compacted solid fuel to the vertical feeding tube 38 and the reaction chamber 15. However, it would be possible for a skilled person to construct another manual feeding section or an automatically controlled feeding section for the gasification section ofthe CBGS shown in fig. 4 when given the instructions relating to the embodiment of fig. 4 in this document.
    Example 1
    An embodiment of a BGS for burning pellets or granules of solid biomass heating fuels comprises:
    (1) DC fan: designed and made by ourselves. It is a centrifugal fan, with the flow rate about 80 liters of air per minute (1/min) and the pressure about 40 mm H2O. Because of the characteristic of gasification reaction, it need limited air but high pressure. The fan’s properties are calculated based on size of the specific BGS. The fan has a valve to control the air flow by itself.
    The DC fan requires very little power. The DC fan may be powered by a 12-volt battery, by solar panel or by an electric adapter.
    (2) Air tube 2: The air tube is formed as a cylinder. One end of the air tube is directly connected to the DC fan via an insulated connector 23, the other end is closed by a cap of metal. In the cylindrical body of the air tube 2, there is an air outlet 20. The outlet is positioned around the edge of the wind box 3, a part of the outlet 20 is inside the wind box, and the remaining part is
    DK 2018 70209 A1 outside the wind box 3 providing air to a compartment 22 for secondary air. The air tube 2 can be moved back and forth horizontally by an adjustment bar 4, thereby adjusting the ratio of area of the outlet 20 being inside the wind box 3 and outside wind box 3. The compartment 22 is positioned horizontally around the wind box 3 providing a swirling air flow in the compartment
    22.
    (3) Wind box 3: is shaped as an upright cylinder, bottom end of the wind box 3 is leveled with the bottom of the stove and closed, the top surface of the wind box 3 is open. A thin ring is fixed at the outer surface on top of the wind box to help directing the reactor chamber 15 into position when connecting the reactor chamber 15 with the wind box. There is an opening in the side of the wind box, where the air tube 2 is connected horizontally with the wind box, and the air tube 2 can slide through the opening.
    (4) The air ratio adjustment bar 4: is a metal bar having two connected points. One point is connected to the support part 18 e.g. to one leg of a tripod 18, this point forms a center of rotation when the adjustment bar is moving. The second point is connected to the air tube 2, and when the adjustment bar 4 moves forward or backward, the air tube 2 co-moves. Hence, the air outlet 20 on the air tube 2 moves and adjusts the area of the air outlet 20 being inside the wind box (3).
    (5) The outer cover 5 of the BGS: is a thin metal cylindrical wall, which shapes the appearance of the BGS.
    (6) Insulation layer 6: is made from heat-insulating materials such as rock wool or glass wool.
    The insulating layer 6 is positioned between the outside cover 5 and inside cover 7. The insulating layer supports a high temperature inside the stove increasing efficiency and supports a cold surface of the stove increasing safety.
    (7) The inner cover 7 of the stove: a thin metal cylindrical wall. One side faces the insulation layer, the other side faces the reactor chamber 15 and helps creating an annular secondary air manifold.
    (8) Top flange connection 8: an annular thin metal connecting the outer and inner covers 5 and 7 of the stove and closes the insulation layer at the top.
    (9) Burner part 9: a cone cap placed on top of the BGS, where syngas combustion occurs. The burner part 9 includes some parts on the top burner 13.
    (10). Pot supporter 10: comprises three bending metal rods, connected to form a strong frame to hold pots, pans and the like. The pot supporter 10 is fixed to the burner part 9.
    (11). Burner tube 11: comprises a twisted valve constituted by a twisted metal fixed inside a small tube. The valve creates four spiral air flows when both syngas and secondary air passes into the mixing chamber at high velocity. The swirling and turbulent motion of mixed air resulting in 35 complete burning of syngas in the top burner.
    DK 2018 70209 A1 (12) . Hopper 12: improves the stability of the flame and concentrates the fire power. There is an array of small openings on the hopper, these openings allow natural addition of secondary air if needed.
    (13) . Top burner 13: a small piece of metal with two rings of opening on top of the burner. This part has three functions. Firstly, it reduces the speed of mixing gases (syngas and added air going through the twisted valve with high speed) to the speed of flame so that the gases will be completely burned. Secondly, it is very hot when burning providing a thermal inertia, which inertia keeps the flame stable even in windy conditions. Thirdly, it spreads the flame uniformly as a gas burner.
    (14) . Reactor cap 14: When the reactor chamber is capped, there is only a small outlet opening for the syngas. The ratio of the area of the syngas outlet opening to the area of circle of upper surface of the reactor chamber is from 4-6%, to maintain the condition of a limited oxygen content inside the reactor chamber.
    (15) . Reactor chamber 15: a cylindrical space, provided with a grate at the bottom and a gas outlet at top in which space all the thermochemical reactions occur. Fuel is filled into the reactor chamber from the top.
    (16) . Bottom flange 16: an annular thin metal plate connecting the outer and inner covers 5, 7 of the stove and closes the insulation layer 6 at the bottom.
    (17) . Grate 17: supports the solid fuel inside the reaction chamber 15, a circular metal sheet comprising opening having a diameter or minimum dimension smaller than the diameter or minimum dimension of the solid fuel. The grate 17 is fixed near the bottom of the reactor chamber 15.
    (18) . Support part 18: is shown as a tripod having three legs, the tripod is fixed below the bottom of the BGS and provides a stable base for the stove.
    (19) . Pathway 19 for secondary air: extends between inner cover 7 and the reactor chamber 15 (20) . Air outlet 20 on the air tube 2: comprises one or more openings extending in the longitudinal direction of the air tube 2 (21) . Air inlet 21 of air tube 2: Opening letting air into the air tube 2 (22) . Secondary air compartment 22: is positioned between the wind box 3and the outer cover 5 (23) . A heat-insulating connector 23: is made of heat insulating material and connects the DC fan 1 to the air inlet 21 of the air tube 2
    Example 2
    The present invention (CBGS) for burning a solid fuel such as biomass pellets comprising:
    (1) Pressure means 1: The DC fan is a centrifugal fan, providing a flow rate of about 80 liters of air per minute (l/min) and a pressure of about 40 mm H2O. The gasification reaction is improved
    DK 2018 70209 A1 by subjecting the reactor to limited air and high pressure. The DC fan’s properties are calculated based on size of the specific BGS. The DC fan has a valve to control the air flow through the fan.
    The DC fan requires very little power and may be powered by 12-volt battery, by solar panel or by electric adapter. The DC fan supplies both primary air and secondary air to the stove.
    (3) Primary air tube 3, connects the fan to the piston shell (34) and provides a flow of primary air to the vertical feeding tube 38.
    (2) Secondary air tube 2, connects the fan to the outer shell of the stove (5) and provides a flow of secondary air to the top burner 13.
    (4) Air ratio control handle 4: is used to adjust the opening of the butterfly valve 20.
    (5) Outer cover 5 of the stove: an outermost cylindrical tube providing the surface of the stove. An open space between the inner cover 7 and the outer cover 5 creates a pathway 19 for secondary air. The horizontal part of the feeding tube also passes through the outer cover 5.
    (6) Insulation layer 6: made from heat-insulating materials such as rock wool or glass wool. The insulating layer 6 is positioned between the outer cover 5 and the inner cover 7 at the mid-section of the reaction chamber 15. The insulating layer 6 supports a high temperature inside the stove increasing efficiency and supports a cold surface of the stove increasing safety.
    (7) Inner cover 7: the inner cover 7 is constructed as a cylindrical tube, it is positioned between the reactor chamber 15 and outer shell of the stove 5. The upper part of the inner cover 7 embraces the open space of the reactor chamber 15 above the vertical feeding tube 38, the lower part of the inner cover 7 comprises an inlet for the horizontal part of the feeding tube and below the inlet for the feeding tube the inner cover embraces the discharge section. The inner cover extends to near the base.
    (8) A pair of connecting flanges 8, one flange is fixed to the secondary air tube 2, the other flange is fixed to the outer cover 5 of the stove.
    (9) Burner part 9: is formed as a cut cone and fits in size and shape with the outer cover 5 of the stove. The burner part 9 includes a mixing chamber forming a mixture of syngas and secondary air which mixture is then forced through the burner tube 11 comprising a twisted valve.
    (10) Pot supporter: 3 bending metal rods, connected to be a strong frame to hold pots. Fixed on the burner.
    (11) Twisted valve: a twisted metal fixed inside a small tube on the burner. The valve creates four spiral air arrays when both syngas and secondary air path by with high velocity. There is a swirling and turbulent motion of mixed air resulting a very complete burning of syngas on the top burner.
    (12) . Hopper 12: improves the stability of the flame and concentrates the fire power. There is an array of small openings on the hopper, these openings allow natural addition of secondary air if needed.
    DK 2018 70209 A1 (13) Top burner 13: a small piece of metal with two rings of opening on top of the burner. This part has three functions. Firstly, it reduces the speed of mixing gases (syngas and added air going through the twisted valve with high speed) to the speed of flame so that the gases will be completely burned. Secondly, it is very hot when burning providing a thermal inertia, which inertia keeps the flame stable even in windy conditions. Thirdly, it spreads the flame uniformly as a gas burner.
    (14) Reactor cap 14: is made of iron cast and covers the open space of the reactor chamber 15 above the vertical feeding tube 38, there is only a small outlet opening for the syngas. The ratio of the area of the syngas outlet opening to the area of circle of upper surface of the reactor chamber is from 4-6%, to maintain the condition of a limited oxygen content inside the reactor chamber.
    (15) Reactor chamber 15: is defined as the space limited by the inner cover 7, the reactor cap 14 and the bottom cap 24b of the first ash chamber 24a. The reactor chamber is shaped as a cylindrical tube. The feeding tube which is part of the reactor chamber comprises a horizontal part and a vertical part, between these two parts is an inclined surface connecting the two parts. The inclined surface transfers the movement of the solid fuel from a horizontal direction to a vertical direction. All the thermochemical reactions occur inside the reactor chamber 15. Solid fuel is supplied through the feeding tube from the side entrance to the top.
    (16) Means for fastening feeding section to gasification section: A pair of connecting flanges made of metal, one flange is fixed to the piston shell (34), the other one is fixed with the horizontal part of the feeding tube 38.
    (17) Piston head 17: a circular dish made of metal having a radical cut then twisted. The piston head 17 is fixed to one end of the rod 32. This structure can work as a piston when solid fuel is pushed into the piston shell 34 and allow carry over the solid fuel when rotating and moving back at the same time, just like a screw wheel.
    (18) Support part 18 of base section: Tripod fixed to the outer surface of the inner cover 7 of the stove (20) Butterfly valve 20 defines the flow of secondary air from the fan 1 to the burner part 9 through air tube 2 and is used to adjust the ratio between primary and secondary air.
    (24a) First ash chamber 24a: is formed as an inverted cut cone having the same diameter as the inner cover Ί and the reactor chamber 15, the first ash chamber is fixed to the inner surface of the inner cover Ί and capped i.e. sealed by the bottom cap (24b).
    (24b) Bottom cap 24b: a thick circular disk made of metal, seals the first ash chamber 24a and separates the space containing syngas (upper space) and the space holding char.
    (24c) Second ash chamber 24c: same as the first chamber (24a), the space between the first and second ash chambers creates a buffer space making it possible to discharge char and ash without leaking syngas to environment.
    DK 2018 70209 A1 (24d) Bottom cap 24d: a thick circular disk made of metal, seals the second ash chamber 24c and separates the space containing syngas (upper space) and the space holding char.
    (25) Counterbalance 25 of first balance rod 26: a weight connected to one end of the balance rod 26 (26) First balance rod 26: one end of balance rod 26 is fixed to the counterbalance 25, the other end is connected to the bottom cap 24b and keeps the bottom cap 24b closed when the rod is not operated by a user, hence the first ash chamber 24a is sealed when not operated, to open the bottom cap 24b of the first ash chamber 24a the rod 26 must be lifted up.
    (27) Counterbalance 27 of second balance rod 28: a weight connected to one end of the balance rod 28 (28) Second balance rod 28: one end of balance rod 28 is fixed to the counterbalance 27, the other end is connected to the bottom cap 24d and keeps the bottom cap 24d closed when the rod is not operated by a user, hence the second ash chamber 24c is sealed when not operated, to open the bottom cap 24d of the second ash chamber 24c the rod 28 must be lifted up.
    (29) . Base for stove (29, 18): A steel frame 29 provides a solid base for the CBGS and bars (18) support reaches upward supporting upright parts. The height of the base can be adjusted by adjusting screws keeping the CBGS completely horizontal during operation.
    (30) . Press handle 30 for solid fuel: A mechanic structure made of steel, when pulling the press handle 30, the rod 32 moves forward pushing the fuel toward the vertical feeding tube 38.
    (31) . Moving lock 31: made of steel, when the rod 32 moves forward, the moving lock 31 prevents the rod 32 from being pushed back by the pressure of solid fuel. The moving lock 31 creates a friction force locking the rod 32 at its position. To unlock the rod 32, the moving lock is pushed forward releasing the friction force.
    (32) Rod 32: a steel cylinder, one end is bended as a small handle, the other end is fixed to a piston head 17. The rod 32 and the piston head 17 moves together inside a piston shell 34.
    (33) Stopper 33: A thick circular metal dish, with a small opening in the center allowing the rod to pass through but keeping the end of the piston shell 34 sealed enough to prevent air from the DC fan I from leaking out.
    (34) Piston shell 34: a blank circular cylinder placed horizontally, upper surface is connected to the fuel feeder 35. One end is sealed by the stopper 33 and the other end is fixed to vertical feeding tube 38 by a flange connector 16.
    (35) Feed container 35: a hopper protected with cap holding solid fuel to be supplied to the CBGS. The feed container 35 is connected to the piston shell 34 by a tube through which the solid fuel can pass.
    (36) Handle for feed 36: A one step screw wheel 37 is installed coaxial with the tube through which the solid fuel passes from the feed container 35 to the piston shell 34. When the handle 36 is rotated, the screw wheel 37 is also rotated and solid fuel drops to the piston shell 34.
    DK 2018 70209 A1 (37) Screw wheel for feed 37: traditional design known by a skilled person.
    (38) Vertical feeding tube 38: is the part of the feeding tube which inside the reactor chamber 15 is in a vertical position, the vertical feeding tube 38 is open upwards and provided with a horizontal inlet at the bottom.
    It is contemplated that the use of the invention may involve components having different sizes and shapes as long as the principles as describes above are followed.
    DK 2018 70209 A1
    Reference no.Name of reference1Pressure means such as a fan2Air tube for primary and secondary air or for secondary air3Wind box or tube for primary air4Adjustment bar5Outer cover of reactor chamber6Insulating layer7Inner cover of reactor chamber8Flange connection9Burner part10Supporter for units to be heated such as pots or pans11Burner tube12Top hopper13Top burner14Reactor cap15Reactor chamber16Flange connection17Grate or piston head supporting feed of solid fuel18Floor part of base section19Pathway for secondary air20Air outlet of air tube 2 or valve in air tube21Air inlet of air tube 222Compartment for secondary air23Heat insulating connector24aFirst ash chamber24bBottom cap of first ash chamber24cSecond ash chamber24dBottom cap of second ash chamber25Counter balance for opening mechanism of bottom cap 16b
    DK 2018 70209 A1
    26Rod for opening mechanism of bottom cap 16b27Counter balance for opening mechanism of bottom cap 24b28Rod for opening mechanism of bottom cap 24b29Floor part of base section30Press handle31Movement lock for rod 3232Rod33Stopper34Piston shell35Feed container36Handle for feed37Screw wheel for feed38Vertical feeding tube40Gasification section for CBSG41Discharge section for CBSG
    DK 2018 70209 A1
    权利要求:
    Claims (21)
    [1] 1. Gasification equipment converting solid fuel into syngas during operation, the equipment comprises:
    - a reactor comprising a reactor chamber (15) configured to hold a column of solid fuel for gasification during operation, the reactor chamber comprises a gas inlet for primary air at the lower end of the reactor chamber and a gas outlet for produced syngas at the top of the reactor chamber;
    - a burner part (9) placed at the top of the reactor (15) which burner part (9) comprises an inlet for syngas and a top burner (13) where produced syngas is combusted during operation;
    characterized in that the burner part (9) comprises a mixing chamber which mixing chamber comprises the inlet for syngas and further comprises an inlet for secondary air and an outlet for the gas mixture allowing the gas mixture to reach the top burner (13).
    [2] 2. Gasification equipment according to any previous claims, wherein the mixing chamber comprises means for circulating or otherwise increase turbulence of the gas mixture to improve mixing, e.g. by shaping the mixing chamber as a cone or otherwise reduce the cross-section of the mixing chamber in the flow direction, or provide the mixing chamber with internal walls increasing travel length or direction of the gas flow inside the mixing chamber.
    [3] 3. Gasification equipment according to any previous claims, wherein the reactor chamber (15) is configured with a top cap (14) defining an upper end or closure of the reactor chamber, which top cap (14) comprises an opening defining the gas outlet from the reactor chamber (15), which opening has reduced cross-section compared with the open top of the reactor chamber.
    [4] 4. Gasification equipment according to any previous claims, wherein the equipment further comprises an insulation layer (6) constituted of an air flow, a liquid or a solid isolating material such as rockwool or the like positioned around the outer surfaces of the reactor chamber.
    [5] 5. Gasification equipment according to any previous claims, wherein a pathway (19) for secondary air is provided along an outer wall or surface of the reaction chamber (15) at least along a part of the height of the reaction chamber causing preheating of the secondary air.
    [6] 6. Gasification equipment according to any previous claims, wherein pressure means (1) such as a fan provides an increased pressure at the gas inlet for primary air during operation.
    DK 2018 70209 A1
    [7] 7. Gasification equipment according to any previous claims, wherein pressure means (1) such as a fan provides an increased pressure at the gas inlet for secondary air during operation.
    [8] 8. Gasification equipment according to any previous claims, wherein pressure means (1) such as a fan provides an increased pressure at the gas inlets for both primary and secondary air during operation.
    [9] 9. Gasification equipment according to any previous claims, wherein the equipment further comprises an air tube (2) and a wind box (3), the air tube (2) has an inlet for pressurized air and an outlet for pressurized air and the wind box (3) is positioned below or at a lower end of the reactor chamber (15) and has an inlet for an air flow and a distributor part configured to distribute air into the reactor chamber, the air tube (2) is configured to guide the air flow to the wind box (3).
    [10] 10. Gasification equipment according to any previous claims, wherein the air flow through the air tube (2) is divided into a flow of primary air and a flow of secondary air flow of primary air entering inlet of the wind box (3) and a flow of secondary air entering a pathway (19) outside the wind box (3), the pathway (19) is configured to guide the secondary air from the outlet of the air tube (2) to the mixing chamber.
    [11] 11. Gasification equipment according to any previous claims, wherein the equipment further comprises an adjustment bar (4) connected to the air tube (2) and controlling the air flow through the air tube (2).
    [12] 12. Gasification equipment according to any previous claims, wherein the reactor chamber (15) comprises a gasification section (40) and a solid discharge section (41), the gasification section (40) extends vertically inside the reaction chamber and is configured with at least partly vertical walls holding a column of solid fuel and char, the upper edge of the walls of the gasification section (40) is distanced from the inner surfaces of the reaction chamber (15) thereby providing an open space above the gasification section (40), the solid discharge section (41) extends at least partly parallel to the gasification section (40), and/or optionally beyond the gasification section(40), and is configured to receive char and ash discharged from the gasification section (40).
    [13] 13. Gasification equipment according to claim 12, wherein the solid discharge section (41) surround the gasification section (40) at the upper edge of the at least partly vertical walls of the
    DK 2018 70209 A1 gasification section (40) allowing char and ash to be discharged from the gasification section (40) into the solid discharge section (41).
    [14] 14. Gasification equipment according to claim 12 or 13, wherein the solid discharge section (41) comprises at least a first ash chamber (24a) at the bottom of the solid discharge section (41), optionally a second ash chamber (24c) is positioned below the first ash chamber (24a), each ash chamber (24a, 24c) is configured with an ash outlet (24b, 24d) through which ash outlet char and ash may be removed from the ash chamber(s) either continuously or in portions.
    [15] 15. Gasification equipment according to anyone of the claims 12-14, wherein the gasification section (40) comprises a fuel tube where a first part of the fuel tube comprises an approximately horizontal tube or pipe entering into the reaction chamber (15) through an opening in a side part or wall of the reaction chamber (15) in an approximately horizontal direction, where an approximately horizontal direction means that a centerline of the fuel tube deviates less than 45°, normally less than 30°, or less than 20°, or less than 10° from horizontal, and a second part of the fuel tube is positioned inside the reaction chamber comprising walls extending in an approximately vertical direction configured to form a column of solid fuel and char in an approximately vertical direction, where an approximately vertical direction means that a centerline of the column of solid fuel deviates less than 45°, normally less than 30°, or less than 20°, or less than 10° from vertical.
    [16] 16. Gasification equipment according to anyone of the claims 12-15, wherein an inner surface of the fuel tube positioned at the transition of the first approximately horizontal part to the second approximately vertical part comprises an inclined or rounded surface facing at least partly in the direction of flow of solid fuel and facing at least partly upwards, re-directing the flow of solid fuel from an approximately horizontal direction to an approximately vertical direction.
    [17] 17. Gasification equipment according to anyone of the claims 12-16, wherein the first part of the fuel tube comprises a piston shell (34) in which shell a piston head (17) is configured to move back and forth between a forward and a retracted position.
    [18] 18. Gasification equipment according to anyone of the claims 12-17, wherein the piston shell (34) comprises an inlet for feed at a position of the piston shell (34) between the forward and the retracted positions of the piston head (17).
    [19] 19. Method for gasification of a solid fuel comprising the following steps:
    DK 2018 70209 A1
    a. positioning a solid fuel e.g. in form of pellets in a reactor chamber where the solid fuel forms a column of solid material;
    b. forcing a flow of primary air into the reactor chamber near the bottom of the reactor chamber;
    c. igniting the solid fuel at the top of the column;
    d. when the temperature in the reaction chamber has raised, the reaction chamber is closed by a burning part (9) or a top cap (14) providing limited access of oxygen, then syngas produced in the reactor chamber is directed into the mixing chamber through an inlet for syngas, and a flow of secondary air is directed to the mixing chamber e.g. by opening a valve;
    e. when operation conditions are reached, i.e. the temperature inside the reaction chamber is at least 700°C, or e.g. at least 750°C, and a layer of char has been formed at the top of the solid fuel column, then the flow of primary air to the reactor chamber and secondary air to the mixing chamber is controlled to obtain a desired intensity of the flame.
    [20] 20. Method for gasification of a solid fuel according to claim 19, wherein the secondary air is pre-heated to a temperature of at least 100°C, normally at least 200°C, e.g. at least 300°C, before entering the mixing chamber during operation.
    [21] 21. Method for gasification of a solid fuel according to any one of claims 19-20, wherein the flow of primary air into the reactor chamber is adjusted to obtain a temperature of at least 800°C in the gasification zone of the reactor chamber.
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    同族专利:
    公开号 | 公开日
    DK180002B1|2020-01-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2019-10-30| PAT| Application published|Effective date: 20191010 |
    2020-01-15| PME| Patent granted|Effective date: 20200115 |
    优先权:
    申请号 | 申请日 | 专利标题
    DKPA201870209A|DK180002B1|2018-04-09|2018-04-09|Biomass gas stove|DKPA201870209A| DK180002B1|2018-04-09|2018-04-09|Biomass gas stove|
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