JP6344691B2 - Gas generator for solid carbon fuel, and unit for generating and burning gas, including gasifier - Google Patents

Description

  The present invention relates to a gasifier for gasifying solid carbon fuel, for example, solid biomass.

  More particularly, the present invention comprises at least one first vertical container comprising supply means for introducing fuel along a first vertical axis therein at the top of the first container and the fuel. A pyrolysis zone in which the pyrolysis is pyrolyzed, a combustion zone for burning pyrolysis gas from the pyrolysis zone, a reduction zone for gasifying the carbonized fuel from the pyrolysis zone, and a gas generated in the reduction zone The gasifier further includes a horizontal plate having an outlet, and wherein the first container receives and holds the fuel supplied in the container, which is fixed between the supply means and the thermal decomposition region.

  The invention also relates to a gas generation and combustion unit comprising a gasifier as described above for generating the gas.

  Gasifiers such as those described above are well known and may be used from solid carbon fuels, in particular from wood chips such as those obtained from sawmills or logging operations, or from agricultural by-products (such as firewood), or others It makes it possible to produce fuel gas from recycled wood. This fuel gas contains, in particular, carbon monoxide and hydrogen, and can then be used for various purposes, for example, fuel for gas turbines, internal combustion engines, boilers or furnaces.

  It is known to provide a fuel supply means for supplying fuel to the first container so as not to permeate the gas that will be generated in the container. This hermeticity prevents the gas produced in the container from entering the fuel storage and supply system, so that during operation of the gasifier, the gas essentially moves towards the outlet. It is known to use a locking mechanism at the inlet of the first container for this purpose.

  International Patent Application No. 2007/081296 discloses a gasifier including a rotary valve located in the upper part of the reactor. This device offers the advantage that the fuel supply can be metered properly, but this requires a separate sealing mechanism upstream due to insufficient gas impermeability, which leads to high costs. There are certainly drawbacks. Furthermore, the valve must be able to withstand the typical high temperatures in the first vessel when the gasifier is operating, thereby requiring a particularly expensive valve.

  As another mechanism, there is a mechanism in which only a double flap gate valve is employed instead of the rotary valve as described above. In addition to the fact that this type of mechanism is less efficient in terms of material weighing (batch weighing), the lower flaps must also be able to withstand the aforementioned high temperatures and are therefore expensive.

  International Patent Application No. 2001/051591 is arranged transversely to the upper part of the reactor, which can be connected between the lock and the first container with a lock that can provide good gas tightness to the gas. And a gasification device including a lateral conduit with a worm screw for properly metering the supply of material. However, such devices are expensive and cumbersome. Worm screws are also prone to soiling and therefore require maintenance and / or are prone to clogging with small pieces of fuel. In addition, if the end of the screw enters the container, it will be exposed to the common high temperatures within the gasifier when it is in operation, necessitating the use of expensive screws.

  International Patent Application No. 2010/109501 discloses a gasifier in the form of a container, into which fuel is introduced laterally. The fuel is then held in the drying area of the container by a horizontal partition having a central hole. A worm screw is installed vertically through this hole to carry fuel from the drying area to the pyrolysis area located directly below the horizontal partition. Because this worm screw enters the pyrolysis zone, it must be able to withstand the typical high temperatures in the gasifier when it is operating, which requires a particularly durable and expensive screw. Become. Worm screws are also prone to soiling, which requires maintenance and / or is clogged with small pieces of fuel.

  One object of the present invention is to at least partially solve the above problems associated with gasifiers.

  For the above purpose, the gasifier according to the present invention comprises a movable pusher in which a first container is mounted between a supply means and a horizontal plate, and the movable pusher is held on the horizontal plate. It is designed to push the existing fuel into the pyrolysis zone and is characterized in that it can be positioned or positioned above the horizontal plate.

  With this arrangement, the horizontal plate forms a thermal screen and protects both the fuel supply means and the pusher from the high temperatures common to the first container (especially from radiation and flame). This makes it possible to use cheaper material transport mechanisms (feeding means, pushers) and / or to improve their durability and / or their reliability.

  This type of movable pusher occupies less vertical space, simpler and more reliable compared to the vertical worm screw (12) proposed in International Patent Publication No. 2010/109501 Is expensive.

  Preferably, the movable pusher includes at least one arm that extends horizontally above the plate and is rotatably mounted about a second vertical axis. The rotating pusher can actually better disperse the fuel on the fuel bed in the pyrolysis zone, thereby improving the quality of the pyrolysis reaction. In particular, as a result, the tar content of the gas produced can be reduced.

  Furthermore, in the past, various mechanisms have been devised to better distribute the fuel supplied to the first container over the fuel bed.

  U.S. Pat. No. 5,755,837 (see FIGS. 4 and 5 thereof) proposes to provide an inclined passage in the upper part of the first container, for example. However, with this device, more material is deposited at the point of dropping onto the fuel bed. In particular, the height of the upper surface of the fuel is higher at the periphery of the first container than at its central portion. With regard to GB 696682, it proposes to provide a mechanism with two perforated rotating plates in the upper part of the first container. Again, the fuel will preferably be placed opposite the hole. Furthermore, the mechanism is easily soiled and / or clogged with small pieces of fuel.

  In order to address these problems, the gasifier according to the invention is preferably an averaging suitable for at least partially averaging the top surface of the solid fuel layer in the pyrolysis zone. Including means. We therefore provide a mechanism that acts directly on the fuel bed rather than acting on the injection of fuel onto the fuel bed, thus reducing or eliminating the disadvantages of known mechanisms. The averaging means can distribute the fuel much better over the fuel bed in the pyrolysis zone, thereby improving the quality of the pyrolysis reaction.

  According to a preferred embodiment, the averaging means comprises at least one arm extending horizontally at the height of the upper surface of the solid fuel layer in the pyrolysis zone, said at least one arm being a third vertical axis. It is mounted for rotation around C. This is actually a simple, reliable and effective means for more evenly distributing the solid material over the material bed in the pyrolysis zone.

  These and other aspects of the present invention will become apparent in the detailed description of specific embodiments of the present invention with reference to the figures in the drawings.

1 schematically shows a front section of a gasifier according to the invention. 1 schematically shows a front section of a preferred embodiment of a gasifier according to the invention. Fig. 3 schematically shows a cross section of the gasifier of Fig. 2; 1 schematically shows a front cross section of a more preferred embodiment of a gasifier according to the invention. Fig. 3 schematically shows a front sectional view of an even more preferred embodiment of a gasifier according to the present invention. 6 schematically shows a cross section of the gasifier of FIG. 2 schematically shows a front cross section of an even more preferred embodiment of a gasifier according to the invention. 2 schematically shows a cross section of an even more preferred embodiment of a gasifier according to the invention. 2 shows a front cross section of a preferred embodiment of a gasifier according to the invention. 2 shows a cross section of a preferred embodiment of a gasifier according to the invention.

  The figures in the drawings are not to scale. Generally, like elements are denoted by like reference numerals in the drawings.

  Examples of embodiments described later relate to a cocurrent fixed bed gasifier formed by a single vessel including a pyrolysis region, a combustion region, and a reduction region simultaneously. The invention is not limited to this type of gasifier, but includes all gasifiers having the features of the premise of claim 1, for example countercurrent gasifiers or a plurality of consecutive containers, It will be clear that other gasifiers are also involved, such as those in which the vessel undergoes a pyrolysis reaction of the fuel.

  Furthermore, although the example of embodiment mentioned later uses solid biomass as an example of fuel, it is obvious that any other type of solid carbon fuel is suitable.

FIG. 1 schematically shows a front section of a gasifier (1) according to the invention. In this example, this is a cocurrent fixed bed gasifier. This gasifier is basically formed by a reactor in the form of a vertical vessel (4), which is continuously from top to bottom,
An inlet lock (5) for introducing biomass (2) into the container along the first vertical axis (A);
A pyrolysis zone (10) for pyrolyzing the biomass introduced into the container;
A combustion zone (20) for burning pyrolysis gas from the pyrolysis zone;
-A reduction zone (30) for gasifying the carbonized biomass from the pyrolysis zone;
-An outlet (6) for recovering gas from the reduction zone;
-An area (40) for collecting and removing ash;
including.

  It should be noted that the inlet lock can take a variety of forms, such as a rotary valve and / or a double flap gate valve and / or any other introduction means known to those skilled in the art. .

  Biomass (2), for example wood chip, is introduced into the container (4) from above via the inlet lock (5) and then the pyrolysis zone (10) via intermediate devices (50, 51) which will be described in detail later. Where the effects of heat decompose into volatile substances and solid residues with a high carbon content commonly referred to as “char” or “coke”. This reaction generally occurs in the temperature range of 300 ° C to 700 ° C.

  In order to reach this temperature, the container generally comprises a first means of charging the pyrolysis agent (11), which is one or more open laterally, for example at the height of the pyrolysis zone in the container. This allows the introduction of a gas that will directly or indirectly supply the energy necessary to break down the biomass into volatiles and “char”. The pyrolysis agent can be, for example, a reaction gas containing oxygen, which releases the energy necessary for pyrolysis by burning only a portion of the biomass or biomass degradation products. It can also be an inert gas (eg, carbon dioxide, nitrogen, water vapor) that, when preheated, provides the energy necessary for pyrolysis. This can also be a combination of the above two gases.

  The “char” is then transported to the reduction zone (30) by well-known means, such as those described in European Patent Application No. 11171156, for example.

Volatile material (also referred to as “pyrolysis gas”) entering the combustion zone (20) is partially or completely burned therein. In order to facilitate this combustion, the container preferably includes a second means for charging the gasifying agent (21). Such second charging means can include, for example, one or more nozzles that open laterally within the container at the height of the combustion zone. “Gassing agent” shall be understood as a gas capable of reacting with carbon and / or hydrogen contained within a solid fuel. Thus, the gasifying agent can be, for example, ambient air, a gas with a higher oxygen concentration, water vapor, carbon dioxide, or a mixture of these gases. This combustion basically generates carbon dioxide (CO ₂ ) and water (H ₂ O), and of course heat. In general, in the combustion region, the temperature can be higher than 1100 ° C. The “char” carried to the reduction zone reacts with the combustion products to produce, in particular, carbon monoxide (CO) and hydrogen (H ₂ ).

For example, in the case of a lignocellulosic material such as wood, a self-heat exchange reaction, and when ambient air at ambient temperature is used as the gasifying agent, this reaction generally occurs in the temperature range of 300 ° C to 800 ° C. However, when using higher carbon fuels and / or with preheated reagents, this temperature is higher and can reach 1300 ° C. or sometimes exceed it. The gas produced by this reaction is recovered at the outlet (6) of the reactor arranged at the bottom of the container (4). In Therefore outlet (6), when using ambient air as a gasifying agent, typically about 15% to 30% of CO, 10% to 25% of _H 2, 0.5 to 3% of _CH 4, 5 % to 15% of _CO 2, 49% of the combustion gas containing _{N 2} is obtained. Ashes can be recovered at the bottom (40) of the container.

  Such gasifiers are known and therefore their design or operation is not described in further detail.

  Attention is now drawn to the device (50, 51) located directly under the inlet lock (5).

  This device, on the other hand, includes a horizontal plate (50) mounted and secured between the inlet lock (5) and the pyrolysis zone (10). The plate (50) is sized and positioned to receive and at least partially hold fuel (2) introduced into the container (4) via the inlet lock (5).

  Preferably, the plate is sized and positioned so that it retains all of the fuel and the latter flows only to the pyrolysis region under the action of an external action, such as the pusher described below.

  For this purpose, the position and size of the plates are adjusted according to the characteristics of the fuel flow used, in particular their inclination angle (for example, in the case of wood pieces, the inclination angle is around 60 °).

  The device further includes a movable pusher (51) mounted between the inlet lock (5) and the horizontal plate (50). The pusher (51) is positioned above the horizontal plate (50), whereby the horizontal plate forms a thermal screen that protects the pusher from heat spreading below the plate when the gasifier is operating. As shown in the figure, this can be, for example, a horizontal jack, with a vertical plate attached to its end and functioning as a pusher. When the jack is operated, the fuel held on the plate is pushed by the vertical plate and falls into the pyrolysis region (10) by gravity. Fuel metering can be achieved by controlling the movement of the jack.

  FIG. 2 schematically shows a front section of a preferred embodiment of gasification according to the invention. According to this preferred embodiment, the movable pusher (51) extends horizontally above the horizontal plate (10) and is at least one mounted rotatably about a second vertical axis (B). Including an arm (52). This arm can consist, for example, of a vertical plate.

  Here, one end of the arm is connected to a shaft of a motor (M) for rotating the arm. The movable pushers (51, 52) can therefore be positioned above the horizontal plate (50), so that the plate acts as its thermal screen when the pusher is effectively positioned above the plate. Can fulfill. The pusher may temporarily protrude beyond the plate when the motor (M) is started, but it is important to note that the pusher can be positioned above the plate at any point in time. Is understood.

  Preferably, the motor (M) is provided with a reduction gear for increasing the torque and accuracy of the motion transmitted to the first arm. Preferably, the motor (M) is positioned above the plate so that the plate also forms a thermal screen for the motor. More preferably, the motor (M) is mounted outside the container, in which case its shaft passes through the upper part of the container via a seal or seal bearing and is then connected to the first arm (which is Not shown).

  Preferably, the second axis (B) is offset from the first axis (A).

  FIG. 3 schematically shows a cross section of the gasifier of FIG. This shows an example of possible configurations of the horizontal plate (50) and pusher arm (52) and how these two elements can be arranged relative to each other.

  Preferably, the gasifier controls the motor (M) by driving at least one arm (52) of the pusher so as to rotate around the second axis (B) and controlling the motor (M). First control means (60) suitable for rocking said at least one arm (52) about a second axis (B). For this purpose, it is possible to use, for example, a motor which can reverse the direction of rotation, for example a direct current motor.

  Thus, when the motor rotates in the first rotation direction, the biomass overflows from the first end (56) of the plate, and when the motor rotates in the second rotation direction opposite to the first rotation direction, It is possible to overflow from the second end (57) of the plate opposite to the one side. As a result, the fuel can be more evenly distributed on the floor in the pyrolysis region.

  Preferably, the first control means (60) can set the initial angular position (P1) and amplitude (A1) of the peristalsis, thereby more accurately controlling the transfer of biomass from the plate to the pyrolysis region. it can. For this purpose, it is possible to use, for example, a stepping motor with an encoder wheel for the angular position of the motor shaft and a suitable controller, such assemblies are well known per se.

  FIG. 4 schematically shows a front section of a more preferred embodiment of the gasifier according to the invention.

  Here, the first vessel (4) further comprises averaging means (70) suitable for at least partially averaging the upper surface (80) of the biomass layer in the pyrolysis zone (10). As shown in the figure, these averaging means include, for example, a horizontal jack, which is provided with a scraper at its end. The scraper is arranged at the height of the upper surface (80) of the biomass layer in the pyrolysis region (10). Preferably, the scraper is in the form of a rake having downward teeth. Therefore, the upper surface (80) of the biomass layer can be averaged by operating the jack.

  FIG. 5 schematically shows a front section of an even more preferred embodiment of the gasifier according to the invention. According to this more preferred aspect, the averaging means (70) comprises at least one averaging arm (71) extending horizontally at the height of the upper surface (80) of the solid fuel layer in the pyrolysis region (10). The at least one averaging arm (71) is rotatably mounted about a third vertical axis (C). The averaging arm can be composed of a vertical plate or a rake with downward teeth, for example.

  Here, one end of the averaging arm (71) is connected to a shaft of a motor (M) that rotates the arm (71). Preferably, the motor (M) is provided with a reduction gear for increasing the torque and accuracy of the motion transmitted to the arm (71). Therefore, the operation of the motor makes it possible to average the upper surface (80) of the biomass layer when the gasifier is operating.

  FIG. 6 schematically shows a cross section of the gasifier of FIG. This gives a better understanding of the averaging arm (71) and its rotational movement.

  Preferably, the averaging means includes six arms mounted radially at 60 degree intervals around a rotating shaft having axis C.

  Preferably, axis B and axis C coincide. More preferably, the at least one arm (52) of the pusher and the at least one arm (71) of the averaging means are attached to the same rotating shaft (75). An example embodiment is shown in FIGS. 7a and 7b. Here, one motor (M3) drives the pusher arm (52) and the averaging arm (71) simultaneously via a common axis of rotation (75), which simplifies assembly and therefore It is cheaper, smaller, and more reliable.

  In such a configuration, the pusher arm (52) and the averaging arm (71) are preferably mounted on opposite sides, i.e. offset by an angle of 180 degrees, which can be seen more clearly from Fig. 7b. When the common motor (M3) is actuated and the arms (52) and (71) are oscillated, this causes the pusher arm (52) to move onto the biomass layer (80) during each forward or return movement. The arm (71) always passes over the biomass that has already been injected. As a result, the surface of the biomass layer in the pyrolysis zone is better averaged, thereby improving the pyrolysis reaction.

  Figures 8a and 8b show a front cross-section and a cross-section, respectively, of a preferred embodiment of the gasifier according to the invention. Here, the plate is formed by a fixed plate (50) extending over substantially the entire cross section of the container (4). The plate (50) is further provided with at least one opening (58), through which the pusher (52) can push the fuel (2) held by the plate, so that the fuel is pulled by gravity. It falls into the pyrolysis zone (10). Since the opening (58) is offset with respect to the charging means (5), fuel cannot fall directly into the pyrolysis region. Except for this point, the gasifier is the same as described above.

  As shown in FIG. 8a, the motor (M3) is preferably moved out of the container (4) so that it can be easily accessed and subjected to general conditions (temperature, presence of gas, etc.) within the container. Not exposed.

  The plate and the pusher can hold the fuel supplied by the supply means (5), and the fuel held by the pusher (52) can be pushed and dropped into the pyrolysis region (10) by gravity. Many other forms are possible, if any.

  The invention also relates to a gas generation and combustion unit comprising a gasifier as claimed in any of the above-mentioned claims for producing said gas. For example, this can be an assembly comprising the gasifier described above and an internal combustion engine, with the gasifier outlet (6) being connected to the fuel injection system of the internal combustion engine.

  Although the present invention has been described with reference to specific embodiments, this has been presented for purposes of illustration only and should not be construed as limiting. In general, it will be apparent to those skilled in the art that the present invention is not limited to the examples shown in the drawings and / or described above. The present invention includes each of the novel features and any combination thereof.

  The reference numbers in the drawings should not be considered limiting, including the case where these numbers appear in the claims.

  Use of the verb “comprise, include, cont” and other variations, and conjugations thereof, does not exclude the presence of elements other than those explicitly stated.

  The use of the indefinite article (a) or definite article (the) to introduce an element does not exclude the presence of a plurality of these elements.

  In summary, the present invention can also be described as follows. That is, a solid comprising at least one first vertical container (4) and supply means (5) for introducing fuel (2) into the upper part of the first container above the pyrolysis region (10). A gasification apparatus for carbon fuel (2), wherein the pyrolysis region is a region for pyrolyzing the introduced fuel to generate pyrolysis gas and carbonized fuel. The gasifier also includes a combustion region (20) for burning the pyrolysis gas, a reduction region (30) for gasifying the carbonized fuel from the pyrolysis region (10) to generate synthesis gas and ash, And a discharge port (6) for collecting the synthesis gas. The first container (4) is mounted between the supply means (5) and the pyrolysis region (10), and a fixed horizontal plate (50) for holding the introduced fuel therein, and the supply means (5) and a movable pusher (51) mounted between the plate (50) and transporting the fuel held on the plate to the pyrolysis region (10). The plate (50) at least partially protects the supply means (5) and the movable pusher (51) in the first container (4) from the common high temperatures when it is operating. To form a thermal screen.

Claims (5)

In a gasification apparatus (1) for gasifying a solid carbon fuel (2), at least one first vertical container (4), wherein the fuel (2) is converted into the first vertical container ( 4) a supply means (5) for introducing along the first vertical axis (A) at the top of 4), in which a pyrolysis region (10) for pyrolyzing the fuel, and the pyrolysis region (10) A combustion region (20) for burning the pyrolysis gas from the gas, a reduction region (30) for gasifying the carbonized fuel from the pyrolysis region (10), and an outlet for recovering the gas generated in the reduction region (6) at least one first vertical container (4), wherein the first vertical container (4) is interposed between the supply means (5) and the pyrolysis region (10). A horizontal plate attached and receiving and holding the fuel (2) introduced into the first vertical container (4) Including a 50),
The first vertical container (4) includes a movable pusher (51) attached between the supply means (5) and the horizontal plate (50), and the movable pusher (51) , Designed to push the fuel held on the horizontal plate into the pyrolysis region, positioned or positioned above the horizontal plate (50),
Said first vertical vessel (4) comprises averaging means (70) suitable for at least partially averaging the upper surface (80) of the solid fuel layer in said pyrolysis zone (10);
The movable pusher (51) includes at least one arm (52) that extends horizontally above the horizontal plate (10) and is rotatably mounted about a second vertical axis (B). ,
The gasifier (1) drives the motor (M) to rotate the at least one arm (52) of the pusher around the second vertical axis (B), and the motor (M ) And first control means (60) adapted to swing said at least one arm (52) about said second vertical axis (B);
The averaging means (70) includes at least one averaging arm (71) extending horizontally at the height of the upper surface (80) of the solid fuel layer in the pyrolysis region (10), the at least one Two arms (71) are mounted for rotation about a third vertical axis (C),
The second vertical axis (B) and the third vertical axis (C) coincide,
The gasifier, wherein the at least one arm (52) of the pusher and the at least one arm (71) of the averaging means are attached to the same rotating shaft (75) . Characterized in that said second vertical axis (B) is shifted to the first vertical axis (A), the gasifier of claim 1. It said first control means (60), characterized in that it set the initial angular position (P1) and amplitude (A1) of the swing, the gasifier of claim 1. Said averaging means, characterized in that it comprises the third six arms mounted radially at 60 degree intervals around the rotary shaft having a vertical axis (C), the gas according to claim 1 Device. To generate a gas, a unit for burning, the unit comprising a gasifier according to any one of claims 1 to 4 for generating the gas.

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