Multi-section bed gasification device and gasification method thereof

Abstract

The invention relates to a multi-section bed gasification device and a gasification method thereof, the multi-section bed gasification device comprises: a gasification furnace, the gasification furnace comprises a turbulent flow section, an expansion section and a buffer section which are sequentially connected from bottom to top, the diameter of the expansion section is not less than that of the turbulent flow section, and the top of the buffer section is provided with a feed inlet; the connector comprises a connecting section and a conveying section which are connected, and the connecting section is communicated with the buffering section; the gas-solid separator is communicated with the conveying section; and the material returning device is communicated with the gas-solid separator and the expansion section so as to convey the solid material separated by the gas-solid separator back to the expansion section.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrocarbon fuel gasification, and in particular to a multi-stage bed gasification device and a gasification method thereof. Background Art

[0002] Gasification is one of the core technologies for the clean and efficient utilization of hydrocarbon fuels and is the basis for the development of chemical industries such as carbon-based chemicals and carbon-based gas. The fluidized bed gasification technology conducts gasification reactions in a fluidized form, uses solid slag discharge, has advantages such as strong raw material adaptability, environmental friendliness, no generation of wastewater such as tar, phenol water, and black water, large gasification intensity, and low investment, and is suitable as a gas source for industrial gas, small and medium-sized synthetic ammonia, coal-to-methanol, hydrogen and other chemicals.

[0003] In the bottom turbulent zone of the fluidized bed gasification device, the particle concentration is high and evenly distributed, the collision between particles is intense, and the mass and heat transfer efficiency is high, which is very suitable for material dispersion, combustion and gasification reactions; in the upper and middle dilute phase zones, the particle concentration is low and unevenly distributed, there is a significant annular core structure, the gas phase is in the center, and the particles are close to the wall, which is not conducive to material dispersion and gas-solid reactions, resulting in low reaction space utilization rate in the dilute phase zone and high carbon content in fly ash.

[0004] The conventional solid fuel feeding of the fluidized bed gasification device is very mature and operates stably. However, for hydrocarbon fuels with high viscosity, easy to coke when heated, and easy to adhere to the wall (such as oil sludge, plastic solid waste molding materials, etc.), the conventional furnace type structure and feeding position have problems such as coking and wall adhesion at the feeding port, bringing risks of stopping the furnace caused by damage to the air distribution device and slagging in the furnace. Summary of the Invention

[0005] In view of the above analysis, embodiments of the present invention aim to provide a multi-stage bed gasification device and a gasification method thereof to solve at least one of the above problems.

[0006] On the one hand, the present invention provides a multi-stage bed gasification device, including:

[0007] A gasification furnace, including a turbulent section, an expansion section, and a buffer section connected in sequence from bottom to top, the diameter of the expansion section is not less than the diameter of the turbulent section, and a feed port is provided at the top of the buffer section;

[0008] A connector, including a connecting section and a transporting section connected, the connecting section is communicated with the buffer section;

[0009] A gas-solid separator, communicated with the transporting section;

[0010] A return feeder, communicated with the gas-solid separator and the expansion section to return the solid materials separated by the gas-solid separator to the expansion section.

[0011] Further, a first air inlet and a slag discharge port are provided in the turbulent flow section;

[0012] The first air inlet is located at the bottom end face of the turbulent flow section;

[0013] The slag discharge port is located at the bottom of the side wall of the turbulent flow section.

[0014] Further, the expansion section is a connecting section between the dense phase zone and the transition zone of the gasifier, and a return material port is provided on the side wall of the expansion section, and the return material port is communicated with the return material device.

[0015] Further, the buffer section is the dilute phase zone of the furnace or between the dilute phase zone and the transition zone;

[0016] A connection port is opened on the side wall of the buffer section, and the connection port is connected to the connection section.

[0017] Further, the connection section is a straight pipe that extends obliquely upward from the connection port of the buffer section;

[0018] The center line of the transport section is parallel to the center line of the gasifier, and the transport section expands along the gas flow direction;

[0019] The transport section is provided with a second air inlet, and secondary air enters the transport section through the second air inlet.

[0020] Further, the transport section is provided with a plurality of second air inlets, and an air inlet pipe is provided at each second air inlet;

[0021] The plurality of air inlet pipes introduce secondary air in a tangential circle form.

[0022] Further, the connector includes two connection sections, one ends of the two connection sections are respectively connected to the buffer section, and the other ends of the two connection sections are connected to the bottom of the transport section;

[0023] The transport section is located above the gasifier, and the center line of the transport section coincides with the center line of the gasifier;

[0024] A second air inlet is provided at the connection of the two connection sections and the transport section, and secondary air is sprayed into the transport section in a central jet manner through the second air inlet.

[0025] Further, the connection section is connected to the top of the buffer section;

[0026] The connection section is located above the buffer section, and the transport section is located above the connection end;

[0027] The top of the buffer section is in the shape of a truncated cone, and the inclined side wall of the top of the buffer section is provided with the feed port.

[0028] Further, the lower part of the transport section is in the shape of an inverted truncated cone;

[0029] A plurality of second air inlets are provided at the lower part of the transport section, and an air inlet pipe is provided at each second air inlet;

[0030] The plurality of inlet pipes introduce secondary air in a tangential circle form.

[0031] On the other hand, the present invention provides a gasification method for a multi-stage bed gasification device, which is realized by the above-mentioned multi-stage bed gasification device. The gasification method includes:

[0032] Introduce solid fuel into the gasification furnace through the feed port;

[0033] Introduce the gasifying agent from the first air inlet and the second air inlet;

[0034] Among them, the superficial fluidization velocity of the turbulent section is 2.5 m / s to 6 m / s, the superficial fluidization velocity of the expansion section is 1.5 m / s to 3 m / s, and the superficial fluidization velocity of the buffer section is 0.8 m / s to 2 m / s;

[0035] The superficial fluidization velocity of the connection section is 8 m / s to 15 m / s; the superficial fluidization velocity of the transport section is 5 m / s to 10 m / s;

[0036] The primary air is introduced into the gasification furnace from the first air inlet, the oxygen concentration of the primary air is set to 15% to 45%, and the proportion of the primary air in the total amount of the gasifying agent is 65% to 90%;

[0037] The secondary air is introduced into the connector from the second air inlet, and the oxygen concentration of the secondary air is 21% to 60%; the secondary air is introduced in a uniformly distributed tangential circle manner, and the flow velocity of the secondary air nozzle is 45 m / s to 100 m / s.

[0038] Compared with the prior art, at least one of the beneficial effects that can be achieved by the present invention is: by multi-stage dividing the furnace chamber of the gasification furnace and connecting the gas-solid separator through the connector, the traditional annular core structure in the dilute phase region of the fluidized bed is broken, making the gas-solid mixing more uniform, strengthening the mass transfer, heat transfer and gasification reaction between the gas and the solid, and improving the carbon conversion rate of the gasification device.

[0039] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination schemes. Other features and advantages of the present invention will be described in the subsequent specification, and some advantages can be made obvious from the specification, or understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained from the content specifically pointed out in the specification and the drawings. Brief Description of the Drawings

[0040] The accompanying drawings are only for the purpose of showing specific embodiments, and are not considered to be a limitation of the present invention. Throughout the drawings, the same reference signs denote the same components.

[0041] Figure 1 It is a schematic structural diagram of a multi-stage bed gasification device in the specific embodiment;

[0042] Figure 2 It is a schematic structural diagram of a connector in the specific embodiment;

[0043] Figure 3 It is a schematic diagram of the tangential circle distribution of the air inlet pipe on the transport section in the specific embodiment;

[0044] Figure 4 It is another schematic structural diagram of a multi-stage bed gasification device in the specific embodiment;

[0045] Figure 5 It is another schematic structural diagram of a connector in the specific embodiment;

[0046] Figure 6 It is still another schematic structural diagram of a multi-stage bed gasification device in the specific embodiment.

[0047] Reference signs in the drawings:

[0048] 1 - Gasifier; 101 - Feed inlet; 102 - First air inlet; 103 - Slag discharge port; 104 - Return port; 105 - Connection port; 11 - Turbulent section; 111 - Slag discharge pipe; 12 - Expansion section; 121 - Return pipe; 13 - Buffer section; 131 - Feed pipe; 2 - Connector; 201 - Second air inlet; 202 - Discharge port; 21 - Connection section; 22 - Transport section; 221 - Narrow part; 222 - Extension part; 223 - Wide part; 224 - Air inlet pipe; 3 - Gas-solid separator; 301 - Material inlet; 303 - First outlet; 303 - Second outlet; 4 - Return feeder. Specific embodiments

[0049] The following will specifically describe the preferred embodiments of the present invention in conjunction with the accompanying drawings. Among them, the accompanying drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principles of the present invention, and are not used to limit the scope of the present invention.

[0050] In the description of the embodiments of the present invention, it should be noted that unless otherwise clearly specified and limited, the term "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in the present invention can be understood according to specific circumstances.

[0051] The terms "top", "bottom", "above", "below", and "on" used throughout the description are relative positions with respect to the components of the device, such as the relative positions of the top and bottom substrates inside the device. It is understood that the devices are multifunctional and independent of their orientation in space.

[0052] The normal working surface of the present invention can be a flat surface or a curved surface, can be inclined, or can be horizontal. For the convenience of description, the embodiments of the present invention are placed on a horizontal plane and used on the horizontal plane, and "higher and lower" and "upper and lower" are defined accordingly.

[0053] Embodiment 1

[0054] This embodiment discloses a multi-stage bed gasification device, as Figures 1 to 6 shown, including:

[0055] A gasifier 1, including a turbulence section 11, an expansion section 12, and a buffer section 13 connected in sequence from bottom to top. The diameter of the expansion section 12 is not less than the diameter of the turbulence section 11, and a feed port 101 is provided at the top of the buffer section 13;

[0056] A connector 2, including a connected connection section 21 and a transport section 22, where the connection section 21 communicates with the buffer section 13;

[0057] A gas-solid separator 3, which communicates with the transport section 22;

[0058] A return feeder 4, which communicates with the gas-solid separator 3 and the expansion section 12 to return the solid material separated by the gas-solid separator 3 to the expansion section 12.

[0059] The diameter of the expansion section 12 not being less than the diameter of the turbulence section 11 means that the diameter at any point in the cavity of the expansion section 12 is not less than the diameter at any point in the cavity of the turbulence section 11.

[0060] The function of the connector is to export the gas from the buffer section 13 and at the same time entrain part of the solid material into the transport section, playing a role in connecting the gas and solid flows between the buffer section and the transport section.

[0061] The multi-stage bed gasification device of the present invention (hereinafter referred to as the gasification device) breaks the traditional annular core structure in the dilute phase region of the fluidized bed by multi-stage dividing the furnace chamber of the gasifier and connecting the gas-solid separator 3 through the connector 2, making the gas-solid mixing more uniform, strengthening the mass transfer, heat transfer and gasification reaction between the gas and the solid, and improving the carbon conversion rate of the gasification device. In addition, the feed inlet 101 is arranged at the top of the buffer section 13, and a fluidized bed gasification reaction area with sufficient fluidization and strong internal circulation is constructed at the bottom of the furnace chamber by the turbulent section 11, the expansion section 12 and the buffer section 13. The hydrocarbon fuel with high viscosity, easy to coke when heated and easy to adhere to the wall can quickly disperse and react when entering the fluidized bed gasification reaction area at the bottom of the furnace chamber, and is also prevented from being entrained by the raw gas into the connection section, thus avoiding the problem of wall adhesion.

[0062] It should be noted that the gasifier 1 is provided with a cavity (i.e., the furnace chamber) for the reaction of materials. The cavity is further divided into a turbulent section 11, an expansion section 12 and a buffer section 13. Hereinafter, the diameters of the three refer to the diameters of the corresponding cavities, and the shapes of the three also refer to the shapes of the corresponding cavities.

[0063] The centerlines of the turbulent section 11, the expansion section 12 and the buffer section 13 coincide approximately (including completely coincide) with the centerline A-A of the gasifier 1.

[0064] The turbulent section 11 is provided with a first air inlet 102 and a slag discharge port 103. Specifically, the first air inlet 102 is located at the bottom end face of the turbulent section 11, and the primary air g1 enters the gasifier 1 from the first air inlet 102, that is, the primary air g1 enters the turbulent section 11 from the first air inlet 102. The slag discharge port 103 is located at the bottom of the side wall of the turbulent section 11.

[0065] An inclined downward extending slag discharge pipe 111 is provided at the slag discharge port 103 to quickly discharge the bottom slag h generated at the bottom of the turbulent section 11. The included angle between the slag discharge pipe 111 and the centerline A-A is α, 15° ≤ α ≤ 60°, preferably, α = 30°.

[0066] Preferably, the shape of the turbulent section 11 is cylindrical, and the length of the turbulent section 11 is greater than its diameter.

[0067] The extension section 12 is a connecting section between the dense phase zone and the transition zone of the gasifier 1, and a return material port 104 is provided on the side wall of the extension section 12. The main reaction zones of the gasifier are the turbulent section and the extension section. The arrangement of the return material port on the side wall of the extension section ensures that the solid materials returned by the return feeder can smoothly enter the turbulent section; and the relatively intense turbulence in the turbulent section can be used to fully mix the returned solid materials with the high-temperature materials in the furnace and quickly heat them, enabling them to quickly participate in the reaction, thereby increasing the carbon conversion rate. The return material port 104 is communicated with the return feeder 4 to receive the solid materials transported from the return feeder 4. An upwardly inclined return pipe 121 is provided at the return material port 104, so that the solid materials separated by the gas-solid separator 3 can be quickly introduced into the extension section 12 through the return feeder 4 and the return pipe 121. The angle between the return pipe 121 and the center line A-A is β, where 15° ≤ β ≤ 60°, and preferably, β = 45°.

[0068] Preferably, the shape of the extension section 12 is an inverted truncated cone, that is, the diameter of the extension section 12 gradually increases from bottom to top, and the bottom diameter of the extension section 12 is equal to the diameter of the turbulent section 11.

[0069] The buffer section 13 is in the dilute phase zone of the furnace or between the dilute phase zone and the transition zone. A feed port 101 is provided at the top of the buffer section 13, and materials (such as hydrocarbon fuels) C enter the gasifier 1 from the top of the buffer section 13. Preferably, the feed port 101 is located at the central position of the top end face of the buffer section 13 to ensure that the materials do not contact the inner wall of the gasifier as much as possible.

[0070] For convenient feeding, a feed pipe 131 is provided at the feed port 101, and the feed pipe 131 extends vertically upward from the feed port.

[0071] A connection port 105 is provided on the side wall of the buffer section 13. The connection port 105 is connected to the connection section 21, and the materials in the buffer section 13 enter the connection section 21 through the connection port 105. The position of the connection port 105 on the buffer section 13 is lower than the feed port 101.

[0072] Preferably, a second feed port is provided on the side wall of the buffer section 13 to feed hydrocarbon fuels with low viscosity, low slagging tendency, and low wall sticking tendency into the gasifier 1. And the position of the second feed port on the side wall is higher than the connection port 105.

[0073] The included angle between the projection of the connection port 105 and the return material port 104 in the horizontal plane is 60° to 120°, preferably 90°. This angle is beneficial for structural arrangement, and the materials returned by the return material port have a longer residence time in the gasifier, which is beneficial for the reaction of fine materials.

[0074] The shape of the side wall of the buffer section 13 is cylindrical, and its top wall is arched. The diameter of the buffer section 13 is equal to the top diameter of the extension section 12.

[0075] The gasification reaction zone of the furnace of the gasifier 1 is composed of a turbulent section 11, an expansion section 12 and a buffer section 13. The particle concentration in this area is relatively high, the turbulent fluidization is intense, and the internal circulation volume is large. The hydrocarbon fuel fed from the feed port 101 falls onto the turbulent solid material layer under the action of gravity and inertia, and undergoes rapid heat transfer, dispersion and reaction under the intense turbulent fluidization, avoiding the problems of coking or slagging when the hydrocarbon fuel with high viscosity, easy to coke when heated and easy to adhere to the wall enters the furnace.

[0076] The raw coal gas and the entrained hydrocarbon solid fuel generated in the gasification reaction zone of the gasifier furnace enter the bottom of the transport section 22 from the side wall of the buffer section 13 through the connecting section 21.

[0077] According to an embodiment of the present invention, as Figure 2 and Figure 3 shown, the connecting section 21 is a straight pipe extending obliquely upward from the connecting port 105, that is, one end of the connecting section 21 is connected to the buffer section 13 (i.e., the connecting port 105), and the other end is connected to the transport section 22. The shape of the connecting section 21 is cylindrical, and the shapes of both ends are matched with the side wall of the buffer section 13 and the bottom end shape of the transport section 22 so as to be connected to the side wall of the buffer section 13 and the bottom end of the transport section 22. Specifically, the included angle between the center line of the connecting section 21 and the center line A-A of the gasifier is γ, 30° ≤ γ ≤ 60°, and preferably, γ = 45°.

[0078] The center line of the transport section 22 is parallel to the center line A-A of the gasifier. The transport section 22 expands along the gas flow direction. Specifically, the transport section 22 includes a narrow part 221, an extended part 222 and a wide part 223 connected in sequence. The diameter of the narrow part 221 is smaller than the diameter of the wide part 223. The diameter of the extended part 222 increases along the gas flow direction. The diameter of the connection end of the extended part 222 and the narrow part 221 is equal to the diameter of the narrow part 221, and the diameter of the connection end of the extended part 222 and the wide part 223 is equal to the diameter of the wide part 223.

[0079] The transport section 22 is provided with a second air inlet 201. The secondary air g2 enters the transport section 22 through the second air inlet 201, and performs gasification and combustion reactions on the solid materials and raw coal gas entering the transport section, promotes the gasification reaction in the dilute phase zone, and reduces the carbon content of the solid materials leaving the gasifier. Specifically, in order to promote the reaction between the secondary air and the solid materials and at the same time avoid excessive reaction between the secondary air and the raw coal gas, according to the concentration distribution and flow field distribution of the solid materials in the narrow part 221, the extended part 222 and the wide part 223 of the transport section, the second air inlet 201 is arranged at the lower end of the side wall of the extended part 222, and the secondary air is introduced at the position where the solid material concentration in the transport section is relatively high, which is beneficial to the reaction between the gasifying agent and the solid materials, thereby improving the carbon conversion rate.

[0080] To facilitate the control of the air intake at the second air intake port 201, an air inlet pipe 224 is provided at the second air intake port 201. Preferably, the air inlet pipe 224 at the second air intake port 201 is inclined downward or upward, so that the secondary air g2 entering from the air inlet pipe 224 enters the lower part of the transport section 22 in an inclined upward or inclined downward manner.

[0081] The included angle δ between the opening direction of the second air intake port 201 (i.e., the air intake direction of the air inlet pipe 224) and the horizontal plane (a plane perpendicular to the center line of the transport section 22) is -60° ≤ δ ≤ 60°, preferably, -30° ≤ δ ≤ 30°. The secondary air promotes the diffusion of the wall-attached and recirculated solid materials towards the center and mixes with the secondary air to form a stable solid material flow field with an upward center and a wall-side recirculation. It should be noted that when δ is a positive number, the air inlet pipe 224 extends obliquely upward from the second air intake port 201, that is, the air intake direction of the air inlet pipe 224 enters the transport section in an inclined downward manner; when δ is a negative number, the air inlet pipe 224 extends obliquely downward from the second air intake port 201, that is, the air intake direction of the air inlet pipe 224 enters the transport section in an inclined upward manner; when δ is zero, the air inlet pipe 224 is horizontally arranged, that is, the air intake direction of the air inlet pipe 224 is perpendicular to the center line of the transport section 22. In this embodiment, γ = 25°.

[0082] Preferably, a plurality of second air intake ports 201 are provided at the lower part of the extension part, and correspondingly, an equal number of air inlet pipes 224 are provided, that is, the air inlet pipes 224 and the second air intake ports 201 are arranged in a one-to-one correspondence. The plurality of second air intake ports 201 are located on the same horizontal plane, that is, the plurality of second air intake ports 201 are set at the same height on the transport section 22. The included angles of the plurality of air inlet pipes 221 with the horizontal plane are the same.

[0083] Furthermore, the plurality of air inlet pipes 221 introduce the secondary air g2 in a tangential circle form, that is, the air intake directions of the plurality of air inlet pipes 221 are tangent to the same circle O (circle O is also called the tangential circle), as Figure 3 shown, the center line of the transport section 22 passes through the center of the circle O, and the diameter D of the circle O is smaller than the diameter of the second air intake port opening of the extension part 222. Preferably, the diameter D of the circle O is greater than or equal to the diameter of the connection section 21 and less than or equal to 0.85 times the diameter of the second air intake port opening of the extension part 222. In the lower part of the transport section, a flow field is formed in which the solid materials form a central jet flowing upward and a wall-side downward recirculation; the concentration of the solid material particles is the highest within the range of 0.85 times the cross-sectional diameter and the diameter of the connection section. Therefore, taking this range of diameters as the tangential circle diameter range will effectively promote the mixing, mass transfer, heat transfer, and reaction between the secondary air and the solid materials, thus strengthening the gasification reaction. At the same time, introducing the secondary air in a tangential circle form promotes the mixing of the solid materials flowing downward along the wall and the diffusion towards the center, avoiding the problems of wall surface overheating and slagging caused by tangentially introducing the secondary air.

[0084] The number of the intake pipes 224 is not less than three. In this embodiment, the number of the intake pipes 224 is four, and they are evenly distributed on the lower side wall of the extension part 222.

[0085] The shape of the narrow part 221 is cylindrical. One end of the narrow part 221 is connected to the connection section 21, and the other end is connected to the extension part 222. The diameter of the narrow part 221 is equal to that of the connection section. The shape of the extension part 222 is an inverted frustum of a cone or a horn shape. The diameter of the extension part 222 gradually increases along the gas flow direction (from bottom to top). The bottom diameter of the extension part 222 is equal to the diameter of the narrow part 221. The shape of the wide part 223 is cylindrical, and the diameter of the wide part 223 is equal to the diameter of the top end of the extension part 222. That is, the bottom end of the extension part 222 extends vertically downward to form the narrow part 221, and the top end of the extension part 222 extends vertically upward to form the wide part 223.

[0086] The raw coal gas entraining hydrocarbon solid fuel enters the transport section 22 through the connection section 21. As the diameter increases, the gas flow rate decreases, and the hydrocarbon solid fuel has a reflux and backmixing at the connection between the connection section 21 and the transport section 22, showing an increase in particle concentration. In this area, secondary air is introduced in a tangential circle form to strengthen the mixing and reaction of the secondary air with the hydrocarbon solid fuel. At the same time, the secondary air introduced in a tangential circle form will change the gas-solid annular core structure in the transport section, making the gas-solid present a swirling upward flow, and strengthening the mass transfer, heat transfer and gasification reaction between the gas and the solid.

[0087] According to another embodiment of the present invention, as Figures 4 to 5 shown, the connector 2 includes two connection sections 21. Correspondingly, two connection ports 105 are oppositely opened on the side wall of the buffer section 13. One end of each of the two connection sections 21 is connected to a connection port 105, and the other ends of the two connection sections 21 are connected to the bottom of the transport section 22, that is, the other ends of the two connection sections converge at the bottom of the transport section 22. Specifically, the transport section 22 is located above the gasifier 1, and the center line of the transport section 22 coincides with the center line A-A of the gasifier. The two connection ports 105 are symmetrically arranged on both sides of the center line A-A, and the two connection sections 21 are symmetrically arranged on both sides of the center line A-A. The center line A-A passes through the connection (also called the convergence point) between the two connection sections 21 and the transport section 22.

[0088] The connection section 21 extends upward from the connection port 105 of the buffer section 13 to the bottom of the transport section 22. In this embodiment, the shape of the connection end 21 is a pipe similar to a "C" shape.

[0089] At this time, the second air inlet 201 is opened at the converging place, and the secondary air g2 is injected into the transport section 22 in a central jet mode, and the apparent wind speed of the secondary air is 30-60 m / s. Specifically, the air inlet direction of the second air inlet 201 is vertically upward, and the center line A-A passes through the second air inlet 201, that is, the second air inlet is located between the two connecting ends 21. The second air inlet 201 extends vertically downward to form an air inlet pipe 224. With such a setting, the two connecting sections 21 converge with the transport section 22 in an upward-inclined form. In the converging area (i.e., the converging place), the solid material converges to the center of the converging place under the entrainment of the raw gas and fully contacts and reacts with the secondary air flowing in through the central jet, which is beneficial to strengthening the gas-solid reaction and improving the carbon conversion rate.

[0090] According to another embodiment of the present invention, as Figure 6 shown, the connection port 105 is opened at the center of the top of the buffer section 13, the connecting section 21 is located directly above the buffer section 13, and the transport section 22 is located directly above the connecting end 21. That is, the center line A-A passes through the connection port 105, and the center lines of the connecting section 21 and the transport section 22 coincide with the center line A-A.

[0091] Specifically, the shape of the connecting section 21 is cylindrical, and the diameter of the connecting section 21 is not greater than the diameter of any part of the buffer section 13. The bottom end of the connecting section 21 is connected to the buffer section 13 (i.e., the connection port 105), and the top end of the connecting section 21 is connected to the transport section 22.

[0092] The lower part of the transport section 22 is in the shape of an inverted truncated cone, that is, the diameter of the lower part of the transport section 22 gradually increases from bottom to top, and the diameter of the bottom end of the lower part of the transport section 22 is equal to the diameter of the connecting end 21. The upper part of the transport section 22 is in the shape of a cylinder, and the diameter of the upper part of the transport section is equal to the diameter of the top end of the lower part of the transport section 22, that is, the top end of the lower part of the transport section 22 extends vertically upward to form the upper part of the transport section 22.

[0093] The lower structure of the transport section 22 is the same as that of the aforementioned extension part 222, that is, it is provided with a second air inlet and an air inlet pipe with the same structure ( Figure 6 not shown), which will not be elaborated here.

[0094] Preferably, at this time, the top shape of the buffer section 13 is a frustum of a cone, that is, the top diameter of the buffer section 13 gradually decreases from bottom to top, and the diameter of the top end of the buffer section 13 is the same as the diameter of the connecting section 21, that is, the connecting port 105 is a round hole, and the aperture of the connecting port 105 is the diameter of the connecting section 21. An inlet port 101 is provided on the inclined side wall of the top of the buffer section 13, and a feed pipe 131 is provided at the inlet port 101. The feed pipe 131 extends obliquely upward from the inlet port, and the included angle between the feed pipe 131 and the horizontal plane is ζ, 60° ≤ ζ ≤ 85°, so as to ensure that the materials from the inlet port 101 can be quickly dispersed and reacted without wall sticking.

[0095] An outlet port 202 is provided on the upper part of the side wall of the transport section 22, and the outlet port 202 is communicated with the gas-solid separator 3.

[0096] The gas-solid separator 3 is provided with a material inlet 301, a first outlet 303 and a second outlet 303. The material inlet 301 is communicated with the outlet port 202, so that the materials discharged from the outlet port 202 can enter the gas-solid separator 3 through the material inlet 301 for gas-solid separation. The gas separated by the gas-solid separator 3 is guided to the downstream device for treatment through the first outlet 303, and the separated solid is exported through the second outlet 303 and returned to the expansion section 12 of the gasifier through the return feeder 3 for reprocessing.

[0097] The material inlet 301 is located at the upper end of the side wall of the gas-solid separator, the first outlet 302 is located at the top of the gas-solid separator, and the second outlet 303 is located at the bottom of the gas-solid separator.

[0098] Preferably, the gas-solid separator 3 is a high-efficiency cyclone separator or other high-efficiency gas-solid separators.

[0099] The return feeder 4 is respectively communicated with the second outlet 303 and the return port 104, so as to transport the solid materials separated by the gas-solid separator 3 back to the gasifier 1 for reprocessing.

[0100] The return feeder 4 is a non-mechanical return device, which can be a U-valve, a J-valve, an N-valve, an L-valve, or a jet conveyor. The return feeder 4 can automatically adjust the riser inventory height according to the pressure change in the gasifier cavity.

[0101] In the gasification device of the present invention, the gasifier constitutes a fluidized bed gasification reaction zone, and the connector constitutes a swirling transport bed gasification zone. The upward fluidization velocity in the fluidized bed gasification reaction zone decreases along the axis. Specifically, the superficial fluidization velocity in the turbulent section 11 is 2.5 m / s to 6 m / s, the superficial fluidization velocity in the expansion section 12 is 1.5 m / s to 3 m / s, and the superficial fluidization velocity in the buffer section 13 is 0.8 m / s to 2 m / s.

[0102] In the fluidized bed gasification reaction zone, the upward fluidization velocity decreases along the axial direction, which not only ensures sufficient fluidization of the solid materials in the turbulent section 11 and the expansion section 12 at the bottom of the furnace, bringing a strong material diffusion ability and heat and mass transfer rates, but also ensures a large amount of internal circulation and the weak gas entrainment ability of the buffer section 13. The gas-solid flow field constructed in the fluidized bed gasification reaction zone enables the high-viscosity, heat-sensitive, coking-prone, and wall-hanging hydrocarbon fuel fed from the top to be quickly dispersed, heated, and reacted under the action of the solid materials with sufficient fluidization and strong internal circulation, avoiding coking and wall-hanging. At the same time, the lower gas velocity in the buffer section 13 prevents this type of hydrocarbon fuel from being entrained by the raw gas into the connection section 21, avoiding coking and wall-hanging phenomena in the connection section 21.

[0103] The connection section 21 and the transport section 22 form a cyclone transport bed gasification zone. The superficial fluidization velocity of the connection section 21 is 8 m / s to 15 m / s; the superficial fluidization velocity of the transport section 22 is 5 m / s to 10 m / s.

[0104] The multi-stage bed gasification device of the present invention uses a staged air distribution method to achieve staged gasification of hydrocarbon fuels, thereby improving the carbon conversion rate. Among them, the primary air g1 is introduced from the bottom of the furnace. This area is the dense phase zone of the furnace with a relatively high particle concentration and temperature. To avoid slagging, the oxygen concentration of the primary air g1 is set to 15% to 45%, and the oxygen concentration of the secondary air g2 is 21% to 60%; the proportion of the primary air in the total amount of gasification agent is 65% to 90%. The secondary air g2 is preferably introduced in a uniformly distributed tangential circle manner, and the flow velocity of the secondary air nozzle is 45 m / s to 100 m / s. Through the tangential injection method, the downward solid materials on the sidewall are swirled and fluidized towards the center, and the gasification agent is sprayed into the fluidized gasification zone at a high speed to strengthen the diffusion of the gasification agent and temperature and the gasification reaction, avoiding slagging.

[0105] The technical problems to be solved by the gasification device of the present invention include: in the existing fluidized bed gasification technology, in the upper dilute phase zone of the furnace, the particle concentration is low and unevenly distributed, with a significant core-annulus structure, the gas phase is in the center, and the particles are close to the wall, which is not conducive to material dispersion and gas-solid reaction, resulting in low reaction space utilization rate in the dilute phase zone and high carbon content in fly ash; for hydrocarbon fuels with high viscosity, heat-sensitive, coking-prone, and wall-hanging characteristics, conventional furnace structures and feeding positions have problems such as coking and wall-hanging near the feeding port, bringing risks of stopping the furnace caused by damage to the air distribution device and slagging in the furnace.

[0106] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0107] (1) The present invention realizes staged gasification reactions through staged gasification agents, breaks the core-annulus structure in the dilute phase zone of the traditional fluidized bed, makes the mixing between gas and solid more uniform, strengthens the mass transfer, heat transfer, and gasification reactions between gas and solid, thereby improving the carbon conversion rate;

[0108] (2) For hydrocarbon fuels with high viscosity, prone to coking when heated, and prone to wall sticking, the present invention sets the feed inlet at the top of the buffer section 13. The furnace fluidized bed gasification reaction area with sufficient fluidization and strong internal circulation is constructed by the turbulent section 11, the expansion section 12, and the buffer section 13. The hydrocarbon fuels with high viscosity, prone to coking when heated, and prone to wall sticking can quickly disperse and react when entering the fluidized bed gasification reaction area at the bottom of the furnace, and at the same time, it can avoid the wall sticking problem caused by being entrained by the raw gas into the connection section. The present invention well solves the problems of stable feeding and gasification of hydrocarbon fuels with high viscosity, prone to coking when heated, and prone to wall sticking.

[0109] Example Two

[0110] This example discloses a gasification method of a multi-stage bed gasification device, which is realized by the multi-stage bed gasification device provided in Example One. The gasification method includes:

[0111] Import solid fuel into the gasification furnace 1 through the feed inlet 101;

[0112] Import the gasifying agent from the first air inlet 102 and the second air inlet 201;

[0113] Among them, the superficial fluidization velocity of the turbulent section 11 is 2.5 m / s to 6 m / s, the superficial fluidization velocity of the expansion section 12 is 1.5 m / s to 3 m / s, and the superficial fluidization velocity of the buffer section 13 is 0.8 m / s to 2 m / s;

[0114] The superficial fluidization velocity of the connection section 21 is 8 m / s to 15 m / s; the superficial fluidization velocity of the transport section 22 is 5 m / s to 10 m / s;

[0115] The primary air is imported into the gasification furnace from the first air inlet 102, and the oxygen concentration of the primary air g1 is set to 15% to 45%; the proportion of the primary air in the total amount of the gasifying agent is 65% to 90%;

[0116] The secondary air is imported into the connector from the second air inlet 201, and the oxygen concentration of the secondary air g2 is 21% to 60%; the secondary air g2 is introduced in a uniformly distributed tangential circle manner, and the nozzle flow velocity of the secondary air g2 is 45 m / s to 100 m / s.

[0117] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A multi-stage bed gasification device, characterized in that, Comprising: A gasifier including a turbulent section, an expansion section, and a buffer section connected in sequence from bottom to top. The diameter of the expansion section is not less than that of the turbulent section, and a feed inlet is provided at the top of the buffer section; A connector including a connecting section and a transport section connected. The connecting section communicates with the buffer section; A gas-solid separator communicating with the transport section; A recycle feeder communicating with the gas-solid separator and the expansion section for returning the solid material separated by the gas-solid separator to the expansion section.

2. The multi-stage bed gasification device according to claim 1, wherein The turbulent section is provided with a first air inlet and a slag discharge port; The first air inlet is located at the bottom end face of the turbulent section; The slag discharge port is located at the bottom of the side wall of the turbulent section.

3. The multi-stage bed gasification device according to claim 1, characterized in that, The expansion section is a connecting section between the dense phase zone and the transition zone of the gasifier. A recycle port is provided on the side wall of the expansion section, and the recycle port communicates with the recycle feeder.

4. The multi-stage bed gasification device according to claim 1, characterized in that, The buffer section is the dilute phase zone of the furnace or between the dilute phase zone and the transition zone; A connection port is provided on the side wall of the buffer section, and the connection port is connected to the connecting section.

5. The multi-stage bed gasification device according to any one of claims 1 to 4, characterized in that, The connecting section is a straight pipe extending obliquely upward from the connection port of the buffer section; The center line of the transport section is parallel to the center line of the gasifier, and the transport section expands along the gas flow direction; The transport section is provided with a second air inlet, and secondary air enters the transport section through the second air inlet.

6. The multi-stage bed gasification device according to claim 5, characterized in that, The transport section is provided with a plurality of second air inlets, and an air inlet pipe is provided at each second air inlet; A plurality of air inlet pipes introduce secondary air in a tangential circle form.

7. The multi-stage bed gasification device according to any one of claims 1 to 4, characterized in that, The connector includes two connecting sections. One ends of the two connecting sections are respectively connected to the buffer section, and the other ends of the two connecting sections are connected to the bottom of the transport section; The transport section is located above the gasifier, and the center line of the transport section coincides with the center line of the gasifier; A second air inlet is provided at the connection of the two connecting sections and the transport section, and secondary air is sprayed into the transport section by a central jet through the second air inlet.

8. The multi-stage bed gasification device according to any one of claims 1 to 4, characterized in that, The connecting section is connected to the top of the buffer section; The connecting section is located above the buffer section, and the transport section is located above the connection end; The top shape of the buffer section is a frustum of a cone, and the feed inlet is provided on the inclined side wall at the top of the buffer section.

9. The multi-stage bed gasification device according to claim 8, wherein, The lower part of the transport section is in the shape of an inverted frustum of a cone; The lower part of the transport section is provided with a plurality of second air inlets, and an air inlet pipe is provided at each second air inlet; A plurality of air inlet pipes introduce secondary air in a tangential circle form.

10. A gasification method of a multi-stage bed gasification device, implemented by the multi-stage bed gasification device according to any one of claims 1 to 9. The gasification method includes: Introducing solid fuel into the gasifier through the feed inlet; Introducing gasifying agent through the first air inlet and the second air inlet; Wherein, the superficial fluidization velocity of the turbulent section is 2.5 m / s to 6 m / s, the superficial fluidization velocity of the expansion section is 1.5 m / s to 3 m / s, and the superficial fluidization velocity of the buffer section is 0.8 m / s to 2 m / s; The superficial fluidization velocity of the connecting section is 8 m / s to 15 m / s; the superficial fluidization velocity of the transport section is 5 m / s to 10 m / s; The primary air is introduced into the gasifier through the first air inlet, the oxygen concentration of the primary air is set to 15% - 45%, and the proportion of the primary air in the total amount of gasifying agent is 65% - 90%; The secondary air is introduced into the connector through the second air inlet, and the oxygen concentration of the secondary air is 21% - 60%; the secondary air is introduced in a uniformly distributed tangential circle mode, and the flow velocity of the secondary air nozzle is 45m / s - 100m / s.

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