Plasma gun assisted biomass and / or coal gasification device and method

Abstract

The invention discloses a plasma gun assisted biomass and / or coal gasification device and method, belongs to the technical field of biomass and / or coal gasification, and solves the problems of local overheating and non-uniform temperature distribution in the prior art. The biomass and / or coal gasification device assisted by the plasma gun comprises a gasification furnace, wherein the plasma gun is arranged on the side surface of the gasification furnace. The plasma guns are arranged on the side face of the gasification furnace in a grading mode, and tar can be decomposed more thoroughly.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass and / or coal gasification, and in particular relates to a plasma gun assisted biomass and / or coal gasification device and method. Background Art

[0002] Coal is one of the world's most important fossil energy sources, but its use produces a large amount of carbon dioxide and other pollutants, causing serious environmental problems.

[0003] There are many types of biomass, including agricultural and forestry waste, organic waste, etc. As a renewable resource, biomass has the characteristics of carbon neutrality, that is, the carbon dioxide emitted by its combustion can be absorbed during the growth process, thus reducing the net emission of greenhouse gases.

[0004] Co-gasification of biomass and coal can reduce coal consumption and increase the proportion of renewable energy in the energy structure, which is conducive to the adjustment of energy structure; co-gasification of biomass and coal can also effectively treat waste, reduce environmental pollution, convert waste into useful gas fuels or chemicals, and realize the comprehensive utilization of resources. Compared with gasifying biomass or coal alone, co-gasification of biomass and coal can make full use of the advantages of both raw materials and reduce energy consumption and costs in the gasification process. For example, biomass has a lower melting point, which may lead to slagging problems in the gasification process, while coal has a higher melting point, which can alleviate this problem.

[0005] Conventional gasifiers usually place plasma guns at the bottom of the gasifier, and use bottom heating to provide a high-temperature heat source for the gasification process. However, this arrangement has problems such as local overheating and uneven temperature distribution, which can easily lead to insufficient reaction of materials in the furnace or slagging, reducing gasification efficiency and gas production quality. Summary of the invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the problems of local overheating and uneven temperature distribution in the prior art, thereby providing a plasma gun assisted biomass and / or coal gasification device and method.

[0007] To this end, the present invention provides the following technical solutions:

[0008] In a first aspect, the present invention provides a plasma gun assisted biomass and / or coal gasification device, comprising a gasifier, wherein a plasma gun is disposed on a side of the gasifier.

[0009] Coal and biomass may enter the gasifier through the same or different inlets.

[0010] In a possible implementation, the plasma guns are arranged in multiple stages; the multiple stages refer to the plasma guns being arranged at different positions in the height direction of the gasifier. Multiple stages refer to two stages or more.

[0011] Optionally, the plasma gun includes a primary plasma gun and a secondary plasma gun;

[0012] Optionally, the height h1 of the primary plasma gun is greater than the height h2 of the secondary plasma gun.

[0013] Optionally, a plurality of first-stage plasma guns are provided and evenly distributed around the circumference of the gasifier.

[0014] Optionally, a plurality of secondary plasma guns are provided and evenly distributed around the circumference of the gasifier.

[0015] Several refers to 1 or 2 or more.

[0016] In a possible implementation, the height h1 of the primary plasma gun is 0.06h to 0.35h, where h is the height of the gasifier;

[0017] and / or

[0018] The height h2 of the secondary plasma gun is 0.03h-0.25h.

[0019] In a possible implementation, the gasification device further includes a biomass feeding device and a coal powder feeding device;

[0020] A pulverized coal inlet and a biomass inlet are arranged opposite to each other on the side of the gasifier, a pulverized coal feeding device is connected to the pulverized coal inlet, and a biomass feeding device is connected to the biomass inlet.

[0021] The pulverized coal inlet and the biomass inlet arranged opposite to each other may be arranged completely symmetrically on the gasifier, or may be arranged in an incompletely symmetrical manner;

[0022] Specifically, the height difference between the relatively arranged pulverized coal inlet and the biomass inlet in the vertical direction is h3-h4; the pulverized coal inlet and the biomass inlet form an angle of 160° to 200° with the center of the gasifier in the horizontal direction.

[0023] When h3-h4=0, the pulverized coal inlet and the biomass inlet form an angle of 180° with the center of the gasifier in the horizontal direction, the pulverized coal inlet and the biomass inlet are completely symmetrically arranged.

[0024] When h3-h4≠0 and / or the included angle≠180°, the pulverized coal inlet and the biomass inlet are not completely symmetrically arranged.

[0025] Preferably, the height of the coal powder inlet is h3, the height of the biomass inlet is h4, h is the height of the gasifier, and h3-h4=0-0.2h;

[0026] More preferably, h3-h4=0~0.05h.

[0027] In one possible implementation, h3 is 0.1h to 0.6h, preferably 0.3h to 0.6h;

[0028] In a possible implementation manner, h4 is 0.1h to 0.5h, preferably 0.3h to 0.5h.

[0029] In a possible implementation, the biomass feeding device includes a biomass hopper, a screw feeder, a tubular heater and a biomass conveying pipeline connected in sequence;

[0030] In a possible implementation, the tubular heater includes a first heating section and a second heating section; the first heating section is a steam or gas heating section, and the second heating section is a plasma heating section.

[0031] In a possible implementation, the biomass conveying pipeline is inclined downward;

[0032] Preferably, the biomass conveying pipeline is at an angle of 10° to 80° with the horizontal plane. The biomass conveying pipeline is tilted downward, which can give the biomass a natural downward force and prevent blockage to a certain extent.

[0033] The working fluid of the plasma gun of the plasma heating section and the plasma gun arranged on the side of the gasifier can be independently selected from gases such as air, oxygen, nitrogen, argon, water vapor, etc., preferably water vapor. When the working fluid of the plasma gun of the plasma heating section is water vapor and the first heating section is heated by water vapor, the first heating section and the second heating section can share a water vapor pipeline to save materials. When the plasma gun arranged on the side of the gasifier uses water vapor as the working fluid, it can increase the concentration and temperature of hydrogen and oxygen ions in the reactor (the temperature of the plasma gun can reach 1500°C) and promote the reaction, and water vapor is cheaper and easier to obtain as a working fluid.

[0034] In a second aspect, the present invention provides a method for gasifying biomass and / or coal, using the above-mentioned plasma gun-assisted biomass and / or coal gasification device.

[0035] In a possible implementation, the gasification method comprises the following steps:

[0036] Biomass and / or pulverized coal are added to the gasifier, and a gasifying agent is introduced; the temperature in the gasifier is 800-1200°C, and the biomass and / or pulverized coal reacts with the gasifying agent to form raw coal gas;

[0037] Preferably, the method further comprises separating the raw coal gas into gas and solid, conveying the separated gas to a high-temperature heat exchanger to preheat the gasifying agent to be introduced into the gasifier, and conveying the separated solid back to the gasifier.

[0038] The gasifying agent exchanges heat with the raw coal gas discharged from the gasifier in the high-temperature heat exchanger, and the preheated gasifying agent is introduced into the gasifier, which can fully utilize the waste heat, increase the temperature of the gasifying agent, and improve the reaction activity.

[0039] Optionally, biomass and pulverized coal can be fed into the gasifier through a biomass feeding device and a pulverized coal feeding device, respectively. The feeding sequence is not limited to feeding biomass and pulverized coal at the same time, and different fuels can be added in stages (e.g., pulverized coal is fed first, and then biomass) to control the progress and temperature distribution of the gasification reaction.

[0040] In a possible implementation, biomass and pulverized coal may also enter the gasifier through the same feeding device.

[0041] In a possible implementation, the biomass is heated to 150-300° C. in a tubular heater and then enters the gasifier.

[0042] Heating biomass to 150-300℃ in a tubular heater can not only reorganize the biomass macromolecular structure and break the bonds, achieving the purpose of initial cracking and pressurization and heating, but also avoid the generation of tar and clogging of pipelines due to excessive temperature. It can also avoid the cost increase caused by higher requirements on pipeline materials due to excessive temperature.

[0043] In one possible implementation, biomass is co-gasified with pulverized coal, which improves the utilization rate of biomass and solves the scale problem caused by seasonal supply fluctuations in biomass gasification alone.

[0044] The present invention solves the problems of low reaction efficiency, uneven heat source supply, uneven material distribution and unreasonable temperature field distribution in the existing gasification technology through innovative technologies such as co-gasification of coal and biomass, staged heating of water vapor and plasma, symmetrical feeding to form hedging, and graded arrangement of plasma guns on the sides of the gasifier, thereby realizing an efficient, stable and clean gasification process.

[0045] The gasifying agent includes one or more of water vapor and oxygen-enriched air.

[0046] The technical solution of the present invention has the following advantages:

[0047] 1. The plasma gun assisted biomass and / or coal gasification device of the present invention comprises a gasifier, and a plasma gun is arranged on the side of the gasifier.

[0048] The present invention arranges the plasma guns in stages on the side of the gasifier, so that the high-temperature combustion zone moves upward, the tar stays in the high-temperature combustion zone for a longer time and decomposes more thoroughly, the tar cracking effect is better, the gasifier blockage caused by tar deposition is reduced, and the temperature in the gasifier can be adjusted more flexibly, so that the gasification effect is better and the gas production quality is improved.

[0049] 2. The plasma gun of the present invention is multi-staged, which can make the heat release range of the plasma gun larger and the heating effect better. It can also control the temperature distribution of different areas in the gasifier, thus improving the reaction uniformity during the gasification process.

[0050] 3. The plasma gun assisted biomass and / or coal gasification device of the present invention includes a biomass feeding device and a coal powder feeding device; a coal powder inlet and a biomass inlet are relatively arranged on the side of the gasifier, the coal powder feeding device is connected to the coal powder inlet, and the biomass feeding device is connected to the biomass inlet.

[0051] Mixed feeding of biomass and coal can easily lead to uneven distribution of materials in the gasifier, affecting the uniformity and stability of the reaction, reducing the gasification efficiency, causing fluctuations in the gas production composition, and reducing the gas production quality, making it difficult to achieve an efficient and stable co-gasification process.

[0052] The present invention feeds coal powder and biomass separately, and the conveying conditions and conveying volume ratio can be controlled by the material properties of biomass and coal powder, respectively, so that the feeding method is more flexible and resource waste is reduced. The coal powder inlet and the biomass inlet are arranged relative to each other, so that the exploded biomass and the coal powder pneumatically conveyed to the gasifier are offset, and the coal powder and biomass are mixed more evenly in the gasifier, avoiding the local overheating and cooling caused by uneven mixing, and enhancing the efficiency of combustion and gasification reactions.

[0053] 4. The height of the pulverized coal inlet is h3, and the height of the biomass inlet is h4. h is the height of the gasifier, and h3-h4=0~0.2h.

[0054] Compared with biomass, coal powder has a higher density and a heavier weight. Setting the height of the coal powder inlet slightly higher than the biomass inlet is more conducive to the mixing of biomass and coal powder.

[0055] 5. The biomass feeding device comprises a biomass hopper, a screw feeder, a tubular heater and a biomass conveying pipeline which are connected in sequence, and the biomass conveying pipeline is connected to the biomass inlet.

[0056] By pretreating the biomass in a tubular heater (i.e., primary cracking) and heating and pressurizing the biomass, the biomass can be instantly exploded when entering the gasifier, making the biomass more evenly distributed in the gasifier, greatly improving the reaction activity, and burning more completely, making it easier to mix with coal powder in the furnace, thereby improving gasification efficiency and reducing pollutant emissions.

[0057] 6. The tubular heater includes a first heating section and a second heating section; the first heating section is a steam or gas heating section, and the second heating section is a plasma heating section. Plasma heating has the advantages of concentrated heat, high temperature and no pollution. Plasma transfers heat in three ways: radiation, arc spots and thermal convection, which greatly expands the heated area and improves the heat transfer efficiency. In a single cracking, the tubular heater has a small space, and the plasma gun releases heat more concentratedly to the biomass in the tubular heater, which has a better heating effect and a better pressurization effect, so that the biomass is more evenly distributed when entering the gasifier and burns more fully. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0059] Figure 1 This is a schematic diagram of a plasma gun-assisted biomass and / or coal gasification device according to Example 1;

[0060] Figure 2 This is a schematic diagram of the biomass and coal co-gasification method in Example 2.

[0061] Reference numerals:

[0062] 1-biomass hopper, 2-screw feeder, 3-tubular heater, 301-steam heating section, 302-plasma heating section, 303-steam inlet, 304-primary cracking plasma gun, 4-coal powder storage hopper, 5-screw feeder, 6-charging port, 7-pneumatic conveying pipeline, 8-differential pressure measuring device, 9-inlet valve, 10-gasifier, 11-gasifying agent inlet, 12-first-stage plasma gun, 13-second-stage plasma gun, 14-return port, 15-slag cooler. DETAILED DESCRIPTION

[0063] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0064] If no specific experimental steps or conditions are specified in the examples, the experiments can be carried out according to the conventional experimental steps or conditions described in the literature in the art.

[0065] Example 1

[0066] A plasma gun assisted biomass and / or coal gasification device, such as Figure 1 , Figure 2 As shown, it includes a gasifier, a biomass feeding device and a coal powder feeding device; the coal powder inlet and the biomass inlet are arranged opposite to each other on the side of the gasifier, the coal powder feeding device is connected to the coal powder inlet, and the biomass feeding device is connected to the biomass inlet. The gasifier is a fluidized bed gasifier.

[0067] The height of the gasifier is h, the height h4 of the biomass inlet from the bottom of the gasifier is 0.4h, and the height h3 of the pulverized coal inlet from the bottom of the gasifier is 0.45h.

[0068] The biomass feeding device comprises a biomass hopper 1, a screw feeder 2, a tubular heater 3 and a biomass conveying pipeline which are connected in sequence, and the biomass conveying pipeline is connected to the biomass inlet; the tubular heater 3 comprises a water vapor heating section 301 and a plasma heating section 302. The water vapor heating section 301 is provided with a water vapor inlet 303, and the plasma heating section 302 is provided with a primary cracking plasma gun 304.

[0069] The biomass hopper 1 is used to store the biomass raw materials after drying; a screw feeder 2 is fixedly installed below the biomass hopper 1 to stably transport the biomass raw materials to the gasifier; the tubular heater 3 is used to pre-treat the biomass (primary cracking), and the length of the tubular heater 3 is 6m, of which the length of the steam heating section 301 is 4m, and the length of the plasma heating section 302 is 2m.

[0070] The biomass conveying pipeline is inclined downward, and the biomass conveying pipeline forms an angle of 20° with the horizontal plane.

[0071] The pulverized coal feeding device includes a pulverized coal storage hopper 4, a screw coal feeder 5, a pressure charging port 6, a pneumatic conveying pipeline 7, a differential pressure measuring device 8, and an inlet valve 9. The pulverized coal storage hopper 4 is used to store the pulverized coal delivered from the coal mill to ensure stable pulverized coal feeding; a screw coal feeder 5 is fixedly installed under the pulverized coal storage hopper 4 to stably deliver the pulverized coal to the pneumatic conveying pipeline 7. A pressure charging port 6 is provided on the upper part of the pneumatic conveying pipeline 7. The pulverized coal is pneumatically delivered to the gasifier 10. A differential pressure measuring device 8 and an inlet valve 9 are installed on the pneumatic conveying pipeline. The differential pressure measuring device measures the pressure difference between the coal tank and the gasifier, and the opening of the inlet valve is adjusted according to the pressure difference measurement value to ensure that the pulverized coal can be stably delivered to the gasifier. The pressure difference is generally maintained at 0.001-0.8MPa.

[0072] The plasma gun assisted biomass and / or coal gasification device also includes a plasma gun arranged in two levels at different heights on the side of the gasifier, providing a high temperature environment for the gasifier so that the temperature in the furnace reaches 800-1200°C. Specifically, the plasma gun includes a primary plasma gun 12 and a secondary plasma gun 13, and both the primary plasma gun 12 and the secondary plasma gun 13 are arranged below the biomass inlet and the coal powder inlet. The primary plasma gun 12 is at a height of h1=0.3h from the bottom of the gasifier, and the secondary plasma gun 13 is at a height of h2=0.2h from the bottom of the gasifier. There are 4 primary plasma guns 12 and 4 secondary plasma guns 13, and they are evenly arranged circumferentially around the gasifier.

[0073] The gasifier further comprises a gasifying agent inlet 11 and a return material port 14 , and a slag cooler 15 is fixedly installed at the bottom of the gasifier.

[0074] The pretreated biomass explodes the moment it enters the gasifier 10, and at the same time, the symmetrically arranged coal powder feeding device enters the gasifier at a certain initial velocity after pneumatic conveying. The two are mixed in the gasifier and cracked and gasified together. The gasifier inlet 11 is used to provide the gasifier with gasifier treated by the high-temperature heat exchanger, provide heat and oxidant for the reaction in the gasifier, and promote the reaction in the furnace. The primary plasma gun 12 and the secondary plasma gun 13 are arranged at different heights on the side of the gasifier to achieve controllable heating of different areas of the gasifier, so that the high-temperature combustion zone moves upward, the concentration and temperature of hydrogen and oxygen ions in the reactor are increased, and the reaction is promoted. After the reaction is completed, the raw coal gas and part of the fly ash produced by the gasifier are sent to the gas-solid separator connected to the top of the gasifier for gas-solid separation. The gas-solid separator can be a cyclone separator. The separated gas is sent to the high-temperature heat exchanger to heat the gasifying agent to make full use of the waste heat, and the fly ash is sent back to the furnace through the return port 14 at the bottom of the gasifier for re-gasification; the ash and incompletely burned impurity particles produced after the reaction are discharged into the slag cooler 15 connected to the bottom of the gasifier to prevent the accumulation of residues and the obstruction of the gasification process.

[0075] Example 2

[0076] This embodiment provides a method for co-gasification of biomass and coal, using the device of embodiment 1, comprising:

[0077] (1) Biomass feeding: The dried biomass is transported to the biomass hopper, and the screw feeder 2 stably transports the biomass to the tubular heater 3. After the biomass undergoes primary cracking and gasification in the tubular heater 3, it enters the gasifier for secondary cracking and gasification.

[0078] The front-end heating method of the tubular heater 3 is steam heating, and the rear-end heating method is plasma gun heating with steam as the working fluid. The biomass enters the gasifier after the temperature is raised to 150-300°C in the tubular heater 3. The heated biomass expands rapidly and explodes at the moment of entering the gasifier, and is evenly scattered in the gasifier.

[0079] (2) Coal powder feeding: The coal powder in the coal powder storage hopper 4 is pneumatically conveyed into the gasifier, where it collides with the biomass that enters the gasifier through the oppositely arranged biomass inlet and is exploded, and the two are mixed.

[0080] The primary plasma gun and the secondary plasma gun provide a high temperature environment for the gasifier, making the temperature inside the furnace reach 800-1200°C. After the pulverized coal and the biomass after primary cracking enter the gasifier and mix, they are cracked and gasified under the action of the gasifying agent to form raw coal gas.

[0081] (3) Discharge of gasification products: The raw coal gas and part of the fly ash generated in the gasifier are discharged from the upper part of the gasifier and enter the gas-solid separator. The separated gas is transported to the high-temperature heat exchanger, while the fly ash is sent back to the gasifier to participate in the reaction again. The solid residues generated during the gasification process, such as ash and incompletely reacted carbon particles, are discharged from the gasifier through the slag discharge system at the bottom of the gasifier.

[0082] Before the gasifying agent is introduced into the gasifier, it is firstly heat-exchanged with the gas discharged from the gasifier in the high-temperature heat exchanger, and then the gasifying agent is preheated. In this embodiment, the gasifying agent is water vapor.

[0083] The above serial numbers (1), (2), and (3) are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating a specific order or primary and secondary relationship of the indicated technical features.

[0084] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A plasma gun assisted biomass and / or coal gasification device, characterized in that: It comprises a gasifier, and a plasma gun is arranged on the side of the gasifier.

2. The plasma gun assisted biomass and / or coal gasification device according to claim 1, characterized in that: The plasma gun is arranged in multiple stages; Optionally, the plasma gun includes a primary plasma gun and a secondary plasma gun; Optionally, the height h1 of the primary plasma gun is greater than the height h2 of the secondary plasma gun.

3. The plasma gun assisted biomass and / or coal gasification device according to claim 2, characterized in that: The height h1 of the primary plasma gun is 0.06h-0.35h, where h is the height of the gasifier; and / or The height h2 of the secondary plasma gun is 0.03h-0.25h.

4. The plasma gun assisted biomass and / or coal gasification device according to any one of claims 1 to 3, characterized in that: The gasification device also includes a biomass feeding device and a coal powder feeding device; A pulverized coal inlet and a biomass inlet are disposed opposite to each other on the side of the gasifier, a pulverized coal feeding device is connected to the pulverized coal inlet, and a biomass feeding device is connected to the biomass inlet; Preferably, the height of the coal powder inlet is h3, the height of the biomass inlet is h4, h is the height of the gasifier, and h3-h4=0-0.2h; More preferably, h3-h4=0~0.05h.

5. The plasma gun assisted biomass and / or coal gasification device according to claim 4, characterized in that: At least one of the following conditions is met: (1) h3 is 0.1h to 0.6h, preferably 0.3h to 0.6h; (2) h4 is 0.1h to 0.5h, preferably 0.3h to 0.5h.

6. The plasma gun assisted biomass and / or coal gasification device according to any one of claims 1 to 3, characterized in that: The biomass feeding device comprises a biomass hopper, a screw feeder, a tubular heater and a biomass conveying pipeline connected in sequence; Preferably, the tubular heater comprises a first heating section and a second heating section; the first heating section is a steam or gas heating section, and the second heating section is a plasma heating section.

7. The plasma gun assisted biomass and / or coal gasification device according to claim 6, characterized in that: The biomass conveying pipeline is inclined downward; Preferably, the biomass conveying pipeline forms an angle of 10° to 80° with the horizontal plane.

8. A method for gasifying biomass and / or coal, characterized in that: A device for gasifying biomass and / or coal using the plasma gun as described in any one of claims 1 to 7.

9. The gasification method according to claim 8, characterized in that: The following steps are involved: Biomass and / or pulverized coal are added to the gasifier, and a gasifying agent is introduced; the temperature in the gasifier is 800-1200°C, and the biomass and / or pulverized coal reacts with the gasifying agent to form raw coal gas; Preferably, the method further comprises separating the raw coal gas into gas and solid, conveying the separated gas to a high-temperature heat exchanger to preheat the gasifying agent to be introduced into the gasifier, and conveying the separated solid back to the gasifier.

10. The gasification method according to claim 9, characterized in that: The biomass is heated to 150-300°C in a tubular heater and then enters the gasifier.

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