Jacket type biomass downdraft gasifier

Abstract

The utility model discloses a jacket type biomass downdraft gasifier which comprises an upper barrel, a lower barrel and a hearth, an overturning fire grate is arranged at the bottom of the hearth; an upper barrel fuel gas interlayer and an air preheating interlayer are arranged in the upper barrel, and a lower barrel fuel gas interlayer is arranged in the lower barrel; a first-stage air distribution system is arranged between the air preheating interlayer and the upper barrel, and a second-stage air distribution system is arranged between the air preheating interlayer and the hearth. Biomass raw materials are sequentially subjected to drying, pyrolysis, oxidation and reduction in the hearth to generate high-temperature biomass fuel gas, most tar in the fuel gas can be cracked through the high reduction area temperature, and the ash content in the fuel gas can be further reduced through the fuel gas interlayer; according to the invention, efficient gasification of biomass is realized, clean biomass fuel gas with low tar and low dust is generated, efficient utilization of heat energy in the process is realized, the temperature of the fuel gas is reduced, and necessary conditions are provided for fuel gas purification and internal combustion engine power generation procedures.

Description

Technical Field

[0001] This application relates to the field of gasifier technology, specifically to a jacketed biomass downdraft gasifier. Background Technology

[0002] With the escalating global energy crisis and increasingly severe environmental pollution, biomass gasification power generation, as a clean and renewable energy technology, has received widespread attention. Biomass gasification power generation technology converts biomass into combustible gas, which is then used to drive gas-fired power generation equipment to generate electricity, offering the dual advantages of energy conservation, emission reduction, and economic viability. However, the development of this technology still faces some challenges and limitations.

[0003] First, the gas produced during biomass gasification power generation contains a certain amount of impurities, including ash, coke, tar, and acidic substances such as sulfur oxides, nitrogen oxides, and hydrogen chloride. These impurities need to be removed by a subsequent purification system to ensure the normal operation of the gas-fired power generation equipment. This process not only increases the complexity of the procedures but also raises the cost of equipment investment.

[0004] Secondly, biomass gasification furnaces currently experience problems such as low gasification efficiency, uneven burning, and slag coking during cooling. Internal combustion engines used for biomass gasification power generation have extremely high requirements for the cleanliness of the fuel gas, and the presence of any impurities may affect the performance and lifespan of the internal combustion engine.

[0005] In conclusion, biomass gasification power generation technology, as an important way to efficiently utilize biomass energy, has significant environmental and economic benefits, but its development is still limited by the technological maturity and economic viability of gasification and purification equipment. Utility Model Content

[0006] Therefore, this application provides a jacketed biomass downdraft gasifier to solve the problems of high requirements for gas cleanliness and increased costs caused by the generation of a certain amount of impurities in existing biomass gasification power generation technologies.

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] A jacketed biomass downdraft gasifier includes an upper cylinder and a lower cylinder arranged from top to bottom, with the upper cylinder and the lower cylinder having internal communication; the upper part of the upper cylinder and the lower cylinder are provided with a furnace for biomass reaction, and the top of the upper cylinder is provided with a feed inlet;

[0009] The bottom of the furnace is a rotating grate with several holes; the upper cylinder is provided with an upper cylinder gas jacket communicating with the furnace, and the lower cylinder is provided with a lower cylinder gas jacket communicating with the furnace; the upper cylinder gas jacket and the lower cylinder gas jacket are connected; the upper cylinder side wall near the upper end is provided with a gas outlet communicating with the upper cylinder gas jacket.

[0010] An air preheating jacket is provided inside the upper cylinder, and the air preheating jacket is located outside the gas jacket of the upper cylinder; a primary air distribution system is provided between the air preheating jacket and the upper cylinder, and a secondary air distribution system is provided between the air preheating jacket and the furnace, and the primary air distribution system is higher than the secondary air distribution system.

[0011] The lower cylinder is provided with an ash chamber, which is located below the rotating grate; the bottom of the ash chamber is provided with an ash discharge port.

[0012] Optionally, the primary air distribution system consists of multiple primary air ducts, and each primary air duct is equipped with a regulating valve.

[0013] Optionally, the secondary air distribution system consists of multiple secondary air ducts, which are not axially symmetrically distributed within the furnace.

[0014] Optionally, a water jacket is provided inside the lower cylinder, and the water jacket is located outside the gas jacket of the lower cylinder.

[0015] Optionally, the upper end of the upper cylinder is provided with an explosion vent.

[0016] Optionally, an ash chamber material level port is provided on the side wall near the upper end of the upper cylinder.

[0017] Optionally, both the upper and lower cylinders are provided with multiple temperature measuring ports at different heights, and the temperature measuring ports are connected to the furnace or ash chamber.

[0018] Optionally, a manhole door is fitted on the side wall of the lower cylinder.

[0019] Optionally, a pressure measuring port is provided on the upper cylinder.

[0020] Optionally, the upper cylinder is provided with a purge port, which is connected to the gas interlayer of the upper cylinder.

[0021] Compared with the prior art, this application has at least the following beneficial effects:

[0022] 1. Multi-stage uniform air distribution homogenizes the gasification environment within the furnace, reducing the possibility of uneven combustion and improving the gasification efficiency. The air preheating jacket increases the air temperature, enhancing the gasification effect to some extent and recovering waste heat from the high-temperature fuel gas. The fuel gas jacket also increases the path of gravity settling of the fuel gas, reducing the concentration of particulate matter in the fuel gas. The tar-rich fuel gas from the pyrolysis zone undergoes further cracking in the high-temperature reduction zone of the gasifier, significantly reducing the tar content in the outlet fuel gas. Through these settings, relatively clean biomass fuel gas production can be achieved, improving the gasification effect and thermal efficiency of the gasifier.

[0023] 2. The secondary air ducts are not axially symmetrically distributed, which can avoid air convection.

[0024] 3. By controlling the water jacket, the temperature of the outlet gas can be precisely controlled, providing the necessary conditions for subsequent gas purification and power generation processes.

[0025] 4. The manhole door facilitates necessary observation and maintenance operations inside the furnace. Attached Figure Description

[0026] To more intuitively illustrate the prior art and this application, exemplary drawings are provided below. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing this application; for example, based on the technical concept disclosed in this application and the exemplary drawings, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, size ratios, etc. of certain units (components).

[0027] Figure 1 This is a schematic diagram of the structure of a jacketed biomass downdraft gasifier provided in an embodiment of this application.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Furnace chamber; 2. Upper cylinder gas jacket; 3. Air preheating jacket; 4.1. First section flange; 4.2. Second section flange; 5. Lifting lug; 6. Explosion vent; 7. Feed inlet; 8. Gas outlet; 9. Level gauge port; 10. Primary air distribution system; 11. Pressure measuring port; 12.1. First temperature measuring port; 12.2. Second temperature measuring port; 12.3. Third temperature measuring port; 12.4. Fourth temperature measuring port; 12.5. Fifth temperature measuring port; 12 6. Sixth temperature measuring port; 13. Purge port; 14. Secondary air distribution system; 15. Lower cylinder gas jacket; 16. Water jacket; 17. Grate drive port; 18. Water inlet; 19. Water outlet; 20.1. First manhole; 20.2. Second manhole; 21. Ash tamping port; 22. Support structure; 23.1. First ash chamber material level port; 23.2. Second ash chamber material level port; 24. Tilting grate; 25. Ash chamber; 26. Ash discharge port. Detailed Implementation

[0030] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] In the description of this application: unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," "third," etc., in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (e.g., they should not be construed as an emphasis on importance or order). Expressions such as "comprising," "including," and "having" also mean "not limited to" (certain units, components, materials, steps, etc.).

[0032] The terms used in this application, such as "upper," "lower," "left," "right," and "middle," are generally used to indicate the general relative positional relationship for the purpose of intuitive understanding by referring to the accompanying drawings, and are not absolute limitations on the positional relationship in the actual product.

[0033] A jacketed biomass downdraft gasifier, referring to Figure 1 It includes an upper cylinder and a lower cylinder arranged from top to bottom, with the interiors of the upper and lower cylinders connected. A support structure 22 is provided at the bottom of the lower cylinder to support the entire gasifier.

[0034] Specifically, the upper cylinder and the lower cylinder are connected and fixed by the first segment flange 4.1 and the second segment flange 4.2 to facilitate disassembly, transportation and internal structure maintenance.

[0035] The gasifier has a furnace chamber 1 inside for biomass reaction. The furnace chamber 1 runs through the entire upper cylinder and extends from the bottom to the upper part of the lower cylinder. Correspondingly, a feed inlet 7 is provided at the top of the upper cylinder. The feed inlet 7 is connected to the furnace chamber 1 and is used to feed biomass raw materials. It can be connected to a silo or screw conveyor through its own flange to realize the feeding function.

[0036] The bottom of the furnace chamber 1 is a rotating grate 24. Biomass feed enters the furnace chamber 1 through the feed inlet 7 and falls onto the rotating grate 24. The rotating grate 24 is evenly provided with several holes and gaps for ash and slag discharge and gas passage. A grate drive port 17 is also provided at the rotating grate 24 for connection with the drive mechanism to provide power for driving the grate.

[0037] Furthermore, an explosion vent 6 is provided at the top of the upper cylinder. The explosion vent 6 is connected to an explosion venting device. When the gasifier operates abnormally or the pressure inside the furnace increases to the threshold, the explosion venting device is activated to achieve explosion venting.

[0038] An air preheating plate is installed inside the upper cylinder, and a water baffle is installed inside the lower cylinder. The upper cylinder gas jacket 2 is located between the air preheating plate and the furnace wall 1, and the lower cylinder gas jacket 15 is located between the water baffle and the furnace wall 1. The upper cylinder gas jacket 2, the lower cylinder gas jacket 15, and the interior of the furnace 1 are all interconnected. Correspondingly, an air outlet 8, communicating with the upper cylinder gas jacket 2, is provided on the side wall near the upper end of the upper cylinder for gas output.

[0039] An ash chamber 25 is provided inside the lower cylinder, and the ash chamber 25 is located below the tilting grate 24. An ash discharge port 26 is provided at the bottom of the ash chamber 25.

[0040] During implementation, the raw materials undergo drying, pyrolysis, oxidation, and reduction processes in the furnace chamber 1 to generate high-temperature biomass gas. The high-temperature gas passes through the rotating grate 24, ash chamber 25, lower cylinder gas jacket 15, and upper cylinder gas jacket 2 in sequence, and is finally discharged from the gasifier body through the gas outlet 8, so that the furnace chamber 1 is divided into reduction zone, oxidation zone, pyrolysis zone, and drying zone from bottom to top.

[0041] A water jacket 16 is located between the water baffle and the lower cylinder wall, outside the lower cylinder gas jacket 15. When the high-temperature gas passes through the ash chamber 25 and the lower cylinder gas jacket 15, it will exchange heat with the water in the water jacket 16 for the first time, cooling the gas and producing hot water as a byproduct.

[0042] The water jacket 16 is also provided with an inlet 18 and an outlet 19, wherein the inlet 18 is lower than the outlet 19. It should be noted that the medium in the water jacket 16 can also be replaced by other media that require heating in order to maximize the utilization of heat.

[0043] An air preheating jacket 3 is located between the upper cylinder wall and the air preheating layer, outside the upper cylinder gas jacket 2. When the gas enters the upper cylinder gas jacket 2, it undergoes a second heat exchange with the air in the air preheating jacket 3, heating the air and further cooling the gas to meet the requirements of subsequent gas purification and internal combustion engine power generation for low-temperature gas. The warmer air also acts as a vaporizing agent, improving the vaporization effect to some extent. Furthermore, as the gas passes through the lower cylinder gas jacket 15 and the upper cylinder gas jacket 2, some particulate matter settles out under gravity, improving the cleanliness of the gas.

[0044] A primary air distribution system 10 is provided between the air preheating jacket 3 and the upper cylinder, and a secondary air distribution system 14 is provided between the air preheating jacket 3 and the furnace 1. The primary air distribution system 10 is higher than the secondary air distribution system 14.

[0045] Specifically, the primary air distribution system 10 is located near the top of the upper cylinder and consists of multiple primary air ducts. Each primary air duct is also equipped with a regulating valve to control the air intake and optimize the gasification atmosphere inside the furnace. The secondary air distribution system 14 is arranged in the pyrolysis zone of the furnace 1 and consists of a ring of secondary air ducts evenly distributed around the gasifier furnace 1. This uniform air distribution effectively improves gasification efficiency and effect. To avoid air convection, an odd number of secondary air ducts are used so that they do not meet the symmetrical distribution condition in the circumferential direction.

[0046] The air entering the primary air distribution system 10 first enters the air preheating jacket 3, where it exchanges heat with the high-temperature gas in the upper cylinder gas jacket 2, increasing the air temperature and decreasing the gas temperature. This solves the problem of internal combustion engine power generation requiring low-temperature gas, and the high-temperature air, acting as a vaporizing agent, also helps improve the vaporization effect while reducing system heat loss. While the gas exchanges heat with the air in the upper cylinder gas jacket 2, some large particles such as fly ash also settle under gravity, reducing the difficulty of dust removal in subsequent stages.

[0047] Furthermore, a purge port 13 is provided on the upper cylinder, which is connected to the gas interlayer 2 of the upper cylinder, so that the gas interlayer can be purged and cleaned when necessary.

[0048] Since the furnace chamber 1 is always kept under a slight negative pressure during the operation of the gasifier, air can spontaneously enter the furnace chamber 1 through the primary air distribution system 10 and the secondary air distribution system 14, without the need for additional fans, which reduces the system energy consumption to a certain extent.

[0049] The ash produced after the biomass feedstock participates in the gasification reaction falls into the ash chamber 25 through the holes and gaps on the tilting grate 24. Correspondingly, the ash chamber 25 is also provided with a first ash chamber level port 23.1 and a second ash chamber level port 23.2. The first ash chamber level port 23.1 is higher than the second ash chamber level port 23.2, which is used to install level gauges to realize the timely and safe ash discharge of the ash chamber 25.

[0050] The ash chamber 25 is also equipped with an ash tamping port 21, which, together with the tilting grate 24, can effectively solve the problems of ash slag coking and agglomeration, ensure smooth slag discharge, and extend the continuous operation time of the gasifier.

[0051] The upper and lower cylinders are also equipped with several temperature measuring ports at different heights: the first temperature measuring port 12.1, the second temperature measuring port 12.2, the third temperature measuring port 12.3, the fourth temperature measuring port 12.4, the fifth temperature measuring port 12.5, and the sixth temperature measuring port 12.6. These temperature measuring ports can be connected to the furnace 1 or the ash chamber 25 to measure the temperature at different locations inside the gasifier.

[0052] A pressure measuring port 11 is also provided on the side wall near the top of the upper cylinder to assemble thermocouples and differential pressure transmitters, so as to realize real-time monitoring of the gasification environment inside the furnace.

[0053] Near the top of the upper cylinder, there is also a level gauge port 9, which is used to install a rotary paddle level gauge to ensure the monitoring and safety of the feed.

[0054] The lower cylinder is also equipped with a first manhole 20.1 and a second manhole 20.2 on its side wall for necessary observation and maintenance operations. The first manhole 20.1 is located near the bottom of the furnace 1, and the second manhole 20.2 is located near the top of the ash chamber 25.

[0055] To facilitate the hoisting of the gasifier, five lifting lugs are installed on the top of the upper cylinder.

[0056] The technical features of the above embodiments can be combined in any way (as long as there is no contradiction in the combination of these technical features). For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written should also be considered to be within the scope of this specification.

Claims

1. A jacketed biomass downdraft gasifier, characterized in that: It includes an upper cylinder and a lower cylinder arranged from top to bottom, and the upper cylinder and the lower cylinder are internally connected; a furnace (1) for biomass reaction is provided in the upper part of the upper cylinder and the lower cylinder, and a feed port (7) is provided at the top of the upper cylinder; The bottom of the furnace (1) is a rotating grate (24), which has several holes. The upper cylinder is provided with an upper cylinder gas jacket (2) that communicates with the furnace (1), and the lower cylinder is provided with a lower cylinder gas jacket (15) that communicates with the furnace (1). The upper cylinder gas jacket (2) and the lower cylinder gas jacket (15) are connected. The upper cylinder is provided with an outlet (8) that communicates with the upper cylinder gas jacket (2) on the side wall near the upper end. An air preheating jacket (3) is provided inside the upper cylinder, and the air preheating jacket (3) is located outside the gas jacket (2) of the upper cylinder; a primary air distribution system (10) is provided between the air preheating jacket (3) and the upper cylinder, and a secondary air distribution system (14) is provided between the air preheating jacket (3) and the furnace (1), and the primary air distribution system (10) is higher than the secondary air distribution system (14); The lower cylinder is provided with an ash chamber (25), which is located below the tilting grate (24); the bottom of the ash chamber (25) is provided with an ash discharge port (26).

2. The jacketed biomass downdraft gasifier according to claim 1, characterized in that: The primary air distribution system (10) consists of multiple primary air ducts, and each primary air duct is equipped with a regulating valve.

3. The jacketed biomass downdraft gasifier according to claim 2, characterized in that: The secondary air distribution system (14) consists of multiple secondary air ducts, which are not axially symmetrically distributed within the furnace (1).

4. The jacketed biomass downdraft gasifier according to claim 1, characterized in that: A water jacket (16) is provided inside the lower cylinder, and the water jacket (16) is located outside the gas jacket (15) of the lower cylinder.

5. The jacketed biomass downdraft gasifier according to claim 1, characterized in that: An explosion vent (6) is provided at the upper end of the upper cylinder.

6. The jacketed biomass downdraft gasifier according to claim 1, characterized in that: The upper cylinder has a ash chamber material level port on its side wall near the top.

7. The jacketed biomass downdraft gasifier according to claim 1, characterized in that: Both the upper and lower cylinders are equipped with multiple temperature measuring ports at different heights, and the temperature measuring ports are connected to the furnace (1) or the ash chamber (25).

8. The jacketed biomass downdraft gasifier according to claim 1, characterized in that: Manhole doors are installed on the side walls of the lower cylinder.

9. The jacketed biomass downdraft gasifier according to claim 1, characterized in that: A pressure measuring port (11) is provided on the upper cylinder.

10. The jacketed biomass downdraft gasifier according to claim 1, characterized in that: The upper cylinder is provided with a purge port (13), which is connected to the gas interlayer (2) of the upper cylinder.

Images