Water-cooling anti-slagging air inlet structure suitable for downdraft biomass gasifier

Abstract

The utility model discloses a water-cooling anti-slagging air inlet structure suitable for a downdraft biomass gasification furnace, which relates to the technical field of gasification furnaces and comprises a furnace body, a drying layer, a dry distillation layer, an oxidation layer and a reduction layer are sequentially arranged in the furnace body from top to bottom, the lower part of the furnace body is provided with a fuel gas outlet, an ash hopper is arranged below the furnace body, and the ash hopper is provided with an ash discharge port; the gasification furnace further comprises a hopper connected with a feeding device, and is characterized in that a fire grate is installed in the furnace body and provided with a gasification air channel and a water cooling channel, the gasification air channel is provided with a gasification air outlet, and an inlet of the gasification air channel is communicated with an air blower; the water-cooling channel is tightly attached to the side part of the gasified air channel, an inlet of the water-cooling channel is communicated with the cooling water pump, and an outlet of the water-cooling channel is communicated with the water outlet pipe; the fire grate is cooled in a water-cooling mode, the heat dissipation effect is good, the longitudinal grooves are formed in the surface of the fire grate, and the problem of high-temperature slagging in an oxidation area can be effectively solved; and meanwhile, the fire grate can rotate, and slag breaking and slag discharging are facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of gasifiers, in particular to a water-cooled anti-slagging air inlet structure suitable for a downdraft biomass gasifier. Background Art

[0002] Biomass fuel is rich in alkali metals and alkaline earth metals. The direct impact of this is that the ash melting point of biomass fuel is often relatively low, which is particularly prone to slagging during direct combustion, gasification and other heat utilization processes. Moreover, if alkali metals enter the flue gas, they will also condense on the heating surface and cause hard ash accumulation that is difficult to clean, seriously affecting the heat transfer efficiency of the heat exchange tube bundle.

[0003] The advantages of downdraft biomass gasifiers are low tar content and high gas outlet temperature, so there are no problems with ignition and stable combustion when the gas is directly burned; however, how to suppress the slagging problem in the oxidation zone caused by high alkali metal content during the use of downdraft biomass gasifiers is still a pain point that needs to be solved during the promotion and utilization of downdraft gasifiers. Utility Model Content

[0004] The purpose of the utility model is to provide a water-cooled anti-slagging air inlet structure suitable for a downdraft biomass gasifier, which adopts a water-cooling method to dissipate heat from the grate, with good heat dissipation effect. The surface of the grate is provided with longitudinal grooves, which can effectively prevent the high-temperature slagging problem in the oxidation zone; at the same time, the grate can be rotated to facilitate slag breaking and slagging.

[0005] The utility model includes a furnace body, which is provided with a drying layer, a retorting layer, an oxidation layer and a reduction layer in sequence from top to bottom, a gas outlet is provided at the lower part of the furnace body, an ash hopper is provided below the furnace body, and the ash hopper is provided with an ash discharge port; it also includes a hopper, and the hopper is connected to a feeding device, and is characterized in that: a grate is installed in the furnace body, the grate is provided with a gasification air channel and a water cooling channel, the gasification air channel is provided with a gasification air outlet, and the inlet of the gasification air channel is connected to a blower; the water cooling channel is arranged closely to the side of the gasification air channel, the inlet of the water cooling channel is connected to a cooling water pump, and the outlet of the water cooling channel is connected to a water outlet pipe; a plurality of grooves are provided at intervals on the surface of the grate, and the grooves are vertically arranged on the side wall of the grate.

[0006] Preferably, the grate is annular, and a plurality of grates with successively increasing diameters are arranged concentrically, with an annular gap for placing fuel formed between two adjacent grates.

[0007] Preferably, a baffle is provided on the outer side of the gasification air outlet, and the baffle is arranged parallel to the side wall of the grate at that location.

[0008] Preferably, the gasification air outlet is provided with at least two layers, arranged along the longitudinal direction of the grate.

[0009] Preferably, each gasification air channel is provided with gasification air outlets on both the inner and outer sides, and each gasification air outlet passes through the water cooling channel and is in communication with the outside.

[0010] Preferably, a plurality of grates are serially connected from the inside to the outside to form a grate as a whole, and the grate as a whole is connected to a power device capable of driving the grate to rotate.

[0011] In summary, the present invention has the following beneficial effects:

[0012] 1. The grate is cooled by longitudinal groove water cooling. The gasification air channel is provided with a gasification air outlet connected to the annular gap between the grates. The surface of the grate is provided with grooves, which are vertically arranged on the side wall of the grate. The grooves guide the air. The outside of the gasification air outlet is provided with a baffle, which is parallel to the side wall of the grate at that location. The baffle has a deflecting effect on the airflow, so that after the gasification air is blown out from the gasification air outlet, it is deflected by the baffle and flows from the groove on the grate surface along the grate surface close to the grate surface. The air is blown out evenly in the direction of the grate, which forces more air to flow through the area on the fuel side close to the grate surface, thus forcing the area close to the grate surface to become the local highest temperature area in the furnace body. The water cooling channel closest to the grate facilitates rapid cooling of the area by the grate, preventing the fuel from generating high-temperature slagging. This avoids the situation in traditional gasifiers where the gasification air is blown out in a direction perpendicular to the grate surface, causing high temperature in the area far from the grate surface, and the cooling medium in the cooling channel cannot dissipate the heat in time, resulting in high-temperature slagging.

[0013] 2. Water cooling channels are provided on both sides of each gasification air channel. The cooling water in the water cooling channel can take away the heat from the grate surface, quickly reducing the temperature of the grate surface, resulting in faster cooling and better cooling effect.

[0014] 3. Compared with the horizontal grooves, the longitudinal grooves allow the gas to flow from top to bottom and finally be discharged through the gas outlet. The gas flow rate is faster and the gas circulation is better. The gas generated in the furnace body is more easily discharged from the gas outlet at the bottom, thereby improving work efficiency.

[0015] 4. The grate is driven by the power mechanism to make a rotating reciprocating motion along the tangential direction of the grate, thereby driving the grate to rotate. The rotation process can eliminate fuel bridging and facilitate slag breaking and ash discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic structural diagram of a water-cooled anti-slagging air inlet structure suitable for a downdraft biomass gasifier according to the present invention;

[0017] Figure 2 for Figure 1 Cross-sectional view at AA in the middle;

[0018] Figure 3 for Figure 1 Enlarged view of point B in the middle;

[0019] Figure 4 The figure shows the air flow direction and temperature distribution of the traditional grate.

[0020] Figure 5 This is a schematic diagram of the air outlet direction and temperature after the anti-slagging air inlet structure used in this patent forces the air to turn.

[0021] In the figure: 1. Furnace body; 2. Gas outlet; 3. Ash hopper; 4. Ash discharge port; 5. Hopper; 6. Feeding device; 7. Grate; 701. Gasification air channel; 702. Water cooling channel; 703. Gasification air outlet; 704. Baffle; 705. Groove; 8. Blower; 9. Cooling water pump; 10. Water outlet pipe; 11. Water inlet pipe; 12. Air inlet pipe; 14. Push rod; 15. Guide sleeve; 16. Crank connecting rod; 17. Reciprocating motor; 18. Guide rail; 19. Roller; 31. Cooling channel; 32. Fuel; 33. High temperature area. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings.

[0023] The orientations mentioned in this specification are based on the orientations of the water-cooled anti-slagging air inlet structure suitable for a downdraft biomass gasifier of the present invention during normal operation, and do not limit the orientations during storage and transportation. They only represent relative positional relationships, not absolute positional relationships.

[0024] like Figures 1 to 3 As shown together, a water-cooled anti-slagging air inlet structure suitable for a downdraft biomass gasifier includes a furnace body 1, in which a drying layer, a retorting layer, an oxidation layer and a reduction layer are arranged from top to bottom; a grate 7 is installed in the furnace body 1, and gaps between the grate 7 are provided with spaces for placing fuel 32, and the grate 7 is provided with a gasification air channel 701 and a water-cooling channel 702, the gasification air channel 701 is used to provide a gasifying agent for the gasifier, and the water-cooling channel 702 is used to cool the grate 7 to prevent the occurrence of high-temperature slagging.

[0025] It also includes a hopper 5, which is connected to a feeding device 6. The hopper 5 is used to store fuel 32. The biomass pellet fuel 32 enters the furnace body 1 through the feeding device 6 on the furnace top, and gradually moves downward as the fuel 32 is consumed. After passing through the drying layer and the retorting layer in sequence, it falls between the two adjacent circles of grates 7 in the oxidation layer, mixes with the gasifying agent, and burns, and then continues to move downward to the reduction layer. After burning out, it falls into the ash hopper 3 below the furnace body 1 through the gap between the grates 7 and is discharged through the ash discharge port 4; the gasifying agent enters the furnace body 1 through the gasification air channel 701 of the grate 7, and after mixing with the fuel 32, produces pyrolysis, oxidation, reduction and reforming reactions at high temperature. Through the action of the gasifying agent (such as air, oxygen or water vapor), the biomass polymer is decomposed to generate small molecular hydrocarbons, carbon monoxide, hydrogen, methane and other gases, which are output from the gas outlet 2 at the bottom of the furnace body 1 for use by subsequent equipment.

[0026] Preferably, in this embodiment, the grate 7 is annular. In other embodiments, the grate 7 can also be rectangular, square, or other shapes as needed; accordingly, the gasification air channel 701 and the water-cooling channel 702 arranged in the grate 7 are also annular structures; a number of grates 7 with successively increasing diameters are arranged concentrically, and an annular gap for placing the fuel 32 is formed between two adjacent grates 7.

[0027] The gasification air channel 701 is provided with a gasification air outlet 703, and the gasification air outlet 703 is arranged perpendicular to the gasification air channel 701. There are several gasification air outlets 703, which are arranged at intervals around the circumference of the gasification air channel 701, and pass through the water-cooling channel 702, and finally communicate with the annular gap between the grates 7; in the vertical direction, the gasification air outlet 703 is provided with no less than two layers; the inlet of the gasification air channel 701 is connected to the blower 8 through the air inlet pipe 12, providing gasification air for the grate 7. After being pressurized by the blower 8, the gasification air passes through the air inlet pipe 12, the gasification air channel 701 of the grate 7, and the gasification air outlet 703 in turn, and finally enters the annular gap between the grates 7. Under high temperature, the fuel 32 is decomposed, and the generated combustible gas flows downward and is then output through the gas outlet 2 at the lower part of the furnace body 1.

[0028] Furthermore, a plurality of gasification air outlets 703 are provided on both the inner and outer sides of each gasification air channel 701, and each gasification air outlet 703 passes through the water-cooling channel 702 and is connected to the outside world, so that gasification air is blown out from both the inner and outer sides of the grate 7, and the gasification air supply volume is larger and more uniform, and the gasification efficiency of the fuel 32 is higher; in particular, the grate 7 located at the outermost layer is only provided with the gasification air outlet 703 on the inner side of the grate 7.

[0029] like Figure 2 、 Figure 4 、 Figure 5As shown, the surface of the grate 7 is provided with a plurality of grooves 705 at intervals. The grooves 705 are vertically arranged on the side wall of the grate 7. The grooves 705 guide the air. A deflector 704 is provided on the outside of the gasification air outlet 703. The deflector 704 is arranged parallel to the side wall of the grate 7 at that location. The deflector 704 deflects the gasification air blown out from the gasification air outlet 703. As a result, after the gasification air is blown out from the gasification air outlet 703, it is uniformly diverted from the grooves 705 on the surface of the grate 7 along the direction close to the surface of the grate 7 under the deflection effect of the deflector 704. Blowing out causes more air to flow through the area on the side of the fuel 32 close to the surface of the grate 7, thereby forcing the area close to the surface of the grate 7 to become the local highest temperature area 33 in the furnace body 1. This area is closest to the water-cooling channel 702 of the grate 7, which facilitates rapid cooling by the grate 7 to prevent the fuel 32 from generating high-temperature slagging. It avoids the situation in a traditional gasifier where the gasification wind is blown in a direction perpendicular to the surface of the grate 7, thereby causing high temperature to be generated in the area far away from the surface of the grate 7, and the cooling medium in the cooling channel 31 cannot dissipate heat in time, resulting in high-temperature slagging.

[0030] The water-cooling channel 702 is arranged close to the side of the gasification air channel 701. The water-cooling channel 702 is divided into several discontinuous arc structures by several gasification air outlets 703, and the adjacent arc structures are connected to each other; the inlet of the water-cooling channel 702 is connected to the cooling water pump 9 through the water inlet pipe 11 to provide cooling water for the water-cooling channel 702, and the outlet of the water-cooling channel 702 is connected to the water outlet pipe 10 for collecting cooling water. The water-cooling channels 702 of each grate 7 are separately connected to the water inlet pipe 11 and the water outlet pipe 10, so that the circulation efficiency is higher.

[0031] Furthermore, each grate 7 is provided with two water cooling channels 702 , and the two water cooling channels 702 are distributed on the inner and outer sides of the gasification air channel 701 , so that the heat dissipation speed of the grate 7 is faster and the heat dissipation effect is better.

[0032] Furthermore, several grates 7 are connected in series from the inside to the outside to form a grate as a whole, a roller 19 is provided under the grate as a whole, a guide rail 18 is provided under the roller 19, and the guide rail 18 and the roller 19 support the grate as a whole; the side of the grate as a whole is connected to the straight push rod 14, the straight push rod 14 is connected to the outer sleeve 15, the straight push rod 14 is connected to the crank connecting rod 16, and the crank connecting rod 16 is connected to the reciprocating motor 17; the grate as a whole rotates and reciprocates along the tangential direction of the grate 7 under the push of the reciprocating motor 17, thereby driving the grate 7 to rotate, and the rotation process can eliminate the bridging of the fuel 32, which is convenient for slag breaking and ash discharge.

[0033] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A water-cooled anti-slagging air inlet structure suitable for a downdraft biomass gasifier, comprising a furnace body (1), wherein a drying layer, a retorting layer, an oxidation layer and a reduction layer are sequentially provided in the furnace body (1) from top to bottom, a gas outlet (2) is provided at the lower portion of the furnace body (1), an ash hopper (3) is provided below the furnace body (1), and the ash hopper (3) is provided with an ash discharge port (4); and further comprising a hopper (5), wherein the hopper (5) is connected to a feeding device (6), and is characterized in that: A grate (7) is installed in the furnace body (1), and the grate (7) is provided with a gasification air channel (701) and a water cooling channel (702), the gasification air channel (701) is provided with a gasification air outlet (703), and the inlet of the gasification air channel (701) is connected to the blower (8); the water cooling channel (702) is arranged close to the side of the gasification air channel (701), the inlet of the water cooling channel (702) is connected to the cooling water pump (9), and the outlet of the water cooling channel (702) is connected to the water outlet pipe (10); a plurality of grooves (705) are arranged at intervals on the surface of the grate (7), and the grooves (705) are arranged vertically on the side wall of the grate (7); a deflector (704) is provided on the outside of the gasification air outlet (703), and the deflector (704) is arranged parallel to the side wall of the grate (7) at that location.

2. The water-cooled anti-slagging air inlet structure suitable for a downdraft biomass gasifier according to claim 1, characterized in that: The grate (7) is annular, and a plurality of grates (7) with successively increasing diameters are arranged concentrically, with an annular gap for placing fuel (32) being formed between two adjacent grates (7).

3. The water-cooled anti-slagging air inlet structure suitable for a downdraft biomass gasifier according to claim 1, characterized in that: The gasification air outlet (703) is provided in no less than two layers and is arranged along the longitudinal direction of the grate (7).

4. The water-cooled anti-slagging air inlet structure suitable for a downdraft biomass gasifier according to claim 1, characterized in that: Each gasification air channel (701) is provided with a gasification air outlet (703) on both the inner and outer sides, and each gasification air outlet (703) passes through the water cooling channel (702) and is in communication with the outside.

5. The water-cooled anti-slagging air inlet structure suitable for a downdraft biomass gasifier according to claim 1, characterized in that: A plurality of grates (7) are sequentially connected in series from the inside to the outside to form a grate whole, and the grate whole is connected to a power device capable of driving the grate (7) to rotate.

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