Downdraft gasification furnace adopting transverse groove water-cooled anti-slagging fire grate

Abstract

The utility model discloses a downdraft gasifier adopting a transverse groove water-cooled anti-slagging grate, which relates to the technical field of gasifiers and comprises a gasifier body, a drying layer, a dry distillation layer, an oxidation layer and a reduction layer are sequentially arranged in the gasifier body from top to bottom, a gas outlet is arranged on the lower portion of the gasifier body, an ash hopper is arranged below the gasifier body, and an ash discharge port is arranged on the ash hopper. 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; according to the utility model, a water-cooling mode is adopted to dissipate heat of the fire grate, the heat dissipation effect is good, and the problem of high-temperature slagging in an oxidation area can be effectively prevented; 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 downdraft gasifier adopting a transverse groove water-cooled anti-slagging grate. 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 gasifiers remains a pain point and difficult problem in this field. Utility Model Content

[0004] The purpose of the utility model is to provide a downdraft gasifier adopting a transverse groove water-cooled anti-slagging grate, which adopts a water-cooling method to dissipate heat from the grate, has a good heat dissipation effect, and can effectively prevent the high-temperature slagging problem in the oxidation zone; at the same time, the grate can rotate, which is convenient for 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, which 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.

[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 along the tangent direction of the grate at that location.

[0008] Preferably, a plurality of grooves are provided at intervals on the surface of the grate, and the grooves are arranged transversely on the side walls 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, the grate as a whole is movably mounted on a bearing, 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 a transverse groove water cooling method. 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. The grooves are arranged on the side wall of the grate at intervals along the outlet direction of the gasification air outlet. The grooves guide the air. The outside of the gasification air outlet is provided with a baffle. The baffle is arranged along the tangential direction of the grate at that location, so that the gasification air is blown out along the tangential direction of the grate. Under the action of the groove diversion, the gasification air is blown out from the groove on the surface of the grate along the direction of the gasification air. The air is blown out evenly in the direction close to the grate surface, forcing more air to flow through the annular area on the fuel side close to the grate surface, thereby forcing the annular 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 in this area facilitates rapid cooling by the grate, preventing the fuel from generating high-temperature slagging. This avoids the traditional gasification furnace where the gasification air is blown in a direction perpendicular to the grate surface, causing high temperature in the area far from the grate surface, unable to dissipate heat in time, and causing 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. 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

[0015] Figure 1 This is a structural schematic diagram of a downdraft gasifier using a transverse groove water-cooled anti-slagging grate according to the present invention;

[0016] Figure 2 for Figure 1 Cross-sectional view at AA in the middle;

[0017] Figure 3 Schematic diagram of the structure of the grate;

[0018] Figure 4 for Figure 3 Enlarged view of point B in the middle;

[0019] Figure 5 The figure shows the air flow direction and temperature distribution of the traditional grate.

[0020] Figure 6 This is a schematic diagram of the air flow direction and temperature after the air is forced to turn by the transverse groove water-cooled anti-slagging grate used in this patent.

[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; 13. Bearing; 14. Push rod; 15. Guide sleeve; 16. Crank connecting rod; 17. Reciprocating motor; 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 downdraft gasifier adopting the transverse groove water-cooled anti-slagging grate of the present invention during normal operation, and do not limit the orientations during storage and transportation. They only represent relative position relationships, not absolute position relationships.

[0024] like Figures 1 to 3 As shown together, a downdraft gasifier using a transverse groove water-cooled anti-slagging grate 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 may also be rectangular, square, or other shapes as needed. Accordingly, the gasification air passage 701 and the water cooling passage 702 within the grate 7 are also annular in structure. Several grates 7 of increasing diameter are concentrically arranged, with an annular gap formed between adjacent grates 7 for placing the fuel 32.

[0027] The gasification air channel 701 is provided with a gasification air outlet 703, and 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; 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 Figures 4 to 6As shown, the surface of the grate 7 is provided with a plurality of grooves 705 at intervals. The grooves 705 are arranged horizontally on the side wall of the grate 7 and form a ring on the side wall of the grate 7 along the outlet direction of the gasification air outlet 703. The grooves 705 guide the air. Preferably, in this embodiment, the gasification air outlet 703 is arranged at a 45-degree angle to the tangent of the grate 7 at that location. A deflector 704 is provided on the outside of the gasification air outlet 703. The deflector 704 is arranged along the tangent direction of the grate 7 at that location, so that the gasification air is blown out along the tangential direction of the grate 7. Under the guidance of the grooves 705, the gasification air is blown out from the grooves 705 on the surface of the grate 7. The air is blown out evenly in the direction close to the surface of the grate 7, so that more air is forced to flow through the annular area close to the surface of the grate 7 on the side of the fuel 32, thereby forcing the annular 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 is convenient for being quickly cooled by the grate 7 to prevent the fuel 32 from generating high-temperature slagging. It avoids the situation in which the gasification wind is blown out in a direction perpendicular to the surface of the grate 7 as in a traditional gasifier, 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. The grate as a whole is movably installed on the bearing 13. 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 with a guide 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. 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 downdraft gasification furnace using a transverse groove water-cooled anti-slagging grate, 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 bottom 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 closely 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 baffle (704) is provided on the outside of the gasification air outlet (703), and the baffle (704) is arranged along the tangent direction of the grate (7) at that location; a plurality of grooves (705) are provided at intervals on the surface of the grate (7), and the grooves (705) are arranged transversely on the side wall of the grate (7).

2. A downdraft gasifier using a transverse groove water-cooled anti-slagging grate 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 downdraft gasifier using a transverse groove water-cooled anti-slagging grate 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.

4. The downdraft gasifier using a transverse groove water-cooled anti-slagging grate 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 assembly. The grate assembly is movably mounted on a bearing (13). The grate assembly is connected to a power device capable of driving the grate (7) to rotate.

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