CN111253981B

CN111253981B - Grate system of biomass gasification furnace

Info

Publication number: CN111253981B
Application number: CN202010136318.8A
Authority: CN
Inventors: 刘跃伟
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-03-02
Filing date: 2020-03-02
Publication date: 2021-05-21
Anticipated expiration: 2040-03-02
Also published as: CN111253981A

Abstract

The invention discloses a biomass gasification furnace grate system which is arranged in a furnace body, wherein the gasification furnace grate system is sequentially provided with an air inlet pipe, a main air pipe, a branch air pipe and a main air pipe reinforcing pipe in a matching way from bottom to top, and the four parts form a grate body; the grate body is disc-shaped, and the fan-shaped gaps among the air inlet pipe, the main air pipe, the branch air pipes and the main air pipe reinforcing pipe are ash falling channels; split modular grates are covered on the air inlet pipe, the main air pipe, the branch air pipes and the main air pipe reinforcing pipe; the upper part of the grid top of the grid body is a ash layer with the thickness of not less than 200 mm. The volume of the dish-shaped grate is reduced by 5 times, the height is reduced by nearly 1 meter, the effective volume of a hearth can be improved by about 10 percent, and more RDF derived fuel can be consumed. The ash falling channels of the grate are increased, the ash falling section is increased by 2 times, the ash falling is more uniform, the collapse of the fixed carbon combustion layer is more uniform, and the possibility that the grate body is burnt by scorching carbon which is not uniformly collapsed is reduced.

Description

Grate system of biomass gasification furnace

Technical Field

The invention relates to a gasification furnace, in particular to a grate system of a biomass gasification furnace.

Background

The biomass waste gasification application technology has a development history in China for nearly thirty years, and has no commercial use for two reasons: low heat value and complex nature. Aiming at the gasification application technology, the combustible gas has low heat value and poor pyrolysis and gasification performance.

The biomass gasification furnace grate adopts the coal gasification furnace grate scheme, namely a conical grate body, which has large volume, high grate body, single ash falling channel and single air outlet, and further has the following problems:

1. in order to protect the grid body from being burnt, ash must be higher than the top of the grid body by more than 200mm, the effective volume of the gasification furnace is reduced due to the large volume and high height of the grid body, and more RDF cannot be consumed.

2. The height drop of the air outlet of the conical grid body is large, the thickness of the ash layer penetrated by the air is thick, so that the ash rising amount is large, the ash amount in the gasified and mixed combustible gas is large, and pressure is brought to the subsequent purification process.

3. The burning of the furnace grate is a common fault of the gasification furnace, and the burning of the cone top of the cone-shaped grate body is characterized. The burning of the cone top means that the whole grid body needs to be replaced, and the cost is not lower than 15 ten thousand.

4. If the air outlet of the conical grid body is large, the possibility of ash backflow is high, and blowing needs to be carried out at a higher wind speed; if the air outlet is made smaller, the cost is high, and the two methods are difficult to be completed.

5. The air outlet of the conical grid body has large required air quantity and uneven air outlet due to the characteristics of height and single shape, so that the fixed carbon combustion layer is not uniformly combusted, and simultaneously, ash is not uniformly dropped, so that the thermal ignition reduction rate of ash is high; the incomplete combustion of the fixed carbon can lead to unstable physicochemical properties of ash slag, and heavy metals can not be completely melted and passivated.

Another reason why the biomass gasification furnace grate scheme continues to be used for the coal gasification furnace grate is that biomass waste, particularly municipal domestic garbage, is complex in components, high in large-particle inorganic matter content, and not subjected to fine processing, is not gasified and combusted completely in a hearth, ash residues are easy to agglomerate and block, ash cannot be discharged, and further manual ash discharge during furnace shutdown is caused, and loss is very large.

The biomass waste comprises municipal domestic waste, municipal sludge, agricultural and forestry waste, medical waste, industrial organic waste and the like, and the equivalent of the biomass waste is more than 8 times of energy used by all human beings. The waste is subjected to multistage crushing, winnowing and magnetic separation to a particle size below 1 cm, then a biological pyrolysis deodorant is added (the core technology of the additive is to improve the pyrolysis performance of the biomass waste), and the mixture is fully stirred and pressed to form biomass Derived Fuel RDF (called refined purified Fuel for short), wherein the RDF has the characteristics of low particle size, high homogenization degree, high density, low content of non-combustible inorganic substances, high heat value, stable heat value, full pyrolysis, thorough gasification, stable combustion, no odor, ultralow emission of dioxin substances after gasification power generation and the like.

The stable mass production of biomass waste derived fuel (RDF) solves the problems of fine particles and homogenization; the problems of pyrolysis gasification and incomplete combustion are solved, the biomass waste recycling utilization is undoubtedly brought into the way of being fresh, the biomass waste recycling utilization device becomes a new growth point in the gasification application field, and the possibility is provided for the fine design of a grate system of a biomass gasification furnace.

Disclosure of Invention

The invention aims to overcome the defects of few grid air outlets, uneven air outlet distribution and large air outlet height difference in the background technology; the defects of crowded falling ash caused by small sectional area of the falling ash and local quick and slow falling ash in the background technology are overcome; the defect that the heat burning reduction rate is high in the background technology is overcome; the problem that the heavy metal content of the ash slag exceeds the standard in the background technology is solved. Therefore, a novel biomass gasification furnace grate system is provided.

In order to achieve the purpose, the invention provides the following technical scheme:

a biomass gasification furnace grate system is arranged in a furnace body, the gasification furnace grate system is sequentially provided with an air inlet pipe, a main air pipe, a branch air pipe and a main air pipe reinforcing pipe in a matching way from bottom to top to form a grate body, and the grate body is fixedly welded on the inner furnace bottom surface of the furnace body; the grate body is disc-shaped, the air inlet pipe vertically penetrates through the lower side of the furnace body and is communicated with a main air pipe horizontally arranged at the bottom end of the furnace body, and the main air pipe uniformly emits outwards around the air inlet pipe; the annular branch air pipes on the same horizontal plane with the main air pipe take the air inlet pipe as an axis and are communicated with the main air pipe; the extension part of the main air pipe at the periphery of the branch air pipe is a main air pipe reinforced pipe, and the main air pipe reinforced pipe extends to a furnace body water jacket on the inner wall of the furnace body; the fan-shaped gaps among the air inlet pipe, the main air pipe, the branch air pipes and the main air pipe reinforcing pipe are ash falling channels; split modular grates are covered on the air inlet pipe, the main air pipe, the branch air pipes and the main air pipe reinforcing pipe; the lower end of the air inlet pipe is provided with an air inlet which is connected with a blower; the upper part of the grid top of the grid body of the furnace grid is an ash layer with the thickness of not less than 200 mm.

The two sides of the grate body are uniformly provided with an upper air outlet and a lower air outlet; the top of the split modular grate adopts a pointed top design, air outlets are arranged at two sides of the split modular grate, and the air outlets of the split modular grate correspond to the air ports of the grate body; and air outlets of the split modular grates of the upper covers of the branch air pipes uniformly output air in a clockwise or anticlockwise direction.

The width X of the main air pipe and the width X of the branch air pipes are both 150 +/-15 mm; the height Y of the grate body is 200 mm-250 mm.

According to the diameter of the furnace body, the branch air pipes of the grid body can be made into a ring or a plurality of rings.

The distance between the outer wall of the air inlet pipe and the inner annular wall of one ring of the grid body of the grate is 350 +/-35 mm, the distance between the corresponding annular walls of the two rings of the branch air pipes is 350 +/-35 mm, and the optimal distance between the outer annular wall of the outermost ring of the branch air pipe and the inner wall of the hearth is 250 +/-25 mm.

The height of the split modular grate can be increased, and the air outlets on the two sides of the split modular grate can be increased.

The horizontal shortest distance between the air outlets on the two sides of the split modular grate and the air inlet of the grate body is larger than 1-1.5 times of the height of the air outlet, and the width of the air outlet is smaller than or equal to the width of the air inlet.

The air outlet of the split modular grate inclines downwards 0-30 degrees compared with the air port of the grate body, namely the lower edge of the air outlet of the split modular grate is below the horizontal line of the lower edge of the air port of the grate body, the horizontal included angle is 0-30 degrees, the upper edge of the air outlet of the split modular grate is below the horizontal line of the upper edge of the air port of the grate body, and the horizontal included angle is 0-30 degrees.

The grate body is made of common temperature-resistant materials, and the split modular grate is made of 1200-DEG C temperature-resistant materials.

The pipe wall distance R1 between the inner branch air pipe and the outer branch air pipe, the distance R2 between the outer pipe wall of the outer branch air pipe and the inner wall of the furnace body, and the ratio R1 between the two: r2 is not more than 1.8:1 and not less than 1.2: 1.

Compared with the prior art, the invention has the beneficial effects that:

1. as shown in FIG. 7, which is a schematic view of a conventional grate structure, the volume of the disc-shaped grate body is reduced by 5 times, the height is reduced by nearly 1 meter, the effective volume of a hearth can be increased by about 10 percent, and more RDF derived fuel can be consumed.

2. The ash falling channels of the grate body are increased, the ash falling cross section is increased by 2 times, the ash falling is more uniform, the collapse of the fixed carbon combustion layer is more uniform, and the possibility that the grate body is burnt by scorching carbon which is not uniformly collapsed is reduced.

3. The height drop of the air outlet of the split modular grate is 3 times smaller than that of the air outlet of the conical grate body, the combustion improver (wind) penetrates through the ash layer to be thin, the basic wind speed can be further reduced, the ash content (ash content) in gasified combustible gas can be effectively reduced, and the subsequent purification process reduces the treatment cost.

4. The air outlet increases nearly 4 times, highly reduces 2/3, and the air outlet arranges the dispersion evenly, and the penetrability of wind has improved about 2 times, and then the combustion stratum receives the wind evenly, and the burning is abundant, and the combustion stratum slump is even in addition, and then the hot ignition rate can be following 5% ~ 8%.

5. The air outlet is uniform, the combustion layer is collapsed uniformly, the combustion is sufficient, and the tar is sufficiently combusted in the fixed carbon combustion layer, so that the temperature of the fixed carbon combustion layer can be ensured to be over 1200 ℃, heavy metals in ash are completely melted and passivated, the physicochemical property of the ash is stable, and conditions are created for the comprehensive utilization of slag.

6. The fixed carbon combustion layer is uniformly blown, fully combusted, uniformly collapsed and low in heat ignition loss rate, so that the biomass waste derived fuel (RDF) can be fully utilized, the waste is reduced, and the output of combustible gas or the output of hydrogen is improved.

7. The burning of the grate body is related to the furnace application process and is a common fault of the gasification furnace. The falling ash is uniform, the collapse of the combustion layer is uniform, the grid top of the grid body of the furnace grid can be effectively prevented from being burnt, if the grid top of the grid body of the furnace grid is damaged, the replacement cost can be reduced by 3 times.

8. The combustion speed and the gasification speed of RDF can be effectively improved by the factors of sufficient combustion, increased ash falling channels, increased ash falling section and the like, and the unit consumption of the biomass waste is further improved.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a top plan view in horizontal section and a partial top plan view of the grate body of the present invention;

FIG. 3 is a schematic view of a split modular grate configuration of the present invention;

FIG. 4 is a schematic front view of the split modular grate of the present invention in expanded elevation;

FIG. 5 is an enlarged schematic view of the tuyere of the present invention;

FIG. 6 is a schematic view of the primary air duct of the present invention;

fig. 7 is a schematic view of a conventional art grid structure.

In the figure: 16. the furnace comprises an air inlet pipe, 17 main air pipe reinforcing pipes, 18 main air pipes, 19 branch air pipes, 20 grid tops, 21 ash layers, 25 furnace bodies, 26 furnace body water jackets, 29 split modular grids, 30 air ports and 31 air outlets.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 to 6, a biomass gasification furnace grate system is arranged in a furnace body 25, the gasification furnace grate system is sequentially provided with an air inlet pipe 16, a main air pipe 18, a branch air pipe 19 and a main air pipe reinforcing pipe 17 from bottom to top in a matching manner to form a grate body, and the grate body is fixedly welded on the inner furnace bottom surface of the furnace body 25; the grate body is disc-shaped, the air inlet pipe 16 is vertically arranged at the lower side of the furnace body 25 and is communicated with the main air pipe 18 horizontally arranged at the upper end of the air inlet pipe, and a plurality of main air pipes 18 are arranged in a crossed manner; the annular branch air pipe 19 on the same horizontal plane with the main air pipe 18 takes the air inlet pipe 16 as an axis and is communicated with the main air pipe 18; the extension part of the main air pipe 18 at the periphery of the branch air pipe 19 is an air pipe reinforced pipe 17, and the air pipe reinforced pipe 17 extends to a furnace body water jacket 26 on the inner wall of a furnace body 25; the fan-shaped gaps among the air inlet pipe 16, the main air pipe 18, the branch air pipes 19 and the main air pipe reinforcing pipe 17 are ash falling channels; the air inlet pipe 16, the main air pipe 18, the branch air pipes 19 and the main air pipe reinforced pipe 17 are all covered with split modular grates 29; the lower end of the air inlet pipe 16 is provided with an air inlet which is connected with a blower; the upper part of the grid top 20 of the grid body of the furnace is an ash layer 21 with the thickness not less than 200mm after RDF (refuse derived Fuel) is combusted.

The grate body is divided into an upper layer of tuyere 30 and a lower layer of tuyere 30, and is uniformly distributed on the side surface of the grate body; the branch air pipes 19 of the grid body can be made into a ring or a plurality of rings according to the diameter of the furnace body 25. The air outlet 31 of the split modular grate 29 of the upper cover of the main air pipe 18 in the first ring corresponds to the direction of the inner side air port 30 in the first ring, the air outlet 31 of the split modular grate 29 of the upper cover of the main air pipe 18 in the second ring corresponds to the direction of the outer side air port 30 in the first ring, and the like; the main air pipe 18 is extended to the reinforced section of the inner wall of the furnace body and can be directly made into a tip which is firmly welded with the inner wall of the hearth without an air outlet.

The split modular grate 29 is sleeved on the grate body by adopting a split modular cover plate design; the split modular grate 29 adopts a pointed top design at the top, and air outlets 31 are arranged on two sides of the split modular grate 29. An air outlet 31 of the split modular grate 29 corresponds to an air port 30 of the grate body; and the air outlets 31 of the split modular grates 29 covered on the branch air pipes 19 uniformly discharge air in a clockwise or anticlockwise direction. Corresponding to the biomass derived fuel RDF with high density and high fuel value, the air outlet needs to be increased, but the air speed is prevented from being increased, the height of the side surface of the split modular grate 29 is only required to be increased, a row of horizontal air outlets 31 are added, and the corresponding grate body does not need to be increased.

The width X of the grate body of the grate is a fixed value, the optimal embodiment is 150mm, and the width X of the main air pipe 18 and the width X of the branch air pipes 19 are equivalent according to the requirements of convenience and strength of the process; the height Y of the grid body is a variable and depends on the horizontal row number of the air ports, the air quantity requirement, the size of the air ports, the distance between the air ports and the short edges, the distance between the short edges of the air ports and the upper and lower edges of the grid body and the thickness of the grid body, the grid body can bear the weight of the fuel of the hearth under the limit condition, the best embodiment is that two rows of air ports are arranged up and down in the height direction of the grid body, and the best embodiment of the height Y is 200 mm-250 mm; the air inlet pipe of the grid body is divided into three sections, the lower section of the air inlet pipe is connected with a fan, the inner diameter of the middle section is not less than 250mm, the air inlet pipe is welded on the outer bottom surface of the furnace body, the inner diameter of the inner section of the hearth is between 250mm and 400mm, the air inlet pipe can be directly made into a sharp top without an air port because the temperature of the center of the hearth is higher and the wind receiving probability is higher; the grate body is made of common temperature-resistant materials, and all connecting parts are fully welded.

The grate body is provided with at least one ring of branch air pipes which can be designed into a plurality of rings according to the size of the furnace, the reasonable distance is 350 +/-35 mm between the outer wall of the air inlet pipe and the inner ring wall of one ring, 350 +/-35 mm between the opposite ring walls of the two rings and 250 +/-25 mm between the outer ring wall of the outer ring and the inner wall of the hearth according to the design basis of the number of the air outlets, the distribution of the air outlets, the possible ash-rising amount of the ash slag penetrated by the air, the air quantity required by a combustion layer, the homogenization degree of RDF and the like. The optimal embodiment of the main air pipes of the grate body is six, the main air pipes surround the air inlet pipe and are uniformly emitted outwards, and the requirements of balanced air outlet, load bearing, ash discharge and ash knife manhole arrangement can be met; the branch air pipe is surrounded on the main air pipe.

The split modular grate 29 adopts a split modular cover plate design and is downwards sleeved on the grate body; the top of the split modular grate 29 adopts a pointed design; the inner opening of the air outlet 31 corresponds to the grate body air opening 30, and the air outlet can be arranged at the top as required or not; the top adopts a sharp top to cut and guide ash; in consideration of cost, the top can be covered with a high-temperature-resistant and wear-resistant movable peak so as to reduce the material cost and the replacement cost of the grate body; the horizontal shortest distance between the air outlet 31 of the split modular grate 29 and the air inlet 30 is greater than 1-1.5 times of the height of the air outlet 31; the air outlet of the split modular grate inclines downwards 0-30 degrees compared with the air port, namely the lower edge of the air outlet 31 of the split modular grate 29 is below the horizontal line of the lower edge of the air port 30, the horizontal included angle is 0-30 degrees, the upper edge of the air outlet 31 of the split modular grate 29 is below the horizontal line of the upper edge of the air port 30, and the horizontal included angle is 0-30 degrees; the split modular grate 29 is made of 1200 ℃ temperature resistant materials, if a grate top protective sleeve is additionally arranged at the top, the grate top protective sleeve is made of 1200 ℃ temperature resistant materials, and the split modular grate 29 is made of common temperature resistant materials.

The tube wall distance R1 between the inner branch duct 19 and the outer branch duct 19, the distance R2 between the outer tube wall of the outer branch duct 19 and the inner wall of the furnace body 25, and the ratio R1: r2 is not more than 1.8:1 and not less than 1.2:1

The weight of the RDF fuel is calculated by 30 tons when the diameter of the gasification furnace is 3.2 meters, the weight of the RDF fuel is calculated by 40 tons when the diameter of the gasification furnace is 4.2 meters, and the grate body can bear the weight of the hearth fuel under the limit condition.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. The utility model provides a biomass gasification stove grate system, sets up in furnace body (25), its characterized in that: the gasification furnace grate system is sequentially provided with an air inlet pipe (16), a main air pipe (18), a branch air pipe (19) and a main air pipe reinforcing pipe (17) in a matching way from bottom to top to form a grate body, and the grate body is fixedly welded on the inner furnace bottom surface of a furnace body (25); the grate body is disc-shaped, the air inlet pipe (16) vertically penetrates through the lower side of the furnace body (25) and is communicated with a main air pipe (18) horizontally arranged at the bottom end of the furnace body (25), and the main air pipe (18) uniformly emits outwards around the air inlet pipe (16); the annular branch air pipe (19) on the same horizontal plane with the main air pipe (18) takes the air inlet pipe (16) as an axis and is communicated with the main air pipe (18); the extension part of the main air pipe (18) at the periphery of the branch air pipe (19) is a main air pipe reinforced pipe (17), and the main air pipe reinforced pipe (17) extends to a furnace body water jacket (26) on the inner wall of a furnace body (25); the fan-shaped gaps among the air inlet pipe (16), the main air pipe (18), the branch air pipes (19) and the main air pipe reinforcing pipe (17) are ash falling channels; split modular grates (29) are covered on the air inlet pipe (16), the main air pipe (18), the branch air pipes (19) and the main air pipe reinforcing pipe (17); the lower end of the air inlet pipe (16) is provided with an air inlet which is connected with a blower; the upper part of the grid top (20) of the grid body of the furnace grid is provided with an ash layer (21) with the thickness of not less than 200 mm;

the two sides of the grate body are uniformly provided with an upper air outlet and a lower air outlet (30); the top of the split modular grate (29) adopts a pointed top design, air outlets (31) are arranged on two sides of the split modular grate (29), and the air outlets (31) of the split modular grate (29) correspond to air ports (30) of the grate body; and air outlets (31) of the split modular grates (29) covered on the upper side of the branch air pipes (19) uniformly discharge air in a clockwise or anticlockwise direction.

2. The biomass gasifier grate system of claim 1, wherein: the width X of the main air pipe (18) and the width X of the branch air pipes (19) are both 150 +/-15 mm; the height Y of the grate body is 200 mm-250 mm.

3. The biomass gasifier grate system of claim 1, wherein: the branch air pipes (19) of the grate body can be made into a ring or a plurality of rings according to the diameter of the furnace body (25).

4. The biomass gasifier grate system of claim 3, wherein: the distance between the outer wall of the air inlet pipe (16) and the inner annular wall of one ring of the grate body is 350 +/-35 mm, the distance between the corresponding annular walls of the two rings of the branch air pipe (19) is 350 +/-35 mm, and the optimal distance between the outer annular wall of the outermost ring of the branch air pipe (19) and the inner wall of the hearth is 250 +/-25 mm.

5. The biomass gasifier grate system of claim 1, wherein: the height of the split modular grate (29) can be increased, and the air outlets (31) on two sides of the split modular grate (29) can be increased.

6. The biomass gasifier grate system of claim 1, wherein: the horizontal shortest distance between the air outlets (31) on the two sides of the split modular grate (29) and the air inlet (30) of the grate body is larger than 1-1.5 times of the height of the air outlet (31), and the width of the air outlet (31) is smaller than or equal to the width of the air inlet (30).

7. The biomass gasifier grate system of claim 1, wherein: the air outlet (31) of the split modular grate (29) inclines downwards 0-30 degrees compared with the air port (30) of the grate body, namely the lower edge of the air outlet (31) of the split modular grate (29) is below the horizontal line of the lower edge of the air port (30) of the grate body, the horizontal included angle is 0-30 degrees, the upper edge of the air outlet (31) of the split modular grate (29) is below the horizontal line of the upper edge of the air port (30) of the grate body, and the horizontal included angle is 0-30 degrees.

8. The biomass gasifier grate system of claim 1, wherein: the grate body is made of common temperature-resistant materials, and the split modular grate (29) is made of 1200-DEG C temperature-resistant materials.

9. The biomass gasifier grate system of claim 3, wherein: the pipe wall distance R1 between the inner branch air pipe (19) and the outer branch air pipe (19), the distance R2 between the outer pipe wall of the outer branch air pipe (19) and the inner wall of the furnace body (25), and the ratio R1 between the two: r2 is not more than 1.8:1 and not less than 1.2: 1.