CN111076163A

CN111076163A - Straw bundle burning boiler with reciprocating grate

Info

Publication number: CN111076163A
Application number: CN201911389540.2A
Authority: CN
Inventors: 刘圣勇; 张品; 王炯; 鲁杰; 张舒晴; 青春耀; 黄黎; 陶红歌; 李建宾; 张国艳; 马永涛
Original assignee: Henan Agricultural University
Current assignee: Henan Agricultural University
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-04-28

Abstract

The invention discloses a reciprocating grate straw bundle burning boiler, which comprises an upper boiler body, a middle hearth and a lower grate, wherein the hearth is of a multi-arch structure and comprises a front arch, a middle arch and a rear arch, a secondary air supply system is arranged on the front arch, the middle arch is a vertical downward fire-blocking wall, and the rear arch extends to the middle part of the hearth from the rear wall of the hearth; the furnace grate is a reciprocating grate, a furnace door is arranged on the furnace hearth and corresponds to the feeding end of the reciprocating grate, and an auxiliary feeding mechanism is arranged outside the furnace door in a matched manner; the grate is provided with a primary air supply system below, the primary air supply system comprises a plurality of air bins sequentially arranged along the advancing direction of the reciprocating grate, the air bins are connected with air supply pipelines, and each air bin is provided with an independent air adjusting device, so that a sectional type air supply mechanism is formed. The invention is suitable for the combustion of biomass straw bundled fuel, and effectively solves the problems of low mechanization degree, low thermal efficiency, difficult thorough burning of the bundled fuel, serious grate slagging, substandard smoke emission and the like of the original biomass boiler.

Description

Straw bundle burning boiler with reciprocating grate

Technical Field

The invention belongs to the technical field of combustion of biomass straw bundling fuel, and particularly relates to a reciprocating grate straw bundling boiler.

Background

The biomass straw resources in China are rich, and in recent years, the country gradually strengthens the comprehensive utilization of the straw, so that the straw is changed into valuables. The biomass energy is mainly utilized by direct combustion, gasification, liquefaction, anaerobic fermentation and other methods, the combustion is the most economic and effective method and is particularly suitable for the national conditions of China, and the biomass straw as the fuel has the advantages of high volatile content, easiness in combustion, relatively low content of harmful substances in smoke, low heat value, insufficient combustion, easiness in slag bonding and the like. The common bulk combustion has the problem of low efficiency, while the suspension combustion has higher requirement on the granularity of the fuel, the energy consumption of the formed fuel is larger, and the bundling combustion does not have the defects. The density of the bundling fuel is moderate, the transportation and the storage are convenient, the shape and the size of the fuel are different along with the difference of bundling machines, and the biomass straw bundling technology in developed countries such as Europe and America is developed earlier and is also applied to a certain extent.

The theoretical research and the application research on biomass straw bundling technology in China just start, the equipment for burning bundled straws is few, and a plurality of technical problems are yet to be solved. The combustion characteristics of the biomass bundled fuel are greatly different from those of fossil fuel, the biomass bundled fuel has high moisture content, and the generated volatile matter and flue gas have high flow rate and large volume, are difficult to fully combust and have high heat loss of the flue gas; when the biomass bundling fuel is combusted, the structure is loose, and the generated ash content can be blown by primary air and flows along with flue gas, so that the problem of serious ash deposition and blockage in a hearth is easily caused; the biomass has low calorific value and low ash melting point, the biomass is difficult to stably burn in a common boiler, and the serious slagging problem is caused by overhigh temperature, so that the heat transfer capacity of a heating surface is reduced.

Most of the prior domestic straw bundle burning boilers have low thermal efficiency and low mechanization degree, and the straw bundles are large and dense, are easy to burn and cannot penetrate so as to cause insufficient combustion, and have the problems of serious grate slagging, high smoke emission concentration, great influence on the environment and the like.

The invention with the publication number of CN110410773A discloses a combined grate environment-friendly industrial boiler for biomass direct-combustion, partition, grading and split-phase combustion, which comprises a boiler body shell, a hearth body, a combined grate, an air supply system, a feeding device, a distribution and blanking device and a flue gas recirculation system; the problem of low efficiency caused by coking in the prior art is solved: the temperature in the semi-gasification combustion zone can be controlled in a lower temperature range, the semi-gasification combustion zone can generate combustible gas and is not easy to coke, the semi-gasification combustion zone, the solid gas reinforced main combustion zone and the solid combustible combustion zone realize zoned, graded and split-phase combustion, the concentration of generated nitrogen oxides is low, and the environment-friendly effect is good; meanwhile, a semi-gasification combustion area is adopted, and a reciprocating grate pushes away and scatters fuel, so that the permeability of the burning biomass is excellent; the traveling grate stoker is matched with the solid gas reinforced main combustion area and the solid combustible combustion area to realize layer-by-layer combustion, and the running state of the whole machine is efficient and environment-friendly under the dispatching of the transverse air-equalizing and longitudinally-adjustable air supply system and the thermal control system of the combined grate.

Through analysis, the biomass direct-fired boiler and the straw bundle-fired boiler related to the combined grate environmental-friendly industrial boiler with biomass direct-fired, zoned, graded and split-phase combustion have essential differences from the aspects of fuel form and combustion mode, the straw bundle-fired boiler directly pushes bundled fuel into a hearth through a telescopic push rod, the fuel form is cuboid bundle-shaped fuel, the combustion mode is whole bundle combustion, and the combined grate environmental-friendly industrial boiler with biomass direct-fired, zoned, graded and split-phase combustion stably burns and reduces the fly ash rate. In the patent, the feeding device (4) comprises the shaftless screw feeder (28), so that the biomass fuel can enter the hearth from the feeding bin through the screw feeder, and the biomass fuel is crushed and scattered after passing through the screw feeder to present a bulk combustion state or a suspension combustion state different from a bundle combustion state, at the moment, the combustion is violent but difficult to control, and the fly ash in the boiler is serious.

The utility model with the publication number CN208587895U discloses a steam boiler with a waste heat boiler, which comprises a steam boiler body (1), a reciprocating grate (2) and a waste heat boiler (3); the method is characterized in that: the steam boiler body (1) is provided with a lower combustion chamber (1-1) and a dust removal chamber (1-2), and the lower combustion chamber (1-1) and the dust removal chamber (1-2) are distributed up and down and are communicated through a Venturi channel (1-3); the reciprocating grate (2) is arranged at the lower part in the lower combustion chamber (1-1); the dust removal device is characterized in that a dust remover (4) is arranged in the dust removal chamber (1-2), the dust remover (4) is located right above the Venturi channel (1-3), and a smoke inlet of the waste heat boiler (3) is connected with a smoke outlet of the dust removal chamber (1-2). The utility model discloses can improve dust collection efficiency and quality, and reduce the on-the-way calorific loss and improve waste heat recovery and utilization ratio.

Through analysis, a boiler related in a steam boiler with a waste heat boiler is a typical double-boiler-barrel horizontal reciprocating furnace water pipe boiler, coal is generally used as fuel in the boiler, the design of a feeding bin limits the entering of large-size fuel, a direct L-shaped hearth structure is not suitable for high-volatile low-calorific-value biomass fuel, high incomplete combustion loss is easily caused, and an air bin air supply system at the bottom of a furnace grate does not adopt segmented air supply, the biomass fuel has high ash content and light ash content, so that the air quantity supplied in the later combustion period is too large, the fly ash in the boiler is serious, a dust remover is blocked, and the normal operation of the boiler is influenced, so that the boiler is not suitable for straw bundling fuel.

The utility model with the bulletin number of CN206648019U discloses a biomass bundled fuel chain boiler, which comprises a furnace arch structure and a feeding structure, wherein the furnace arch structure comprises a front arch, a middle arch and a rear arch which are sequentially arranged above a chain grate, the middle arch consists of a vertical flame folding wall, the rear arch consists of an arch wall and a fire blocking wall which vertically extends upwards, the fire blocking wall is positioned between the front arch and the middle arch, the lower part of the fire blocking wall is connected with the front end of the arch wall, and the rear end of the arch wall is inclined downwards and extends to the position of the rear wall of a hearth to be connected with the rear end of the hearth; the space between the front arch and the rear arch is a first combustion chamber, the space between the rear arch and the middle arch is a second combustion chamber, and the space between the middle arch and the rear wall of the hearth is a third combustion chamber; the feeding structure comprises a feeding hole arranged on the front arch, one end of the feeding hole, which is positioned in the hearth, is provided with a wind shield which can be opened and closed, and a conveying channel is paved at the feeding hole. The utility model discloses a cooperation of furnace arch structure and feeding structure improves combustion temperature and combustion efficiency.

Through analysis, the biomass bundled fuel chain boiler adopts the chain grate, but the chain grate is not the best choice for the straw bundled fuel boiler, because the straw bundled fuel has larger size and is thicker, the straw bundled fuel is difficult to be burnt completely by a common combustion mode, and an ash shell generated after the outer layer of the fuel is combusted is attached to the surface of the fuel, so that the heat and mass transfer is prevented, the combustion is difficult to be carried out towards the inside, and the incomplete combustion is caused. And the chain grate and the fuel are in a relatively static state, so that the removal of an ash shell outside the fuel is not facilitated, the insufficient combustion is easily caused, and the ash is easily bridged and slagging to be attached to a grate to corrode equipment in static and high-temperature states. When the reciprocating grate moves, the fuel and the grate do relative movement in the horizontal direction and the vertical direction, at the moment, the fuel layer can be loosened, the surface ash shells are removed by mutual collision, the combustion is carried out inwards, the automatic fire pulling effect is good, and the movement among the grate segments is also beneficial to breaking larger ash blocks, so that the slagging corrosion of the grate is effectively reduced. Therefore, the reciprocating grate is more suitable for straw bundling fuel than a chain grate.

The utility model with the publication number of CN209415484U discloses a biomass reciprocating grate device, which comprises a driving motor, a main power shaft, a linkage plate, at least two layers of movable grates, at least two layers of static grates, a fixed support and a supporting seat, wherein the number of layers of the movable grates and the static grates is equal, the static grates and the movable grates are alternately arranged in a step shape in the vertical direction, the movable grates are arranged on the uppermost layer, and the static grates are arranged on the lowermost layer; the fixed support columns are vertically fixed on the supporting seat, and each static grate is fixedly connected with the fixed support columns through fixed connecting rods; each moving grate is fixedly connected with the linkage plate through a connecting rod, and the linkage plate is connected with the driving motor through a main power shaft. This reciprocal grate device of living beings is mainly to the direct combustion boiler that has reciprocal grate structure, integrates traditional many subregion reciprocal grates into integral type reciprocating mechanism to adopt interlock fixed knot structure between the adjacent grate segment of layer, guarantee boiler operation stable, safety.

Through analysis, the reciprocating structure fire grate in the biomass reciprocating fire grate device drives the linkage plate linkage shaft after the main power shaft is driven by the motor so as to drive the movable fire grate to move, and how to do reciprocating motion is not mentioned in the patent. The reciprocating grate used in the straw bundling boiler adopts a design that an eccentric wheel reciprocating mechanism drives a movable grate segment to do reciprocating motion through a connecting rod, the design difference is mainly that a linkage shaft between a movable grate segment and the connecting rod is connected in a transverse or vertical arrangement mode, when the grate has a large inclination angle or the movable grate segment is few, the transverse arrangement can ensure the synchronism of the movement of the grate, but when the grate has a small inclination angle or the movable grate segment is many, the steel consumption is large, the industrial production is not facilitated, and the linkage shaft arranged vertically has strong adaptability, simple and reliable design and less steel consumption.

Patent publication No. WO2019119385a1 provides a control method for an inclined multistage reciprocating forward-pushing garbage incinerator, comprising: distributing primary air quantity based on steam flow, steam drum pressure and drying section grate temperature; controlling the continuous movement of a feeding grate based on the material bed differential pressure of the incinerator; controlling the continuous movement of the incineration grate based on the heat value of the garbage and the steam flow, and controlling the movement of the incineration grate through steam drum pressure interlocking; controlling the air supply quantity at two sides based on the grate temperature; and controlling the distribution of secondary air quantity based on the boiler outlet oxygen quantity and CO (carbon monoxide).

Through analysis, the inclined multistage reciprocating forward-pushing boiler related to the control method for the inclined multistage reciprocating forward-pushing garbage incinerator is a large-scale industrial garbage incinerator, the fire grate of the inclined multistage reciprocating forward-pushing boiler comprises a sliding fire grate and a turning fire grate, the air volume and the movement speed of the fire grate are controlled in real time according to the combustion condition, and the overall technical level is very advanced. However, the equipment is designed only according to the waste incineration, and the combustion continuity, the calorific value and the like of the household waste are better than those of biomass fuels, and the ash content is low. The biomass straw bundling fuel has excessively high volatile content, high ash content and light weight and is easy to blow up, an L-shaped direct hearth in the equipment does not utilize full combustion and burnout of the volatile, and the fly ash rate of a reciprocating grate is originally higher than that of a common grate.

Disclosure of Invention

The invention provides a reciprocating grate straw bundle burning boiler for solving the defects in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

a reciprocating grate straw bundle burning boiler comprises an upper boiler body, a middle hearth and a lower grate, wherein the hearth is of a multi-arch structure and comprises a front arch, a middle arch and a rear arch, a secondary air supply system is arranged on the front arch, the middle arch is a fire wall which faces vertically downwards, the rear arch extends to the middle of the hearth from a rear wall of the hearth, a space between the front arch and the rear arch is a first combustion chamber, a space between the rear arch and the middle arch is a second combustion chamber, and a space between the middle arch and the rear wall of the hearth is a third combustion chamber;

the furnace grate is a reciprocating grate, a furnace door is arranged on the furnace hearth and corresponds to the feeding end of the reciprocating grate, and an auxiliary feeding mechanism is arranged outside the furnace door in a matched manner;

the grate is provided with a primary air supply system below, the primary air supply system comprises a plurality of air bins sequentially arranged along the advancing direction of the reciprocating grate, the air bins are connected with air supply pipelines, and each air bin is provided with an independent air adjusting device, so that a sectional type air supply mechanism is formed.

The reciprocating grate comprises a step-shaped structure formed by mutually overlapping grate segments, the grate segments are alternately arranged by movable grate segments and fixed grate segments, the movable grate segments are connected with an eccentric link mechanism through a movable grate beam, and the eccentric link mechanism drives the reciprocating grate to reciprocate.

The auxiliary feeding mechanism is a telescopic push rod, and the telescopic push rod points to the direction of the furnace door.

The independent air adjusting device comprises a wind shield arranged at the bottom of the wind cabin, the wind shield is horizontally and slidably inserted at the bottom of the wind cabin, and the wind shield moves to change the size of an air inlet of the corresponding wind cabin.

And a hearth flue gas outlet is formed in the top of the third combustion chamber, flue gas is discharged into a smoke exhaust pipe after heat exchange is carried out on the flue gas through a convection heating surface of the boiler body, and a dust removal device is arranged at the rear part of the smoke exhaust pipe.

The dust removal device is a two-stage dust removal device and comprises a cyclone dust collector and a bag type dust collector which are arranged in series along the smoke direction.

And the smoke exhaust pipe is also provided with a coal economizer.

And an ash removing opening is formed in the rear wall of the hearth of the third combustion chamber.

The conveying tail end of the reciprocating grate is correspondingly provided with a slag outlet.

The invention has the beneficial effects that:

1. the reciprocating grate is applied to the straw bundling fuel boiler, and the relative motion between the reciprocating grate and the fuel is favorable for removing the ash shell outside the fuel, so that the fire poking effect is good, the fuel can be continuously combusted inwards, and the fuel efficiency of the straw bundling fuel is improved. And because the motion of grate segment makes the ash bed appear not hard up, the ash content is difficult for taking over to form great ash cinder block, and easily breaks away, so can effectively reduce the ash content slagging rate, alleviate the corruption of ash content slagging to the grate.

The fire grate adopts an obliquely arranged reciprocating fire grate structure, fire grate pieces of the fire grate are mutually overlapped to form a ladder shape, movable fire grate pieces are connected with an eccentric wheel connecting rod mechanism into a whole through a movable fire grate beam, and the movable fire grate pieces are driven to do reciprocating motion through the eccentric wheel connecting rod mechanism. The fuel is pushed down from top to bottom in one stage, when the reciprocating grate moves, the fuel and the grate have relative movement in the horizontal direction and the vertical direction, at the moment, the fuel layer can be loosened, the surface ash shell is removed by mutual collision, the combustion is carried out inwards, and the automatic fire pulling effect is good.

2. The hearth of the invention adopts a multi-arch structure, and the application of the multi-arch structure can increase the residence time of the flue gas, so that volatile combustible substances can be fully combusted, and the heat transfer is enhanced.

The multi-arch structure of the invention is divided into a front arch, a middle arch and a rear arch, a hearth is divided into three combustion chambers, the front arch is in conventional arrangement and is used for suppressing fire, and a secondary air port is arranged to strengthen turbulent flow and enhance combustion. The middle arch is a vertical downward fire wall and is used for increasing a flue gas path, improving the residence time of flue gas and strengthening combustion and heat transfer. The rear arch extends from the rear wall of the hearth to the middle part of the hearth, and can guide high-temperature flue gas in the later combustion period to the front middle part of the hearth to enhance combustion, so that fuel not only can be subjected to radiation heat transfer of the front arch but also can be subjected to radiation action of the rear arch, the fuel can be well dried, and separation and combustion of volatile matters are accelerated. The space between the front arch and the rear arch is a first combustion chamber, the space between the rear arch and the middle arch is a second combustion chamber, and the space between the middle arch and the rear wall of the hearth is a third combustion chamber. The third combustion chamber is also used as a smoke dust settling chamber, and the rear wall of the hearth is provided with an ash cleaning port. When fuel is burnt in first combustion chamber, the air of once is blown in by the grate bottom, provides the overgrate air on encircleing before, is favorable to the abundant burning of volatile to the many archs structure has prolonged the dwell time of flue gas, makes the burning more abundant, and the heat transfer is more complete. The third combustion chamber is used as a burnout chamber and is also a smoke dust settling chamber, large-particle-size dust particles settle due to inertia and dead weight, and the settled dust is regularly drawn out from a dust cleaning opening on the rear wall of the hearth, so that large-particle-size ash settles in the third combustion chamber to avoid blocking a threaded smoke tube, and the smoke dust content in the smoke is effectively reduced.

3. The invention is provided with a primary air supply system under the fire grate, the primary air supply system comprises a plurality of air bins which are sequentially arranged along the advancing direction of the reciprocating fire grate, the air bins are connected with an air supply pipeline, each air bin is provided with an independent air adjusting device, so that a sectional type air supply mechanism is formed, the combustion is divided into a front stage, a middle stage and a rear stage which respectively correspond to the front part, the middle part and the rear part of the fire grate, the air quantity required in the early stage and the later stage of the combustion is smaller, so that the air ports of the air bins at the front end and the rear end of the fire grate can be adjusted to be smaller as required, and the air port is adjusted. The sectional type air supply mechanism has simple structure, can effectively improve the combustion efficiency and simultaneously reduces fly ash in a hearth.

4. The smoke exhaust pipe is provided with the two-stage dust removal device, and the cyclone dust removal and the cloth bag type dust removal are connected in series, so that the smoke content in the smoke can be effectively reduced, and the smoke exhaust pipe has the advantages of wide application range, high dust removal efficiency and no secondary pollution. Meanwhile, the smoke exhaust pipe is provided with a coal economizer for recycling waste heat in the smoke.

5. The biomass bundling fuel combustion device is suitable for combustion of biomass bundling fuel, is designed according to the combustion characteristics of the biomass bundling fuel, and effectively solves the problems of low mechanization degree, low heat efficiency, difficult thorough burning of the bundling fuel, serious furnace grate slagging, substandard smoke emission and the like of the original biomass boiler.

Drawings

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

FIG. 2 is a left side view of FIG. 1;

FIG. 3 is an enlarged schematic view of the reciprocating grate of FIG. 1;

FIG. 4 is a schematic structural view of a sectional type air supply mechanism according to the present invention;

FIG. 5 is a schematic sectional view taken along line A-A in FIG. 4;

FIG. 6 is a schematic view showing the structure of the two-stage dust removing apparatus of the present invention.

The reference numbers for the various components in the drawings are as follows: 1. a telescopic push rod; 2. a furnace door; 3. front arch; 4. primary air; 5. the front smoke box 6 is a boiler barrel; 7. a rear arch; 8. a middle arch; 9. a coal economizer; 10. cleaning the ash hole; 11. a hearth rear wall; 12. a motor; 13. a reciprocating grate; 14. an eccentric wheel link mechanism; 15. a movable fire grate segment; 16. a first combustion chamber; 17. a second combustion chamber; 18. a slag outlet; 19. a third combustion chamber; 20. a threaded smoke tube; 21. a convection heating surface; 22. a water cooled wall; 23. a down pipe; 24. collecting a box; 25. a wind bin; 26. fixing the fire grate segment; 27. a movable grate beam; 28. an air supply duct; 29. a wind deflector; 30. a smoke exhaust pipe; 31. a cyclone dust collector; 32. a bag filter; 33. a cyclone dust collector ash bucket; 34. a filter bag; 35. a flue gas outlet; 36. a bag type dust collector ash bucket; and 37, a flue gas inlet.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings.

As shown in figures 1 to 6, the straw bundle burning boiler with the reciprocating grate comprises a boiler body at the upper part, a hearth at the middle part and the grate at the lower part.

The boiler body mainly comprises a front smoke box 5, a boiler barrel 6, a threaded smoke pipe 20, a water-cooled wall 22, a down pipe 23, a header 24 and a convection heating surface 21, wherein the interior of the boiler is built by refractory materials, the exterior of the boiler is a steel frame framework and an outer wrapping panel, and the middle of the boiler is filled with heat insulation materials. The structure of the boiler body is the prior art, and the structure and the principle of each part are not detailed.

The hearth is of a multi-arch structure and comprises a front arch 3, a middle arch 8 and a rear arch 7, and the hearth is divided into three combustion chambers. The front arch 3 is arranged conventionally for suppressing fire and is provided with a secondary air port 4 (secondary air system) for strengthening turbulence and enhancing combustion. The middle arch 8 is a vertical downward fire wall and is used for increasing the path of flue gas, improving the residence time of the flue gas and strengthening combustion and heat transfer. The rear arch 7 extends to the middle of the hearth from the rear wall 11 of the hearth, and can guide the high-temperature flue gas in the later combustion period to the front middle of the hearth to strengthen combustion, so that the fuel is enabled to not only receive the radiation effect of the front arch in radiation heat transfer but also receive the radiation effect of the rear arch, the fuel can be well dried, and the separation and combustion of volatile matters are accelerated.

The space between the front arch 3 and the rear arch 7 is a first combustion chamber 16, the space between the rear arch 7 and the middle arch 8 is a second combustion chamber 17, and the space between the middle arch 8 and the rear wall 11 of the furnace is a third combustion chamber 19. The third combustion chamber 19 also serves as a smoke settling chamber, and the rear wall 11 of the hearth is provided with an ash cleaning port 10.

When fuel burns in first combustion chamber 16, the wind blows in by the grate bottom, provides the overgrate on the preceding arch 3, is favorable to the abundant burning of volatile to the residence time of flue gas has been prolonged to many arches structure, makes the burning more abundant, and the heat transfer is more complete. The third combustion chamber 19 is used as a burnout chamber and is also a smoke dust settling chamber, large-particle-size dust particles settle due to inertia and dead weight, and the settled dust is periodically drawn out from the ash cleaning port 10 on the rear wall 11 of the hearth, so that large-particle-size ash settles in the third combustion chamber 19 to avoid blocking the threaded smoke tube, and the smoke dust content in the smoke is effectively reduced.

The hearth of the invention adopts a multi-arch structure, and the application of the multi-arch structure can increase the residence time of the flue gas, so that volatile combustible substances can be fully combusted, and the heat transfer is enhanced.

The grate adopts the reciprocating grate 13 of slope arrangement, and the feed end of reciprocating grate 13 corresponds on the furnace is equipped with furnace gate 2, and the furnace gate 2 is outer to be arranged in the cooperation and is assisted feed mechanism, and the transport end of reciprocating grate 13 corresponds and is equipped with the slag notch. In this embodiment, the auxiliary feeding mechanism is a telescopic push rod 1, and the telescopic push rod 1 points to the direction of the oven door 2.

The reciprocating grate 13 comprises a ladder-shaped structure formed by mutually overlapping grate segments, the grate segments are alternately arranged by movable grate segments 15 and fixed grate segments 26, the movable grate segments 15 are connected with the eccentric link mechanism 14 through movable grate beams 27, the eccentric link mechanism 14 is driven by the speed regulating motor 12, and then the movable grate segments 15 are driven to reciprocate. The fuel is pushed down from top to bottom in one stage, when the reciprocating grate moves, the fuel and the grate have relative movement in the horizontal direction and the vertical direction, at the moment, the fuel layer can be loosened, the surface ash shell is removed by mutual collision, the combustion is carried out inwards, and the automatic fire pulling effect is good.

The reciprocating grate is applied to the straw bundling fuel boiler, and the relative motion between the reciprocating grate and the fuel is favorable for removing the ash shell outside the fuel, so that the fire poking effect is good, the fuel can be continuously combusted inwards, and the fuel efficiency of the straw bundling fuel is improved. And because the motion of grate segment makes the ash bed appear not hard up, the ash content is difficult for taking over to form great ash cinder block, and easily breaks away, so can effectively reduce the ash content slagging rate, alleviate the corruption of ash content slagging to the grate.

A primary air supply system is arranged below the reciprocating grate 13 and comprises a plurality of air bins 25 which are sequentially arranged along the advancing direction of the reciprocating grate 13, the air bins 25 are connected with an air supply pipeline 28, and each air bin 25 is provided with an independent air adjusting device, so that a sectional type air supply mechanism is formed.

The independent air adjusting device comprises an air baffle 29 arranged at the bottom of the air bin 25, the air baffle 29 is horizontally and slidably inserted at the bottom of the air bin, and the air baffle 29 moves to change the size of an air inlet of the corresponding air bin.

The primary air supply system adopts a sectional type air supply mechanism, the combustion is divided into a front stage, a middle stage and a rear stage which respectively correspond to the front part, the middle part and the rear part of the fire grate, and because the air quantity required in the early stage and the later stage of the combustion is small, the air ports of the air bins at the front end and the rear end of the fire grate can be adjusted to be small as required, and the air ports are increased in a middle vigorous combustion area. The sectional type air supply mechanism has simple structure, can effectively improve the combustion efficiency and simultaneously reduces fly ash in a hearth.

The top of the third combustion chamber is provided with a hearth smoke outlet, smoke passes through a convection heating surface 21 of a splayed flue part of the boiler body to reach a front smoke box 5 and then is discharged into a smoke exhaust pipe 30 after heat exchange through a screwed smoke pipe 20, and the smoke exhaust pipe 30 is provided with an economizer 9 for recovering waste heat in the smoke and then is connected with a dust removal device. In this embodiment, the two-stage dust removing device includes a cyclone 31 and a bag type dust remover 32 which are arranged in series along the direction of the flue gas.

The biomass straw has high ash content and light weight, and is very easy to be blown up by wind, so that the ash content in the flue gas is overhigh. In recent years, due to the national concern about environmental protection, especially the restriction of particulate matter in boiler pollutant emissions, the removal of soot has been an important consideration in the design of boilers. The common water bath dust remover has good dust removing effect, but is gradually eliminated due to secondary pollution. The design adopts the mode that the cyclone dust collector 31 and the bag type dust collector 32 are connected in series, two-stage dust collection is combined, and the dust collector has the advantages of wide application range, high dust collection efficiency and no secondary pollution. The cyclone dust collector 31 is used for primary dust collection, the bag-type dust collector 32 is arranged behind the cyclone dust collector for secondary dust collection due to no high temperature resistance, and two-stage dust collection is matched for use, so that the dust collection efficiency is improved.

The boiler dust-containing flue gas enters the cyclone type dust collector 31 along the flue gas inlet 37 under the guide of the induced draft fan, and rotates in the cyclone type dust collector, the dust particles are separated from the flue gas by virtue of centrifugal force and collected on the wall of the boiler, and the dust particles finally fall into the dust hopper 33 of the cyclone type dust collector under the action of gravity, so that the effect of removing the particles with large particle size is good. Then, the small-particle-size particulate matters enter the bag type dust collector 32 along with the flue gas, the smoke dust particles are filtered by the filter bag 34 and are blocked on the surface of the filter bag 34, and the clean gas penetrating through the filter bag is discharged from the flue gas outlet 35. Soot particles deposited on the surface of the filter bag 34 may fall out of the filter bag 34 by mechanical vibration and fall into the baghouse hopper 36.

The smoke exhaust pipe 30 is provided with the two-stage dust removal device, and the cyclone dust removal and the cloth bag type dust removal are connected in series, so that the smoke content in the smoke can be effectively reduced, and the smoke exhaust pipe has the advantages of wide application range, high dust removal efficiency and no secondary pollution. Meanwhile, the smoke exhaust pipe 30 is provided with an economizer 9 for recovering the waste heat in the smoke.

The primary air blower and the secondary air blower provided with the frequency converter supply air to the primary air system and the secondary air system, so that the air intake of the primary air and the secondary air is accurately controlled.

The biomass bundling fuel combustion device is suitable for combustion of biomass bundling fuel, is designed according to the combustion characteristics of the biomass bundling fuel, and effectively solves the problems of low mechanization degree, low heat efficiency, difficult thorough burning of the bundling fuel, serious furnace grate slagging, substandard smoke emission and the like of the original biomass boiler.

Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the scope of the present invention.

Claims

1. The utility model provides a reciprocal grate straw bundle burns boiler, includes the boiler body on upper portion, the furnace and the grate of lower part in middle part, its characterized in that: the hearth is of a multi-arch structure and comprises a front arch, a middle arch and a rear arch, a secondary air supply system is arranged on the front arch, the middle arch is a fire-blocking wall which is vertically downward, the rear arch extends to the middle of the hearth from the rear wall of the hearth, a space between the front arch and the rear arch is a first combustion chamber, a space between the rear arch and the middle arch is a second combustion chamber, and a space between the middle arch and the rear wall of the hearth is a third combustion chamber;

2. The reciprocating grate straw bale-burning boiler of claim 1, characterized in that: the reciprocating grate comprises a step-shaped structure formed by mutually overlapping grate segments, the grate segments are alternately arranged by movable grate segments and fixed grate segments, the movable grate segments are connected with an eccentric link mechanism through a movable grate beam, and the eccentric link mechanism drives the reciprocating grate to reciprocate.

3. The reciprocating grate straw bale-burning boiler of claim 1, characterized in that: the auxiliary feeding mechanism is a telescopic push rod, and the telescopic push rod points to the direction of the furnace door.

4. The reciprocating grate straw bale-burning boiler of claim 1, characterized in that: the independent air adjusting device comprises a wind shield arranged at the bottom of the wind cabin, the wind shield is horizontally and slidably inserted at the bottom of the wind cabin, and the wind shield moves to change the size of an air inlet of the corresponding wind cabin.

5. The reciprocating grate straw bale-burning boiler of any one of claims 1-4, characterized in that: and a hearth flue gas outlet is formed in the top of the third combustion chamber, flue gas is discharged into a smoke exhaust pipe after heat exchange is carried out on the flue gas through a convection heating surface of the boiler body, and a dust removal device is arranged at the rear part of the smoke exhaust pipe.

6. The reciprocating grate straw bale-burning boiler of claim 5, characterized in that: the dust removal device is a two-stage dust removal device and comprises a cyclone dust collector and a bag type dust collector which are arranged in series along the smoke direction.

7. The reciprocating grate straw bale-burning boiler of claim 5, characterized in that: and the smoke exhaust pipe is also provided with a coal economizer.

8. The reciprocating grate straw bale-burning boiler of any one of claims 1-4, characterized in that: and an ash removing opening is formed in the rear wall of the hearth of the third combustion chamber.

9. The reciprocating grate straw bale-burning boiler of any one of claims 1-4, characterized in that: the conveying tail end of the reciprocating grate is correspondingly provided with a slag outlet.