CN212298949U - Decoupling combustion mechanical grate furnace - Google Patents
Decoupling combustion mechanical grate furnace Download PDFInfo
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- CN212298949U CN212298949U CN202020941487.4U CN202020941487U CN212298949U CN 212298949 U CN212298949 U CN 212298949U CN 202020941487 U CN202020941487 U CN 202020941487U CN 212298949 U CN212298949 U CN 212298949U
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Abstract
The utility model provides a decoupling combustion mechanical grate furnace, which comprises a pre-combustion device and a main furnace body, wherein the main furnace body comprises a main grate, a top arch, a rear wall and a furnace chamber, and the rear wall is provided with a rear arch extending towards the furnace chamber; a first lower partition wall and a second lower partition wall are sequentially arranged above the main grate along the movement direction; the lower partition wall is independently provided with an adjusting air pipe; the top arch is sequentially provided with a first upper partition wall and a second upper partition wall along the gas flowing direction, and the upper area of the lower partition wall is correspondingly divided into a gasification combustion area, a transition combustion area and a burnout area. The utility model discloses a divide into different combustion areas with the main furnace body, set up different partition walls and adjust the wind, improved the mixed effect of coal gas, flue gas and regulation wind in the furnace, make furnace shapeThe formed reductive combustion zone is more stable, the components are more easily controlled, the transition from the reductive atmosphere to the oxidative atmosphere is accurately controlled, and NO in a burnout zone is reducedxThe rebound of concentration improves the zoned combustion effect, and the combustion efficiency is higher.
Description
Technical Field
The utility model belongs to the technical field of combustion apparatus, a decoupling zero burning mechanical grate furnace is related to.
Background
The traditional coal-fired industrial boiler mainly adopts a layer combustion mode and is mostly a chain boiler, the problems of low combustion efficiency, high pollutant discharge amount and the like generally exist, and therefore, related emission reduction technologies need to be researched and developed to reduce NOxThe discharge amount of the coal-fired boiler is limited by the structure and the operation mode of the coal-fired boiler, such as a low-oxygen combustion technology, a flue gas recirculation combustion technology, an air separation and combustion technology and the like, so that the combustion equipment needs to be improved while the combustion technology is improved, and the advantages of the novel combustion technology are fully exerted.
The traditional mechanical fire grate furnace is a common coal-fired boiler, and adopts an ignition mode that a hearth radiates and heats the upper part of a fuel layer, the outlet area of a high-temperature and high-oxygen hearth must be close to a fuel ignition area, the fuel conveying direction on the fire grate is opposite to the flow direction of flue gas in the hearth in a main combustion area of the hearth, so that the reduction area at the initial stage of combustion cannot be effectively realized, the subarea or staged combustion at the later stage of combustion is an oxidation area, and the deep reduction of NO cannot be realizedxDischarging of (3); the recirculated flue gas of the mechanical grate furnace is mixed with air and introduced into the lower part of the grate so as to reduce NO by reducing the oxygen content in the airxBut this significantly reduces the ignition and burn-out rate of the fuel, thereby requiring a significant increase in grate length and furnace volume.
CN 101650025A discloses a decoupling combustion furnace and a decoupling combustion method, comprising a pyrolysis gasification chamber, and a semicoke combustion zone, a coke combustion zone and a burnout zone which are sequentially arranged below the pyrolysis gasification chamber, the decoupling combustion furnace further comprises a secondary combustion zone, at least one grate, a first air port and a second air port, wherein the grate pushes fuel to move to sequentially pass through the pyrolysis gasification chamber, the semicoke combustion zone, the coke combustion zone and the burnout zone, the lower part of the secondary combustion zone is in fluid communication with the upper part of the pyrolysis gasification chamber, the coke zone and the burnout zone to form a gas channel, the first air port is arranged in the gas channel, and the second air port is arranged in the secondary combustion zone and is used for supplementing air; although the device can solve the problem of slow pyrolysis speed to a large extent, the device shares one set of fire grate, and precombustion speed is slow, when the load improves, easily causes the precombustion area to burn and breaks off, is difficult to be applicable to large-scale combustion equipment.
CN 102563614A discloses a precombustion type mechanical grate decoupling combustion furnace and a combustion method thereof, comprising a furnace body, a main grate and a precombustion grate, wherein a combustion chamber partition wall is arranged in the furnace body and divides the internal space of the furnace body into an upstream precombustion chamber and a downstream main combustion chamber, the main grate is positioned at the lower part of the furnace body, the precombustion chamber is positioned above the front section of the main grate, the main combustion chamber is positioned above the rear section of the main grate, the precombustion chamber and the main combustion chamber are communicated through a flue gas channel above the partition wall and a coal bed channel below the partition wall, the precombustion grate is positioned in the precombustion chamber and is arranged above the main grate at a certain inclination angle so as to enable the coal bed to run onto the; the device mainly improves the combustion efficiency of fire coal by arranging the precombustion chamber and the precombustion grate, but the reduction zone and the oxidation zone of combustion are not clearly divided, so that the problem of poor combustion effect still exists.
In summary, for the decoupling combustion of mechanical grate furnace, the improvement of the device is needed to clarify the division and component control of the reduction zone and the oxidation zone, so as to improve the effect of staged combustion and reduce NOxAnd (4) discharging.
SUMMERY OF THE UTILITY MODEL
Problem to prior art existence, the utility model aims to provide a decoupling zero burning mechanical grate furnace, mechanical grate furnace through with the setting of firing device and main furnace body, especially the setting of different combustion zones and divider wall in the main furnace body, the diffusion mixed effect of flue gas, coal gas and regulation wind when can effectively improve the fuel burning, the transition of the stability of different combustion area territories and combustion atmosphere in the control furnace realizes the degree of depth staged combustion that mechanical grate fired the furnace.
To achieve the purpose, the utility model adopts the following technical proposal:
the utility model provides a decoupling combustion mechanical grate furnace, which comprises a pre-combustion device and a main furnace body, wherein the outlet of the pre-combustion device is connected with the inlet of the main furnace body; the main furnace body comprises a main fire grate, a top arch, a rear wall and a hearth surrounded by the main fire grate, the top arch and the rear wall, the pre-burning device is positioned above the front part of the main fire grate, the top arch is positioned above the main fire grate, the rear wall is positioned above the rear part of the main fire grate, a slag discharge port is arranged between the lower part of the rear wall and the rear part of the main fire grate, and a flue gas outlet is arranged between the upper part of the rear wall and the rear part of the top arch;
the rear wall is provided with a rear arch extending inwards the hearth, the rear part of the hearth is divided into an upper part and a lower part by the rear arch, and a slag discharge port and a flue gas outlet are separated; a first lower partition wall and a second lower partition wall are sequentially arranged above the main grate along the movement direction of the main grate, the area between the lower partition wall and the main grate is a fuel channel, and the area between the lower partition wall and the crown is a gas channel; the first lower partition wall and the second lower partition wall are independently provided with adjusting air pipes;
the crown arch is provided with a first upper partition wall and a second upper partition wall which extend to the hearth in sequence along the gas flowing direction, the upper region of the lower partition wall is correspondingly divided into a gasification combustion region, a transition combustion region and a burnout region, the transverse position of the first upper partition wall is positioned between the first lower partition wall and the second lower partition wall, and the transverse position of the second upper partition wall is positioned at the rear of the second lower partition wall.
The utility model discloses in, the structural design of mechanical grate furnace carries out the preliminary pyrolysis gasification of fuel with precombustion device earlier, make fuel can begin to burn at the grate front end, divide the gas region in the main furnace body into gasification combustion area again, a plurality of combustion areas of transition combustion area and burn-off area, the design of the different partition walls of rethread and regulation tuber pipe, the atmosphere of the different combustion areas of control is constituteed, improve coal gas, the flue gas reaches and mixes the effect with the diffusion of adjusting the wind, the main conversion stage of fuel nitrogen makes the reductive combustion area on a large scale that furnace formed more stable, and accurate control reductive atmosphere is to the transition of oxidizing atmosphere, reduce burn-off area NO, the gas that burns off areaxRebound of concentration so thatThe combustion effect of the subareas is more prominent.
Following conduct the utility model discloses preferred technical scheme, nevertheless do not conduct the utility model provides a technical scheme's restriction, through following technical scheme, can reach and realize better the utility model discloses a technical purpose and beneficial effect.
As the preferred technical scheme of the utility model, the anterior segment of crown arch is connected with the upper portion of precombustion device.
Preferably, the first lower partition wall is arranged above the front end of the main fire grate, and the first lower partition wall is provided with an adjusting gate plate.
Preferably, the distance from the bottom of the first lower partition wall to the main grate is greater than the distance from the second lower partition wall to the main grate.
The utility model discloses in, the semicoke fuel bed thickness on the main grate can effectively be adjusted in the setting of adjusting the flashboard on the first lower partition wall, when the air reaction that ensures fuel bed and lower part let in, gasify the burning under suitable condition, make it can produce CO in the burning of fuel bed lower part2And the upper part of the fuel layer is gasified to generate CO.
And the distance between the second lower partition wall and the main grate is controlled, so that the thickness of a semicoke material layer entering the rear grate can be adjusted, the semicoke can be completely burnt, and excessive air passes through the semicoke layer.
Preferably, the distance between the first lower partition wall and the second lower partition wall is 50-75% of the length of the main grate, such as 50%, 55%, 60%, 62%, 65%, 68%, 70%, 72%, 75%, etc., but not limited to the recited values, and other values not recited in the range of the values are also applicable.
As the utility model discloses preferred technical scheme, the upper portion of first lower partition wall is equipped with first regulation tuber pipe, first regulation tuber pipe is connected with at least one first regulation wind spray tube, for example one, two, three or four etc..
Preferably, a second adjusting air pipe is arranged at the upper part of the second lower partition wall, and the second adjusting air pipe is connected with at least one second adjusting air spray pipe, such as one, two, three or four second adjusting air spray pipes.
In the utility model, a first adjusting air pipe is arranged on the first lower partition wall, adjusting air can enter a gasification combustion area through the injection of the first adjusting air spray pipe, and the reducibility of the components is adjusted by adjusting the coal gas components in the reduction area and burning; the angle of the first adjusting air spray pipe can be changed, so that the mixing position and the component distribution of the adjusting air and the coal gas in the gasification combustion area are changed.
Similarly, the regulating air is sprayed into the transition combustion zone through the second regulating air spray pipe, the transition from the reducing atmosphere to the oxidizing atmosphere is regulated by regulating the oxygen supply and combustion, and the NO of the burnout zone is reducedxRebound of concentration; the angle of the second adjusting air spray pipe can be changed, so that the air flow mixing position and the component distribution of the adjusting air and the gasified coal gas flowing into the transition combustion zone from the gasification combustion zone are changed.
In a preferred embodiment of the present invention, the distance from the bottom of the first upper partition to the main grate is 1/3 to 2/3, for example, 1/3, 2/5, 1/2, 3/5, 2/3, which are the distances from the crown to the main grate.
Preferably, the distance from the bottom of the second upper partition wall to the main grate is 1/2-4/5 of the distance from the top arch to the main grate, such as 1/2, 3/5, 2/3, 7/10, 3/4 or 4/5, but the distance is not limited to the recited values, and other values not recited in the range of the values are also applicable.
The utility model discloses in, the partition wall is gone up to first upper baffle wall and second and is provided with the division that does benefit to the gas combustion region and gaseous mixture, and the distance of first upper baffle wall and grate is less than the distance of partition wall and grate on the second, can adapt to the big characteristics in big end to end of the flue gas volume of going out the cigarette behind the furnace to maintain the interior best velocity of flow and the pressure drop of flue gas.
As the preferred technical scheme of the utility model, the region that corresponds under the main grate between first lower partition wall and the second lower partition wall is equipped with gasification combustion area plenum.
Preferably, an air chamber of a burnout zone is arranged in an area below the main grate and corresponding to the rear part of the second lower partition wall.
In the utility model, the air chamber is arranged below the main grate, which can provide air for gasification combustion or burnout for the semicoke on the main grate, and the air quantity is adjusted according to the combustion conditions at different stages; the number of the air chambers can be multiple, so that the air inlet amount of different areas on the main grate can be adjusted according to the burning condition of the semicoke.
Preferably, the burnout zone is provided with a burnout air nozzle, and the burnout air nozzle is arranged at the lower part of the crown arch, the front end of the rear arch or the side wall of the hearth.
The utility model discloses in, for the abundant burning of fuel and flue gas in the burn-off district, can set up the overfire air spout in addition to the excess air in the maintenance burn-off district.
The utility model also provides a method of adopting above-mentioned mechanical grate furnace to carry out decoupling zero burning, the method includes following step:
(1) pre-burning the solid fuel, and pyrolyzing and gasifying the solid fuel to generate semicoke and pyrolysis and gasification coal gas;
(2) the semicoke generated in the step (1) enters the main grate and then moves along with the main grate to generate gasification combustion reaction; the pyrolysis gasification coal gas generated in the step (1) enters a gasification combustion zone, and is mixed with coal gas generated by semicoke gasification combustion to perform reductive combustion;
(3) the flue gas generated by the reductive combustion in the step (2) enters a transitional combustion zone and is mixed and combusted with coal gas generated at the rear part of a gasification combustion zone under the ventilation condition; after the semicoke passes through the second lower partition wall, fully burning the semicoke under the action of gas to obtain solid slag;
(4) and (4) fully burning the flue gas generated after the mixed combustion in the step (3) under the action of excess air, and then, leaving through a flue gas outlet.
As the preferable technical scheme of the utility model, the solid fuel in the step (1) comprises coal and/or biomass.
Preferably, the pre-combustion of step (1) is performed in a pre-combustion device.
Preferably, the pre-combustion device combusts in a downward ignition mode.
In the utility model, the fuel is pre-combusted, so that preliminary pyrolysis gasification can be realized, the fuel can start to combust at the front end of the fire grate, a preheating ignition section on the fire grate is eliminated, and the utilization rate of the fire grate is improved; the temperature at which the fuel is preliminarily combusted is 500 to 1000 ℃, for example, 500 ℃, 600 ℃, 700 ℃, 800 ℃, 900 ℃ or 1000 ℃, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.
As the preferable technical proposal of the utility model, step (2) the air is introduced from the gasification combustion area air chamber in the semi-coke gasification combustion process.
The utility model discloses in, the semicoke gasification burning on the grate under first partition wall and second between the partition wall, this stage fuel nitrogen content is higher, and the volume of letting in of control air makes it take place the oxygen-deficient burning, and the CO content of formation is more, keeps higher reducing atmosphere to reduce fuel nitrogen to NOxThe transformation of (3); and on the rear part of the fire grate, the nitrogen content of the fuel is less, and at the moment, excessive air needs to be introduced to accelerate the complete combustion of the semicoke.
The gasification combustion mode is adopted, so that the thickness of a fuel layer which can be processed can be increased, the space chamber combustion proportion is increased, the burn-out speed of later-stage fuel is improved, and the length of a fire grate and the volume of a hearth can be reduced; a thicker fuel layer is adopted in the reduction zone, more coal gas is generated, and the stability of the atmosphere of the reduction zone of the mechanical grate furnace zoned combustion can be improved; moreover, the fuel gasification combustion is adopted, so that the adaptability of the fuel is improved, the requirements on the fuel components and the size specification of irregular fuel are reduced, and the performance of combusting biomass and garbage can be improved; the biomass volatile content is high, the main pollutants of the garbage are also in the volatile content, and smoke is discharged from the rear part of the hearth, so that the retention time of the volatile content in the high-temperature hearth can be obviously prolonged, and the burnout of the volatile matter is facilitated.
Preferably, a mixed gas consisting of air and circulating flue gas is introduced into the gasification combustion zone in the step (2).
Preferably, the mixed gas is introduced through a first adjusting air pipe.
In the utility model, the mixed gas of combustion air and circulating flue gas is introduced from the adjusting air pipe, wherein the proportion of air and circulating flue gas can be adjusted, and the rigidity of adjusting air can be kept when the oxygen demand is less or oxygen supplementation is not needed by changing the proportion of air and flue gas of adjusting air, thereby realizing the disturbance and mixing effect of adjusting air on air flow; meanwhile, the reducing atmosphere in different areas can be more accurately adjusted by changing the incident angle of the adjusting wind; the uniformity of reducing atmosphere can be improved by mixing a proper amount of circulating flue gas with the adjusting air, so that local peroxide is avoided; the utility model discloses changed traditional flue gas recirculation using-way, not only can ensure the burn-out speed and the burn-out rate of fuel, also reduced flue gas recirculation volume and the energy consumption that increases from this.
The utility model discloses in, in the gas mixture that first regulation tuber pipe let in, combustion-supporting air accounts for getting into 0 ~ 10% of furnace total air volume, and circulating flue gas volume accounts for getting into 0 ~ 10% of furnace total air volume.
Preferably, NO is generated in the reductive combustion process in the step (2)xIs reduced to N2。
Preferably, the gasification combustion zone of step (2) has an excess air ratio of 0.6 to 0.95, such as 0.6, 0.65, 0.7, 0.75, 0.8, 0.9, or 0.95, but not limited to the recited values, and other values not recited in this range are equally applicable.
In the present invention, the combustion temperature of the gasification combustion zone is 700 to 1100 ℃, for example 700 ℃, 800 ℃, 900 ℃, 1000 ℃ or 1100 ℃, but not limited to the enumerated values, and other unrecited values in the numerical range are also applicable.
As the preferable technical proposal of the utility model, step (3) the mixed gas composed of air and circulating flue gas is introduced into the transitional combustion zone.
Preferably, the mixed gas is introduced through a second adjusting air pipe.
The utility model discloses in, the setting of tuber pipe is adjusted to the second, through the spouting of the gas mixture of combustion air and circulation flue gas, except the effect of above-mentioned both proportions, injection angle scheduling factor, still can accurate control reducing atmosphere here to the transition of oxidizing atmosphere, avoids gasification combustion area and the burnout to distinguish unobvious, influences the problem of combustion effect separately.
The utility model discloses in, in the gas mixture that the second governing tuber pipe let in, combustion-supporting air accounts for getting into 0 ~ 15% of furnace total air volume, and circulating flue gas volume accounts for getting into 0 ~ 15% of furnace total air volume.
Preferably, the excess air ratio in the transitional combustion zone of step (3) is 0.85 to 1.1, such as 0.85, 0.9, 0.95, 1.0, 1.05, or 1.1, but not limited to the recited values, and other unrecited values within the range are equally applicable.
The utility model discloses in, the combustion temperature in transition combustion area is 800 ~ 1200 ℃, for example 800 ℃, 900 ℃, 950 ℃, 1000 ℃, 1050 ℃, 1100 ℃, 1150 ℃ or 1200 ℃, but is not limited to the numerical value of enumerating, and other numerical values that do not enumerate are equally suitable in this numerical value range.
Preferably, the thickness of the semicoke after the second lower partition wall is passed through in step (3) is smaller than that of the semicoke in front of the second lower partition wall.
In the utility model, the material layer thickness can be different according to the difference of the front and back combustion reactions on the main fire grate, and the material layer thickness between the first lower partition wall and the second lower partition wall is required to be larger than the material layer thickness behind the second lower partition wall; overall, as the semicoke burns, the semicoke thickness generally decreases progressively along the direction of travel of the main grate.
Preferably, air is introduced from the air chamber of the burnout zone in the semi-coke burnout process in the step (3).
As the preferable technical proposal of the utility model, step (4) the air is introduced from the nozzle of the burnout zone.
Preferably, the air excess factor of the burnout zone in step (4) is 1.05 to 2, such as 1.05, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.8, or 2, but not limited to the recited values, and other values not recited in the range of values are equally applicable.
The utility model discloses in, the combustion temperature in burn-out area is 1000 ~ 1400 ℃, for example 1000 ℃, 1100 ℃, 1150 ℃, 1200 ℃, 1250 ℃, 1300 ℃, 1350 ℃ or 1400 ℃, but is not limited to the numerical value of enumerating, and other numerical values that do not enumerate are equally suitable in this numerical value range.
Compared with the prior art, the utility model discloses following beneficial effect has:
(1) the utility model uses the pre-burning device to carry out preliminary pyrolysis and gasification of the fuel, so that the fuel can start to burn at the front end of the fire grate, and the fuel flow direction of the main burning zone of the mechanical fire grate furnace is consistent with the smoke flow direction;
(2) through dividing different combustion zones in the main furnace body of mechanical grate furnace, set up different partition walls and regulation wind, improved in furnace coal gas, flue gas and with the diffusion mixed effect of regulation wind, make furnace formation's reductive combustion zone on a large scale more stable at fuel nitrogen main conversion stage, the control is changeed to the component, accurate control reductive atmosphere reduces burn-off district NO to the transition of oxidizing atmospherexThe rebound of concentration realizes the staged and zoned combustion of the fuel, and the combustion efficiency can reach more than 90 percent;
(3) the design of mechanical grate furnace has improved grate utilization ratio and combustion efficiency, has strengthened fuel adaptability, has reduced flue gas recirculation volume and energy consumption.
Drawings
Fig. 1 is a schematic structural diagram of a decoupling combustion mechanical grate furnace provided in embodiment 1 of the present invention;
the device comprises a pre-combustion device 1, a first lower partition wall 2, a first adjusting air pipe 3, a first adjusting air spray pipe 4, a main fire grate 5, a crown 6, a gasification combustion zone air chamber 7, a gasification combustion zone 8, a first upper partition wall 9, a second lower partition wall 10, a second adjusting air pipe 11, a second adjusting air spray pipe 12, a transition combustion zone 13, a second upper partition wall 14, a burnout zone air chamber 15, a rear arch 16, a burnout zone 17, a flue gas outlet 18, a slag discharge port 19 and a rear wall 20.
Detailed Description
To better explain the utility model, the technical proposal of the utility model is convenient to understand, and the utility model is further explained in detail below. However, the following embodiments are only simple examples of the present invention, and do not represent or limit the scope of the present invention, which is defined by the appended claims.
The following are typical but non-limiting examples of the present invention:
example 1:
the embodiment provides a decoupling combustion mechanical grate furnace, the structural schematic diagram of the mechanical grate furnace is shown in fig. 1, and the mechanical grate furnace comprises a pre-combustion device 1 and a main furnace body, wherein an outlet of the pre-combustion device 1 is connected with an inlet of the main furnace body; the main furnace body comprises a main furnace grate 5, a top arch 6, a rear wall 20 and a hearth surrounded by the main furnace grate 5, the top arch 6 and the rear wall 20, the pre-combustion device 1 is positioned above the front part of the main furnace grate 5, the top arch 6 is positioned above the main furnace grate 5, the front section of the top arch 6 is connected with the upper part of the pre-combustion device 1, the rear wall 20 is positioned above the rear part of the main furnace grate 5, a slag discharge port 19 is arranged between the lower part of the rear wall 20 and the rear part of the main furnace grate 5, and a flue gas outlet 18 is arranged between the upper part of the rear wall 20 and the rear part of the top arch 6;
the rear wall 20 is provided with a rear arch 16 extending inwards the hearth, the rear part of the hearth is divided into an upper part and a lower part by the rear arch 16, and a slag discharge port 19 is separated from a flue gas outlet 18; a first lower partition wall 2 and a second lower partition wall 10 are sequentially arranged above the main grate 5 along the movement direction of the main grate 5, the area between the lower partition wall and the main grate 5 is a fuel channel, and the area between the lower partition wall and the crown 6 is a gas channel; the first lower partition wall 2 and the second lower partition wall 10 are independently provided with adjusting air pipes;
the crown arch 6 is sequentially provided with a first upper partition wall 9 and a second upper partition wall 14 which extend towards the hearth along the gas flowing direction, the upper area of the lower partition wall is correspondingly divided into a gasification combustion area 8, a transition combustion area 13 and a burnout area 17, the transverse position of the first upper partition wall 9 is positioned between the first lower partition wall 2 and the second lower partition wall 10, and the transverse position of the second upper partition wall 14 is positioned behind the second lower partition wall 10.
The first lower partition wall 2 is arranged above the front end of the main fire grate 5, and an adjusting flashboard is arranged on the first lower partition wall 2; the distance from the bottom of the first lower partition wall 2 to the main grate 5 is greater than the distance from the second lower partition wall 10 to the main grate 5; the distance between the first lower partition wall 2 and the second lower partition wall 10 is 70% of the length of the main grate 5.
A first adjusting air pipe 3 is arranged at the upper part of the first lower partition wall 2, and the first adjusting air pipe 3 is connected with three first adjusting air spray pipes 4; and a second adjusting air pipe 11 is arranged at the upper part of the second lower partition wall 10, and the second adjusting air pipe 11 is connected with three second adjusting air spray pipes 12.
The distance from the bottom of the first upper partition wall 9 to the main grate 5 is 1/3 of the distance from the crown 6 to the main grate 5, and the distance from the bottom of the second upper partition wall 14 to the main grate 5 is 1/2 of the distance from the crown 6 to the main grate 5.
An air chamber 7 of a gasification combustion area is arranged in the area below the main grate 5 and corresponding to the space between the first lower partition wall 2 and the second lower partition wall 10; an air chamber 15 of a burnout zone is arranged in an area below the main grate 5 and corresponding to the rear part of the second lower partition wall 10.
The burnout zone 17 is provided with a burnout air nozzle which is arranged at the front end of the rear arch 16.
Example 2:
the embodiment provides a decoupling combustion mechanical grate furnace, which comprises a pre-combustion device 1 and a main furnace body, wherein an outlet of the pre-combustion device 1 is connected with an inlet of the main furnace body; the main furnace body comprises a main furnace grate 5, a top arch 6, a rear wall 20 and a hearth surrounded by the main furnace grate 5, the top arch 6 and the rear wall 20, the pre-combustion device 1 is positioned above the front part of the main furnace grate 5, the top arch 6 is positioned above the main furnace grate 5, the front section of the top arch 6 is connected with the upper part of the pre-combustion device 1, the rear wall 20 is positioned above the rear part of the main furnace grate 5, a slag discharge port 19 is arranged between the lower part of the rear wall 20 and the rear part of the main furnace grate 5, and a flue gas outlet 18 is arranged between the upper part of the rear wall 20 and the rear part of the top arch 6;
the rear wall 20 is provided with a rear arch 16 extending inwards the hearth, the rear part of the hearth is divided into an upper part and a lower part by the rear arch 16, and a slag discharge port 19 is separated from a flue gas outlet 18; a first lower partition wall 2 and a second lower partition wall 10 are sequentially arranged above the main grate 5 along the movement direction of the main grate 5, the area between the lower partition wall and the main grate 5 is a fuel channel, and the area between the lower partition wall and the crown 6 is a gas channel; the first lower partition wall 2 and the second lower partition wall 10 are independently provided with adjusting air pipes;
the crown arch 6 is sequentially provided with a first upper partition wall 9 and a second upper partition wall 14 which extend towards the hearth along the gas flowing direction, the upper area of the lower partition wall is correspondingly divided into a gasification combustion area 8, a transition combustion area 13 and a burnout area 17, the transverse position of the first upper partition wall 9 is positioned between the first lower partition wall 2 and the second lower partition wall 10, and the transverse position of the second upper partition wall 14 is positioned behind the second lower partition wall 10.
The first lower partition wall 2 is arranged above the front end of the main fire grate 5, and an adjusting flashboard is arranged on the first lower partition wall 2; the distance from the bottom of the first lower partition wall 2 to the main grate 5 is greater than the distance from the second lower partition wall 10 to the main grate 5; the distance between the first lower partition wall 2 and the second lower partition wall 10 is 50% of the length of the main grate 5.
A first adjusting air pipe 3 is arranged at the upper part of the first lower partition wall 2, and the first adjusting air pipe 3 is connected with a first adjusting air spray pipe 4; and a second adjusting air pipe 11 is arranged at the upper part of the second lower partition wall 10, and the second adjusting air pipe 11 is connected with two second adjusting air spray pipes 12.
The distance from the bottom of the first upper partition wall 9 to the main grate 5 is 2/3 of the distance from the crown 6 to the main grate 5, and the distance from the bottom of the second upper partition wall 14 to the main grate 5 is 4/5 of the distance from the crown 6 to the main grate 5.
An air chamber 7 of a gasification combustion area is arranged in the area below the main grate 5 and corresponding to the space between the first lower partition wall 2 and the second lower partition wall 10; an air chamber 15 of a burnout zone is arranged in an area below the main grate 5 and corresponding to the rear part of the second lower partition wall 10.
The burnout zone 17 is provided with a burnout air nozzle which is arranged at the lower part of the crown 6.
Example 3:
the present embodiment provides a combustion method of a decoupled-combustion mechanical grate furnace, which is performed in the mechanical grate furnace of embodiment 1, and includes the following steps:
(1) the biomass fuel enters the pre-burning device 1 for pre-burning, the pre-burning temperature is 600 ℃, and the pyrolysis gasification generates semi-coke and pyrolysis gasification coal gas;
(2) the semicoke generated in the step (1) enters the main grate 5 and then moves along with the main grate 5 to generate gasification combustion reaction, and air is introduced from an air chamber 7 of a gasification combustion area in the gasification combustion process of the semicoke; the pyrolysis gasification coal gas generated in the step (1) enters a gasification combustion zone 8, and is mixed with coal gas generated by semicoke gasification combustion for reductive combustion, the combustion temperature is 900 ℃, mixed gas consisting of air and circulating flue gas is introduced into the gasification combustion zone 8, the excess air coefficient is 0.8, and NO in the reductive combustion processxIs reduced to N2；
(3) The flue gas generated by the reductive combustion in the step (2) enters a transition combustion zone 13, and is mixed and combusted with the coal gas generated at the rear part of the gasification combustion zone 8 under the ventilation condition, the combustion temperature is 1000 ℃, the transition combustion zone 13 is introduced with mixed gas consisting of air and circulating flue gas, and the excess air coefficient is 1.0; after the semicoke passes through the second lower partition wall 10, fully burning the semicoke under the action of air introduced into an air chamber 15 of a burnout area to obtain solid slag, and discharging the solid slag from a slag discharge port 19;
(4) and (4) fully burning the flue gas generated after the mixed combustion in the step (3) under the action of excess air introduced from a nozzle of a burnout zone, wherein the burnout temperature is 1200 ℃, and the excess air coefficient is 1.5, and then, the flue gas leaves through a flue gas outlet 18.
In the embodiment, the mechanical grate furnace is adopted for decoupling combustion of the biomass fuel, the combustion efficiency can reach 92%, and NO in flue gasxThe content meets the emission requirement, and no additional treatment is needed.
Example 4:
the present embodiment provides a combustion method of a decoupled-combustion mechanical grate furnace, which is performed in the mechanical grate furnace of embodiment 1, and includes the following steps:
(1) the pulverized coal fuel enters the pre-combustion device 1 for pre-combustion, the pre-combustion temperature is 800 ℃, and the pulverized coal fuel is pyrolyzed and gasified to generate semi-coke and pyrolyzed and gasified coal gas;
(2) the semicoke generated in the step (1) enters the main grate 5 and then moves along with the main grate 5 to generate gasification combustion reaction, and air is introduced from an air chamber 7 of a gasification combustion area in the gasification combustion process of the semicoke; the pyrolysis gasification coal gas generated in the step (1) enters gasThe gasification combustion zone 8 is mixed with coal gas generated by semicoke gasification combustion and then subjected to reductive combustion, the combustion temperature is 1100 ℃, mixed gas consisting of air and circulating flue gas is introduced into the gasification combustion zone 8, the excess air coefficient is 0.6, and NO is generated in the reductive combustion processxIs reduced to N2；
(3) The flue gas generated by the reductive combustion in the step (2) enters a transition combustion zone 13, and is mixed and combusted with the coal gas generated at the rear part of the gasification combustion zone 8 under the ventilation condition, the combustion temperature is 1200 ℃, the transition combustion zone 13 is introduced with mixed gas consisting of air and circulating flue gas, and the excess air coefficient is 0.85; after the semicoke passes through the second lower partition wall 10, fully burning the semicoke under the action of air introduced into an air chamber 15 of a burnout area to obtain solid slag, and discharging the solid slag from a slag discharge port 19;
(4) and (4) fully burning the flue gas generated after the mixed combustion in the step (3) under the action of excess air introduced from a nozzle of a burnout zone, wherein the burnout temperature is 1400 ℃, and the excess air coefficient is 1.5, and then, the flue gas leaves through a flue gas outlet 18.
In the embodiment, the mechanical grate furnace is adopted for decoupling combustion of pulverized coal fuel, the combustion efficiency can reach 94%, and NO in flue gasxThe content meets the emission requirement, and no additional treatment is needed.
Example 5:
the present embodiment provides a combustion method of a decoupled-combustion mechanical grate furnace, which is performed in the mechanical grate furnace of embodiment 2, and includes the following steps:
(1) the biomass fuel enters the pre-burning device 1 for pre-burning, the pre-burning temperature is 500 ℃, and the pyrolysis and gasification are carried out to generate semi-coke and pyrolysis and gasification coal gas;
(2) the semicoke generated in the step (1) enters the main grate 5 and then moves along with the main grate 5 to generate gasification combustion reaction, and air is introduced from an air chamber 7 of a gasification combustion area in the gasification combustion process of the semicoke; the pyrolysis gasification coal gas generated in the step (1) enters a gasification combustion zone 8, and is mixed with coal gas generated by semicoke gasification combustion to perform reductive combustion, the combustion temperature is 800 ℃, mixed gas consisting of air and circulating flue gas is introduced into the gasification combustion zone 8, the excess air coefficient is 0.9, and the reductive combustion is performedIn-process NOxIs reduced to N2；
(3) The flue gas generated by the reductive combustion in the step (2) enters a transition combustion zone 13, and is mixed and combusted with the coal gas generated at the rear part of the gasification combustion zone 8 under the ventilation condition, the combustion temperature is 850 ℃, the transition combustion zone 13 is introduced with mixed gas consisting of air and circulating flue gas, and the excess air coefficient is 1.05; after the semicoke passes through the second lower partition wall 10, fully burning the semicoke under the action of air introduced into an air chamber 15 of a burnout area to obtain solid slag, and discharging the solid slag from a slag discharge port 19;
(4) and (4) fully burning the flue gas generated after the mixed combustion in the step (3) under the action of excess air introduced from a nozzle of a burnout zone, wherein the burnout temperature is 1100 ℃, and the excess air coefficient is 1.2, and then, the flue gas leaves through a flue gas outlet 18.
In the embodiment, the mechanical grate furnace is adopted for decoupling combustion of the biomass fuel, the combustion efficiency can reach 91%, and NO in flue gasxThe content meets the emission requirement, and no additional treatment is needed.
Comparative example 1:
this comparative example provides a decoupled combustion mechanical grate furnace whose structure is as in example 1, the only difference being: a second lower partition wall 10 and an adjusting air pipe thereof are not arranged above the main grate, a second upper partition wall 14 is not arranged on the crown 6, and a transitional combustion area 13 is not included in the division of the area above the lower partition wall.
In the comparative example, the mechanical grate furnace is not provided with the transition combustion zone, so that the transition from the reducing atmosphere to the oxidizing atmosphere in the gas-phase combustion zone is difficult to ensure, the stability of the reducing atmosphere in the reducing combustion zone is poor, and NO is generatedxLow reduction efficiency and NO in oxygen-rich condition in the burnout zonexThe concentration is easy to rebound, NO in the smoke gasxThe content is relatively high, and the emission can not reach the standard.
It can be seen from the above embodiments and comparative examples that the mechanical grate furnace of the present invention uses the pre-combustion device to perform the preliminary pyrolysis gasification of the fuel, so that the fuel can start to burn at the front end of the grate; different combustion areas are divided in the main furnace body, different partition walls and adjusting air are arranged,the diffusion mixing effect of the coal gas, the flue gas and the adjusting air in the hearth is improved, a large-range reductive combustion zone formed by the hearth is more stable in the main fuel nitrogen conversion stage, the components are easier to control, the transition from the reductive atmosphere to the oxidative atmosphere is accurately controlled, and NO in a burnout zone is reducedxThe rebound of concentration realizes the staged and zoned combustion of the fuel, and the combustion efficiency can reach more than 90 percent; the design of the mechanical grate furnace improves the utilization rate and the combustion efficiency of the grate, enhances the fuel adaptability and reduces the smoke gas recirculation quantity and the energy consumption.
The applicant states that the present invention is described in the above embodiments, but the present invention is not limited to the above detailed device, i.e. the present invention must not be implemented by relying on the above detailed device. It should be clear to those skilled in the art that any improvement of the present invention, to the addition of the equivalent replacement and auxiliary devices of the present invention, the selection of the specific mode, etc., all fall within the scope of protection and disclosure of the present invention.
Claims (10)
1. A decoupling combustion mechanical grate furnace is characterized in that the mechanical grate furnace comprises a pre-combustion device and a main furnace body, wherein an outlet of the pre-combustion device is connected with an inlet of the main furnace body; the main furnace body comprises a main furnace grate, a top arch, a rear wall and a hearth surrounded by the main furnace grate, the top arch and the rear wall, the pre-combustion device is positioned above the front part of the main furnace grate, the top arch is positioned above the main furnace grate, the front section of the top arch is connected with the upper part of the pre-combustion device, the rear wall is positioned above the rear part of the main furnace grate, a slag discharge port is arranged between the lower part of the rear wall and the rear part of the main furnace grate, and a flue gas outlet is arranged between the upper part of the rear wall and the rear part of the top arch;
the rear wall is provided with a rear arch extending inwards the hearth, the rear part of the hearth is divided into an upper part and a lower part by the rear arch, and a slag discharge port and a flue gas outlet are separated; a first lower partition wall and a second lower partition wall are sequentially arranged above the main grate along the movement direction of the main grate, the area between the lower partition wall and the main grate is a fuel channel, and the area between the lower partition wall and the crown is a gas channel; the first lower partition wall and the second lower partition wall are independently provided with adjusting air pipes;
the crown arch is provided with a first upper partition wall and a second upper partition wall which extend to the hearth in sequence along the gas flowing direction, the upper region of the lower partition wall is correspondingly divided into a gasification combustion region, a transition combustion region and a burnout region, the transverse position of the first upper partition wall is positioned between the first lower partition wall and the second lower partition wall, and the transverse position of the second upper partition wall is positioned at the rear of the second lower partition wall.
2. The decoupled combustion mechanical grate furnace of claim 1 wherein the first lower partition is disposed above a front end of the main grate, the first lower partition having an adjustable gate.
3. The decoupled combustion mechanical grate furnace of claim 1, wherein the distance from the bottom of the first lower partition to the main grate is greater than the distance from the second lower partition to the main grate.
4. The decoupled combustion mechanical grate furnace of claim 1, wherein the distance between the first lower partition wall and the second lower partition wall is 50-75% of the length of the main grate.
5. The mechanical grate furnace with decoupled combustion of claim 1, wherein a first adjusting air duct is provided at an upper portion of the first lower partition wall, and at least one first adjusting air nozzle is connected to the first adjusting air duct.
6. The mechanical grate furnace with decoupled combustion of claim 1, wherein a second adjusting air duct is provided at an upper portion of the second lower partition wall, and at least one second adjusting air nozzle is connected to the second adjusting air duct.
7. The decoupled combustion mechanical grate furnace of claim 1, wherein the distance from the bottom of the first upper partition wall to the main grate is 1/3-2/3 of the distance from the crown to the main grate;
the distance between the bottom of the second upper partition wall and the main grate is 1/2-4/5 of the distance between the crown and the main grate.
8. The decoupled combustion mechanical grate furnace of claim 1 wherein a gasification combustion zone plenum is provided below the primary grate in an area between the first lower partition and the second lower partition.
9. The decoupled combustion mechanical grate furnace of claim 1 wherein a burn-out zone plenum is provided below the primary grate in an area behind the second lower partition wall.
10. The decoupled combustion mechanical grate furnace of claim 1, wherein the burnout zone is provided with over-fire air jets disposed on a lower portion of the crown arch, a front end of the rear arch, or a side wall of the furnace.
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