Utility model content
Structure of the present utility model is simple, reduces NOx generation amount in combustion process obvious.The combustion apparatus of the technical solution adopted in the utility model, comprises the first combustion chamber and the second combustion chamber, and described first chamber front end arranges charging aperture, it is characterized in that,
Described first combustion chamber and the second combustion chamber are the cylinder of horizontal placement;
The rear end of described first combustion chamber is connected with the second front end of burning by pipeline, and described pipeline and described first combustion chamber and the second combustion chamber are all tangentially;
Described first chamber front end is also provided with the first air inlet, and its end arranges the second air inlet, and the direction of described first air inlet and the second air inlet is the tangential of the first combustion chamber;
The front end of described pipeline or the second combustion chamber arranges the 3rd air inlet.
Plane perpendicular before described first combustion chamber charging aperture and the first combustion chamber, described first combustion chamber charging aperture is provided with eddy flow material-spraying device.
Described charging aperture is arranged at the sidewall of described first combustion chamber, and its direction is the tangential of described first combustion chamber.
Described 3rd air inlet is arranged at the second chamber front end sidewall, and the direction of described 3rd air inlet is the tangential of described second combustion chamber.
The beneficial effects of the utility model.
The ratio of the utility model by adopting stage burning mode to carry out conservative control fuel-air-temperature-time, reaches and improves flue dust and NO in fuel availability, reduction flue gas
xthe object of content, clean discharge.
Detailed description of the invention
The low NOx combustion problem of the living beings that the present invention relates to.The low NO of living beings
xcombustion technology system is exactly by fixed carbon after-flame, suppresses NO
xthe combustion system formed reaches the object of clean discharge.From combustion characteristics and the biomass clean combustion technology of biomass fuel, carry out arranging to the furnace air field, temperature field, excess air coefficient, heating surface distribution etc. of combustor comprehensively, reasonably.Biomass clean combustor all has strict considering to the selection of fuel, the temperature of combustion air, the oxygen-supplying amount in each stage flame district, combustion system.
(1) fuel is selected.Choose the microgranular biomass fuel of drying, pulverization process, require water content≤15%, particle diameter≤3mm, because powdered substance surface area ratio is large, moisture content is low, in anoxic atmosphere 300 DEG C--when 400 DEG C, fugitive constituent still can be separated out in a large number and burn; Can be controlled by classification method for supplying oxygen when employing half cracking, cyclone suspension mode are burnt and the furnace air field of layout combustor, temperature field, this is that the biomass fuel of other shapes cannot be accomplished.
(2) combustion air.Low NO
xthe combustion air temperature of swirl flow combustion machine need use normal temperature air.Although recovery boiler tail gas can improve in-furnace temperature as combustion air, save fuel, also likely increase NO
xdischarge, have data to show, in biomass combustion process, when the temperature of combustion air is preheating to 315 DEG C from 27 DEG C, NO
xdischarge capacity increases by 3 times.
(3) combustion system.Low NO
xswirl flow combustion machine adopts the combustion system of classification oxygen supply, stage burning, anoxic cracking, high temperature after-flame, is reached improve flue dust and NO in fuel availability, reduction flue gas by conservative control fuel-air-temperature-time
xthe object of content.
In living beings low NOx combusting technology system, burner is key link wherein.The low NO of living beings
xswirl flow combustion machine adopts Automated condtrol in a large number, feed and each level air-distribution of combustor all adopt frequency conversion control technique, the character of based on fuel and operating mode can adjust at any time, control feeding coal and oxygen-supplying amount, adjustment Ge Yan district temperature and the flame time of staying, thus suppress NO
xformation and the established NO that reduces
x.
The low NO of living beings
xthe precondition of burning is that fuel must carry out pretreatment, makes it adapt to the combustion requirements of burner.Low NO of the present invention
xcombustion technology system selects microparticle shape living beings as fuel, by after the physical method drying such as the tree root tip, stalk, sawdust, rice husk, peanut shell, Cassava stalk, pulverizing, screening as microparticle shaped fuel, make its particle diameter≤3mm, water content is reduced to less than 15%.Because the micronization processes of fuel makes its physical arrangement change greatly, combustion characteristics and pollutant emission characteristic improve significantly.Along with fuel particle particle diameter reduces, its surface area significantly increases, and can provide larger combustion reaction area, can solve fuel length drying time, insufficient, that boiler output is not enough, dust content is large problem of burning in the direct combustion process of living beings.But because the combustion system of biomass fuel (comprising compressed fuel) in common coal-burning boiler is grate firing---half cracking burning, need to carry out in high-temperature oxygen-enriched atmosphere, and in high-temperature oxygen-enriched atmosphere, the nitrogen in fuel is separated out rear rapid oxidation and is formed NO
x, go out in air to cause environmental pollution by fume emission, therefore suppress the formation of NOx to be the key link that biomass clean burns.
To combustion zone NO
xformation, secondly two most important influence factors are oxygen and temperature, and the time of the ratio of fuel and air, oxygen-enriched combusting is to NO
xformation also have a great impact, therefore the ratio of conservative control fuel-air-temperature-time is control NO
xthe key factor formed, obvious biomass fuel (comprising compressed fuel) is difficult to accomplish in ordinary combustion machine and plain cylindrical furnace.
Living beings low NOx combustion adopts stage burning mode to carry out the ratio of conservative control fuel-air-temperature-time by special-purpose assorted equipment, reaches and improves flue dust and NO in fuel availability, reduction flue gas
xthe object of content, clean discharge.
(1) first stage biomass fuel in burner stove tank with 250 DEG C--400 DEG C of low temperature pyrolyzers, burn in anoxic atmosphere.Fired state in this combustion zone carries out under fuel enrichment, oxygen-deficient operating mode, and because oxygen is not enough, flame temperature is lower, NCH and NH that the nitrogen of separating out in fuel generates
3react form NO Deng the oxygen be difficult to air
x, NO
xgenerate just less.
(2) second stage has entered the fugitive constituent of biomass fuel in burner stove tank last after-flame in first stage cracking burning and fixed carbon with 400 DEG C--and in 600 DEG C, temperature burns away in anoxic atmosphere, and flame reduces the NO generated in oxygen debt atmosphere
xfor N
2, suitably supplement air at second stage burning tip, the NOx decomposition combustion in high temperature, sufficient oxygen atmosphere making the fuel gas in flame, carbon granule and generated.
(3) phase III supplements excess air in boiler furnace, makes flame carry out phase III burning under high-temperature oxygen-enriched atmosphere, and in second stage burning, still unburnt carbon granule after-flame completes combustion process.Although still can NO be generated in this stage burning process
xbut, because flame compole when burner hearth combustion is short, restriction NO
xgenerate, its result is just the reduction of NO
xdischarge capacity.
Illustrate that detailed description of the invention of the present utility model is as follows below in conjunction with accompanying drawing.
As shown in Figure 1, biomass fuel enters the first combustion chamber 3 of horizontal layout from charging aperture 1, is powdered biomass combustor in this programme.Start to use igniter to light a fire in charging aperture source, after normal combustion, fuel enters in combustor and namely can burn, without the need to lighting a fire separately again.Adopt the mode of eddy flow to make combustion even, and the disturbance of eddy flow makes combustion instability, thus reduce the formation of NOx.For forming eddy flow, arrange the eddy flow material-spraying device 2 of structure as Fig. 2 at charging aperture place, its direction rotated as illustrated by the arrows in fig. 1.Optional scheme is that the direction of charging aperture is set to the tangential of the first combustion chamber in addition, and arranges injector at charging aperture place, and fuel, from charging aperture tangentially spraying into along the first combustion chamber, forms eddy flow.Eddy flow when this eddy flow direction and eddy flow material-spraying device 2 scheme is identical.
The charging aperture side of the first combustion chamber is provided with the first air inlet 4, and its direction is the tangential of the first combustion chamber, and identical with the direction of rotation of eddy flow material-spraying device 2.Blown by the first air inlet 4, carry out first time oxygen supply and form eddy flow in the first combustion chamber, oxygen-supplying amount is 80% of fuel combustion oxygen demand, fuel carries out first stage cracking and formation first flame district 9 of burning in richness material, anoxic atmosphere, and this first flame district temperature is at 250 DEG C--between 400 DEG C.Due to cold and oxygen deficient, the N separated out in fuel is converted into NO
xdegree extremely low.
The flame in this first flame district enters second stage burning under wind action in cyclone suspension mode in first time, forms the second flame district 8 in the first combustion chamber.Because the burning of the first flame district has exhausted a large amount of oxygen, the second flame district carries out imperfect combustion in degree of depth anoxic atmosphere, and temperature is at 400 DEG C--between 600 DEG C, form hypoxemia reducing zone, the NOx that reduction has generated.Carry out second time oxygen supply at the second air inlet 7 of the first burner ends, all the other 20% air that fuel combustion needs are inputted the second flame district end, under the effect of second time oxygen-supplying combustion-supporting, reach 800 DEG C-900 DEG C from the flame temperature of the first combustion chamber ejection.The direction of this second air inlet 7 arranges identical with the direction of the first air inlet 4, and the wind sprayed from this second air inlet, except oxygen supply, also continues the eddy flow in the first combustion chamber is continued.
Second flame district flame sprays into the second combustion chamber 10 from the first combustion chamber flame-throwing pipe 5 and carries out phase III burning, forms the 3rd flame district.Third time oxygen supply is carried out by the 3rd air inlet 10 being arranged on the second chamber front end sidewall, the excess air that fuel combustion needs is inputted in the second combustion chamber combustion-supporting, in the first combustion chamber, unburnt fixed carbon burns and complete after-flame in the second combustion chamber again, waste gas is discharged from flue gas leading 12, completes whole combustion process.3rd flame district temperature is at 900 DEG C--between 1000 DEG C, still can generate a small amount of NOx in combustion, the temperature in this flame district and NOx generation amount and excess air coefficient exponent function relation, excess air coefficient is low, then flame temperature raises, NOx generation amount is low, then flame temperature reduces excess air coefficient height, NOx generation amount is high, and excess air coefficient controls by third time air distribution.
Because the cracking of fuel is carried out substantially with burning in the first combustion chamber, the alkali metal in fuel and chlorine melt coking process all to be completed in the first combustion chamber, can not coking in the second combustion chamber.