CN100431670C - Energy-saving method for denitrogenation of horizontal chained coal fired boiler - Google Patents

Abstract

The present invention discloses a denitrification and energy-saving method for horizontal chain coal-fired boilers. The method comprises: 1. partial flue gas discharged in a flue gas exhaust pipeline of a boiler is led in a blower of the boiler, the oxygen content in the blower of the boiler is controlled by adjusting the proportion of the led flue gas and fresh air in the blower of the boiler, the combustion speed of coal is controlled, and thereby, the temperature of a main boiler chamber of the boiler is controlled; 2. fresh air is led in areas with temperature not below 700 DEG C at the crossed interface of the main boiler chamber of the boiler and a heat exchange chamber or in a flue gas passage in the heat exchange chamber, and combustible gas in the boiler atmosphere can be combusted sufficiently by oxygen in the fresh air. The discharge total amount of flue gas and the content of NO in flue gas are effectively lowered by the method of the present invention, residual heat in partial flue gas is utilized, and the environmental protection discharge of industrial boilers is realized.

Description

The energy-saving method for denitrogenation of horizontal chained coal fired boiler

Technical field

The present invention relates to the coal-burning boiler field, particularly relate to the denitrogenation power-saving technology of horizontal chained coal fired boiler.

Background technology

Coal-burning boiler can contain NO in the product of burning in combustion process_xEtc. harmful substance, if will have NO_xBurnt gas directly be discharged in the air, can produce bigger harm to natural environment.At present, for NO_xControl technology be mainly the NO that removes in the flue gas_x, when adopting this traditional denitrogenation method, device structure complexity, equipment investment are big, in the process of denitrogenating, also need add other auxiliary substance in flue gas, and it is bigger to denitrogenate cost.For small scall coal-fired boiler, adopt traditional denitrogenation method then to be difficult to more realize.

Summary of the invention

At the deficiencies in the prior art, purpose of the present invention be exactly to provide a kind of invest little, boiler plant itself simply transformed the energy-saving method for denitrogenation that just can realize low emission and energy-conservation suitable horizontal chained coal fired boiler.

For achieving the above object, the energy-saving method for denitrogenation of a kind of horizontal chained coal fired boiler of the present invention is specially:

1) partial fume that is discharged in the boiler exhaust gas pipeline is introduced in the boiler blower, by adjust in the boiler blower the ratio of the flue gas of introducing and fresh air control oxygen content in the air blast, with coal-fired burning velocity in the control boiler, thereby realize to temperature controlling in the boiler main furnace chamber with to NO_xThe inhibition that generates;

2) in being not less than 700 ℃ zone, the temperature at the interface or in the exhaust gases passes in the Heat Room that boiler main furnace chamber and Heat Room intersect introduces new wind, the boiler atmosphere that new wind and main furnace chamber are discharged is mixed, and utilizes the oxygen in the new wind that the fuel gas in the described boiler atmosphere is fully burnt.

Further, the described mode that flue gas is introduced in the boiler blower is idle introducing, the flue gas outlet is arranged on delivery outlet one side of boiler exhaust gas pipeline air-introduced machine, and the malleation of being drawn in the flue gas utilization smoke discharging pipe enters in the bleed pipeline that links to each other with boiler blower automatically.

Further, the oxygen in the described new wind also makes the part NO in the described boiler atmosphere further react generation NO₂

Further, described fuel gas comprises CO and C_mH_n

Further, the mode of the new wind of described introducing is idle introducing, and the negative pressure that at the interface or in the Heat Room inner gas passage temperature of new wind by described main furnace chamber and described Heat Room is not less than in 700 ℃ the zone is sucked automatically.

Further, the new wind of described idle introducing is realized by hermetic sealing substrate is set, described hermetic sealing substrate is arranged on the gas channel of the main furnace chamber of described boiler and Heat Room intersection, hermetic sealing substrate links to each other with the inwall of Heat Room is airtight with the inwall of main furnace chamber, and hermetic sealing substrate is provided with the through hole of some perforation main furnace chambers and Heat Room; One bleed pipeline is used for from the external world gas in main furnace chamber and introduces new wind, and the air outlet of described bleed pipeline is arranged in the main furnace chamber, and the new wind of introducing passes through hole and enters in the Heat Room with after the boiler atmosphere in the main furnace chamber is mixed.

Further, the resh air requirement of introducing by the control valve control of regulating described bleed pipeline.

Further, by regulating the number of openings on the described hermetic sealing substrate or the area of section of through hole, the flow velocity of adjusting boiler atmosphere in the main furnace chamber to be changing the negative pressure degree in the Heat Room, thereby changes the resh air requirement of introducing.

After boiler blower is introduced the ducted flue gas of boiler exhaust gas, reduced the whole oxygen content that blasts in the boiler gas, control reaction speed coal-fired in the boiler, and then reduced boiler main furnace chamber temperature, thereby reduced NO_xGrowing amount; After new wind is introduced in ad-hoc location or zone in boiler, fuel gas in the boiler atmosphere is fully burned, neither causes boiler main furnace chamber temperature to raise, fuel is fully used, make the part NO in the boiler atmosphere continue reaction with the oxygen in the stylish wind, generate NO₂, NO₂Generation make NO in the flue gas again_xFurther absorbed at the flue gas desulfurization treatment fluid, therefore, adopted the inventive method, can be reduced the total emission volumn of boiler smoke and the NO in the flue gas effectively_xContent, and make waste heat in the partial fume obtain utilizing, realized the environment protection emission of Industrial Boiler.

Description of drawings

The vertical view of Fig. 1 horizontal chained coal fired boiler of unpowered bleed device for the present invention is equipped with;

Fig. 2 is the A-A view of Fig. 1.

The specific embodiment

Horizontal chained coal fired boiler is to utilize chain that coal cinder is sent in the burner hearth, below chain, utilize air blast to provide coal combustion required air from the export-oriented main furnace chamber of stove, join with main furnace chamber and to be Heat Room, be provided with flue and the water pipe on flue in the Heat Room, the high-temperature flue gas of main furnace chamber output, by flue with the water in the heat transferred water pipe.Main furnace chamber can dwindle suddenly gradually towards the area of section of outlet one side of Heat Room, and the outlet flare of main furnace chamber with the cross section that the smoke evacuation of dwindling main furnace chamber exports, is accelerated the flow velocity that high-temperature flue gas enters flue in the heating clamber thereby play.The boiler heating clamber is provided with exhaust opening, and the outlet and the exhaust opening of flue join, and the other end of exhaust opening is equipped with smoke discharging pipe, has air-introduced machine on the smoke discharging pipe, utilizes the air-introduced machine extraction of will discharging fume, and the temperature of the smoke evacuation of extraction is generally more than 100 degree.

When coal combustion, the NO in the combustion products_xGeneration and temperature extremely close relation is arranged, when the main furnace chamber temperature of boiler low more, NO in the combustion process_xGeneration few more.

For the temperature that reduces main furnace chamber to reduce NO_xGeneration, smoke evacuation is set between the blast orifice of the smoke discharging pipe of boiler and boiler introduces pipeline, flue gas and fresh air are mixed into the boiler air blast, carry in the direction main furnace chamber under the chain by air blast.The flue-gas temperature of introducing from smoke discharging pipe is more than 100 ℃, and sneaking into of flue gas can make the temperature of air blast improve about 40-50 ℃, improved the overall efficiency of boiler.The oxygen content of flue gas is about 11%, be lower than in the air 20.9% oxygen content, since blending in the air blast of flue gas oxygen content low, slowed down the burning velocity of coal cinder, thereby reduced the temperature of main furnace chamber, by the ratio between flue gas and the fresh air in the adjustment air blast, control the oxygen content in the air blast, control burning of coal speed, thus the main furnace chamber temperature reduced, thus reduced NO_xA large amount of generations.

Air-introduced machine delivery outlet one side of smoke exhaust pipe is a malleation to the smoke discharging pipe between the floss hole of smoke exhaust pipe, and the smoke evacuation outlet just is arranged in this zone, and smoke evacuation utilizes the malleation in the smoke discharging pipe to enter automatically in the bleed pipeline that links to each other with boiler blower.Because the introducing of flue gas has reduced the oxygen content in the boiler air blast, can bring the increase of coal-fired imperfect combustion heat loss, i.e. CO and C_mH_nConcentration Deng fuel gas increases, and the present invention utilizes pneumatic injection principle to install unpowered blower unit additional in the appropriate location of boiler, and new wind is introduced in the boiler, and unburnt CO and C further burn_mH_nDeng combustible, reduce NO to be implemented in_xIn the time of discharging, do not influence the efficiency of combustion of boiler.

Among Fig. 1-2, in an end of themain furnace chamber 1 of horizontal chained coal fired boiler and Heat Room 2 flare all, along on the airflow direction, the area of section ofmain furnace chamber 1 dwindles gradually, and the area of section of Heat Room 2 increases gradually.Be provided withhermetic sealing substrate 3 betweenmain furnace chamber 1 and Heat Room 2, airtight the linking together of inwall of the periphery ofhermetic sealing substrate 3 andmain furnace chamber 1 thoroughly separatedmain furnace chamber 1 and Heat Room 2.And onhermetic sealing substrate 3, have four throughholes 6 that are communicated withmain furnace chambers 1 and Heat Room 2,main furnace chamber 1 be separately installed with two bleed pipelines 4 that communicate with the external world up and down, the air outlet 5 of bleed pipeline 4 is near throughhole 6 places.Fume pipe 7 is installed in the Heat Room 2, and water pipe 8 is coiled on the outer wall of fume pipe 7.

In the present invention, bymain furnace chamber 1 is designed to two horn mouths that link to each other with the junction of Heat Room 2, this structure has been accelerated flue gas in themain furnace chamber 1 to the flowing velocity of Heat Room 2, has increased the negative pressure degree in the main furnace chamber 1.Under the effect of negative pressure, new wind is inhaled in themain furnace chamber 1 from the external world by bleed pipeline 4, new wind mixes with high-temperature flue gas, mixed gas is together by thethrough hole 6 on thehermetic sealing substrate 3, enter in the fume pipe 7 in the Heat Room 2, when flue gas with after newly wind mixes, the fuel gas in the flue gas fully burns, further improved the temperature of flue gas, and the water in the water pipe 8 is heated under the effect of high-temperature flue gas.

For fuel gas is fully burnt, need to regulate the proportionate relationship between new wind and the fuel gas, and the soakage of new wind is relevant with the flow velocity of the area of section ofhermetic sealing substrate 3 and flue gas, therefore, adjusthermetic sealing substrate 3 areas of section or the quantity of throughhole 6 or the area of section of throughhole 6, realize reaching rational proportion between the soakage of new wind and the fuel gas.

In addition, new wind intake can also be arranged on the interior flue of Heat Room, but the temperature of the flue gas at new wind intake place can not be lower than 700 ℃, because in the flue is negative pressure state too, negative pressure in the flue sucks the new wind in the external world in the flue automatically, has increased the oxygen content in the flue gas.After new wind is introduced, increased the oxygen content in the flue gas, unburnt combustible CO and C in the flue gas_mH_nFurther burning, CO and C in reducing smoke evacuation_mH_nConcentration does not influence the combustion thermal efficiency of boiler simultaneously.New wind introducing amount can realize automatic adjusting, guarantees the variation of boiler load.

The flue gas of conventional boiler in being discharged into atmosphere before, all can utilize alkali lye that flue gas is carried out desulfurization and handle, because alkali lye is to NO and NO₂Mist produce absorption near 1: 1, and do not absorb simple NO, therefore, conventional exhaust gas desulfurization processing method can't be removed the NO in the flue gas.Utilize the present invention that flue gas is introduced body of heater again, the NO in the flue gas_xWhen passing through in the boiler high-temperature region once more, have a certain proportion of decomposition, and as NO and NO₂The alkali lye of mist by sulfur removal technology the time, alkali lye is to NO and NO₂Mist produce absorption near 1: 1 because a part of NO has generated NO in burner hearth₂, alkali lye is again to NO and NO₂Mist have absorption near 1: 1, its chemical equation is as follows:

2NO₂+2MOH→MNO₃+MNO₂+H₂O

NO+NO₂+2MOH→2MNO₂+H₂O

2NO₂+Na₂CO₃→NaNO₃+NaNO₂+CO₂

NO+NO₂+Na₂CO₃→2NaNO₃+CO₂

Therefore, adopt this method effectively to play dual removal effect to NO.

Adopt this method, recycling by to flue gas reaches more than 45% the recycling amount of discharged flue gas, utilized the waste heat of discharging flue gas; Because the bulk temperature of burner hearth reduces, reduce NO_xDischarging, and, reduced the exhaust gas discharging total amount in the efficiency of combustion that does not influence boiler, realized denitrogenating purpose of energy saving.Simultaneously, because the maximum temperature of main furnace chamber reduces, external heat radiation reduces, and to reducing boiler heat loss, improves the overall efficiency of boiler.

Claims (8)

1, a kind of energy-saving method for denitrogenation of horizontal chained coal fired boiler is specially:

1) partial fume that is discharged in the boiler exhaust gas pipeline is introduced in the boiler blower, by adjust in the boiler blower the ratio of the flue gas of introducing and fresh air control oxygen content in the air blast, with coal-fired burning velocity in the control boiler, thereby realize to temperature controlling in the boiler main furnace chamber with to NO_xThe inhibition that generates;

2) in being not less than 700 ℃ zone, the temperature at the interface or in the exhaust gases passes in the Heat Room that boiler main furnace chamber and Heat Room intersect introduces new wind, the boiler atmosphere that new wind and main furnace chamber are discharged is mixed, and utilizes the oxygen in the new wind that the fuel gas in the described boiler atmosphere is fully burnt.

2, energy-saving method for denitrogenation according to claim 1, it is characterized in that, the described mode that flue gas is introduced in the boiler blower is idle introducing, the flue gas outlet is arranged on delivery outlet one side of boiler exhaust gas pipeline air exhauster, and the malleation of being drawn in the flue gas utilization smoke discharging pipe enters in the bleed pipeline that links to each other with boiler blower automatically.

3, energy-saving method for denitrogenation according to claim 1 is characterized in that, the oxygen in the described new wind also makes the part NO in the described boiler atmosphere further react and generates NO₂

4, energy-saving method for denitrogenation according to claim 1 is characterized in that, described fuel gas comprises CO and C_mH_n

5, energy-saving method for denitrogenation according to claim 1, it is characterized in that, the mode of the new wind of described introducing is idle introducing, and the negative pressure that at the interface or in the Heat Room inner gas passage temperature of new wind by described main furnace chamber and described Heat Room is not less than in 700 ℃ the zone is sucked automatically.

6, energy-saving method for denitrogenation according to claim 5, it is characterized in that, the new wind of described idle introducing is realized by hermetic sealing substrate is set, described hermetic sealing substrate is arranged on the gas channel of the main furnace chamber of described boiler and Heat Room intersection, hermetic sealing substrate reaches with the inwall of main furnace chamber and links to each other with the inwall of Heat Room is airtight, and hermetic sealing substrate is provided with the through hole of some perforation main furnace chambers and Heat Room; One bleed pipeline is used for from the external world gas in main furnace chamber and introduces new wind, and the air outlet of described bleed pipeline is arranged in the main furnace chamber, and the new wind of introducing passes through hole and enters in the Heat Room with after the boiler atmosphere in the main furnace chamber is mixed.

7, energy-saving method for denitrogenation according to claim 6 is characterized in that, controls the resh air requirement of introducing by the control valve of regulating described bleed pipeline.

8, energy-saving method for denitrogenation according to claim 7, it is characterized in that, by regulating the number of openings on the described hermetic sealing substrate or the area of section of through hole, the flow velocity of adjusting boiler atmosphere in the main furnace chamber to be changing the negative pressure degree in the Heat Room, thereby changes the resh air requirement of introducing.

Images