CN103335303B - Vertical heater 3 D stereo classification OFA after-flame wind low nitrogen burning technology - Google Patents

Abstract

The invention discloses a kind of combustion system of Industrial Boiler, a kind of vertical heater 3 D stereo classification OFA after-flame wind low nitrogen burning technology is particularly disclosed, comprise burner hearth, adopt three grades of air feeds to complete burning, concrete grammar is, the arrangement of burner adopting is the burner of front wall and rear wall layouts that liquidate between two, and airduct and secondary air channel are relative level layout, and the air output of an airduct is 2200m³/ h, the air quantity of secondary air channel is 44500m³/ h, the wind pushing temperature of airduct and secondary air channel is 150 DEG C of wind-warm syndrome, secondary air temperature is 260 DEG C, combustion zone ignition temperature is controlled at 1600 DEG C, in the both walls of vertical boiler, be respectively arranged with two OFA spouts, four OFA spouts are same plane to be arranged, the air quantity of OFA spout is 8900m³/ h is provided with SOFA spout on the seamed edge of vertical boiler, does is the air quantity of SOFA spout 1500? m³/ h; The invention provides and make a kind of 40 tons of/hour vertical industrial pulverized coal boiler combustion utilization efficiencies improve and can effectively control the low nitrogen burning technology of discharged nitrous oxides.

Description

Vertical heater 3 D stereo classification OFA after-flame wind low nitrogen burning technology

Technical field

The present invention relates to a kind of combustion system of Industrial Boiler, particularly relate to a kind of vertical heater 3 D stereo classification OFA after-flame wind low nitrogen burning technology.

Background technology

Coal-burned industrial boiler is the main heat energy equipment of China, according to statistics, ends 2010, and sum reaches 60.12 ten thousand, and total capacity reaches 3,480,000 and steams ton, nearly 700,000,000 tons, year consumption coal. Coal-burned industrial boiler pollutant discharge amount is large, is only second to coal fired power generation, is the main emission source of cities and towns atmosphere pollution, is chain furnace or traditional coal-powder boiler all solve discharged nitrous oxides severe overweight problem without effective measures.

Nitrogen oxide is one of coal fire discharged pollutant, accounts for China NO_xThe more than 60% of total emission volumn, wherein coal-burned industrial boiler discharges approximately 2,500,000 tons. According to current discharge control level, to reach 2363-2,914 ten thousand tons to the year two thousand twenty China nitrogen oxide emission, to exceed the U.S. and become the first in the world discharged nitrous oxides state, therefore, the problem of controlling discharged nitrous oxides has been very urgent, and with respect to coal-fired power station boiler, industrial boilers in China is taking medium small boiler as main, quantity is many, distribution is wide, is important NO_xEmission source, at NO_xIn control, occupy critical role, existing to NO_xControl technology is mainly that burning optimization and flue gas post processing reduce NO_xTechnology, wherein burning optimization technology comprises low excess air burning, fuel-staged combustion, combustion technology and flue gas recirculation etc. again, 40 tons of/hour vertical industrial pulverized coal boilers also exist corresponding problem, and it is not also very desirable adopting said method effect, and fuel availability emission control bad and nitrogen oxide is undesirable.

Summary of the invention

For solving the problems of the technologies described above, the invention provides and make a kind of 40 tons of/hour vertical industrial pulverized coal boiler combustion utilization efficiencies improve and can effectively control the vertical heater 3 D stereo classification OFA after-flame wind low nitrogen burning technology of discharged nitrous oxides.

Vertical heater 3 D stereo classification OFA after-flame wind low nitrogen burning technology of the present invention, comprises body of heater and is arranged on the burner hearth in body of heater, and inner primary zone and the burning-out zone of forming of burner hearth, adopts three grades of air feeds to complete burning, and concrete grammar is as follows:

One-level air feed: the arrangement of burner of employing is the burner of front wall and the rear wall layout that liquidates between two, airduct and secondary air channel are that relative level is arranged, the air output of an airduct is 2200m³/ h, the air quantity of secondary air channel is 44500m³/ h, the wind pushing temperature of airduct and secondary air channel is 150 DEG C of wind-warm syndrome, and secondary air temperature is 260 DEG C, and combustion zone ignition temperature is controlled at 1600 DEG C;

Secondary air feed: be respectively arranged with two OFA spouts in the both walls of vertical boiler, four OFA spouts are same plane to be arranged, the air quantity of OFA spout is 8900m³/h；

Three grades of air feeds: be provided with SOFA spout on the seamed edge of vertical boiler, four are quadrangle tangential circle mode and arrange and be positioned at same plane, and the air quantity of SOFA spout is 1500m³/h。

Described OFA spout between SOFA spout and burner, and height tolerance be no more than ± 10%.

Described SOFA spout entirety is clockwise air feed.

Compared with prior art beneficial effect of the present invention is:

(1) owing to having taked three grades of air feed combustion technologies, thereby the nitric efficiency of 40 tons of/hour vertical industrial pulverized coal boilers is significantly improved, this technology makes final smoke evacuation containing NO_xReduction by 40% left and right that concentration ratio is original;

(2) NO in the flue gas of discharging_xConcentration control is not more than 150mg/m³, lower than the NO of national Specification_xMinimum discharge capacity.

Brief description of the drawings

Fig. 1 is the structural representation of vertical heater 3 D stereo classification OFA after-flame wind low nitrogen burning technology of the present invention.

Detailed description of the invention

Below in conjunction with drawings and Examples, the specific embodiment of the present invention is described in further detail. Following examples are used for illustrating the present invention, but are not used for limiting the scope of the invention.

As shown in Figure 1, a kind of vertical heater 3 D stereo classification OFA after-flame wind low nitrogen burning technology, comprises body of heater and is arranged on the burner hearth 3 in body of heater, and inner primary zone and the burning-out zone of forming of burner hearth 3, adopts three grades of air feeds to complete burning, and concrete grammar is as follows:

One-level air feed: burner 4 arrangements of employing are the burner 4 of front wall and the rear wall layout that liquidates between two, airduct and secondary air channel are that relative level is arranged, the air output of an airduct is 2200m³/ h, the air quantity of secondary air channel is 44500m³/ h, the wind pushing temperature of airduct and secondary air channel is 150 DEG C of wind-warm syndrome, and secondary air temperature is 260 DEG C, and combustion zone ignition temperature is controlled at 1600 DEG C.

Secondary air feed: be respectively arranged with 2, four OFA spouts 2 of two OFA spouts and be same plane layout in the both walls of vertical boiler, the air quantity of OFA spout 2 is 8900m³/h。

Three grades of air feeds: be provided with 1, four of SOFA spout and be quadrangle tangential circle mode and arrange and be positioned at same plane on the seamed edge of vertical boiler, the air quantity of SOFA spout 1 is 1500m³/ h, SOFA spout 1 entirety is clockwise air feed.

OFA spout 2 between SOFA spout 1 and burner 4, and height tolerance be no more than ± 10%.

General principle of the present invention is: the required air capacity of burning is divided into three grades and sends into burner hearth 3, make in main combustion zone excess air coefficient at 0.8-1, fuel first burns under rich fuel condition, burning velocity and temperature are reduced, postpone combustion process, the a large amount of growing amounts of x in main combustion zone that contain in reducing atmosphere, the required remaining air of burning is sent into burner hearth 3 by the OFA spout 2 and the SOFA spout 1 that are arranged in main burner top, after feeding after-flame wind, become burning-out zone, though now air capacity is many, but because of flame temperature low, and most of nitrogen-containing group of separating out in coal is anti-nitrogen groups and NO in primary zone_xReaction, has improved NO_xTo N₂Conversion ratio, having reduced NO should complete, final NO_xGrowing amount is little, and the infeed of air simultaneously makes the abundant after-flame of residual coke in pulverized coal particle, ensures the high burning efficiency of coal dust, and in final stove, vertical air fractional combustion can make NO_xGrowing amount reduces 30-40%.

The air capacity of effective supply and the ratio of theoretical air requirement when above-mentioned middle excess air coefficient refers to burning, i.e. the required theoretical air quality of air quality/completing combustion 1kg fuel of α=burning 1kg fuel institute effective supply.

Coal dust in combustion process, the reaction equation of the main source of nitrogen oxide in coal-fired process:

HCN+O₂→NO_x+……(1)

NH₃+O₂→NO_x+……(2)

Cf-N+O₂→NO_x+……(3)

On the other hand, after coal dust is heated, pyrolysis and oxidation reaction process exist simultaneously, the CH being separated out by pyrolysis_i, HCN and NH_jAll reducible NO_x, reactional equation is:

CHi+NO_x→HCN.....(4)

HCN+O.OH→N₂+……(5)

NO_x+NHj→N₂…(6)

The process that simultaneously also has complicated vapour phase reduction NO and heterogeneous reduction NO, the heterogeneous mechanism in coke surface is:

2NO_x+2(C)→N₂+2CO(7)

(C)+2NO_x→CO₂+N₂(8)

From above formula, the generation of NOx and reduction mechanism are known, and under the condition of oxygen deprivation, the N in fuel is with HCN, NH₃、NO_xExist etc. form, the NO of generation can with gas phase in the generations homophase reduction reaction such as reducing substances CH, HCN, NH and reduce and change into N in coke surface₂, realized the low NO of coal dust_xBurning, under the condition of oxygen enrichment, the reducing substances in gas phase and coke and O₂Generation oxidation reaction is consumed, and the N in fuel is easy to be converted into NO_x, be unfavorable for NO_xReduction of discharging, though now air capacity is many, because flame temperature is low, and most of nitrogen-containing group of separating out in coal reacted in oxygen-depleted zone, final NO_xGrowing amount is little, and the infeed of air simultaneously makes the abundant after-flame of residual coke in pulverized coal particle, ensures the high burning efficiency of coal dust, and in final stove, vertical air fractional combustion can make NO_xGrowing amount reduces 30-40%.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, do not departing under the prerequisite of the technology of the present invention principle; can also make some improvement and modification, these improve and modification also should be considered as protection scope of the present invention.

Claims (2)

1. a vertical heater 3 D stereo classification OFA after-flame wind low nitrogen burning method, comprises body of heater and is arranged on the burner hearth in described body of heater, it is characterized in that: inner primary zone and the burning-out zone of forming of described burner hearth, and adopt three grades of air feeds to complete burning, concrete grammar is as follows:

One-level air feed: the arrangement of burner of employing is the burner of front wall and the rear wall layout that liquidates between two, airduct and secondary air channel are that relative level is arranged, the air output of an airduct is 2200m³/ h, the air quantity of secondary air channel is 44500m³/ h, the wind pushing temperature of airduct and secondary air channel is 150 DEG C of wind-warm syndrome, and secondary air temperature is 260 DEG C, and combustion zone ignition temperature is controlled at 1600 DEG C;

Secondary air feed: be respectively arranged with two OFA spouts in the both walls of vertical boiler, four OFA spouts are same plane to be arranged, the air quantity of OFA spout is 8900m³/h；

Three grades of air feeds: be provided with SOFA spout on the seamed edge of vertical boiler, four are quadrangle tangential circle mode and arrange and be positioned at same plane, and the air quantity of SOFA spout is 1500m³/h。

2. vertical heater 3 D stereo classification OFA after-flame wind low nitrogen burning method as claimed in claim 1, is characterized in that: described SOFA spout entirety is clockwise air feed.