CN101839473A

CN101839473A - Flue gas recirculation high temperature air energy-saving and environmental protection combustion technology

Info

Publication number: CN101839473A
Application number: CN200910037908A
Authority: CN
Inventors: 不公告发明人
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-03-16
Filing date: 2009-03-16
Publication date: 2010-09-22

Abstract

The invention relates to a technology of combustion, in particular to a flue gas recirculation high-temperature air energy-saving and environmental protection combustion technology which is applied to the boiler combustors such as utility boilers, industrial boilers, metallurgical heating furnaces and the like. The invention adopts the concept of flue gas recirculation combustion, realizes real oxygen-poor high-temperature combustion, stabilizes theoretical flame temperature, creates the reducing flue gas environment, reduces oxidation combustion loss, reduces generation of NOX in two-way, and greatly saves fuel. The invention not only saves energy and reduces emission, but also achieves nitre reduction.

Description

Flue gas recirculation high temperature air energy-saving and environmental protection combustion technology

Technical field

The present invention relates to the combustion technology in a kind of boiler combustion equipment, particularly widely used flue gas recirculation high temperature air energy-saving and environmental protection combustion technology on stove, ceramic stove or the like burner at the bottom of Industrial Boiler, smelting and heating, hot-blast stove, the roller.

Background technology

Along with the raising day by day of environmental requirement, desulfurization, denitration are extensively paid attention to, and desulfurization is mainly implemented in the coal-burning power plant, and out of stockly just not only need to implement at station boiler, at the general industry stove, all need to implement as cement rotary kiln, smelting and heating or the like.If can control pollutant, can ease off the pressure and cost to administering link undoubtedly in the initial link of producing.

Conventional boiler or heating furnace burner, its combustion system are simply, inefficient combustion.Be characterized in fuel and air by slowly and passive mode mix and finish combustion process, during this time, fuel-side, as be light Fuel, then spray into burner hearth with the normal temperature state, heavy fuel is (as coal dust, heavy oil) can be heated to and be beneficial to the temperature (below 300 ℃) of lighting, the then most of situation of gaseous fuel is then burnt with environment temperature, be used for combustion-supporting air then most applications enter body of heater burning with environment temperature, large-sized boiler is equipped with air heat exchanger, but even if air heat exchanger is arranged, because of its heat transfer rate mostly is 40%, air preheating temperature usually can be above 400 ℃.Theoretical proof: 100 ℃ of the every raisings of air themperature, capable of saving fuel 5%.Because the flame radiation calorific intensity is directly proportional with the biquadratic of flame temperature, therefore, adopt high-temperature air combustion promoter, can reach fuel-saving purpose.

But simple high-temperature air burning, fuel can reach 2400 ℃ of its theory (thermal insulation) flame temperatures, so high flame temperature is easy to form hot-spot in the stove, and coal-powder boiler forms the burner coking easily, especially to smelting and heating, it is very serious that the oxidization burning loss of steel billet will become, influence the billet surface quality, output also can descend thereupon, simultaneously, no matter to which kind of boiler, all higher NO can appear _XProduction rate.Because NO _XGenerating all is the heating power type, is difficult at low temperatures generate, and why the Fire Radiation ability rises with temperature, and the radiation effects that a crucial factor is exactly NO begins to manifest, just N ₂At high temperature begin and O ₂Reaction.Rely on burner self smoke backflow to suppress NO _XGeneration only exist in theory may, have very strong randomness, do not have quantizating index.NO _XTo human body harm super SO far away ₂, mainly from airborne N ₂, it can influence central nervous system, and airborne vehicle such as airline carriers of passengers can produce NO _X, but its height of release is higher, more than 10000m, human body is not had direct influence, but the general industry boiler chimney is lower, NO _XCan fall earthward, enter human body with breathing.So must be paid much attention to, be reduced its generation rate as far as possible.

How, can prevent boiler coke, can reduce the workpiece oxidization burning loss again, can fundamentally suppress NO again realizing the fuel-saving while _XGeneration? attenuating is to environment, to the infringement of human body, and a kind of novel combustion technology is arisen at the historic moment, the high wind-warm syndrome energy-saving and environmental protection combustion technology of flue gas recirculation that Here it is.

Summary of the invention

Flue gas recirculation high-temp combustion technology realizes real oxygen deprivation high-temp combustion, stabilizes theoretical flame temperature, and significantly fuel savings is created reproducibility flue gas environment, reduces oxidization burning loss, two-way reduction NO _XGeneration.Both energy-saving and emission-reduction realize subtracting nitre (NO again _X).

Description of drawings

Accompanying drawing is the view of flue gas recirculation high temperature air energy-saving and environmental protection combustion technology of the present invention.

The specific embodiment

Flue gas recirculation high temperature air energy-saving and environmental protection combustion technology is that the flue gas after the fuel combustion is heated into high-temperature gas again after combustion air mixes, and burns with fuel again.

With reference to the accompanying drawings content of the present invention is further elaborated:

As shown in the figure, duplexing gas channel of close arrangement each side in the original burner position of boiler setting 13, be respectively 1 passage and 2 passages, two passes adopts full-duplex mode, during the work beginning, by-pass valve control 3 is opened, passage 1 begins to aspirate the high-temperature flue gas on burner 12 left sides under the effect of air-introduced machine 7, the flue gas stream loop body 10 of at first flowing through, and be cooled and reduce to about 150 ℃, therefrom draw by air-introduced machine 7, after keeping certain hour, by-pass valve control 6 is opened, and under the guiding of air-introduced machine 7, passage 2 begins to suck the flue gas on burner 12 the right, and process is identical with passage 1; Meanwhile, when passage 2 is air-breathing, under air blast 8 excitations, low temperature combustion air 9 is compulsorily entered into loop body 10, after being heated, this strand air-flow becomes high-temperature gas (about 900 ℃～1100 ℃) in loop body 10, enter burner 12 left side passages 1 air channel subsequently, in stove with the burning of meeting of the fuel of former burner 12 burners ejection; Same, when passage 1 was air-breathing, combustion air 9 was by same air blast 8 excitations, force to enter loop body 11, and in loop body 11, be heated to form high temperature gas flow, enter former burner 12 right-side channels 2 air channels subsequently, in stove with the burning of meeting of the fuel of former burner ejection, so, whole process moves in circles, like this, the combustion air of supplying with burner just becomes the high temperature combustion air by low temperature, simultaneously, the direct discharging of former high-temperature flue gas also becomes discharged at lower temperature in the stove, has greatly reclaimed obvious heat of smoke.

As shown in the figure, the low-temperature flue gas after air-introduced machine 7 discharged by pipeline and device 14 with do not fire combustion air 9 and mix, be sent to

loop body interior

10 or 11 interior high-temperature process simultaneously, participate in fuel combustion then, just become the flue gas recirculation high-temp combustion.

The Main Ingredients and Appearance of flue gas is: CO ₂, H ₂O, N ₂, SO in the flue gas ₂Generation relevant with the content of sulphur in the fuel, NO _XGeneration closely related with fired state, remaining is the inorganic salts ash content then, drains with tapping process.

The flue gas Main Ingredients and Appearance that produces after the common fuel combustion is CO ₂, H ₂O, N ₂, can contain the O of certain volume under greater than 1 situation at excess air factor ₂, complete for guaranteeing fuel combustion in the combustion system design, do not produce CO, all must make excess air factor greater than 1, in other words, to keep oxidizing atmosphere exactly, excessive O ₂Though can be with the fuel after-flame, but can make the flame temperature after the burning obvious low excessively, flame power is less than normal, programming rate is slow, the fuel service efficiency is low, and it is longer that fuel drops into burning time, is low-calorie fuel if use, can't after-flame, waste greatlyyer, easilier cause workpiece oxidization burning loss in the burner hearth, cause that output and quality is two to descend.

Adopt the flue gas recirculation combustion technology, with the neutral gas after the burning-weary gas, with after the blending of fresh unburned air again with fuel combustion, reduced the oxygen content in the live gas, its volume ratio will decline to a great extent by 21%, because weary gas does not participate in burning, whole like this combustion process just becomes genuine combustion with meagre oxygen environment, because the oxygen volume ratio descends, air-fuel ratio must become greatly as can be known, and residual air increases, and flame temperature must reduce, hot-spot can be obviously suppressed, and NO can be significantly reduced _XGeneration.Owing to adopt high-temperature air burning, combustion air has very high activation energy, the fuel electrodes easy firing again.

For some low calorific value gas fuel, also it can be carried out high-temperature process, and then burn.

Adopt the benefit of above-mentioned way to be:

1. method is simple, and is easy to implement, with the burner physical location as the transformation center, each burner separate configurations;

2. do not have the thermal technology to get in touch between the adjacent burner, more need not be cascaded to the burner of offside, pipe network is simple, move towards clear, and the duration is short, and is easy to implement, installs, easy to maintenance;

3. the combustion air excess coefficient is less than 1, and this is difficult to reach in the ordinary course of things, and air consumption reduces thereupon, and exhaust smoke level descends, and the flue gas heat loss reduces naturally;

4. can control and reduce the temperature of combustion flame, it is scorching hot to the localized heat that the is heated workpiece problem that rises thoroughly to have solved single temperature field in furnace inequality, localized hyperthermia and flue gas that is formed by HTAC;

5. combustion-supporting oxygen concentration is controlled and far below 21%, the real combustion with meagre oxygen of realizing can be controlled and guarantee to be reducing atmosphere in the stove, thereby has thoroughly avoided the workpiece oxidization burning loss that caused by overheated and excess oxygen, improve Related product output and quality, improve the core competitiveness of enterprise;

6. can control and reduce the temperature of combustion flame, thoroughly solve the NO that brings by high-temperature air burning _XToo high problem;

7. flue gas recirculation process is a negative feedback process to combustion system;

8. can significantly reduce fuel consumption;

9. both energy-saving and emission-reduction, environmental protection subtracts nitre again, achieves many things at one stroke.

Claims

1. flue gas recirculation high temperature air energy-saving and environmental protection combustion technology is characterized in that the flue gas after the fuel combustion enters the burner hearth burning with the fresh combustion air that will participate in burning.

2. flue gas recirculation high temperature air energy-saving and environmental protection combustion technology according to claim 1 is characterized in that circulating flue gas can a part enter burner hearth participation burning, also can all enter the burner hearth burning.

3. flue gas recirculation high temperature air energy-saving and environmental protection combustion technology according to claim 1, it is characterized in that flue gas can be high temperature also can be low temperature.

4. flue gas recirculation high temperature air energy-saving and environmental protection combustion technology according to claim 1 is characterized in that flue gas can mix with air at the cold junction of combustion air, also can mix with hot-air in the hot junction.

5. flue gas recirculation high temperature air energy-saving and environmental protection combustion technology according to claim 1 is characterized in that valve sets can be a combination of monomers, also can be integrated form.

6. flue gas recirculation high temperature air energy-saving and environmental protection combustion technology according to claim 1 is characterized in that the position between passage 1 and passage 2 and the burner can be a left-right symmetry, also can be four-way diagonal angle symmetric arrangement.

7. flue gas recirculation high temperature air energy-saving and environmental protection combustion technology according to claim 1 is characterized in that flue gas can also can directly enter the burning of combustion air gas channel with high temperature without the loop body cooling through the loop body cooling.

8. flue gas recirculation high temperature air energy-saving and environmental protection combustion technology according to claim 1 is characterized in that flue gas except that fresh combustion air is implemented the blending, can also be to fuel, and especially gaseous fuel carries out blending.