SU1477978A1 - Method of burning gas - Google Patents

Abstract

The invention makes it possible to reduce the content of harmful impurities in the combustion products. Opposite gas-air streams are fed into the combustion zone by several fluxes and above them secondary air is introduced by jets along with sprayed water. In addition, recirculation gases are introduced into the combustion zone, secondary air is supplied by central swirling and peripheral continuous jets, and a part of the sprayed water is supplied together with air from gas-air streams. One part of the recirculation gases is pre-mixed with continuous-flow streams of secondary air, and the other is fed around all of its continuous streams. The sprayed water is supplied to the central swirling jets of secondary air in a number of 80 ... 90% of the total amount of water, and the recirculation gases are fed to the combustion zone with a recirculation coefficient of 5 ... 18%. 2 hp f-ly, 3 ill.

Description

one

The invention relates to power engineering, is intended for staged combustion of fuel in various fire engineering installations, mainly for power boilers and furnaces, and can also be used in the chemical, petrochemical and other industries.

The purpose of the invention is to reduce the content of harmful impurities in the combustion products.

Figure 1 shows the boiler furnace; FIG. 2 shows the change in the relative concentration of nitrogen oxides, depending on the amount of injected water (b, and b) in the secondary air of the total amount of water; FIG. 3 shows the change from the flue gas recirculation coefficient (g).

The method can be implemented in a boiler furnace comprising a housing 1, a combustion chamber 2, burners 4 in two engines located on the vertical walls 3 combustion chambers 2 and common air supply boxes 5 and recirculating flue gases 6 into the burners. The burners 4 have a central air duct 7 seconds

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a whirl 8, a peripheral air flow channel 9, a gas discharge unit 10 and an outer annular channel 11 of flue gases with a shell 12 made with holes 13 for pre-mixing the flue gases with peripheral air flow. Above (upper burner tiers 1A, secondary air nozzles 15 are installed with a central air channel 16 with swirlers 17 and a continuous peripheral channel 18. Secondary air nozzles 15 are also provided with external channels 19 for supplying recirculated flue gases and holes 20 in the shell 21 for preliminary ballasting of peripheral flow air of secondary air nozzles 15. In burners 4 and secondary air nozzles 15, water nozzles 22 with fittings 23 are installed. Air is supplied to the furnace by means of valves ora 24 and the flue gases circulating PE - exhauster 25 via the recirculated gases.

Example 1. A proposed gas combustion method is investigated on a 800 MW boiler. The burners 4 supply gas with central swirling and peripheral continuous primary air flow, as well as flue gases through channels 11 and water through nozzles 22. Water consumption (L,) varies from 0 to 25%. A central swirling secondary air stream is fed into the secondary air nozzles 15, and water (b) is injected in an amount of 70-95% of the total amount.

0

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0

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flue gas recirculation rates.

EXAMPLE 2. Similarly to the regimes described in Example 1, the effect of the recirculation coefficient g of flue gases on the emission of nitrogen oxides is investigated at optimal values bj x 15% and L "85%. The effect of the recirculation coefficient g at g 1 5% and g 18% on the concentration of nitrogen oxides in the combustion products is weak (Fig. 2). The largest decrease is observed at r 5–18% and is 10–40%. A decrease in r - 5% may lead to a loss of reliability of the furnace due to the cooling of the end elements of the outer channels 11 of the burners and the channel 19 of the secondary nozzles 15, and the increase in g is 18% leads to an increase in flue gas temperature and loss of boiler efficiency.

The combined use of water intake, the proposed staged combustion and recirculating flue gas gases makes it possible to achieve more than a threefold decrease in the concentration of nitrogen oxides.

Claims (2)

1. A method of burning gas by introducing secondary air into the combustion zone with several tiers of oncoming gas-air flows and introducing secondary air with sprayed water above them with counter-streams. Peripheral streams of primary air-containment of harmful impurities in the product in the burners 4 and nozzles 15 are pre-ballast with flue gases passing through the holes 13 and 20, due to the ejection of high-speed air flow. Studies have shown that with different recirculation ratios g 5, 10 and 15% (Fig. 2 a-b) the reduction of the concentration of nitrogen oxides is 2 to 3 times relative to the initial concentrations without stepwise combustion and without water injection. The optimal amount of injected water into the air of gas-air streams and secondary air (LO and (B) is respectively 0–20 and 90–80% (FGS, 2) 0 Outside of these values, the concentrations of nitrogen oxides sharply increase at various concentrations 55 In addition, recirculation gases are additionally introduced into the combustion zone, secondary air is supplied by central behind twisted and peripheral continuous jets, and part of the sprayed water is supplied together with air from gas-air streams, one part of the recirculation gases is preliminarily mixed with direct secondary air streams, and the other is fed around all its continuous streams, i 2. The method of pop. 1, which differs from the fact that the sprayed water is supplied to the central swirling jets of secondary air in the amount of 80–90% of the total amount of water. five 0 five In addition, recirculation gases are additionally introduced into the combustion zone, secondary air is supplied by central swirling and peripheral continuous streams, and part of the sprayed water is supplied together with the air-gas streams, while one part of the recirculation gases is preliminarily mixed with continuous streams secondary air, and the other is served around all its continuous flows, i 2. The method of pop. 1, which differs from the fact that the sprayed water is supplied to the central swirling jets of secondary air in the amount of 80–90% of the total amount of water. ///////// Z ////// // 7 /////////////// LU ////, Air d / mob / e recirculated / existing gases25 1 Cm  MI, THAT 75 €  //////////////// l 119 2018 to L ten Js Zo +% 8085 And) ig1 90  5 70  5 ° /, z: 85% Compiled by M.Vatsuro Editor And „Derbak Tehred L.Oliynyk Proofreader S.Cherni Order 2347/37 Circulation 489 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 75 Fig.Z es r,% Subscription