SU1477977A1 - Method of burning fuel - Google Patents

Abstract

The invention can be used for staged fuel combustion in the chemical, petrochemical industry. The purpose of the invention is to reduce the content of harmful impurities in the combustion products. In the combustion zone, the air-fuel mixture is supplied with two Dusas with an excess air coefficient in the lower rhea α _H * 981, and in the upper rusa α _B * 981. Flue gas and sprayed water flows are also introduced into the combustion zone, and a co-axial air stream that is coaxially and inclined at an angle downward is introduced into the lower-rush air-fuel mixture flow. In this case, the flue gases are fed in a mixture with additional air, the proportion of which in the coaxial stream is equal to 13 ... 17%, and in the inclined stream - 15 ... 20% of the total air flow. The sprayed water is injected into the air-fuel flows with the same distribution of its flow in the Rus. 1 hp f-ly, 8 ill.

Description

The invention relates to power engineering and is intended for staged combustion of fuel in various fire engineering installations, mainly for power boilers, furnaces, and can 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; figure 2 - change the temperature of the torch according to the relative height of the furnace; FIG. 3 shows the change in the concentration of molecular oxygen according to the relative height of the furnace; figure 4 - curves of the degree of burnout of fuel by the relative height of the furnace; figure 5 - j, the change in the concentration of nitrogen oxides in the relative height of the furnace; figure 6 - the change in the concentration of benzo (a) pyrene in the relative height of the furnace; Fig. 7 shows curves of changes in the concentration of nitrogen oxides at various coefficients of excess air at the outlet

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de from the firebox and the supply of various amounts of additional air and flue gases; Fig. 8 shows concentration variation curves. Benzen (a) pyrene at different coefficients of excess air at the exit from the furnace and when different amounts of air and flue gases are supplied.

The proposed method is implemented in a boiler furnace, comprising a housing 1, burners 2 for feeding combustion products from, burners 3 for feeding combustion products from ci 1, slots 4 for

supplying additional air in the axial direction opposite to the combustion products of burners 2, apparatuses 6 and 7 for water injection, exhaust fan 8, recirculation of flue gases, blow fan 9

Example 1. Figures 2-4 (curves A) depict the curves of changes in the temperature of the plume, the concentration of molecular oxygen and the degree of fuel burnout by the relative height of the furnace during stoichiometric combustion, i.e. when applying the entire amount of fuel and air through the burners 2 and 3 (figure 1). Figure 5 and 6 (curves A) shows the concentration of oxides of nitrogen and the concentration of ben (a) pyrene.

PRI mme R 2. A method of burning fuel, consisting in supplying additional air by opposite flows in an amount of 13-17% through slots 4 of the total air flow "In this mode of combustion, on all curves representing the temperature change of the flame, the concentration of molecular oxygen , the degree of fuel burnout, jumps occur (Figures 2-4, curve B), which indicate an intensification of the combustion process at the time of oncoming air supply. As a result, the formation of nitrogen oxides increases slightly and the concentration of benzo (a) pyrene decreases (Figures 5 and 6, curves B) as compared with the stoichiometric combustion mode (Figures 5 and 6, curves A).

Example The method of fuel combustion, which consists in supplying the fuel-air mixture flows through the 2iSss burners (, S1IOs 1 and additional air through the slots 5 in the amount (15-20%) of the total air flow at an acute angle down to zone from 1. In this mode of combustion temperature and burnout top

ten

15

20

779774

The width of the flame is reduced by x (fig. 2-4, curves B). This leads to a decrease in the formation of nitrogen oxides in the plume and to an increase in the formation of benzo (a) pyrene (Figures 5 and 6, curves B). At the time of supplying additional air, 13-17 and 15-20%, respectively, along the axis and at an angle downwards through slots 4 and 5, the combustion process is intensified (Figures 2-4, curves D) without a significant increase in the formation of nitrogen oxides (Fig.5 , curve B), however, the concentration of benzo (a) pyrene in this case exceeds the level obtained in examples 1 and 2 (Fig. 6, curve B).

Example p4. The method of burning fuel in the boiler furnace, which consists in supplying additional air through the slots 4 and 5 into the flows of the components of the combustion with about. 1 mixed with recirculated flue gases in axial and acute angles downward, respectively, with the axial air jet ratio being- (13-17 /% the inclined air jet J ratio is 5–20% of the total air flow rate water into combustion streams with 1 and eЈ 1 respectively and equal to 1-1.5% of fuel consumption. staged oxygen supply to the combustion zone The flame temperature and fuel burnup rate rise slowly (Figures 2-4, Curves D) and create the best conditions for reducing the formation of nitrogen oxides (Figure 5, Curve D). Flowing air-to-air mixtures 1 and nL.1 of water in the sprayed form in the amount of 1-1.5% of fuel consumption leads to the dissociation of water with the formation of active centers, significantly increases the burning rate at the early stages

thirty

35

40

45

days x, and also leads to the destruction of the original hydrocarbons, including benzo (a) pyrene (Fig.6, curve D). In this case (Fig. 7 and 8), CNO) f and the concentration of benzo (a) pyrene varies greatly from excess air at the outlet of the furnace, the optimal values lie within the indicated ratios, and beyond these ratios the effect decreases. When submitting additional

Ea / black gases

Phage.1

0.2 QM 0.6 0.8 1, OhlHr FIG. 2

0.2 0, C 0.6 0.8 1p h / It Fiz.Z fl

 sixteen

0.1 0.4 0.6 0.8 1.0 MNt Fig.Ch

0.2 0.4 0.6 0.8 1pH / Nt

0.2 0.4 0.6 0.8 p.h / Nt FIG. 6

Cf / ox mg / m 1000

800600m 200SH 1.04 W6 1fl8 AT Thebes. 7

1.02

AT

Claims (2)

Claim 1. The method of burning fuel by 10 supply to the combustion zone with two tiers of air-fuel mixture flows with an excess air coefficient in the lower tier with £ _m <1 and in the upper tier <>! · &> 1, and introducing smoke-x flows into the combustion zone 15 exhaust gases and atomized water, characterized in that, in order to reduce the content of harmful impurities in the combustion products, it is counter to the flow of the air-fuel mixture of the lower 2o tiers introduce additional coaxial and inclined at a downward angle jets of additional air, while the flue gases are mixed with additional air, the proportion of which in the coaxial stream is 13-17% 25 and inclined - 15-20% of the total air flow. 2 ”The method of Pop. 1, with the fact that the sprayed water is introduced into the fuel and air flows with 30 equal distribution of its flow in tiers. 1,477,977 ' FIG. 8