RU2076271C1 - Device for burning gaseous fuel - Google Patents

Abstract

FIELD: power engineering, chemical, petrochemical and other industries. SUBSTANCE: device has cylindrical housing 1, fuel oil burner 2, central air passage with swirlers 3, swivel gas dispensing tubes 4 combined in manifolds 5 and 6, peripheral circular air passage 7 with swirlers 8, gate valve 9 for distributing the air among passages 7 and central air passage. Gas dispensing tubes 4 are fitted between central air passage and peripheral passage 7. Outlet holes of gas dispensing tubes are located tangentially and radially relative to axis of air passage: ratio of diameter of circle on which gas dispensing tubes are located to inner diameter of housing 1 ranges from 0.45 to 0.70 and ratio of total area of holes located tangentially and radially ranges from 0.5 to 1.0. EFFECT: enhanced reliability. 2 dwg

Description

 The invention relates to energy and can be used to burn gaseous fuels, also in the chemical, petrochemical and other industries.

A device containing a combustion chamber, burners located in two tiers and nozzles of sharp blasting of tiers, using which a method of burning fuel is known [1]
During the operation of the device, fuel and the main part of the air necessary for the combustion of this fuel are supplied through the burners. The remaining air is supplied through sharp blast nozzles.

 The operation of burner devices with sharp blast nozzles is carried out with a relatively large lack of air (low air speed), which affects the control characteristics of the burner and the preparation of air fuel mixture formation.

The closest to the invention in technical essence and the achieved result is a device for burning gaseous fuel of the company "Steinmuller", containing a cylindrical body in which there are central and peripheral air channels with swirls, rotary gas distribution tubes with outlet openings installed between the air channels and located tangentially and radially to the axis of the air channel, while the gas distribution tubes are connected to a common collector [2]
A disadvantage of the known device is the imperfect mixture formation of gaseous fuel with air, leading to an insufficient level of reduction in the concentration of nitrogen oxides in the combustion products.

 The objective of the invention is to provide a device for burning gaseous fuels, which allows to increase the level of reduction in the concentration of nitrogen oxides in the combustion products.

 The problem is solved in that in a device for burning gaseous fuel containing a cylindrical body in which are parallel and peripheral air channels with swirls and rotary gas distribution tubes installed between the air channels, the outlet openings of which are located tangentially and radially to the axis of the air channel, the diameter of the circle on which the gas distribution tubes are located to the inner diameter of the housing is 0.45 0.70, and the ratio of the total output area tversty tangentially and radially arranged gazorazdayuschih tubes is 0.5 1.0, wherein gazorazdayuschie tube radially and tangentially disposed openings are connected to different reservoirs.

 Distinctive features from the prototype signs aimed at increasing the level of reduction of the content of nitrogen oxides in the combustion products, in known sources of information are not found.

 A comparison of the proposed solution with other technical solutions shows that, in the authors' opinion, it does not explicitly follow from the prior art, since the influence of the ratios characterizing the relative position of the fuel and air jets and the ratio of the fuel jet flow rates the combustion zone radially and tangentially, to reduce the content of nitrogen oxides in the combustion products. The claimed device, based on a decrease in the concentration of oxygen in the combustion zone, is simpler to implement than conventional ones using flue gas recirculation (ed. St. USSR N 1477978, class F 23 c 11/00, 1987), or inert gases (ed. St. USSR N 630488, F 23 c 11/00, 1976). This allows us to conclude that the claimed method and device for burning gaseous fuels meets the eligibility criteria of "novelty" and "inventive step".

 In FIG. 1 is a general view of a device that implements a method for burning gaseous fuel, and FIG. 2 shows a diagram of the direction of gas jets relative to the cross section of the central jet.

 A device for burning gaseous fuel contains a cylindrical body 1, a central air channel 2 with swirls 3 and rotary gas distribution tubes 4 combined into collectors 5 and 6, a peripheral annular air channel 7 with swirl 8, a gate 9 for distributing air between channels 7 and 9.

 Gas tubes 5 are installed between the air channels 2 and 7, the outlet openings of which are located tangentially and radially to the axis of the air channel, the ratio of the diameter of the circle on which the gas distribution tubes are located to the inner diameter of the housing 1 is 0.45 0.70, and the ratio of the total area output tangentially and radially spaced openings of gas distribution tubes is 0.5 1.0.

 The device operates as follows.

 Air is supplied to the cylindrical body 1. Air enters in a single stream through the central air channel 2, where it is twisted by means of a swirler 3, forming a central swirling stream. Gaseous fuel is supplied to the gas distribution tubes 4 through the manifolds 5 and 6, which is mixed with the air supplied through the central air channel 2 and ignited by an ignition device (not shown). Since the resulting gas-air mixture has an excess of gas, not all gas, but part of it, burns out in the initial section of the flare. Unburned gas is mixed with air, which is supplied through a peripheral channel 7 with a swirler 8, and the resulting combustible mixture burns out in subsequent zones of the torch. The regulation of the amount of air supplied to the channels is carried out using a gate 9 by turning it around its axis.

Природный газ подают в центральную воздушную струю отдельными струями таким образом, что все струи направлены радиально, т.е. N_танг./N_рад. O и F/f 0.Example 1. The gas flow rate of 0.05 m ³ / s. The ratio of the diameter of the circumference of the arrangement of the gas distribution tubes to the inner diameter of the housing is d / D 0.45. The number of gas distribution tubes 12. The tubes are combined into two collectors of 6 pcs. in each. The number of holes in each gas distribution tube 10 pcs. each hole diameter d _{of holes} 5 mm. The estimated gas flow rate will be

Natural gas is fed into the central air stream in separate jets in such a way that all jets are directed radially, i.e. N _tang. / N _glad. O and F / f 0.

Поскольку необходимый объем воздуха для полного сгорания 0,05 м³/с метана равен G $\genfrac{}{}{0ex}{}{\text{o}}{\text{в}}$ = 9,52•0,05 м³/с = 0,476 м³/с,, то количество воздуха, которое необходимо подавать через кольцевой канал, будет следующим:

При этом завихрители воздуха в центральном и кольцевом каналах обеспечивают параметры крутки центральной и кольцевой струи n₁ 5 и n₂ 5 (достигается путем установки соответствующих завихрителей). В этом случае параметр крутки сложной струи будет равен (соотношение 5)

При таком параметре крутки (В.В. Померанцев. Основы практической теории горения. Л. Энергоатомиздат, 1986, с. 41) обеспечивается рециркуляция продуктов сгорания вблизи устья горелки, что оказывает стабилизирующее воздействие на процесс воспламенения смеси (см. В.В. Померанцев, с. 145).Air is supplied through the central air channel and the peripheral annular channel. Air is supplied through the central air channel in such an amount that a gas-air mixture is formed with a gas concentration of not more than 15% (the maximum upper gas concentration in the mixture at which the mixture still ignites), i.e. air flow rate is

Since the required volume of air for complete combustion of 0.05 m ³ / s of methane is G $\genfrac{}{}{0ex}{}{\text{o}}{\text{in}}$ = 9.52 • 0.05 m ³ / s = 0.476 m ³ / s, the amount of air that must be supplied through the annular channel will be as follows:

In this case, the air swirls in the central and annular channels provide the twisting parameters of the central and annular jets n ₁ 5 and n ₂ 5 (achieved by installing the corresponding swirls). In this case, the twist parameter of the complex jet will be equal to (ratio 5)

With this twist parameter (VV Pomerantsev. Fundamentals of the practical theory of combustion. L. Energoatomizdat, 1986, p. 41), recirculation of combustion products near the mouth of the burner is provided, which has a stabilizing effect on the ignition of the mixture (see VV Pomerantsev , p. 145).

As is known (see V.V. Pomerantsev, p. 48), a vacuum is created near strongly swirling jets, which reaches (0.6-0.8) ρw $\genfrac{}{}{0ex}{}{\text{2}}{\text{o}}$ / 2 .. Therefore, for uniform mixing of gas and air, it is necessary to supply gas to the rarefaction zone, otherwise, a mixture with a lack of gas will form in this zone, which will disrupt the combustion process in the initial section of the flare. The supply of all gas provides the conditions for its uniform mixing with the air of the central jet due to reverse recirculation currents. If all the gas was supplied radially, and part of it was supplied tangentially, then with such twisting parameters (n 3,5), the part of the gas supplied tangentially would be carried away into the annular air stream due to the centrifugal effect, and therefore, in the initial section of the torch, create conditions for mixing with an excess of gas, which would in turn lead to the burning of a mixture with an elevated temperature and with an increased formation of nitrogen oxides.

то в последующих зонах факела сгорает

Пример 2. Расход газа 0,1 м³/с. Отношение диаметра окружности расположения газораздающих трубок к внутреннему диаметру корпуса составляет d/D 0,70. Количество газораздающих трубок 12. Трубки объединены в два коллектора по 6 шт. в каждом. Количество отверстий в каждой трубке 10, а диаметр каждого отверстия d_отв 5 мм.Since in our case, in our case, not all gas is burned, but only its following amount:

then in subsequent zones of the torch burns

Example 2. The gas flow rate of 0.1 m ³ / s The ratio of the diameter of the circumference of the arrangement of the gas distribution tubes to the inner diameter of the housing is d / D 0.70. The number of gas distribution tubes 12. The tubes are combined into two collectors of 6 pcs. in each. The number of holes in each tube 10, and the diameter of each hole d _resp 5 mm.

Так как необходимый объем воздуха для полного сгорания 0,1 м³/c газа равен G $\genfrac{}{}{0ex}{}{\text{o}}{\text{возд}}$ = 9,52•0,1 = 0,952 м³/с, то количество воздуха, которое необходимо подавать через кольцевой канал составит величину

Одновременно с подачей воздуха и газа в мазутную форсунку 2 подают мазут и зажигают мазутный факел, который воспламеняет смеси. После воспламенения смеси мазутный факел гасят.Natural gas is fed into the central air stream in separate jets in such a way that six jets are directed in parallel, and six jets are tangential, i.e., N _tang. / N _glad. one; F / f 1. Air is supplied through the central air channel in such an amount that a gas-air mixture is formed with a gas concentration of not more than 15%, i.e. air consumption will be

Since the required volume of air for complete combustion of 0.1 m ³ / s of gas is G $\genfrac{}{}{0ex}{}{\text{o}}{\text{air}}$ = 9.52 • 0.1 = 0.952 m ³ / s, then the amount of air that must be supplied through the annular channel will be

Simultaneously with the supply of air and gas to the fuel oil nozzle 2, fuel oil is fed and a fuel oil torch is ignited, which ignites the mixture. After igniting the mixture, the fuel oil torch is quenched.

При таком параметре крутки для равномерного смешения газа с воздухом центральной струи необходимо газ подавать таким образом, чтобы струи газа равномерно распределялись в струе воздуха, что возможно при подаче газа радиально и тангенциально с одинаковой интенсивностью, т.е. количество струй газа, подаваемых тангенциально, равно количеству струй газа, подаваемых радиально, т.е. газ подается во все стороны равномерно.Air swirls in the central and annular channels provide the twisting parameters of the central and annular jets n ₁ 0.7 and n ₂ 0.7

With this twist parameter, for uniform mixing of gas with the air of the central jet, it is necessary to supply gas in such a way that the gas jets are evenly distributed in the air stream, which is possible when the gas is supplied radially and tangentially with the same intensity, i.e. the number of jets of gas supplied tangentially equal to the number of jets of gas supplied radially, i.e. gas is supplied in all directions evenly.

Остальной газ сгорает в последующих зонах факела:
G $\genfrac{}{}{0ex}{}{\text{ост.}}{\text{газ}}$ = (0,1-0,0596) м³/с = 0,0404 м³/с
Увеличение отношения d/D > 0,7 нецелесообразно, так как параметр крутки не увеличивается, а сопротивление кольцевого канала растет из-за уменьшения расхода для воздуха (увеличивается диаметр центрального канала при неизменном D). Уменьшение же d/D < 0,45 приводит к уменьшению параметра n < 0,5.In the initial section of the jet, the following amount of gas is burned:

The remaining gas burns in the following zones of the torch:
G $\genfrac{}{}{0ex}{}{\text{rest}}{\text{gas}}$ = (0.1-0.0596) m ³ / s = 0.0404 m ³ / s
An increase in the ratio d / D> 0.7 is impractical, since the twist parameter does not increase, and the resistance of the annular channel increases due to a decrease in air flow (the diameter of the central channel increases with constant D). A decrease in d / D <0.45 leads to a decrease in the parameter n <0.5.

 The optimal range of changes in the ratio of the total area of the outlet openings of the tangentially and radially located gas-distributing tubes is in the range of 0.5 to 1.0. Deviation from the stated ratio leads to a deterioration of the mixture formation and an increase in the content of nitrogen oxides in the combustion products.

As shown by studies conducted on the boiler TGM-84-B (DK 420 t / h), equipped with six burners with rotary gas distribution tubes, the content of nitrogen oxides is 50 70% (100 120 mg / m ³ ).

 Thus, the proposed device for burning gas improves the mixture formation of gaseous fuels with air, which allows to reduce emissions of nitrogen oxides into the atmosphere.

Claims (1)

 A device for burning gaseous fuel, comprising central and peripheral air channels with swirls located in the housing, a collector and rotary gas-distributing tubes mounted on a circumference between the air channels, the outlet openings of the part of the tubes being tangential and the rest radially to the axis of the device, characterized in that a second collector is installed, the ratio of the diameter of the circle on which the gas distribution tubes are located to the inner diameter of the burner body yaet 0.45 0.7, the ratio of the total area of the tangential and radial openings of 0.5 1.0, wherein gazorazdayuschie tube with tangential and radial exit openings are connected to different reservoirs.

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