SU567894A1 - Fuel combustion method - Google Patents

Description

. The invention relates to methods for burning fuel, mainly fine solid, in industrial and energy steam boilers and can be used in heat and power engineering and some other related areas of technology.

The known method of low-temperature combustion of finely dispersed solid fuel with simultaneous cooling and purification of flue gases from harmful components by adding chemical reagents to the fuel, such as limestone, at KSUGOR, fuel is burned at the points of the fluidized bed with immersed heat exchange surfaces in the layer. fuel combustion reduces the firebox’s habardt and at the same time reduces environmental pollution by harmful components, for example, nitrogen (due to lower temperatures burning grades up to 700-1000), sulfurous anhydride, etc.

The disadvantages of this method are the large hydrodynamic resistance of the fluidized bed, limited in intensity.

the nature of the combustion and heat transfer processes associated with the entrainment of dispersed particles from the bed, as well as the difficulty of evenly distributing the fuel in the bed.

Methods for burning fuel are also known. in a suspended state, by supplying an air-fuel mixture by counter-impacting jets with simultaneous heat removal by means of a cooling fluid circulating in pipes 2.

However, in these methods, the processes of combustion and heat removal are not sufficiently effective due to the insignificant turbulization of the flows B in the impact zone.

The purpose of the invention is to intensify the combustion process during the low-temperature combustion mode while simultaneously cleaning the flue gases from harmful impurities.

This is achieved in that the jets are pulsed with a pulsation frequency of 5-10 Hz, and the heat is removed in the impact zone when the tubes are placed perpendicular to the flows of the colliding jets. The way is. that the combustion of fuel at tj.Qp 1OOO C (finely dispersed, gaseous, liquid) is carried out in the counter-flow of air during simultaneous heat exchange with heating surfaces located in the impact zone (through which cooling fluid circulates) under pulsed mode of the fuel-air mixture. Simultaneously with the corrugation and heat exchange, flue gases are cleaned from harmful components, for example SO, by adding fuel to the corresponding reagents (lime and so on.

To further intensify the combustion and heat exchange processes, the collision zone is turbulized by lateral placement of the tubular heat exchange surfaces. The frequency of the pulsation of the air-fuel mixture under a pulsed feed mode is assumed based on the condition that the flow collisions do not extend beyond the tubular heat exchange surface. With the limits of variation of the amplitude of gas velocities of 5-5 O m / s, which are practically realized in steam boilers and with a length of the heat exchange zone of 1-5 m, the frequency of pulsations lies within 0.5-10 Hz. The transversely washed tubular heat exchange surface, placed in the zone of impact of the air-fuel flows in the corridor or staggered order, simultaneously plays the role of a turbulizing grate for collisions of two-phase flows.

The pulsed mode of supplying the fuel-air mixture leads to a continuous renewal of the gas layer near the fuel particles near the pipe walls and in the feed zone and does not allow the stationary boundary layer to develop, which inhibits the heat and heat exchange processes.

Intensive mixing of fuel with air, oscillatory motion of fuel particles in the zone of collision of flows, turbulization of two-phase flows in a tube sheet and hydrodynamic non-stationarity, realized at. The proposed method of fuel combustion significantly intensifies both the combustion process and the heat exchange and reduces the size of the furnace and convective surfaces of the boiler.

FIG. 1 precalculate installation scheme in which the proposed method of burning fuel is implemented; in fig. 2-- cut. A-A of FIG. one.

The installation is mainly intended for burning fine solid fuel and contains channels 1 for supplying the fuel-air mixture to the furnace, channels 2 for supplying secondary air, prechamber 3, channels 4 for connecting pre-chamber 3, main furnace 5, pipes 6,

located in the furnace 5, pulsator valves 7 installed in channels 1 to 2, servomotors 8, command devices E, outlet channels Y.

The installation works as follows.

Channels 1 and 2 B pre-chamber sub. The fuel-air mixture is heated and the secondary air is heated. From the pre-chambers 3 through channels 4 a mixture of fuel and air is supplied to the furnace 5, in which are located the cooling pipes 6, which serve simultaneously as heating surfaces of the steam boiler, are located along the river E direction. Pipes 6 can be located both in chess and corridor order.

Combustion of fuel occurs in the annular space during the collision of the fuel-free air. flows. The supply of the air-fuel mixture is carried out in a pulsed mode, achieved with the help of the pulsating valves 7 installed in channels 1 and 2. The pulsating valves 7 are driven by servomotors 8 controlled by command devices 9.

The cooled gases from the combustion zone are discharged through the channels Yu and then enter the convective and tail heating surfaces of the boiler (not shown). Behind the steam boiler, dust collectors of one or another construction are installed, for example, cyclones separating ash particles and a cleansing additive from gases. The cooled purified gases are discharged to the atmosphere.

The efficiency of the proposed fuel combustion method is determined by the high intensity of heat exchange processes in the combustion zone, a decrease in aerodynamic resistance, megalloemkostok and dimensions, a decrease in heat loss from the inconvenience to the environment, and a decrease in environmental pollution

Claims (2)

Invention Formula The method of burning fuel, predominantly solid, fine, in a suspended state, by supplying an air-fuel mixture by counter-impacting jets with simultaneous heat removal from the coolant circulating in the tubes, is characterized in that, in order to intensify the process of burning, birth horopin and simultaneous cleaning of flue I-H3OB GG harmful impurities, the scab is fed, spmi with a purity of pul1 of spacia 5-1O H, the fuel removal is carried out in the area of the vessel, with pfi.-w displacement of the pipes perpendicular to the collision flows. jets. Sources of information taken into account in the examination: 1. V. Dobrokhotov. Essential directions in the development of boiler equipment for the near future Teploenerg-erkka 1975, No. 9, p. 3-4. 2. Copyright certificate № 486185, - 23 C 1/10. 1971. Fig. / at W