RU2118750C1 - Method of burning liquid fuel - Google Patents

Abstract

FIELD: burning liquid fuel in furnaces of boilers and thermoelectric plants. SUBSTANCE: liquid fuel is preheated in course of swirling it in cylindrical layer by tangential flows of hot gaseous agent followed by passing these flows through layer of revolving fuel from periphery of layer towards axis of its rotation. Spraying and injection of mixture of fuel and hot agent into boiler furnace will be effected due to delivery of high-velocity air flow through inner cavity of cylindrical layer of fuel and hot agent mixture. High-velocity air flow is swirled in direction opposite to direction of rotation of circular layer of fuel and hot agent mixture; this flow is subjected to additional heating. Liquid fuel is simultaneously preheated due to delivery of tangential flows of hot gaseous agent together return of priming followed by passing their mixture through circular layer of revolving fuel. Besides that, atomization of fuel and hot agent mixture is effected due to delivery of high-velocity air flow together with return of priming. EFFECT: enhanced stability of combustion; reduction of unburned carbon and incomplete combustion. 5 cl, 1 dwg

Description

 The invention relates to methods for burning liquid fuel, mainly water-coal fuel, carried out in boiler plants.

 The invention can be used in heat and power.

 Known methods of burning liquid fuel, carried out by spraying it in steam-mechanical and pneumomechanical nozzles and subsequent injection of the atomized mixture of fuel and oxidizer into the boiler furnace [1].

 The closest solution is a method of burning liquid fuel, mainly water-coal fuel, according to which the flow of water-coal suspension is swirled with primary air in a conical nozzle, and the fuel is sprayed by supplying secondary air from the periphery of the nozzle at the place of its exit to the boiler furnace [2].

 The disadvantages of these methods are: low atomization efficiency of heavy liquid fuels, especially water-coal fuels, which leads to increased losses with mechanical and chemical burnout of fuel; low reliability of the devices for spraying and supplying atomized fuel into the furnace furnace space due to the possibility of clogging of nozzles with solid particles; high costs of thermal energy for fuel heating.

 The objective of the invention is to remedy these disadvantages, as well as increasing the stability of combustion and reducing the mechanical and chemical burnout of fuel.

 To achieve this objective, the heating of liquid fuel is carried out in the process of twisting it into a cylindrical layer by tangential flows of a hot gaseous agent and then passing the latter through a layer of rotating fuel from the periphery of the layer to the axis of rotation, and spraying and injecting a mixture of fuel and hot agent into the boiler furnace due to the supply of a high-speed air flow through the inner cavity of the cylindrical layer of the mixture of fuel and hot agent. In addition, the high-speed air flow is heated and swirl in the opposite direction to the rotation direction of the annular layer of the mixture of fuel and hot agent, and the heating of liquid fuel is carried out by supplying tangential flows of the hot gaseous agent together with the return of entrainment and subsequent passage of their mixture through the annular layer of rotating fuel. In addition, the spray of the mixture of fuel and hot agent is carried out by supplying a high-speed air stream in conjunction with the return of entrainment.

 Thus, the new distinguishing features in the method are: the heating of liquid fuel is carried out in the process of twisting it into a cylindrical annular layer by tangential flows of a hot gaseous agent and then passing them through a layer of rotating fuel from the periphery of the layer to the axis of rotation; spraying and blowing the mixture of fuel and hot agent into the furnace of the boiler is carried out by supplying a high-speed stream of air through the inner cavity of the cylindrical layer of the mixture of fuel and hot agent; a high-speed air flow is twisted in the opposite direction to the rotation direction of the annular layer of the mixture of fuel and hot agent; additionally carry out heating of a high-speed air flow; the heating of liquid fuel is carried out in the process of supplying tangential flows of a hot gaseous agent together with the return of entrainment and the subsequent passage of their mixture through a cylindrical layer of rotating fuel; the mixture of fuel and hot agent is sprayed by supplying a high-speed air stream in conjunction with the return of ablation.

 The organization of the swirling annular layer and the passage of hot air through it ensures effective heating of the water-carbon suspension due to the uniform penetration of the gaseous agent through the fuel layer from the periphery to the axis of its rotation and the formation of a homogenized rotating fuel-air mixture due to this hollow cylindrical layer. The simultaneous supply of a high-speed air stream through the inner cavity of the annular layer of a homogenized mixture of fuel and a hot gaseous agent ensures the disruption of the particles of the fuel mixture, their effective atomization and injection of atomized fuel into the boiler furnace. The required ratio of fuel to air is easily controlled by supplying fuel to the rotating layer by supplying a peripheral hot gaseous agent and a central air stream.

To increase the efficiency of homogenized fuel atomization, the axial high-speed air flow is twisted in the direction opposite to the direction of rotation of the annular layer. At the same time, to improve ignition and reduce fur and chemical burns, a high-speed axial air flow is additionally heated. To reduce the mechanical burn and increase the heating efficiency of the fuel, together with the tangential peripheral flows of the hot gaseous agent, the entrainment return is passed through the fuel layer - unburned coal particles trapped in the first degree of flue gas purification. Their temperature, as a rule, is 300-350 ^o C, the yield of volatiles is 3-5%, and the ash content is 35-35%.

 In another embodiment, the ablation return is supplied in conjunction with an axial high-speed air flow. In this case, the same goal is achieved; the efficiency of fuel heating and the reduction of fur and chemical burns are increased.

 In FIG. 1 shows a diagram of a device for implementing the proposal of a method for burning liquid fuel, mainly water-coal fuel.

 Through the tangential pipe 1, coal-water fuel (VUT) enters the receiving chamber 2 of the burner body 3. Guide vanes 4 are installed in the burner body to ensure uniform distribution of the tangential flows of the hot gaseous agent entering through the tangential nozzles 5.

 The tangential flows of the hot gaseous agent twist the liquid fuel entering the burner body, heating and homogenizing it as a result of direct contact when the rotating layer of fuel penetrates from the periphery to the center of the inner surface of rotation.

 At the same time, the axial air flow entering the burner body through the nozzle 6 is fed through the internal cavity of the rotating fuel layer at a high speed. This high-speed flow disrupts the homogenized and heated fuel particles by spraying them and carries the resulting air-fuel mixture into the boiler furnace. This ensures efficient ignition and complete combustion of fuel. To twist the axial air flow in the nozzle 6 installed guide vanes 7.

 Achievement of the task is confirmed by an example of the implementation of the proposed method, carried out on one (Art. No. 4) of two boilers KVTS-20, converted to burning water-coal fuel, in the boiler room of the Inskaya mine, located on the site of the head structures of the Belovo-Novosibirsk coal pipeline. The flow chart of boiler piping is shown in FIG. 2. Each of the two KVTS-20 boilers is equipped with four windows located in the side walls of the boiler. Each window of the boiler N 4 is equipped with a burner made for the implementation of the combustion of coal-water fuel according to the proposed method. In the table. 1 presents the technical characteristics of the boiler KVTS-20 and one burner.

 The results of the boiler are presented in table. 2.

 As can be seen from the table. 2, the implementation of the proposed method for burning coal-water fuel allowed to increase the efficiency of combustion from 78.8 to 85.6% with a decrease in smoke more than 3 times and a decrease in nitrogen oxides more than 1.6 times. At the same time, the stable operation of the boiler was established with its full transfer to the combustion of coal-water fuel.

 In the spring-summer period of 1998, it is planned to convert the second boiler (see N 3) in the boiler room to the proposed method for burning water-coal fuel.

Claims (5)

 1. A method of burning liquid fuel, mainly water-coal fuel, including heating and spraying fuel, supplying atomized fuel to the furnace of the boiler, feeding return of ablation to the furnace of the boiler, characterized in that the heating of liquid fuel is carried out in the process of twisting it into the cylindrical layer by tangential flows of hot gaseous agent and then passing the latter through a layer of rotating fuel from the periphery of the layer to the axis of rotation, and spraying and injecting a mixture of fuel and hot agent into the boiler furnace due to the supply of a high-speed air flow through the inner cavity of the cylindrical layer of the mixture of fuel and hot agent.  2. The method according to claim 1, characterized in that the high-speed air flow swirl in the opposite direction to the direction of rotation of the annular layer of the mixture of fuel and hot agent.  3. The method according to PP.1 and 2, characterized in that it additionally carry out the heating of a high-speed air flow.  4. The method according to claims 1 to 3, characterized in that the heating of liquid fuel is carried out by supplying tangential flows of a hot gaseous agent together with the return of entrainment and the subsequent passage of their mixture through an annular layer of rotating fuel.  5. The method according to claims 1 to 3, characterized in that the spray of the mixture of fuel and hot agent is carried out by supplying a high-speed air stream together with return of ablation.

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