CN1948832A - Method of using fuel ethanol to instead of power station boiler fuel oil - Google Patents

Abstract

The invention relates to a method for replacing fuel oil in power station boilers with fuel ethanol, which includes completely evaporating, vaporizing and burning fuel ethanol, and evaporating fuel ethanol by self-heating the fuel ethanol, heating the fuel ethanol with the energy released by burning a small amount of fuel ethanol, so that Vaporization of fuel ethanol realizes the self-heating process of fuel ethanol; three steps of oxygen-added combustion and fuel ethanol directly ignite pulverized coal, the advantages of the present invention are: fuel ethanol is used as power plant boiler for ignition and stable combustion, and the combustion-supporting fuel fully meets the needs of power plant boilers, At the same time, it meets the social requirements of energy reduction, and realizes that trace fuel ethanol can directly ignite pulverized coal without an oven.

Description

The Method of Substituting Fuel Ethanol for Fuel Oil of Power Station Boiler

technical field

The invention belongs to a method for replacing fuel oil of a boiler in a power station.

Background technique

At present, with the development of society, my country's fuel oil imports are increasing year by year. Due to the continuous rise of world energy prices, it has seriously restricted the rapid development of my country's national economy. At the same time, people's awareness of energy and environmental protection is increasing, and they choose alternative green Energy fuel will be an inevitable trend.

Power plant boilers have always used light diesel oil as ignition and combustion-supporting fuel, and its combustion performance has been recognized. Since fuel ethanol combustion is usually gaseous combustion, its combustion temperature is much lower than that of light diesel oil, so it is very difficult to burn in liquid state, and there are also certain problems in safe storage and transportation guarantee. At present, the fuel oil consumption of boilers in my country accounts for 30%-40% of the total oil consumption. The raw material for the production of fuel ethanol is biomass, which is a renewable energy source. The CO ₂ and sulfur-containing gases emitted during the combustion of ethanol are lower than the corresponding emissions produced by gasoline combustion, and because its combustion is more complete than ordinary gasoline, its CO emissions can be reduced by about 30%. Therefore, fuel ethanol is called "green energy" or "clean fuel". Moreover, the CO ₂ emitted by fuel ethanol combustion and the CO ₂ consumed by the growth of biomass as raw materials are basically equal in quantity, which is of great significance for reducing air pollution and inhibiting the "greenhouse effect".

When liquid ethanol burns, due to the poor flame length and flame temperature when the liquid is atomized, it will be difficult to ignite and burn unstable when igniting pulverized coal. This has restricted the application of fuel ethanol in power plant boilers in the past.

Contents of the invention

The invention provides a method for replacing fuel oil of a power station boiler with fuel ethanol, so as to solve the problems existing in the current application of fuel ethanol in power station boilers such as difficult ignition and unstable combustion, and at the same time reduce fuel consumption during boiler ignition.

The technical scheme that the present invention takes is, comprises the following steps:

1. Complete vaporization and combustion of fuel ethanol

The self-heating method of fuel ethanol is used to evaporate the fuel ethanol, and the energy released by the combustion of a small amount of fuel ethanol is used to heat the fuel ethanol to vaporize the fuel ethanol to realize the self-heating process of the fuel ethanol.

The fuel ethanol is completely vaporized and combusted through the fuel ethanol burner of the power station boiler. The structure of the power plant boiler fuel ethanol burner is: one end of the combustion chamber is the fuel outlet, and the air distribution chamber with the air distribution port is socketed with the combustion chamber. There is a vent hole at the socket of the combustion chamber and the air distribution chamber. The flow stabilizer is fixedly connected inside the combustion chamber, the other end of the combustion chamber is connected to the pre-combustion chamber, and the serpentine pipe coil is fixedly connected to the pre-combustion chamber. One end of the serpentine pipe coil is connected to the ethanol inlet, and the other end is connected to the ignition nozzle. The ignition nozzle is connected to the pre-combustion chamber, and there is an air distribution port on the pre-combustion chamber; when working, ethanol enters the serpentine pipe ring from the inlet, and the pressure of the ethanol entering is selected: 0.3-0.7Mpa pressure, and the ethanol flow rate is 30kg/h ~200kg/h, the ethanol temperature is room temperature; it is sprayed out through the ignition nozzle, ignited, and partially combusted with a small amount of air, and the ethanol in the serpentine coil is heated in the pre-combustion chamber to vaporize it, and the vaporized ethanol enters the combustion room,

2. Oxygen combustion

After the vaporized ethanol enters the combustion chamber, it is mixed with air or oxygen, and the mixing ratio is ethanol:air=1:9 or ethanol:oxygen=1:4, and is further burned, and finally sprayed out from the fuel outlet and enters the boiler ;

3. Fuel ethanol directly ignites pulverized coal

The main parameters of igniting pulverized coal:

The pulverized coal flow rate of a single burner is 4-6 tons per hour, and the pulverized coal concentration is 0.20-0.60kg/kg;

A wind speed is controlled at 21-24 meters.

In one embodiment of the present invention, air powder inertial separation is used to increase the concentration of pulverized coal in the primary air duct of the boiler, so that the concentration of local pulverized coal in the primary air duct can be concentrated and increased; the flame of the vaporized fuel ethanol is filled with local coal in the primary air duct. In the area of high concentration of coal powder, the trace amount of fuel ethanol has the ability to ignite coal powder.

The invention has the advantages that: the fuel ethanol is completely vaporized and then burned to ensure the homogeneous reaction between the fuel ethanol and oxygen, thereby ensuring sufficient, complete and thorough combustion. Harmful gas emissions are reduced. Oxygen-added combustion technology is used to ensure that the vaporized fuel ethanol has a violent combustion reaction, the temperature increases, and the high-temperature area of combustion appears to expand significantly, which improves the problems of short flame and low ignition temperature that usually occur in ethanol combustion.

Fuel ethanol is used as the ignition and stable combustion of power plant boilers. The combustion-supporting fuel fully meets the needs of power plant boilers. At the same time, it meets the social requirements of energy reduction, and realizes that trace amounts of fuel ethanol can directly ignite pulverized coal without an oven.

Description of drawings

Fig. 1 is a schematic structural view of a power plant boiler fuel ethanol burner according to the present invention.

Fig. 2 is a schematic diagram of igniting pulverized coal by a fuel ethanol burner of a utility boiler.

Detailed ways

Example 1

1. Complete vaporization and combustion of fuel ethanol

The self-heating method of fuel ethanol is used to evaporate the fuel ethanol, and the energy released by the combustion of a small amount of fuel ethanol is used to heat the fuel ethanol to vaporize the fuel ethanol to realize the self-heating process of the fuel ethanol.

The fuel ethanol is completely vaporized and combusted through the fuel ethanol burner of the power station boiler. The structure of the power plant boiler fuel ethanol burner is: one end of the combustion chamber is the fuel outlet, and the air distribution chamber with the air distribution port is socketed with the combustion chamber. There is a vent hole at the socket of the combustion chamber and the air distribution chamber. The flow stabilizer is fixedly connected inside the combustion chamber, the other end of the combustion chamber is connected to the pre-combustion chamber, and the serpentine pipe coil is fixedly connected to the pre-combustion chamber. One end of the serpentine pipe coil is connected to the ethanol inlet, and the other end is connected to the ignition nozzle. The ignition nozzle is connected to the pre-combustion chamber, and there is an air distribution port on the pre-combustion chamber; when working, ethanol enters the serpentine pipe coil from the inlet, and the pressure of the ethanol entering is selected as: 0.3Mpa pressure, ethanol flow rate is 30kg/h, ethanol The temperature is room temperature; it is sprayed out through the ignition nozzle, ignited, and partially combusted with a small amount of air, and the ethanol in the serpentine tube coil is heated in the pre-combustion chamber to vaporize it, and the vaporized ethanol enters the combustion chamber.

2. Oxygen combustion

After the vaporized ethanol enters the combustion chamber, it mixes with oxygen, and the mixing ratio is ethanol:oxygen=1:4 by weight, further burns, and finally sprays out from the fuel outlet and enters the boiler;

3. Fuel ethanol directly ignites pulverized coal

The main parameters of igniting pulverized coal:

The pulverized coal flow rate of a single burner is 4 tons per hour, and the pulverized coal concentration is 0.45kg/kg;

A wind speed is controlled at 21-24 meters.

Use air powder inertial separation to increase the concentration of pulverized coal in the primary air duct of the boiler, and realize the concentration and increase of the local pulverized coal concentration in the primary air duct; the flame after the vaporized fuel ethanol is burned fills the local high concentration area of pulverized coal in the primary air duct, making trace fuel Ethanol has the ability to ignite coal dust.

In this embodiment, after the fuel ethanol burns stably in the vapor state, the visible flame length is between 1.0m-1.5m, and the invisible flame length is 1.5m-2.5m, which is obviously longer than that of liquid ethanol under the same conditions. The visible flame length is 0.5m. m-0.8m. When liquid ethanol burns stably, the highest flame temperature is 1200°C; the flame temperature of ethanol vaporized combustion is higher than that in liquid state. The temperature can reach above 1350°C. The flame cone angle is 50-60(°E) when the gaseous ethanol is burning. The range of high temperature area is large; the temperature change of combustion stability is small. When liquid ethanol is burning, under the condition of stable combustion, the flame cone angle is 20-40(°E), and the range of high temperature area is narrow. Vapor-state ethanol combustion has stable combustion, and there are no bad combustion phenomena such as sparks, no flame wrapping, black smoke, flame interference, snow-shaped sparks, and fire-off. The combustion gas contains no or less harmful gases such as NO _X. The combustion is complete, and the combustion exhaust gas contains no or less combustible gases such as CO or CxHy. Ethanol is uniformly mixed with combustion air in the form of gas before complete combustion, which reduces the latent heat of vaporization required for the vaporization of ethanol after ignition, and its flame temperature is higher than that in liquid state. The temperature can reach above 1350°C. The flame cone angle is 50-60(°E), and the range of high temperature area is large. There is no liquid nucleus in the combustion process of vaporized fuel ethanol, which realizes a homogeneous reaction, ensures sufficient, complete and thorough combustion, and reduces harmful gas emissions.

The flame after the vaporized fuel ethanol burns fills the local high concentration area of coal powder in the primary air duct, so that the trace amount of fuel ethanol has the ability to ignite coal powder. Improving the initial combustion efficiency of pulverized coal combustion is conducive to improving the burnout degree of pulverized coal and reducing the consumption of pulverized coal. After the fuel ethanol burner of the power station boiler is put into use, the cold furnace starts the boiler for no more than 4 hours. The amount of fuel ethanol used for starting is 0.6-0.8 tons, and usually 10-15 tons of diesel oil is required. It can meet the steady combustion effect of the boiler with a load of 30% or less.

After powdering, you can see a bright torch in the fire hole, the torch burns stably, and the torch is generally orange.

Example 2

1. Complete vaporization and combustion of fuel ethanol

The self-heating method of fuel ethanol is used to evaporate the fuel ethanol, and the energy released by the combustion of a small amount of fuel ethanol is used to heat the fuel ethanol to vaporize the fuel ethanol to realize the self-heating process of the fuel ethanol.

The fuel ethanol is completely vaporized and combusted through the fuel ethanol burner of the power station boiler. The structure of the power plant boiler fuel ethanol burner is: one end of the combustion chamber is the fuel outlet, and the air distribution chamber with the air distribution port is socketed with the combustion chamber. There is a vent hole at the socket of the combustion chamber and the air distribution chamber. The flow stabilizer is fixedly connected inside the combustion chamber, the other end of the combustion chamber is connected to the pre-combustion chamber, and the serpentine pipe coil is fixedly connected to the pre-combustion chamber. One end of the serpentine pipe coil is connected to the ethanol inlet, and the other end is connected to the ignition nozzle. The ignition nozzle is connected to the pre-combustion chamber, and there is an air distribution port on the pre-combustion chamber; when working, ethanol enters the serpentine pipe coil from the inlet, and the pressure of the ethanol entering is selected as: 0.5Mpa pressure, ethanol flow rate at 120kg/h, ethanol The temperature is room temperature; it is sprayed out through the ignition nozzle, ignited, and partially combusted with a small amount of air, and the ethanol in the serpentine tube coil is heated in the pre-combustion chamber to vaporize it, and the vaporized ethanol enters the combustion chamber.

2. Oxygen combustion

After the vaporized ethanol enters the combustion chamber, it mixes with air, and the mixing ratio is ethanol:air=1:9 by weight, further burns, and finally sprays out from the fuel outlet and enters the boiler;

3. Fuel ethanol directly ignites pulverized coal

The main parameters of igniting pulverized coal:

The pulverized coal flow rate of a single burner is 5 tons per hour, and the pulverized coal concentration is 0.60kg/kg;

A wind speed is controlled at 21-24 meters.

Use air powder inertial separation to increase the concentration of pulverized coal in the primary air duct of the boiler, and realize the concentration and increase of the local pulverized coal concentration in the primary air duct; the flame after the vaporized fuel ethanol is burned fills the local high concentration area of pulverized coal in the primary air duct, making trace fuel Ethanol has the ability to ignite coal dust.

Example 3

1. Complete vaporization and combustion of fuel ethanol

The self-heating method of fuel ethanol is used to evaporate the fuel ethanol, and the energy released by the combustion of a small amount of fuel ethanol is used to heat the fuel ethanol to vaporize the fuel ethanol to realize the self-heating process of the fuel ethanol.

The fuel ethanol is completely vaporized and combusted through the fuel ethanol burner of the power station boiler. The structure of the power plant boiler fuel ethanol burner is: one end of the combustion chamber is the fuel outlet, and the air distribution chamber with the air distribution port is socketed with the combustion chamber. There is a vent hole at the socket of the combustion chamber and the air distribution chamber. The flow stabilizer is fixedly connected inside the combustion chamber, the other end of the combustion chamber is connected to the pre-combustion chamber, and the serpentine pipe coil is fixedly connected to the pre-combustion chamber. One end of the serpentine pipe coil is connected to the ethanol inlet, and the other end is connected to the ignition nozzle. The ignition nozzle is connected to the pre-combustion chamber, and there is an air distribution port on the pre-combustion chamber; when working, ethanol enters the serpentine pipe ring from the inlet, and the pressure of the ethanol entering is selected as: 0.7Mpa pressure, ethanol flow rate at 200kg/h, ethanol The temperature is room temperature; it is sprayed out through the ignition nozzle, ignited, and partially combusted with a small amount of air, and the ethanol in the serpentine tube coil is heated in the pre-combustion chamber to vaporize it, and the vaporized ethanol enters the combustion chamber.

2. Oxygen combustion

After the vaporized ethanol enters the combustion chamber, it is mixed with air, and the mixture is ethanol: air=1:9 for further combustion by weight and number of parts, and finally it is sprayed out from the fuel outlet and enters the boiler;

3. Fuel ethanol directly ignites pulverized coal

The main parameters of igniting pulverized coal:

The pulverized coal flow rate of a single burner is 6 tons per hour, and the pulverized coal concentration is 0.20kg/kg;

A wind speed is controlled at 21-24 meters.

Claims (2)

1, with the method for fuel ethanol to instead of power station boiler fuel oil, comprises the following steps:

One, the complete carburation by evaporation burning of alcohol fuel,

Adopt the mode of alcohol fuel oneself heating to carry out the evaporation of alcohol fuel,, make the alcohol fuel vaporization, realize the self-heating process of alcohol fuel by the energy heating fuel ethanol that the burning of small amount of fuel ethanol discharges;

Make the complete carburation by evaporation burning of alcohol fuel by station boiler alcohol fuel burner.The structure of this station boiler alcohol fuel burner is: combustion chamber one end is a fuel outlet, distribution plenum and this combustion chamber socket with air distribution outlet, in this combustion chamber and distribution plenum socket place passage is arranged, camber blades formula flow straightener is fixedly connected on inside, combustion chamber, this combustion chamber other end connects precombustion chamber, snakelike pipeloop is fixedly connected in this precombustion chamber, this snakelike pipeloop one end is connected with the ethanol import, the other end is connected with ignition burner, this ignition burner is connected with precombustion chamber, and air distribution outlet is arranged on the precombustion chamber; During work, ethanol enters the snakelike pipeloop from import, and the ethanol pressure that this enters is chosen: be 0.3-0.7Mpa pressure, the ethanol flow is at 30kg/h～200kg/h, and the ethanol temperature is a room temperature; Through the ignition burner ejection, lighted, carry out partial combustion with little air, the ethanol in precombustion chamber in the heating coil circle makes it vaporization, and the ethanol after the vaporization enters the combustion chamber,

Two, oxygenation burning

Ethanol after the vaporization enters behind the combustion chamber and air or oxygen mixes, and mixed is ethanol by ratio of weight and the number of copies: air=1: 9 or ethanol: oxygen=1: 4, and further burning from the fuel outlet ejection, enters boiler at last;

Three, the direct firing coal-dust of alcohol fuel

The major parameter of firing coal-dust:

Single burner pulverized coal flow is by per hour 4～6 tons, and coal powder density is at 0.20～0.60kg/kg;

Primary air velocity is controlled at 21-24 rice.

2, the method with fuel ethanol to instead of power station boiler fuel oil according to claim 1 in step 3, utilizes wind powder inertial separation to improve coal powder density in airduct of boiler, realizes that the interior local coal powder density of airduct obtains concentrating raising; Flame after the alcohol fuel burning after the vaporization is full of the local coal dust area with high mercury of airduct one time, makes micro-alcohol fuel possess the ability of firing coal-dust.