KR20040056876A - Method for combustion of gas-solid two phase fuel in a calcination rotary kiln - Google Patents

Abstract

PURPOSE: A method for firing vapor-phased fuel, cokes oven gas, and solid-phased fuel, cokes powder, in a lime burning kiln is provided to minimize formation of nitrogen oxides(NOx) and loss of energy. CONSTITUTION: The vapor/solid phased fuel in a lime kiln is burned by injecting solid-phased fuel, cokes powder, and air into the center of a burner in a rate of 25-50m/sec, and injecting vapor-phased fuel, cokes oven gas, and air into the sides of a burner in a rate of 10-30m/sec. The cokes powder keeps the temperature inside the kiln homogeneous and the cokes oven gas stabilizes flames. Accordingly, the temperature inside the rotary kiln is controlled by the injection ratio of solid and vapor-phased fuel.

Description

Method for combustion of gas-solid two phase fuel in a calcination rotary kiln}

The present invention relates to a gas-solid mixed combustion method in a rotary kiln for calcining, and more particularly, to a mixed combustion of coke oven gas and solid fuel in the lime kiln. The present invention relates to a method for minimizing the generation of NOx and energy loss.

In the conventional rotary kiln (rotary kiln), the heat source was obtained using a single combustion of the gas and liquid fuel, liquid-solid phase, gas phase-solid phase, gas phase-liquid mixed combustion. However, it was not effective in reducing the uniform heating in the furnace or reducing nitrogen oxides (NOx) in the furnace, aiming only to supply sufficient heat for calcining limestone, rather than using the generated heat effectively.

The present invention was devised to solve the above problems, and a gas-solid mixed combustion method in a rotary kiln for lime firing that can minimize the generation of nitrogen oxides while preventing excessive use of thermal energy. The purpose is to provide.

The gas-solid mixed combustion method in the rotary kiln for lime firing of the present invention for achieving the above object is injected by injecting solid fuel with air at a constant speed in the center of the burner, the gaseous fuel and combustion to the surrounding area Inject the air, and adjust the amount of the combustion air in accordance with the injection amount of the solid fuel and gaseous fuel, the flow rate of the solid fuel is adjusted to 25 ~ 50m / s, the flow rate of the gaseous fuel 10 The injection speed of the solid fuel is always greater than the injection speed of the gas phase fuel.

Hereinafter, a gas-solid mixed combustion method in a rotary kiln for lime firing of the present invention will be described in detail.

In the center of the burner, solid fuel is injected and injected with air at a constant speed, gaseous fuel and combustion air are injected into the peripheral portion, and the amount of combustion air is automatically adjusted according to the injection amount of solid fuel and gaseous fuel. do.

If the total required heat quantity and the flow rate of the solid and gaseous fuel is set in the central operating control panel, the combustion air amount is calculated and set accordingly, and when the first operation is started, the operation is performed at the set value. Once the operation is started, the combustion air volume is adjusted using feedback control to maximize the low temperature, and the fuel flow rate and the air volume for combustion are changed at the same rate so that the low temperature is suitable for calcining at the time when the low temperature is maintained. Do it. In this case, the fuel flow rate is maintained at the first set ratio, and the combustion air amount is additionally repeatedly adjusted so as to be the maximum low temperature as before, so that optimal control is achieved.

In the rotary kiln for lime-calcination, the flow rate of solid fuel is adjusted to 25-50m / s, the flow rate of meteorological fuel is adjusted to 10-30m / s, and the injection speed of solid fuel is always greater than that of meteorological fuel. . Here, the meteorological fuel has a small momentum, and as soon as it is injected into the rotary kiln, the flame length is shortened to an average speed of 2 to 3 m / s, and the solid fuel has its own momentum as well as the injection speed of the meteorological fuel. Because it is always larger, it is sprayed farther while maintaining the injection speed, so that it is separated from the flame of the coke oven gas, which is a gaseous fuel, and the coke oven gas plays a role in stabilizing the flame because the combustion occurs well. The flame length is longer and at the same time radiant heat is generated to maintain the furnace temperature more uniformly, thereby improving thermal efficiency.

At this time, it is possible to adjust the combustion to occur at a lower temperature than when burning in the gas phase alone, it is possible to suppress the generation of nitrogen oxide (NOx) generated during combustion.

In addition, the amount of fuel can be adjusted at the same time to adjust the internal temperature of the rotary kiln according to the injection ratio of the solid fuel and the gaseous fuel, and the fuel consumption can be adjusted to the amount that minimizes fuel consumption. Consumption can be reduced and emissions of pollutants can be reduced.

According to the present invention, it is possible to maintain the best quality of the fired product, to reduce fuel consumption, and to minimize the emission of nitrogen oxides, thereby preventing environmental pollution.

Claims (1)

The solid fuel is injected into the center of the burner with air at a constant speed and injected, the gaseous fuel and combustion air are injected into the peripheral portion, and the amount of the combustion air is adjusted according to the injection amount of the solid fuel and the gaseous fuel. But The flow rate of the solid fuel is adjusted to 25 ~ 50m / s, the flow rate of the gaseous fuel is adjusted to 10 ~ 30m / s, characterized in that the injection speed of the solid fuel is always greater than the injection speed of the gaseous fuel Weather-solid-combustion method in rotary kilns for lime calcination.