JPH0989627A - Bed height measurement method by pressure difference in furnace - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To measure a high level of a bed in a fluidized state. SOLUTION: A large number of furnace pressure measurement holes are provided on the side surface of the furnace body of the waste gasification and melting furnace, and the furnace pressure difference in the furnace height direction is measured,
A method for measuring a flow state by a differential pressure in a furnace in the height direction, characterized in that the signal is processed and the flow state is obtained from the shape of the frequency distribution and the fluctuation of the signal intensity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the bed height level of a waste gasification and melting furnace by means of a differential pressure in the furnace in the height direction.

[0002]

2. Description of the Related Art Conventionally, for example, in a fluidized bed type incinerator, level measurement by differential pressure is performed. This is because the differential pressure in the bed height direction of the fluidized bed in which fuel, such as pulverized coal, which is almost always constant, is made to flow by combustion / fluidizing air is approximately (fluid density) x (bed height). Since it is proportional, it is a method of obtaining the layer height, that is, the level by the differential pressure.

[0003]

However, the above method is effective when the level is stable, but when the quality and level of the fluid change drastically like a gasification and melting furnace, a stable instruction is given. There is a problem that can not be obtained. Therefore, it is an object of the present invention to provide a method for measuring a bed high level in a fluidized state accompanied by a change in fuel quality.

[0004]

The bed height measuring method by means of the in-furnace differential pressure of the present invention comprises a number of holes for measuring the in-furnace pressure provided on the side surface of the furnace body of a waste gasification and melting furnace. It is characterized in that the internal differential pressure is measured, the signal is processed to form a frequency distribution at each measurement point, and the bed height is obtained from the differential pressure distribution having the highest frequency. Further, it is characterized in that the in-furnace pressure difference in the furnace height direction is measured, the signal thereof is processed, and the flow state is obtained from the shape of the frequency distribution and the fluctuation of the signal intensity.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram showing an example of the overall configuration of an apparatus for carrying out the method of the present invention. The waste gasification and melting furnace forms a packed bed of coke, which is a lumpy carbon material, and waste in the furnace body, and supplies high temperature air into the coke packed bed through the main tuyere and the sub-tuyere, The waste that is put into the melting furnace body is gasified and burned to melt the incombustibles. At this time, the upper part of the packed bed is in a fluid state.

A large number of holes for measuring the pressure inside the furnace are provided on the side surface of the furnace body. In this way, the bed height level of the packed bed is obtained by measuring the furnace pressure difference in the furnace height direction. It is desirable that the measurement holes be provided at several places from the freeboard section to the sub-tuyere fixed layer section.

FIG. 2 (a) shows an example of the measurement result of the pressure difference between each part of the height direction and the atmosphere. The horizontal axis is the height from the sub tuyere, the left side shows the fixed bed, the middle part to the right side shows the fluidized bed, and the right end shows the freeboard part.

However, the signals are extremely varied, and it is difficult to judge the layer height if the signals remain as they are. Therefore, this signal is processed to display the level with the highest frequency distribution at each measurement point in (b). If the layer height is defined as the height (layer surface) at which the pressure difference becomes zero, it can be easily identified from this figure. In this way, the signal processing enables clear and stable determination of the layer height.

FIG. 3 schematically shows the relationship between the frequency distribution of the measurement signal, the signal intensity and the flow state in the furnace. (A)
Indicates that the frequency distribution is a sharp mountain shape, the signal strength is high, and the flow state is weak. (C)
Indicates that the frequency distribution has a flat mountain shape and the signal intensity is weak, indicating that the flow state is strong. In addition, the frequency distribution and the signal strength of (b) are the same as (a) and (c) above.
In the middle of the, the flow state also shows an intermediate state between the two.

[0010] These relationships change somewhat depending on the particle size distribution of the furnace interior charge, but the flow state can be grasped from the distribution shape. In addition, the temperature inside the furnace also changes depending on the flow state.
As shown in (c), the fact that the flow is heavy means that the amount of air blown to the auxiliary tuyere is usually large, and the amount of heat taken out by the gas is large, so that the temperature inside the furnace tends to decrease. On the other hand, FIG.
On the contrary, in the case of (a), the temperature inside the furnace tends to rise.

Therefore, by comparing the distribution shape with the temperature in the furnace, the situation in the furnace can be grasped more accurately. In these cases, as shown in Table 1, the pressure difference between the freeboard portion and the fluidized portion may be determined to measure the bed height. On the other hand, for the measurement of the flow state, (b) the differential pressure between the freeboard portion and the fluid portion, (c) the differential pressure between the fluid portion and the fixed portion may be used, but the optimum one is the freeboard portion as shown in (a). It is desirable to measure the pressure at the flow part and the fixed part and judge by the pressure difference between these three.

[0012]

[Table 1] FIG. 4 is an example of application of the present invention to the operation. As a result of incorporating the method of the present invention from 12 hours after the start of operation, the result was that the temperature in the furnace had been dependent on the furnace temperature until now, resulting in wandering. As for the operation, stable operation can be performed by charging so that the bed height is kept constant.

[0013]

EFFECTS OF THE INVENTION It has become possible to stably measure a high level of a bed in a fluidized state.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of the overall configuration of an apparatus for carrying out the method of the present invention.

FIG. 2 is an explanatory diagram of an example of measurement results.

FIG. 3 is an explanatory view schematically showing the relationship between the frequency distribution of measurement signals and the in-furnace flow state and in-reactor temperature.

FIG. 4 is an explanatory diagram of the operation history.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tomohiro Yoshida 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Inventor Yasuo Suzuki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Date Main Steel Pipe Co., Ltd.

Claims (2)

[Claims] 1. A number of holes for measuring the pressure inside the furnace are provided on the side surface of the furnace of the waste gasification and melting furnace, the differential pressure inside the furnace in the height direction is measured, the signal is processed, and the frequency is measured at each measurement point. A method for measuring bed height by in-reactor pressure difference, characterized in that the bed height is calculated from the most frequent differential pressure distribution. 2. A number of holes for measuring the pressure inside the furnace are provided on the side of the furnace body of the waste gasification and melting furnace, the pressure difference inside the furnace in the height direction is measured, the signal is processed, and the frequency distribution shape is measured. And a method for measuring a fluidized state by means of a differential pressure in a furnace, characterized in that the fluidized state is obtained by a change in signal intensity.