JPS5885136A - Device for measuring concentration of carbon monoxide gas in gas including coal dust - Google Patents

Abstract

PURPOSE:To measure the concentration of the carbon monoxide gas accurately and stably by providing a porous member at a part for introducing the carbon monoxide gas at the outside of a container wherein the measuring device is provided. CONSTITUTION:The measuring device comprises the container 7 having an attaching flange 6, the porous member 8 which is attached to said container 7, a detecting part 9 for measuring gas concentration arranged in the container 7, a pressure adjusting device 10, and the like. A pressure adjusting chamber 13 having a gap of about 1mm. between a back surface 11 of the porous member and a front surface 12 of the detecting part is formed. A material, which is formed by sintering metal powder in a plate shape, is used as the porous member 8. The diameter of the small hole is determined in correspondence with the distribution of the sizes of the particles of the fine coal in the fluid flowing in an outlet duct 4. In this constitution, the concentration of the carbon monoxide in the fluid including a large amount of the coal dust and moisture can be measured accurately and stably.

Description

DETAILED DESCRIPTION OF THE INVENTION A device for measuring the concentration of carbon monoxide in a fluid flowing through a supply system of pulverized coal for combustion, a combustion exhaust gas system, etc., which contains a large amount of water, especially a porous material (7) The present invention relates to a simple device for measuring the concentration of carbon monoxide gas in waste containing coal dust, which does not cause clogging of the measuring device.

Recently, the use of coal-fired boilers in thermal power plants has been increasing from the perspective of saving oil resources, and the combustion equipment of these boilers includes pulverized coal mills that pulverize the coal to burn it efficiently. Widely used. However, due to the lack of suitable measuring equipment, the combustible scum, mainly carbon monoxide gas, generated inside the pulverized coal mill can cause an explosion. Hereinafter, a conventionally used carbon monoxide concentration measuring device and its problems will be described.

Figure 1 shows an apparatus for measuring the concentration of carbon monoxide in a fluid that does not contain dust or moisture. This device is equipped with a container (b) having an opening on the side wall of a tact (a), a slit (c) at the entrance of the opening, and a measuring device (d) inside the container (b).
) are arranged. Carbon monoxide residue in the fluid flowing in the direction of arrow e in the duct (α) passes through Surin h (c) and enters the container (b), where the gas concentration is measured, but the situation changes and dust particles are present in the fluid. When the water content increases, the slit (c) becomes blocked and measurement becomes impossible.

FIG. 2 shows the measuring device when there is relatively little dust and moisture. This device is equipped with a sampling port (force) on the side wall of the tact (a), and as shown in the figure, a measuring device (d ).This device is installed at a pulverized coal concentration of approximately 0.8.
When installed in the outlet duct of a pulverized coal mill of 97m
Occurrence of occlusion in 0 seconds.

Figure 5 shows an improved version of Figure 2, with filter (g)
A heater (3) and a cooler (k) are provided on the inlet side of the fluid to remove moisture from the fluid. This type of filter is also free from clogging of the filter medium, but it also has the disadvantage that carbon monoxide carbon 4 is newly generated during the heating process, which hinders accurate measurement.

The present invention eliminates the above-mentioned drawbacks, allows accurate measurement of the concentration of carbon monoxide residue in waste containing a large amount of dust and a considerable amount of water, and is simple and does not cause clogging of the measuring device. It was developed for the purpose of providing a device for measuring the concentration of carbon monoxide gas in waste containing coal dust.
This is a carbon monoxide scum a# measurement device that receives carbon monoxide scum and measures the scum concentration, and is equipped with a porous member at the part where carbon monoxide scum from outside the container is introduced.

Embodiments of the present invention will be described below based on the drawings.

In Figures 4 to 7, code (1) is a pulverized coal mill;
(2) is coal input (loading in the direction of arrow m), (3)
is the air and water vapor supply pipe (inflow from the direction of arrow n), (
, +1 is the exit tact, -carbon oxide scum concentration 41
11 Remove the measuring device (hereinafter referred to as measuring device) (5).
- Attach to the side wall of (4). The coal pulverized by the pulverized coal mill (1) is discharged by pressurization or depressurization.
- The air flow flowing upward inside (4) - arrow p
The coal flows in the direction of , and is transported to the boiler combustion section or coal storage section.

Note that the pressure in the exit tact varies depending on the position of the fan and the transportation distance, but is approximately several hundred mm of water column.

As shown in FIG. 7, the measuring device (5) consists of a container (7) having a mounting flange (6), a porous member (8) attached to the inlet of the container (7), and an inner surface of the container (7). Detection unit (9) and pressure regulator (10) for gas concentration measurement located in
etc., the rear surface of the porous member) and the front surface 02 of the detection part.
) forms a pressure adjustment chamber (13) having a gap of approximately one journey. The pressure adjustment chamber (13) also includes a communication pipe (14) that connects to the pressure regulator θ0) and a waste discharge pipe (15).
), and each of the 6 pipes α4)0 and 06) has a valve 06)θη
Install.

The porous member (8) is made of metal powder sintered into a plate shape, and the average pore diameter is determined in accordance with the particle size distribution of pulverized coal in the fluid flowing inside the outlet duct (4). The particle size distribution from a pulverized coal mill of about 200 mesh is shown in Figures 8 and 9.
As shown in the figure, in particular, as shown in FIG. 8, the ratio of particles having a particle size of 2 μm or more to the total is about 93%, so it is preferable to set the average pore diameter to 2 μm. Furthermore, the 8th
In the graph in the figure, the number shown on the horizontal axis, for example 2 μm, indicates the cumulative total of all particles larger than 2 μm, and the number shown on the vertical axis, for example 93%, indicates the cumulative total of all particles larger than 2 μm. Shows the percentage of The metal powder sintered plate has high wear resistance against pulverized coal, so it can withstand long-term use. Note that a porous member having air permeability such as ceramic synthetic resin may be used instead of the metal powder sintered plate.

The detection unit (9) for measuring the dregs concentration uses a semiconductor sensor for -carbon oxide gas. This sensor has a detection part (9
) is based on the principle that the electrical conductivity changes when carbon monoxide gas is adsorbed on the surface of the sensor.The change in the signal current generated by the sensor is taken out to the outside via the wire 1' (18j) and displayed on a display (not shown). Display the measured value. Use a commercially available semiconductor sensor.

The pressure regulator (10) equalizes the fluid pressure inside the outlet tact (4) and the pressure inside the pressure adjustment chamber (13), and also controls the ventilation inside the pressure adjustment chamber (13) and the reverse of the porous member (8). Use for washing.

Next, the operation of this device will be explained. First, the pressure adjustment chamber (
13) After releasing the scum inside and ventilating, open the valve (16).
) (17) close. Next, the pressure in the pressure adjustment chamber 03) and the pressure of the fluid in the outlet tact (4) are equalized.

Therefore, no gas flow occurs due to the pressure difference, and the carbon monoxide residue in the outlet duct (4) is completely diffused (the gas molecular components move from the high concentration area to the low concentration area [-1 Eventually, the entire area (This is a phenomenon in which the concentration difference depending on the location disappears) and the gas concentration enters the container (7).
9) and measurement is performed. At this time, even if sudden pressure fluctuations occur accidentally and fluid flows from the inside of the outlet duct into the pressure adjustment chamber, the pulverized coal is removed by the porous member (8), so the pulverized coal enters the container (7). There is no fear. Note that by backwashing fine dust that has entered the porous member (8), the function of the porous member can be restored, so stable measurements can be continued for a long period of time.

Note that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

The device for measuring carbon monoxide gas concentration in gas containing coal dust according to the present invention has the above-described configuration and exhibits the following excellent effects.

(1) The concentration of carbon monoxide scum that has passed through a porous member due to diffusion is directly measured, without the need to filter a fluid containing dust and moisture or install a moisture removal device, which was the case in the past. , no clogging occurs in the porous member.

Therefore, the concentration of carbon monoxide residue in a fluid containing a large amount of dust and moisture can be measured accurately and stably.

(11) The measuring device is composed of a container in which the measuring device is placed, a porous member interposed between the measuring device and the fluid to be measured, so the structure is extremely simple and the measurement operation is is simple.

By providing a pressure adjustment chamber between the porous member and the detection section, it is possible to prevent fine dust from entering the porous member, so that measurement can be continued for a long period of time.

oXA By connecting the measuring device of the present invention to an alarm device, it is possible to prevent an explosion accident of -carbon oxide gas.

[Brief explanation of drawings]

1 to 3 are explanatory diagrams showing an outline of a conventional carbon monoxide gas concentration measuring device, and FIG. 4 is a layout diagram showing the installation position of a carbon monoxide gas concentration measuring device according to an embodiment of the present invention. FIG. 5 is a partially enlarged perspective view of the measuring device shown in FIG. 4, and FIG.
The figure is a partially cutaway side view of Fig. 5, Fig. 7 is a partially enlarged side view of Fig. 6, and Fig. 8 is a particle size distribution diagram showing the proportion of particles of each diameter or more in the total of pulverized coal. FIG. 9 is a particle size distribution diagram showing the proportion of particles of each diameter of pulverized coal to the total. In the figure, (1) is the pulverized coal mill, (4) is the output rotary tank l-1 (
7) is a container, (8) is a porous member, and (9) is a detection part. Patent applicant Ishikawajima Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1) In a carbon monoxide gas concentration measuring device that receives carbon monoxide into a container containing a measuring device and measures the gas concentration, a porous member is provided at the part where carbon monoxide gas outside the container is introduced. A device for measuring carbon monoxide gas concentration in gas containing coal dust, characterized by: