JPH05322718A - Measuring device for ash uncombusted portion in boiler exhaust gas and operating method for measuring device - Google Patents

Abstract

PURPOSE:To provide a measuring device for the ash uncombusted portion in a boiler exhaust gas and an operating method for it which enhances the reliability of a flue gas sample and blocking of the sampling probe of an ash uncombusted portion gauge by increasing the flue gas sampling response speed using a simple configuration. CONSTITUTION:This device comprises a bypass line 7 consists of a fan 12 and a piping leading to a flue gas return part situated downstream in the flue gas stream from a flue gas suction part via a flue gas sampling part; as well as a flue gas suction part consisting of a flue gas branching nozzle or nozzles 8 having a suction hole or holes 10. Furthermore this device is provided with an ash uncombusted portion gauge 5 to sample the flue gas through a sampling probe 6 out of the bypass line 7 and an intra-piping flue gas heating device 13 equipped with a temp. control device 11 furnished on the bypass line 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ash in flue gas of a boiler such as pulverized coal burning using an unburned ash continuous analyzer (hereinafter simply referred to as ash unburned content meter). TECHNICAL FIELD The present invention relates to a measuring device and an operating method thereof for the purpose of improving a flue gas sampling response speed, preventing clogging of an ash unburned gas meter sampling probe, and improving flue gas sample reliability in an unburned gas measuring system.

[0002]

2. Description of the Related Art FIGS. 4 to 5 are views showing a conventional technique.
Is a diagram showing the position of the flue gas sampling unit in the boiler, and FIG. 5 is a partially enlarged view showing the configuration of the flue gas sampling unit in FIG. 4 to 5, 51 is a furnace, 52 is a second flue, 53 is an air preheater, 54 is a flue gas sampling unit, 55 is a sampling probe, 56
Is an unburned ash content meter, 57 is a measuring unit, and 58 is a vacuum pump.

In the conventional technique, the unburned ash content is measured by vacuum pumping the flue gas from a sampling probe 55 having a nominal diameter of about 10 mm which is inserted into the second flue 52 of the boiler body as shown in FIG. 58, and the unburned ash content meter (Japanese Patent Laid-Open No. 62-217143, Japanese Patent Laid-Open No. 2-1
Those described in Japanese Patent No. 30453. ) 56 measuring unit 5
In No. 7, the unburned content in the ash of the fly ash in the flue gas is measured.

[0004]

As described above, also in the above-mentioned conventional technique, it is possible to suck the flue gas from the flue of the boiler and measure the unburned ash content in the gas. However, when installing the unburned ash content meter 56,
The location of the flue is limited due to restrictions such as the layout of the flue or the installation standard on the ash unburnt carbon meter 56 side, and the length of the sampling probe 55 is accordingly lengthened, so that the sampling response time is increased and the flue is also increased. Since the gas is intermittently sucked, fly ash settles in the sampling probe 55 when the flue gas suction is stopped, and the sampling probe 55 is likely to be clogged.

Further, since the nominal diameter of the sampling probe 55 is as small as about 10 mm, when gas sampling is performed from a flue having a cross-sectional area of several square meters or more, the number of sampling points is essentially one. As a result, it was an inadequate flue gas sampling method.

The present invention has been made in view of the above circumstances, and improves the flue gas sampling response speed with a simple structure and low cost, prevents clogging of the ash unburned carbon content sampling probe, and smoke. It is an object of the present invention to provide a device for measuring unburned ash in flue gas and an operating method thereof, which can improve the reliability of gas sample.

[0007]

The above-mentioned object can be achieved by a measuring device and an operating method thereof for measuring unburned content in ash in a boiler exhaust gas described in the claims. That is, in a system for continuously analyzing unburned ash in fly ash in flue gas of a boiler such as pulverized coal burning, using a continuous analyzer for unburned ash, at least one or more suction holes are provided. It consists of a flue gas suction part consisting of the above flue gas branch nozzles, a pipe and a fan from the flue gas suction part to the flue gas return part on the downstream side of the flue gas flow through the flue gas sampling part. A bypass line, an in-pipe flue gas heating device equipped with a temperature control device attached to the bypass line, and an ash unburned gas meter for collecting flue gas from the bypass line through a sampling probe. An instrument for measuring unburned ash content in boiler exhaust gas.

[0008] The apparatus for measuring unburned ash in flue gas of a boiler according to the above description, wherein the piping of the bypass line is formed in a downward flow including a downward direction. After heating the temperature of the flue gas in the bypass line above the dew point of the gas by the heating device, start the fan that constitutes the bypass line, sufficiently replace the flue gas in the bypass line with air, and then heat the fan and heating. A method for operating a measuring device for stopping the device or measuring the unburned ash content in boiler exhaust gas. Is. Hereinafter, the operation and the like of the present invention will be described based on Examples.

[0009]

1 to 3 are views showing an embodiment based on the present invention, FIG. 1 is a view showing a constitution of a measuring device of unburned ash content in boiler exhaust gas according to claim 1, and FIG. The figure which shows the mounting position of the measuring device of the unburned-gas content in the ash in the boiler exhaust gas according to Item 2, and FIG. 3 is a partially enlarged view showing the configuration of the measuring device for the unburned-content in the ash of the boiler exhaust gas in FIG. In FIGS. 1 to 3, 1 is a furnace, 2 is a second flue, 3 is an air preheater, 4 is a flue gas denitration device, 5 is an unburned carbon content meter in ash, 6 is a sampling probe, 7 is a bypass line, 8 Is a flue gas branching nozzle, 9 is a flue gas return nozzle, 10 is a suction hole, 11 is a temperature control device, 12 is a fan, 13 is a heating device, and 14 is a measurement position of unburned ash in boiler exhaust gas. ..

First, in FIG. 1, a part of the flue gas flowing in the second flue gas is branched by a flue gas branching nozzle 8 having a plurality of suction holes 10, and a fan 12 applies a required pressure to the flue gas. A bypass line 7 is again configured to feed the flue gas into the second flue 2 through the gas return nozzle 9.

The unburned ash content meter 5 is installed as close to the bypass line 7 as possible, and the sampling probe 6 is placed in the bypass line 7 located at a shortest distance from the unburned ash content meter 5 for a necessary and sufficient length. Is inserted, and a required flue gas sample is sucked into the unburned carbon content meter 5 in ash to measure the unburned gas content.

The bypass line 7 is branched from the second flue 2.
The flue gas flowing through the ash is passed through the flue gas sample extracting unit of the ash unburnt gas meter 5 to the required pressure by the fan 12 and then flue gas returning nozzle 9 to smoke again into the second flue 2. Flue gas is sent to the flue, but at that time, select a location that does not affect the flue gas properties and flow state at the branch point, and the flue provided downstream of the flue gas flow from the flue gas suction unit. It is returned from the gas return section into the flue. The flue gas is continuously circulated in the bypass line 7 at a sufficient flow rate regardless of whether the flue gas in the ash unburned gas meter 5 is being sucked or is not in operation.

2 to 3, the bypass line 7 is formed so as to have a downward flow, and the position of the return nozzle 9 of the flue gas return section is located downstream of the flue gas flow section than the flue gas suction section. It is provided on the side. Since the bypass line 7 is always formed downward, the flow of the flue gas in the bypass line 7 can be stabilized, and the position of the flue gas suction portion of the bypass line 7 can be set to be greater than that of the flue gas return portion. When a certain pressure loss is expected between the suction part and the return part, which is provided on the upstream side of the flue gas flow, the fan 12 forming the bypass line 7 described in FIG.
Can reduce its capacity, and in particular, the flue gas denitration device 4 is interposed between the flue gas suction part and the flue gas return part as shown in FIGS. In that case, it is possible to omit the fan 12 completely.

When measuring the unburned ash content in the ash in the boiler exhaust gas based on the present invention,
Follow the procedure below. Flue gas generally contains around 10% of water depending on the charcoal used,
For this reason, when the gas temperature in the bypass line 7 falls below the dew point, dew condensation occurs, and fly ash in the gas may be slurried and adhere to the inner wall of the pipe of the bypass line 7 to block the bypass line 7. There is. Therefore, at the time of start-up, first, the heating device 13 heats the piping forming the bypass line 7 while controlling the temperature control device 11 so that the temperature level is always at an appropriate level. Thereby, after confirming that the gas temperature in the pipe reaches the dew point or higher, the fan 12 is started.

At the end of the boiler operation, the flue gas in the bypass line 7 is sufficiently replaced with air, and the fan 12 and the heating device 13 are stopped after the replacement is completed. As a result, the gas temperature in the bypass line 7 drops below the dew point to cause dew condensation, and the fly ash in the gas is slurried due to the water contained in the flue gas and adheres to the inner wall of the pipe to block the bypass line 7. It is possible to prevent the occurrence of malfunctions and to stabilize the flow of the flue gas in the bypass line 7.

[0016]

As described above, according to the present invention, as is apparent from the above embodiment, the following effects can be obtained. (1) By shortening the length of the sampling probe to the minimum, the sampling response time can be shortened, and the clogging due to the sedimentation of the fly ash during the flue gas suction suspension can be suppressed. (2) By adopting one or more flue gas branch nozzles having one or more suction holes, flue sampling can be performed from a flue having a large cross-sectional area with further improved sample reliability. (3) Flow of the flue gas in the bypass line by forming the pipe of the bypass line into a downward flow including obliquely downward or by maintaining the bypass line pipe at an appropriate temperature by a heating device and a temperature control device. Allows to get stabilization. (4) By providing the position of the flue gas suction part of the bypass line on the upstream side of the flue gas flow relative to the position of the flue gas return part, the flue pressure loss during this time is used to increase the boosting capacity of the fan. It may be reduced or the fan itself may be omitted to reduce equipment and operating costs. (5) Moisture in the flue gas is heated by heating the bypass line piping to an appropriate temperature in advance and then starting the fan, and when the bypass line is fully replaced with air and then stopping the fan and heating device. It is possible to prevent the clogging of the inside of the pipe due to and to stabilize the flow of the flue gas.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a device for measuring unburned content in ash in a boiler exhaust gas according to claim 1.

FIG. 2 is a diagram showing a measurement position of a device for measuring unburned matter in ash in a boiler exhaust gas according to claim 2;

FIG. 3 is a partially enlarged view showing the configuration of a measuring device for measuring unburned content in ash in boiler exhaust gas in FIG.

FIG. 4 is a diagram showing a position of a flue gas sampling unit in a conventional art example.

5 is a partially enlarged view showing the configuration of the flue gas sampling unit in FIG.

[Explanation of symbols]

 1 Furnace 2 Second flue 3 Air preheater 4 Flue gas denitration device 5 Unburned ash content meter 6 Sampling probe 7 Bypass line 8 Flue gas branch nozzle 9 Flue gas return nozzle 10 Suction hole 11 Temperature controller 12 Fan 13 Heating device 14 Measuring position of unburned ash in boiler exhaust gas 51 Furnace 52 Second flue 53 Air preheater 54 Flue gas sampling unit 55 Sampling probe 56 Ash unburned meter 57 Measuring unit 58 Vacuum pump

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Fujiwara, Daigasakihama, Shichigahama, Miyagi-gun, Miyagi Prefecture Maejima No. 1 in Todai Electric Power Co., Inc. First place Tohoku Electric Power Co., Inc. Sendai Thermal Power Plant (72) Inventor Eiichi Harada 1-1 Kawasaki-cho, Akashi-shi, Hyogo Prefecture Kawasaki Heavy Industries, Ltd. Akashi Technical Research Institute (72) Akira Mihara Kawasaki-cho, Akashi-shi, Hyogo Prefecture 1-1 Kawasaki Heavy Industries Ltd. Akashi Plant (72) Inventor Toshihiro Takano 2-4-25 Minamisuna, Koto-ku, Tokyo Kawasaki Heavy Industries Ltd. Tokyo Design Office (72) Toshihiro Kitaguchi Minamisuna, Koto-ku, Tokyo 2-4-25 Kawasaki Heavy Industries Ltd. Tokyo Design Office

Claims (3)

[Claims] 1. A system for continuously analyzing unburned ash in fly ash in a flue gas of a boiler such as pulverized coal-fired using a continuous analyzer for unburned ash in an ash, wherein at least one suction hole is provided. A flue gas suction section having at least one flue gas branching nozzle, and a pipe from the flue gas suction section through the flue gas sampling section to a flue gas return section downstream of the flue gas flow; Unburned ash gas that collects flue gas from a bypass line consisting of a fan, a temperature control device attached to the bypass line, and a sampling probe from inside the bypass line. An apparatus for measuring unburned ash content in flue gas from a boiler, comprising: 2. The apparatus for measuring unburned ash in boiler exhaust gas according to claim 1, wherein the piping of the bypass line is formed in a downward flow including an oblique downward direction. 3. The heating device heats the temperature of the flue gas in the bypass line to a temperature above the dew point of the gas, and then activates a fan forming the bypass line to sufficiently replace the flue gas in the bypass line with air. The method for operating the measurement device for measuring unburned ash in boiler exhaust gas according to claim 1 or 2, wherein the fan and the heating device are stopped later.