CN201226006Y - Instrument for measuring flue gas speed, small liquid droplet distribution and concentration in wet desulphurization system - Google Patents

Abstract

The utility model discloses a measuring instrument for flue gas velocity, small droplet distribution and concentration in a wet desulfurization system, which belongs to the technical scope of the smoke test in the wet desulfurization system. The measuring instrument includes a circular test hole on the bottom of the test cylinder body, a Pitot tube and a test piece support for loading test pieces are arranged inside the cylinder body, and a high-pressure gas source, a gas pipeline, and an electromagnetic commutator are provided. Gas control part composed of valve and cylinder. The cylinder is located in the test cylinder, and the upper and lower ends of the cylinder are respectively provided with an upper air intake hole and a lower air intake hole. The cylinder shaft is fixed at the center of the cylinder, and the lower end of the cylinder shaft is connected with the test piece support through a connecting pipe. Pitot tube, the sealing pad under the pitot tube is connected to the test piece holder, and is used to seal the test tube. The device has simple structure, low cost, convenient and flexible operation, and is suitable for operation in most environments.

Description

Measuring instrument for flue gas velocity, small droplet distribution and concentration in wet desulfurization system

technical field

The utility model belongs to the scope of the smoke test device in the wet desulfurization system, in particular to a wet test device which is applied to the distribution of smoke velocity in the front and back sections of the demister in the smoke desulfurization system of thermal power plants and the particle size and concentration test of small droplets in the smoke. Measuring instrument for flue gas velocity, small droplet distribution and concentration in French desulfurization system.

Background technique

In the wet desulfurization system, the flue gas flowing through the desulfurization tower carries small droplets into the demister. The demister can only remove the droplets with a particle size larger than the critical diameter, and basically does not remove the small droplets with a particle size of less than 30 microns. Effect. The small droplets are rich in ingredients such as calcium hydroxide and calcium sulfate. When the flue gas containing small droplets passes through the smoke-smoke heater (GGH) of the desulfurization system, the small droplets will adhere to the leaves of the GGH. Due to the high temperature of the leaves, the water is evaporated, and the calcium hydroxide (limestone) Components such as calcium sulfate and calcium sulfate are stuck on the blades, causing GGH blockage, increasing the GGH pressure difference, causing turbulent vibration and even stalling of the desulfurization system booster fan, affecting the safe and economical operation of the entire desulfurization system and even the entire unit. Therefore, measuring the particle size distribution and concentration of small droplets before and after the demister is helpful for judging the demisting effect of the demister, predicting the blockage state of the GGH, and providing guidance for the safe operation of the desulfurization system.

Due to the high flow rate, high humidity and high flue gas temperature behind the demister, the measurement environment is very harsh. At present, there is no test instrument for the particle size distribution of small droplets after the demister in the desulfurization system at home and abroad.

Therefore, there is a need for a device and method that can easily measure the flow velocity distribution of the flue gas before and after the demister of the desulfurization system, the particle size distribution and concentration of small droplets in the flue gas, so as to facilitate the demisting effect of the demister and evaluate the blockage state of GGH , and improve the reference for the safe operation of the desulfurization system.

Contents of the invention

The purpose of this utility model is that when the flue gas containing small droplets passes through the smoke-smoke heater (GGH) of the desulfurization system, the small droplets will adhere to the leaves of the GGH, and the water will be evaporated due to the high temperature of the leaves. However, calcium hydroxide (limestone) and calcium sulfate stick to the blades, causing GGH blockage, increasing the GGH pressure difference, causing turbulent vibration and even stalling of the booster fan of the desulfurization system, affecting the safe and economical operation of the entire desulfurization system and even the entire unit. In view of the shortcomings, a measuring instrument for flue gas velocity, small droplet distribution, and concentration in wet desulfurization system is provided, which is characterized in that the measuring instrument includes: a test cylinder and a gas control part, and is located in the test cylinder body There is a test hole on the bottom of the cylinder, and the top cover is fixed on the top of the cylinder. Inside the cylinder, there is a pitot tube and a test piece bracket for loading test pieces; a pitot tube is fixed under the test piece bracket, and the sealing gasket under the pitot tube is Connected to the test piece support; the gas control part is composed of a high-pressure gas source, a gas delivery pipe, an electromagnetic reversing valve and a cylinder. The cylinder is located in the test cylinder. It is fixed at the center of the cylinder, and the lower end of the cylinder shaft is connected with the test piece support through a connecting pipe; two silicone tubes are fixed on the test piece support, and the two silicone tubes are respectively connected to the total pressure tube and the static pressure tube of the Pitot tube.

The two silicone tubes are drawn out from one of the two holes on the top cover of the test cylinder and connected to the micromanometer, and the other hole is drawn out from the two air intake pipes of the cylinder.

The air delivery pipe includes an upper air intake pipe and a lower air intake pipe, and the upper air intake pipe and the lower air intake pipe communicate with the upper air intake hole and the lower air intake hole of the cylinder respectively.

The electromagnetic reversing valve is connected with the air intake holes at both ends of the cylinder through the intake pipe, and the electromagnetic reversing valve is switched between the upper and lower intake pipes.

The test piece is coated with a silicone film.

The utility model has the following advantages: the device has simple structure, low cost, convenient and flexible operation, and is suitable for operation in most environments. It is especially suitable for the test of the flue gas flow velocity before and after the demister in the flue gas desulfurization system of the thermal power plant and the small liquid droplets in the flue gas.

Description of drawings

Figure 1 is an exploded view of a measuring instrument for flue gas velocity, small droplet distribution, and concentration in a wet desulfurization system;

FIG. 2 is a schematic structural diagram of FIG. 1 .

Fig. 3 is a perspective view of the pitot tube and the test piece at the test position.

Fig. 4 is the perspective view of test piece and test piece support;

Fig. 5 is the perspective view of the test tube cap of the device shown in Fig. 1;

Figure 6 is a layout diagram of test holes.

Figure 7 is a test point layout diagram.

Detailed ways

The utility model provides a measuring instrument for flue gas velocity, small droplet distribution and concentration in a wet desulfurization system. The present invention will be described in detail below in conjunction with specific embodiments and accompanying drawings.

In the schematic structural diagrams of the measuring instrument for flue gas velocity, small droplet distribution, and concentration in the wet desulfurization system shown in Figure 1 and Figure 2, the measuring instrument is composed of a test cylinder and a gas control part. There is a test hole 3 on the bottom of the cylinder, the top cover 2 is fixed on the top of the cylinder 1, and a pitot tube 4 and a test piece bracket 6 for loading the test piece 5 are arranged inside the cylinder body 1; Pitot tube 4, the gasket 7 below the pitot tube 4 is connected on the test piece support 6; the gas control part is made up of a high-pressure gas source, a gas delivery pipe, an electromagnetic reversing valve and a cylinder, and the cylinder 10 is located in the test tube 1, and the cylinder 10 is fixed below the top cover 2 through the small screw hole 20, the upper air intake hole at the upper end of the cylinder 10 is connected to the upper air intake pipe 12, the lower air intake hole at the lower end is connected to the lower air intake pipe 11, and the electromagnetic switch is connected between the upper air intake pipe 12 and the lower air intake pipe 11. Directional valve 13, the total intake pipe 14 and the air intake hole of the electromagnetic reversing valve 13 are connected; the cylinder shaft 9 is fixed in the center of the cylinder 10, and the lower end of the cylinder shaft 9 is connected with the test piece support 6 through the connecting pipe 5. During the test Two silicone tubes are fixed on the sheet support 6, and the two silicone tubes are respectively connected to the total pressure tube 15 and the static pressure tube 16 of the pitot tube 4 (the pitot tube is a commonly used experimental test instrument, and there will be corresponding instructions on the manual), two The silicone tube is connected with the micromanometer 17 after one hole is drawn out from two holes 18 on the top cover 2 of the test cylinder 1, and the other hole is drawn out two intake pipes of the cylinder. Stretch out two silica gel tubes and be connected on the micromanometer 17 (as shown in Figure 2, 5).

The working principle of the measuring instrument is: before testing, the high-pressure gas enters the electromagnetic reversing valve 13 from the main intake pipe 14 under the control of the gas control part, and the upper intake pipe 12 and the lower intake pipe 11 respectively connect with the upper intake hole and the lower intake of the cylinder 10. The air hole is connected; the electromagnetic reversing valve 13 switches between the upper and lower intake pipes, and when the electromagnetic reversing valve 13 switches the high-pressure gas into the upper intake pipe 12 on the upper part of the cylinder, it pushes the cylinder shaft 9 down, driving the pitot tube 4 and the test piece support 6 and sealing gasket 7 descending, so that Pitot tube 4 and test piece 5 are exposed in the flue gas atmosphere to be measured (as shown in Figure 3); The flow rate of the incoming flue gas is read through the micromanometer 17 connected to it, and the small liquid droplets in the flue gas directly hit the test piece 5 on the test piece support 6, leaving traces; after a test time of 1-90s Finally, the high-pressure gas from the high-pressure gas source is switched into the lower part of the cylinder by the electromagnetic reversing valve 13, and the cylinder shaft 9 is pushed upward, driving the test piece support 6, the pitot tube 4 and the sealing gasket 7 to move upward, so that the test piece support 6 and the pitot tube 4 Back into the test cylinder 1, and the sealing pad 7 seals the test cylinder 1 at the same time. Take out the test cylinder 1 from the smoke atmosphere, and use the gas control part to control the test piece bracket 6 to protrude from the cylinder, and take out the test piece 5; the traces of small droplets on the test piece 5 are enlarged by a certain number of times under a digital microscope Afterwards, the photos were taken, and the traces of small droplets on the obtained test piece 5 were directly observed under a microscope to obtain the particle size distribution and concentration of the droplets.

的伸出和退回。另外，可以理解，诸如测试片5可以与本装置一起提供，也可以分别提供。The above-mentioned test cylinder body 1 is a cylindrical cylinder, on which a top cover 2 is connected to the cylinder body 1 through a large screw hole 19, and a circular test hole 9 is opened at the bottom of the cylinder for pitot tube 4 and test piece support

extension and retraction. In addition, it can be understood that, for example, the test piece 5 can be provided together with the device, or can be provided separately.

The test piece 5 preferably has a smooth plane coated with a silica gel film for recording the information of the small liquid droplets impacted on the test piece, and after the impact of the liquid droplets, the impact traces of the liquid can be well preserved.

As shown in Figure 2, the test cylinder is in the non-test state, the pitot tube 4 and the test piece 5 are located inside the test cylinder 1, and the test hole 9 is sealed by the gasket 7 at the same time, before the test cylinder 1 is placed in the smoke for measurement and the test After the end, the test cartridge is in this state.

FIG. 4 is a perspective view of the test piece and the test piece holder of the device shown in FIG. 1 . The test piece 5 is installed on the test piece holder 6 . In this way, the combination and disassembly of the test piece 5 and the test piece holder 6 can be realized conveniently.

Through the high-speed switching of the solenoid valve and the rapid push of the high-pressure gas cylinder, the pitot tube and the test piece can be quickly extended or withdrawn from the test cylinder, which can reduce the measurement error per unit time.

The specific process of obtaining the droplet size distribution from the droplet traces on the test piece is as follows:

Place the test piece under the electron microscope and magnify it by a certain magnification. The microscope can automatically distinguish the traces left by different small droplets in the test piece through the difference in sensitivity, count the number n of small droplets, and use the photosensitive principle to count The area F _i of the small droplet trace is analyzed, and the equivalent diameter of the small droplet is calculated as d _i .

${\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}\sqrt{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

The local velocity measured by the Pitot tube is v, the residence time of the test piece in the flue gas is t, the area of the test piece is s, and the density of small droplets is ρ, then the concentration of small droplets in the clean flue gas can be calculated by formula (2) :

$\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&rho;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 1.5</span>}}}{{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; svt\&pi;</span>}}^{\mathrm{<span\; class="notranslate">\; 0.5</span>}}}\mathrm{<span\; class="notranslate">\; mg</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Through the formula (1), the particle size of all the small droplets is calculated, thus the particle size distribution of the small droplets. Through formula (2), the concentration of small liquid droplets in the flue gas can be calculated.

Example 1

The device and measurement method were used to measure the flue gas flow rate, small droplet size distribution and concentration before and after the desulfurization demister in a power plant, so as to evaluate the on-site demisting effect of the demister. The top plan view of a power plant mist eliminator and its arrangement in the flue, and its test diagram is shown in Figure 6. After the flue gas comes out of the bubble tower, it flows through the demister in the direction indicated by the arrow, and the two red vertical thick solid lines in the middle represent the two-stage demister. Eight measuring holes from A1 to A8 are arranged 1m in front of the first-stage demister (as shown in Figure 6), and eight measuring points from T1 to T8 are arranged in each measuring hole (as shown in Figure 7). About 1m behind the outlet of the fogger, eight measuring holes B1-B8 are arranged at equal intervals (as shown in Figure 6), and each measuring hole is set with eight measuring points P1-P8 (as shown in Figure 7). Prepare a sufficient number of test pieces coated with silicone film before testing.

Measurement steps:

(1) Before the test, the high-pressure gas from the gas source is passed into the upper part of the cylinder 10 through the upper intake pipe 12 through the electromagnetic reversing valve 13, and the cylinder shaft 9 is pushed downward, and the cylinder shaft 9 further drives the Pitot tube 4 and the test piece support 6 to extend out Test hole 3, install test piece 5, and then pass the high-pressure gas into the lower part of cylinder 10 through the lower intake pipe 11 through the electromagnetic reversing valve, and push the cylinder shaft 9 upward, so that the pitot tube 4 and test piece 5 are retracted into the test cylinder 1 , and at the same time seal the test hole 1 through the gasket 7;

(2) Put the test cylinder 1 at a certain distance above the position to be tested, and place the pitot tube 4 and the test piece 5 at the test position instantly through the high-pressure gas, and face the direction of the incoming flow, so that the flow velocity and the gas in the flue gas can be measured. The small droplet hits the test piece 5 vertically;

(3) After testing for 1 to 90 seconds, record the measurement time and the reading of the micromanometer 17, put the pitot tube 4 and the test piece 5 back into the test cylinder 1 through high-pressure gas, and seal the test cylinder 1 at the same time. Take the test tube 1 out of the flue, extend the test piece bracket 6 out of the test tube 1, and take out the test piece 5;

(4) The test piece 5 is amplified and analyzed by an electron microscope, and the area F _i of small droplets and the number n of small droplets are obtained through automatic statistical analysis of the microscope. The area of the test piece can be calculated by measuring the side length with a ruler, and ρ is the density of the limestone slurry in the bubble tower, which can be measured by sampling in the power plant. Use the above parameters to calculate the particle size distribution and concentration of the small droplets by formulas (1) and (2).

It should be understood that these specific embodiments and drawings are only for the purpose of illustrating the present invention, and are not intended to limit the present invention. After reading the specification, those skilled in the art will be able to make various modifications, variations and corrections obviously, and these modifications, variations and corrections all fall within the scope of the present invention.

Claims (6)

1. In the wet desulfurization system velocity of flue gas, droplet distribute, the measuring instrument of concentration, it is characterized in that, described measuring instrument comprises: test barrel and gas control section, tube at the test barrel cylindrical shell has an instrument connection at the end, cylindrical shell top fixed roof is provided with a pitot tube and loads the test pieces support of test pieces in inner barrel; Fix a pitot tube under the test pieces support, the sealing gasket of pitot tube below is connected on the test horse; Described gas control section is made up of high-pressure air source, gas piping, solenoid directional control valve and cylinder, cylinder is positioned at test barrel, the upper and lower side of cylinder is provided with air admission hole, following air admission hole respectively, and cylinder axis is fixed on cylinder axis, is connected by connecting pipe between cylinder axis lower end and the test pieces support; Fix two silicone tubes on the test pieces support, two silicone tubes connect the stagnation pressure tube and the static tube of pitot tube respectively.
2. According to velocity of flue gas in the described wet desulfurization system of claim 1, droplet distribute, the measuring instrument of concentration, it is characterized in that, described gas piping comprises draft tube and lower inlet duct, and last draft tube and lower inlet duct are communicated with the last air admission hole and the following air admission hole of cylinder respectively.
3. 3. according to the measuring instrument of velocity of flue gas, droplet distribution, concentration in the described wet desulfurization system of claim 1, it is characterized in that described solenoid directional control valve is connected by the air admission hole of draft tube with the cylinder two ends, solenoid directional control valve switches between last lower inlet duct.
4. According to velocity of flue gas in the described wet desulfurization system of claim 1, droplet distribute, the measuring instrument of concentration, it is characterized in that described two draft tube two circular holes from the test barrel top cover are respectively introduced.
5. 5. according to the measuring instrument of velocity of flue gas, droplet distribution, concentration in the described wet desulfurization system of claim 1, it is characterized in that, scribble silica gel thin film on the described test pieces.
6. According to velocity of flue gas in the described wet desulfurization system of claim 1, droplet distribute, the measuring instrument of concentration, it is characterized in that, a hole two holes of described two silicone tubes from the top cover of test barrel is drawn the back and is connected with microbarograph, and two draft tube of cylinder are drawn in the another one hole.

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