CN201075066Y - Fog droplet sampling system - Google Patents

Abstract

The utility model discloses a droplet sampling system and is characterized in that the utility model comprises a droplet collecting device (1) and a sampling pipe (2); the droplet collecting device (1) is a cylinder shape and consists of an upper round pipe (5), a middle round pipe (4) and a lower round pipe (3) which are connected with each other; the two ends of the middle round pipe (4) are enclosed and the middle thereof is provided with a condensation pipe (4a) which is communicates the upper round pipe (5) and the lower round pipe (3); the upper end of the middle round pipe (4) is covered by a filter paper (7); the upper end of the upper round cylinder (5) is enclosed and extended by a flue output pipe (5a); the lower end of the lower round cylinder (3) is sealed and the side wall thereof is extended by a suction nozzle (3a); the droplet collecting device (1) is fixed on the external wall of the sampling pipe (2); the flue output pipe (5a) is connected with the lower pipe port of the sampling pipe (2) through a soft pipe (8); the upper end of the sampling pipe (2) is sequentially connected with a vacuum pump (9) and a wet-typed gas meter (10). The utility model has simpler measurement and operation and exacter measurement results.

Description

Droplet Sampling System

technical field

The utility model belongs to a sampling system in the desulfurization field, in particular to a droplet sampling system in desulfurization flue gas.

Background technique

During the operation of the wet desulfurization absorption tower, it is easy to generate "fog" with a particle size of 10-60 microns. The "fog" not only contains water, but also dissolves sulfuric acid, sulfate, _SO2 , etc. The "fog" of the chimney will simultaneously bring SO ₂ into the atmosphere, causing fouling and corrosion of fans, heat exchangers and flues. Therefore, wet desulfurization requires defogging of the absorption tower in terms of technology, and the purified flue gas must be defogged before leaving the absorption tower. The mist eliminator is the main equipment for flue gas demisting, and its demisting effect will directly affect the continuous and reliable operation of each system of FGD.

The working principle of the mist eliminator is: the desulfurized flue gas flows through the curved channel of the mist eliminator at a certain speed, and the flue gas is quickly and continuously changed the direction of movement. Due to the centrifugal force and inertia, the droplets in the flue gas hit When the mist is collected on the blades of the demister, the mist droplets gather to form a water flow, and fall into the slurry tank under the action of gravity to realize the separation of gas and liquid, thereby achieving the effect of demisting.

The droplet concentration is an important index to investigate the defogging effect of the demister. Under normal operating conditions, the droplet concentration in the flue gas at the outlet of the demister is required to be lower than 75mg/Nm ³ .

At present, the method of testing the concentration of fog droplets in engineering mainly adopts the magnesium ion tracer method: first use a smoke sampler to sample, and the fog droplets in the flue gas are condensed in the tank through the condensation tank, and rinse the condensation tank with double distilled water after sampling , analyze the Mg ²⁺ concentration in the droplets after constant volume; analyze the Mg ²⁺ concentration in the slurry filtrate at the same time, and finally calculate the droplet concentration according to the two Mg ²⁺ concentration values. The main problem of this method is the large error, because the content of magnesium ions in the slurry and smoke droplets is very low, the experimental error is very large, and it needs to be analyzed by sophisticated equipment such as atomic absorption spectroscopy.

Utility model content

The problem to be solved by the utility model is to provide a droplet sampling system with simple operation and accurate measurement.

The technical scheme of the utility model is as follows: a droplet sampling system, including a droplet collection device and a sampling tube, the droplet collection device is cylindrical, and is composed of an upper circular tube, a middle circular tube, and a lower circular tube. Both ends of the central circular tube are closed, and a condensation pipe connecting the upper and lower circular tubes is arranged in the middle. The upper end of the central circular tube is covered with filter paper, and the upper end of the upper cylinder is closed, and a flue gas output pipe extends out. The lower end of the lower cylinder is sealed, and a suction nozzle protrudes from the side wall. The droplet collection device is fixed on the outer wall of the sampling tube. Vacuum pump, wet gas meter.

In the design, the flexible tube is a silicone tube, and the condensation tube is in a spiral shape. In order to prevent air leakage, the sampling tube and the droplet collection device need to be bound together with sealing tape, and at the same time, the joints between the upper, middle and lower round tubes of the droplet collection device should also be tightly wrapped with sealing tape.

When collecting mist, first open the short tube cover of the sampling hole, slowly insert the sampling tube (keep the suction nozzle facing away from the flue gas flow direction) to the sampling point, and fix the flange on the sampling tube to the short tube port with a fixing clip. Turn on the vacuum pump, adjust the wet gas meter to zero, tighten the air flow regulating valve, and turn off the vacuum pump; rotate the sampling pipe until the suction nozzle is facing the direction of the flue gas flow; turn on the vacuum pump, and adjust the air flow control valve (adjust quickly) to the flow rate indicated by the gas meter. The calculated flow rate is equal and the thermometer measures the temperature. After inhaling at a constant speed for a period of time, rotate the sampling tube so that the suction nozzle faces away from the flue gas flow, record the volume readings and pressure readings on the wet gas meter, then slowly take out the sampling tube and cover the short tube cap. Take off the droplet collection device, take it back to the laboratory and weigh it, and subtract it from the initial weight to get the droplet weight. The droplet concentration is calculated by the formula.

Beneficial effects: the utility model adopts the method of smoking smoke at a constant speed, the mist in the flue gas is collected by the collecting device, and the mass of the mist can be obtained by weighing the weight of the mist collecting device before and after collection, and then the mist is obtained through the formula drop concentration. This method does not require sophisticated equipment such as atomic absorption spectroscopy for measurement, the operation is simpler, and the measurement results are more accurate.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described:

As shown in Figure 1, the droplet sampling system of the present utility model comprises a droplet collection device 1 and a sampling tube 2. 3 connected components, the two ends of the middle circular pipe 4 are closed, and the condensation pipe 4a connecting the upper and lower circular pipes 5 and 3 is arranged in the middle, the upper end of the middle circular pipe 4 is covered with a filter paper 7, and the upper end of the upper cylinder 5 is closed And stretch out a flue gas output pipe 5a, the lower end of the lower cylinder 3 is sealed, and a suction nozzle 3a protrudes from the side wall, the droplet collection device 1 is fixed on the outer wall of the sampling pipe 2, and the flue gas output pipe 5a is connected to the outer wall of the sampling pipe 2. The nozzles at the lower ends of the sampling tubes 2 are connected by a hose 8 , and the upper ends of the sampling tubes 2 are connected with a vacuum pump 9 and a wet gas meter 10 in sequence.

The hose 8 is a silicone tube; the condensation pipe 4a is spiral. The sampling tube and the droplet collection device 1 are bundled together with sealing tape, and the joints between the upper, middle and lower round tubes 5, 4, and 3 of the droplet collection device 1 are tightly wrapped with sealing tape.

Working principle: first open the short tube cover of the sampling hole, slowly insert the droplet sampling tube 2 (keep the suction nozzle facing away from the flue gas flow direction) to the sampling point, and fix the flange plate at the upper end of the droplet sampling tube 2 on the short tube with a fixing clip verbal. Connect the sampling tube 2 with the vacuum pump 9 and the wet gas meter 10; turn on the vacuum pump 9, set the wet gas meter 10 to zero, tighten the air flow regulating valve, and turn off the vacuum pump 9; rotate the sampling tube 1 until the suction nozzle 6a faces the flue gas Flow direction: turn on the vacuum pump 9, adjust the air flow control valve (adjust quickly) until the flow rate indicated by the gas meter is equal to the smoke flow rate calculated by the "L" type Pitot tube measurement, and the thermometer measures the temperature t. After constant inhalation for a period of time, rotate the sampling tube 2 so that the suction nozzle 3a faces away from the flue gas flow. At this time, the volume reading on the wet gas meter 10 is the value of L; the pressure reading is the value of Pm, and then slowly take out the sample tube, capped with a short tube cap. Take off the droplet collection device 1, take it back to the laboratory and weigh it, and subtract it from the initial weight to get the value of the droplet weight as m. Atmospheric pressure Pa is 746.17mmHg; check the Pv value according to the temperature t measured by the above-mentioned thermometer. Calculate the droplet concentration according to the following formula. Droplet concentration=m×1000/[(Pa+Pm-Pv)×273.15×V/(273.15+t)/760]]

Claims (3)

1. A droplet sampling system is characterized in that: comprise droplet collection device (1), sampling tube (2), described droplet collection device (1) is cylindrical, by last circular tube (5), middle part The round pipe (4) and the lower round pipe (3) are connected, and the two ends of the middle round pipe (4) are closed, and the condensation pipe (4a) connecting the upper and lower round pipes (5, 3) is arranged in the middle. The upper end of the tube (4) is covered with filter paper (7), the upper end of the upper cylinder (5) is closed and a flue gas output pipe (5a) extends out, the lower end of the lower cylinder (3) is sealed, and the side wall protrudes There is a suction nozzle (3a), the droplet collection device (1) is fixed on the outer wall of the sampling pipe (2), and a hose (8 ), the upper end of the sampling pipe (2) is connected to the vacuum pump (9) and the wet gas meter (10) in sequence. 2. The droplet sampling system according to claim 1, characterized in that: the flexible tube (8) is a silicone tube; the condensation tube (4a) is in a spiral shape. 3. The droplet sampling system according to claim 1, characterized in that: the sampling tube and the droplet collection device (1) are bound together with sealing tape, and the upper, middle, and The joints between the lower round pipes (3, 4, 5) are wrapped tightly with sealing tape.

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