CN209894557U

CN209894557U - SO in coal-fired flue gas3Second-stage sampling system

Info

Publication number: CN209894557U
Application number: CN201920381072.3U
Authority: CN
Inventors: 刘锡尧; 刘小刚; 张红飙; 叶兴联; 郑芳
Original assignee: LONGYAN INSTITUTE OF QUALITY INSPECTION FOR PRODUCTS; Fujian Longking Co Ltd.
Current assignee: LONGYAN INSTITUTE OF QUALITY INSPECTION FOR PRODUCTS; Fujian Longking Co Ltd.
Priority date: 2019-03-25
Filing date: 2019-03-25
Publication date: 2020-01-03
Anticipated expiration: 2029-03-25

Abstract

The utility model discloses a SO in coal-fired flue gas₃The second-stage sampling system comprises a sampling gun, a second-stage trapping device, a water bath device, a drying bottle and a sampling instrument; the sampling gun comprises an arc-shaped sampling nozzle, a ceramic filter element filter, a heat tracing band and a sampling pipeline, wherein the sampling nozzle is sequentially connected with the filter element filter and the sampling pipeline, and the heat tracing band is wrapped on the outer surface of the sampling pipeline; the secondary trapping device comprises an inner pipe of a spiral condenser pipe, an outer pipe with a water bath inlet and a water bath outlet and a filter membrane filtering device; filter elementThe membrane filtering device is a cylinder with two sections of semi-cylinders in threaded sealing connection, a filter membrane is arranged in the right semi-cylinder with a flue gas outlet, and the filter membrane is supported on a filter membrane supporting net and limited by a limiting block; the inner pipe, the outer pipe and the left semi-cylinder body are integrally formed by glass; the flue gas inlet of the condensing pipe is connected with the sampling pipeline, and the outlet of the condensing pipe is connected with the conical air hole and extends into the left semi-cylinder; the outer pipe and the water bath device form a circulating water bath; the smoke outlet is connected with the two-stage drying bottle and then connected with the air pump of the sampling instrument. The system has accurate and reliable sampling, stability and high efficiency.

Description

SO in coal-fired flue gas3Second-stage sampling system

Technical Field

The utility model relates to a coal fired boiler flue gas pollutant sampling equipment, concretely relates to SO in coal fired flue gas₃The two-stage sampling system of (1).

Background

With the continuous and rapid development of economy in China, the emission of various atmospheric pollutants is increased sharply, and at present, large coal-fired boilers in China are basically equipped with SCR denitration devices. But because the catalyst in the SCR device is easy to catalyze SO in the flue gas₂Formation of SO₃And SO₃Is easy to combine with the water vapor in the flue gas to form sulfuric acid vapor. When the wall temperature of the equipment is lower than the acid dew point, sulfuric acid vapor is condensed on the heated surface to cause acid dew point corrosion, SO₃The higher the concentration, the greater the corrosion window. Meanwhile, the SCR denitration device is provided with an inlet and an outlet SO₃Increment of (i.e. SO)₂/SO₃The conversion of (b) is an important index for evaluating the catalyst. In order to actively solve the problem of acid dew point corrosion and effectively evaluate the performance of the SCR catalyst, SO in a flue needs to be treated₃The concentration was tested accurately. But because of the complex components and SO of the coal-fired flue gas₃The chemical property is more active and the concentration is lower, and SO in the flue gas₃The concentration test difficulty is high, and the concentration test difficulty is always a difficulty in testing the coal-fired flue gas pollutants.

In order to solve the problems, a special sampling system is adopted for constant-speed sampling in the annex C of the GB/T21508-2008, a sampling gun is inserted into a flue, flue gas enters a condensing tube after passing through a filter and is communicated with a channelThe water bath device controls the temperature of the condensing pipe to ensure that SO in the flue gas₃Condensing and adsorbing on the inner wall of the condenser tube, washing the filter and the condenser tube with deionized water, and analyzing SO in the cleaning solution₄ ^2-SO as to calculate the SO in the flue gas₃The concentration of (c). According to the sampling process, SO₃The collecting efficiency is the key of the test accuracy, but the condensing pipes adopted by various large research institutions and test units cannot collect SO at present₃All collected and if only the condensing pipe is adopted to collect SO₃The accuracy of the test is greatly influenced.

Patent CN 105352784A discloses a method for testing SO in wet desulfurization clean flue gas₃The device comprises a heating sampling gun, a spiral condensing tube, a membrane device and a flue gas sampler, and the device collects the desulfurized clean flue gas at constant speed through the heating sampling gun, SO condensed on the surface of particulate matters in the flue gas₃And conversion of acid mist into gaseous SO₃Then into the filter cartridge and condenser tube, part of the SO₃Trapped by a spiral condensing tube, the residual enters a subsequent membrane device along with the flue gas to be trapped, and finally the collected SO is washed by alkaline solution₃. The existing defects are that: although the flue gas is subjected to heat tracing and filtering in the sampling process, and a membrane trapping device is adopted, aiming at the flue gas subjected to wet desulphurization, on one hand, the filter cartridge is easy to break in a filter cartridge filtering mode, and the filtering effect is influenced; SO on the other hand₃The condensation is easy to occur at the connecting section of the condensation pipe and the subsequent film trapping device, which causes loss.

Disclosure of Invention

The utility model aims at providing a SO is arranged in coal-fired flue gas₃Accurate and reliable, stable and efficient in sampling, small in sampling loss and long in service life of equipment₃The two-stage sampling system of (1).

To achieve the above purpose, the utility model relates to a SO in coal-fired flue gas₃The second-stage sampling system comprises a sampling gun, a second-stage trapping device, a water bath device, a drying bottle and a sampling instrument; the sampling gun comprises a polytetrafluoroethylene sampling nozzle, a ceramic sintered filter element filter, a heat tracing band and a polytetrafluoroethylene sampling tubeThe sampling pipe is characterized in that a sampling nozzle is arc-shaped, and then is sequentially connected with a ceramic sintered filter element filter and a polytetrafluoroethylene sampling pipe, and the outer surface of the polytetrafluoroethylene sampling pipe is wrapped by a heat tracing band; the secondary trapping device integrates a condenser pipe and a filter membrane trapping device and comprises a spiral condenser pipe serving as an inner pipe, an outer pipe with a water bath inlet and a water bath outlet and a filter membrane filtering device; the filter membrane filtering device is a cylinder formed by connecting a left half cylinder and a right half cylinder through threads, two ends of the cylinder are both closed hemispheres, a filter membrane is arranged in the right half cylinder of the flue gas outlet and close to the connecting port, and the filter membrane is supported on a filter membrane supporting block with a plurality of uniformly distributed small holes and is limited by a limiting block fixed in the right half cylinder; the inner tube, the outer tube and the left semi-cylinder of the filter membrane filtering device are integrally formed by adopting glass or quartz materials; the smoke inlet at the front end of the condensing pipe is connected with a polytetrafluoroethylene sampling pipeline, the smoke outlet at the rear end of the condensing pipe is connected with a conical air hole and extends into the left semi-cylinder of the filter membrane filtering device, and the conical air hole is beneficial to uniform diffusion of smoke; a water bath inlet arranged at the front end of the outer pipe is connected with a water outlet of the water bath device, and a water bath outlet arranged at the rear end of the outer pipe is connected with a water inlet of the water bath device to form circulating water bath; the smoke outlet is connected with the two-stage drying bottle through a pipeline and then connected with the air suction pump of the sampling instrument through a pipeline.

The flue gas inlet and the flue gas outlet are connecting pipes with the inner diameter of 10-12 mm and the wall thickness of 2-3 mm, and are convenient to connect with front and rear parts.

The inner diameter of the condensation pipe is 4-6 mm, and the diameter of the ring is 80-120 mm.

The inner diameter of the cylinder of the filter membrane filtering device is 80-120 mm.

And silicon oxide is filled in the two-stage drying bottle and is used for drying moisture in the flue gas and protecting the sampling instrument.

During the test, the filter membrane is installed on the filter membrane supporting shoe to it is fixed through the stopper, stopper and filter membrane are simultaneously screwed and are fixed together with filter membrane filter equipment's left half-section along with filter membrane filter equipment's right half-section screw, and the flue gas through the diffusion of toper gas pocket passes through the filter membrane with even velocity of flow. The filter membrane is preferably made of PTFE to prevent SO₃The fog drops react with the filter membrane or the filter membrane is damaged due to too much humidity.

The filter element filter adopts the sintered filter element made of ceramic materials, the gap is small, but the specific surface area is large, dust in smoke can be well filtered, and the heat tracing band is wrapped on the outer surface of the sampling pipeline and is used for tracing the sampling gun.

The utility model relates to a SO in coal-fired flue gas₃The technical problem to be solved by the secondary sampling system is to provide a sampling system suitable for SO in coal-fired flue gas₃The second-stage sampling system can stabilize and effectively filter dust in flue gas, optimize the size of the condenser pipe, and integrate the condenser pipe and the membrane trapping device simultaneously, thereby improving SO₃The collection efficiency of (1).

The utility model relates to a SO in coal-fired flue gas₃The two-stage sampling system has the following technical characteristics and beneficial effects:

1. the filter at the front end of the sampling gun is a sintered filter element filter made of ceramic materials, and can stably and effectively filter dust in smoke.

2. The second-stage trapping device integrates a condenser tube and a membrane trapping device, reduces loss in the sampling process, and improves SO₃The collection efficiency of (1).

3. The air hole between the condensation pipe and the membrane trapping device adopts a conical mode, so that the uniform passing of the flue gas through the membrane is facilitated, and the trapping efficiency is improved.

Drawings

FIG. 1 shows SO in coal-fired flue gas₃Schematic structural diagram of the two-stage sampling system.

Fig. 2 is a schematic diagram of the sampling gun of fig. 1.

FIG. 3 is a schematic view of the structure of the secondary trapping device of FIG. 1.

Reference numerals: the device comprises a sampling gun 1, a sampling nozzle 1-1, a filter element filter 1-2, a heat tracing band 1-3, a sampling pipeline 1-4, a secondary trapping device 2, a condenser pipe 2-1, a flue gas inlet 2-2, a conical air hole 2-3, a water bath inlet 2-4, a water bath outlet 2-5, a filter membrane 2-6, a limiting block 2-7, a flue gas outlet 2-8, a filter membrane supporting block 2-9, a water bath device 3, a drying bottle 4 and a sampling instrument 5.

Detailed Description

The following description is made in conjunction with the accompanying drawings and the detailed description of the invention for SO in coal-fired flue gas₃The two-stage sampling system of (1) is described in further detail.

As shown in figures 1-3, the utility model relates to a SO in coal-fired flue gas₃The second-stage sampling system comprises a sampling gun 1, a second-stage trapping device 2, a water bath device 3, a drying bottle 4 and a sampling instrument 5; the sampling gun 1 comprises a polytetrafluoroethylene sampling nozzle 1-1, a ceramic sintering filter element filter 1-2, a heat tracing band 1-3 and a polytetrafluoroethylene sampling pipeline 1-4, wherein the sampling nozzle 1-1 is arc-shaped, the ceramic sintering filter element filter 1-2 and the polytetrafluoroethylene sampling pipeline 1-4 are sequentially connected behind the sampling nozzle 1-1, and the outer surface of the polytetrafluoroethylene sampling pipeline 1-4 is wrapped by the heat tracing band 1-3; the secondary trapping device 2 comprises a spiral condensing pipe 2-1 serving as an inner pipe, an outer pipe with a water bath inlet 2-4 and a water bath outlet 2-5 and a filter membrane filtering device; the filter membrane filtering device is a cylinder formed by connecting a left half cylinder and a right half cylinder through glass threads so as to be convenient to assemble and disassemble, vaseline is coated in the cylinder for sealing, two ends of the cylinder are both closed hemispheres, a filter membrane 2-6 is arranged in the right half cylinder with a flue gas outlet 2-8 and close to a connecting port, the filter membrane 2-6 is supported on a filter membrane supporting block 2-9 with a plurality of small holes uniformly distributed and is limited by a limiting block 2-7 fixed in the right half cylinder, and the inner tube, the outer tube and the left half cylinder of the filter membrane filtering device are integrally formed by adopting a glass material; a flue gas inlet 2-2 arranged at the front end of the condensation pipe 2-1 is connected with a polytetrafluoroethylene sampling pipeline 1-4, a flue gas outlet at the rear end is connected with a conical air hole 2-3 and extends into a left semi-cylinder of the filter membrane filtering device, and the conical air hole is beneficial to uniform diffusion of flue gas; a water bath inlet 2-4 arranged at the front end of the outer pipe is connected with a water outlet of the water bath device 3, a water bath outlet 2-5 arranged at the rear end of the outer pipe is connected with a water inlet of the water bath device 3 to form a circulating water bath, and the water bath device is used for controlling the temperature of the condenser pipe to be constant at 65-85 ℃; the flue gas inlet 2-2 and the flue gas outlet are both connecting pipes with the inner diameter of 10-12 mm and the wall thickness of 2-3 mm, so that the connecting pipes are conveniently connected with the front part and the rear part; the inner diameter of the condensing pipe 2-1 is 4-6 mm, and the ring diameter is 100 mm; the inner diameter of the cylinder of the filter membrane filtering device is 100 mm; what is needed isThe flue gas outlet 2-8 is connected with a two-stage drying bottle 4 through a pipeline and then is connected with an air extracting pump of a sampling instrument 5 through a pipeline, silicon oxide is filled in the two-stage drying bottle 4 and used for drying moisture in flue gas, the sampling instrument is protected, and the sampling instrument is used as the rear end of the whole sampling device and used for providing power.

Before collecting a sample, connecting all parts according to the figures 1-3, setting the heat tracing temperature of a sampling gun to be 220-260 ℃, and stabilizing for 30 min; setting the temperature of a water bath device at 65-85 ℃ and stabilizing for 30 min; and (4) filling a proper amount of silica gel drying agent into the drying bottle, and finally carrying out air tightness inspection on the whole sampling system.

During sampling, the flue gas enters from a sampling nozzle 1-1, passes through a filter 1-2, enters a sampling pipeline 1-4 with heat tracing temperature of 220-260 ℃, then enters a secondary trapping device, and SO in the flue gas₃Condensed to form SO₃Fog droplets, due to centrifugal force, mostly SO₃The fog drops are attached to the inner wall of the condensation pipe, and part of the unattached SO₃The fog drops are captured when passing through the filter membrane along with the smoke, and finally the smoke is dried by a drying bottle and then is emptied.

Claims

1. SO in coal-fired flue gas₃The second-stage sampling system comprises a sampling gun, a second-stage trapping device, a water bath device, a drying bottle and a sampling instrument; the method is characterized in that: the sampling gun comprises a polytetrafluoroethylene sampling nozzle, a ceramic sintering filter element filter, a heat tracing band and a polytetrafluoroethylene sampling pipeline, wherein the sampling nozzle is arc-shaped and is sequentially connected with the ceramic sintering filter element filter and the polytetrafluoroethylene sampling pipeline, and the outer surface of the polytetrafluoroethylene sampling pipeline is wrapped by the heat tracing band; the secondary trapping device integrates a condenser pipe and a filter membrane trapping device and comprises a spiral condenser pipe serving as an inner pipe, an outer pipe with a water bath inlet and a water bath outlet and a filter membrane filtering device; the filter membrane filtering device is a cylinder formed by connecting a left half cylinder and a right half cylinder through threads, two ends of the cylinder are both closed hemispheres, a filter membrane is arranged in the right half cylinder of the flue gas outlet and close to the connecting port, and the filter membrane is supported on a filter membrane supporting block with a plurality of uniformly distributed small holes and is limited by a limiting block fixed in the right half cylinder; the inner pipe and the outer pipeThe left half cylinder of the tube and the filter membrane filtering device is integrally formed by adopting glass or quartz materials; the smoke inlet at the front end of the condensing pipe is connected with a polytetrafluoroethylene sampling pipeline, the smoke outlet at the rear end of the condensing pipe is connected with a conical air hole and extends into the left semi-cylinder of the filter membrane filtering device, and the conical air hole is beneficial to uniform diffusion of smoke; a water bath inlet arranged at the front end of the outer pipe is connected with a water outlet of the water bath device, and a water bath outlet arranged at the rear end of the outer pipe is connected with a water inlet of the water bath device to form circulating water bath; the smoke outlet is connected with the two-stage drying bottle through a pipeline and then connected with the air suction pump of the sampling instrument through a pipeline.

2. SO in coal-fired flue gas according to claim 1₃The two-stage sampling system is characterized in that: the flue gas inlet and the flue gas outlet are connecting pipes with the inner diameter of 10-12 mm and the wall thickness of 2-3 mm, and are convenient to connect with front and rear parts.

3. SO in coal-fired flue gas according to claim 1₃The two-stage sampling system is characterized in that: the inner diameter of the condensation pipe is 4-6 mm, and the diameter of the ring is 80-120 mm.

4. SO in coal-fired flue gas according to claim 1₃The two-stage sampling system is characterized in that: the inner diameter of the cylinder of the filter membrane filtering device is 80-120 mm.

5. SO in coal-fired flue gas according to claim 1₃The two-stage sampling system is characterized in that: and silicon oxide is filled in the two-stage drying bottle and is used for drying moisture in the flue gas and protecting the sampling instrument.