Method and device for efficiently trapping polychlorinated dibenzodioxin / furan in incineration flue gas

Abstract

The invention discloses a method and a device for efficiently trapping polychlorinated dibenzodioxin / furan in incineration flue gas, and the specific improvement is as follows: after particulate matters are trapped by a fiber filter membrane, residual water vapor and other gaseous components enter a condenser to complete the separation of water and gaseous components, the water separately passes through XAD2 resin, the gaseous components also separately pass through the XAD2 resin, and the residual water vapor and other gaseous components enter the condenser to complete the separation of the water and the gaseous components; and respectively trapping dioxin therein. The outlet of the gaseous component trapping XAD2 and the outlet of the moisture trapping XAD2 are provided with a water level control pipe and a three-way proportional valve, and the outlet of the three-way proportional valve is connected with the sampler system control unit and is used for extracting flue gas. The flow ratio of the gaseous component trapping XAD2 to the moisture trapping XAD2 is adjusted by adjusting the opening degree of the three-way proportional valve, and it is ensured that the gaseous component trapping XAD2 extracts gaseous components, and the moisture trapping XAD2 extracts condensate water. The device has the characteristics of simple structure, convenience in operation and few steps. The collection efficiency of sampling dioxin in incineration flue gas is improved, and the complex process in the sample collection and preparation process is effectively reduced.

Description

Technical Field

[0001] The invention relates to a highly efficient capture method of polychlorinated dibenzodioxins / furans in incineration flue gas, belonging to the field of polychlorinated dibenzodioxins / furans (PCDD / Fs) sampling in incineration flue gas. Background Art

[0002] Polychlorinated dibenzodioxins / furans (hereinafter referred to as dioxins) are highly toxic substances, mainly derived from industrial pollution sources such as metal smelting, waste incineration and papermaking, and have the characteristics of environmental persistence, long-distance transmission, bioaccumulation and high toxicity. As an important environmental pollutant, dioxins have received widespread attention from governments around the world and have become one of the first 12 persistent organic pollutants selected by the Stockholm Convention.

[0003] At present, the collection of flue gas dioxins requires the simultaneous collection of particulate matter, moisture and gaseous components. The mainstream method is the filtration-cooling-adsorption method, which has two application branches. One is to cool the moisture and gaseous components after collecting particulate matter through the fiber filter membrane. The cooled gaseous components pass through the XAD2 resin and are captured by XAD2, while the moisture is collected separately. The advantage is that the gaseous components pass through XAD2 alone, and the capture efficiency is high. The disadvantage is that the moisture requires liquid-liquid extraction, and there is more moisture in long-term sampling, which increases the difficulty of sample collection and preparation. The other is to cool the moisture and gaseous components after collecting particulate matter through the fiber filter membrane. The cooled moisture and gaseous components pass through the XAD2 resin and are captured by XAD2 at the same time. The advantage is that the capture is simple and there is no need to collect and prepare the moisture separately. The disadvantage is that the gaseous components and moisture pass through XAD2 at the same time, the dioxin capture efficiency is low, and there is penetration, which is more obvious during long-term sampling.

[0004] The invention provides an efficient dioxin capture technology, which improves the dioxin capture efficiency and does not require separate collection and preparation of water, and is suitable for long-term sampling of dioxins in incineration flue gas. Summary of the invention

[0005] The purpose of the present invention is to improve the collection efficiency of dioxin sampling in incineration flue gas and effectively reduce the complex process in sample collection and preparation. The invention has the characteristics of simple structure, convenient operation and few steps.

[0006] The present invention provides an improved method for collecting dioxins from incineration flue gas by filtering, cooling and adsorbing. The technical solution adopted by the present invention is:

[0007] Through single-pump single-channel air extraction, the dioxins in condensed water and gaseous components can be captured separately, which improves the sample capture efficiency and reduces the difficulty of subsequent sample preparation, especially for long-period sampling. The technical solution adopted by the present invention is:

[0008] The incineration flue gas is at 120℃-125℃; firstly, the particulate matter is captured by the fiber filter membrane, and the remaining gas moisture (i.e. water vapor) and other gaseous components enter the condenser to complete the separation of moisture and gaseous components, and the condenser temperature is kept below 20℃. Moisture passes through the XAD2 resin alone, and the gaseous components also pass through the XAD2 resin alone. The moisture and gaseous components are collected through the same air extraction metering system; the dioxins are captured separately; the moisture passes through the XAD2 resin alone and enters the water level control tube with the measurement function of the capacitive liquid level sensor; the water level control tube is connected to the two-way proportional valve; the opening of the two-way proportional valve is controlled by the sampling system, and the flow ratio of the gaseous component capture XAD2 and the moisture capture XAD2 is adjusted by adjusting the opening of the two-way proportional valve to ensure that the gaseous component capture XAD2 captures the gaseous component, and the moisture capture XAD2 captures the condensed water; ensure that the gaseous component does not pass through the moisture capture XAD2.

[0009] Furthermore, in the above technical solution, a capacitive liquid level sensor is installed at the lowest limit and the highest limit of the outside of the water level control pipe, and the sensor liquid level signal is received by the sampling control system; the opening of the two-way proportional valve is controlled according to the capacitive liquid level sensor signal received by the sampling system to ensure that the liquid level in the water level control pipe is not lower than the lowest limit and not higher than the highest limit.

[0010] Furthermore, in the above technical solution, the core of the present invention is to complete the collection of moisture and gaseous components through dual flow distribution control and single-channel air extraction. The system control unit of the present invention adds the measurement function of the capacitive liquid level sensor and the valve opening adjustment function of the two-way proportional valve, and adjusts the flow ratio of the gaseous component capture XAD2 and the moisture capture XAD2 by adjusting the opening of the two-way proportional valve, ensuring that the gaseous component capture XAD2 captures the gaseous components and the moisture capture XAD2 captures the condensed water.

[0011] Furthermore, in the above technical solution, the present invention adds a water level control pipe after the water capture XAD2, and distributes the flow ratio of the gaseous component capture XAD2 and the water capture XAD2 by adjusting the opening of the two-way proportional valve according to the liquid level of the water level control pipe. In specific operation, it is ensured that the liquid level in the water level control pipe is not lower than the minimum limit and not higher than the maximum limit.

[0012] Furthermore, in the above technical solution, the water level control tube is a glass tube equipped with a liquid level sensor, and the internal volume is between 5-25 ml.

[0013] Furthermore, in the above technical solution, the two-way proportional valve is an electrically controlled two-way valve.

[0014] The core of the present invention is to complete the collection of moisture and gaseous components through dual flow distribution control and single-channel air extraction.

[0015] The present invention provides a device for collecting dioxins in incineration flue gas, comprising a fiber filter (1); a condenser (2); a condensed water and dry flue gas outlet (3); an air guide pipe (4); a gaseous component outlet (5); a gaseous component capture XAD2 (6); a condenser water outlet (7); a water capture XAD2 (8); a water level control tube (9); a capacitive liquid level sensor (10); and a two-way proportional valve (11). According to the dioxin capture process, the front end of the fiber filter (1) is connected to the flue gas sampling port, and the rear end is connected to the condensate and dry flue gas pipeline in the condenser (2). The condenser cools the flue gas to 20°C by cooling water. The bottom of the condensate and dry flue gas pipeline is provided with a condensate and dry flue gas outlet (3). The flue gas discharges the condensate and dry flue gas from the condenser condensate and dry flue gas outlet (3) to the inside of the condenser at the same time. A gaseous component outlet (5) is provided at the upper part of the condenser. The gaseous component outlet (5) is connected to the gaseous component capture XAD2 (6). A condenser water outlet (7) is provided at the lower part of the condenser. The condenser water outlet (7) is connected to the water capture XAD2 (6). D2 (8); the air guide pipe (4) is located inside the condenser (2), and the top of the air guide pipe (4) is connected to the gaseous component outlet (5); the condensed water and dry flue gas outlets (3) are respectively connected to the bottom of the air guide pipe (4) and the condenser water outlet (7); the moisture capture XAD2 (8) is connected to the water level control pipe (9), and a capacitive liquid level sensor (10) is installed on the water level control pipe (9); the outlet of the water level control pipe (9) is connected to a two-way proportional valve (11), and the outlet of the two-way proportional valve (11) is respectively connected to the gaseous component capture XAD2 (6) and the sampler system control unit through a three-way valve for extracting flue gas.

[0016] In addition to the conventional isokinetic sampling control function, the system control unit of the present invention is further provided with a measuring function of a capacitive liquid level sensor (10) and a valve opening adjustment function of a two-way proportional valve (11) in accordance with the change of the water level of a water level control pipe (9). By adjusting the opening of the two-way proportional valve (11), the flow ratio of the gas component capture XAD2 (6) and the water capture XAD2 (8) is adjusted, thereby ensuring that the gas component capture XAD2 (6) extracts gaseous components and the water capture XAD2 (8) extracts condensed water.

[0017] Furthermore, in the above technical solution, the water level control tube is a glass tube equipped with a liquid level sensor, and the internal volume is between 5-25 ml.

[0018] Furthermore, in the above technical solution, the two-way proportional valve is an electrically controlled two-way valve. The core of the present invention is to complete the collection of moisture and gaseous components through dual flow distribution control and a single-channel air extraction method.

[0019] In this way, through single-pump single-channel vacuuming, condensed water and gaseous components can be captured separately at the same time, which improves the sample capture efficiency and reduces the difficulty of subsequent sample preparation. The advantages are obvious especially for long-period sampling. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of the device of the present invention;

[0021] 1. Fiber filter; 2. Condenser; 3. Condensate and dry flue gas outlet; 4. Air duct; 5. Gaseous component outlet; 6. Gaseous component capture XAD2; 7. Condenser water outlet; 8. Moisture capture XAD2; 9. Water level control tube; 10. Capacitive liquid level sensor; 11. Two-way proportional valve. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings.

[0023] Example 1

[0024] The device for collecting dioxins in incineration flue gas includes a fiber filter 1; a condenser 2; a condensate and dry flue gas outlet 3; an air duct 4; a gaseous component outlet 5; a gaseous component capture XAD26; a condenser water outlet 7; a moisture capture XAD28; a water level control tube 9; a capacitive liquid level sensor 10; and a two-way proportional valve 11. According to the dioxin capture process, the front end of the fiber filter 1 is connected to the flue gas sampling port, and the rear end is connected to the condensate and dry flue gas pipeline in the condenser 2. The condenser cools the flue gas to 20°C through cooling water. The bottom of the condensate and dry flue gas pipeline is provided with a condensate and dry flue gas outlet 3; the gaseous component outlet 5 is connected to the gaseous component capture XAD26; a condenser water outlet 7 is provided at the lower part of the condenser; the condenser water outlet 7 is connected to the moisture capture XAD28; the air duct 4 is located inside the condenser 2, and the top of the air duct 4 is connected to the gaseous component outlet Port 5; the condensed water and dry flue gas outlet 3 are respectively connected with the bottom of the air duct 4 and the condenser water outlet 7; the condensed water and dry flue gas outlet 3 are located at the position where the bottom of the air duct 4 is connected with the condenser water outlet 7; the moisture capture XAD28 is connected to the water level control pipe 9, and the water level control pipe 9 is installed with a capacitive liquid level sensor 10; the outlet of the water level control pipe 9 is connected to a two-way proportional valve 11, and the outlet of the two-way proportional valve 11 is respectively connected with the gaseous component capture XAD26 and the sampler system control unit through a three-way valve for extracting flue gas.

[0025] In addition to the conventional isokinetic sampling control function, the system control unit of the present invention adds the measurement function of the capacitive liquid level sensor 10 and the valve opening adjustment function of the two-way proportional valve 11 according to the water level change of the water level control pipe 9. By adjusting the opening of the two-way proportional valve 11, the flow ratio of the gas component capture XAD26 and the moisture capture XAD28 is adjusted to ensure that the gas component capture XAD26 extracts gaseous components and the moisture capture XAD28 extracts condensed water.

[0026] In this way, through single-pump single-channel vacuuming, condensed water and gaseous components can be captured separately at the same time, which improves the sample capture efficiency and reduces the difficulty of subsequent sample preparation. The advantages are obvious especially for long-period sampling.

[0027] Example 2

[0028] Using the device in Example 1, the incineration flue gas carrying dioxins passes through the sampling gun barrel and enters the fiber filter 1 heated to 120°C. The particulate matter in the flue gas is captured by quartz fiber or glass fiber, and the gaseous components and water vapor enter the condenser 2. Under the action of circulating cooling water, the condenser cools the flue gas components to 20°C, and the water vapor is cooled to condensed water. The gaseous components and condensed water are discharged from the condensed water and dry flue gas outlet 3 at the same time; the gaseous components enter the air guide pipe 4 and enter the gaseous component capture XAD26 from the gaseous component outlet 5, and the dioxins in the gaseous components are captured by the gaseous component capture XAD26; the condensed water enters the moisture capture XAD28 from the condenser outlet 7, and the dioxins in the condensed water are captured by the moisture capture XAD28. Condensed water enters the water level control pipe 9 from the moisture capture XAD28 under the negative pressure of exhaust gas. The capacitive liquid level sensor 10 installed on the water level control pipe 9 will measure the water level of the water level control pipe. The outlet of the water level control pipe 9 is connected to a two-way proportional valve 11. The outlet of the two-way proportional valve 11 is connected to the outlet of the gaseous component capture XAD26 and the control unit of the sampler system through a three-way connection for extracting flue gas. When the water level is lower than the water level control limit, the two-way proportional valve 11 is adjusted to increase the suction negative pressure of the moisture capture XAD28 to increase the suction flow rate. When the water level is higher than the water level control limit, the two-way proportional valve 11 is adjusted to reduce the suction negative pressure of the moisture capture XAD28 to reduce the suction flow rate, thereby redistributing the suction ratio of the gaseous component capture XAD26 and the moisture capture XAD28 to ensure the water level in the water level control pipe. In this way, it can be ensured that the gaseous component capture XAD26 captures all the dioxins in the gaseous components, and the moisture capture XAD28 captures all the dioxins in the condensed water, thereby achieving efficient capture of dioxins while realizing gas-liquid separation capture.

Claims

1. An improved method for collecting dioxins from incineration flue gas by filtering, cooling and adsorbing, characterized in that: At 120℃-125℃, the incineration flue gas first passes through the fiber filter membrane to capture particulate matter, and the remaining water vapor and other gaseous components enter the condenser to complete the separation of moisture and gaseous components. The moisture passes through the XAD2 resin alone, and the gaseous components also pass through the XAD2 resin alone. The moisture and gas components are extracted and collected through the same exhaust metering system; dioxins are captured separately; the moisture passes through the XAD2 resin alone and enters the water level control pipe with liquid level measurement function; the water level control pipe is connected to the proportional valve; the opening of the proportional valve is controlled by the sampling system, and the flow ratio of the gaseous component capture XAD2 and the moisture capture XAD2 is adjusted by adjusting the opening of the two-way proportional valve to ensure that the gaseous component capture XAD2 captures the gaseous component, and the moisture capture XAD2 captures the condensed water; ensure that the gaseous component does not pass through the moisture capture XAD2.

2. The method according to claim 1, characterized in that: Capacitive liquid level sensors are installed at the lowest limit and the highest limit on the outside of the water level control pipe, and the sensor level signal is received by the sampling control system; the opening of the proportional valve is controlled according to the capacitive liquid level sensor signal received by the sampling system to ensure that the liquid level in the water level control pipe is not lower than the lowest limit and not higher than the highest limit.

3. The method according to claim 1, characterized in that: The water level control tube is a glass tube equipped with a liquid level sensor.

4. The method according to claim 1, characterized in that: The two-way proportional valve is an electrically controlled two-way valve.

5. A device for collecting dioxins in incineration flue gas, characterized in that: The invention comprises a fiber filter (1); a condenser (2); a condensate and dry smoke outlet (3); an air guide pipe (4); a gaseous component outlet (5); a gaseous component capture XAD2 (6); a condenser water outlet (7); a moisture capture XAD2 (8); a water level control pipe (9); a capacitive liquid level sensor (10); and a two-way proportional valve (11). The rear end of the fiber filter (1) is connected to the condensate and dry smoke pipeline in the condenser (2), and the bottom of the condensate and dry smoke pipeline is provided with a condensate and dry smoke outlet (3); the upper part of the condenser is provided with a gaseous component outlet (5); the gaseous component outlet (5) is connected to the gaseous component capture XAD2 (6), and the lower part of the condenser is provided with a condenser The invention relates to a water outlet (7); the condenser water outlet (7) is connected to the moisture capture XAD2 (8); the air guide pipe (4) is located inside the condenser (2), and the top of the air guide pipe (4) is connected to the gaseous component outlet (5); the condensed water and dry smoke outlets (3) are respectively connected to the bottom of the air guide pipe (4) and the condenser water outlet (7); the moisture capture XAD2 (8) outlet is connected to the water level control pipe (9), and a capacitive liquid level sensor (10) is installed on the water level control pipe (9); the water level control pipe (9) outlet is connected to a two-way proportional valve (11), and the two-way proportional valve (11) outlet is respectively connected to the gaseous component capture XAD2 (6) and the sampler system control unit through a three-way connection.

6. The device according to claim 5, characterized in that: The water level control tube is a glass tube equipped with a liquid level sensor.

7. The device according to claim 5, characterized in that: The two-way proportional valve is an electrically controlled two-way valve.

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