CN112362417A - Double-pulse difference opposite-blowing flue gas sampling device and method - Google Patents

Abstract

A dual-pulse differential opposite blowing flue gas sampling device and method, which is composed of a backflushing sampling period and a non-backflushing sampling period alternately. During the backflush cycle, both the backflush pulse valve and the suction pulse valve are closed. The flue gas enters the inner cavity from the outer surface of the soot filter and then enters the inlet of the inner pipe. The backflushing pulse valve is opened and lasts for ΔT1 time, the gas in the backflushing preheating tube enters the inner cavity of the soot filter, the dust accumulated on the outer surface of the soot filter is backflushed, and the gas entering the inlet of the inner tube is the smoke in the inner cavity gas. At the end of ΔT1, the suction pulse valve is opened for ΔT2 time, the gas in the inner cavity flows to the vacuum tank, and the flue gas enters the inner cavity through the soot filter. The invention can realize backflushing without interruption of sampling, realize real continuous flue gas sampling, and provide conditions for improving the environmental protection monitoring level and the control quality of the environmental protection device.

Description

A dual-pulse differential phase blowing flue gas sampling device and method

technical field

The present invention relates to a flue gas sampling device and method, in particular to a dual-pulse differential opposite blowing flue gas sampling device and method.

Background technique

The continuous flue gas emission monitoring system (CEMS) is mainly based on the principle of extraction method. The monitoring system of this principle needs to first filter out the dust in the sample gas. The usual practice is to use high-temperature ceramic or metal filter elements. At a certain thickness, use compressed air to perform a backflush, and the duration is usually about 2 minutes. During backflushing, sampling is interrupted, during which flue gas analysis is suspended. Since the operation control of environmental protection systems such as denitration and desulfurization requires the values of flue gas components such as NOx and SO ₂ , the intermittent sampling and analysis caused by this long-term backflushing will adversely affect the control of the environmental protection system; for the CEMS used for environmental protection monitoring of the total exhaust, Data on pollutant emissions during backflushing are missing.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the above-mentioned problems, and to provide a dual-pulse differential opposite blowing flue gas sampling device and method, which can realize the backflushing without interrupting the sampling, realize truly continuous flue gas sampling, and improve the environmental protection monitoring level and environmental protection. Device control quality provides conditions.

For achieving the above object, the technical scheme adopted in the present invention is as follows:

A dual-pulse differential opposite blowing flue gas sampling device, comprising a backflushing buffer tank, a backflushing preheating pipe, a vacuum tank, a smoke filter, an inner pipe and a probe base installed on the wall of the flue, the probe base is provided with There is an inner pipe support sleeve, the inner pipe support sleeve is connected with the soot filter, one end of the inner pipe passes through the inner pipe support sleeve, and the other end extends into the soot filter. The inlet of the heat pipe is connected, the outlet of the vacuum tank is connected with the inlet of the backflushing preheating pipe through the suction pulse valve, the outlet of the backflushing preheating pipe is connected with the inner cavity of the smoke filter, and passes through the inner pipe support sleeve One end of the inner tube is connected to the sampler.

A further improvement of the present invention is that the inlet of the backflushing buffer tank of the backflushing buffer tank is connected to the compressed air system.

A further improvement of the present invention lies in that the vacuum tank inlet of the vacuum tank is connected with the air pump.

A further improvement of the present invention is that a tee is arranged at the outlet of the connected backflushing preheating pipe, one outlet of the tee is connected to the inner tube support sleeve, and the other outlet is connected to the inner cavity of the smoke filter.

A further improvement of the present invention is that the inner tube support sleeve includes a metal outer protective tube and an inner thermal insulation material, and the inner thermal insulation material is arranged in the metal outer protective tube.

A further improvement of the present invention is that a sealing structure is arranged between the inner tube and the metal outer protective tube.

A further improvement of the present invention is that the soot filter is a cylindrical ceramic filter with a filtration precision of 1 micron, one end of the soot filter is a closed end, and the other end is an open end.

A further improvement of the present invention is that the inner tube is arranged on the centerline of the soot filter.

A further improvement of the present invention is that both the backflushing pulse valve and the suction pulse valve are connected with a controller; one end of the inner tube passing through the inner tube support sleeve is connected to the sampling tube through the pipeline, and the sampling tube is connected to the sampler.

A method for sampling flue gas with double-pulse differential opposite blowing based on the above device, comprising a backflushing sampling period and a non-backflushing sampling period, and the backflushing sampling period and the non-backflushing sampling period are alternately performed; wherein,

The specific process of the non-backflushing sampling period is as follows: the backflushing pulse valve and the suction pulse valve are closed, the flue gas enters the inner cavity from the outer surface of the soot filter, and then enters the inlet of the inner pipe, and then enters the sampler through the inner pipe;

The specific process of the backflushing cycle is: the backflushing pulse valve is opened for ΔT1 time, the preheated gas in the backflushing preheating tube enters the inner cavity, the pressure of the inner cavity increases, and the dust accumulated on the outer surface of the soot filter is reversed. Blow, the flue gas in the inner cavity moves to the closed end of the soot filter and enters the sampler through the inner pipe;

At the end of ΔT1 time, the suction pulse valve is opened and lasts for ΔT2 time, the gas in the inner cavity flows to the vacuum tank through the backflushing preheating pipe, the pressure in the inner cavity drops, the flue gas enters the inner cavity through the soot filter, and enters the sampling through the inner pipe. After the ΔT2 time expires, it enters the non-backflushing sampling period.

Compared with the prior art, the present invention has the following beneficial effects:

In the present invention, a backflushing buffer tank, a backflushing preheating pipe, a vacuum tank, a smoke filter, an inner pipe and a probe base installed on the flue wall are arranged, and the probe base is provided with an inner pipe support sleeve, and the inner pipe supports The sleeve is connected with the soot filter, one end of the inner tube goes out of the inner tube support sleeve, and the other end extends into the soot filter. The outlet of the backflushing preheating pipe is connected with the inlet of the backflushing preheating pipe through the suction pulse valve, the outlet of the backflushing preheating pipe is connected with the inner cavity of the soot filter, and one end of the inner pipe passing through the inner pipe support sleeve is connected with the sampler. It can realize backflushing without interruption of sampling, and realize real continuous flue gas sampling, which provides conditions for improving the level of environmental protection monitoring and the control quality of environmental protection devices.

Continuous sampling consists of alternate backflush sampling periods and non-backflush sampling periods. All periodic samplers operate continuously, the flue gas is continuously drawn in from the inlet of the inner tube and discharged from the outlet of the sampler, and the discharged flue gas enters the analyzer. During the non-backflush period, both the backflush pulse valve and the suction pulse valve are closed. The flue gas enters the inner cavity from the outer surface of the soot filter and then enters the inlet of the inner pipe. The backflush cycle consists of 1 purge pulse and 1 backsuction pulse. The two pulses are out of phase, continuous in time but not overlapping. At the beginning of purging, the backflushing pulse valve is opened and lasts for ΔT1 time. During this period, the preheated gas in the backflushing preheating tube quickly enters the inner cavity of the soot filter, the pressure in the inner cavity rises, and the outside of the soot filter is increased. The dust accumulated on the surface is blown back, and at the same time, the flue gas in the inner cavity moves to the right, but due to the extremely short time, during ΔT1, the gas entering the inlet of the inner tube is still the flue gas in the original inner cavity. At the end of ΔT1, the suction pulse valve opens and lasts for ΔT2. The gas in the inner cavity flows rapidly to the vacuum tank through the backflushing preheating tube, the pressure in the inner cavity drops rapidly, and the flue gas enters the inner cavity through the soot filter quickly. At the end of ΔT2 , the cavity is filled with smoke. During ΔT2, the gas entering the inlet of the inner pipe is still flue gas. After ΔT2 ends, enter the non-backflushing sampling period. In this way, in the whole continuous sampling process, the gas entering the inlet of the inner pipe is flue gas, so as to achieve the purpose of full-time sampling.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Among them, 1-backflushing buffer tank; 2-backflushing pulse valve; 3-probe base; 4-flue inner wall; 5-backflushing preheating pipe; 6-vacuum tank; 7-suction pulse valve; 8- Inner tube support sleeve; 9-smoke filter; 10-inner cavity; 11-inner tube inlet; 12-back flush gas end point; 13-inner tube; 14-sampler; 15-sampling tube; 16-vacuum tank inlet; 17-backflush buffer tank inlet; 18-controller.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings.

Referring to Fig. 1, the dual-pulse differential phase blowing flue gas sampling device of the present invention includes a backflushing buffer tank 1, a backflushing pulse valve 2, a probe base 3, a backflushing preheating pipe 5, a vacuum tank 6, a backflushing Pulse valve 7, inner tube support sleeve 8, soot filter 9, inner tube 13, sampling tube 15, sampler 14, vacuum tank inlet 16, backflushing buffer tank inlet 17 and controller 18, etc. The above components are installed on the flue wall surface 4 through the probe base 3; the inlet 17 of the backflushing buffer tank is connected to the external compressed air system, and the inlet 16 of the vacuum tank is connected to the external air pump; The outlet of the vacuum tank 6 is connected to the inlet of the backflushing preheating pipe 5 through the parallel connection of the backflushing pulse valve 2 and the back-suction pulse valve 7 respectively; the outlet of the backflushing preheating pipe 5 is connected to the open end and the inner pipe of the soot filter 9 The support sleeve 8 is connected in a three-way manner; specifically, the inner tube support sleeve 8 is connected to the soot filter 9 and is located on the same straight line, the inner tube support sleeve 8 is arranged on the probe base 3, and the inner tube support sleeve 8 includes Thin-walled metal outer protective tube and internal thermal insulation material, the internal thermal insulation material is arranged in the thin-walled metal outer protective tube, the smoke filter 9 is a slender cylindrical ceramic filter, the filtration accuracy is 1 micron, and one end is closed , the other end is open. The inner tube 13 is positioned on the centerline of the soot filter 9 through the inner tube support sleeve 8; that is, one end (the inner tube outlet) of the inner tube 13 passes through the inner tube support sleeve 8, and the other end (the inner tube inlet 11) extends into the soot filter 9, and close to the inner wall of the soot filter 9. An inner cavity 10 is formed between the inner tube 13 and the inner wall of the soot filter 9, and a sealing structure is provided between the inner tube 13 and the inner tube support sleeve 8, so that the inner cavity 10 is sealed and isolated from the external air;

The soot filter 9 is connected and fixed with the probe base 3 through the inner tube support sleeve 8; the inner tube 13 is a stainless steel or quartz thin tube, and the inlet end of the inner tube 13 is close to the inner wall of the closed end of the soot filter 9, and retains 6 -10mm spacing. The outlet of the inner pipe 13 is connected to the inlet of the sampler 14 through the sampling pipe 15 . The sampler 14 includes an air extraction pump and a flue gas condensation dehumidifier, and the flue gas discharged from the sampler 14 is supplied to a downstream flue gas analyzer.

The dual-pulse differential phase blowing flue gas sampling method of the present invention comprises the following steps:

During operation, the vacuum tank 6 maintains a negative pressure below -80kPa through an external air pump; the backflushing buffer tank 1 maintains a positive pressure through an external compressed air system, usually between 100 and 300kPa.

Continuous sampling consists of alternate backflush sampling periods and non-backflush sampling periods. All the periodic samplers 14 operate continuously, the sample gas is continuously sucked in from the inlet 11 of the inner pipe, and discharged from the outlet of the sampler 14, and the discharged sample gas enters the analyzer.

During the non-backflushing period, the backflushing pulse valve 2 and the suction pulse valve 7 are both closed. The flue gas enters the inner cavity 10 from the outer surface of the soot filter 9 to be collected and then enters the inner pipe inlet 11 . The length of the non-backflushing sampling period is determined according to the characteristics of the flue gas filter 9 and the concentration of soot in the flue gas. The outer surface of the soot filter 9 is the end point 12 of the backflushing gas.

The backflush cycle includes 1 purge pulse (width ΔT ₁ ) and 1 back-suck pulse (period ΔT ₂ ). The two pulses are out of phase, continuous in time but not overlapping.

When the purging starts, the backflushing pulse valve 2 is opened and lasts for ΔT1. During this period, the preheated gas in the backflushing preheating pipe 5 quickly enters the inner cavity 10, the pressure of the inner cavity 10 increases, and the soot filter 9 The dust accumulated on the outer surface is blown back, and at the same time, the sample gas in the inner cavity 10 moves to the closed end of the soot filter 9, but due to the extremely short time, during ΔT1, the gas entering the inner tube inlet 11 is still the inner cavity at the beginning 10 in the sample gas.

At the end of ΔT1 time, the suction pulse valve 7 is opened and continues for ΔT2 time, the gas in the inner cavity 10 quickly flows to the vacuum tank 6 through the backflushing preheating pipe 5, the pressure in the inner cavity 10 drops rapidly, and the flue gas quickly passes through the soot filter 9 Entering the inner cavity 10, when the ΔT2 time ends, the inner cavity 10 is filled with the sample gas; during the ΔT2 time period, the gas entering the inner tube inlet 11 is still the sample gas.

After the ΔT2 time expires, enter the non-backflushing sampling period. In this way, in the whole continuous sampling process, the gas entering the inlet 11 of the inner pipe is the sample gas, so as to achieve the purpose of full-time sampling.

Claims (10)

1. A dual-pulse differential opposite blowing flue gas sampling device is characterized in that, comprising a backflushing buffer tank (1), a backflushing preheating pipe (5), a vacuum tank (6), a smoke filter (9), an inner A pipe (13) and a probe base (3) mounted on the flue wall (4), the probe base (3) is provided with an inner pipe support sleeve (8), the inner pipe support sleeve (8) and the smoke filter (9) are connected, one end of the inner tube (13) goes out of the inner tube support sleeve (8), the other end extends into the soot filter (9), and the outlet of the backflushing buffer tank (1) passes through the backflushing pulse valve (2) It is connected with the inlet of the backflushing preheating pipe (5), and the outlet of the vacuum tank (6) is connected with the inlet of the backflushing preheating pipe (5) through the suction pulse valve (7). ) is communicated with the inner cavity (10) of the fume filter (9), and one end of the inner tube (13) passing through the inner tube support sleeve (8) is connected to the sampler (14). 2 . The dual-pulse differential opposite blowing flue gas sampling device according to claim 1 , wherein the backflushing buffer tank inlet ( 17 ) of the backflushing buffer tank ( 1 ) is connected to the compressed air system. 3 . 3 . The dual-pulse differential phase blowing flue gas sampling device according to claim 1 , wherein the vacuum tank inlet ( 16 ) of the vacuum tank ( 6 ) is connected to an air extraction pump. 4 . 4. a kind of double-pulse differential opposite blowing flue gas sampling device according to claim 1, is characterized in that, the outlet of the connected backflushing preheating pipe (5) is provided with a tee, and an outlet of the tee is supported by the inner pipe The sleeve (8) is connected, and the other outlet is connected with the inner cavity (10) of the soot filter (9). 5 . The dual-pulse differential opposite blowing flue gas sampling device according to claim 1 , wherein the inner tube support sleeve ( 8 ) comprises a metal outer protective tube and an inner heat insulation material, and the inner heat insulation material is arranged on the metal Inside the outer protective tube. 6 . The dual-pulse differential opposite blowing flue gas sampling device according to claim 5 , wherein a sealing structure is provided between the inner pipe ( 13 ) and the metal outer protective pipe. 7 . 7. A kind of double-pulse difference opposite blowing flue gas sampling device according to claim 1, characterized in that, the soot filter (9) is a cylindrical ceramic filter, the filtration precision is 1 micron, and the soot filter (9) ) is a closed end at one end and an open end at the other end. 8 . The dual-pulse differential opposite blowing flue gas sampling device according to claim 1 , wherein the inner pipe ( 13 ) is arranged on the center line of the soot filter ( 9 ). 9 . 9. A kind of dual-pulse differential opposite blowing flue gas sampling device according to claim 1, characterized in that, the backflushing pulse valve (2) and the suction pulse valve (7) are both connected with a controller (18); One end of the inner tube (13) exiting the inner tube support sleeve (8) is connected to the sampling tube (15) through a pipeline, and the sampling tube (15) is connected to the sampler (14). 10. A method for sampling flue gas with double-pulse difference opposite blowing based on the device of claim 1, characterized in that, comprising a backflushing sampling period and a non-backflushing sampling period, and the backflushing sampling period and the non-backflushing sampling period are alternately performed. ;in, The specific process of the non-backflushing sampling period is as follows: the backflushing pulse valve (2) and the suction pulse valve (7) are closed, and the flue gas enters the inner cavity (10) from the outer surface of the soot filter (9) and then enters the inner pipe inlet for collection. (11), enter the sampler (14) through the inner pipe (13); The specific process of the backflushing cycle is as follows: the backflushing pulse valve (2) is opened for ΔT1 time, the preheated gas in the backflushing preheating pipe (5) enters the inner cavity (10), and the pressure of the inner cavity (10) rises. high, the dust accumulated on the outer surface of the soot filter (9) is blown back, and the flue gas in the inner cavity (10) moves to the closed end of the soot filter (9), and enters the sampler (14) through the inner pipe (13) ; At the end of the ΔT1 time, the suction pulse valve (7) is opened and continues for the ΔT2 time, the gas in the inner cavity (10) flows to the vacuum tank (6) through the backflushing preheating pipe (5), and the pressure of the inner cavity (10) drops, The flue gas enters the inner cavity (10) through the soot filter (9), enters the sampler (14) through the inner pipe (13), and enters the non-backflushing sampling period after the ΔT2 time expires.

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