Immediate leak detection device for flue gas sampling and immediate leak detection method for flue gas sampling

Abstract

An immediate leak detection device for flue gas sampling and an immediate leak detection method for flue gas sampling are provided in the present application. The immediate leak detection device for flue gas sampling is arranged on an exhaust pipe, and the immediate leak detection device for flue gas sampling includes: a control pipeline used to obtain a flue gas in the exhaust pipe; a sampling pipeline used to obtain the flue gas in the exhaust pipe; a four-way valve connected to the control pipeline and the sampling pipeline; an oxygen meter connected to the four-way valve, wherein the oxygen meter detects the flue gas from the control pipeline to obtain a first oxygen concentration value and detects the flue gas from the sampling pipeline to obtain a second oxygen concentration value; and a processor electrically connected to the oxygen meter, the processor configured to compare the first oxygen concentration value and the second oxygen concentration value, wherein when the difference between the first oxygen concentration value and the second oxygen concentration value is greater than a threshold, the leaking is occurred in the sampling pipeline.

Description

[Technical Field]

[0001] This invention relates to the field of gas sampling, and in particular to an instant leak detection device and method for flue gas sampling. [Previous Technology]

[0002] To comply with environmental protection regulations, factories in the industry are required to test their emitted flue gas according to the announced testing methods to determine its composition. Flue gas sampling is time-consuming (e.g., 2 hours), and the sampling pipeline needs to be airtight to ensure the representativeness / accuracy of the flue gas sample. If an airtightness problem occurs in the sampling pipeline (e.g., gas leakage), gases from outside the exhaust pipe will be sampled, making the composition of the flue gas sample unrepresentative of the flue gas in the exhaust pipe. Current flue gas sampling processes check the leakage rate of the sampling pipeline before and after sampling to confirm whether a leak has occurred. However, once a leak is confirmed, the flue gas sample obtained after a significant time investment becomes unrepresentative, or in other words, inaccurate, requiring resampling.

[0003] Existing flue gas sampling processes require taking multiple flue gas samples at different locations for testing. For example, sampling lines 20 are used to obtain flue gas samples at different depths of the same sampling port 11 on the exhaust duct 10 (e.g., a chimney) (as shown in Figures 1A and 1B) or at different sampling ports 11, 12, 13, and 14 on the exhaust duct 10 (as shown in Figure 2). The movement of sampling lines 20 at different locations may also lead to leaks. Furthermore, exhaust ducts 10 (e.g., chimneys) in the industry are typically quite tall. To more closely approximate the actual emitted flue gas, the sampling ports are usually located at high altitudes. This also means that high-altitude winds and environmental vibrations can cause the sampling lines 20 to loosen and leak.

[0004] Therefore, it is necessary to provide an instant leak detection device and method for flue gas sampling to solve the problems existing in conventional technology. [Summary of the Invention]

[0005] The purpose of this invention is to provide an instant leak detection device and a method for instant leak detection of flue gas sampling, which can instantly confirm whether a leak has occurred in the sampling pipeline during the flue gas sampling process. Once a leak occurs in the sampling pipeline, the operator can immediately stop sampling and confirm the leak point in the sampling pipeline.

[0006] To achieve the above objective, the present invention provides an instant leak detection device for flue gas sampling, which is installed on an exhaust pipe and includes: a control line for acquiring flue gas in the exhaust pipe; a sampling line for acquiring the flue gas in the exhaust pipe; a four-way valve connected to the control line and the sampling line; an oxygen analyzer connected to the four-way valve, the oxygen analyzer detecting the flue gas from the control line to obtain a first oxygen concentration value and detecting the flue gas from the sampling line to obtain a second oxygen concentration value; and a processor electrically connected to the oxygen analyzer to compare the first oxygen concentration value with the second oxygen concentration value, wherein when the difference between the first oxygen concentration value and the second oxygen concentration value is greater than a threshold, it is determined that the sampling line has leaked.

[0007] In one embodiment of the present invention, the threshold is between 0.15% and 0.75%.

[0008] In one embodiment of the present invention, the first oxygen concentration value of the flue gas from the control pipeline is between 6% and 19%, and the second oxygen concentration value of the flue gas from the sampling pipeline is between 6% and 19%.

[0009] In one embodiment of the present invention, the control pipeline includes: a dust removal unit, a water removal unit and a control gas sampling pump.

[0010] In one embodiment of the present invention, the sampling pipeline includes: a sampling component, a sampling host and a sampling pump.

[0011] In one embodiment of the invention, the control line is made of metal.

[0012] In one embodiment of the present invention, the sampling line is made of glass or Teflon.

[0013] The present invention also provides an instant leak detection method for flue gas sampling, comprising the following steps: sampling flue gas in an exhaust pipe using an instant leak detection device for flue gas sampling; switching the four-way valve to connect the control line to the oxygen analyzer; obtaining the flue gas in the exhaust pipe through the control line; detecting the flue gas from the control line using the oxygen analyzer to obtain a first oxygen concentration value; switching the four-way valve to connect the sampling line to the oxygen analyzer; obtaining the flue gas in the exhaust pipe through the sampling line; detecting the flue gas from the sampling line using the oxygen analyzer to obtain a second oxygen concentration value; and comparing the first oxygen concentration value with the second oxygen concentration value using the processor, wherein when the difference between the first oxygen concentration value and the second oxygen concentration value is greater than a threshold, it is determined that the sampling line has leaked.

[0014] In one embodiment of the present invention, the threshold is between 0.15% and 0.75%.

[0015] In one embodiment of the present invention, the first oxygen concentration value of the flue gas from the control pipeline is between 6% and 19%, and the second oxygen concentration value of the flue gas from the sampling pipeline is between 6% and 19%.

[0016] As described above, the control line and the sampling line can simultaneously acquire flue gas from the exhaust pipe. By switching the four-way valve, the oxygen analyzer can detect the first oxygen concentration value of the flue gas from the control line and the second oxygen concentration value of the flue gas from the sampling line. By comparing the first oxygen concentration value with the second oxygen concentration value, it can be confirmed whether the sampling line is leaking. This solves the problem in the prior art that it is necessary to wait until sampling to determine whether the sampling line is leaking, and it can also be confirmed immediately whether the sampling line is leaking. Once the sampling line leaks, the operator can immediately stop sampling and confirm the leak point of the sampling line.

Implementation Method

[0017] To make the above and other objects, features, and advantages of the present invention more apparent and understandable, preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Furthermore, the directional terms used in this invention, such as up, down, top, bottom, front, back, left, right, inside, outside, side, surrounding, center, horizontal, transverse, vertical, longitudinal, axial, radial, uppermost, or lowermost, are merely for reference to the accompanying drawings. Therefore, the directional terms used are for illustrating and understanding the present invention, and not for limiting the present invention.

[0018] Please refer to Figures 3 to 5. Figure 3 is a schematic diagram showing the connection between the control line and the oxygen analyzer of an instant leak detection device for flue gas sampling according to an embodiment of the present invention. Figure 4 is a schematic diagram showing the connection between the sampling line and the oxygen analyzer of an instant leak detection device for flue gas sampling according to an embodiment of the present invention. Figure 5 is a cross-sectional schematic diagram of the control line and the sampling line in an embodiment of the present invention. This embodiment provides an instant leak detection device 100 for flue gas sampling, which is installed on an exhaust pipe 10. The instant leak detection device 100 for flue gas sampling includes: a control line 110, a sampling line 120, a four-way valve 130, an oxygen analyzer 140, and a processor 150.

[0019] The control line 110 is used to obtain flue gas from the exhaust pipe 10. Specifically, the control line 110 extends into a sampling port 11 on the exhaust pipe 10 to obtain the flue gas. The control line 110 may include: a dust removal unit 111, a water removal unit 112, and a control gas sampling pump 113, wherein the dust removal unit 111 is connected to the water removal unit 112, the water removal unit 112 is connected to the control gas sampling pump 113, and the control gas sampling pump 113 is connected to the four-way valve 130. The dust removal unit 111 is used to remove dust from the flue gas, and the water removal unit 112 is used to remove moisture from the flue gas, thereby preventing the subsequent control gas sampling pump 113, the four-way valve 130, and the oxygen analyzer 140 from being contaminated by dust and moisture. It should be noted that, depending on the type of flue gas and requirements, the control line 110 may also include other components. Furthermore, the control line 110 can be made of metal, such as stainless steel. The metal-made control line 110 has high structural strength, preventing it from loosening and leaking due to high-altitude winds or environmental vibrations.

[0020] The sampling line 120 is used to obtain the flue gas in the exhaust pipe 10. Specifically, the sampling line 120 extends into a sampling port 11 on the exhaust pipe 10 to obtain the flue gas. The sampling line 120 may include: a sampling assembly 121, a sampling host 122, and a sampling pump 123, wherein the sampling assembly 121 is connected to the sampling host 122, the sampling host 122 is connected to the sampling pump 123, and the sampling pump 123 is connected to the four-way valve 130. It should be noted that, depending on the type of contaminant to be detected, the sampling assembly 121 may include a suction nozzle, a sampling tube, filter paper, a filter paper holder, a sample transfer tube, a condenser, an impact bottle assembly, or other necessary components. In addition, to avoid contamination of the obtained flue gas sample, the sampling line 120 may be made of glass or Teflon. Furthermore, as shown in Figure 5, the sampling line 120 also includes a protective tube 124 that covers the sampling line 120 to protect it. A control line 110 can be attached to the protective tube 124, whereby both the control line 110 and the sampling line 120 can extend together into the sampling port 11 to obtain the flue gas. The protective tube 124 can be made of metal (e.g., stainless steel).

[0021] The four-way valve 130 connects the control line 110 and the sampling line 120. The four-way valve 130 can switch between the control line 110 and the sampling line 120, allowing either the control line or the sampling line 120 to connect to the oxygen analyzer 140. Specifically, the four-way valve 130 has a first interface 131, a second interface 132, a third interface 133, and a fourth interface 134, wherein the first interface 131 connects to the control line 110, the second interface 132 connects to the oxygen analyzer 140, the third interface 133 connects to the oxygen analyzer 140, and the fourth interface 134 connects to the atmospheric environment. As shown in Figure 3, when the first interface 131 is connected to the second interface 132 and the third interface 133 is connected to the fourth interface 134, the control line 110 will be connected to the oxygen analyzer 140. As shown in Figure 4, if the four-way valve 130 is switched so that the first interface 131 is connected to the fourth interface 134 and the third interface 133 is connected to the second interface 132, then the sampling line 120 will be connected to the oxygen analyzer 140.

[0022] The oxygen analyzer 140 is connected to the four-way valve 130. The oxygen analyzer 140 detects the flue gas from the control line 110 to obtain a first oxygen concentration value and detects the flue gas from the sampling line 120 to obtain a second oxygen concentration value.

[0023] The processor 150 is electrically connected to the oxygen analyzer 140 to compare the first oxygen concentration value with the second oxygen concentration value. A leak in the sampling line 120 is determined when the difference between the first and second oxygen concentration values ​​exceeds a threshold. Specifically, this threshold is between 0.15% and 0.75%. Further explanation: the first oxygen concentration value of the flue gas from the control line 110 can be between 6% and 19%, and the second oxygen concentration value of the flue gas from the sampling line 120 can also be between 6% and 19%. In other words, this embodiment is applicable to flue gas with an oxygen concentration between 6% and 19%, because the oxygen concentration in the air is approximately 21%. Once the sampling line 120 leaks and collects outside air, the second oxygen concentration value (from the flue gas from the sampling line 120) will be greater than the first oxygen concentration value (from the flue gas from the control line 110). In this way, when collecting flue gas samples from the exhaust pipe 10, the first oxygen concentration value and the second oxygen concentration value can be compared in real time to confirm whether the sampling pipeline 120 has leaked.

[0024] Please refer to Figure 6, which is a flowchart of one step of a real-time leak detection method for flue gas sampling according to an embodiment of the present invention. This embodiment provides a real-time leak detection method 200 for flue gas sampling, which includes the following steps:

[0025] Step S210: Use an instant leak detection device for flue gas sampling to sample flue gas in an exhaust pipe.

[0026] Step S220: Switch the four-way valve to connect the control line to the oxygen analyzer.

[0027] Step S230: Obtain the flue gas in the exhaust pipe by comparing it with the pipeline.

[0028] Step S240: Use an oxygen analyzer to detect the flue gas from the control pipeline to obtain a first oxygen concentration value.

[0029] Step S250: Switch the four-way valve to connect the sampling line to the oxygen analyzer.

[0030] Step S260: Obtain the flue gas in the exhaust pipe through the sampling pipeline.

[0031] Step S270: Use an oxygen analyzer to detect the flue gas from the sampling pipeline to obtain a second oxygen concentration value.

[0032] Step S280: The processor compares the first oxygen concentration value with the second oxygen concentration value. If the difference between the first oxygen concentration value and the second oxygen concentration value is greater than a threshold, it is determined that the sampling pipeline is leaking. Specifically, the threshold is between 0.15% and 0.75%, while the first oxygen concentration value of the flue gas from the control pipeline can be between 6% and 19%, and the second oxygen concentration value of the flue gas from the sampling pipeline can be between 6% and 19%.

[0033] Taking the example of a boiler exhaust gas with an oxygen concentration of 6%, if there is a leak in the sampling line (for example, 5% of the ambient air is collected by the sampling line), and the oxygen concentration of the ambient air is 21%, the first oxygen concentration value and the second oxygen concentration value will have the following differences: First oxygen concentration value (flue gas from the control line): 6% Second oxygen concentration value (flue gas from the sampling line): 6% x 0.95 + 21% x 0.05 = 6.75% It can be found that the second oxygen concentration value will be higher than the first oxygen concentration value by 0.75%.

[0034] Taking the example of an incinerator exhaust gas with an oxygen concentration of 11%, if there is a leak in the sampling line (for example, 5% of the ambient air is collected by the sampling line), and the oxygen concentration of the ambient air is 21%, the first oxygen concentration value and the second oxygen concentration value will have the following differences: First oxygen concentration value (flue gas from the control line): 11% Second oxygen concentration value (flue gas from the sampling line): 11% x 0.95 + 21% x 0.05 = 11.5% It can be found that the second oxygen concentration value will be 0.5% higher than the first oxygen concentration value.

[0035] Taking the example of the oxygen concentration of the flue gas from the exhaust pipe of the sintering furnace being 15%, if there is a leak in the sampling pipeline (for example, 5% of the ambient air is collected by the sampling pipeline), and the oxygen concentration of the ambient air is 21%, the first oxygen concentration value and the second oxygen concentration value will have the following differences: First oxygen concentration value (flue gas from the control pipeline): 15% Second oxygen concentration value (flue gas from the sampling pipeline): 15% x 0.95 + 21% x 0.05 = 15.3% It can be found that the second oxygen concentration value will be 0.3% higher than the first oxygen concentration value.

[0036] Taking the example of an exhaust gas with an oxygen concentration of 18%, if there is a leak in the sampling line (for example, 5% of the ambient air is collected by the sampling line), and the oxygen concentration of the ambient air is 21%, the first oxygen concentration value and the second oxygen concentration value will have the following differences: First oxygen concentration value (exhaust gas from the control line): 18% Second oxygen concentration value (exhaust gas from the sampling line): 18% x 0.95 + 21% x 0.05 = 18.15% It can be found that the second oxygen concentration value is 0.15% higher than the first oxygen concentration value.

[0037] Through the above examples, the embodiments of the present invention can effectively and instantly confirm whether a sampling pipeline has leaked by comparing the difference between the first oxygen concentration value and the second oxygen concentration value.

[0038] As described above, the control line and the sampling line can simultaneously acquire flue gas from the exhaust pipe. By switching the four-way valve, the oxygen analyzer can detect the first oxygen concentration value of the flue gas from the control line and the second oxygen concentration value of the flue gas from the sampling line. By comparing the first oxygen concentration value with the second oxygen concentration value, it can be confirmed whether the sampling line is leaking. This solves the problem in the prior art that it is necessary to wait until sampling to determine whether the sampling line is leaking, and it can also be confirmed immediately whether the sampling line is leaking. Once the sampling line leaks, the operator can immediately stop sampling and confirm the leak point of the sampling line. [Simplified Explanation of the Diagram]

[0039] Figures 1A and 1B are schematic diagrams of existing flue gas sampling techniques acquiring flue gas samples at different depths. Figure 2 is a schematic diagram of existing flue gas sampling techniques acquiring flue gas samples at different sampling holes. Figure 3 is a schematic diagram of a control line of a real-time leak detection device for flue gas sampling according to an embodiment of the present invention connected to an oxygen analyzer. Figure 4 is a schematic diagram of a sampling line of a real-time leak detection device for flue gas sampling according to an embodiment of the present invention connected to an oxygen analyzer. Figure 5 is a cross-sectional schematic diagram of the control line and the sampling line in an embodiment of the present invention. Figure 6 is a flowchart of a step of a real-time leak detection method for flue gas sampling according to an embodiment of the present invention.

Claims

1. An instant leak detection device for flue gas sampling, installed on an exhaust pipe, comprising: a control line disposed on a sampling port of the exhaust pipe for acquiring flue gas in the exhaust pipe; a sampling line disposed on the sampling port of the exhaust pipe for acquiring the flue gas in the exhaust pipe; a four-way valve connected to the control line and the sampling line; an oxygen analyzer connected to the four-way valve, the oxygen analyzer detecting the flue gas from the control line to obtain a first oxygen concentration value and detecting the flue gas from the sampling line to obtain a second oxygen concentration value; and a processor electrically connected to the oxygen analyzer to compare the first oxygen concentration value with the second oxygen concentration value, wherein when the difference between the first oxygen concentration value and the second oxygen concentration value is greater than a threshold, a leak is determined in the sampling line.

2. The instant leak detection device for flue gas sampling as described in claim 1, wherein the threshold is between 0.15% and 0.75%.

3. The instant leak detection device for flue gas sampling as described in claim 2, wherein the first oxygen concentration value of the flue gas from the control line is between 6% and 19%, and the second oxygen concentration value of the flue gas from the sampling line is between 6% and 19%.

4. The real-time leak detection device for flue gas sampling as described in claim 1, wherein the control line comprises: a dust removal unit, a water removal unit and a control gas sampling pump.

5. The real-time leak detection device for flue gas sampling as described in claim 1, wherein the sampling line comprises: a sampling component, a sampling host, and a sampling pump.

6. The instant leak detection device for flue gas sampling as described in claim 1, wherein the control line is made of metal.

7. The instant leak detection device for flue gas sampling as described in claim 1, wherein the sampling line is made of glass or Teflon.

8. A real-time leak detection method for flue gas sampling, comprising the following steps: sampling flue gas in an exhaust pipe using a flue gas sampling leak detection device as described in claim 1, wherein a control line and the sampling line are together installed on the sampling port of the exhaust pipe; switching the four-way valve to connect the control line to an oxygen analyzer; acquiring the flue gas in the exhaust pipe through the control line; detecting the flue gas from the control line using the oxygen analyzer to obtain a first oxygen concentration value; switching the four-way valve to connect the sampling line to the oxygen analyzer; acquiring the flue gas in the exhaust pipe through the sampling line; detecting the flue gas from the sampling line using the oxygen analyzer to obtain a second oxygen concentration value; and comparing the first oxygen concentration value with the second oxygen concentration value using a processor, wherein if the difference between the first oxygen concentration value and the second oxygen concentration value is greater than a threshold, a leak is determined in the sampling line.

9. The instant leak detection method for flue gas sampling as described in claim 8, wherein the threshold is between 0.15% and 0.75%.

10. The instantaneous leak detection method for flue gas sampling as described in claim 9, wherein the first oxygen concentration value of the flue gas from the control line is between 6% and 19%, and the second oxygen concentration value of the flue gas from the sampling line is between 6% and 19%.

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