A long-size high-temperature flue gas test sampling probe

Abstract

The utility model relates to a long size high temperature flue gas test sampling probe, include: sampling probe outer layer pipeline, be equipped with sampling probe internal isolation layer pipeline in sampling probe outer layer pipeline, be equipped with sampling probe central pipeline in sampling probe internal isolation layer pipeline, be equipped with temperature test thermocouple in sampling probe central pipeline, sampling probe outer layer pipeline, sampling probe internal isolation layer pipeline, sampling probe central pipeline, sampling probe outer layer pipeline is connected with cooling water import pipeline. The utility model discloses long pipe, so that sampling probe can directly explore to the hearth flame center, and effectively covers the test point on the whole section of hearth. Because length is longer, can adjust test position and test point number according to the depth of inserting into the hearth, and flexible. In order to prevent the test sampling probe from melting or deforming at high temperature, the test sampling probe adopts three-layer sleeve pipe, forms two circulating water jackets, and the probe is cooled with cold water to prevent high-temperature deformation or damage.

Description

Technical Field

[0001] This utility model relates to a long-length high-temperature flue gas testing and sampling probe, which is an environmental protection testing device used for testing boilers in combustion operation. Background Technology

[0002] Increasingly stringent pollutant emission standards require a reduction in combustion pollutant emissions from coal-fired boilers. Only by optimizing in-furnace combustion conditions can the amount of pollutants be effectively controlled. Furthermore, optimizing combustion conditions can also reasonably reduce fuel consumption and prevent boiler coking, tube rupture, and other problems. As one of the combustion optimization measures, significant work has been done in recent years in areas such as burner modification, playing a crucial role in improving the combustion conditions of power plant boilers. However, due to the large furnace size and high flame temperature of large coal-fired boilers, research on in-furnace combustion testing techniques for assessing combustion conditions has encountered numerous problems, highlighting a weakness in practical measurement methods. Therefore, how to solve the problem of measuring actual temperature and pollutants under the conditions of high furnace temperature and large size in large coal-fired boilers is an issue that needs to be addressed. Summary of the Invention

[0003] To overcome the problems of existing technologies, this utility model proposes a long-size high-temperature flue gas testing and sampling probe. The probe uses water circulation cooling to solve the problems of high temperature and long size sampling, and is used for testing the actual temperature of the furnace flame and pollutants in large boilers, thereby improving the accuracy of testing boiler combustion conditions.

[0004] The purpose of this utility model is achieved as follows: A long-length high-temperature flue gas testing sampling probe includes: an outer sampling probe pipe with its front end inserted into the combustion furnace and its rear end placed outside the combustion furnace as a shell; an inner sampling probe isolation layer pipe is provided inside the outer sampling probe pipe; a central sampling probe pipe is provided inside the inner sampling probe isolation layer pipe; a temperature testing thermocouple is provided in the central sampling probe pipe; the length of the outer sampling probe pipe, the inner sampling probe isolation layer pipe, and the central sampling probe pipe exceeds 10 meters; the front and rear ends of the outer sampling probe pipe and the inner sampling probe isolation layer pipe are sealed. The sampling probe is closed; the outer pipe of the sampling probe is connected to the cooling water inlet pipe, and the inner isolation layer pipe of the sampling probe is connected to the cooling water outlet pipe. The inner isolation layer pipe of the sampling probe is provided with connecting holes that allow water to flow from the outer pipe of the sampling probe into the inner isolation layer pipe of the sampling probe. The connecting holes are evenly distributed around the outer circumference of the front end of the inner isolation layer pipe, with a diameter of not less than φ8mm. The sum of the cross-sectional areas of all connecting holes is 1.5 to 2.5 times the cross-sectional area of ​​the inlet pipe. The front end of the central pipe of the sampling probe is open, the rear end is closed, and it is connected to the flue gas sampling pipe. The flue gas sampling pipe is connected to the flue gas measurement facility.

[0005] Furthermore, the outer pipe of the sampling probe, the inner isolation layer pipe of the sampling probe, and the central pipe of the sampling probe are three circular cross-section pipes of different diameters, with their rotation center axes coaxial, forming a jacket structure.

[0006] Furthermore, the sampling probe's central pipe is equipped with a filter sleeve at its front end.

[0007] Furthermore, the filter sleeve is threadedly connected to the front end of the central pipe of the sampling probe.

[0008] Furthermore, the outer pipe of the sampling probe, the inner isolation layer pipe of the sampling probe, the central pipe of the sampling probe, and the filter sleeve are made of high-temperature resistant alloy steel.

[0009] Furthermore, the flue gas measurement facility includes: a flue gas sampling pump and a Venturi extraction device.

[0010] The advantages and beneficial effects of this utility model are as follows: This utility model uses a long tube so that the sampling probe can directly reach the center of the furnace flame, effectively covering the test points on the entire cross-section of the furnace. Due to its long length, the test position and number of test points can be adjusted according to the insertion depth into the furnace, offering flexibility. To prevent the test sampling probe from melting or deforming at high temperatures, the test sampling probe adopts a three-layer sleeve, forming two layers of circulating water jackets, using cold water to cool the probe, and uses a high-temperature resistant alloy steel pipe to prevent high-temperature deformation or damage. Attached Figure Description

[0011] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0012] Figure 1 This is a schematic diagram of the sampling probe described in embodiments one, two, three, and six of this utility model. Detailed Implementation

[0013] Example 1: This embodiment is a long-sized high-temperature flue gas testing and sampling probe, such as... Figure 1As shown. This embodiment includes: an outer pipe 1 for a sampling probe, with its front end inserted into the combustion chamber and its rear end placed outside the combustion chamber as a shell; an inner isolation layer pipe 2 for the sampling probe is provided inside the outer pipe; a central pipe 3 for the sampling probe is provided inside the inner isolation layer pipe; a temperature testing thermocouple 4 is provided inside the central pipe; the lengths of the outer pipe, the inner isolation layer pipe, and the central pipe are 10-15 meters; the front and rear ends of the outer pipe and the inner isolation layer pipe are sealed. The outer pipe of the sampling probe is connected to the cooling water inlet pipe 101, and the inner isolation layer pipe of the sampling probe is connected to the cooling water outlet pipe 201. The inner isolation layer pipe of the sampling probe has connecting holes 202 that allow water to flow from the outer pipe into the inner isolation layer pipe. The size and number of connecting holes 202 are designed to meet the maximum water flow rate. Holes no smaller than φ8mm are opened at the front end of the inner isolation layer pipe 2, and the holes are arranged in a circumferential pattern. The number and area of ​​the holes are between 1.5 and 2.5 times the cross-sectional area of ​​the outer inlet pipe. This ensures the cooling water flow rate and uniformity.

[0014] The sampling probe's central pipe is open at the front end and closed at the rear end, and is connected to the flue gas sampling pipe 5, which is connected to the flue gas measuring facility 6.

[0015] A thermocouple of sufficient length as the sampling probe is inserted into the central tube of the sampling probe, and the thermocouple is sealed and fixed to the end (cold junction) of the sampling probe using an expansion ring. The expansion ring is fitted onto the thermocouple and then threaded to the end of the probe. Because the thermocouple is of sufficient length and its tip passes through the front end of the sampling probe, the heat-sensitive part of the thermocouple is entirely within the temperature measurement area, thus ensuring the accuracy of the measured temperature.

[0016] The sampling probe described in this embodiment is an instrument used for sampling and measuring temperature and flue gas in large boiler furnaces. "Large" refers to a furnace several meters in size with high internal temperatures (1500℃-1600℃), ensuring the authenticity and accuracy of the test under such harsh conditions. The "length" of the flue gas testing sampling probe indicates a length exceeding 10 meters, typically reaching 12-15 meters, to allow the probe to directly reach the center of the furnace flame and effectively cover the entire cross-section of the furnace for testing. Due to its long length, the testing position and number of testing points can be adjusted according to the insertion depth within the furnace, offering flexibility. To prevent the testing sampling probe from melting or deforming at high temperatures, it is cooled by circulating cooling water and uses high-temperature resistant alloy steel tubing to prevent deformation or damage at high temperatures.

[0017] The main structure of the probe consists of two layers of water jackets surrounding the central pipe of the sampling probe. The water jackets can resist external heat as well as the hot airflow drawn by the sampling tube.

[0018] The sampling probe's outer pipe, inner isolation layer pipe, and central pipe can be designed as three concentric circles with a coaxial center. The outer and inner isolation layer pipes are sealed at both ends, with a water flow channel (connecting hole) between them. Inlet and outlet pipes are provided on the sides of the pipes to form a cooling water flow channel. Figure 1 The flow direction is indicated by the middle arrow. The flow rate and velocity of the cooling water inside the cooling sleeve are adjusted by the regulating valve at the external cooling water inlet. If the return water temperature is high, the inlet flow rate is increased; if the return water temperature is low, no adjustment of the inlet flow rate is necessary. This ensures the cooling of the sampling device and prevents overheating, burning, or deformation damage. To prevent blockage of the flue gas sampling probe and protect the thermocouple, a removable sleeve and filter can be installed at the probe tip.

[0019] In order to extract the flue gas from the furnace, a Venturi extraction device is used to draw the gas to the end of the sampling probe, and then the gas is drawn into the flue gas analyzer for sampling and analysis by a sampling extraction pump.

[0020] For the venturi device and the extraction pump to extract the test flue gas, the extraction pressure must be greater than the furnace negative pressure and the resistance of the sampling probe. Therefore, the extraction pressure of both is generally adjusted according to the negative pressure of each test furnace. The venturi device pressure range is between 0.25MPa and 0.5MPa, and the extraction pump pressure is between 2KPa and 3KPa negative pressure to meet the sampling requirements.

[0021] Example 2: This embodiment is an improvement upon Embodiment 1, detailing the outer sampling probe pipe, the inner isolation layer pipe, and the central sampling probe pipe. In this embodiment, the outer sampling probe pipe, the inner isolation layer pipe, and the central sampling probe pipe are three circular cross-section pipes of different diameters, with their rotational axes coaxial, forming a jacketed structure.

[0022] The sampling probe is made of three high-temperature resistant alloy steel pipes of different lengths and diameters, forming a jacket structure (e.g.) Figure 1 As shown, these serve as the outer pipe of the sampling probe, the inner isolation layer pipe of the sampling probe, and the central pipe of the sampling probe, respectively, to ensure smooth flow of cooling water and effectively cool the sampling probe in high-temperature environments, preventing the sampling probe from burning or deforming.

[0023] Example 3: This embodiment is an improvement upon the above embodiment, detailing the central conduit of the sampling probe. In this embodiment, the front end of the central conduit of the sampling probe is equipped with a filter sleeve 301, see [link to relevant documentation]. Figure 1 .

[0024] To prevent dust in the high-temperature flue gas from clogging the sampling pipe and affecting the flue gas sampling data, this embodiment features a filter sleeve at the front end of the flue gas sampling probe. This effectively protects the thermocouple at the probe front end and prevents dust from clogging the probe. For easy disassembly and replacement of the filter sleeve, the probe front end and the filter sleeve can be connected by threads.

[0025] Example 4: This embodiment is an improvement on the above embodiment, and is a refinement of the filter sleeve in the above embodiment.

[0026] To facilitate disassembly, cleaning, or replacement of the filter sleeve at the front end of the sampling probe, the filter sleeve is connected to the front end of the sampling probe by a threaded connection.

[0027] Example 5: This embodiment is an improvement upon the above embodiment, detailing the outer sampling probe pipe, the inner isolation layer pipe, the central sampling probe pipe, and the filter sleeve. The materials used for the outer sampling probe pipe, the inner isolation layer pipe, the central sampling probe pipe, and the filter sleeve in this embodiment are high-temperature resistant alloy steels, such as 310SS and 304.

[0028] Example 6: This embodiment is an improvement upon the above embodiment, detailing the flue gas measurement facility. The flue gas measurement facility described in this embodiment includes: a flue gas sampling pump 601 and a flue gas analyzer, as well as a Venturi extraction device 602, see [link to documentation]. Figure 1 .

[0029] The flue gas sampling probe is equipped with a Venturi extractor to extract the flue gas. At the end of the sampling probe (before the flue gas enters the Venturi extractor), a vacuum pump is used to extract the flue gas and transport it into the flue gas sampling cylinder. Then, the flue gas is tested and analyzed for its components.

[0030] Finally, it should be noted that the above is only used to illustrate the technical solution of this utility model and not to limit it. Although this utility model has been described in detail with reference to the preferred arrangement, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model (such as the form of the combustion furnace, the cross-sectional shape of the connecting pipe and various instruments for measuring flue gas, etc.) without departing from the spirit and scope of the technical solution of this utility model.

Claims

1. A long-length high-temperature flue gas testing and sampling probe, characterized in that, include: A sampling probe consists of an outer pipe, with its front end inserted into the combustion furnace and its rear end positioned outside as a shell. Inside the outer pipe is an internal isolation layer pipe, and within that is a central pipe. A temperature thermocouple is located within the central pipe. The total length of the outer, internal, and central pipes exceeds 10 meters. Both ends of the outer and internal isolation pipes are sealed. The outer pipe is connected to cooling water. The sampling probe is connected to the cooling water outlet pipe via an inlet pipe. The inner isolation layer pipe of the sampling probe has connecting holes that allow water to flow from the outer pipe of the sampling probe into the inner isolation layer pipe. These connecting holes are evenly distributed around the outer circumference of the front end of the inner isolation layer pipe, with a diameter greater than φ8mm. The sum of the cross-sectional areas of all connecting holes is 1.5 to 2.5 times the cross-sectional area of ​​the inlet pipe. The central pipe of the sampling probe is open at the front end and closed at the rear end, and is connected to a flue gas sampling pipe, which is connected to a flue gas measurement facility.

2. The sampling probe according to claim 1, characterized in that, The outer pipe of the sampling probe, the inner isolation layer pipe of the sampling probe, and the central pipe of the sampling probe are three jacketed structures with different diameters and circular cross-sections, and their rotation center axes are coaxial.

3. The sampling probe according to claim 2, characterized in that, The sampling probe has a filter sleeve at the front end of the central pipe.

4. The sampling probe according to claim 3, characterized in that, The filter sleeve is threadedly connected to the front end of the central pipe of the sampling probe.

5. The sampling probe according to claim 4, characterized in that, The outer pipe of the sampling probe, the inner isolation layer pipe of the sampling probe, the central pipe of the sampling probe, and the filter sleeve are made of high-temperature resistant alloy steel.

6. The sampling probe according to claim 5, characterized in that, The flue gas measurement facility includes a flue gas sampling pump and a Venturi extraction device.

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