Anti-abrasion protection method for bed temperature measuring point of circulating fluidized bed boiler

Abstract

The invention discloses an anti-wear protection method for a bed temperature measuring point of a circulating fluidized bed boiler, relates to the technical field of circulating fluidized bed boilers, and aims to solve the problems that in the prior art, after a wear-resistant sleeve of a thermocouple is damaged, the bed temperature measuring point cannot be used, the bed temperature of the boiler cannot be monitored, and boiler accidents are easily caused. Comprising the following steps: 1, determining the specific position of a bed temperature measuring point of the circulating fluidized bed boiler and the length of a thermocouple extending into a boiler wall; 2, according to the positions of different bed temperature measuring points, designing and respectively manufacturing a corresponding wear-resistant sleeve, an inner protective sleeve and an outer protective sleeve; 3, if the bed temperature measuring point is on the side surface of the boiler wall, inserting the thermocouple from the side surface of the boiler wall, and arranging a wear-resistant sleeve on the outer side of the part, inserted into the boiler wall, of the thermocouple for protection; 4, if the bed temperature measuring point is located at the bottom of the boiler wall, the thermocouple is inserted from the bottom of the boiler wall, and an inner protective sleeve and an outer protective sleeve are adopted for protection.

Description

Technical Field

[0001] The invention relates to the technical field of circulating fluidized bed boilers, in particular to an anti-wear protection method for bed temperature measuring points of a circulating fluidized bed boiler. Background Art

[0002] The circulating fluidized bed boiler uses the most industrialized clean coal combustion technology. The circulating fluidized bed boiler uses fluidized combustion. The main structure includes two parts: the combustion chamber and the circulating return furnace. The biggest difference from the bubbling fluidized bed combustion technology is the high operating wind speed, which strengthens the heterogeneous reaction processes such as combustion and desulfurization. The boiler capacity can be expanded to a large capacity acceptable to the power industry. The circulating fluidized bed boiler has well solved the basic problems of thermodynamics, mechanics, materials science, and engineering problems such as expansion, wear, and overtemperature, and has become an advanced technology for the utilization of flame-retardant solid fuel energy. The bed temperature and return material temperature measurement points of the circulating fluidized bed boiler directly affect the stability of the boiler operation. At present, the bed temperature measurement points of the circulating fluidized bed boiler use wear-resistant thermocouples to protect the bed temperature measurement points; For example, the authorized patent with announcement number CN208011699U (a wear protection device for a circulating fluidized bed bed temperature measurement point): a wear-resistant thermocouple is installed at the bed temperature measurement point, the wear protection device is installed on the furnace wall below the wear-resistant thermocouple, and the cross section of the side surface is triangular, the upper side surface of the wear protection device is inclined downward and forms an acute angle with the horizontal plane, and the lower side surface is inclined upward and forms an acute angle with the horizontal plane; Although the above-mentioned prior art changes the flow mode of primary flue gas and slows down the flow speed, effectively slowing down the wear of the temperature measuring probe, it does not have a structure to improve the wear resistance of the thermocouple at the bed temperature measuring point. In the long-term operation process, the thermocouple installed at the bed temperature measuring point on the side of the furnace wall will not only be worn at the top, but also wear at the junction of the thermocouple and the furnace wall due to the influence of the flue gas vortex inside the boiler. The degree of wear is often higher than the wear on the top of the thermocouple, and the wear of the thermocouple installed at the bed temperature measuring point at the bottom of the furnace wall is mainly concentrated on the junction surface between the thermocouple and the bottom of the furnace wall. As a result, when the wear-resistant sleeve of the thermocouple is damaged, the bed temperature measuring point cannot be used, the boiler cannot monitor the bed temperature, and boiler accidents are easily caused. Therefore, the market urgently needs to develop a wear-proof protection method for the bed temperature measuring point of a circulating fluidized bed boiler to help people solve the existing problems. Summary of the invention

[0003] The purpose of the present invention is to provide a method for anti-wear protection of bed temperature measuring points of a circulating fluidized bed boiler, so as to solve the problem proposed in the above background technology that after the wear-resistant sleeve of the thermocouple is damaged, the bed temperature measuring point cannot be used, the boiler cannot monitor the bed temperature, and boiler accidents may occur.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for anti-wear protection of bed temperature measuring points of a circulating fluidized bed boiler, comprising the following steps: Step 1: First determine the specific location of the circulating fluidized bed boiler bed temperature measurement point and the length of the thermocouple extending into the boiler furnace wall; Step 2: According to the positions of different bed temperature measuring points, design and manufacture corresponding wear-resistant casings, inner protective casings and outer protective casings; Step 3: If the bed temperature measuring point is on the side of the boiler furnace wall, the thermocouple is inserted from the side of the boiler furnace wall, and a wear-resistant sleeve is set outside the part where the thermocouple is inserted into the boiler furnace wall for protection. The wear-resistant sleeve covers the joint part between the thermocouple and the furnace wall; Step 4: If the bed temperature measuring point is at the bottom of the boiler furnace wall, the thermocouple is inserted from the bottom of the boiler furnace wall and protected by an inner protective sleeve and an outer protective sleeve; Step 5: After installation, debug the anti-wear protection structure to ensure that the bed temperature measuring point works normally, and conduct regular inspection and maintenance during boiler operation; Wherein, when the bed temperature measuring point is on the side of the boiler furnace wall, a mounting sleeve is provided on one side of the bed temperature measuring point, the thermocouple passes through the mounting sleeve into the interior of the boiler furnace wall, and the wear-resistant sleeve is provided on the outside of one end of the thermocouple and is welded to the mounting sleeve; When the bed temperature measuring point is at the bottom of the side of the boiler furnace wall, an installation sleeve is arranged below the bed temperature measuring point, and the thermocouple penetrates into the interior of the boiler furnace wall through the installation sleeve. The inner protective sleeve is arranged on the outside of one end of the thermocouple and is welded to the installation sleeve, and the outer protective sleeve is arranged on the outside of the inner protective sleeve.

[0005] Preferably, the inner diameter of the wear-resistant sleeve is 10 mm larger than the outer diameter of the thermocouple, and the wall thickness of the wear-resistant sleeve is 3.5 mm.

[0006] Preferably, the wear-resistant sleeve is made of 253MA stainless steel which is resistant to high temperature, wear and corrosion.

[0007] Preferably, the length of the inner protective sleeve matches the length of the thermocouple extending into the interior of the boiler furnace wall.

[0008] Preferably, the inner diameter of the inner protective sleeve is 10 mm larger than the outer diameter of the thermocouple, and the wall thickness of the wear-resistant sleeve is 3.5 mm.

[0009] Preferably, the inner protective sleeve is made of 253MA stainless steel which is resistant to high temperature, wear and corrosion.

[0010] Preferably, the outer diameter of the outer protective sleeve is 4 mm larger than the outer diameter of the inner protective sleeve, and the wall thickness of the outer protective sleeve is 4 mm.

[0011] Preferably, the outer protective sleeve is made of 253MA stainless steel which is resistant to high temperature, wear and corrosion.

[0012] Preferably, when the bed temperature measuring point is at the bottom of the boiler furnace wall, the length of the thermocouple extending into the interior of the boiler furnace wall is greater than 500 mm.

[0013] Preferably, before installing the anti-wear protection structure at the boiler furnace wall bed temperature measuring point, the corresponding position of the boiler furnace wall is pretreated, and the pretreatment includes cleaning, rust removal and coating of anti-corrosion coating to improve the bonding strength and service life of the anti-wear protection structure and the boiler furnace wall.

[0014] Compared with the prior art, the present invention has the following beneficial effects: During the operation of the circulating fluidized bed boiler, when the bed temperature measuring point is located on the side of the boiler furnace wall, the invention uses a combination of an installation sleeve and a wear-resistant sleeve, which not only achieves a stable installation of the thermocouple, but also greatly reduces the wear caused by side airflow scouring, solid particle impact, etc., ensuring the continuity and accuracy of the temperature measurement data; for the bottom bed temperature measuring point, a double sleeve protection system is adopted. The inner protective sleeve wraps the thermocouple to isolate it from high temperature and direct impact, and the outer protective sleeve further enhances the stability and durability of the overall structure, effectively preventing damage caused by factors such as bottom high temperature and ash accumulation, ensuring the long-term stable operation of the bed temperature measuring point, providing a solid guarantee for the stable operation of the boiler, reducing the number of shutdowns and maintenance due to thermocouple wear, and improving the availability and economic benefits of the boiler.

[0015] The invention adopts high temperature resistant, wear resistant and corrosion resistant 253MA stainless steel as the sleeve material for the wear-resistant sleeve, inner protective sleeve and outer protective sleeve, ensuring that the wear-resistant protection structure can work stably for a long time in the extremely harsh environment inside the boiler, and effectively resist adverse factors such as high temperature, fly ash impact and chemical corrosion. At the same time, the inner diameter of the wear-resistant sleeve and the inner protective sleeve is larger than the outer diameter of the thermocouple, which not only ensures the flexibility and temperature measurement accuracy of the thermocouple, but also enhances the wear resistance of the sleeve. The precise matching of the inner protective sleeve and the thermocouple extension length, as well as the appropriate increase in the outer diameter of the outer protective sleeve and the selection of wall thickness, further enhance the stability and protection effect of the overall structure, significantly extend the service life of the thermocouple and other related components of the boiler, reduce maintenance costs, and improve the economy and reliability of boiler operation.

[0016] This invention controls the length of the thermocouple extending into the boiler furnace wall when the bed temperature measuring point is at the bottom of the boiler furnace wall. The longer thermocouple insertion depth enables the thermocouple to more directly contact the actual temperature inside the furnace, reducing the temperature measurement error caused by factors such as the temperature difference between the inside and outside of the furnace and airflow disturbance. At the same time, the combined protection of the inner and outer protective sleeves effectively prevents the performance degradation or failure of the thermocouple due to wear, corrosion and other reasons, ensuring the continuity and stability of the temperature measurement data, which is conducive to real-time and accurate reflection of the temperature conditions in the furnace, providing a reliable basis for the combustion adjustment and load control of the boiler, thereby improving the overall operating efficiency and performance of the boiler.

[0017] The invention can improve the bonding strength and service life of the anti-wear protection structure and the boiler furnace wall by pre-treating the corresponding position of the boiler furnace wall at the bed temperature measuring point of the boiler furnace wall before installing the anti-wear protection structure, including cleaning, rust removal and coating of anti-corrosion coating. Cleaning and rust removal can remove impurities and rust layer on the surface of the furnace wall and improve the adhesion of the anti-wear protection structure during installation. Coating of anti-corrosion coating further enhances the corrosion resistance of the furnace wall surface and prevents the reduction of bonding strength due to corrosion, ensuring that the anti-wear protection structure can be firmly installed on the boiler furnace wall and maintain a stable bonding state even during long-term operation of the boiler. It not only extends the service life of the anti-wear protection structure itself, but also indirectly improves the overall durability of the boiler furnace wall and reduces the maintenance and replacement costs caused by damage to the furnace wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the thermocouple of the present invention being inserted from the side of the boiler furnace wall; Figure 2 A schematic diagram of the thermocouple of the present invention being inserted from the bottom of a boiler furnace wall; Figure 3 It is an enlarged schematic diagram of the A part of the present invention; In the figure: 1. Boiler wall; 2. Thermocouple; 3. Installation sleeve; 4. Wear-resistant sleeve; 5. Inner protective sleeve; 6. Outer protective sleeve. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0020] See also Figure 1-3 , an embodiment provided by the present invention: a method for anti-wear protection of bed temperature measuring points of a circulating fluidized bed boiler, comprising the following steps: Step 1: first determine the specific location of the circulating fluidized bed boiler bed temperature measurement point and the length of the thermocouple 2 extending into the boiler furnace wall 1; By determining the specific location of the circulating fluidized bed boiler bed temperature measuring point and the length of the thermocouple 2 extending into the boiler furnace wall 1, an accurate data basis is provided for the subsequent design of the anti-wear protection structure, which is conducive to the anti-wear protection structure to accurately cover the easily worn area, improve the pertinence and effectiveness of the protection, thereby extending the service life of the bed temperature measuring point and reducing the replacement and maintenance costs caused by wear; Step 2: Design and manufacture the corresponding wear-resistant casing 4, inner protective casing 5 and outer protective casing 6 according to the positions of different bed temperature measuring points; According to the location and environmental conditions of different bed temperature measurement points, corresponding sleeves are designed and manufactured respectively to achieve customized protection. This differentiated design can better adapt to the wear characteristics of different positions and improve the overall performance of the anti-wear protection structure. At the same time, customized production also ensures the rational use of materials and reduces production costs. Step 3: If the bed temperature measuring point is on the side of the boiler furnace wall 1, the thermocouple 2 is inserted from the side of the boiler furnace wall 1, and a wear-resistant sleeve 4 is provided outside the portion where the thermocouple 2 is inserted into the boiler furnace wall 1 for protection, and the wear-resistant sleeve 4 covers the junction between the thermocouple 2 and the furnace wall; For the bed temperature measuring point on the side of the furnace wall, a wear-resistant sleeve is provided outside the part where the thermocouple 2 is inserted into the boiler furnace wall 1 for protection. In particular, the wear-resistant sleeve 4 covers the junction between the thermocouple and the furnace wall, which can effectively resist eddy current wear, not only protecting the top of the thermocouple from direct erosion, but also solving the wear problem of the junction caused by eddy current, and significantly improving the protection effect; Step 4: If the bed temperature measurement point is at the bottom of the boiler furnace wall 1, the thermocouple 2 is inserted from the bottom of the boiler furnace wall 1 and protected by the inner protective sleeve 5 and the outer protective sleeve 6; For the bed temperature measuring point at the bottom of the furnace wall, the inner protective sleeve 5 and the outer protective sleeve 6 are used for double protection, which enhances the stability and durability of the protection structure. The setting of the inner protective sleeve 5 prevents the thermocouple 2 from being directly impacted by solid particles, and the setting of the outer protective sleeve 6 can further resist the erosion of the external environment, ensuring the long-term stable operation of the thermocouple 2; Step 5: After installation, debug the anti-wear protection structure to ensure that the bed temperature measuring point works normally, and conduct regular inspection and maintenance during boiler operation; It is convenient to find and deal with potential problems in a timely manner, avoiding damage to bed temperature measurement points and boiler accidents caused by failure of protection structures, and improving boiler safety and operating efficiency; When the bed temperature measuring point is located on the side of the boiler furnace wall 1, a mounting sleeve 3 is provided on one side of the bed temperature measuring point, and the thermocouple 2 penetrates into the interior of the boiler furnace wall 1 through the mounting sleeve 3. The wear-resistant sleeve 4 is provided on the outside of one end of the thermocouple 2 and is welded to the mounting sleeve 3. When the bed temperature measuring point is at the bottom of the side of the boiler furnace wall 1, a mounting sleeve 3 is arranged below the bed temperature measuring point, and the thermocouple 2 penetrates into the interior of the boiler furnace wall 1 through the mounting sleeve 3. The inner protective sleeve 5 is arranged on the outside of one end of the thermocouple 2 and is welded to the mounting sleeve 3. The outer protective sleeve 6 is arranged on the outside of the inner protective sleeve 5. The thermocouple 2 adopts a wear-resistant thermocouple.

[0021] Furthermore, the inner diameter of the wear-resistant sleeve 4 is 10 mm larger than the outer diameter of the thermocouple 2, providing sufficient space for the thermocouple 2 to avoid direct contact wear, and the wall thickness of the wear-resistant sleeve 4 is 3.5 mm, which enhances the wear resistance of the wear-resistant sleeve 4 and extends its service life.

[0022] Furthermore, the wear-resistant sleeve 4 is made of 253MA stainless steel that is resistant to high temperature, wear and corrosion, ensuring the stability and reliability of the wear-resistant sleeve 4 in high temperature, high pressure and corrosive environments.

[0023] Furthermore, the length of the inner protective sleeve 5 matches the length of the thermocouple 2 extending into the interior of the boiler furnace wall 1 , ensuring that the inner protective sleeve 5 can completely cover the easily worn area of ​​the thermocouple 2 .

[0024] Furthermore, the inner diameter of the inner protective sleeve 5 is 10 mm larger than the outer diameter of the thermocouple 2, providing sufficient space for the thermocouple 2 to avoid direct contact wear, and the wall thickness of the wear-resistant sleeve 4 is 3.5 mm, which enhances the wear resistance of the inner protective sleeve 5 and extends its service life.

[0025] Furthermore, the inner protective sleeve 5 is made of 253MA stainless steel that is resistant to high temperature, wear and corrosion, thereby ensuring the stability and reliability of the inner protective sleeve 5 in high temperature, high pressure and corrosive environments.

[0026] Furthermore, the outer diameter of the outer protective sleeve 6 is 4 mm larger than the outer diameter of the inner protective sleeve 5, and the wall thickness of the outer protective sleeve 6 is 4 mm. The outer protective sleeve 6 is directly sleeved on the outside of the inner protective sleeve 5 by its own weight. The inner protective sleeve 5 and the outer protective sleeve 6 cooperate with each other to form a more solid protective barrier.

[0027] Furthermore, the outer protective sleeve 6 is made of 253MA stainless steel that is resistant to high temperature, wear and corrosion, thereby ensuring the stability and reliability of the outer protective sleeve 6 in high temperature, high pressure and corrosive environments.

[0028] Furthermore, when the bed temperature measuring point is at the bottom of the boiler furnace wall 1, the length of the thermocouple 2 extending into the boiler furnace wall 1 is greater than 500 mm. The longer insertion depth can keep the sensitive part of the thermocouple away from the direct scouring area in the furnace, thereby reducing wear and extending service life.

[0029] Furthermore, before the anti-wear protection structure of the bed temperature measuring point of the boiler furnace wall 1 is installed, the corresponding position of the boiler furnace wall 1 is pretreated, and the pretreatment includes cleaning, rust removal and coating of anti-corrosion coating, so as to improve the bonding strength and service life of the anti-wear protection structure and the boiler furnace wall 1, and reduce the loosening and falling off problems caused by weak bonding.

[0030] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for anti-wear protection of bed temperature measuring points of a circulating fluidized bed boiler, characterized in that: The following steps are involved: Step 1: first determine the specific location of the circulating fluidized bed boiler bed temperature measurement point and the length of the thermocouple (2) extending into the boiler furnace wall (1); Step 2: designing and manufacturing corresponding wear-resistant sleeves (4), inner protective sleeves (5) and outer protective sleeves (6) according to the positions of different bed temperature measuring points; Step 3: If the bed temperature measuring point is on the side of the boiler furnace wall (1), the thermocouple (2) is inserted from the side of the boiler furnace wall (1), and a wear-resistant sleeve (4) is provided outside the portion where the thermocouple (2) is inserted into the boiler furnace wall (1) for protection, and the wear-resistant sleeve (4) covers the junction between the thermocouple (2) and the furnace wall; Step 4: If the bed temperature measurement point is at the bottom of the boiler furnace wall (1), the thermocouple (2) is inserted from the bottom of the boiler furnace wall (1) and protected by an inner protective sleeve (5) and an outer protective sleeve (6); Step 5: After installation, debug the anti-wear protection structure to ensure that the bed temperature measuring point works normally, and conduct regular inspection and maintenance during boiler operation; When the bed temperature measuring point is located on the side of the boiler furnace wall (1), a mounting sleeve (3) is provided on one side of the bed temperature measuring point, the thermocouple (2) passes through the mounting sleeve (3) into the interior of the boiler furnace wall (1), and the wear-resistant sleeve (4) is provided on the outside of one end of the thermocouple (2) and is welded to the mounting sleeve (3); When the bed temperature measuring point is at the bottom of the side of the boiler furnace wall (1), a mounting sleeve (3) is arranged below the bed temperature measuring point, the thermocouple (2) penetrates into the interior of the boiler furnace wall (1) through the mounting sleeve (3), the inner protective sleeve (5) is arranged on the outside of one end of the thermocouple (2) and is welded to the mounting sleeve (3), and the outer protective sleeve (6) is arranged on the outside of the inner protective sleeve (5).

2. The anti-wear protection method for bed temperature measuring points of a circulating fluidized bed boiler according to claim 1 is characterized in that: The inner diameter of the wear-resistant sleeve (4) is 10 mm larger than the outer diameter of the thermocouple (2), and the wall thickness of the wear-resistant sleeve (4) is 3.5 mm.

3. The anti-wear protection method for bed temperature measuring points of a circulating fluidized bed boiler according to claim 2 is characterized in that: The wear-resistant sleeve (4) is made of 253MA stainless steel which is resistant to high temperature, wear and corrosion.

4. The anti-wear protection method for bed temperature measuring points of a circulating fluidized bed boiler according to claim 3 is characterized in that: The length of the inner protective sleeve (5) matches the length of the thermocouple (2) extending into the interior of the boiler furnace wall (1).

5. The anti-wear protection method for bed temperature measuring points of a circulating fluidized bed boiler according to claim 1 is characterized in that: The inner diameter of the inner protective sleeve (5) is 10 mm larger than the outer diameter of the thermocouple (2), and the wall thickness of the wear-resistant sleeve (4) is 3.5 mm.

6. The method for anti-wear protection of bed temperature measuring points of a circulating fluidized bed boiler according to claim 5, characterized in that: The inner protective sleeve (5) is made of 253MA stainless steel which is resistant to high temperature, wear and corrosion.

7. The anti-wear protection method for bed temperature measuring points of a circulating fluidized bed boiler according to claim 6 is characterized in that: The outer diameter of the outer protective sleeve (6) is 4 mm greater than the outer diameter of the inner protective sleeve (5), and the wall thickness of the outer protective sleeve (6) is 4 mm.

8. The method for anti-wear protection of bed temperature measuring points of a circulating fluidized bed boiler according to claim 6, characterized in that: The outer protective sleeve (6) is made of 253MA stainless steel which is resistant to high temperature, wear and corrosion.

9. The method for anti-wear protection of bed temperature measuring points of a circulating fluidized bed boiler according to claim 6, characterized in that: When the bed temperature measurement point is at the bottom of the boiler furnace wall (1), the length of the thermocouple (2) extending into the interior of the boiler furnace wall (1) is greater than 500 mm.

10. The method for anti-wear protection of bed temperature measuring points of a circulating fluidized bed boiler according to claim 1, characterized in that: Before the anti-wear protection structure is installed at the bed temperature measuring point of the boiler furnace wall (1), the corresponding position of the boiler furnace wall (1) is pretreated. The pretreatment includes cleaning, rust removal and coating of an anti-corrosion coating, so as to improve the bonding strength and service life of the anti-wear protection structure and the boiler furnace wall (1).

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