Temperature measuring device of combustion furnace

Abstract

The utility model discloses a temperature measuring device for a combustion furnace, and aims to solve the problem that a thermocouple of a high-temperature combustion furnace is short in service life. The combustion furnace temperature measuring device is installed in the furnace wall and fixed to the furnace wall in a matched mode, the temperature measuring thermocouple head is placed in a groove or a pit of the heat storage brick and connected with the compensation wire, a large spiral ring and a small spiral ring are machined on the compensation wire, the small spiral ring and the steel pipe section are fixed into a whole through insulating resin, and the large spiral ring and the ceramic pipe section are relatively fixed through heat preservation cotton. The outer sides of the steel pipe section and the ceramic pipe section are filled with heat preservation cotton or castable, and the steel pipe section and the ceramic pipe section are fixedly positioned with the furnace wall. And except for the thermocouple head, a heat insulation layer with the thickness of 5-10mm is arranged between other parts of the temperature measuring device and the heat storage layer. The device is installed in the furnace wall, the problems of oxidation and corrosion of furnace gas are avoided, the service life is prolonged, heat dissipation is reduced from multiple aspects, and long-time continuous temperature measurement is achieved.

Description

Technical Field

[0001] The utility model is applied to the field of combustion furnaces and relates to a temperature measurement system of a high-temperature combustion furnace, in particular to a temperature measurement device for indirectly measuring the furnace temperature. Background Art

[0002] Due to cost issues, large heating furnaces are mostly combustion furnaces, mainly gas-fired. Thermocouples are mostly used for temperature measurement in combustion furnaces. The temperature measuring couple head is set in a stainless steel protective tube and electrically connected to the temperature measuring instrument through a compensation wire. The temperature measuring end of the thermocouple is inserted into the furnace cavity of the combustion furnace. The temperature signal is converted into a thermoelectric potential signal by using the different microvoltages of the couple head at different temperatures, and then transmitted to the temperature measuring instrument, and the temperature value in the furnace is directly displayed on the temperature measuring instrument. However, for high-temperature combustion furnaces greater than 1000℃, not only is the temperature high, but the combustion exhaust gas contains oxidizing gases and corrosive gases, which can easily reduce the service life of the stainless steel protective tube. Especially for continuously operating high-temperature combustion furnaces, such as cracking furnaces, the temperature measuring thermocouples are rarely set in the high-temperature radiation section, but are mostly set in the relatively low-temperature convection section (800-900℃) to indirectly control the temperature of the radiation section. In order to improve the service life of the protection tube, CN116121599A provides an alloy material and a thermocouple protection sleeve for a thermocouple protection sleeve, which adopts a nickel-based alloy, Cr is about 1 / 4, and contains alloys such as W, Ti, and Co. The protection sleeve has excellent high temperature resistance, corrosion resistance, and erosion resistance. It is not easy to break in the environment of a high-temperature gas-cooled reactor and a coal-fired boiler, and the thermocouple can be used for more than two months. The protection sleeve is an expensive nickel-based alloy, which is not economical. CN211401461U discloses a thermocouple for sulfur recovery of coke oven gas, which solves the problem of temperature measurement of high-temperature corrosive gases. A box is set in the ventilation pipe, and the thermocouple is inserted into the box. An air inlet is opened on one side of the box, and an air outlet is opened on the other side. A filter plate is installed on the inner wall, and a filter screen is installed on the top inner wall. Activated carbon is provided on the outside of the filter plate and the filter screen, and the activated carbon is used to adsorb corrosive gases to reduce corrosion to the thermocouple. Multiple rotating rods and gears are designed in the box to adjust the temperature measurement position. This patent provides an idea, but it lacks many things. First, whether the mechanical rotating device can meet the high temperature requirements under high temperature conditions, and second, whether the activated carbon can adsorb corrosive gases under high temperature conditions. In short, this patent has almost no practical value. CN218673952U discloses a thermocouple temperature measuring device for a coalification furnace, which is also not of practical value. First, the compensation wire must be directly connected to the temperature measuring couple head, otherwise the temperature measurement will be inaccurate, and second, whether the mechanical device can work effectively under high temperature conditions. CN103245431B discloses a thermocouple for measuring flue gas, which solves the problem of impact corrosion of flue gas particles on the thermocouple protection tube, but does not solve the corrosion of the protection tube by corrosive gases.

[0003] For a continuously operating high-temperature combustion furnace, the furnace wall temperature can replace the gas temperature in the furnace cavity. Therefore, the present application utilizes the measurement of the furnace wall temperature to replace the measurement of the gas temperature in the furnace cavity. Utility Model Content

[0004] The technical problem solved by the utility model is to provide a combustion furnace temperature measuring device, which is combined with the furnace wall structure of the combustion furnace to accurately measure the temperature of the heat storage layer, so as to achieve the purpose of indirectly measuring the furnace chamber temperature of the combustion furnace. The temperature measuring dipole does not contact with high-temperature corrosive gas, does not need protection from a protective tube, can continuously measure temperature for a long time, and meets the temperature measurement requirements of continuously operating high-temperature combustion furnaces.

[0005] The technical solution adopted by the utility model is: the temperature measuring device of the combustion furnace is installed in the furnace wall and fixed with the furnace wall. The temperature measuring device includes a pair head, a compensation wire, a steel pipe section, and a ceramic pipe section. The pair head is placed in the groove or pit outside the heat storage brick, the pair head is connected to the compensation wire, and the compensation wire is electrically connected to the temperature measuring instrument. The compensation wire is installed in the steel pipe section and the ceramic pipe section, and two spiral rings similar to the shape of a spring are processed on the compensation wire, which are a large spiral ring and a small spiral ring. The small spiral ring is fixed to the steel pipe section as a whole through insulating resin; the large spiral ring is relatively fixed to the ceramic pipe section through insulation cotton, and the mobility is retained. Insulation cotton or casting material is filled on the outside of the steel pipe section and the ceramic pipe section, and fixed and positioned between the insulation layer of the furnace wall. During installation, the spacing between the steel pipe section and the ceramic pipe section should be retained to facilitate the subsequent adjustment to increase the elasticity of the large spiral ring. The insulating resin in the steel pipe section can be replaced by insulating materials such as rubber, plastic, mica, glass, or electric porcelain, and the small spiral ring and the steel pipe section can be fixed as a whole.

[0006] Preferably, the furnace wall includes a heat storage layer, an insulation layer, a thermal insulation layer and an outer wall from the inside to the outside, and the thermal insulation layer is composed of thermal insulation bricks and thermal insulation cotton; except for the head, a thermal insulation layer is provided between other components of the temperature measuring device and the heat storage layer to avoid heat dissipation due to the temperature measuring device. The thermal insulation layer is an aerogel thermal insulation material, the base layer of which is resistant to high temperatures and adopts nanopore thermal insulation. The product is in a paste form, and the water evaporates to form an insulation layer after the slurry is applied. The thickness of the thermal insulation layer is preferably 5-10 mm.

[0007] Preferably, the depth of the groove or pit is determined by the thermal conductivity of the heat storage layer, while taking into account the shrinkage of the compensation wire.

[0008] Preferably, the steel pipe section is connected to a flat plate, and the flat plate is fixed to the furnace wall by fasteners to fix the temperature measuring device.

[0009] The utility model has the following beneficial effects: the utility model is installed in the furnace wall, which eliminates the oxidation and corrosion problems of furnace gas and increases the service life of the temperature measuring device. There is no protective tube and the cost is low. The large screw ring is conducive to adjusting the position of the coupler head and ensuring the accuracy of temperature measurement. The paste-like insulation material is conducive to the installation of the coupler head and helps to fix the coupler head after drying. The utility model reduces heat dissipation from multiple aspects and can realize long-term continuous temperature measurement of the temperature measuring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic structural diagram of a temperature measuring device of Example 1;

[0011] Figure 2 is a schematic structural diagram of a temperature measuring device according to Embodiment 2;

[0012] In the figure: 1-heat storage layer, 2-insulating layer, 3-insulating bricks, 4-insulating cotton, 5-outer wall, 6-flat plate, 7-fasteners, 8-insulating resin, 9-compensating wire, 10-steel pipe section, 11-small screw ring, 12-ceramic pipe section, 13-large screw ring, 14-head, 15-casting material. DETAILED DESCRIPTION

[0013] The inside and outside mentioned below refers to the direction from the furnace cavity to the outside of the furnace, with the furnace cavity being the inside and the outside of the furnace being the outside. Example

[0014] The temperature measuring device of this embodiment is as shown in the attached Figure 1 As shown, it is installed in the furnace wall of the combustion furnace and fixed with the furnace wall, including a pair head 14, a compensation wire 9, a flat plate 6, a steel pipe section 10, an insulating resin 8, a ceramic pipe section 12, etc.

[0015] The furnace wall includes heat storage layer 1, insulation layer 2, thermal insulation layer and outer wall 5 from inside to outside. The heat storage layer 1 is built by heat storage bricks and directly contacts the high-temperature furnace gas. The heat storage bricks are required to be resistant to high temperatures and have high high-temperature strength, that is, high refractoriness and high softening point; good chemical stability, that is, no chemical reaction with furnace gas; good volume stability, that is, from room temperature to high temperature, there will be no large expansion or contraction due to recrystallization or sintering; it has air permeability, and the moisture in the insulation layer can evaporate when the furnace wall is baked; it has a certain thermal conductivity, and the temperature of the heat storage bricks can be used to replace the temperature of the furnace gas or the temperature of the heating components in the furnace. Corundum bricks, such as chrome corundum and aluminum corundum, are suitable for heat storage bricks. The insulation layer 2 uses aerogel insulation material, which is a new product developed by a high-tech enterprise in Handan. The base material is resistant to high temperatures and uses nanopore insulation. The product is paste-like. During construction, the paste insulation material is scraped onto the wall, and the moisture evaporates to form an insulation layer with a thickness of 5-10mm. The 3.8mm thick sample plate was placed on a 2kw electric furnace. After 24 hours, the infrared temperature gun measured only 87℃, and the insulation effect was excellent. Since the product cannot withstand the impact of high-temperature furnace gas, it is set between the heat storage layer and the insulation layer. Considering that there is air heat dissipation in the above test, the insulation layer in the furnace wall should be thickened to ensure the insulation effect. Another advantage of the paste aerogel insulation material is that it can be squeezed and deformed during construction to fill the brick joints, ensure the bite joints between the heat storage layer and the insulation layer, and thus ensure the integrity of the furnace wall. The insulation layer is composed of insulation bricks 3 and insulation cotton 4. The insulation bricks 3 are porous lightweight refractory bricks and are the main supporting components of the furnace wall. The insulation cotton 4 is a porous fiber material, and its main purpose is to prevent convection heat dissipation. The outer wall 5 is a steel plate, which is a structural member supporting burners, temperature measuring devices, pipelines and other components.

[0016] The head 14 is a key component for temperature measurement. It is suitable to use platinum-rhodium material, and the temperature measurement capacity can reach 1300℃. The head 14 is directly connected to the compensation wire 9, and the other end of the compensation wire 9 is electrically connected to the temperature measuring instrument. A groove or pit is processed on the heat storage brick outside the heat storage layer, and the head is placed in the groove or pit to ensure effective contact with the heat storage brick. The shape of the groove or pit should be consistent with the head to increase the contact surface of the head and ensure the accuracy of temperature measurement. On the compensation wire 9, two spiral rings similar to the shape of a spring are processed, namely the large spiral ring 13 and the small spiral ring 11. The pitch of the large spiral ring 13 is relatively long, and its main purpose is: 1) It is convenient to adjust the length size to adapt to furnace walls of different thicknesses; 2) It has a certain elasticity, so that the head can be compacted in the groove or pit of the heat storage brick to ensure the accuracy of temperature measurement; 3) Increase the length of the compensation wire and reduce external conduction heat dissipation. The large spiral ring 13 is located inside the ceramic pipe section 12, and the ceramic pipe section has the characteristics of insulation, high temperature resistance, and low thermal conductivity. When the large spiral ring 13 is installed in the ceramic pipe section 12, it is supported by thermal insulation cotton and relatively fixed, so that the large spiral ring 13 retains the ability to move left and right. The pitch of the small spiral ring 11 is relatively short, and it is located inside the steel pipe section 10. The steel pipe section 10 is welded and fixed to the flat plate 6, or is integrated. The flat plate 6 and the outer wall 5 are fixedly connected by fasteners 7. Insulating resin 8 is injected into the steel pipe section 10 to fix the small spiral ring 11, which is integrated with the steel pipe section 10 and the flat plate 6. At the same time, the compensation wire is insulated to ensure the accuracy of the temperature measurement data.

[0017] When installing this temperature measuring device, a through hole is processed on the insulation brick corresponding to the installation hole of the outer wall, and the diameter of the through hole is larger than the outer diameter of the ceramic pipe section and the steel pipe section. After the insulation brick is laid, the head and the ceramic pipe section are inserted into the through hole. After the end of the ceramic pipe section is flush with the insulation brick, check and adjust the length of the head protruding, and fix the temperature measuring device with fasteners. Before the ceramic pipe section is inserted into the through hole, it is wrapped with insulation cotton, and the gap between the ceramic pipe section and the through hole is filled with insulation cotton to avoid convective heat dissipation, and at the same time it is conducive to the friction fixation and positioning of the ceramic pipe section. While the insulation layer is scraped on the surface of the insulation brick, the heat storage layer is laid, and the head is placed in the groove or pit. The insulation layer paste is also filled in the groove or pit. Due to the elasticity of the large spiral ring, the head is pressed into the groove or pit, and it has good contact with the heat storage brick. The temperature measuring device is installed.

[0018] It should be noted that: 1) The insulating resin in the steel pipe section can be replaced by other insulating materials as long as it meets the purpose of insulation and fixing the small screw ring, such as rubber, plastic, mica, glass, electric porcelain, etc.; 2) The ceramic pipe section should be connected with multiple sections in a concave-convex positioning manner, which is more conducive to reducing the conductive heat transfer of the ceramic tube; 3) In the subsequent temperature measurement process, the heat transfer of the temperature measuring device is mainly the heat transfer of the temperature measuring coupler and the compensation wire. Even if the local compensation wire connected to the coupler loses its elasticity due to high temperature, the part with lower temperature at the rear end still retains its elasticity, and the part that loses elasticity is fixed by the insulation layer and thermal insulation cotton, which can still make the coupler fully contact with the heat storage brick to ensure the accuracy of temperature measurement; 4) If the thermal expansion and contraction of the compensation wire is considered, the groove or pit should have a certain depth to avoid the coupler head shrinking out of the groove or pit after the furnace is shut down. In order to achieve that the temperature display of the heat storage brick is consistent with the temperature of the heating components in the combustion furnace, the depth of the grooves and pits is mainly determined by the thermal conductivity, or thermal conductivity coefficient, of the heat storage brick, especially the high-temperature thermal conductivity coefficient; 5) A spacing should be left between the steel pipe section and the ceramic pipe section. In the subsequent production and use process, the large screw ring can be compressed by screwing the fasteners to increase the elasticity of the compensation wire again; 6) The scraping described in this application is similar to applying an insulation layer or cement layer on the inner surface of the wall. Example

[0019] This embodiment is an improvement on the embodiment 1, and its structure is as shown in the attached figure. Figure 2 As shown. In this embodiment, the heat insulation cotton outside the ceramic pipe section is replaced by the castable 15. The main function of the heat insulation layer is to build the main body of the furnace wall, and the second function is heat preservation. The function of preventing heat dissipation is basically undertaken by the heat insulation layer.

[0020] When constructing the furnace wall insulation bricks of this embodiment, it is not necessary to process the through holes for installing the ceramic pipe sections, and there is no problem of whether the through holes are concentric with the outer wall installation holes. The temperature measuring device is placed in the brick seams of the insulation bricks, and the refractory castable is poured, which is convenient and quick to construct.

[0021] The temperature measuring device of the utility model is installed in the furnace wall, and no expensive protective tube is used, so the cost is low. The temperature measuring device does not contact the furnace gas, which eliminates the oxidation and corrosion problems of the furnace gas and greatly increases the service life of the temperature measuring device. The large spiral ring structure is conducive to adjusting the position of the coupler head and ensuring full and effective contact between the coupler head and the heat storage brick, thereby ensuring the accuracy of temperature measurement. The paste-like insulation material is conducive to the construction of the furnace wall and the installation of the coupler head, and the dried insulation layer helps to fix the coupler head. The utility model reduces heat dissipation from multiple aspects, and can realize long-term continuous temperature measurement of the temperature measuring device.

Claims

1. A combustion furnace temperature measuring device, characterized in that: The device is installed in a furnace wall and fixed with the furnace wall, and comprises a head (14), a compensation wire (9), a steel pipe section (10), and a ceramic pipe section (12); the head (14) is placed in a groove or a pit on the outside of a heat storage brick of the furnace wall, the head (14) is connected to the compensation wire (9), and the compensation wire (9) is installed in the steel pipe section (10) and the ceramic pipe section (12); a large spiral ring (13) and a small spiral ring (11) are processed on the compensation wire (9); the small spiral ring (11) is fixed to the steel pipe section (10) as a whole through an insulating resin (8); and the large spiral ring (13) is relatively fixed to the ceramic pipe section (12) through thermal insulation cotton.

2. A combustion furnace temperature measuring device according to claim 1, characterized in that: The steel pipe section (10) and the ceramic pipe section (12) are filled with thermal insulation cotton or castable material on the outside and are fixedly positioned between the furnace wall.

3. A combustion furnace temperature measuring device according to claim 1, characterized in that: The insulating resin (8) is replaced by rubber, plastic, mica, glass, or electric porcelain.

4. A combustion furnace temperature measuring device according to claim 1, characterized in that: The furnace wall comprises a heat storage layer, a heat insulating layer, a thermal insulation layer and an outer wall from the inside to the outside. The thermal insulation layer is composed of thermal insulation bricks and thermal insulation cotton. A heat insulating layer is arranged between the temperature measuring device and the heat storage layer.

5. A combustion furnace temperature measuring device according to claim 4, characterized in that: The thickness of the thermal insulation layer is 5-10 mm.

6. A combustion furnace temperature measuring device according to claim 4, characterized in that: The steel pipe section (10) is connected to a flat plate, and the flat plate is fixed to the outer wall via fasteners.

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