Incinerator and incineration heat recovery system thereof
By using an air jacket and induced draft fan design, the problems of low-temperature corrosion and high cost in the incinerator were solved, achieving safe and economical heat recovery and temperature control, and reducing the use of internal insulation materials and gas consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HANGZHOU BAINENG TECH CO LTD
- Filing Date
- 2023-05-26
- Publication Date
- 2026-06-23
AI Technical Summary
Incinerators face a difficult balance between low-temperature corrosion and high-temperature costs. Increasing the thickness of the internal insulation material leads to higher costs and increases the risk of corrosion to the cylinder. Existing technologies are insufficient to effectively avoid low-temperature corrosion and reduce costs.
An air-jacket design is adopted, which uses natural or forced convection heat transfer between the air in the air-jacket and the shell to ensure that the shell temperature is higher than the flue gas dew point temperature. Combined with an induced draft fan and a cooling fan to regulate airflow, it prevents low-temperature corrosion and recovers heat through a heat recovery component to reduce gas consumption.
It effectively inhibits low-temperature corrosion, reduces the amount and cost of internal insulation materials, increases combustion temperature, reduces gas consumption, ensures safe use, and reduces shell load.
Smart Images
Figure CN116557868B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of incineration equipment technology, specifically to an incinerator and its incineration heat recovery system. Background Technology
[0002] The chemical industry generates large amounts of waste gas and waste liquid while producing end products. Increasingly stringent environmental standards require that these waste gases and liquids be treated to meet emission standards. Incineration is a crucial method for treating waste gas and waste liquids. As a key piece of equipment in the incineration process, the incinerator must be designed for safe and stable operation under harsh conditions to avoid affecting the normal operation of the main chemical processes. Incinerators often use adiabatic combustion to remove harmful substances from waste gas and waste liquids. The combustion temperature must reach a sufficient level to fully burn off harmful substances. Therefore, the internal insulation material of the incinerator must withstand the dual challenges of high temperatures and the atmosphere of waste gas and waste liquid, thus placing higher demands on the internal insulation material. Furthermore, the steel cylinder of the incinerator has low thermal resistance, and the inner surface temperature is close to the outer surface temperature. The inner surface may come into contact with corrosive waste liquids and gases, which can accelerate corrosion within a certain temperature range, threatening the safety of the cylinder.
[0003] Low-temperature corrosion is sulfuric acid corrosion that occurs on the heating surfaces at the tail end of a boiler. Because the flue gas and tube wall temperatures in the tail heating surface section are relatively low, it is called low-temperature corrosion. Low-temperature corrosion can also occur in air preheaters and economizer tubes. The main factors causing low-temperature corrosion include the following: (1) Sulfur content in flue gas: The higher the sulfur content, the more SO3 may be converted, and the higher the acid dew point; (2) Excess air coefficient α: The higher the excess air coefficient, the more O2 is produced, and the more SO3 is produced by the oxidation reaction; (3) Surface metal temperature of the heating surface: Within the common tail heating surface wall temperature range of boilers, the wall temperature and corrosion rate are not linearly related. However, the lower the wall temperature, the more severe the corrosion. When the flue gas temperature is below a certain critical temperature, the corrosion rate will increase rapidly.
[0004] Incinerators are also susceptible to low-temperature corrosion. Given the complexity and diversity of chemical processes and products, the factors influencing low-temperature corrosion are even more complex. Therefore, the internal wall temperature must be carefully considered during incinerator design. The combustion temperature of the incinerator is much higher than the temperature at which low-temperature corrosion may occur, but the internal insulation material keeps the incinerator cylinder temperature close to ambient temperature. High-temperature flue gas, passing through the gaps in the internal insulation material and installation seams, comes into contact with the inner cylinder and condenses upon cooling, potentially causing low-temperature corrosion of the cylinder.
[0005] Furthermore, the external wall temperature is usually a concern for project owners; the temperature must not exceed their requirements to ensure maintenance and repair needs. If relying solely on internal insulation to control the external wall temperature, the insulation thickness may be very thick, leading to a rapid increase in cost for high-quality internal insulation materials. The closer the external wall temperature is to ambient temperature, the faster the cost increases. The cylinder body must simultaneously bear the weight and load of the internal insulation material. Increased internal insulation also poses a greater challenge to the cylinder's strength, sometimes necessitating an increase in thickness. The cylinder body has relatively low thermal resistance compared to other components, and the internal temperature is close to the external wall temperature. A decrease in external wall temperature increases the likelihood of corrosion when the internal gas cools. Summary of the Invention
[0006] 1. The technical problem that the invention aims to solve
[0007] To address the aforementioned technical problems, this invention provides an incinerator and its combustion heat recovery system. Heat transfer between the air in the air jacket and the shell is achieved through natural or forced convection, ensuring that the incinerator shell temperature is higher than the dew point temperature of the combustion flue gas that may penetrate the inner insulation layer and come into contact with the shell, thus preventing low-temperature corrosion. The heat from combustion, after heat exchange in the air jacket, is sent to the air preheater by an induced draft fan. After preheating in the preheater, the air is then transported back to the incinerator burner via a regenerative pipeline through an air box for combustion, which helps to increase the combustion temperature and reduce fuel consumption.
[0008] 2. Technical Solution
[0009] To solve the above problems, the technical solution provided by the present invention is as follows: an incinerator, comprising an inner insulation component, a shell, and an air jacket component arranged sequentially from the inside to the outside. The air jacket component includes an air jacket, an air insulation layer, and a protective layer arranged sequentially from the inside to the outside. The air jacket is connected to a cold air fan and an exhaust fan assembly. The cold air fan sends cold air into the air jacket, and the exhaust fan assembly draws hot air out of the air jacket, so that the temperature of the air in the air jacket is between the temperature of the outer wall of the shell and the temperature of the protective layer.
[0010] Optionally, the internal insulation component includes a low-silica high-alumina refractory brick layer, a heat-insulating lightweight insulation brick layer, and an aluminosilicate ceramic fiber blanket layer arranged sequentially from the inside to the outside, with the aluminosilicate ceramic fiber blanket layer disposed on the inner side wall of the shell.
[0011] Optionally, the low-silicon, high-alumina refractory brick layer may be made of chrome corundum, corundum, or high-chromium brick.
[0012] Optionally, the induced draft assembly includes a hot air duct and an induced draft fan. The air inlet of the hot air duct is connected to an air jacket, the air outlet of the hot air duct is connected to the air inlet of the induced draft fan, and the air outlet of the induced draft fan is used to connect to the regenerative assembly.
[0013] Optionally, the inner wall of the housing is coated with an acid-resistant coating, the thickness of which is 0.5 to 3 mm.
[0014] The present invention also discloses an incinerator incineration heat recovery system, including a regenerating component and the incinerator described above. The regenerating component includes an air preheater, a wind box and a regenerating pipe connected in sequence. The air outlet of the induced draft fan is connected to the air inlet of the air preheater, and the air outlet of the regenerating pipe is connected to the shell of the incinerator.
[0015] Optionally, the air intake assembly further includes a cold air duct, which is connected to a hot air duct, and the cold air duct is equipped with a regulating valve.
[0016] Optionally, it also includes a connecting flue and a waste heat boiler, wherein one end of the connecting flue is connected to the shell and the other end of the connecting flue is connected to the waste heat boiler, and the bottom of the shell is provided with a slag outlet.
[0017] Optionally, the bottom of the shell is higher than the bottom of the connecting flue, the bottom of the connecting flue is higher than the bottom of the waste heat boiler, and the bottom of the shell, the bottom of the connecting flue, and the bottom of the waste heat boiler are inclined downwards in the direction of the shell.
[0018] Optionally, the inner wall of the connecting flue is provided with a flue insulation layer, which consists of a low-silicon high-alumina refractory brick layer, a heat-insulating lightweight insulation brick layer, and an aluminum silicate ceramic fiber blanket layer arranged sequentially from the inside to the outside. The aluminum silicate ceramic fiber blanket layer is arranged on the inner wall of the connecting flue.
[0019] 3. Beneficial effects
[0020] Compared with the prior art, the technical solution provided by this invention has the following advantages:
[0021] (1) The incinerator proposed in this application embodiment utilizes natural or forced convection heat transfer between the air in the air jacket and the shell. The heated air is significantly warmer than the ambient temperature outside the air jacket, increasing the temperature difference between the inner wall of the incinerator shell and the ambient temperature. This ensures the incinerator shell temperature is higher than the dew point temperature of the combustion flue gas that may penetrate the inner insulation layer and contact the shell, preventing low-temperature corrosion. Simultaneously, to prevent burns to maintenance and inspection personnel, airflow is accelerated using a cooling fan and induced draft assembly, causing the temperature within the air jacket to decrease gradually, ensuring the outer wall temperature of the protective layer does not exceed the required engineering temperature range, thus ensuring safe operation. The complementary advantages of the inner insulation and the air jacket effectively inhibit corrosion, thermal shock, and erosion from acidic substances and salts. While ensuring the service life of the inner insulation, it maintains the outer wall temperature of the shell at 150-180℃, thereby eliminating the problem of low-temperature corrosion within the furnace shell. This solution reduces the amount of internal insulation material used, effectively lowering costs. The weight of the internal insulation material and the external air jacket assembly, as well as other loads, are all supported by the furnace shell of the incinerator. Therefore, effectively reducing the weight of the internal insulation can reduce the load on the shell and reduce the thickness of the shell.
[0022] (2) In the incinerator heat recovery system proposed in this application embodiment, the concentrate and natural gas enter the furnace from the inlet at the top of the shell for combustion. The heat from the combustion is exchanged through the air jacket and then sent to the air preheater by the induced draft fan. After being preheated by the air preheater, it is transported back to the burner of the incinerator through the air box and the heat recovery pipe for combustion. This is beneficial to increase the combustion temperature, reduce the emission of harmful substances, and at the same time, the required combustion gas is reduced accordingly, thus reducing the external heat input. Attached Figure Description
[0023] Figure 1 This is a schematic diagram showing the connection between the incinerator and the waste heat boiler of the present invention.
[0024] Figure 2 This is a schematic diagram of the structure of the incinerator insulation component and air jacket component of the present invention.
[0025] Figure 3 This is a schematic diagram of the temperature gradient inside the incinerator of the present invention, from the furnace chamber through the internal insulation component, the shell, the air jacket component, and finally to the surrounding environment.
[0026] Figure 4 This is a schematic diagram of the temperature gradient of an incinerator without an air jacket assembly.
[0027] Figure 5 This is a schematic diagram of the incinerator heat recovery system of the present invention.
[0028] The labels in the attached figures are as follows: 1. Shell; 2. Internal insulation component; 201. Low-silica high-alumina refractory brick layer; 202. Thermal insulation lightweight insulation brick layer; 203. Alumina silicate ceramic fiber blanket layer; 3. Air jacket component; 301. Air jacket; 302. Air insulation layer; 303. Protective layer; 4. Exhaust fan component; 401. Hot air duct; 402. Exhaust fan; 403. Cold air duct; 404. Regulating valve; 5. Air preheater; 6. Expansion joint; 7. Air box; 8. Regenerative pipe; 9. Connecting flue; 10. Waste heat boiler; 11. Furnace; 12. Primary air regulating damper; 13. Secondary air regulating damper; 14. Regulating damper to secondary natural gas burner; 15. Primary air annular duct; 16. Secondary air annular duct; 17. Primary natural gas burner; 18. Secondary natural gas burner; 19. Primary air nozzle; 20. Secondary air nozzle. Detailed Implementation
[0029] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments.
[0030] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. The terms "first," "second," etc., used in this invention are for the convenience of describing the technical solutions of the invention and have no specific limiting effect; they are all general terms and do not constitute a limitation on the technical solutions of the invention. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, not to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Multiple technical solutions in the same embodiment, as well as multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not contradict or conflict, all of which are within the scope of protection claimed by this invention.
[0031] This invention discloses an incinerator, comprising an inner insulation component 2, a shell 1, and an air jacket component 3 arranged sequentially from the inside to the outside. The air jacket component 3 includes an air jacket 301, an air insulation layer 302, and a protective layer 303 arranged sequentially from the inside to the outside. The air jacket 301 is connected to a cold air fan and an exhaust fan 4. The cold air fan sends cold air into the air jacket 301, and the exhaust fan 4 draws hot air out of the air jacket 301, so that the temperature of the air in the air jacket 301 is between the temperature of the outer wall of the shell 1 and the temperature of the protective layer 303. Because the air within the air jacket 301 and the shell 1 undergo natural or forced convection heat transfer, the heated air is significantly warmer than the ambient temperature outside the air jacket. This increases the temperature difference between the inner wall of the incinerator shell and the ambient temperature, ensuring that the incinerator shell temperature remains above the dew point temperature of the flue gas that may penetrate the inner insulation layer and come into contact with the shell, thus preventing low-temperature corrosion. Simultaneously, to prevent burns to maintenance and inspection personnel, the airflow is accelerated by a cooling fan and induced draft assembly 4, causing the temperature within the air jacket 301 to decrease gradually, ensuring that the outer wall temperature of the protective layer 303 does not exceed the required engineering temperature range, guaranteeing safe operation. The complementary advantages of the inner insulation layer and the air jacket 301 effectively inhibit corrosion, thermal shock, and erosion from acidic substances and salts. While ensuring the service life of the inner insulation, it maintains the outer wall temperature of the shell 1 at 150-180℃, thereby eliminating the problem of low-temperature corrosion of the steel shell 1 inside the furnace. This solution reduces the amount of insulation material used inside the shell 1, effectively lowering costs. The weight of the internal insulation material and the external air jacket assembly 3 of the shell 1, as well as other loads, are all supported by the furnace shell 1 of the incinerator. Therefore, effectively reducing the weight of the internal insulation can reduce the load on the shell 1 and reduce the thickness of the shell 1.
[0032] The internal insulation component 2 includes, from the inside out, a low-silica high-alumina refractory brick layer 201, a heat-insulating lightweight brick layer 202, and an aluminosilicate ceramic fiber blanket layer 203, with thicknesses of 200mm for the low-silica high-alumina refractory brick layer, 100mm for the heat-insulating lightweight brick layer, and 100mm for the aluminosilicate ceramic fiber blanket layer, respectively. The aluminosilicate ceramic fiber blanket layer 203 is disposed on the inner sidewall of the shell 1.
[0033] from Figure 3 The diagram illustrates the temperature gradient from the combustion temperature inside the furnace to the ambient temperature outside. The aluminosilicate ceramic fiber blanket layer 203, closest to the shell 1, has the highest thermal resistance and experiences the fastest temperature drop. The shell 1 has the lowest thermal resistance, and the temperature difference between its inner surface and outer wall is minimal. The air jacket 301 has a relatively high thermal resistance to heat exchange with the ambient air, resulting in a significant temperature difference between the flowing air in the air jacket 301 and the outer wall of the shell 1. This temperature difference is what keeps the inner wall of the shell 1 stably above the flue gas temperature range where low-temperature corrosion occurs.
[0034] In contrast. Figure 4This is a schematic diagram of the temperature of the shell 1 without the air interlayer 301. In order to achieve the same outer wall temperature, the heat-insulating lightweight brick layer 202 and the aluminum silicate ceramic fiber blanket layer 203 are significantly thicker. The inner wall temperature of the incinerator shell 1 is close to the ambient air temperature, which poses a risk of low-temperature corrosion under unfavorable flue gas conditions.
[0035] Depending on the properties and temperature of the combustion waste liquid and exhaust gas, the low-silicon, high-alumina refractory brick layer on the fire-facing side of the internal insulation component 2 can be made of chromium corundum, corundum, or high-chromium bricks. This embodiment uses a chromium corundum brick layer with a chromium content greater than 8% and a thickness of 200mm. Chromium corundum effectively inhibits corrosion from acidic substances and salts, as well as thermal shock and erosion. In areas with irregular structures or where heavy loads are applied, chromium corundum castable and lightweight insulating castable can be used. The induced draft component 4 includes a hot air duct 401 and an induced draft fan 402. The inlet of the hot air duct 401 is connected to the air jacket 301, and the outlet of the hot air duct 401 is connected to the inlet of the induced draft fan 402. The outlet of the induced draft fan 402 is used to connect to the regenerative component.
[0036] The inner wall of the housing 1 is coated with an acid-resistant coating, the thickness of which is 0.5 to 3 mm.
[0037] This invention also discloses an incinerator heat recovery system, comprising the incinerator and a regeneration assembly as described above. The regeneration assembly includes an air preheater 5, a wind box 7, and a regeneration pipe 8 connected in sequence. The outlet of the induced draft fan 402 is connected to the inlet of the air preheater 5, and the outlet of the regeneration pipe 8 is connected to the shell 1 of the incinerator. Concentrated liquid and natural gas enter the furnace 11 from the inlet at the top of the shell 1 for combustion. The heat from combustion is exchanged through the air jacket 301 and then sent by the induced draft fan 402 to the air preheater 5. After preheating by the air preheater 5, the heat is transported back to the burner of the incinerator via the wind box 7 and the regeneration pipe 8 for combustion. This helps to increase the combustion temperature and reduce the emission of harmful substances. Simultaneously, the required combustion gas is reduced accordingly, decreasing the external heat input.
[0038] The air intake assembly 4 also includes a cold air duct 403, which is connected to a hot air duct 401. A regulating valve 404 is provided on the cold air duct 403. The cold air duct 403 and the hot air duct 401 form a mixed airflow. This mixed airflow enters the air preheater 5 through the air intake fan 402 for further heating. The cold air in the cold air duct 403 neutralizes the hot air in the hot air duct 401, preventing the hot air temperature from becoming too high and damaging the internal structure of the air intake fan 402.
[0039] It also includes a connecting flue 9 and a waste heat boiler 10. One end of the connecting flue 9 is connected to the shell 1, and the other end is connected to the waste heat boiler 10. The shell 1 has a slag outlet at its bottom. The ash produced by the combustion of waste liquid mainly consists of sodium carbonate, sodium bromide, and a small amount of metal oxides. After being discharged from the slag outlet of the incinerator, it is bagged and transported off-site after being cooled and crushed by equipment. A secondary natural gas burner 17 is installed at the bottom of the incinerator shell 1. The insulation scheme of this incinerator can maintain a high temperature in the incinerator, making liquid slag discharge possible. The waste heat boiler 10 recovers the waste heat of the high-temperature flue gas to generate steam with a certain pressure, which can either be supplied as steam or used to generate electricity through a steam turbine.
[0040] The bottom of the shell 1 is higher than the bottom of the connecting flue 9, and the bottom of the connecting flue 9 is higher than the bottom of the waste heat boiler 10. The bottoms of the shell 1, the connecting flue 9, and the waste heat boiler 10 are all inclined downwards towards the direction of the shell 1. The inclination angle of the bottoms of the shell 1, the connecting flue 9, and the waste heat boiler 10 is 3-6° to facilitate the flow and discharge of molten slag.
[0041] The inner wall of the connecting flue 9 is provided with a heat insulation layer for the connecting flue 9, the heat insulation layer having an alumina content greater than 80% and a thickness of 100-180mm.
[0042] The inner wall of the connecting flue is provided with a flue insulation layer. From the inside out, the flue insulation layer consists of a low-silica, high-alumina refractory brick layer, a heat-insulating lightweight brick layer, and an aluminosilicate ceramic fiber blanket layer. The aluminosilicate ceramic fiber blanket layer is located on the inner wall of the connecting flue. An air jacket is provided outside the connecting flue 9. The air in the air jacket is heated and then sent together with the air in the incinerator's air jacket by the induced draft assembly to the regenerator assembly to recover heat.
[0043] Example 1
[0044] The feed to the incinerator is concentrated wastewater evaporation residue. The incineration system, which is attached to the alkali recovery furnace, is equipped with one incinerator. The design feed flow rate of a single unit is 15t / h, the normal feed solid concentration is 50% to 70%, and the operating flexibility is 50% to 110%.
[0045] To maintain sufficient temperature in the incinerator, natural gas is used as auxiliary fuel, with a calorific value between 6600 kcal / Nm³. 3 ~9600kcal / Nm 3 between.
[0046] The concentrate contains high levels of Na+ and Br- ions, and the combustion flue gas contains a large amount of mixed salts of NaBr and Na2CO3. The refractory and heat-insulating materials used are furnace lining materials that are resistant to molten salt corrosion and high temperature.
[0047] The refractory insulation structure of the incinerator is designed to be compatible with the connection of the waste heat boiler 10, and is also compatible with the arrangement of the concentrated liquid burner, natural gas burner, manhole, observation hole and measuring point.
[0048] The incinerator shell 1 encloses the furnace chamber 11. Concentrated liquid and natural gas enter the furnace chamber 11 from the upper part of the shell 1 for combustion. The resulting flue gas is discharged from the lower rear wall and enters the waste heat boiler 10 through the connecting flue 9 to recover heat. A concentrated liquid burner and a natural gas burner are installed at the upper end, and a secondary air inlet is designed at the upper part of the incinerator. Considering both the ash discharge from the waste heat boiler 10 and the upstream incinerator furnace chamber 11, a secondary natural gas burner 17 is installed at the lower part to increase the temperature of the flue gas and ash, creating conditions for liquid ash discharge from the lower part of the incinerator furnace chamber 11. The ash produced from the combustion of the waste liquid mainly consists of sodium carbonate, sodium bromide, and a small amount of metal oxides. After being discharged from the lower part of the incinerator furnace chamber 11, it is cooled and crushed, bagged, and transported off-site.
[0049] Two slag discharge ports are arranged along the width direction at the lower part of the front wall of the incinerator 11 to discharge the molten slag from the incinerator and the high-temperature molten slag from the waste heat boiler 10. The lower parts of the incinerator 11, the waste heat boiler 10 and the connecting flue 9 are inclined at 5° to facilitate the flow and discharge of molten slag.
[0050] See Figure 1 Due to the different directions and magnitudes of thermal expansion, an expansion joint 6 is installed at the connection point between the connecting flue 9 and the waste heat boiler 10. The incinerator and the connecting flue 9 adopt an internal insulation and air jacket 301 scheme, while the waste heat boiler 10 adopts an external insulation structure.
[0051] See Figure 2 In this embodiment, the incinerator wall structure for preventing low-temperature corrosion includes an internal insulation layer and an air jacket 301. The air jacket 301 is located outside the incinerator shell 1, and the chromium corundum brick layer is located on the fire-facing side of the internal insulation component 2, directly contacting the incinerator furnace chamber 11. Chromium corundum bricks have excellent thermal shock stability and high-temperature creep resistance. Cr2O3 is the main corrosion-resistant material used in chromium corundum bricks; the higher the Cr2O3 content, the better the corrosion resistance. However, high-chromium chromium corundum bricks are expensive, and controlling the amount used is an objective requirement for cost reduction.
[0052] The total thickness of the internal insulation component 2 of the incinerator shell 1 is 400mm: the fire-facing side uses chrome corundum bricks with a chromium content greater than 8% and a thickness of 200mm; the refractory insulation layer uses mullite lightweight castable with a thickness of 100mm; the heat insulation layer uses ceramic fiber board or fiber blanket with a thickness of 100mm.
[0053] After welding the insulation material fasteners onto the shell 1, apply a layer of acid-resistant coating about 1 mm thick to the inner surface of the shell 1 to further reduce the risk of low-temperature corrosion of the shell 1.
[0054] The induced draft fan 402 draws hot air downwards from the air jacket 301, accelerating airflow. More heat dissipated from the shell 1 is carried away through air heat transfer, maintaining a lower temperature for the insulated furnace 11 cylinder and the outer wall of the air jacket 301, thus meeting customer requirements. The pressure head of the induced draft fan 402 must overcome the frictional and local resistance of the system's flue gas duct, as well as meet the resistance of the air jacket 301 and the requirements for self-ventilation.
[0055] Figure 5 The air in the air jacket 301 is supplied via forced convection. An induced draft fan 402 is installed at the lower outlet of the air jacket 301. Cold air is introduced from the upper part of the jacket by a cold air fan, and after convective heat exchange with the shell 1, it is extracted from the lower part of the air jacket 301 and sent as part of the combustion air into the insulated furnace 11 for combustion. This reduces the heat required to heat the air, and the induced draft fan 402 in the incinerator furnace 11 can also serve as the air fan for the air jacket 301, eliminating the need for an additional fan. The parameters of the blower remain essentially unchanged, thus not increasing costs. The gap thickness of the air jacket 301 is 100mm. Using forced convection, the wall temperature of the outer steel plate layer of the air jacket 301 does not exceed 50℃, meeting the high standards required by the owner and users. The process is as follows:
[0056] After the air in the incinerator and the air jacket 301 connecting the flue 9 absorbs heat, it enters the induced draft fan 402 through the hot air outlet of the centrally located air jacket 301, flows through the hot air duct 401 and into the cold air duct 403. A regulating valve 404 is installed on the cold air duct, and the temperature of the mixed air can be controlled by adjusting the air volume of the hot air duct 401 and the cold air duct 403 during operation. The mixed air through the induced draft fan 402 goes through the induced draft fan 402 to the inlet air duct of the air preheater 5, enters the air preheater 5, absorbs heat, and enters the air distribution box 7 through the outlet of the air preheater 5, and then enters the regenerator duct 8. The hot air volume enters the primary air annular duct 15 at the top of the furnace through the primary air regulating damper 12, the hot air volume enters the secondary air annular duct 16 through the secondary air regulating damper 13, and the hot air volume enters the secondary natural gas burner 18 through the regulating damper 14. The primary air from the annular primary air duct 15 at the top of the furnace passes sequentially through the primary natural gas burner 17 and several primary air nozzles 19 before entering the incinerator to mix and burn with the waste gas and waste liquid. Secondary air from the annular secondary air duct 16 is injected into the incinerator through several secondary air nozzles 20 to supplement the required oxygen. The hot air entering the secondary natural gas burner 18 burns in the lower part of the incinerator to maintain the temperature required for liquid ash discharge.
[0057] Example 2
[0058] In this embodiment, the air in the air jacket 301 is supplied by natural convection, eliminating the need for a cooler and an exhaust fan 402. The goal is to maximize the intake of cold air. No protective layer 303 is provided outside the air jacket 301. Cold air enters from the lower part of the air jacket 301 and through openings in its outer layer, while hot air exits from the top. The air gap is 100mm, and the upward flow velocity of natural convection is approximately 4m / s. The heat transfer coefficient between the steel shell 1 and the airflow in the air jacket 301 is relatively low, requiring a larger temperature difference for the same heat dissipation. This results in a higher wall temperature for the cylinder, and for the same temperature of the steel shell 1, its internal insulation thickness is less than that of the forced convection method. The naturally convected air is discharged upwards into the atmosphere, and its heat cannot be recovered.
[0059] The protective layer 303 is made of thin stainless steel plate or corrugated plate and is installed on the outermost layer of the furnace wall structure. It forms a relatively closed space, and by setting up canopies and labyrinth passages, it avoids direct contact between the first layer of the incinerator steel shell and rainwater, thus weakening external corrosion.
[0060] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.
Claims
1. A heat recovery system for incinerator combustion, characterized in that, The system includes a regenerating component and an incinerator. The incinerator includes an inner insulation component, a shell, and an air jacket component arranged sequentially from the inside out. The air jacket component includes an air jacket, an air insulation layer, and a protective layer arranged sequentially from the inside out. The air jacket is connected to a cold air fan and an exhaust fan assembly. The exhaust fan assembly includes a hot air duct and an exhaust fan. The cold air fan sends cold air into the air jacket, and the exhaust fan assembly draws hot air out of the air jacket, so that the temperature of the air in the air jacket is between the temperature of the outer wall of the shell and the temperature of the protective layer. The regenerative assembly includes an air preheater, a wind box, and a regenerative pipe connected in sequence. The outlet of the induced draft fan is connected to the inlet of the air preheater, and the outlet of the regenerative pipe is connected to the shell of the incinerator. The internal insulation component includes a low-silicon high-alumina refractory brick layer, a heat-insulating lightweight insulation brick layer, and an aluminum silicate ceramic fiber blanket layer arranged sequentially from the inside to the outside. The aluminum silicate ceramic fiber blanket layer is disposed on the inner side wall of the shell. The bottom of the shell is higher than the bottom of the connecting flue, and the bottom of the connecting flue is higher than the bottom of the waste heat boiler. The bottom of the shell, the bottom of the connecting flue, and the bottom of the waste heat boiler are all inclined downwards in the direction of the shell.
2. The incinerator heat recovery system according to claim 1, characterized in that, The low-silicon, high-alumina refractory brick layer is made of chrome corundum, corundum, or high-chromium brick.
3. The incinerator incineration heat recovery system according to claim 1, characterized in that, The inlet of the hot air duct is connected to the air jacket, the outlet of the hot air duct is connected to the inlet of the induced draft fan, and the outlet of the induced draft fan is used to connect to the regenerative assembly.
4. The incinerator incineration heat recovery system according to claim 1, characterized in that, The inner wall of the shell is coated with an acid-resistant coating, the thickness of which is 0.5~3mm.
5. The incinerator incineration heat recovery system according to claim 1, characterized in that, The air intake assembly also includes a cold air duct, which is connected to a hot air duct, and a regulating valve is provided on the cold air duct.
6. The incinerator incineration heat recovery system according to claim 1, characterized in that, It also includes a connecting flue and a waste heat boiler. One end of the connecting flue is connected to the shell, and the other end of the connecting flue is connected to the waste heat boiler. The bottom of the shell is provided with a slag outlet.
7. The incinerator incineration heat recovery system according to claim 6, characterized in that, The inner wall of the connecting flue is provided with a flue insulation layer. The flue insulation layer is provided with a low-silicon high-alumina refractory brick layer, a heat-insulating lightweight insulation brick layer and an aluminum silicate ceramic fiber blanket layer from the inside to the outside. The aluminum silicate ceramic fiber blanket layer is provided on the inner wall of the connecting flue.