Internal combustion type carbonization system based on whole-course spiral propulsion of materials

Abstract

The invention discloses an internal combustion type carbonization system based on material whole-course spiral propulsion, which comprises a carbonization furnace, a feeding auger, an ignition device, a first air blower and a second air blower, the carbonization furnace linearly extends along the left-right direction, and the right end of the carbonization furnace is provided with a carbon discharge port; a drying preheating area, a main carbonization spontaneous combustion area and a burnout carbon discharge area are sequentially formed in the hearth in the advancing direction of materials; through the partition design in the hearth and the whole-course penetrating layout of the feeding auger feeding pipe, materials are turned over, fed and carbonized in the pipe at the same time, and the problems of uneven carbonization and product quality fluctuation caused by static material accumulation or simple pushing of traditional external combustion type equipment are thoroughly solved; meanwhile, due to the internal combustion type design, pyrolysis gas can be spontaneously combusted in the furnace, heat directly acts on a feeding pipe and materials, heat loss caused by external combustion type double wall surface conduction is avoided, the heat utilization rate can be greatly improved, system self-circulation can be achieved under the condition that external continuous energy supply is not needed, and the operation cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomass raw material carbonization, and particularly relates to an internal combustion type carbonization system based on full-process spiral material pushing. BACKGROUND

[0002] Biomass carbonization technology is widely used in the field of resource utilization of agricultural and forestry waste. The existing carbonization furnace mostly adopts an external combustion heating structure, for example, a jacket or a heating cavity is arranged outside the hearth, and the hearth is heated by passing hot media such as high-temperature flue gas and steam into the jacket / heating cavity, so as to realize carbonization of the material in the furnace.

[0003] In the external combustion design, heat transfer needs to pass through the double conduction of the jacket wall and the hearth wall, and the heat loss is large, and the heat utilization rate is usually less than 50%, and the energy consumption is high. In addition, the temperature distribution in the furnace is uneven, and the material is mostly static accumulation or simple pushing, and it is difficult to fully contact the heat, and problems such as incomplete carbonization and product quality fluctuation are prone to occur.

[0004] At the same time, the feeding and carbonization processes of the existing carbonization equipment are independent of each other, and the material lacks effective overturning and stirring during conveying, and the carbonization reaction consistency is poor. The combustible pyrolysis gas generated by carbonization is mostly directly discharged or inefficiently burned, which not only wastes energy but also pollutes the environment.

[0005] In addition, the traditional equipment lacks targeted partitioned air supply and cooling design, the pyrolysis gas is not fully burned, the discharged charcoal is prone to secondary combustion due to untimely cooling, and the system needs to rely on external continuous energy supply, which further increases the operation cost and operation complexity. SUMMARY

[0006] The present application aims to overcome the deficiencies in the prior art, and provides an internal combustion type carbonization system based on full-process spiral material pushing.

[0007] The application provides an internal combustion carbonization system based on material whole-process spiral propulsion, comprising: a carbonization furnace, a hearth of the carbonization furnace extending linearly along a left-right direction, a right end of the hearth being provided with a charcoal discharging port, the hearth inside being sequentially formed with a drying preheating zone, a main carbonization self-ignition zone and a burnout charcoal discharging zone along a material advancing direction; a feeding auger, a feeding pipe of the feeding auger being inserted into the hearth and extending from the drying preheating zone to the burnout charcoal discharging zone, so that an outlet of the feeding pipe is close to the charcoal discharging port, the feeding auger being used for conveying biomass raw materials, the feeding pipe being provided with spiral blades, in working, the spiral blades are agitated, and the material can be turned, fed and carbonized in the feeding pipe; an ignition device, used for igniting combustible pyrolysis gas generated in the carbonization furnace due to carbonization; a first air blower, an air outlet of the first air blower being branched into a first ventilation pipeline and a second ventilation pipeline, the first ventilation pipeline being connected to the main carbonization self-ignition zone and used for providing main combustion air, the second ventilation pipeline being connected to the right end of the hearth and opposite to the outlet of the feeding pipe, used for forcibly cooling discharged charcoal; a second air blower, connected to the burnout charcoal discharging zone through a third ventilation pipeline, used for supplying secondary air to ensure sufficient burnout of combustible gas; with the carbonization proceeding, generated charcoal can be discharged through the charcoal discharging port; generated combustible pyrolysis gas can be self-ignited in the hearth, and finally, system self-circulation is realized.

[0008] Further, the feeding pipe and the spiral blades of the feeding auger are both made of high-temperature-resistant alloy, and the thermal conductivity thereof is not less than 10 W / (m·K); and / or, the advancing surface of the spiral blades and / or the inner wall of the feeding pipe are covered with a hard alloy wear-resistant layer formed by surfacing; and / or, the surface of the feeding pipe and / or the spiral blades is subjected to high-temperature aluminizing treatment; and / or, the feeding auger is provided with a cooling structure at a position outside the hearth, used for blocking high temperature in the hearth from being transmitted to driving components thereof; and / or, the edge of the spiral blades is provided with an elastic material scraping strip, used for removing materials adhered to the inner wall of the feeding pipe; and / or, the feeding pipe is fixedly arranged in the hearth through a high-temperature-resistant support structure, and the support structure is configured to allow thermal expansion of the feeding pipe.

[0009] Further, the first ventilation pipe, the second ventilation pipe and the third ventilation pipe are each provided with an adjusting valve for adjusting the air supply amount of the corresponding pipe to achieve accurate matching of the air amount for carbonization reaction and pyrolysis gas combustion; the carbonization system further comprises: a first temperature sensor for monitoring the temperature of the main carbonization self-ignition zone; a second temperature sensor for monitoring the temperature of the charcoal discharging port; a flue gas analyzer for monitoring the composition of the flue gas discharged by the carbonization furnace; a control unit electrically connected with the first temperature sensor, the second temperature sensor and the flue gas analyzer and signal connected with the actuator of the adjusting valve, the control unit being configured to execute the following control logic: adjusting the air supply amount of the first ventilation pipe according to the monitoring data of the first temperature sensor to stabilize the temperature of the main carbonization self-ignition zone within a preset range; adjusting the air supply amount of the second ventilation pipe according to the monitoring data of the second temperature sensor to control the charcoal discharging temperature within a preset safe range; adjusting the air supply amount of the third ventilation pipe according to the monitoring data of the flue gas analyzer to ensure that the combustible components in the charcoal discharging zone are completely burned out and the discharged flue gas meets the clean emission standard.

[0010] Further, the outer pipe wall of the feeding pipe is provided with a heat conduction structure to better utilize the high temperature in the hearth to achieve carbonization of the biomass raw material; the heat conduction structure is a fin provided on the outer pipe wall, the fin being one or a combination of radial fin, axial fin or spiral fin, the fin being capable of strengthening convective and radiative heat transfer by increasing the contact area; and / or, the heat conduction structure makes the total effective heat exchange area of the feeding pipe not less than 1.8 times of the basic outer surface area; and / or, the heat conduction structure includes one or more heat pipes embedded in the pipe wall of the feeding pipe, the evaporation section of the heat pipe being arranged adjacent to the outer wall of the feeding pipe and the condensation section being arranged adjacent to the inner wall of the feeding pipe; and / or, the heat conduction structure is realized by roughening the outer pipe wall of the feeding pipe or applying a high-thermal-conductivity coating.

[0011] Further, the charcoal discharging port is provided with: a star-shaped discharge valve for continuously discharging charcoal; a cooling conveyor arranged downstream of the star-shaped discharge valve for receiving, conveying and cooling the charcoal; the cooling conveyor is a jacketed screw conveyor, and the jacket of the cooling conveyor is connected with a cooling medium circulating mechanism.

[0012] Further, the driving shaft of the star-shaped discharge valve is supported at both ends on an external cooling bearing seat, the external cooling bearing seat comprises a bearing seat shell with a bearing arranged therein and a cooling jacket, the cooling jacket is formed in the bearing seat shell or wrapped outside the bearing seat shell, and the cooling jacket is connected to a cooling medium circulating mechanism; and / or, a blockage prevention device is arranged between the carbonization furnace and the star-shaped discharge valve, the blockage prevention device is an arch breaker or a vibrator; and / or, the star-shaped discharge valve is provided with a third temperature sensor for monitoring the bearing temperature of the star-shaped discharge valve, the third temperature sensor is signal-connected to the control system and is configured to perform the following operations: when the temperature value detected by the third temperature sensor exceeds a first preset threshold value, an alarm signal is sent; and when the temperature value detected by the third temperature sensor exceeds a second preset threshold value higher than the first preset threshold value, the star-shaped discharge valve is controlled to stop.

[0013] Further, the cooling conveyor comprises a plurality of stages of discharge augers connected in series, and the plurality of stages of discharge augers are used for performing gradient cooling and conveying on the discharged charcoal; wherein the first stage of discharge auger is connected to the charcoal discharging port for receiving the discharged charcoal, and the subsequent stages of discharge augers can sequentially convey, cool and homogenize the charcoal; and the last stage of discharge auger is connected to a plurality of bulk bags for simultaneously collecting and packaging the charcoal in multiple channels.

[0014] Further, the rotation speed of each stage of discharge auger is independently adjustable and decreases from the first stage to the last stage; and / or, the cooling conveyor comprises four stages of discharge augers corresponding to four process stages of high-temperature discharging, preliminary cooling, deep cooling and buffer collecting.

[0015] Further, the internal combustion carbonization system based on the whole-process spiral propulsion of the material further comprises an exhaust device connected to the carbonization furnace for discharging the flue gas after combustion; the exhaust device is connected to the carbonization furnace through a metal bellows expansion joint, and the metal bellows expansion joint can compensate the displacement between the carbonization furnace and the exhaust device due to thermal expansion; one end of the metal bellows expansion joint is fixedly connected to the carbonization furnace, and the other end is connected to the exhaust device through a movable pipeline supported by a sliding support to slide with the expansion and contraction of the metal bellows expansion joint.

[0016] Further, the metal bellows expansion joint is an axial compound bellows, and an inner lining layer resistant to high temperature and corrosion is arranged on the inner wall of the metal bellows expansion joint; and / or, the metal bellows expansion joint is wrapped with a heat preservation layer.

[0017] The application also provides an internal combustion carbonization system based on full-process spiral material pushing, which comprises a carbonization furnace, a feeding auger, an ignition device, a first air blower and a second air blower. The carbonization furnace extends linearly along the left-right direction, and is provided with a charcoal discharging port at the right end. The furnace chamber is sequentially formed with a drying preheating zone, a main carbonization self-ignition zone and a burnout charcoal discharging zone along the advancing direction of the material. The feeding pipe of the feeding auger is inserted into the furnace chamber and extends from the drying preheating zone to the burnout charcoal discharging zone. Through the partition design in the furnace chamber and the full-process penetrating layout of the feeding auger feeding pipe, the material is turned, fed and carbonized in the pipe, which completely solves the problems of uneven carbonization and product quality fluctuation caused by static accumulation or simple pushing of the material in the traditional external combustion equipment. At the same time, the internal combustion design allows the pyrolysis gas to self-ignite in the furnace, and the heat directly acts on the feeding pipe and the material, avoiding the heat loss of the external combustion double-wall surface conduction, which can greatly improve the heat utilization rate and realize the system self-circulation without external continuous energy supply, thereby reducing the operation cost. Further, through the double-pipe design of the first air blower, the main combustion air is accurately provided for the main carbonization self-ignition zone through the first air duct to ensure the realization and maintenance of carbonization, and the discharged charcoal is forcibly cooled through the second air duct to avoid the secondary combustion risk caused by the delayed cooling of the traditional equipment. Through the secondary air supply of the second air blower, the residual combustible gas can be completely burned out in the burnout charcoal discharging zone, solving the problems of energy waste and environmental pollution caused by the inefficient combustion or direct discharge of the pyrolysis gas in the traditional equipment. The overall structure overcomes the defects of low thermal efficiency, poor carbonization consistency, high energy consumption and substandard emission of the prior art through the synergy of functional partition, full-process spiral pushing and precise air supply cooling. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 FIG. 1 is a structural schematic diagram of an internal combustion carbonization system based on full-process spiral material pushing provided by the application. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the specific embodiments of the application will be described in detail below in combination with the drawings. In the following description, a large number of specific details are set forth in order to fully understand the application. However, the application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the application, so the application is not limited by the specific embodiments disclosed below.

[0020] The application provides a combustion system for carbonization based on spiral material pushing, which comprises a carbonization furnace 1, a hearth of the carbonization furnace 1 extending linearly along the left-right direction, a carbon discharge port arranged at the right end of the carbonization furnace 1, a drying preheating zone, a main carbonization self-ignition zone and a burnout carbon discharge zone sequentially formed inside the hearth along the advancing direction of the material, a feeding auger 2, a feeding pipe of the feeding auger 2 inserted into the hearth and extending from the drying preheating zone to the burnout carbon discharge zone, so that the outlet of the feeding pipe is close to the carbon discharge port, the feeding auger 2 is used for conveying the biomass raw material, the spiral blade is arranged in the feeding pipe, and the spiral blade stirs during work, so that the material can be turned, fed and carbonized in the feeding pipe, and an ignition device is used for igniting the combustible pyrolysis gas generated in the carbonization furnace 1.

[0021] Specifically refer to Figure 1 In the illustrated embodiment, the carbonization furnace 1 adopts a horizontal horizontal linear configuration, the hearth extends linearly along the left-right direction, and the inside is not physically separated, and the overall structure is adapted to the requirements of continuous material pushing and partitioned carbonization. The right end of the carbonization furnace 1 is provided with a carbon discharge port, and the left end is provided with a perforation, and the feeding pipe of the feeding auger 2 is horizontally inserted into the hearth.

[0022] Continue to refer to Figure 1 The feeding auger 2 is connected to the stock bin, and the stock bin can convey the biomass raw material to the feeding auger 2 through the conveying belt, the bucket elevator and other transportation mechanisms. The left end of the feeding auger 2 is the outlet end, and the outlet is close to the carbon discharge port (such as being suspended directly above the carbon discharge port), so that the material after carbonization can fall into the carbon discharge port after being discharged from the feeding pipe and then be output through the carbon discharge port.

[0023] Specifically, the feeding auger 2 further comprises a spiral blade arranged in the feeding pipe, the spiral blade is accurately matched with the pipe body, and during work, the continuous stirring and pushing force is formed by the rotation of the spiral blade, so that the material in the feeding pipe is in a dynamic state.

[0024] The ignition device is selected from a high-voltage electric igniter or a gas-assisted ignition gun, and is installed on the side wall or the top of the middle section of the hearth, and the ignition end faces the main combustion zone.

[0025] More specifically, the three functional partitions of the hearth are naturally and continuously divided along the material advancing direction. The front section is a drying preheating zone, located on the left side of the hearth, corresponding to the raw material supply end of the feeding auger 2, which can fully utilize the heat transferred from the subsequent area in the hearth to evaporate the moisture of the raw material, laying the foundation for the subsequent carbonization; the middle section is a main carbonization spontaneous combustion zone, located in the central core position of the hearth, which is the key area for the raw material to undergo intense pyrolysis reaction. A large amount of combustible pyrolysis gas is released during this process. This area serves as the core combustion zone, providing continuous heat for pyrolysis reaction and raw material carbonization; the rear section is a burnout and carbon discharge zone, adjacent to the carbon discharge port, which can make the residual combustible gas in the front section fully burn out with the cooperation of the air supplement mechanism (second air blower 4), thereby reducing the emission of pollutants.

[0026] When starting the furnace, first start the ignition device to improve the temperature in the furnace by burning external raw materials; when the temperature in the furnace reaches the preset value, start the feeding auger 2 to push the raw materials into the furnace; combustible pyrolysis gas is generated during the carbonization of the raw materials, and the pyrolysis gas overflows from the right end of the feeding pipe and is ignited; as the combustion continues, the temperature in the furnace gradually rises, and the drying preheating zone starts to dry the newly entered raw materials using the transferred heat, while the burnout and carbon discharge zone simultaneously plays the role of burning out the gas; as the amount of pyrolysis gas increases, the pyrolysis gas can replace the external raw materials; when the temperature in the furnace and the concentration of pyrolysis gas reach the pyrolysis gas self-ignition point, at this time, the ignition device is not needed as the main heat source for heating work, and the pyrolysis gas in the furnace can continue to self-ignite, so that the system enters a self-sustaining operation state. The material is turned, fed and carbonized in the feeding pipe throughout the process, the carbonization products are discharged through the carbon discharge port, and the heat generated by the combustion of pyrolysis gas continuously provides energy for the carbonization process, finally realizing the self-circulation operation of the system.

[0027] Further, the first air blower 3 has an air outlet that is divided into a first ventilation duct 3a and a second ventilation duct 3b. The first ventilation duct 3a is connected to the main carbonization spontaneous combustion zone for providing main combustion air, and the second ventilation duct 3b is connected to the right end of the furnace, opposite the outlet of the feeding pipe, for forcibly cooling the discharged charcoal. The second air blower 4 is connected to the burnout and carbon discharge zone through a third ventilation duct 4a for supplying secondary air to ensure the complete combustion of combustible gas.

[0028] Specifically, refer to Figure 1 In the illustrated embodiment, the first air blower 3 serves both as a main combustion support and a safe cooling for discharging. It delivers main combustion air to the main carbonization spontaneous combustion zone through the first ventilation duct 3a, providing core oxygen for the self-ignition of pyrolysis gas, which is crucial for maintaining the carbonization temperature in the furnace. At the same time, it delivers cold air to the above of the carbon discharge port through the second ventilation duct 3b, directly forcibly cooling the high-temperature discharged charcoal to prevent red charcoal from self-igniting or burning, thereby ensuring the safety of subsequent collection. The preheated air entering the rear section of the furnace can also participate in the burnout process, realizing the integration of cooling and air supply functions.

[0029] The second air blower 4 focuses on combustion enhancement, and through the third air duct 4a, sufficient air is supplied to the combustion and carbon discharge area to ensure that the incompletely combusted gas (such as CO) conducted from the main combustion area obtains sufficient oxygen, realizes full combustion, improves energy utilization, and reduces pollutant emissions.

[0030] It needs to be explained that two air blowers (the first air blower 3 and the second air blower 4) are used instead of one air blower divided into three paths or three air blowers each for one path, in order to adapt to the different air volume requirements and control accuracy of different functions.

[0031] If one air blower is divided into three paths, the pressure and flow requirements of the main combustion air, cooling air, and combustion air are quite different, and a single air blower cannot simultaneously meet the precise control under multiple working conditions, which may lead to unstable main combustion intensity, insufficient cooling effect, or insufficient combustion. If three air blowers are used, independent control can be achieved, but the number of equipment, system complexity, and manufacturing cost will increase, and the extra pipelines and air blowers will occupy more installation space.

[0032] The design of two air blowers realizes the balance of function division and control efficiency. The first air blower 3 focuses on the associated functions of “main combustion + cooling assistance”, and the second air blower focuses on the independent demand of “combustion enhancement”, which can ensure the precise matching of air volume of each pipeline and simplify the system structure.

[0033] It also needs to be explained that the main combustion air refers to the air supplied to the main carbonization self-combustion area, which provides the oxygen required for the combustion of flammable pyrolysis gas generated during carbonization, maintains the self-combustion state to ensure the stable high temperature required for carbonization, and is the energy basis for the self-circulation of the system.

[0034] The secondary air refers to the supplementary air supplied to the combustion and carbon discharge area, which is specifically for the residual flammable gas that has not been completely combusted, and the purpose is to provide sufficient oxygen for its combustion. The core role is to enhance combustion, reduce emissions, and recover waste heat.

[0035] The main combustion air acts on the core carbonization area, directly supporting the self-combustion of pyrolysis gas and temperature maintenance; the secondary air acts on the rear combustion area, focusing on the complete combustion of residual gas, and the air volume of the main combustion air needs to be dynamically matched with the generation amount of pyrolysis gas, and the air volume of the secondary air needs to be adjusted according to the content of the unburned components in the flue gas.

[0036] The three air flows form a synergistic and complementary relationship during the entire carbonization process. The main combustion air of the first air duct 3a can lay the energy foundation by maintaining the pyrolysis gas self-ignition and providing continuous high temperature for carbonization. The cooling air of the second air duct 3b preferentially ensures the safety of discharging, and the subsequent gas flow participating in burnout can also supplement a small amount of oxygen to the rear section to form a functional connection. The secondary air of the third air duct 4a focuses on burnout strengthening, which is used to make up for the oxygen decay of the main combustion air in the rear section of the hearth to ensure the complete combustion of combustible gas. The three air flows cooperate with each other, maintain the energy core of the system self-circulation through the main combustion air, improve the energy utilization rate and environmental protection through the secondary air, and achieve safety cooling and auxiliary air supply through the air of the second air duct 3b, so as to finally realize the multiple goals of carbonization efficiency, product safety and emission standard.

[0037] The internal combustion carbonization system based on the whole-process spiral propulsion of the material provided in the application realizes the whole-process penetration layout of the feeding auger 2 through the partition design in the hearth and the feeding pipe, so that the material is turned, fed and carbonized in the pipe, which completely solves the problems of uneven carbonization and product quality fluctuation caused by the static accumulation or simple pushing of the material in the traditional external combustion equipment. At the same time, the internal combustion design can make the pyrolysis gas self-ignite in the furnace, and the heat directly acts on the feeding pipe and the material, avoiding the heat loss of the double-wall conduction of the external combustion, which can greatly improve the heat utilization rate, realize the system self-circulation without external continuous energy supply, and reduce the operation cost. Further, through the double-pipe design of the first air blower 3, the first air duct 3a can accurately provide the main combustion air for the main carbonization self-ignition zone to ensure the realization and maintenance of carbonization, and the second air duct 3b can forcibly cool the discharged charcoal to avoid the secondary combustion risk caused by the delayed cooling of the traditional equipment. Through the secondary air supply of the second air blower 4, the residual combustible gas can be completely burned out in the burnout and charcoal discharging zone, solving the problems of energy waste and environmental pollution caused by the low-efficiency combustion or direct discharge of the pyrolysis gas in the traditional equipment. Through the cooperation of the functional partition, whole-process spiral propulsion and precise air supply and cooling, the overall structure can overcome the defects of low thermal efficiency, poor carbonization consistency, high energy consumption and non-standard emission of the prior art.

[0038] Optionally, the feeding pipe and the spiral blade of the feeding auger 2 are made of high-temperature-resistant alloy, and the thermal conductivity thereof is not less than 10 W / (m·K).

[0039] It is easy to understand that the feeding pipe and the spiral blade are in the carbonization furnace 1, and the highest temperature in the furnace is above 600 DEG C, and both need to be directly contacted with the high-temperature hot gas flow and the material being carbonized, and at the same time, the heat in the furnace is transmitted to the material in the pipe through heat conduction to ensure the carbonization reaction, therefore, it must be made of high-temperature alloy, which can meet the requirements of structural stability, oxidation resistance and thermal shock resistance in high-temperature environment, and can also resist the wear caused by the overturning and stirring of the material; through the thermal conductivity of not less than 10 W / (m·K), the heat transfer efficiency can also be ensured.

[0040] In practical application, the feeding pipe and the spiral blade can be made of nickel-based alloy or 310S stainless steel. The nickel-based alloy can maintain excellent oxidation resistance, carburizing resistance and high-temperature strength in an environment up to 1100 DEG C, and the thermal conductivity is about 15 W / m·K, which is an ideal choice for high-end applications. 310S stainless steel can be used continuously below 1150 DEG C, has excellent oxidation resistance and thermal shock resistance, and has a thermal conductivity of about 15 W / m·K, and the cost is lower than that of nickel-based alloy, which takes into account performance and economy.

[0041] Optionally, the advancing surface of the spiral blade and / or the inner wall of the feeding pipe are covered with a hard alloy wear-resistant layer formed by surfacing.

[0042] The advancing surface of the spiral blade refers to the stress surface which directly contacts with the biomass raw material and pushes the raw material forward along the feeding pipe during work.

[0043] Since the advancing surface of the spiral blade will continuously rub against the raw material during the stirring and pushing of the material, and the inner wall of the feeding pipe will also be frequently worn due to the overturning and movement of the material, both of these parts are easy-to-wear areas during system operation, and the hard alloy wear-resistant layer can specifically improve the wear resistance of the components, thereby prolonging the service life.

[0044] Specifically, a high-chromium tungsten carbide hard alloy is cladded on the target surface by surfacing process to form a protective layer, wherein the hard alloy is specifically high-chromium tungsten carbide material, which has excellent wear resistance.

[0045] Optionally, the surface of the feeding pipe and / or the spiral blade is subjected to high-temperature aluminizing treatment.

[0046] High-temperature aluminizing treatment refers to the penetration of aluminum element to the surface of the workpiece through high-temperature environment to form a dense Fe-Al intermetallic compound coating.

[0047] The feeding pipe and the helical blade need to work in the high-temperature environment of the carbonization furnace 1 for a long time. The surface thereof is subjected to high-temperature aluminizing treatment. On the one hand, the compact coating formed thereby can resist high-temperature oxidation and hot corrosion, prolong the service life of the components, and on the other hand, the coating can indirectly improve the heat conduction effect of the workpiece surface, make the heat transfer more stable, and better adapt to the high-temperature working condition requirement in the carbonization process of the material.

[0048] Optionally, the feeding auger 2 is provided with a cooling structure at the position outside the hearth for blocking the high temperature in the furnace from being transmitted to the driving components thereof.

[0049] In an embodiment, the cooling structure adopts a water-cooled jacket. The water-cooled jacket is a sandwich sleeve concentrically sleeved with the feeding pipe of the feeding auger 2. The water-cooled jacket is installed between the hearth shell and the driving bearing seat and wraps the part of the feeding pipe exposed outside. The water inlet and outlet are respectively arranged at the two ends of the sandwich. The cold water enters from the end close to the bearing and flows out from the other end close to the hearth, thereby forming counterflow cooling. The two ends of the water-cooled jacket are sealed by double channels by using graphite packing or high-temperature silicone sealing rings, and are fixed by a support without being welded to the feeding pipe to allow thermal expansion. The cooling water source of the water-cooled jacket is connected to the cooling tower circulating water system. The temperature sensor and the electric regulating valve can realize self-adaptive adjustment of the flow. Through sufficient heat exchange of the cooling water in the spiral flow channel, the high temperature transmitted by the feeding pipe is continuously taken away, and the heat conduction to the driving components is prevented.

[0050] In another embodiment, the cooling structure adopts a cooling coil. The copper pipe or stainless steel pipe is tightly coiled at the position of the feeding pipe to be cooled and is fixed by a clamp. The heat exchange between the cooling medium flowing in the pipe and the feeding pipe is used to absorb the heat conducted from the furnace to the exposed feeding pipe and reduce the transmission of the high temperature to the driving components.

[0051] The application does not limit the specific configuration of the cooling structure.

[0052] The setting of the cooling structure can accurately block the transmission of the high temperature in the furnace to the key components such as the driving bearing, avoid the failure of the driving components due to high temperature, and thus ensure the long-term and stable operation of the system.

[0053] Optionally, the edge of the helical blade is provided with an elastic material scraping strip for removing the material adhered to the inner wall of the feeding pipe.

[0054] The elastic material scraping strip is a strip-shaped component made of elastic wear-resistant materials such as fluorine rubber or high-temperature-resistant silicone rubber, which has good flexibility and high-temperature resistance and can adapt to the working environment in the carbonization furnace 1.

[0055] Specifically, the elastic material scraping strip is fixed to the edge of the helical blade by bolts or buckles. After installation, the gap between the elastic material scraping strip and the inner wall of the feeding pipe is controlled within a very small range, so that the elastic material scraping strip is in close contact with the pipe wall and does not affect the normal rotation of the helical blade.

[0056] In the process of spiral blade stirring and propelling material, the elastic scraper strip can scrape off the material residues attached to the inner wall of the feeding pipe in real time, avoiding the coking and clumping of the material due to high-temperature carbonization, and the adhesion to the pipe wall. In this way, not only can the pipeline blockage be prevented and the smoothness of the conveying be affected, but also the cleanliness of the inner wall of the feeding pipe can be ensured, the uniformity of the heat transfer of the pipe wall can be ensured, and the consistency of the carbonization effect of the material can be ensured, while the waste caused by the material residues is reduced, and the service life of the feeding pipe and the spiral blade is prolonged.

[0057] Optionally, the feeding pipe is fixedly arranged in the hearth through a high-temperature-resistant support structure, and the support structure is configured to allow thermal expansion of the feeding pipe.

[0058] In an embodiment, the support structure is a sliding high-temperature-resistant support structure, which includes a fixed base, a sliding support block, and a high-temperature-resistant and wear-resistant gasket. The fixed base is made of high-temperature-resistant cast iron and is fastened to the inner wall of the hearth by bolts. The sliding support block is made of silicon nitride ceramic material, and one side of the sliding support block that is attached to the outer wall of the feeding pipe is processed into an arc-shaped groove. A graphite-based wear-resistant gasket is laid in the arc-shaped groove. Horizontal guide rails are designed between the sliding support block and the fixed base, and an axial sliding gap of 15-20 mm is reserved. When the feeding pipe is heated and elongated under high temperature, it can freely slide along the guide rails to compensate for the thermal expansion by sliding displacement. Meanwhile, the existence of the gasket can reduce the sliding friction loss and ensure the stability of the support.

[0059] In another embodiment, the support structure is an elastic compensation type high-temperature-resistant support structure, which mainly includes a support arm, a high-temperature alloy spring, and an arc-shaped support seat. One end of the support arm is welded to the steel structure of the inner wall of the hearth, and the other end is connected to the arc-shaped support seat through a high-temperature alloy spring. The inner side of the arc-shaped support seat is lined with a high-temperature-resistant silica gel buffer layer and attached to the outer wall of the feeding pipe. The high-temperature alloy spring is made of Inconel alloy material, which has good high-temperature elastic stability. When the feeding pipe thermally expands, it will push the arc-shaped support seat to compress the spring, and the displacement stress generated by thermal expansion will be absorbed by the elastic deformation of the spring. In this way, the feeding pipe is not only fixed and supported, but also allowed to freely stretch and contract through elastic compensation, avoiding deformation and damage caused by thermal expansion and contraction.

[0060] In an embodiment, the first ventilation pipe 3a, the second ventilation pipe 3b, and the third ventilation pipe 4a are each provided with an adjusting valve. The adjusting valve is used to adjust the air supply of the corresponding pipe, so as to realize precise matching of the air volume for carbonization reaction and pyrolysis gas combustion.

[0061] The adjusting valve is an electric flow control component adapted to the ventilation pipe, which has the function of precisely adjusting the opening degree and can control the air volume by changing the airflow flow area in the pipe.

[0062] Specifically, three sets of regulating valves are installed on the first ventilation pipeline 3a, the second ventilation pipeline 3b and the third ventilation pipeline 4a respectively. During operation, the air supply of each pipeline is precisely controlled by adjusting the opening of the regulating valve according to the progress of the carbonization reaction and the actual demand of the pyrolysis gas combustion, so as to accurately match the oxygen demand of the main carbonization spontaneous combustion zone and the combustion of the pyrolysis gas, and to ensure sufficient combustion and stable and efficient carbonization process.

[0063] Optionally, the carbonization system further comprises: a first temperature sensor for monitoring the temperature of the main carbonization spontaneous combustion zone; a second temperature sensor for monitoring the temperature of the carbon discharge port; a flue gas analyzer for monitoring the composition of the flue gas discharged from the carbonization furnace 1; a control unit electrically connected with the first temperature sensor, the second temperature sensor and the flue gas analyzer, and signal connected with the actuator of the regulating valve, and the control unit is configured to execute the following control logic: the first ventilation pipeline 3a is closed loop adjusted according to the monitoring data of the first temperature sensor to stabilize the temperature of the main carbonization spontaneous combustion zone within the preset range; the second ventilation pipeline 3b is closed loop adjusted according to the monitoring data of the second temperature sensor to control the carbon discharge temperature within the preset safety range; the third ventilation pipeline 4a is closed loop adjusted according to the monitoring data of the flue gas analyzer to ensure that the combustible components in the carbon discharge zone are completely burned out and the discharged flue gas meets the clean emission standard.

[0064] The first temperature sensor, the second temperature sensor, the flue gas analyzer and the control unit constitute a closed loop control mechanism of the system, and the four are closely associated through electrical signals and signal connection. The three monitoring components serve as data acquisition ends for real-time capture of key working condition parameters of the system, and the control unit serves as a central processing end for receiving and analyzing these parameters and sending control instructions to the regulating valve actuators of the ventilation pipelines to realize the cooperation of "monitoring-analysis-control".

[0065] Specifically, the first temperature sensor is used to monitor the temperature of the main carbonization spontaneous combustion zone in real time and feed back the data to the control unit. If the temperature is lower than the preset optimal carbonization range (e.g. 550-750℃), the control unit instructs the regulating valve of the first ventilation pipeline 3a to open, thereby increasing the supply of primary combustion air and intensifying the combustion to raise the temperature. If the temperature is too high, the valve is closed to suppress the combustion and lower the temperature. Through the dynamic matching of the air volume and the feeding speed (gas production rate), the stable supply of heat required for carbonization is ensured.

[0066] The second temperature sensor is used to monitor the temperature of the carbon discharge port in real time. When it is detected that the temperature exceeds the preset safety range (e.g. 200-500℃), the control unit drives the regulating valve of the second ventilation pipeline 3b to open, thereby increasing the cooling air volume and reducing the temperature of the carbon material. If the temperature of the rear section of the furnace is too low and there is unburned gas, the valve can be appropriately opened to supplement the auxiliary air for combustion. If the temperature of the rear section is too high, the valve is closed to avoid excessive combustion and heat loss.

[0067] The flue gas analyzer is used to detect the content of O2, CO and other components in the discharged flue gas in real time. When the CO content is high and the O2 content is low, the control unit instructs the regulating valve of the third ventilation pipeline 4a to open wide, thereby increasing the supply amount of secondary air and promoting the complete combustion of unburned gas. If the O2 content is too high, the valve is closed to reduce the heat loss caused by the introduction of cold air, so as to ensure the balance between the complete combustion effect and the thermal efficiency.

[0068] Through the cooperation of the first temperature sensor, the second temperature sensor, the flue gas analyzer and the control unit, on the one hand, the main combustion air amount can be accurately controlled, so that the temperature of the main carbonization self-ignition zone is stabilized in the best interval, solving the problem of large temperature fluctuation and incomplete carbonization of the traditional equipment. On the other hand, by regulating the temperature of the carbon discharge port, the carbon discharge temperature can be controlled within a safe range, avoiding the risk of secondary combustion of high-temperature charcoal. At the same time, by optimizing the secondary air supply through the feedback of flue gas components, the content of combustible components in the flue gas can be reduced to the minimum, so as to realize clean emission. The overall closed-loop control makes the system air volume accurately match the carbonization reaction and the complete combustion demand, which can maximize the release of heat and improve the heat utilization rate, and at the same time, reduce energy waste, ensuring the efficient, safe and stable operation of the system.

[0069] Optionally, a heat conduction structure is arranged on the outer wall of the feeding pipe, so as to better utilize the high temperature in the hearth to realize carbonization of the biomass raw material.

[0070] The base outer surface area of the feeding pipe is limited, and the heat capture and transmission efficiency is insufficient by relying on the heat conduction of the pipe wall itself. By arranging the heat conduction structure, the convective and radiative heat exchange between the feeding pipe and the high-temperature environment in the hearth can be strengthened, the heat transfer effect can be improved, the wet raw material can be quickly dried during the advancing process in the feeding pipe, and a good foundation can be laid for the subsequent intense pyrolysis reaction in the main carbonization self-ignition zone, so as to ensure the stability and efficiency of the carbonization process.

[0071] In an embodiment, the heat conduction structure is a fin arranged on the outer wall of the pipe, and the fin is one or a combination of radial fins, axial fins or spiral fins. The fin can strengthen the convective and radiative heat exchange by increasing the contact area.

[0072] Specifically, the fin is made of heat-resistant stainless steel or aluminized steel, which is compatible with the base pipe material of the feeding pipe. By greatly increasing the contact area between the feeding pipe and the high-temperature gas in the hearth, the convective and radiative heat exchange can be strengthened, and the heat transfer efficiency can be improved.

[0073] More specifically, the radial fins are straight fin-shaped structures extending radially outward along the outer wall of the feeding pipe, evenly distributed in a radial pattern, and easy to weld and fix. The axial fins are long strip-shaped structures extending parallel to the axial direction of the feeding pipe, consistent with the axial direction of the pipe body, and simple and regular in structure. The spiral fins are fin-shaped structures spirally wound along the outer wall of the feeding pipe, forming a continuous spiral angle with the pipe body and fitting the pipe wall. Among them, the radial fins can maximize the expansion of the heat exchange area, the axial fins facilitate processing and installation, and the spiral fins can strengthen the gas turbulence effect, reduce the surface dust, and ensure the stability of heat exchange in long-term use; the three configurations can be used alone or in combination to adapt to different heat exchange needs.

[0074] In another embodiment, the heat-conducting structure makes the total effective heat exchange area of the feeding pipe not less than 1.8 times of the basic outer surface area.

[0075] The conventional feeding pipe relies only on the basic outer wall for heat exchange, and the area is limited, which cannot quickly and fully remove water during the advancement of the raw material, easily causing incomplete carbonization and product quality fluctuations, and often needs to extend the furnace to ensure the heat exchange effect.

[0076] The setting of the heat-conducting structure and the requirement that the total effective heat exchange area is not less than 1.8 times of the basic outer surface area helps to make full use of the high-temperature heat in the furnace, realizing rapid drying and efficient carbonization.

[0077] The value of 1.8 times is obtained through thermal calculation and experimental verification in combination with the moisture content of the raw material (30%-50%), the feeding speed, the high-temperature environment of the furnace (400-800℃), and the basic size of the feeding pipe, etc. At this value, it not only meets the heat transfer demand of drying and carbonizing wet raw materials, but also avoids the complexity of structure caused by excessive heat exchange area (such as fin dust and high cost), which is the optimal value considering effect, feasibility and economy.

[0078] In one embodiment, radial fins are welded on the outer wall of the feeding pipe, 310S heat-resistant stainless steel is selected to make fins with a height of 50mm and a thickness of 8mm, and one fin is arranged every 30° along the circumference of the pipe and one circle is arranged every 150mm along the axial direction. Through the three-dimensional extension of the fins, the heat exchange area is greatly expanded, and the total effective heat exchange area reaches 2 times of the basic outer surface area.

[0079] In another embodiment, sandblasting roughening treatment is performed on the outer wall of the feeding pipe, and then a 0.5mm thick high-thermal-conductivity ceramic coating is sprayed, and at the same time, short strip-shaped auxiliary heat-conducting protrusions (height 30mm, length 100mm) are welded at intervals. Through the combination of rough surface, high-thermal-conductivity coating and auxiliary protrusions, the total effective heat exchange area reaches 1.9 times of the basic outer surface area, which not only simplifies the structure but also meets the heat exchange requirements.

[0080] In yet another embodiment, the heat conducting structure comprises one or more heat pipes embedded in the wall of the feeding pipe, with the evaporation section of the heat pipe adjacent to the outer wall of the feeding pipe and the condensation section adjacent to the inner wall of the feeding pipe.

[0081] A heat pipe is a sealed and vacuumized metal pipe with a capillary structure such as metal sintered powder or metal wire mesh lining the inner wall and filled with working liquid such as water, acetone, ammonia or liquid metal. Its equivalent thermal conductivity can reach hundreds to thousands of times of that of good conductors such as copper and silver, and it can spontaneously transfer large amounts of heat under a small temperature difference without external power.

[0082] Specifically, the evaporation section of the heat pipe refers to the end that receives heat, and when heat is applied to it, the working liquid in the pipe will rapidly absorb heat and evaporate into steam. The condensation section refers to the end that releases heat, and when the steam reaches this end, it will release latent heat and re-condense into liquid, and then automatically flow back to the evaporation section through the capillary structure, forming a circulating heat transfer.

[0083] By placing the evaporation section of the heat pipe adjacent to the outer wall of the feeding pipe and the condensation section adjacent to the inner wall of the feeding pipe, the outer wall of the feeding pipe is in a high-temperature environment in the furnace, and the evaporation section near the outer wall can maximize the capture of radiant heat from the furnace and convective heat from the high-temperature flue gas, providing sufficient heat source for the heat transfer cycle. The condensation section near the inner wall can directly release the captured heat to the biomass raw material inside the feeding pipe, achieving directional and low-loss transfer of heat from the outer wall to the inner wall.

[0084] This design takes advantage of the extremely high efficiency of heat transfer by phase change of the heat pipe, which can quickly "transport" the heat from the furnace to the inside of the raw material. The isothermic nature of the heat pipe ensures uniform temperature on the inner wall of the feeding pipe, avoiding local overheating or insufficient heating of the raw material. The structure is compact and highly reliable, maximizing the recovery of furnace waste heat for raw material drying and improving system energy efficiency.

[0085] In another embodiment, the heat conducting structure is achieved by roughening the outer wall of the feeding pipe or applying a high thermal conductivity coating.

[0086] Roughening the outer wall of the feeding pipe involves targeted processing, such as sandblasting, thread rolling, or creating small pits and bumps on the surface of the pipe wall, which can increase the actual surface area and roughness of the pipe wall.

[0087] The high thermal conductivity coating is a ceramic coating with high emissivity and high thermal conductivity, such as a silicon carbide coating, which is applied to the surface of the outer wall of the feeding pipe through a spraying process.

[0088] In this way, the increased surface area due to roughening and the excellent heat radiation absorption and heat conduction capabilities of the high thermal conductivity coating can be used to synergistically improve the heat exchange efficiency between the feeding pipe and the high-temperature environment in the furnace, thereby ensuring the efficiency and uniformity of the carbonization process.

[0089] Optionally, the charcoal discharging port is provided with a star-shaped discharge valve 11 for continuously discharging charcoal, and a cooling conveyor 12 downstream of the star-shaped discharge valve 11 for receiving, conveying and cooling charcoal. The cooling conveyor 12 is a jacketed screw conveyor, and the jacket of the cooling conveyor 12 is connected to a cooling medium circulating mechanism.

[0090] The star-shaped discharge valve 11 is a high-temperature-resistant component with mechanical air locking and quantitative conveying functions. The shell and blades of the star-shaped discharge valve 11 are made of ZG40Cr25Ni20 heat-resistant cast steel, and the edges of the blades can be hardfaced with wear-resistant hard alloy. The end part is equipped with an external bearing seat (the bearing is moved to the outside of the valve body away from the high-temperature zone through a long shaft). The gap between the blade and the shell is precisely controlled to be less than 0.5 mm. The driving system is composed of a variable frequency motor, a speed reducer and a chain transmission, and the driving motor is connected to a control system.

[0091] For details, please refer to Figure 1 In the illustrated embodiment, the star-shaped discharge valve 11 is installed at the charcoal discharging port of the carbonization furnace 1. During use, the blades are driven to rotate by a variable frequency motor, and the rotation speed can be automatically adjusted according to the temperature, pressure or feeding speed in the carbonization furnace, so as to realize continuous discharge of charcoal.

[0092] The star-shaped discharge valve 11 can ensure stable and continuous discharge of charcoal while reducing the leakage of gas in the furnace through the precisely controlled blade gap, thereby maintaining stable working conditions in the furnace.

[0093] For details, please refer to Figure 1 The cooling conveyor 12 is a jacketed screw conveyor downstream of the star-shaped discharge valve 11. The core structure is a conveying auger with a sandwiched layer (a spiral blade is arranged in the conveying cylinder), and the sandwiched layer is connected to a cooling medium circulating mechanism.

[0094] The cooling conveyor 12 is used to receive high-temperature charcoal discharged from the star-shaped discharge valve 11, and can push the charcoal forward along the conveying direction through the rotation of the spiral blade. At the same time, the cooling medium continuously circulates in the sandwiched layer of the jacket, and efficiently exchanges heat with the charcoal in the conveying cylinder. In this way, on the one hand, the continuous conveying of charcoal can ensure the coherence of the whole carbonization system, and on the other hand, the high-temperature charcoal can be cooled simultaneously during the conveying process. By rapidly reducing the temperature of the charcoal, secondary combustion of the charcoal due to high temperature can be avoided, thereby ensuring the safety of subsequent collection and packaging. The jacketed structure of the cooling conveyor 12 can ensure uniform and efficient cooling, and maintain stable product quality of the charcoal.

[0095] Optionally, the driving shaft of the star-shaped discharge valve 11 is supported at both ends on an external cooling bearing seat. The external cooling bearing seat includes a bearing seat shell with a bearing and a cooling jacket formed in or wrapped around the bearing seat shell. The cooling jacket is connected to a cooling medium circulating mechanism.

[0096] The external cooling bearing seat is a bearing support structure that completely separates the bearing, seal, and lubrication system from the valve body of the star-shaped discharge valve 11. It is connected to the rotor impeller inside the valve body through a long heat-resistant steel shaft, which acts as a thermal bridge blocker to attenuate heat conduction. The bearing seat shell is made of cast iron or cast steel, and has high-temperature-resistant bearings inside. It is equipped with an inner lip seal (to prevent carbon powder from entering) and an outer dust seal (to prevent lubricating grease from leaking and external dust from entering). It also has a lubrication system with an oil filler and a waste grease discharge channel.

[0097] A cooling jacket is provided on the bearing seat shell. The cooling jacket is a closed cooling cavity formed by a sandwich or coil winding. Compressed air (air cooling) or circulating cooling water (water cooling is preferred) can be introduced. The cooling medium flows in through the water inlet (or air inlet) and circulates around the bearing seat, and finally flows out through the water outlet (or air outlet). In the process, it continuously removes the heat conducted along the long shaft to the bearing seat. In this way, the bearing operating temperature can be stably controlled below the safety threshold (such as 80°C), avoiding high temperature leading to bearing and lubricating grease failure. At the same time, in cooperation with the sealing and lubrication system, the bearing can be ensured to operate reliably and reliably in a clean and suitable temperature environment for a long time.

[0098] Optionally, a anti-blocking device is provided between the carbonization furnace 1 and the star-shaped discharge valve 11. The anti-blocking device is an arch breaker or a vibrator.

[0099] The carbonized charcoal is prone to form a material bridge in the connection area between the charcoal discharge port and the star-shaped discharge valve 11, which may cause the charcoal discharge channel to be blocked, affecting the continuous operation of the system, so an anti-blocking device needs to be provided.

[0100] The arch breaker (such as an air cannon) is a pneumatic or electric structure, installed inside the charcoal discharge port or on the upper chamber of the star-shaped discharge valve 11, and releases an impact force instantaneously through regular action to directly break the arch structure formed by the material accumulation; the vibrator is also installed in the connection area, and keeps the material in a loose state through continuous or regular vibration to avoid mutual adhesion and accumulation.

[0101] The anti-blocking device can specifically solve the problem of material blockage, ensure the smoothness of the charcoal discharge channel, and ensure the continuous discharge of charcoal.

[0102] Optionally, the star-shaped discharge valve 11 is provided with a third temperature sensor for monitoring the bearing temperature of the star-shaped discharge valve 11. The third temperature sensor is signal-connected with the control system and is configured to perform the following operations: when the temperature value detected by the third temperature sensor exceeds a first preset threshold, an alarm signal is sent; when the temperature value detected by the third temperature sensor exceeds a second preset threshold higher than the first preset threshold, the star-shaped discharge valve 11 is controlled to stop.

[0103] The third temperature sensor can be a Pt100 platinum thermal resistor, which is installed in a radial temperature measurement blind hole (the hole bottom is 1-3 mm away from the surface of the bearing outer ring) on the bearing seat shell of the star-shaped discharge valve 11, directly above or on the side of the bearing bearing area. The temperature measurement probe is inserted into the hole and high-temperature heat-conducting silicone grease is injected to ensure heat conduction. Then, the spring compression device or locking sleeve is used for fixation. The sensor lead is connected to the bearing seat side junction box through a high-temperature resistant cable to avoid contact with rotating parts.

[0104] The third temperature sensor is connected to the control system. Two temperature thresholds are set in advance. When the detected bearing temperature exceeds the first preset threshold (e.g. 85℃), the control system issues an audible and visual alarm. When the temperature exceeds the second preset threshold higher than the first preset threshold (e.g. 95℃), the control system automatically triggers the interlocking logic to immediately stop the drive motor of the star-shaped discharge valve 11, and can also send a speed reduction or shutdown signal to the upstream equipment.

[0105] In this way, the lubrication state of the bearing and the running condition of the machine can be monitored in real time, early fault warning is realized, and maintenance personnel can accurately troubleshoot problems. At the same time, through two-stage safety protection, catastrophic damage such as bearing "burning" and shaft neck injury is avoided, and long-term accumulated temperature data can also support predictive maintenance, changing fault repair to planned replacement, greatly improving the reliability, safety and stability of production plans of equipment operation.

[0106] In an embodiment, the cooling conveyor 12 includes a plurality of stages of discharge augers connected in series, and the plurality of stages of discharge augers are used for stage-by-stage cooling and conveying of the discharged charcoal; wherein a first stage of discharge augers is connected to the charcoal discharge port and used for receiving the discharged charcoal, and the subsequent stages of discharge augers can sequentially convey, cool and homogenize the charcoal.

[0107] For details, please refer to Figure 1 In the illustrated embodiment, four stages of discharge augers are arranged in series downstream of the carbonization furnace 1, and the four discharge augers are sequentially connected and constitute the cooling and conveying structure 12. The first stage of discharge augers is directly connected to the charcoal discharge port to receive the just discharged high-temperature charcoal, and the subsequent stages of discharge augers sequentially receive the charcoal conveyed by the previous stage, forming a continuous conveying and cooling link.

[0108] The reason for designing the plurality of stages of discharge augers in series is to achieve multiple technical advantages through stage-by-stage processing, avoiding direct contact of high-temperature red charcoal with air or ordinary equipment to cause fire. In a specific embodiment, temperature control and fire extinguishing are completed in the first stage to ensure safety, and the charcoal is then cooled by the subsequent augers in stages to reduce excessive pulverization of the charcoal due to thermal stress and control the degree of contact with oxygen to maintain fixed carbon content and structure. Limiting the extreme high-temperature impact to the first stage also protects the subsequent equipment and reduces manufacturing costs and maintenance costs.

[0109] The cooling intensity of each stage of the screw conveyor can be independently adjusted to accurately control the cooling curve to adapt to different raw materials or process requirements, thereby improving process controllability. The step-by-step cooling refers to a cooling method that gradually reduces the temperature of charcoal according to the process stage, and the cooling intensity of each stage can be adjusted accordingly. The homogenization refers to making the temperature distribution and particle size of the charcoal more uniform during multi-stage conveying and cooling, thereby ensuring the consistency of product quality.

[0110] Optionally, the last stage of the discharge screw conveyor is connected with a plurality of bulk bags 13, which can simultaneously perform multi-channel collection and packaging of charcoal.

[0111] Specifically, refer to Figure 1 In the illustrated embodiment, the discharge end of the last stage of the discharge screw conveyor is provided with four shunt structures, and each shunt channel is connected with a bulk bag 13. The charcoal after multi-stage step-by-step cooling and homogenization reaches the end under the action of the screw pushing of the last stage of the discharge screw conveyor, and is then uniformly distributed to each bulk bag 13 through the shunt structure, thereby completing the collection and packaging of charcoal.

[0112] The last stage of the discharge screw conveyor continuously supplies material through its own screw conveying power, and its multi-channel shunt structure divides the single conveying path into multiple parallel channels, each of which precisely docks with a bulk bag 13. Without interrupting the conveying, charcoal can be filled into multiple bulk bags 13 at the same time, thereby realizing the synchronous cooperation of single-stage screw conveyor and multi-bag packaging.

[0113] The synchronous work of the plurality of bulk bags 13 can greatly improve the efficiency of charcoal collection and packaging, avoid material accumulation and process interruption caused by single-channel packaging, adapt to the continuous discharge demand of large-scale carbonization production, reduce the frequency of manual bag changing, save labor costs, ensure the filling amount and quality consistency of each bag of charcoal, and improve the standardization and practicality of the packaging link.

[0114] Optionally, the screw rotation speed of each stage of the discharge screw conveyor is independently adjustable and decreases from the first stage to the last stage.

[0115] The screw rotation speed of the discharge screw conveyor decreases from the first stage to the last stage, so that it accurately cooperates with the function of step-by-step cooling. The front end uses high speed to deal with high temperature materials to ensure safety, the middle and rear sections gradually reduce the speed to enhance the heat exchange efficiency, and the end uses low speed to stabilize the material flow to adapt to packaging, thereby forming an optimized process logic of "fast evacuation - sufficient cooling - stable distribution", reducing the mechanical crushing and pulverization of biomass charcoal, and improving the product quality.

[0116] In a specific embodiment, the specific screw rotation speed of the fourth-stage discharging auger can be set as: the first stage 15-20 r / min, because it needs to receive high-temperature red carbon above 600°C, high rotation speed can quickly disperse the material, break up the material layer, increase the contact efficiency with the cooling medium, realize rapid initial cooling and fire extinguishing, and avoid accumulation of heat to cause smoldering; the second stage 12 r / min, the third stage 8 r / min, at this time the material temperature has been reduced to below 300°C, reducing the rotation speed can prolong the residence time of the material in the auger, ensuring sufficient heat exchange with the water cooling jacket, realizing deep cooling and uniform temperature; the fourth stage 5-8 r / min, the material is close to normal temperature, low rotation speed can convert fluctuating material flow into smooth material flow, adapt to the precise dispensing requirements of multi-channel packaging, and at the same time reduce the mechanical crushing of brittle carbon, which can also act as a buffer bin to smooth the difference in process rhythm.

[0117] The screw rotation speed of each stage of the discharging auger is independently adjustable to flexibly adapt to different biomass raw materials, moisture content or process requirements. Specifically, the rotation speed of single-stage or multi-stage discharging auger can be adjusted according to actual working conditions (such as material temperature, cooling effect, packaging rhythm) to ensure that the effects of rapid cooling, sufficient cooling, stable packaging and other links meet the standards.

[0118] Optionally, the cooling conveyor 12 includes four-stage discharging augers corresponding to high-temperature discharging, preliminary cooling, deep cooling and buffer collection four process stages.

[0119] The high-temperature discharging stage refers to a process stage that receives 500-800°C high-temperature carbonization products discharged from the carbonization furnace discharge port and simultaneously performs controllable preliminary cooling, the core of which is to eliminate red carbon fire; the preliminary cooling stage undertakes the main cooling task and is used to cool the material to below 100-500°C; the deep cooling stage (homogenization and buffer stage) is a process stage with material temperature and humidity homogenization and process buffering as the core; the buffer collection stage (metering and shunt packaging stage) is the final process stage that quantitatively delivers and shunts the finished carbon after cooling and homogenization to multiple packaging ports.

[0120] The reason for being divided into four stages is that it can sequentially and progressively adapt to the processing requirements of high-temperature carbon, avoid the direct entry of red carbon with extremely high temperature into subsequent equipment and cause safety hazards, and through segmented cooling, it can ensure sufficient and gentle cooling, thereby avoiding material pulverization due to thermal stress, and at the same time, through homogenization and buffering, it can balance the flow fluctuation between the previous continuous discharging and the subsequent intermittent packaging, so as to realize continuous and stable operation of the system and further improve the consistency of product quality.

[0121] In a specific embodiment, the first-stage discharge auger (high-temperature discharge section) is made of heat-resistant material, equipped with a light water-cooled jacket or air-cooled structure, has a relatively short length, and has a spiral rotation speed of 15-20 r / min. The core is to quickly disperse high-temperature materials and cool them to 300-400℃, while having a certain sealing effect. The second-stage discharge auger (preliminary cooling section) is provided with a high-efficiency water-cooled jacket or dense air-cooled fins, has a relatively long length to ensure sufficient residence time, and has a spiral rotation speed of about 12 r / min. The focus is to achieve deep cooling to below 100℃. The third-stage discharge auger (deep cooling section) pays more attention to the stability of stirring and conveying, and the cooling structure is auxiliary or does not need active cooling. The length is moderate, the spiral rotation speed is about 8 r / min, and the main function is to realize material temperature homogenization and flow buffering. The fourth-stage discharge auger (buffering and collecting section) is equipped with a rotary distributor or a multi-channel flow divider, has a spiral rotation speed of 5-8 r / min, can achieve rough metering by adjusting the rotation speed, and can uniformly distribute the finished carbon to multiple bulk bags 13 to realize continuous and quantitative packaging.

[0122] The internal combustion carbonization system based on the whole-process spiral propulsion of materials provided in the application further comprises an exhaust device 5 communicating with the carbonization furnace 1 for discharging the flue gas after combustion.

[0123] In an embodiment, the exhaust device 5 is a high-temperature-resistant pipe chimney, which is a vertically arranged tubular structure made of high-temperature-resistant material and communicating with the flue gas outlet of the carbonization furnace 1. The core function is to guide the flue gas after combustion to be discharged to a high altitude to avoid the accumulation of flue gas around the equipment, and to enhance the exhaust power by means of the height difference to ensure smooth airflow in the furnace chamber and maintain a stable gas pressure environment required for carbonization and combustion.

[0124] In another embodiment, the exhaust device 5 is an exhaust pipeline with a purification module, specifically a pipeline structure equipped with a high-temperature-resistant filter layer and a desulfurization and denitrification component. One end is connected to the carbonization furnace 1, and the other end extends to the outdoor or a designated discharge point. The function is to remove dust particles in the flue gas through the filter layer and reduce the content of harmful gases through the desulfurization and denitrification component while discharging the flue gas, to ensure that the flue gas meets the clean emission standard and to avoid environmental pollution. The pipeline structure can be flexibly adapted to different installation scenarios.

[0125] In an embodiment, the exhaust device 5 communicates with the carbonization furnace 1 through a metal bellows expansion joint, which can compensate for the displacement between the two due to thermal expansion. One end of the metal bellows expansion joint is fixedly connected to the carbonization furnace 1, and the other end is connected to the exhaust device 5 through a movable pipeline supported by a sliding support to slide with the expansion and contraction of the metal bellows expansion joint.

[0126] When the carbonization furnace 1 is in operation, the length of the furnace body may increase (up to tens of millimeters) due to the high temperature inside the furnace, accompanied by slight radial jumping and end drop. The exhaust device 5 (such as a chimney) is fixed to the ground, and the relative position between the two will change due to the temperature difference.

[0127] The metal bellows expansion joint is an axial compound bellows structure component made of 316L or Inconel 625 heat-resistant stainless steel. The inner wall of the pipe is provided with a high-temperature-resistant and corrosion-resistant lining. Its core feature is good axial expansion, and it can withstand a small amount of lateral deviation and angular deflection. It can precisely absorb the axial displacement between the carbonization furnace 1 and the exhaust device 5 due to thermal expansion through the elastic deformation of its bellows structure, while also adapting to the slight overall displacement of the furnace body, avoiding stress accumulation caused by rigid connection.

[0128] It needs to be explained that although the metal bellows expansion joint has the ability to deform in axial expansion, radial deflection, and can compensate for thermal expansion displacement, there are clear limits to its own compensation amount and the load it can withstand. If the two ends are directly rigidly fixed to the carbonization furnace 1 and the exhaust device 5, problems may occur. For example, when the carbonization furnace 1 is running at high temperature, the furnace body will not only produce axial thermal elongation, but also may appear slight radial swinging or deflection due to uneven heating. The displacement form and amplitude of the two are difficult to completely match, and the exhaust device 5 is usually fixed and installed, with a relatively stable position. If the two ends are rigidly fixed, the swinging or deflection force of the furnace body will be directly transmitted to the metal bellows expansion joint, causing it to bear additional lateral force or torque for a long time, far exceeding its designed bearing range, which can easily lead to fatigue cracking of the bellows and shedding of the weld, greatly shortening the service life.

[0129] Therefore, the addition of a movable pipe and the use of a sliding support can optimize the stress state of the metal bellows expansion joint. Specifically, one end of the metal bellows expansion joint is fixedly connected to the flange short pipe of the exhaust port of the carbonization furnace 1 (this end can move synchronously with the furnace body), and the other end is connected to the movable pipe through a flange. The movable pipe is connected to the exhaust device 5 through flexible joints, hinged structures, or other movable joints, thereby cutting off the transmission path of the furnace body swinging or deflection. At the same time, the movable pipe is supported by an independent low-friction sliding support and can freely slide with the expansion joint. When installed in a cold state, it can also be pre-stretched or pre-compressed according to the type of expansion joint and the working temperature.

[0130] The core reason why the movable pipeline is not afraid of the transmission of lateral force or torque of the furnace body is the guiding constraint design and load decomposition logic of the sliding support of the movable pipeline. On the one hand, the movable pipeline is supported by the sliding support, which only bears the weight of the pipeline in the vertical direction and allows the pipeline to freely slide in the axial direction, but does not limit the small radial displacement. When the furnace body swings or deflects due to thermal deformation or rotation, the metal bellows expansion joint will first absorb part of the displacement, and the remaining small radial force will be converted into an axial sliding trend through the sliding of the movable pipeline, rather than a rigid torque or lateral load. On the other hand, the flexible transition connection between the movable pipeline and the exhaust device 5 can eliminate the residual force that may be transmitted, avoid the accumulation of force, and at the same time, the movable pipeline itself is usually made of a pipe material with good rigidity, and its bending stiffness is sufficient to withstand the small lateral force transmitted by the furnace body, and will not be deformed or damaged due to long-term stress. This design allows the metal bellows expansion joint to focus on bearing the axial expansion and contraction compensation, and the movable pipeline is responsible for eliminating the radial disturbance, which helps to ensure the stability of the entire exhaust system under complex working conditions.

[0131] During the exhaust process, the movable pipeline can freely slide on the sliding support along with the expansion and contraction of the metal bellows expansion joint, which can not only meet the displacement compensation requirements of the axial thermal expansion of the furnace body, but also eliminate the lateral force generated by the radial swing of the furnace body, so that the metal bellows expansion joint only bears the axial expansion and contraction deformation that it is good at, avoiding bearing additional torque or lateral load, thereby ensuring the sealing performance and structural integrity, and prolonging the stable operation period of the entire exhaust system.

[0132] It also needs to be explained that the reason for adopting the design of "one end fixed and the other end sliding" for the metal bellows expansion joint is that the fixed end can ensure the sealing and stability of the connection between the expansion joint and the furnace body, avoiding smoke leakage and damaging the pressure balance in the furnace; the sliding end cooperates with the sliding support and the movable pipeline to provide sufficient space for the expansion and contraction of the expansion joint, so that it can smoothly absorb the thermal expansion displacement and effectively offset the relative movement between the carbonization furnace 1 and the fixed exhaust device 5, avoiding problems such as flange leakage, weld cracking, chimney skewing or furnace deformation caused by thermal stress, reducing the thermal fatigue damage caused by high-temperature circulation, and ensuring long-term stable operation of the system.

[0133] Optionally, the metal bellows expansion joint is an axial multi-wave bellows pipe, and the inner wall of the pipe is provided with a high-temperature-resistant and corrosion-resistant inner lining.

[0134] The axial multi-wave bellows pipe is a metal bellows expansion joint with a multi-wave structure, which can not only efficiently absorb the axial thermal expansion displacement between the carbonization furnace 1 and the exhaust device 5, but also adapt to a small amount of lateral displacement and angular deflection, adapting to the comprehensive displacement requirements of the furnace body during operation.

[0135] The high-temperature-resistant and anti-corrosion inner lining layer is arranged because the flue gas discharged by the carbonization furnace has a temperature of 400-600 DEG C and contains acidic components, water vapor and fine carbon powder particles. These substances can cause high-temperature oxidation, chemical corrosion and erosion wear of the metal body of the corrugated pipe. The inner lining layer can prevent the high-temperature gas from directly contacting the metal, prevent particle erosion, reduce air flow resistance and turbulence, and prolong the service life of the expansion joint.

[0136] Specifically, the inner lining layer can be made of flexible materials such as ceramic fiber woven cloth or alloy foil lining. The flexible inner lining is installed on the inner side of the corrugated pipe and closely adheres to the inner wall of the corrugated pipe, thereby forming a protective barrier without affecting the stretching and deformation function of the corrugated pipe and achieving targeted protection.

[0137] Optionally, the metal corrugated pipe expansion joint is coated with a thermal insulation layer.

[0138] The flue gas discharged by the carbonization furnace has a temperature of 400-600 DEG C. Direct exposure of the metal corrugated pipe expansion joint to the environment will result in a large amount of heat loss, and the low temperature on the outside is easy to cause the water vapor and acidic components in the flue gas to condense and form corrosive media, and the high-temperature surface may cause burns to personnel. Therefore, the thermal insulation layer needs to be arranged to solve these problems.

[0139] The thermal insulation layer can be made of high-temperature-resistant thermal insulation materials such as ceramic fiber cotton and rock wool. When constructing, the thermal insulation material is tightly wrapped on the outer surface of the metal corrugated pipe expansion joint and the connecting pipe, and then fixed with high-temperature-resistant straps. In some scenarios, a protective shell is also installed on the outside to prevent the thermal insulation material from falling off or being damaged.

[0140] The arrangement of the thermal insulation layer can reduce the heat loss of the system, improve the energy utilization rate, maintain the working temperature of the corrugated pipe within the design range, avoid condensation corrosion, prolong the service life of the expansion joint, and also isolate the high-temperature surface to prevent burns to personnel and ensure safe operation.

[0141] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An internal combustion carbonization system based on a spiral propulsion system for the entire material flow, characterized in that, include: Carbonization furnace (1), the furnace chamber of the carbonization furnace (1) extends in a straight line in the left and right direction, and a carbon discharge port is provided at its right end. The furnace chamber is formed in sequence along the material's forward direction as a drying and preheating zone, a main carbonization and self-ignition zone, and a burnout and carbon discharge zone. Feeding auger (2), the feeding pipe of the feeding auger (2) is inserted into the furnace and extends from the drying and preheating zone to the burnout and char removal zone, so that the outlet of the feeding pipe is close to the char removal port. The feeding auger (2) is used to transport biomass raw materials. The feeding pipe is equipped with spiral blades. When working, the spiral blades agitate, and the material can be turned over, fed and carbonized in the feeding pipe. Ignition device, used to ignite the combustible pyrolysis gas generated by carbonization in the carbonization furnace (1); The first blower (3) has its outlet split into a first ventilation duct (3a) and a second ventilation duct (3b). The first ventilation duct (3a) is connected to the main carbonization self-ignition zone and is used to provide the main combustion air. The second ventilation duct (3b) is connected to the right end of the furnace and is directly opposite the outlet of the feeding pipe. It is used to force-cool the discharged charcoal. The second blower (4) is connected to the burnout and char removal zone through the third ventilation duct (4a) to supply secondary air to ensure the complete combustion of combustible gas; As carbonization proceeds, the generated charcoal can be discharged through the charcoal discharge port; The generated combustible pyrolysis gas can spontaneously combust within the furnace, ultimately achieving system self-circulation.

2. The internal combustion carbonization system based on a spiral propulsion system for materials throughout the entire process, as described in claim 1, is characterized in that... The feeding pipe and spiral blades of the feeding auger (2) are made of high temperature resistant alloy, and their thermal conductivity is not less than 10W / (m·K); And / or, the propulsion surface of the helical blade and / or the inner wall of the feed tube are covered with a hard alloy wear-resistant layer formed by overlay welding; And / or, the surface of the feed pipe and / or the spiral blade is subjected to high-temperature aluminizing treatment; And / or, the feed auger (2) is provided with a cooling structure on the part outside the furnace to prevent the high temperature inside the furnace from being transmitted to its drive components; And / or, the edge of the spiral blade is provided with an elastic scraper strip for removing material adhering to the inner wall of the feeding pipe; And / or, the feed pipe is fixedly installed inside the furnace by a high-temperature resistant support structure, the support structure being configured to allow thermal expansion of the feed pipe.

3. The internal combustion carbonization system based on a spiral propulsion system for materials throughout the entire process, as described in claim 1, is characterized in that... The first ventilation duct (3a), the second ventilation duct (3b) and the third ventilation duct (4a) are all equipped with regulating valves. The regulating valves are used to adjust the air supply of the corresponding ducts so as to achieve precise matching of air volume for carbonization reaction and pyrolysis gas combustion. The carbonization system also includes: A first temperature sensor is used to monitor the temperature of the main carbonization and spontaneous combustion zone; The second temperature sensor is used to monitor the temperature of the carbon discharge port; A flue gas analyzer is used to monitor the composition of the flue gas discharged from the carbonization furnace (1); The control unit is electrically connected to the first temperature sensor, the second temperature sensor, and the flue gas analyzer, and signal-connected to the actuator of the regulating valve. The control unit is configured to execute the following control logic: The air supply of the first ventilation duct (3a) is adjusted in a closed loop according to the monitoring data of the first temperature sensor so that the temperature of the main carbonization and spontaneous combustion zone is stabilized within a preset range. The air supply of the second ventilation duct (3b) is adjusted in a closed loop according to the monitoring data of the second temperature sensor in order to control the carbon discharge temperature within a preset safe range. The air supply of the third ventilation duct (4a) is adjusted in a closed loop according to the monitoring data of the flue gas analyzer to ensure that the combustible components in the burnout and carbon removal zone are completely burned and the discharged flue gas meets the clean emission standards.

4. The internal combustion carbonization system based on a spiral propulsion system for materials throughout the entire process, as described in claim 1, is characterized in that... The outer wall of the feeding pipe is provided with a heat-conducting structure so as to better utilize the high temperature in the furnace to achieve carbonization of biomass raw materials; The heat-conducting structure is a fin provided on the outer tube wall. The fin is one or more combinations of radial fins, axial fins or spiral fins. The fin can enhance convection and radiation heat transfer by increasing the contact area. And / or, the heat-conducting structure ensures that the total effective heat exchange area of ​​the feed pipe is not less than 1.8 times its basic outer surface area; And / or, the heat-conducting structure includes one or more heat pipes embedded in the wall of the feed pipe, wherein the evaporation section of the heat pipe is disposed adjacent to the outer wall of the feed pipe and the condensation section is disposed adjacent to the inner wall of the feed pipe. And / or, the heat-conducting structure is achieved by roughening the outer wall of the feed tube or applying a high thermal conductivity coating.

5. The internal combustion carbonization system based on a spiral propulsion system for materials throughout the entire process, as described in claim 1, is characterized in that... The carbon discharge port is equipped with: A star-shaped discharge valve (11) is used for continuous discharge of charcoal; A cooling conveyor (12) is located downstream of the star-shaped discharge valve (11) and is used to receive, convey and cool charcoal. The cooling conveyor (12) is a jacketed screw conveyor, and the jacket of the cooling conveyor (12) is connected to the cooling medium circulation mechanism.

6. The internal combustion carbonization system based on a spiral propulsion system for materials throughout the entire process, as described in claim 5, is characterized in that... The drive shaft of the star-shaped unloading valve (11) is supported at both ends on an external cooling bearing seat. The external cooling bearing seat includes a bearing housing with a bearing inside and a cooling jacket. The cooling jacket is formed inside the bearing housing or wrapped around the bearing housing. The cooling jacket is connected to a cooling medium circulation mechanism. And / or, an anti-clogging device is provided between the carbonization furnace (1) and the star-shaped unloading valve (11), the anti-clogging device being an arch breaker or a vibrator; And / or, the star-shaped discharge valve (11) is equipped with a third temperature sensor, which is used to monitor the bearing temperature of the star-shaped discharge valve (11). The third temperature sensor is connected to the control system signal and is configured to perform the following operations: when the temperature value detected by the third temperature sensor exceeds a first preset threshold, an alarm signal is issued; when the temperature value detected by the third temperature sensor exceeds a second preset threshold higher than the first preset threshold, the star-shaped discharge valve (11) is controlled to stop.

7. The internal combustion carbonization system based on a spiral propulsion system for materials throughout the entire process, as described in claim 5, is characterized in that... The cooling conveyor (12) includes a multi-stage series discharge auger, which is used to cool and convey the discharged charcoal in stages. The first-stage discharge auger is connected to the charcoal discharge port and is used to receive the discharged charcoal. The subsequent multi-stage discharge augers can sequentially transport, cool and homogenize the charcoal. The final stage discharge auger is connected to multiple bulk bags (13), enabling simultaneous multi-channel collection and packaging of charcoal.

8. The internal combustion carbonization system based on a spiral propulsion system for materials throughout the entire process, as described in claim 7, is characterized in that... The screw speed of each stage of the discharge auger is independently adjustable, and decreases sequentially from the first stage to the last stage; And / or, the cooling conveyor (12) includes four stages of discharge augers, corresponding to the four process stages of high-temperature discharge, preliminary cooling, deep cooling and buffer collection, respectively.

9. The internal combustion carbonization system based on a spiral propulsion system for materials throughout the entire process, as described in claim 1, is characterized in that... It also includes an exhaust device (5), which is connected to the carbonization furnace (1) and is used to exhaust the flue gas after combustion; The exhaust device (5) is connected to the carbonization furnace (1) through a metal bellows expansion joint, which can compensate for the displacement between the two caused by thermal expansion. One end of the metal bellows expansion joint is fixedly connected to the carbonization furnace (1), and the other end is connected to the exhaust device (5) through a movable pipe. The movable pipe is supported by a sliding bracket so that it can slide as the metal bellows expansion joint expands and contracts.

10. The internal combustion carbonization system based on a spiral propulsion system for materials throughout the entire process, as described in claim 9, is characterized in that... The metal bellows expansion joint is an axial compound bellows, and its inner wall is provided with a high-temperature resistant and corrosion-resistant inner lining. And / or, the metal bellows expansion joint is covered with an insulation layer.

Images