Piston charging molten salt sub-heating pyrolysis system

Abstract

The present application relates to a kind of pyrolysis system of piston loading molten salt segmented heating, it includes electric control unit, loading equipment, pyrolysis equipment and unloading equipment;Three equipment are sequentially connected;Pyrolysis gas collection equipment is further provided on the pyrolysis equipment, and control unit is to three equipment;The pyrolysis equipment is by molten salt furnace, molten salt pump, pyrolysis container and heat exchanger arranged on the wall of pyrolysis container composition;The molten salt furnace is heated by molten salt, and is pumped into the heat exchanger on the pyrolysis container by molten salt pump, heat exchanger is regularly arranged on the container wall, and the container is heated, and the inside of container is equipped with chain plate, and organic material is loaded on chain plate;Under the transmission of chain plate, pass through the container cavity of different temperature, to complete pyrolysis;Organic material after pyrolysis is completed is transferred by unloading equipment;Electric control unit overall control and coordination above-mentioned equipment device.Solve the problem of vacuum degree in container when pyrolyzing, simultaneously solve efficiency and fouling problem.

Description

Technical Field

[0001] This invention relates to the pyrolysis of organic waste, specifically to a pyrolysis system with piston feeding and segmented heating of molten salt. Background Technology

[0002] In existing technologies, organic waste needs to undergo pyrolysis to remove harmful substances, thus turning it into organic fertilizer for reuse. Pyrolysis must be carried out in a pyrolysis furnace. Currently, there are two types of pyrolysis furnaces on the market: one is a fixed, sealed furnace, where the organic matter is placed inside and heated to a high temperature until it reaches a certain temperature for a specific time. Then, the lid is opened, and the pyrolyzed organic matter is removed. This method is unsuitable for large-scale processing plants due to uneven heating and low efficiency. The other type is a rotary kiln pyrolysis furnace, where the organic matter is heated in a container on a furnace. The container rotates continuously on the furnace, causing the organic matter inside to tumble constantly. The continuous change in heating position also makes the internal heating relatively uniform. However, this type of furnace still has a fatal drawback: scaling on the inner wall of the container. This is because when organic matter is heated to high temperatures, in addition to carbonization and decomposition, the instantaneous temperature change causes the organic matter to release oil. Over time, this oil will form scale on the wall, thus affecting the heating. If this continues for too long, the container will shrink, or even cause an explosion.

[0003] Another factor affecting the effectiveness of a pyrolysis furnace is whether the carbonization and pyrolysis environment is under vacuum. In existing technologies, since pyrolysis generally doesn't involve organic matter, the vacuum requirement is not high. However, this is not the case for organic matter pyrolysis, as the process involves oxygenation and produces nitrogen, which is very dangerous. Observations of equipment currently on the market show that the low vacuum level is mainly due to issues during loading. Currently, most organic material loading is done using a auger-assisted device; this device cannot create a complete seal, and a seal is difficult to achieve while it is constantly rotating. Furthermore, during material pushing, it cannot guarantee that the container will be 100% full, leaving space for the auger to agitate, thus resulting in a lower internal vacuum. Of course, a vacuum pump can be added to the pyrolysis equipment to ensure a vacuum, but this seems quite expensive. Summary of the Invention

[0004] To overcome the above-mentioned technical problems, this invention proposes a pyrolysis system with piston-feed molten salt and segmented heating; it aims to solve the problem of vacuum degree in the container during pyrolysis, while also solving the problems of efficiency and scaling.

[0005] This invention provides a piston-fed molten salt segmented heating pyrolysis system, comprising a loading device, a pyrolysis device, and a unloading device; the three devices are sequentially connected; a pyrolysis gas collection device is also provided on the pyrolysis device, and an electrical control unit is connected to the three devices; the pyrolysis device consists of a molten salt furnace, a molten salt pump, a pyrolysis container, and heat exchangers arranged on the wall of the pyrolysis container; the molten salt furnace heats the molten salt, which is pumped into the heat exchangers on the pyrolysis container by the molten salt pump. The heat exchangers are regularly arranged on the container wall to heat the container. The container is equipped with a chain plate, on which organic materials are loaded; under the conveying of the chain plate, the materials pass through container cavities at different temperatures, thereby completing the pyrolysis; the pyrolyzed organic materials are transferred through the unloading device; the electrical control unit controls and coordinates the above-mentioned equipment.

[0006] Molten salt, as a heating medium, has not been used in pyrolysis furnaces until now. However, since this invention involves pyrolyzing organic waste, the pyrolysis temperature of which happens to match that of molten salt. For this reason, this invention uses this medium for heat conduction. In fact, in existing technologies, it is generally believed that using a medium for heat conduction leads to energy waste and is therefore generally avoided, with direct heating being the preferred method. However, this is a misunderstanding in the industry. While heat conduction does involve energy consumption, the medium is also an energy-storing fluid. Calculations show that direct combustion heating or electromagnetic heating (referring to direct heating of the container) consumes far more energy than heat conduction due to heat absorption and conductivity. Another point is that molten salt heating has the advantage of becoming liquid above 200 degrees Celsius, reaching a maximum of 600 degrees Celsius. The pyrolysis temperature of organic waste falls precisely within this temperature range. Furthermore, this heating method allows for temperature control; by controlling the flow rate, the temperature can be accurately controlled. Accurate temperature control solves problems such as scaling and pyrolysis rate issues, thereby increasing the pyrolysis effect.

[0007] In this solution, to ensure the vacuum level inside the container, a piston-type loading device is used. Unlike existing technologies, this piston-type loading device, after pushing in the material, simultaneously extracts some air from the container when the piston is pulled back. This process is repeated multiple times, thereby increasing the vacuum level inside the container. This push-and-pull action itself has a vacuum-generating function, and this invention integrates it well with the container, achieving two goals at once. Its specific structure includes a feeding hopper, a feeding valve, a reciprocating piston pusher, a reciprocating space, a feeding baffle, an oxygen-free chamber, and a discharging baffle. The feeding valve is located at the outlet of the feeding hopper. The reciprocating piston pusher pushes the material along the reciprocating space through the feeding baffle into the oxygen-free chamber. After the reciprocating piston pusher pulls back and exits the oxygen-free chamber, the feeding valve closes. The feeding valve is equipped with a one-way vent valve, which, with the piston's backward pull, extracts air from the oxygen-free chamber. Stop pumping after reaching the feed valve. If the vacuum level in the oxygen-free chamber is deemed insufficient, the reciprocating piston pusher will pump back and forth again to vent the air out of the oxygen-free chamber.

[0008] This allows a single device to both push and vacuum, achieving two functions in one unit.

[0009] Of course, both the feed plate and the discharge plate can be made into sealed plates, and a vacuum device can be installed above the oxygen-free chamber to eliminate the reciprocating space.

[0010] To further improve the above technical solution, a rotary pyrolysis furnace is installed after the pyrolysis equipment; the inlet of the rotary pyrolysis furnace is directly connected to the pyrolysis equipment via a conveying mechanism.

[0011] Due to the temperature limitations of molten salt pyrolysis furnaces—meaning the maximum temperature of molten salt is only 600 degrees Celsius, and higher temperatures are virtually impossible—this molten salt furnace is added to the existing rotary furnace to further react materials that were not reacted or not fully reacted in the original furnace, allowing the reaction to take place within the existing equipment. This setup also completely solves the problem of scaling in the rotary furnace.

[0012] Further improvements to the above technical solution are made to the pyrolysis vessel, which is divided into several sections, including at least an initial temperature section, an intermediate temperature section, and a high temperature section, wherein the initial temperature section has a temperature higher than 200 degrees, the intermediate temperature section reaches 400 degrees, and the high temperature section reaches 600 degrees; a transition space is provided between the three temperature sections.

[0013] The function of pyrolysis equipment is to decompose the pyrolysis products into organic fertilizer at high temperatures, and to crack inorganic and harmful substances to obtain harmless hydrogen and water. During pyrolysis, scaling often occurs, primarily due to the rapid temperature rise, especially when the temperature suddenly jumps from a low-temperature zone to a high-temperature zone (e.g., from 200°C to 600°C). At this point, the liquid components cannot undergo physical changes through evaporation; instead, they are directly subjected to extremely high temperatures, leading to severe scaling. In existing technologies, direct heating using a rotary furnace often results in a linear temperature increase without a gradual heating process. This often leads to incomplete reactions, scaling, impure gas reactions, or the generation of harmful gases during the process. This solution differs by setting different temperature zones, allowing the material to move from a low-temperature zone through a medium-temperature zone to a high-temperature zone, with sufficient reaction time in each zone. In the low-temperature zone, the main process is the evaporation of liquid gases; in the medium-temperature zone, the main process is the solidification of the material; and in the high-temperature zone, the internal chain reorganization and reaction changes occur, removing harmful substances.

[0014] Further improvements to the above technical solution include the installation of a chain conveyor mechanism within the molten salt furnace. The material is placed on the chain, and a shovel plate is installed at the end of the chain. The purpose of the shovel plate is to maintain the chain during long-term use. Due to the improvements in the molten salt furnace, scale will no longer form on the center or other parts of the chain in this solution. However, due to differences in the moisture content of the material, variations in the amount of material, and slight temperature changes, scale may still form on the sidewalls of the chain, or due to incomplete material disposal. Therefore, after long-term use, the chain can be cleaned periodically using the shovel plate. The shovel plate can both remove residual material from the pallet and its position can be adjusted to clean the scale on the sidewalls.

[0015] This invention is a further optimization based on previous system designs. Through a series of electronic controls, the various parts work in coordination. The specific workflow is as follows: material is pushed by a piston-pushing device within a sealed space. The piston's pushing and pulling further removes air from the device, allowing the material to be fed into the pyrolysis furnace under oxygen-deficient conditions. Within the furnace, the material passes through the initial, intermediate, and high-temperature zones. Upon reaching a certain temperature, the carbon and hydrogen bonds of the large organic molecules in the material break, recombine, and form smaller, combustible gases. Petroleum gum, some light oil, and carbon are separated by a separation system. The oil is separated, and the water is condensed and recycled. Gases such as methyl, ethyl, propylene, dioxins, and benzoyl peroxide are treated and returned to the storage tank. Because the treatment process is segmented, the emitted gases do not contain toxic gases such as dioxins. The emitted organic matter can be directly converted into fertilizer. Attached Figure Description

[0016] Figure 1This is an overall system diagram of the present invention.

[0017] Figure 2 This is a partial structural diagram of the pyrolysis furnace.

[0018] Figure 3 This is a diagram showing the structural fit between the scraper and the chain plate.

[0019] Figure 4 This is a schematic diagram of the rotary furnace. Detailed Implementation

[0020] As shown in the figure, a piston-fed molten salt pyrolysis system with segmented heating comprises an electronic control unit, an external feeding device, a sealed piston feeding system, a segmented heating pyrolysis system, a condensation device, a condensate recovery tank, a gas separation device, and a gas recovery device. The electronic control unit controls and coordinates the operation of the aforementioned equipment. The external feeding device delivers pre-treated material to the sealed piston feeding system, which pushes the material to the segmented heating pyrolysis system under relative vacuum conditions. The segmented heating pyrolysis system heats the material from low to high temperatures. At the lowest temperature, the moisture contained in the material is condensed by the condensation system, and the recovered condensate is collected and stored in the condensate recovery tank. The pyrolyzed gas then enters the gas separation device to separate the different gases.

[0021] The segmented heating pyrolysis system is heated by pyrolysis equipment, which consists of a molten salt furnace, a molten salt pump, a pyrolysis container, and heat exchangers arranged on the walls of the pyrolysis container. The molten salt furnace heats the molten salt, which is pumped into the heat exchangers on the pyrolysis container by the molten salt pump. The heat exchangers are arranged regularly on the container walls to heat the container. The pyrolysis container includes at least an initial temperature section, an intermediate temperature section, and a high temperature section, where the initial temperature section is higher than 200 degrees Celsius, the intermediate temperature section reaches 400 degrees Celsius, and the high temperature section reaches 600 degrees Celsius. A transition space is provided between the three temperature sections.

[0022] The segmented heating pyrolysis system's pyrolysis vessel is divided into several layers from top to bottom, each with a different temperature ranging from 200 to 600 degrees Celsius, and the layers are sealed. The sealed spaces are interconnected. Different recovery mechanisms are installed between each layer; for example, water vapor is collected between the 200-degree layers, and pyrolysis gas is collected between the 600-degree layers. To ensure a more thorough reaction of harmful substances in the material, a rotary pyrolysis furnace is added after the pyrolysis reactor; the inlet of the rotary pyrolysis furnace is directly connected to the molten salt pyrolysis furnace via a conveying mechanism.

[0023] The pretreated material is continuously fed into the feeding system and, via a piston-type charging device, is fed into the pyrolysis reactor under oxygen-deficient conditions. The piston-type charging device consists of a feed hopper 1, a feed valve 2, a reciprocating piston pusher 3, a feed space, a feed baffle 4, a discharge baffle 5, an oxygen-free chamber 6, and a transfer hopper. The feed hopper is located above the feed valve, which is located between the reciprocating piston pusher and the feed baffle. When the feed valve is opened, the material is placed after the reciprocating piston pusher. The space between the feed baffle and the discharge baffle is a sealed space. A reciprocating piston pusher pushes material into the oxygen-free chamber. After extraction, the feed baffle immediately closes, and the piston continues to pull backward. Because the feed baffle is equipped with a one-way valve, air can only exit and not enter. Therefore, during the extraction process, the air in the oxygen-free chamber is evacuated. Furthermore, if the vacuum level in the oxygen-free chamber is insufficient, the reciprocating piston pusher can move back and forth within the reciprocating space to achieve a vacuum. Alternatively, a vacuum device 7 can be added above the oxygen-free chamber to achieve a high vacuum. The evacuated material is then sent to the pyrolysis vessel 9 via a transfer hopper. The pyrolysis vessel is divided into at least three layers (upper, middle, and lower), consisting of at least three temperature steps, from bottom to top (details omitted). The vessel uses a chain conveyor for transport; the end of the chain is the inlet of the next layer, and the next layer reverses direction, with its outlet connected to the next layer. This cycle continues, and the number of layers can be adjusted according to actual needs. Because pipeline heating is used, the number of layers is not significantly increased in cost. From a conversion rate perspective, it is far superior to direct heating. To prevent scaling from forming on the edges or bottom of the chain plate 11 due to larger temperature variations in cases with fewer container layers, a scraper plate 12 is installed at the end of the chain plate. The chain plate is designed to rotate via a chain and gears, with the material-carrying tray fixed in the middle of the chain. The tray is positioned between the chain sections, while the scraper plate is fixed at the end of the chain, either at the bottom center or on either side of the tray. By contacting the bottom of the tray, the scraper plate scoops up the material, or by contacting the side walls of the tray, it removes scale. The purpose of the scraper plate is to maintain the chain plate 11 after long-term use. Due to improvements in the molten salt furnace, scaling no longer forms in the center or other parts of the chain plate. However, variations in material moisture content, quantity, and slight temperature changes can still cause scaling on the side walls of the chain plate. Therefore, after long-term use, the chain plate can be cleaned periodically using the scraper plate.

[0024] The specific workflow described above is as follows: Material is pushed through a piston-pushing device within a sealed space. The piston's pushing and pulling further removes air from the device, allowing the material to be fed into the pyrolysis furnace under oxygen-deficient conditions. Within the furnace, the material passes through the initial temperature zone, intermediate temperature zone, and high temperature zone. Upon reaching a certain temperature, the carbon and hydrogen bonds of the large organic molecules in the material break, recombine, and form small-molecule combustible gases. Petroleum gum, some light oil, and carbon are separated by a separation system. The oil is separated, and the water is condensed and recycled. Gases such as methyl methacrylate (MDMA), ethyl methacrylate (EM), dioxins, and benzoyl peroxide (DPO4) are treated and returned to the storage tank. Because the treatment process is segmented, the emitted gases do not contain toxic gases such as dioxins. The emitted organic matter can be directly converted into fertilizer. Detailed Implementation

[0026] Building upon the aforementioned scheme, to ensure a more complete material reaction, and considering the temperature limitations of the molten salt pyrolysis furnace—that is, the maximum temperature of molten salt is only 600 degrees Celsius, and higher temperatures are virtually impossible—a molten salt furnace is added to the existing rotary furnace to further react any unreacted or incompletely reacted materials within the original equipment. This setup also completely resolves the scaling problem in the rotary furnace.

[0027] The material from the previous method enters the rotary furnace through inlet 14 and is fed into the rotary furnace by the feeding device 16. The stirring device 15 inside the furnace, driven by the motor 13, continuously stirs the material, ensuring a more thorough reaction. Since the material being processed in the rotary furnace is already at around 600 degrees Celsius, scaling will not occur inside the furnace. This solves both the problem of complete reaction and the problem of scaling in the rotary furnace.

Claims

1. A piston-fed molten salt staged heating pyrolysis system, comprising an electrical control unit, a loading device, a pyrolysis device, and a unloading device; the three devices are connected in sequence; a pyrolysis gas collection device is also provided on the pyrolysis device, and the electrical control unit is connected to the three devices; characterized in that: The cracking device is composed of a molten salt furnace, a molten salt pump, a cracking container and heat exchangers arranged on the wall of the cracking container; the molten salt furnace is heated by molten salt, which is pumped into the heat exchangers arranged on the wall of the cracking container; the heat exchangers are regularly arranged on the wall of the container to heat the container; the container is internally provided with a chain plate on which the organic material is arranged; under the transmission of the chain plate, the organic material passes through cavities of the container with different temperatures to complete the cracking; the cracked organic material is transported by a discharging device; and an electric control unit controls and coordinates the above devices as a whole. The loading device adopts a piston type loading device, which comprises a feeding bin, a feeding valve, a reciprocating piston feeder, a reciprocating space, a feeding partition, an oxygen-free bin and a discharging partition; the feeding valve is located at the outlet of the feeding bin; the reciprocating piston feeder pushes the feed into the feeding partition through the reciprocating space and then into the oxygen-free bin; the reciprocating piston feeder is pulled back; the air in the oxygen-free bin is discharged after the reciprocating piston feeder is pulled back; the feeding valve is closed; a one-way air outlet valve is arranged on the feeding valve; and the air in the oxygen-free bin is discharged along with the pulling back of the piston.

2. A segmented heating pyrolysis system with piston-fed molten salt according to claim 1, characterized in that: A rotary cracking furnace is arranged after the cracking device; the inlet of the rotary cracking furnace is directly connected with the cracking device through a conveying mechanism.

3. A segmented heating pyrolysis system with piston-fed molten salt according to claim 1, characterized in that: The cracking container is divided into several sections, at least including a primary temperature section, a medium temperature section and a high temperature section; the temperature of the primary temperature section is higher than 200 degrees, the temperature of the medium temperature section reaches 400 degrees and the temperature of the high temperature section reaches 600 degrees; and transition spaces are arranged between the three temperature sections.

4. The pyrolysis system for piston-fed molten salt staged heating according to claim 1, characterized in that: A chain plate conveying mechanism is arranged in the molten salt furnace; and the material is arranged on the chain plate; and a shovel plate is arranged at the end of the chain plate.

Images