Pyrolysis gas treatment system and method

Abstract

This invention provides a pyrolysis gas treatment system and method. The system includes a pyrolysis furnace, a dust removal device, and a hot air furnace. The dust removal device includes a cyclone dust collector for removing large-particle-size dust (10 μm or larger) from the pyrolysis gas. The dust removal device also includes a terminal dust collector disposed between the cyclone dust collector and the hot air furnace for removing remaining small-particle-size dust from the pyrolysis gas. The terminal dust collector includes: a terminal cylinder having a terminal inlet for pre-treated pyrolysis gas to enter, a terminal dust outlet for small-particle-size dust to flow out, and a terminal outlet for pyrolysis gas to flow out; a cover sealing the terminal outlet and connected to the hot air furnace via a pipe; a sealing plate held between the terminal cylinder and the cover; a metal microporous membrane filter bag detachably suspended inside the terminal cylinder; and a dust baffle plate disposed on the inner wall of the terminal cylinder, located between the terminal inlet and the metal microporous membrane filter bag. This invention ensures efficient separation and treatment of small-particle-size dust (less than 10 μm) from the pyrolysis gas.

Description

Technical Field

[0001] This invention relates to the field of waste treatment technology, specifically to a pyrolysis gas treatment system and method. Background Technology

[0002] There are many ways to treat solid waste, such as landfill, composting, incineration, pyrolysis, and gasification. The choice of treatment method depends on various factors, such as the source and type of solid waste, the equipment and location for waste treatment, etc. Previously, solid waste was often stored in open landfills and then incinerated in the open. Hazardous waste from industry was often disposed of together with municipal waste in open landfills or landfills. Landfilling causes various environmental problems, including soil and groundwater pollution, emissions of toxic gases and greenhouse gases, and an increase in the number of flies and mosquitoes that cause various diseases. With the rapid pace of urbanization in my country, a large amount of solid waste has been generated in this process, causing serious environmental impacts.

[0003] Pyrolysis, a current method for treating solid waste, is a process of thermally decomposing organic matter in an anaerobic environment to obtain energy products such as pyrolysis oil, biochar, and pyrolysis gas. The gaseous products of pyrolysis contain combustible components such as hydrogen (H2), carbon monoxide (CO), and methane (CH4). Discarding these low-calorific-value gases not only results in a significant loss of energy, but CO gas also pollutes the Earth's environment. Therefore, the energy utilization of pyrolysis gas from organic solid waste is of great importance.

[0004] Chinese patent CN108913173A discloses a method and system for recovering and utilizing pyrolysis gas and oil. Waste is fed into a pyrolysis furnace via a conveyor, where pyrolysis takes place. Part of the pyrolysis gas is first treated for oil recovery and then returned to the combustion chamber, while the remainder is directly fed into the combustion chamber. By adjusting the ratio of the pyrolysis gas fed into the oil removal treatment and the gas directly fed into the combustion chamber, the temperature of the combustion chamber is controlled within a preset range. This system is particularly suitable for pyrolysis treatment of waste containing a large amount of tar in the pyrolysis gas. The heat source required for pyrolysis is directly supplied by burning the pyrolysis gas. Excess tar in the pyrolysis gas is recovered through two-stage oil condensation, maximizing the recovery and reuse of oil from the pyrolysis gas, increasing the byproducts of pyrolysis treatment, and resulting in significant economic benefits.

[0005] However, high-temperature pyrolysis gas has a complex composition, containing room-temperature non-condensable gases (CH4, H2, and CO, etc.), tar vapor, water vapor, and dust. The aforementioned technical solutions achieve full recovery and utilization of tar. However, in terms of dust removal, due to the small particle size and wide distribution of dust in the pyrolysis gas, the commonly used cyclone dust collectors in existing technologies are highly efficient at removing large particles (above 10 μm) from the pyrolysis gas. However, smaller dust particles are difficult to separate efficiently using cyclone dust collectors. Summary of the Invention

[0006] In view of this, the present invention provides a pyrolysis gas treatment system and method to solve the technical problem that it is difficult to efficiently separate small dust particles with a particle size of less than 10 μm in pyrolysis gas in the prior art.

[0007] To solve the above problems, the first aspect of the present invention provides a pyrolysis gas treatment system, which adopts the following technical solution:

[0008] A pyrolysis gas treatment system includes a pyrolysis furnace, a dust removal device, and a hot air furnace. The pyrolysis gas generated from the pyrolysis of domestic waste in the pyrolysis furnace is treated by the dust removal device and then introduced into the hot air furnace for combustion. The hot gas generated by combustion is introduced into the pyrolysis furnace to provide the temperature required for the pyrolysis reaction.

[0009] The dust removal device includes a cyclone dust collector, which is used to pre-dust remover of pyrolysis gas to remove large-particle dust with a diameter of 10 μm or more from the pyrolysis gas. The cyclone dust collector has a pre-inlet for pyrolysis gas to enter, a pre-dust outlet for large-particle dust to flow out, and a pre-outlet for pyrolysis gas to flow out.

[0010] The dust removal device further includes a terminal dust collector disposed between the cyclone dust collector and the hot air furnace. The terminal dust collector is used to perform final dust removal treatment on the pyrolysis gas after pre-dust removal to remove residual small-particle dust in the pyrolysis gas. The terminal dust collector includes:

[0011] The terminal cylinder has a terminal inlet for the pyrolysis gas after pre-dust removal treatment to enter, a terminal dust outlet for the small-diameter dust to flow out, and a terminal outlet for the pyrolysis gas to flow out. The terminal dust outlet and the terminal outlet are located at the bottom and top of the terminal cylinder, respectively, and the terminal inlet is located on the side wall of the terminal cylinder.

[0012] A cap, which is detachably mounted on the top of the terminal cylinder and is used to block the terminal outlet, is connected to the hot air furnace via a pipe;

[0013] The sealing plate is detachably disposed between the terminal cylinder and the sealing cover, and is clamped and fixed by the terminal cylinder and the sealing cover.

[0014] A metal microporous membrane filter bag is movable through a sealing plate and its top is detachably connected to the sealing plate, so that the metal microporous membrane filter bag is suspended in the terminal cylinder along the axial direction of the terminal cylinder;

[0015] The dust baffle is installed on the inner wall of the terminal cylinder and located between the terminal inlet and the metal microporous membrane filter bag. The dust baffle is arranged along the axial direction of the terminal cylinder. The upper parts of both ends of the dust baffle are connected to the inner wall of the terminal cylinder through connecting plates. The terminal inlet corresponds to the upper part of the dust baffle. An air outlet slot is opened through the connecting plate, and several air outlet holes are evenly opened through the lower part of the dust baffle.

[0016] The beneficial effects are as follows: This invention achieves the purpose of clamping and fixing the sealing plate by installing and connecting the cover and the terminal cylinder, thereby achieving the purpose of fixing the metal microporous membrane filter bag. It is convenient to disassemble and assemble, and facilitates the regular cleaning and replacement of the metal microporous membrane filter bag. This invention is equipped with a dust baffle plate. The pyrolysis gas enters the terminal cylinder from the terminal inlet. It first directly hits the upper part of the dust baffle plate and disperses. Part of it passes through the air outlet slot and splits into two streams that flow around the metal microporous membrane filter bag. Part of it passes through the air outlet and flows in the direction of impacting the metal microporous membrane filter bag. Part of it flows straight down until it passes the bottom of the dust baffle plate, and then flows upward to wrap around the metal microporous membrane filter bag. This makes the pyrolysis gas evenly dispersed before being filtered by the metal microporous membrane filter bag. The metal microporous membrane filter bag can filter out dust particles with a diameter of less than 10μm in the pyrolysis gas, while improving the filtration efficiency and effect.

[0017] As a further improvement, the middle part of the dust baffle is bent towards the terminal cylinder to form an arc-shaped groove that matches the outer wall of the metal microporous membrane filter bag. This allows the pyrolysis gas passing through the air outlet to impact the outer wall of the metal microporous membrane filter bag radially, while reducing the volume of space formed between the dust baffle and the terminal cylinder.

[0018] The beneficial effects are as follows: the arc-shaped groove design allows the curvature of the dust baffle to match the outer wall of the metal microporous membrane filter bag, ensuring that the portion of pyrolysis gas flowing through the air outlet impacts the metal microporous membrane filter bag radially, thereby achieving better uniform dispersion and filtration effect; at the same time, the presence of the arc-shaped groove reduces the space volume formed between the dust baffle and the terminal cylinder, which can accelerate the flow rate of pyrolysis gas in this space, thereby improving filtration efficiency.

[0019] As a further improvement, the two ends of the dust baffle are bent toward the direction of the terminal cylinder to form an outward flange, and the connecting plate is connected to the upper part of the outward flange.

[0020] The beneficial effects are as follows: The presence of the outward-turned edge creates a groove between the dust baffle and the outward-turned edge, achieving the effects of air gathering and air guiding. This ensures that the groove is always filled with flowing pyrolysis gas. This ensures that some pyrolysis gas overflows from the upper part of the outward-turned edge and flows through the air outlet slot and around the metal microporous membrane filter bag; some pyrolysis gas overflows from the lower part of the outward-turned edge and flows around the metal microporous membrane filter bag; some pyrolysis gas flows through the air outlet hole located at the lower part of the dust baffle and flows in the direction of impacting the metal microporous membrane filter bag; and some pyrolysis gas flows through the groove until it crosses the bottom of the dust baffle and disperses upward in the direction of wrapping the metal microporous membrane filter bag. This helps to further evenly disperse the pyrolysis gas, thereby achieving a more efficient and better filtration effect.

[0021] As a further improvement, a mounting hole is formed through the center of the sealing plate, and a fitting ring plate is provided around the mounting hole on the top of the sealing plate. A circular slot is formed on the fitting ring plate, and a limiting ring is provided on the top of the metal microporous membrane filter bag. The limiting ring is detachably set in the circular slot.

[0022] The beneficial effects are as follows: by inserting / pulling the limiting ring into the circular slot, the metal microporous membrane filter bag can be quickly disassembled and assembled, and then cleaned or replaced. The disassembly and assembly are convenient, and regular cleaning or replacement is easy, ensuring that the filtration effect can be maintained continuously.

[0023] As a further improvement, a support frame is detachably suspended on the mounting ring plate. The support frame is located inside the metal microporous membrane filter bag to prevent the metal microporous membrane filter bag from deforming due to the impact of airflow.

[0024] The beneficial effects are as follows: by setting up a support frame, the shape of the metal microporous membrane filter bag is supported (maintained), preventing the metal microporous membrane filter bag from easily deforming due to the impact of pyrolysis gas flow, and ensuring that the filtration performance of the metal microporous membrane filter bag is maintained well.

[0025] As a further improvement, the top of the mounting ring plate is evenly provided with several slots along the circumferential direction, the slots are arranged radially along the mounting ring plate, and the top of the support frame is evenly provided with several outward-folding rods, which are inserted into the slots.

[0026] The beneficial effects are as follows: by inserting / removing the outward-folding rod into the slot, the support frame can be quickly assembled and disassembled, ensuring convenient assembly and disassembly; at the same time, the outward-folding rod presses against the top of the limiting ring, effectively preventing the limiting ring from coming out of the circular slot, thus improving the installation firmness and reliability of the metal microporous membrane filter bag.

[0027] As a further improvement, the pre-inlet is connected to the pyrolysis gas outlet of the pyrolysis furnace via a pre-inlet pipe. The pre-inlet pipe includes an air inlet pipe connected to the pre-inlet, an air inlet straight pipe section connected to the other end of the air inlet pipe, a small round pipe section connected to the pyrolysis gas outlet of the pyrolysis furnace, a connecting cone pipe section connected to the other end of the small round pipe section, and a large round pipe section connected to the other end of the connecting cone pipe section. The diameters of the air inlet straight pipe section and the large round pipe section are equal. The air inlet straight pipe section and the large round pipe section are externally detachable sleeves and fastened with pipe clamps to connect the air inlet straight pipe section and the large round pipe section. The diameter of the air inlet pipe increases from the end connected to the air inlet straight pipe section to the end connected to the pre-inlet, and the diameter of the connecting cone pipe section increases from the end connected to the small round pipe section to the end connected to the large round pipe section.

[0028] The beneficial effects are as follows: First, the connection between the straight inlet pipe section and the large circular pipe section is achieved by fitting sleeves and securing them with pipe clamps, ensuring convenient disassembly and assembly of the connecting pipes between the pyrolysis furnace and the cyclone dust collector, facilitating maintenance. Second, the progressively changing diameter of the connecting conical pipe section and the inlet pipe ensures that the flow velocity of the pyrolysis gas gradually decreases as it flows from the pyrolysis furnace to the cyclone dust collector, preventing the pyrolysis gas from entering the cyclone dust collector at excessively high speeds and affecting the dust removal effect. Finally, when assembling and using the pyrolysis furnace and the cyclone dust collector, there is no need to consider whether the pre-inlet diameter matches the pyrolysis gas outlet diameter of the pyrolysis furnace; only the appropriately sized large circular pipe section, connecting conical pipe section, and small circular pipe section need to be customized, improving the compatibility of use.

[0029] The second aspect of this invention provides a method for treating pyrolysis gas, which adopts the following technical solution:

[0030] A method for treating pyrolysis gas, using the aforementioned pyrolysis gas treatment system, includes the following steps:

[0031] After being crushed and dried, the domestic waste is fed into a pyrolysis furnace for pyrolysis treatment, generating pyrolysis gas. The gas flows into a cyclone dust collector through a pre-inlet for pre-dust removal. Large dust particles larger than 10μm flow out through the pre-dust outlet, and then the pyrolysis gas flows out through the pre-outlet.

[0032] Pyrolysis gas flows into the terminal cylinder through the terminal inlet and collides directly with the upper part of the dust baffle. After the collision, the pyrolysis gas flows in all directions. Part of it passes through the air outlet slot and splits into two streams that flow around the metal microporous membrane filter bag. Part of it passes through the air outlet and flows in the direction of impacting the metal microporous membrane filter bag. Part of it flows straight down until it passes the bottom of the dust baffle and then flows upward to wrap around the metal microporous membrane filter bag.

[0033] The remaining small dust particles smaller than 10μm in the pyrolysis gas are blocked by the metal microporous membrane filter bag and flow out through the terminal dust outlet. The pyrolysis gas that enters the metal microporous membrane filter bag finally flows out through the terminal outlet and into the hot air furnace for combustion. The heat generated by combustion is supplied to the pyrolysis furnace.

[0034] The above-described technical solution of the present invention has at least the following beneficial effects:

[0035] 1. This invention achieves the purpose of clamping and fixing the sealing plate by installing and connecting the cover and the terminal cylinder, thereby fixing the metal microporous membrane filter bag. It is easy to disassemble and assemble, and facilitates the regular cleaning and replacement of the metal microporous membrane filter bag. This invention is equipped with a dust baffle plate. The pyrolysis gas enters the terminal cylinder from the terminal inlet. It first directly hits the upper part of the dust baffle plate and disperses. Part of it passes through the air outlet slot and splits into two streams that flow around the metal microporous membrane filter bag. Part of it passes through the air outlet and flows in the direction of impacting the metal microporous membrane filter bag. Part of it flows straight down until it passes the bottom of the dust baffle plate, and then flows upward to wrap around the metal microporous membrane filter bag. This makes the pyrolysis gas evenly dispersed before being filtered by the metal microporous membrane filter bag. The metal microporous membrane filter bag can filter out dust particles with a diameter of less than 10μm in the pyrolysis gas, while improving the filtration efficiency and effect.

[0036] 2. The middle part of the dust baffle is bent towards the terminal cylinder to form an arc-shaped groove that matches the outer wall of the metal microporous membrane filter bag. This ensures that the portion of pyrolysis gas flowing through the air outlet impacts the metal microporous membrane filter bag radially, achieving better uniform dispersion and filtration effect. At the same time, the presence of the arc-shaped groove reduces the space volume formed between the dust baffle and the terminal cylinder, which can accelerate the flow rate of pyrolysis gas in this space, thereby improving filtration efficiency.

[0037] 3. The two ends of the dust baffle are bent towards the terminal cylinder to form outward flanges. The connecting plate is connected to the upper part of the outward flanges. The presence of the outward flanges creates a groove between the dust baffle and the outward flanges, achieving the effect of air gathering and flow guidance. This ensures that the groove is always filled with flowing pyrolysis gas. This ensures that some pyrolysis gas overflows from the upper part of the outward flanges and flows through the air outlet slot and around the metal microporous membrane filter bag; some pyrolysis gas overflows from the lower part of the outward flanges and flows around the metal microporous membrane filter bag; some pyrolysis gas flows through the air outlet at the lower part of the dust baffle and flows towards impacting the metal microporous membrane filter bag; and some pyrolysis gas flows through the groove until it crosses the bottom of the dust baffle and disperses upward towards the direction of wrapping the metal microporous membrane filter bag. This helps to further evenly disperse the pyrolysis gas, achieving a more efficient and better filtration effect.

[0038] 4. An installation hole is made through the center of the sealing plate. A fitting ring plate is set around the installation hole on the top of the sealing plate. A circular slot is made on the fitting ring plate. A limiting ring is set on the top of the metal microporous membrane filter bag. The limiting ring is detachably set in the circular slot. By inserting / pulling the limiting ring into the circular slot, the metal microporous membrane filter bag can be quickly disassembled and assembled, and then cleaned or replaced. The disassembly and assembly are convenient, and it is easy to clean or replace regularly to ensure that the filtration effect can be maintained continuously.

[0039] 5. The mounting ring plate has a detachable hanging support frame. The support frame is located inside the metal microporous membrane filter bag and supports (maintains) the shape of the metal microporous membrane filter bag, preventing the metal microporous membrane filter bag from being easily deformed by the impact of pyrolysis gas flow, and ensuring that the filtration performance of the metal microporous membrane filter bag is maintained.

[0040] 6. Several slots are evenly opened on the top of the ring plate along the circumferential direction. The slots are arranged radially along the ring plate. Several outward-folding rods are evenly arranged on the top of the support frame and are inserted into the slots. By inserting / removing the outward-folding rods into the slots, the support frame can be quickly assembled and disassembled, ensuring convenient assembly and disassembly. At the same time, the outward-folding rods press against the top of the limiting ring, effectively preventing the limiting ring from coming out of the circular slot, thus improving the installation firmness and reliability of the metal microporous membrane filter bag.

[0041] 7. The pre-inlet is connected to the pyrolysis gas outlet of the pyrolysis furnace via a pre-inlet pipe. The pre-inlet pipe includes an inlet pipe connected to the pre-inlet, an inlet straight pipe section connected to the other end of the inlet pipe, a small round pipe section connected to the pyrolysis gas outlet of the pyrolysis furnace, a connecting cone pipe section connected to the other end of the small round pipe section, and a large round pipe section connected to the other end of the connecting cone pipe section. The diameters of the inlet straight pipe section and the large round pipe section are equal. The inlet straight pipe section and the large round pipe section are externally fitted with detachable sleeves and secured with pipe clamps to connect them. The diameter of the inlet pipe increases from the end connected to the inlet straight pipe section to the end connected to the pre-inlet. The diameter of the connecting cone pipe increases from the end connected to the small round pipe section to the end connected to the large round pipe section. The connection is progressively larger at one end. First, the straight inlet pipe section and the large circular pipe section are connected by a sleeve and secured with pipe clamps, ensuring convenient disassembly and assembly of the connecting pipe between the pyrolysis furnace and the cyclone dust collector, facilitating maintenance. Second, the progressively changing diameter of the connecting conical pipe section and the inlet pipe ensures that the flow velocity of the pyrolysis gas gradually decreases as it flows from the pyrolysis furnace to the cyclone dust collector, preventing the pyrolysis gas from entering the cyclone dust collector at an excessively high velocity, which would affect the dust removal effect. Finally, when assembling and using the pyrolysis furnace and the cyclone dust collector, there is no need to consider whether the pre-inlet diameter matches the pyrolysis gas outlet diameter of the pyrolysis furnace; only the large circular pipe section, connecting conical pipe section, and small circular pipe section of suitable diameter need to be customized, improving the compatibility. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the pyrolysis gas treatment system in an embodiment of the present invention;

[0043] Figure 2 This is a front view of the dust removal device in an embodiment of the present invention;

[0044] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure along the AA direction;

[0045] Figure 4 for Figure 2 Schematic diagram of the cross-sectional structure in the middle BB direction;

[0046] Figure 5 This is a perspective view of the dust baffle at one angle in an embodiment of the present invention;

[0047] Figure 6 This is a schematic diagram of the structure of the dust removal filter element in an embodiment of the present invention;

[0048] Figure 7 for Figure 6 A schematic diagram of the cross-sectional structure along the CC direction;

[0049] Figure 8 for Figure 7 A magnified structural diagram of section D;

[0050] Figure 9 This is a perspective view of the dust removal filter element at one angle in an embodiment of the present invention;

[0051] Figure 10 This is a particle size distribution diagram of the pre-outlet dust of the cyclone dust collector of the present invention;

[0052] Figure 11 This is a particle size distribution diagram of the dust separated by the cyclone dust collector of the present invention;

[0053] Figure 12 This is a particle size distribution diagram of the dust separated by the terminal dust collector of the present invention.

[0054] In the picture:

[0055] 1. Crusher; 2. Screw conveyor; 3. Dryer; 4. Pyrolysis furnace;

[0056] 5. Cyclone dust collector; 51. Support frame; 52. Cyclone cylinder; 53. Cyclone cone;

[0057] 54. Air inlet duct; 541. Straight air inlet duct section; 542. Sleeve; 543. Large circular duct section; 544. Connecting conical duct section; 545. Small circular duct section;

[0058] 55. Exhaust box; 56. Motor; 57. First dust collection box; 58. Rotating plate; 59. Blades; 510. Core tube;

[0059] 6. Terminal dust collector; 61. Exhaust duct; 62. Terminal cylinder;

[0060] 63. Dust baffle; 631. Connecting plate; 632. Air outlet slot; 633. Air outlet opening; 634. Arc-shaped groove;

[0061] 64. Cover; 641. Large exhaust pipe; 642. Exhaust cone; 643. Small exhaust pipe;

[0062] 65. Sealing plate;

[0063] 66. Set ring plate; 661. Extension ring plate; 662. Circular slot; 663. Slot;

[0064] 67. Metal microporous membrane filter bag; 671. Limiting ring;

[0065] 68. Support frame; 681. Outward-folding rod;

[0066] 69. Second dust collection box;

[0067] 7. Hot air furnace. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the accompanying drawings of the embodiments of the present invention. Figure 1-9 The technical solutions of the embodiments of the present invention will be clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0069] In the existing technology, only a cyclone separator is used to remove dust from the pyrolysis gas generated by the pyrolysis furnace 4. The particle size distribution of the dust at the pre-outlet of the cyclone dust collector 5 and the particle size distribution of the dust collected by the cyclone dust collector 5 are analyzed. The results are as follows: Figure 10 and Figure 11 As shown, it is clear that the dust particles in the pyrolysis gas are small in size and have a wide distribution range. The cyclone dust collector 5 has a high dust removal efficiency for large particles larger than 10μm in the pyrolysis gas, while it is difficult to efficiently separate smaller particles using the cyclone dust collector 5.

[0070] like Figure 1As shown, the present invention provides a pyrolysis gas treatment system, comprising a crusher 1, a screw conveyor 2, a dryer 3, a pyrolysis furnace 4, a dust removal device, and a hot air furnace 7, arranged in sequence. The crusher 1, screw conveyor 2, dryer 3, pyrolysis furnace 4, and hot air furnace 7 are all existing technologies and can be directly purchased from the market according to actual needs.

[0071] The municipal solid waste, after being crushed by the crusher 1, is conveyed by the screw conveyor 2 to the dryer 3 for drying. Then, it falls into the pyrolysis furnace 4 for pyrolysis. The pyrolysis gas generated by the pyrolysis furnace 4 is treated by a dust removal device and then introduced into the hot air furnace 7 for combustion. The hot gas generated by combustion is introduced into the pyrolysis furnace 4 from the bottom, indirectly contacting the municipal solid waste and providing the temperature required for the pyrolysis reaction. Then, the hot gas leaves the pyrolysis furnace 4 from the top and is introduced into the dryer 3 to dry the municipal solid waste entering the dryer 3. Afterward, the hot gas leaving the dryer 3 is introduced into an external exhaust gas treatment system for purification before being discharged into the atmosphere to avoid environmental pollution.

[0072] In this invention, the pyrolysis gas produced by the pyrolysis reaction is treated by a dust removal device and then supplied to the hot blast furnace 7 for combustion to generate the hot gas required for heating the pyrolysis reaction. Apart from the fuel gas required when the hot blast furnace 7 is started, no additional fuel gas is needed, which saves costs. The hot gas used in the pyrolysis reaction is then passed into the dryer 3 to dry the domestic waste entering the dryer 3, which fully recovers and utilizes the waste heat of the hot gas and saves energy.

[0073] like Figure 2 and Figure 3 As shown, the dust removal device includes a cyclone dust collector 5, which is used to pre-treat the pyrolysis gas to remove large-particle dust larger than 10 μm. The cyclone dust collector 5 includes a support 51, a cyclone cylinder 52 mounted vertically on the support 51, and a cyclone cone 53 arranged vertically and welded to the bottom of the cyclone cylinder 52. The diameter of the cyclone cone 53 decreases from top to bottom. The bottom of the cyclone cone 53 is a pre-dust outlet for large-particle dust to flow out. A first dust collection box 57 is pulled out and placed below the pre-dust outlet to collect the large-particle dust flowing out from the pre-dust outlet.

[0074] like Figure 2As shown, a pre-inlet for supplying pyrolysis gas is opened at the top of the side wall of the cyclone cylinder 52 along a direction tangential to the cyclone cylinder 52. The pre-inlet is connected to the pyrolysis gas outlet of the pyrolysis furnace 4 through a pre-inlet pipe. The pre-inlet pipe includes an air inlet pipe 54 connected to the pre-inlet, an air inlet straight pipe section 541 connected to the other end of the air inlet pipe 54, a small round pipe section 545 connected to the pyrolysis gas outlet of the pyrolysis furnace 4, a connecting cone pipe section 544 connected to the other end of the small round pipe section 545, and a connecting cone pipe section 544 connected to the other end of the connecting cone pipe section 544. The large circular pipe section 543 and the inlet straight pipe section 541 have the same diameter as the large circular pipe section 543. The inlet straight pipe section 541 and the large circular pipe section 543 are externally detachable sleeves 542, which are fastened by pipe clamps to connect the inlet straight pipe section 541 and the large circular pipe section 543. The diameter of the inlet pipe 54 increases from the end connected to the inlet straight pipe section 541 to the end connected to the pre-inlet. The diameter of the connecting tapered pipe section 544 increases from the end connected to the small circular pipe section 545 to the end connected to the large circular pipe section 543. The straight inlet pipe section 541 and the large circular pipe section 543 are connected by a sleeve 542 and secured with a pipe clamp, ensuring convenient disassembly and assembly of the connecting pipe between the pyrolysis furnace 4 and the cyclone dust collector 5, facilitating maintenance. Secondly, the progressively changing diameter of the connecting conical pipe section 544 and the inlet pipe 54 ensures that the flow velocity of the pyrolysis gas gradually decreases as it flows from the pyrolysis furnace 4 to the cyclone dust collector 5, preventing the pyrolysis gas from entering the cyclone dust collector 5 at an excessively high velocity, which would affect the dust removal effect. Finally, when assembling and using the pyrolysis furnace 4 and the cyclone dust collector 5, there is no need to consider whether the pre-inlet diameter matches the pyrolysis gas outlet diameter of the pyrolysis furnace 4; only a suitable diameter large circular pipe section 543, connecting conical pipe section 544, and small circular pipe section 545 need to be customized, improving the compatibility.

[0075] like Figure 3 As shown, the top of the cyclone cylinder 52 is sealed by welding a circular plate. A core tube 510 is welded through the center of the circular plate, and the top of the core tube 510 is connected to a welded exhaust box 55. A motor 56 is installed on the top of the exhaust box 55, and the output shaft of the motor 56 moves vertically downwards through the top of the exhaust box 55, ensuring that the output shaft of the motor 56 can rotate freely when the motor 56 is turned on. A rotating plate 58 is welded horizontally to the bottom of the output shaft of the motor 56, and eight blades 59 are evenly arranged and welded to the bottom of the rotating plate 58. When the motor 56 is turned on, it drives the rotating plate 58 to rotate together with the blades 59, which speeds up the extraction of pyrolysis gas and improves filtration efficiency. The pyrolysis gas that enters the cyclone cylinder 52 through the pre-inlet rotates around the core tube 510 inside the cyclone cylinder 52. Under centrifugal force, large-diameter dust particles are separated out, fall into the cyclone cone 53, and finally flow out through the pre-dust outlet into the first dust collection box 57.

[0076] like Figure 2As shown, the dust removal device also includes a terminal dust collector 6 mounted on the bracket 51 and connected between the cyclone dust collector 5 and the hot air furnace 7. The terminal dust collector 6 is used to perform final dust removal treatment on the pyrolysis gas after pre-dust removal treatment to remove the remaining small-particle dust in the pyrolysis gas.

[0077] like Figure 4 As shown, the terminal dust collector 6 includes a terminal cylinder 62 mounted vertically on a bracket 51. A terminal inlet is located on the upper end of its side wall for the pyrolysis gas after pre-dust removal treatment to enter. An exhaust box 55 is connected to the terminal inlet via an exhaust pipe 61. A conical section is vertically connected to the bottom of the terminal cylinder 62, with the diameter decreasing from top to bottom. The bottom of the conical section is a terminal dust outlet for small-diameter dust particles to flow out. A second dust collection box 69 is pulled out below the terminal dust outlet to collect small-diameter dust particles flowing out of the terminal dust outlet.

[0078] like Figure 1 and Figure 2 As shown, the top of the terminal cylinder 62 is the terminal outlet for the pyrolysis gas. A cover 64 for sealing the terminal outlet is bolted to the top of the terminal cylinder 62. A large gas outlet pipe 641 is welded to the cover 64. A gas outlet cone pipe 642 is welded to the other end of the large gas outlet pipe 641. A small gas outlet pipe 643 is welded to the other end of the gas outlet cone pipe 642. The diameter of the gas outlet cone pipe 642 decreases from the end connected to the large gas outlet pipe 641 to the other end. The small gas outlet pipe 643 is connected to the hot blast stove 7, which can accelerate the speed at which the pyrolysis gas is injected into the hot blast stove 7, which is conducive to faster and more complete combustion in the hot blast stove 7.

[0079] like Figure 4 As shown, when the terminal cylinder 62 and the cover 64 are connected by bolts, the cover plate 65 is clamped and fixed between them. A metal microporous membrane filter bag 67 is movably installed through the cover plate 65. The metal microporous membrane filter bag 67 is detachably connected to the cover plate 65, and the metal microporous membrane filter bag 67 is suspended inside the terminal cylinder 62 along the axial direction of the terminal cylinder 62. The installation and connection between the cover 64 and the terminal cylinder 62 achieves the purpose of clamping and fixing the cover plate 65, thereby achieving the purpose of fixing the metal microporous membrane filter bag 67. The installation and disassembly are convenient, facilitating the regular cleaning and replacement of the metal microporous membrane filter bag 67.

[0080] A dust baffle plate 63 is welded to the inner wall of the terminal cylinder 62. It is located between the terminal inlet and the metal microporous membrane filter bag 67. The dust baffle plate 63 is arranged along the axial direction of the terminal cylinder 62. The upper parts of both ends of the dust baffle plate 63 are connected to the inner wall of the terminal cylinder 62 through the connecting plate 631. The terminal inlet corresponds to the upper part of the dust baffle plate 63. An air outlet slot 632 is opened through the connecting plate 631. Several air outlet holes 633 are evenly opened through the lower part of the dust baffle plate 63. The pyrolysis gas enters the terminal cylinder 62 from the terminal inlet. It first directly impacts the upper part of the dust baffle 63 and then disperses. Part of it passes through the air outlet slot 632 and splits into two streams that flow around the metal microporous membrane filter bag 67 in opposite directions. Part of it passes through the air outlet hole 633 and flows in the direction of impacting the metal microporous membrane filter bag 67. Part of it flows straight down until it passes the bottom of the dust baffle 63, and then flows upward to wrap around the metal microporous membrane filter bag 67. This makes the pyrolysis gas evenly dispersed before it is filtered by the metal microporous membrane filter bag 67. The metal microporous membrane filter bag 67 can filter out dust particles smaller than 10μm in the pyrolysis gas while improving filtration efficiency and effect.

[0081] like Figure 5 As shown, the middle part of the dust baffle 63 is bent towards the terminal cylinder 62 to form an arc-shaped groove 634 that matches the outer wall of the metal microporous membrane filter bag 67. This ensures that the portion of the pyrolysis gas flowing through the outlet opening 633 impacts the metal microporous membrane filter bag 67 radially, achieving better uniform dispersion and filtration. Simultaneously, the presence of the arc-shaped groove 634 reduces the volume of space formed between the dust baffle 63 and the terminal cylinder 62, thereby accelerating the flow rate of the pyrolysis gas within this space and improving filtration efficiency.

[0082] like Figure 5 As shown, the two ends of the dust baffle 63 are bent toward the direction of the terminal cylinder 62 to form an outward flange 635, and the connecting plate 631 is connected to the upper part of the outward flange 635. The presence of the outward-turned edge 635 creates a groove between the dust baffle plate 63 and the outward-turned edge 635, achieving the effects of air gathering and air guiding. This ensures that the groove is always filled with flowing pyrolysis gas. Part of the pyrolysis gas overflows from the upper part of the outward-turned edge 635, passes through the air outlet slot 632, and flows around the metal microporous membrane filter bag 67. Part of the pyrolysis gas overflows from the lower part of the outward-turned edge 635 and flows around the metal microporous membrane filter bag 67. Part of the pyrolysis gas flows through the air outlet opening 633 located at the lower part of the dust baffle plate 63 and flows in the direction of impacting the metal microporous membrane filter bag 67. Part of the pyrolysis gas flows through the groove until it passes the bottom of the dust baffle plate 63 and disperses upward in the direction of wrapping the metal microporous membrane filter bag 67. This helps to further evenly disperse the pyrolysis gas, thereby achieving a more efficient and better filtration effect.

[0083] like Figure 4 , Figure 6-8 As shown, a mounting hole is formed through the center of the sealing plate 65. A fitting ring plate 66 is welded around the mounting hole at the top of the sealing plate 65, and an extension ring plate 661 is welded around the mounting hole at the bottom of the fitting ring plate 66. The outer circumferential sidewall of the extension ring plate 661 abuts tightly against the inner circumferential sidewall of the mounting hole to ensure good sealing. A circular slot 662 is formed along the circumferential direction at the top of the inner circumferential sidewall of the fitting ring plate 66. A limiting ring 671 is sewn and welded to the top of the metal microporous membrane filter bag 67 by turning it outward and wrapping it. The limiting ring 671 can be snapped into the circular slot 662. By inserting / removing the limiting ring 671 into the circular slot 662, the metal microporous membrane filter bag 67 can be quickly disassembled and assembled, and then cleaned or replaced. The disassembly and assembly are convenient, facilitating regular cleaning or replacement and ensuring that good filtration effect is maintained continuously.

[0084] like Figure 8 and Figure 9 As shown, six slots 663 are evenly distributed around the top of the mounting ring plate 66, extending radially along the mounting ring plate 66. A detachable support frame 68 is suspended on the mounting ring plate 66. The support frame 68 is located inside the metal microporous membrane filter bag 67 to prevent the metal microporous membrane filter bag 67 from deforming due to airflow impact. Six outward-turning rods 681 are evenly welded to the top of the support frame 68, and the outward-turning rods 681 can be inserted into the slots 663. The support frame 68 provides support (maintains) for the shape of the metal microporous membrane filter bag 67, preventing it from easily deforming due to the impact of pyrolysis gas flow, and ensuring that the filtration performance of the metal microporous membrane filter bag 67 remains good. By inserting / removing the outward-folding rod 681 into the slot 663, the support frame 68 can be quickly assembled and disassembled, ensuring convenient assembly and disassembly. At the same time, the outward-folding rod 681 presses against the top of the limiting ring 671, effectively preventing the limiting ring 671 from coming out of the circular slot 662, thus improving the installation firmness and reliability of the metal microporous membrane filter bag 67.

[0085] A method for treating pyrolysis gas, using the aforementioned pyrolysis gas treatment system, includes the following steps:

[0086] Household waste is fed into crusher 1, where it is crushed and then conveyed by screw conveyor 2 to dryer 3 for drying. The crushed and dried waste is then fed into pyrolysis furnace 4 for pyrolysis, generating pyrolysis gas.

[0087] The pyrolysis gas flows sequentially through the small circular pipe section 545, the connecting conical pipe section 544, the large circular pipe section 543, the sleeve 542, the inlet straight pipe section 541, and the inlet pipe 54, finally flowing into the cyclone dust collector 5 through the pre-inlet for pre-dust removal. By gradually changing the diameter of the connecting conical pipe section 544 and the inlet pipe 54, the flow velocity of the pyrolysis gas gradually decreases as it flows from the pyrolysis furnace 4 to the cyclone dust collector 5, preventing the pyrolysis gas from entering the cyclone dust collector 5 at an excessively high velocity, which would affect the dust removal effect. Furthermore, when assembling and using the pyrolysis furnace 4 and the cyclone dust collector 5, there is no need to consider whether the diameter of the pre-inlet matches the diameter of the pyrolysis gas outlet of the pyrolysis furnace 4; only the appropriately sized large circular pipe section 543, connecting conical pipe section 544, and small circular pipe section 545 need to be customized, improving compatibility and enhancing practicality. Large dust particles larger than 10μm separated out flow out through the pre-dust outlet and into the first dust collection box 57. Then, the pyrolysis gas flows out through the pre-outlet.

[0088] The pyrolysis gas flows through the outlet pipe 61, passes through the terminal inlet and flows into the terminal cylinder 62, directly colliding with the upper part of the dust baffle 63. A portion of the pyrolysis gas overflows from the upper part of the outer flange 635, passing through the outlet slot 632 and flowing around the metal microporous membrane filter bag 67. Another portion overflows from the lower part of the outer flange 635 and flows around the metal microporous membrane filter bag 67. Simultaneously, a portion of the pyrolysis gas flows through the outlet opening 633 located at the lower part of the dust baffle 63 and flows radially towards the metal microporous membrane filter bag 67. A third portion flows through the tank until it passes the bottom of the dust baffle 63, then upwards and surrounds the metal microporous membrane filter bag 67, dispersing in all directions. The pyrolysis gas is fully and evenly dispersed before being filtered by the metal microporous membrane filter bag 67, achieving a more efficient and better filtration effect.

[0089] The remaining small dust particles (less than 10 μm) in the pyrolysis gas are blocked by the metal microporous membrane filter bag 67 and flow out through the terminal dust outlet into the second dust collection box 69. Figure 12 As shown, the above conclusion can be clearly demonstrated. The pyrolysis gas entering the metal microporous membrane filter bag 67 eventually flows out through the terminal outlet and into the hot air furnace 7 for combustion. The heat generated by combustion is supplied to the pyrolysis furnace 4.

[0090] The hot gas used in pyrolysis is passed into dryer 3 to dry the domestic waste entering dryer 3, which fully recovers and utilizes the waste heat of the hot gas and saves energy.

[0091] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0092] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0093] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0094] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature. In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0095] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A pyrolysis gas treatment system, comprising a pyrolysis furnace, a dust removal device and a hot air furnace, wherein the pyrolysis gas generated from the pyrolysis of domestic waste in the pyrolysis furnace is treated by the dust removal device and then introduced into the hot air furnace for combustion, and the hot gas generated by combustion is introduced into the pyrolysis furnace to provide the temperature required for the pyrolysis reaction. The dust removal device includes a cyclone dust collector, which is used to remove large-particle dust with a diameter of 10μm or more from the pyrolysis gas. The cyclone dust collector has a pre-inlet for the pyrolysis gas to enter, a pre-dust outlet for the large-particle dust to flow out, and a pre-outlet for the pyrolysis gas to flow out. Its features are, The dust removal device further includes a terminal dust collector disposed between the cyclone dust collector and the hot air furnace, which is used to remove residual small-particle dust in the pyrolysis gas; the terminal dust collector includes: The terminal cylinder has a terminal inlet for the pyrolysis gas after pre-dust removal treatment to enter, a terminal dust outlet for the small-diameter dust to flow out, and a terminal outlet for the pyrolysis gas to flow out. The terminal dust outlet and the terminal outlet are located at the bottom and top of the terminal cylinder, respectively, and the terminal inlet is located on the side wall of the terminal cylinder. The cover is detachably mounted on the top of the terminal cylinder and connected to the hot air furnace via a pipe; The sealing plate is held and fixed by the terminal cylinder and the sealing cap; A metal microporous membrane filter bag is movable through a sealing plate and its top is detachably connected to the sealing plate, so that the metal microporous membrane filter bag is suspended in the terminal cylinder along the axial direction of the terminal cylinder; The dust baffle is installed on the inner wall of the terminal cylinder and located between the terminal inlet and the metal microporous membrane filter bag. The dust baffle is arranged along the axial direction of the terminal cylinder. The upper parts of both ends of the dust baffle are connected to the inner wall of the terminal cylinder through connecting plates. The terminal inlet corresponds to the upper part of the dust baffle. An air outlet slot is opened through the connecting plate, and several air outlet holes are evenly opened through the lower part of the dust baffle. The dust baffle plate is bent in the middle towards the terminal cylinder to form an arc-shaped groove that matches the outer wall of the metal microporous membrane filter bag. This allows the pyrolysis gas passing through the air outlet to impact the outer wall of the metal microporous membrane filter bag radially, while reducing the volume of space formed between the dust baffle plate and the terminal cylinder. The dust baffle plate is bent at both ends toward the direction of the terminal cylinder to form an outward flange, and the connecting plate is connected to the upper part of the outward flange.

2. The pyrolysis gas treatment system according to claim 1, characterized in that, An installation hole is formed through the center of the sealing plate. A fitting ring plate is set around the installation hole on the top of the sealing plate. A circular slot is formed on the fitting ring plate. A limiting ring is set on the top of the metal microporous membrane filter bag. The limiting ring is detachably set in the circular slot.

3. The pyrolysis gas treatment system according to claim 2, characterized in that, The supporting frame is detachably suspended on the ring plate of the set. The supporting frame is located inside the metal microporous membrane filter bag to prevent the metal microporous membrane filter bag from being deformed by the impact of airflow.

4. The pyrolysis gas treatment system according to claim 3, characterized in that, The top of the mounting ring plate has several slots evenly spaced along the circumferential direction. The slots are arranged radially along the mounting ring plate. The top of the support frame has several outward-folding rods evenly spaced, and the outward-folding rods are inserted into the slots.

5. The pyrolysis gas treatment system according to claim 1, characterized in that, The pre-inlet is connected to the pyrolysis gas outlet of the pyrolysis furnace via a pre-inlet pipe. The pre-inlet pipe includes an air inlet pipe connected to the pre-inlet, an air inlet straight pipe section connected to the other end of the air inlet pipe, a small round pipe section connected to the pyrolysis gas outlet of the pyrolysis furnace, a connecting cone pipe section connected to the other end of the small round pipe section, and a large round pipe section connected to the other end of the connecting cone pipe section. The diameters of the air inlet straight pipe section and the large round pipe section are equal. The air inlet straight pipe section and the large round pipe section are externally fitted with detachable sleeves and secured with pipe clamps to connect the air inlet straight pipe section and the large round pipe section. The diameter of the air inlet pipe increases from the end connected to the air inlet straight pipe section to the end connected to the pre-inlet, and the diameter of the connecting cone pipe section increases from the end connected to the small round pipe section to the end connected to the large round pipe section.

6. A method for treating pyrolysis gas, characterized in that, The pyrolysis gas is processed using the pyrolysis gas treatment system as described in any one of claims 1-5.

7. The pyrolysis gas treatment method according to claim 6, characterized in that, Includes the following: After being crushed and dried, the domestic waste is fed into a pyrolysis furnace for pyrolysis treatment, generating pyrolysis gas. The gas flows into a cyclone dust collector through a pre-inlet for pre-dust removal. Large dust particles larger than 10μm flow out through the pre-dust outlet, and then the pyrolysis gas flows out through the pre-outlet. Pyrolysis gas flows into the terminal cylinder through the terminal inlet and collides directly with the upper part of the dust baffle. After the collision, the pyrolysis gas flows in all directions. Part of it passes through the air outlet slot and splits into two streams that flow around the metal microporous membrane filter bag. Part of it passes through the air outlet and flows in the direction of impacting the metal microporous membrane filter bag. Part of it flows straight down until it passes the bottom of the dust baffle and then flows upward to wrap around the metal microporous membrane filter bag. The remaining small dust particles smaller than 10μm in the pyrolysis gas are blocked by the metal microporous membrane filter bag and flow out through the terminal dust outlet. The pyrolysis gas that enters the metal microporous membrane filter bag finally flows out through the terminal outlet and into the hot air furnace for combustion. The heat generated by combustion is supplied to the pyrolysis furnace.

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