System for coupling and strengthening dechlorination of gasification synthesis gas

Abstract

This invention provides a system for coupled and enhanced dechlorination of syngas, comprising a gasifier, a fire-tube boiler, a dechlorination device, a syngas injection mechanism, and a fly ash filter connected in series. The gasifier is used to gasify raw materials to generate high-temperature syngas. The input end of the fire-tube boiler is connected to the gasifier. A dechlorinating agent feeding unit provides dechlorinating agent. The dechlorination tower includes a tower body, and the dechlorinating agent feeding unit is connected to the tower body through an injection pipe. The tower body is provided with a perforated plate distribution structure above the injection pipe and a swirl mixing structure above the perforated plate distribution structure. The input end of the syngas injection mechanism is connected to the output end of the fire-tube boiler, and the output end is connected to the bottom of the tower body and located below the injection pipe. The fly ash filter is connected to the output end of the dechlorination tower. This invention effectively improves the dechlorination efficiency of syngas, solves the problems of equipment corrosion and salt accumulation, reduces the consumption and cost of dechlorinating agent, solves the fly ash problem, and adapts to the dechlorination needs of high-chlorine biomass and other raw materials.

Description

Technical Field

[0001] This utility model belongs to the field of biomass energy conversion technology, and in particular relates to a system for enhanced dechlorination coupled with gasification syngas. Background Technology

[0002] Syngas is a gaseous mixture produced through the thermochemical conversion of carbonaceous feedstocks (such as coal, natural gas, and biomass). Its main components are carbon monoxide (CO) and hydrogen (H2). The process includes four core stages: feedstock processing, gasification / reforming, purification and conditioning, and downstream conversion. The pathways differ depending on the feedstock. Because the feedstock contains chlorine, the gasified syngas contains impurities such as chlorine. This can lead to reduced catalyst activity and lifespan, salt buildup and corrosion in equipment and pipelines, product quality and process safety issues, and environmental compliance problems.

[0003] Currently, biomass, as a renewable resource, has attracted much attention due to its large yield, ease of acquisition, advanced conversion technology, and high efficiency and cleanliness, especially with the increasing demand for green energy (such as green methanol and green jet fuel) in recent years. However, biomass and other raw materials have a much higher chlorine content than traditional coal, approximately 5-10 times higher, which causes greater corrosion damage to equipment after biomass gasification, making material selection difficult or costly, reducing equipment lifespan, or increasing system safety risks. It is necessary to add a dechlorination device upstream of biomass gasification to remove chloride ions from the syngas, protect downstream equipment, reduce chlorine-containing wastewater discharge, and stabilize system operation.

[0004] Existing dechlorination methods are mainly divided into wet scrubbing and dry adsorption. Wet scrubbing involves spraying alkaline solutions or water for dechlorination, but it has the following problems: high water content in the outlet gas of the dechlorination tower affects subsequent operations; chloride ions are introduced into the water system, requiring upgrades to water system equipment and piping materials, increasing investment; chloride ion corrosion poses equipment safety risks; and chloride ion removal efficiency is low. Dry adsorption uses a fixed-bed reactor filled with a dechlorinating agent for dechlorination. Although it has environmental and energy-saving advantages such as no water spraying, no cooling, and no new pollution sources, it also has the following drawbacks: inconvenient replacement of the dechlorinating agent in the dechlorination tower; small reaction contact area, resulting in low dechlorination efficiency; and large equipment pressure loss.

[0005] In existing dry dechlorination technologies, patent CN118491277A proposes a dry dechlorination system for blast furnace gas, using powdered dechlorinating agents. This significantly increases the contact area between the dechlorinating agent and the gas. A spiral conduit is also used to increase the reaction time and improve the dechlorination effect. However, this method is prone to causing clumping of the powdered dechlorinating agent, dead zones in the flow, and excessive deflection, leading to blockages. Patent CN111378801B proposes a process and device for removing hydrogen chloride from blast furnace gas pipelines by injecting powdered dechlorinating agents. While this eliminates the need for an additional dechlorination tower, the mixing effect between the powdered dechlorinating agent and the blast furnace gas is problematic, and the contact time is only 1-2 seconds, insufficient for a complete reaction. Subsequent contact with the bag filter surface for 2-3 hours continues the reaction, but for the large amount of fly ash in biomass syngas, the continued reaction effect on the bag filter surface is limited.

[0006] Furthermore, traditional dechlorination methods suffer from low efficiency, incomplete reactions, and a high excess ratio of dechlorinating agent. Many dechlorination devices on the market have altered their original process routes, resulting in large-scale design changes and introducing new, difficult-to-handle problems. If a dechlorination tower process is not used, the original process primarily relies on a water washing tower for dechlorination. However, the chlorine content of the liquid after washing is extremely high, making equipment material selection and manufacturing difficult. Simultaneously, all equipment from the high-pressure fly ash filter to the water washing tower needs to consider corrosion prevention due to the high chlorine gas content. Finally, the liquid treatment load after washing is high, easily causing environmental problems. Biomass gasification syngas contains a large amount of fly ash, and traditional dechlorination methods easily lead to problems such as fly ash water absorption, fly ash accumulation, fly ash adhesion, and fly ash entrainment gas precipitation.

[0007] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Utility Model Content

[0008] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a system for coupled enhanced dechlorination of gasification syngas, which can effectively remove chloride ions from gasification syngas, reduce equipment corrosion and salt accumulation, reduce the consumption and cost of dechlorination agents, avoid the discharge of chlorine-containing wastewater, solve the fly ash problem, and meet the dechlorination needs of biomass raw materials with high chlorine content.

[0009] To achieve the above and other related objectives, this utility model provides a system for coupled enhanced dechlorination of gasification syngas, the system comprising a gasifier, a fire-tube boiler, a dechlorination device, a syngas injection mechanism, and a fly ash filter connected in series.

[0010] The gasifier is used to gasify raw materials to generate high-temperature syngas.

[0011] The input end of the fire-tube boiler is connected to the gasifier, and the high-temperature syngas enters the fire-tube boiler for heat recovery and cooling.

[0012] The dechlorination device includes a dechlorinating agent feeding unit and a dechlorination tower; wherein, the dechlorinating agent feeding unit is used to provide dechlorinating agent; the dechlorination tower includes a tower body, the dechlorinating agent feeding unit is connected to the tower body through an injection pipe, the output end of the injection pipe is located in the inner cavity of the tower body, and the dechlorinating agent feeding unit injects dechlorinating agent into the tower body through the injection pipe; the tower body is also provided with an orifice plate uniform distribution structure and a swirl mixing structure, the orifice plate uniform distribution structure is located above the injection pipe, and the swirl mixing structure is located above the orifice plate uniform distribution structure;

[0013] The input end of the syngas injection mechanism is connected to the output end of the fire-tube boiler. The output end of the syngas injection mechanism is connected to the bottom of the tower body and located below the injection pipe. The cooled syngas is injected into the tower body through the syngas injection mechanism. The gas-solid mixture formed by the syngas and the dechlorinating agent is fully and evenly distributed through the orifice plate distribution structure and then enters the swirl mixing structure for full mixing and reaction.

[0014] The fly ash filter is connected to the output end of the dechlorination tower via a pipeline. The dechlorinated syngas enters the fly ash filter, which is used to separate fly ash from the syngas.

[0015] Preferably, the dechlorination feeding unit includes an atmospheric pressure chamber, a lock hopper, and a feeding tank connected sequentially from top to bottom via pipelines; the atmospheric pressure chamber is used to fill the dechlorination agent, the lock hopper is used to control the pressurized delivery of the dechlorination agent, the pressurization of the lock hopper causes the dechlorination agent in the atmospheric pressure chamber to enter the feeding tank, the feeding tank is connected to the tower body through the injection pipe, and the dechlorination agent in the feeding tank is injected into the tower body through the injection pipe under pressure.

[0016] Preferably, the input end of the injection pipe is also connected to a carrier gas pipeline, which is used to provide carrier gas, and the carrier gas carries the dechlorinating agent and injects it into the tower body; and the output end of the injection pipe is located in the inner cavity of the tower body, the output end of the injection pipe is bent downward, and the dechlorinating agent is injected downward from the output end of the injection pipe.

[0017] Preferably, the perforated plate is horizontally arranged on the inner wall of the tower body. The perforated plate is disc-shaped and has multiple sieve holes evenly distributed. The outlet of each sieve hole is provided with a chamfer, the angle of which is 30° to 75°, so as to allow the airflow after passing through the hole to diffuse to the surrounding area.

[0018] Preferably, the outer edge of the orifice plate uniformly distributed structure is provided with a plurality of openings, and the plurality of openings are equidistantly arranged along the outer edge of the orifice plate uniformly distributed structure to prevent solid accumulation between the inner wall of the tower body and the orifice plate uniformly distributed structure.

[0019] Preferably, the swirl mixing structure includes multiple swirl plates, which are equidistantly installed in the tower body and are arranged alternately in opposite directions along the axial direction of the tower body.

[0020] Preferably, the swirl plate includes a central disk and multiple fixed rings. The central disk and the multiple fixed rings are arranged concentrically. Multiple blades are evenly distributed around the circumference between the central disk and the adjacent fixed rings. Multiple blades are also evenly installed around the circumference between two adjacent fixed rings, and each blade is installed at the same oblique angle.

[0021] Preferably, a Venturi structure is further provided between the orifice plate uniform distribution structure and the swirl mixing structure, the Venturi structure being used to increase the backmixing of the gas-solid mixture.

[0022] Preferably, the output end of the syngas injection mechanism is connected to the lower section of the tower body. The syngas injection mechanism includes 1 to 8 interconnected pipes. The diameter of the multiple pipes gradually increases from the input end to the output end. The diameter of the pipes adjacent to the lower section of the tower body is the same as the diameter of the lower section of the tower body.

[0023] Preferably, the syngas injection mechanism includes multiple syngas injection pipes located on the same plane and arranged tangentially along the tower body. The input ends of the multiple syngas injection pipes are respectively connected to the output end of the fire-tube boiler. Syngas enters the tower body tangentially along the multiple syngas injection pipes and forms a rotating flow.

[0024] As described above, the gasification-syngas coupled enhanced dechlorination system of this invention has the following beneficial effects:

[0025] This invention provides a high-efficiency, environmentally friendly, and economical dechlorination device. Without altering the original process route, a dechlorination device is added between the fire-tube boiler and the fly ash filter. The process is simple, the equipment is basic, and it can effectively remove chloride ions from the gasification syngas. At the same time, the existing fly ash filter has an interception effect on dry powder dechlorination agent and fly ash, eliminating the need for additional separation equipment. It can also effectively solve the problems of equipment corrosion and salt accumulation, reduce the consumption and cost of dechlorination agent, reduce the discharge of chlorine-containing wastewater, meet the dechlorination requirements of high-chlorine-content biomass raw materials, thereby protecting downstream equipment and stabilizing system operation.

[0026] This invention employs a carrier gas to inject the dechlorinating agent countercurrently into the dechlorination tower, achieving countercurrent injection of dry powder dechlorinating agent and mixing with a large amount of syngas. This increases turbulence, enhances the uniformity and sufficiency of contact between the dechlorinating agent and the syngas, and significantly improves the dechlorination effect. The multiple pipelines of the syngas injection mechanism are progressively enlarged to reduce the gas velocity of the syngas entering the tower, thereby strengthening the uniform distribution of the syngas in the tower, reducing the impact on the tower, increasing the residence time in the tower, and further improving the dechlorination efficiency.

[0027] In addition, the unique structural design of the dechlorination tower greatly reduces the dead zone range of accumulated solids, further enhancing the mixing and reaction efficiency of syngas and dechlorinating agent, and reducing the excess ratio of dechlorinating agent and the total consumption; the uniformly distributed perforated plate structure achieves full uniform distribution and mixing of syngas and dry powder dechlorinating agent; the alternating forward and reverse swirling mixing structure increases airflow disturbance, making it difficult for fly ash to accumulate and adhere, while increasing the contact area between syngas and dechlorinating agent and increasing residence time to increase reaction time, thereby improving dechlorination efficiency; the Venturi structure causes a certain degree of backmixing between dry powder dechlorinating agent and syngas, making the particles more dispersed and further enhancing the mixing effect. Attached Figure Description

[0028] Figure 1 The diagram shown is a schematic representation of the system structure of enhanced dechlorination coupled with gasification syngas in a specific embodiment of this utility model.

[0029] Figure 2 The diagram shows a three-dimensional structural schematic (a) and a cross-sectional structural schematic (b) of the syngas injection mechanism and dechlorination tower in Embodiment 1 of this utility model.

[0030] Figure 3 The diagram shows a three-dimensional structural schematic (a) and a cross-sectional structural schematic (b) of the syngas injection mechanism and dechlorination tower in Embodiment 2 of this utility model.

[0031] Figure 4 The diagram shown is a schematic diagram of the synthesis gas injection mechanism in Embodiment 2 of this utility model.

[0032] Figure 5 The diagram shown is a structural schematic of the perforated plate uniformly distributed structure in a specific embodiment of this utility model.

[0033] Figure 6 The diagram shown is an enlarged view of the sieve holes in a specific embodiment of this utility model.

[0034] Figure 7 The diagram shown is a structural schematic of the positive swirling flow plate in a specific embodiment of this utility model.

[0035] Figure 8 The diagram shown is a structural schematic of the anti-swirl plate in a specific embodiment of this utility model.

[0036] Component designation explanation

[0037] 1 Gasification furnace

[0038] 2 Fire-tube boilers

[0039] 301 Bag Filter

[0040] 302 Atmospheric Pressure Warehouse

[0041] 303 Lock Bucket

[0042] 304 feed tank

[0043] 4. Injection pipe

[0044] 5. Carrier gas pipeline

[0045] 6. Dechlorination tower

[0046] 601 Tower

[0047] 6011 Perforated Plate Uniformly Distributed Structure

[0048] 60111 sieve aperture

[0049] α chamfer

[0050] 60112 Opening

[0051] 6012 Venturi Structure

[0052] 6013 Circular Swirl Plate

[0053] 60131 Central Plate

[0054] 60132 Retaining Ring

[0055] 60133 blade

[0056] 6014 Anti-Swirl Plate

[0057] 602 Upper Head

[0058] 603 Lower end cap

[0059] 7 Syngas injection mechanism

[0060] 701 Syngas injection pipeline

[0061] 8. Fly ash filter Detailed Implementation

[0062] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0063] Before further describing the specific embodiments of this utility model, it should be understood that the scope of protection of this utility model is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of this utility model is for describing specific embodiments and not for limiting the scope of protection of this utility model. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.

[0064] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise specified in this invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, equipment, and materials similar to or equivalent to those described, used, and materials in the embodiments of this invention may be used to implement this invention.

[0065] Please see Figures 1-8 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. Therefore, the drawings only show the components related to this utility model and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0066] Based on the current new operating conditions in the field of biomass gasification, including harsh conditions such as working pressure up to 4.2 MPa, working temperature up to 320℃, and chlorine content up to 1000 ppm or more, this utility model provides a system for coupled enhanced dechlorination of gasification syngas. (See reference...) Figure 1 The system includes a gasifier 1, a fire-tube boiler 2, a dechlorination unit, a syngas injection mechanism 7, and a fly ash filter 8 connected in series.

[0067] Gasifier 1 is used to gasify raw materials to generate high-temperature syngas;

[0068] The input end of the fire-tube boiler 2 is connected to the gasifier 1, and the high-temperature syngas enters the fire-tube boiler 2 for heat recovery and cooling.

[0069] The dechlorination device includes a dechlorinating agent feeding unit and a dechlorination tower 6; wherein, the dechlorinating agent feeding unit is used to provide dechlorinating agent; the dechlorination tower 6 includes a tower body 601, the dechlorinating agent feeding unit is connected to the tower body 601 through an injection pipe 4, the output end of the injection pipe 4 is located in the inner cavity of the tower body 601, and the dechlorinating agent feeding unit injects dechlorinating agent into the tower body 601 through the injection pipe 4; the tower body 601 is also provided with an orifice plate uniform distribution structure 6011 and a swirl mixing structure, the orifice plate uniform distribution structure 6011 is located above the injection pipe 4, and the swirl mixing structure is located above the orifice plate uniform distribution structure 6011;

[0070] The input end of the syngas injection mechanism 7 is connected to the output end of the fire-tube boiler 2. The output end of the syngas injection mechanism 7 is connected to the bottom of the tower body 601 and located below the injection pipe 4. The cooled syngas is injected into the tower body 601 through the syngas injection mechanism 7. The gas-solid mixture formed by the syngas and the dechlorinating agent is fully and evenly distributed through the orifice plate uniform distribution structure 6011, and then enters the swirl mixing structure for full mixing and reaction.

[0071] The fly ash filter 8 is connected to the output end of the dechlorination tower 6 through a pipeline. The dechlorinated synthesis gas enters the fly ash filter 8, which is used to separate fly ash from the synthesis gas.

[0072] For details, please refer to Figure 2 The dechlorination tower 6 includes a tower body 601 and an upper head 602. An outlet is provided on the upper head 602, and the outlet is connected to the fly ash filter 8 via a pipe. (See also...) Figure 3 The dechlorination tower 6 includes a tower body 601, an upper end cap 602, and a lower end cap 603. In a specific embodiment of this utility model, the diameter of the dechlorination tower 6 is 300mm to 5000mm, preferably 1400mm to 1800mm, and the diameter of the dechlorination tower 6 is the same as the diameter of the tower body 601. The height of the tower body 601 is 8m to 30m, preferably 12m to 16m. The residence time of the synthesis gas in the dechlorination tower 6 is greater than 5s, preferably 6s to 9s.

[0073] In addition, the tower body 601 is equipped with a perforated plate distribution structure 6011 and a swirl mixing structure, which are mainly used to fully distribute and mix the gas-solid mixture after mixing, increase disturbance, increase contact area, and increase residence time to increase reaction time, thereby improving reaction efficiency.

[0074] As an example, the dechlorination feeding unit includes an atmospheric pressure chamber 302, a lock hopper 303, and a feed tank 304 connected sequentially from top to bottom via pipelines. The atmospheric pressure chamber 302 is used to fill the dechlorinating agent, and the lock hopper 303 is used to control the pressurized delivery of the dechlorinating agent. Pressurizing the lock hopper 303 causes the dechlorinating agent in the atmospheric pressure chamber 302 to enter the feed tank 304. The feed tank 304 is connected to the tower body 601 through an injection pipe 4. Under pressure, the dechlorinating agent in the feed tank 304 is injected into the tower body 601 through the injection pipe 4.

[0075] Specifically, a bag filter 301 is installed above the atmospheric pressure silo 302. Depressurized air from the lock hopper 303 enters the bag filter 301. The dechlorinating agent filtered by the bag filter 301 enters the atmospheric pressure silo 302 through a rotary valve. The rotary valve is installed on the pipeline between the bag filter 301 and the atmospheric pressure silo 302. The inlet of the rotary valve receives the discharge from the bag filter 301, and the outlet of the rotary valve is connected to the inlet of the atmospheric pressure silo 302. Rotation of the rotary valve causes the filtered dechlorinating agent to re-enter the atmospheric pressure silo 302. The specific structure of the rotary valve is not described in detail here. In addition, the dechlorination feeding unit also includes a level gauge, an air replenisher, and a fluidization device, which will not be elaborated upon here.

[0076] As an example, the input end of the injection pipe 4 is also connected to a carrier gas pipe 5, which is used to provide carrier gas. The carrier gas carries the dechlorinating agent and is injected into the tower body 601. The output end of the injection pipe 4 is located in the inner cavity of the tower body 601. The output end of the injection pipe 4 is bent downwards, and the dechlorinating agent is injected downwards from the output end of the injection pipe 4.

[0077] Specifically, the dechlorinating agent in the feed tank 304 enters the inner cavity of the tower body 601 under pressure through the injection pipe 4. A carrier gas pipe 5 is added before the inlet of the injection pipe to increase the gas velocity of the dechlorinating agent entering the tower body 601. The volume flow ratio of the carrier gas to the synthesis gas is 1:(100~500).

[0078] See Figure 2 The injection pipe 4 is a straight pipe perpendicular to the tower body 601. The output end of the injection pipe 4 extends into the tower body 601 and bends downward to achieve countercurrent injection of dry powder dechlorinating agent, increase disturbance, and improve the uniformity and sufficiency of contact between the dechlorinating agent and the synthesis gas. The diameter of the injection pipe 4 needs to be determined according to the carrier gas volume and the dechlorinating agent dosage to ensure the gas flow rate. The gas velocity of the carrier gas carrying the dechlorinating agent injected into the tower body 601 is 2 to 15 m / s, preferably 5 to 8 m / s, to enhance the spray dispersion and uniformity.

[0079] Preferably, the injection pipe 4 extends to the central axis of the tower body 601 to reduce the impact of syngas deviation on the reduced mixing effect.

[0080] In a specific embodiment of this utility model, the horizontal position of the injection pipe 4 is 500mm to 2500mm from the lower tangent of the tower body 601, preferably 900mm to 2100mm. See also Figure 2 The lower tangent line of tower body 601 refers to the plane line where the connection between tower body 601 and syngas injection mechanism 7 is located. (See reference...) Figure 3 The lower tangent of tower body 601 is the plane line where the lower end cap 603 connects to tower body 601.

[0081] As an example, the perforated plate uniform distribution structure 6011 is arranged laterally on the inner wall of the tower body 601. The perforated plate uniform distribution structure 6011 is disc-shaped and has multiple sieve holes 60111 evenly opened. The outlet of each sieve hole 60111 is provided with a chamfer α, the angle of which is 30° to 75°, so as to realize that the airflow after passing through the hole diffuses to the surrounding area.

[0082] For details, please refer to Figure 5 , Figure 6 The chamfer α at the outlet of the sieve hole 60111 is 30° to 75°, preferably 45° to 60°, so that the airflow after passing through the sieve hole 60111 can diffuse to the surrounding area, ensuring that there is no dead zone with solid accumulation on the upper surface of the perforated plate.

[0083] In a specific embodiment of this utility model, the diameter of the sieve hole 60111 is 4mm to 40mm, preferably 20mm to 30mm.

[0084] In a specific embodiment of this utility model, the center distance between two adjacent sieve holes 60111 is 1.5 to 3 times the diameter of the sieve hole 60111.

[0085] As an example, a plurality of openings 60112 are provided on the outer edge of the orifice plate uniform distribution structure 6011. The plurality of openings 60112 are equidistantly arranged along the outer edge of the orifice plate uniform distribution structure 6011 to prevent solid accumulation between the inner wall of the tower body 601 and the orifice plate uniform distribution structure 6011.

[0086] For details, please refer to Figure 5 Multiple openings 60112 are provided on the outer edge of the perforated plate uniformly distributed structure 6011 to prevent solids from accumulating between the inner wall of the tower body 601 and the sieve holes 60111. In a specific embodiment of this utility model, the diameter of the openings 60112 is 10mm to 30mm, and the number of openings 60112 is 15 to 90 equidistantly arranged around the perimeter, preferably 30 to 45 equidistantly arranged.

[0087] In a specific embodiment of this utility model, the distance between the orifice plate uniform distribution structure 6011 and the horizontal position of the injection pipe 4 is 300mm to 800mm.

[0088] As an example, the swirl mixing structure includes multiple swirl plates, which are equidistantly installed inside the tower body 601, and the multiple swirl plates are alternately arranged in opposite directions along the axial direction of the tower body 601.

[0089] Specifically, multiple swirl plates are arranged alternately in opposite directions, meaning the swirl mixing structure is a combination of alternating forward and reverse swirl plates 6013 and 6014. These alternating swirl plates enable alternating acceleration and deceleration of the gas-solid mixture, alternating forward and reverse rotation, and a combination of revolution and rotation. This not only facilitates contact and reaction between the dechlorinating agent and the gas but also enhances the desorption effect of fly ash, making it difficult for fly ash to accumulate and adhere, thus improving the overall treatment effect. Preferably, the swirl mixing structure includes 2 to 8 swirl plates, more preferably 3 to 5.

[0090] In a specific embodiment of this utility model, see [reference]. Figure 2 , Figure 3 The swirling mixing structure includes four swirling plates. A forward swirling plate 6013 is arranged adjacent to the Venturi structure 6012, and upwards, there are reverse swirling plates 6014, forward swirling plates 6013, and reverse swirling plates 6014.

[0091] In a specific embodiment of this utility model, the distance between two adjacent swirl plates is 500mm to 5000mm, and the distance between the swirl plate at the bottom and the upper surface of the Venturi structure 6012 is 500mm to 3000mm.

[0092] As an example, the swirl plate includes a central disk 60131 and multiple fixed rings 60132. The central disk 60131 and the multiple fixed rings 60132 are arranged concentrically. Multiple blades 60133 are evenly distributed around the circumference between the central disk 60131 and the adjacent fixed rings 60132. Multiple blades 60133 are also evenly installed around the circumference between two adjacent fixed rings 60132, and each blade 60133 is installed at the same oblique angle.

[0093] Specifically, if the inner diameter of the tower is too large, in order to avoid the phenomenon of denser inner and sparser outer blades 60133, the swirl plate is divided into multiple segments, and multiple fixing rings 60132 are set from the inside out. Preferably, 2 to 4 fixing rings 60132 are set, so that the swirl plate is divided into 2 to 4 segments with inner circles and outer rings. The number of blades 60133 on the outer fixing ring 60132 is greater than the number of blades 60133 on the adjacent inner fixing ring 60132. Preferably, the number of blades 60133 on the outer fixing ring 60132 is 1.5 to 5 times the number of blades 60133 on the adjacent inner fixing ring 60132.

[0094] See Figure 7 , Figure 8The diagrams show the structures of the forward-swirling swirl plate 6013 and the reverse-swirling swirl plate 6014, respectively. The tilt angle of the blades 60133 on the forward-swirling swirl plate 6013 is opposite to that on the reverse-swirling swirl plate 6014.

[0095] In a specific embodiment of this utility model, the inner diameter of the central disk 60131 is 30mm to 100mm to reduce the vortex at the tower center and reduce kinetic energy loss. The thickness of the fixing ring 60132 is 20mm to 200mm, the thickness of the blade 60133 is 1mm to 5mm, the inclination angle of the blade 60133 is 10° to 60°, preferably 15° to 30°. A smaller inclination angle of the blade 60133 helps to prevent particle accumulation. The radial angle of the blade 60133 is 10° to 25°. Here, the inclination angle of the blade 60133 refers to the angle between the blade 60133 and the plane of the swirl plate, and the radial angle of the blade 60133 refers to the angle of the blade 60133 in the radial direction.

[0096] As an example, a Venturi structure 6012 is also provided between the orifice plate uniform distribution structure 6011 and the swirl mixing structure. The Venturi structure 6012 is used to increase the backmixing of the gas-solid mixture.

[0097] Specifically, gas-solid mixture refers to the mixture of dry powder dechlorination agent and syngas. Backmixing refers to the mixing and redistribution of particles or fluid elements in the flow direction during fluid flow. In other words, backmixing means that particles not only move along the flow direction during flow, but also mix and redistribute in the lateral or reverse direction. The Venturi structure 6012 can make the dry powder dechlorination agent more uniformly dispersed and enhance the mixing effect between the dechlorination agent and syngas.

[0098] In a specific embodiment of this utility model, the Venturi structure 6012 includes a contraction section, a throat, and a diffusion section from bottom to top. The throat and diffusion section generate strong turbulence. The throat is the junction of the contraction section and the diffusion section. The diameter of the Venturi structure 6012 is 30% to 90% of the diameter of the tower body 601, that is, the diameter of the throat is 30% to 90% of the diameter of the tower body 601. Preferably, the diameter of the Venturi structure 6012 is 45% to 75% of the diameter of the tower body 601.

[0099] In a specific embodiment of this utility model, the distance between the lower end face of the Venturi structure 6012 and the horizontal position of the injection pipe 4 is 800mm to 1200mm.

[0100] As an example, the output end of the syngas injection mechanism 7 is connected to the lower cut surface of the tower body 601. The syngas injection mechanism 7 includes 1 to 8 interconnected pipes. The diameter of the multiple pipes gradually increases from the input end to the output end. The pipe diameter of the pipes adjacent to the lower cut surface of the tower body 601 is the same as the pipe diameter of the lower cut surface of the tower body 601.

[0101] Specifically, the syngas injection mechanism 7 includes 1 to 8 interconnected pipelines (e.g., any number of segments such as 1, 2, 4, 6, 8, etc.).

[0102] See Figure 2 The input end of the syngas injection mechanism 7 is connected to the fire-tube boiler 2 via a bend, and the output end is connected to the bottom end of the tower body 601. It is configured as a progressively expanding pipe to reduce the syngas velocity, ensuring it enters the tower body 601 at a velocity of 2–10 m / s. This enhances uniform distribution within the tower body 601, reduces impact on the internal components, and increases residence time. To avoid excessive diameter differences, uneven gas distribution, flow deviation, and backflow caused by a single expansion, the syngas injection mechanism 7 preferably undergoes 2–4 progressively expanding stages.

[0103] As an example, the syngas injection mechanism 7 includes multiple syngas injection pipes 701, which are located on the same plane and are all arranged tangentially along the tower body 601. The input ends of the multiple syngas injection pipes 701 are respectively connected to the output end of the fire-tube boiler 2. Syngas enters the tower body 601 tangentially along the multiple syngas injection pipes 701 and forms a rotating flow.

[0104] See Figure 3 and see Figure 4 In a specific embodiment of this utility model, the syngas injection mechanism 7 includes four syngas injection pipes 701. Each syngas injection pipe 701 is arranged tangentially along the tower body 601 and located on the same plane. The four syngas injection pipes 701 are evenly distributed around the circumference of the tower body 601, and their output ends are all connected to the tower body 601. Syngas enters tangentially from the bottom of the tower body 601 to form a rotating flow. Preferably, the syngas injection pipe 701 is 500mm to 800mm away from the lower tangent of the tower body 601.

[0105] The raw materials used for gasification syngas in this invention can be coal, petroleum coke, biomass, municipal waste, or waste liquid. It adopts the existing gasification waste boiler process, in which the gasifier 1 realizes raw material gasification at the top and radiant heat recovery at the bottom, then convective heat recovery through the fire-tube boiler 2, and then separation of syngas and fly ash through the fly ash filter 8. The gasification syngas coupled enhanced dechlorination method in this invention involves inserting a dechlorination device between the fire-tube boiler 2 and the fly ash filter 8 in the gasification waste boiler process.

[0106] This invention provides a method for enhanced dechlorination of gasification syngas using the above-described system, comprising the following steps:

[0107] S1. The high-temperature syngas generated in the gasifier 1 enters the fire-tube boiler 2. The fire-tube boiler 2 cools down the high-temperature syngas. The cooled syngas is injected into the tower body 601 through the syngas injection mechanism 7 to obtain pre-dechlorinated syngas.

[0108] S2. Add the dechlorinating agent to the atmospheric pressure chamber 302 of the dechlorinating agent feeding unit. Pressurize the lock hopper 303 to make the dechlorinating agent in the atmospheric pressure chamber 302 enter the feeding tank 304. Under pressure, the dechlorinating agent in the feeding tank 304 enters the tower body 601 through the injection pipe 4. At the same time, open the carrier gas pipeline 5. The carrier gas carries the dechlorinating agent and is injected into the tower body 601 through the injection pipe 4 at a certain flow rate.

[0109] S3. After the dechlorinating agent injected into the tower body 601 is initially mixed with the pre-dechlorinated syngas, it is fully and evenly distributed through the orifice plate uniform distribution structure 6011, and then enters the swirl mixing structure to fully dechlorinate the syngas.

[0110] S4. The dechlorinated syngas is fed into the fly ash filter 8, where fly ash, dechlorination agent, or reaction products are separated to obtain dechlorinated syngas. As an example, in step S2, the syngas is injected into the tower body 601 through the syngas injection mechanism 7 at a velocity of 2–10 m / s.

[0111] Specifically, the gas velocity of the syngas injected into the tower body 601 through the syngas injection mechanism 7 can be any value within the range of 2m / s, 4m / s, 6m / s, 8m / s, 10m / s, etc.

[0112] As an example, the dechlorination agent in step S2 has a mesh size of 32 to 1000 mesh.

[0113] Specifically, the mesh size of the dechlorinating agent can include any value within the range of 32 mesh, 40 mesh, 100 mesh, 300 mesh, 500 mesh, 700 mesh, 900 mesh, 1000 mesh, etc. Preferably, the mesh size of the dechlorinating agent is 200 mesh to 500 mesh (e.g., 200 mesh, 300 mesh, 400 mesh, 500 mesh, etc.). Fine particles of dechlorinating agent can increase the specific surface area and improve the reaction rate and efficiency between the dechlorinating agent and the syngas.

[0114] In specific embodiments of this utility model, the dechlorination agent includes one or a combination of calcium hydroxide, calcium oxide, calcium carbonate, potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate.

[0115] As an example, the carrier gas carrying the dechlorinating agent is injected into the tower body 601 at a velocity of 2 to 15 m / s.

[0116] Specifically, the velocity of the carrier gas carrying the dechlorinating agent injected into the tower body 601 can be any value within the range of 2m / s, 3m / s, 5m / s, 10m / s, 12m / s, 15m / s, etc.

[0117] To better understand the gasification-syngas coupled enhanced dechlorination system of this invention, the following description refers to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit this invention in any way.

[0118] Example 1

[0119] See Figure 1 and Figure 2 This embodiment provides a system for coupled enhanced dechlorination of gasified syngas, comprising a gasifier 1, a fire-tube boiler 2, a dechlorination device, a syngas injection mechanism 7, and a fly ash filter 8 connected in series. The gasifier 1 is used to gasify raw materials to generate high-temperature syngas. The input end of the fire-tube boiler 2 is connected to the gasifier 1, and the high-temperature syngas enters the fire-tube boiler 2 for heat recovery and cooling. The dechlorination device includes a dechlorinating agent feeding unit and a dechlorination tower 6 (see...). Figure 2 The dechlorination agent feeding unit is used to provide the dechlorination agent; the dechlorination tower 6 includes a tower body 601 (the diameter of the tower body 601 is 1400mm and the height of the tower body 601 is 14m), the dechlorination agent feeding unit is connected to the tower body 601 through the injection pipe 4, the output end of the injection pipe 4 is located in the inner cavity of the tower body 601, and the dechlorination agent feeding unit injects the dechlorination agent into the tower body 601 through the injection pipe 4; the tower body 601 is also provided with an orifice plate uniform distribution structure 6011 and a swirl mixing structure, the orifice plate uniform distribution structure 6011 is located above the injection pipe 4, and the swirl mixing structure is located below the orifice plate uniform distribution structure 6011. Above; the input end of the syngas injection mechanism 7 is connected to the output end of the fire-tube boiler 2, and the output end of the syngas injection mechanism 7 is connected to the bottom of the tower body 601 and located below the injection pipe 4. The cooled syngas is injected into the tower body 601 through the syngas injection mechanism 7. The gas-solid mixture formed by the syngas and the dechlorination agent is fully and evenly distributed through the perforated plate uniform distribution structure 6011, and then enters the swirl mixing structure for full mixing and reaction. The fly ash filter 8 is connected to the output end of the dechlorination tower 6 through a pipe. The dechlorinated syngas enters the fly ash filter 8, which is used to separate fly ash from the syngas.

[0120] In this embodiment, the dechlorination feeding unit includes a bag filter 301, an atmospheric pressure chamber 302, a lock hopper 303, and a feeding tank 304 connected sequentially from top to bottom via pipes. The atmospheric pressure chamber 302 is used to fill the dechlorinating agent, and the lock hopper 303 is used to control the pressurized delivery of the dechlorinating agent. Pressurization of the lock hopper 303 causes the dechlorinating agent in the atmospheric pressure chamber 302 to enter the feeding tank 304. Depressurization gas from the lock hopper 303 enters the bag filter 301. The dechlorinating agent filtered by the bag filter 301 enters the atmospheric pressure chamber 302 through a rotary valve. The feeding tank 304 is connected to the tower body 601 through an injection pipe 4. The dechlorinating agent in the feeding tank 304 is injected into the tower body 601 under pressure through the injection pipe 4.

[0121] In this embodiment, the diameter of the injection pipe 4 is 15mm. The injection pipe 4 is set perpendicular to the tower body 601. The distance between the injection pipe 4 and the lower tangent of the tower body 601 is 1000mm. The input end of the injection pipe 4 is also connected to a carrier gas pipeline 5, which is used to provide carrier gas. The carrier gas carries the dechlorinating agent and is injected into the tower body 601. The output end of the injection pipe 4 is located at the center of the inner cavity of the tower body 601. The output end of the injection pipe 4 is bent downwards, and the dechlorinating agent is injected downwards from the output end of the injection pipe 4.

[0122] In this embodiment, the orifice plate distribution structure 6011 is horizontally arranged on the inner wall of the tower body 601. The distance between the orifice plate distribution structure 6011 and the horizontal position of the injection pipe 4 is 500mm. The orifice plate distribution structure 6011 is disc-shaped and has a plurality of screen holes 60111 evenly opened. The diameter of the screen hole 60111 is 20mm. The center distance between two adjacent screen holes 60111 is 2.5 times the diameter of the screen hole 60111. The outlet of each screen hole 60111 is provided with a chamfer α. The angle of the chamfer α is 40°, which is used to make the airflow after passing through the hole diffuse to the surrounding area.

[0123] In this embodiment, 36 openings 60112 are provided on the outer edge of the perforated plate uniform distribution structure 6011. The 36 openings 60112 are equidistantly arranged along the outer edge of the perforated plate uniform distribution structure 6011, and the diameter of the openings 60112 is 20mm.

[0124] In this embodiment, the swirling mixing structure includes four swirling plates with a spacing of 3000mm between them. The four swirling plates are arranged alternately in opposite directions along the axial direction of the tower body 601, and the distance between the bottommost swirling plate and the upper surface of the Venturi structure 6012 is 800mm.

[0125] In this embodiment, the swirl plate includes a central disk 60131 and two fixing rings 60132. The inner diameter of the central disk 60131 is 60mm, and the thickness of the fixing rings 60132 is 28mm. The central disk 60131 and the two fixing rings 60132 are arranged concentrically. 30 blades 60133 are evenly distributed around the circumference between the central disk 60131 and the adjacent fixing rings 60132. 60 blades 60133 are also evenly installed around the circumference between two adjacent fixing rings 60132. The blades 60133 are 2mm thick, have an inclination angle of 25°, and a radial angle of 16.6°. Each blade 60133 is installed at the same oblique angle.

[0126] In this embodiment, a Venturi structure 6012 is also provided between the orifice plate uniform distribution structure 6011 and the swirl mixing structure. The diameter of the Venturi structure 6012 is 650mm, and the distance between the lower end face of the Venturi structure 6012 and the horizontal position of the injection pipe 4 is 1000mm. The Venturi structure 6012 is used to increase the back mixing of the gas-solid mixture.

[0127] In this embodiment, refer to Figure 2 The output end of the syngas injection mechanism 7 is connected to the lower cut surface of the tower body 601. The syngas injection mechanism 7 includes two interconnected pipes. The diameter of the two pipes gradually increases from the input end to the output end. The diameter of the pipe adjacent to the lower cut surface of the tower body 601 is the same as the diameter of the lower cut surface of the tower body 601.

[0128] Example 2

[0129] See Figure 1 and Figure 3 This embodiment provides a system for enhanced dechlorination coupled with gasification syngas. The difference between this system and Embodiment 1 is that the distance between the injection pipe 4 and the lower tangent of the tower body 601 is 2000mm; the syngas injection mechanism 7 includes four syngas injection pipes 701 (see...). Figure 4 The four syngas injection pipes 701 are located on the same plane and are all arranged tangentially along the tower body 601. The input ends of the four syngas injection pipes 701 are respectively connected to the output end of the fire-tube boiler 2. Syngas enters the tower body 601 tangentially along the four syngas injection pipes 701 and forms a rotating flow. The distance between the four syngas injection pipes 701 and the lower tangent of the tower body 601 is 800mm. Other structures are the same as in Embodiment 1 and will not be described again here.

[0130] In summary, this invention provides a highly efficient, environmentally friendly, and economical dechlorination device. Without altering the original process route, a dechlorination unit is added between the fire-tube boiler and the fly ash filter. The process is simple, the equipment is basic, and it effectively removes chloride ions from the gasified syngas. Simultaneously, the existing fly ash filter intercepts both the dry powder dechlorinating agent and fly ash, eliminating the need for additional separation equipment. This also effectively solves equipment corrosion and salt accumulation problems, reduces dechlorinating agent consumption and costs, and lowers chlorine-containing wastewater discharge, meeting the dechlorination requirements of high-chlorine-content biomass feedstocks. This protects downstream equipment and stabilizes system operation. This invention uses carrier gas to countercurrently inject the dechlorinating agent into the dechlorination tower, achieving countercurrent injection of the dry powder dechlorinating agent and mixing it with a large amount of syngas. This increases turbulence, enhances the uniformity and sufficiency of contact between the dechlorinating agent and the syngas, and significantly improves the dechlorination effect. The syngas injection mechanism's multiple pipes are progressively enlarged to reduce the gas velocity entering the tower, thereby strengthening the uniform distribution of syngas within the tower, reducing impact on the tower, and increasing residence time within the tower, further improving dechlorination efficiency. Furthermore, the unique structural design of the dechlorination tower significantly reduces the dead zone area for solid accumulation, further enhancing the mixing and reaction efficiency of syngas and dechlorinating agent, and reducing the excess ratio of dechlorinating agent and total consumption. The uniformly distributed perforated plate structure ensures thorough distribution and mixing of syngas and dry powder dechlorinating agent. The alternating forward and reverse swirling mixing structure increases airflow turbulence, making it difficult for fly ash to accumulate and adhere, while simultaneously increasing the contact area and residence time between syngas and dechlorinating agent to increase reaction time, thereby improving dechlorination efficiency. The Venturi structure causes a certain degree of backmixing between the dry powder dechlorinating agent and syngas, resulting in more dispersed particles and further enhancing the mixing effect. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0131] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A system for coupled enhanced dechlorination of gasification syngas, characterized in that, The system includes a gasifier, a fire-tube boiler, a dechlorination unit, a syngas injection mechanism, and a fly ash filter connected in series. The gasifier is used to gasify raw materials to generate high-temperature syngas. The input end of the fire-tube boiler is connected to the gasifier, and the high-temperature syngas enters the fire-tube boiler for heat recovery and cooling. The dechlorination device includes a dechlorinating agent feeding unit and a dechlorination tower; wherein, the dechlorinating agent feeding unit is used to provide dechlorinating agent; the dechlorination tower includes a tower body, the dechlorinating agent feeding unit is connected to the tower body through an injection pipe, the output end of the injection pipe is located in the inner cavity of the tower body, and the dechlorinating agent feeding unit injects dechlorinating agent into the tower body through the injection pipe; the tower body is also provided with an orifice plate uniform distribution structure and a swirl mixing structure, the orifice plate uniform distribution structure is located above the injection pipe, and the swirl mixing structure is located above the orifice plate uniform distribution structure; The input end of the syngas injection mechanism is connected to the output end of the fire-tube boiler. The output end of the syngas injection mechanism is connected to the bottom of the tower body and located below the injection pipe. The cooled syngas is injected into the tower body through the syngas injection mechanism. The gas-solid mixture formed by the syngas and the dechlorinating agent is fully and evenly distributed through the orifice plate distribution structure and then enters the swirl mixing structure for full mixing and reaction. The fly ash filter is connected to the output end of the dechlorination tower via a pipeline. The dechlorinated syngas enters the fly ash filter, which is used to separate fly ash from the syngas.

2. The system for enhanced dechlorination coupled with gasification syngas according to claim 1, characterized in that: The dechlorination feeding unit includes an atmospheric pressure chamber, a lock hopper, and a feeding tank connected sequentially from top to bottom via pipelines. The atmospheric pressure chamber is used to fill the dechlorination agent, and the lock hopper is used to control the pressurized delivery of the dechlorination agent. The pressurization of the lock hopper causes the dechlorination agent in the atmospheric pressure chamber to enter the feeding tank. The feeding tank is connected to the tower body through the injection pipe, and the dechlorination agent in the feeding tank is injected into the tower body through the injection pipe under pressure.

3. The system for enhanced dechlorination coupled with gasification syngas according to claim 1, characterized in that: The input end of the injection pipe is also connected to a carrier gas pipeline, which is used to provide carrier gas. The carrier gas carries the dechlorinating agent and is injected into the tower body. The output end of the injection pipe is located in the inner cavity of the tower body. The output end of the injection pipe is bent downwards, and the dechlorinating agent is injected downwards from the output end of the injection pipe.

4. The system for enhanced dechlorination coupled with gasification syngas according to claim 1, characterized in that: The perforated plate is horizontally arranged on the inner wall of the tower body. The perforated plate is disc-shaped and has multiple sieve holes evenly distributed. The outlet of each sieve hole is chamfered with an angle of 30° to 75° to allow the airflow after passing through the holes to diffuse to the surrounding area.

5. The system for enhanced dechlorination coupled with gasification syngas according to claim 4, characterized in that: Multiple openings are provided on the outer edge of the orifice plate uniformly distributed structure, and the multiple openings are equidistantly arranged along the outer edge of the orifice plate uniformly distributed structure to prevent solid accumulation between the inner wall of the tower body and the orifice plate uniformly distributed structure.

6. The system for enhanced dechlorination coupled with gasification syngas according to claim 1, characterized in that: The swirling mixing structure includes multiple swirling plates, which are equidistantly installed inside the tower body, and the multiple swirling plates are alternately arranged in opposite directions along the axial direction of the tower body.

7. The system for enhanced dechlorination coupled with gasification syngas according to claim 6, characterized in that: The swirl plate includes a central disk and multiple fixed rings. The central disk and the multiple fixed rings are arranged concentrically. Multiple blades are evenly distributed around the circumference between the central disk and the adjacent fixed rings. Multiple blades are also evenly installed around the circumference between two adjacent fixed rings, and each blade is installed at the same oblique angle.

8. The system for enhanced dechlorination coupled with gasification syngas according to claim 1, characterized in that: A Venturi structure is also provided between the orifice plate uniform distribution structure and the swirl mixing structure. The Venturi structure is used to increase the backmixing of the gas-solid mixture.

9. The system for enhanced dechlorination coupled with gasification syngas according to claim 1, characterized in that: The output end of the syngas injection mechanism is connected to the lower section of the tower body. The syngas injection mechanism includes 1 to 8 interconnected pipes. The diameter of the pipes in the multiple pipes gradually increases from the input end to the output end. The diameter of the pipes adjacent to the lower section of the tower body is the same as the diameter of the lower section of the tower body.

10. The system for enhanced dechlorination coupled with gasification syngas according to claim 1, characterized in that: The syngas injection mechanism includes multiple syngas injection pipes located on the same plane and arranged tangentially along the tower body. The input ends of the multiple syngas injection pipes are respectively connected to the output end of the fire-tube boiler. Syngas enters the tower body tangentially along the multiple syngas injection pipes and forms a rotating flow.

Images