System and method for coupling enhanced dechlorination of gasified synthesis gas

Abstract

The invention provides a system and a method for coupling enhanced dechlorination of gasified synthesis gas. The system comprises a gasification furnace, a fire-tube boiler, a dechlorination device, a synthesis gas injection mechanism and a fly ash filter which are sequentially connected in series, the gasifier is used for gasifying raw materials to generate high-temperature synthesis gas; the input end of the fire-tube boiler is connected with the gasification furnace; the dechlorinating agent feeding unit provides a dechlorinating agent; the dechlorination tower comprises a tower body, and the dechlorination agent feeding unit is communicated with the tower body through a spraying pipeline; a pore plate uniform distribution structure positioned above the injection pipeline and a rotational flow mixing structure positioned above the pore plate uniform distribution structure are arranged in the tower body; the input end of the synthesis gas injection mechanism is connected with the output end of the fire-tube boiler, and the output end is communicated with the bottom of the tower body and positioned below the injection pipeline; the fly ash filter is connected with the output end of the dechlorination tower. According to the system, the dechlorination efficiency of the synthesis gas is effectively improved, the problems of equipment corrosion and salt deposition are solved, the consumption and cost of a dechlorination agent are reduced, the problem of fly ash is solved, and the system meets the dechlorination requirements of raw materials such as high-chlorine biomass.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass energy conversion, and in particular relates to a system and method for coupled enhanced dechlorination of gasification and synthesis gas. Background Art

[0002] Synthesis gas (syngas) is a gas mixture produced through the thermochemical conversion of carbon-containing 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 vary depending on the feedstock. Because the feedstocks contain chlorine, impurities such as chlorine are present in the gasified syngas. This can lead to reduced catalyst activity and lifespan, salt accumulation and corrosion in equipment and pipelines, product quality and process safety issues, and environmental compliance.

[0003] Biomass, as a renewable resource, is currently attracting significant attention due to its high yield, ease of access, technological advancements, and high efficiency and cleanliness. This is particularly true given the growing demand for green energy sources (such as green methanol and green jet fuel) in recent years. However, biomass and other raw materials contain significantly higher chlorine content than traditional coal, approximately 5-10 times more. This poses a greater risk of corrosion to equipment following biomass gasification, making equipment selection difficult or costly, reducing equipment lifespan, or increasing system safety risks. Therefore, it is necessary to add a dechlorination unit to the front end of biomass gasification to remove chloride ions from the synthesis gas, protect downstream equipment, reduce the discharge of chlorine-containing wastewater, and stabilize system operation.

[0004] Existing dechlorination methods are mainly divided into wet scrubbing and dry adsorption. The wet method involves dechlorination by spraying alkali solution, water, etc., but there are the following problems: the outlet gas of the dechlorination tower has a high water content, which affects subsequent operations; chloride ions are introduced into the water system, requiring upgrades to water system equipment and pipeline materials, increasing investment; chloride ion corrosion poses equipment safety risks; and the chloride ion removal efficiency is low. Dry adsorption dechlorination is carried out through a fixed-bed reactor filled with a dechlorination agent. 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 disadvantages: the dechlorination agent in the dechlorination tower is difficult to replace; the reaction contact surface is small, resulting in low dechlorination efficiency; and the equipment has large pressure loss.

[0005] Among existing dry dechlorination technologies, patent CN118491277A proposes a dry dechlorination system for blast furnace gas. This system utilizes a powdered dechlorinating agent, significantly increasing the contact area between the dechlorinating agent and the gas. A spiral staircase is also used to increase reaction time and enhance dechlorination effectiveness. However, this method can easily lead to agglomeration of the powdered dechlorinating agent, dead zones in the flow, and excessive deflection, leading to blockage. Patent CN111378801B proposes a process and apparatus for removing hydrogen chloride from blast furnace gas pipelines by spraying a powdered dechlorinating agent into the blast furnace gas pipeline. While this eliminates the need for a separate dechlorination tower, the mixing of the powdered dechlorinating agent and the blast furnace gas is problematic, and the contact time is only 1-2 seconds, insufficient for a full reaction. The subsequent reaction continues on the surface of a bag filter for 2-3 hours, but this limited reaction efficiency is limited for the large amount of fly ash in biomass syngas.

[0006] Furthermore, traditional dechlorination methods have low dechlorination efficiency, incomplete reactions, and a high excess of dechlorinating agents. Many dechlorination devices on the market have changed the original process route, resulting in large-scale design changes and the introduction of new and difficult-to-handle problems. Without a dechlorination tower, the original process primarily relies on a water scrubber for dechlorination. However, the chlorine content of the liquid after water washing is extremely high, making equipment selection and manufacturing difficult. Furthermore, all equipment, from high-pressure fly ash filters to water scrubbers, needs to consider corrosion protection against high-chlorine gases. Finally, the liquid handling load after water washing is high, which can easily cause environmental problems. Biomass gasification syngas contains a large amount of fly ash, and traditional dechlorination methods are prone to problems such as fly ash water absorption, fly ash accumulation, fly ash adhesion, and fly ash entrained gas precipitation.

[0007] Therefore, it is necessary to provide an improved technical solution to the above-mentioned deficiencies in the prior art. Summary of the Invention

[0008] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a system and method for coupled enhanced dechlorination of gasification synthesis gas, which can effectively remove chloride ions in gasification synthesis gas, reduce equipment corrosion and salt accumulation, reduce the consumption and cost of dechlorination agents, avoid the discharge of chlorine-containing wastewater, and solve the fly ash problem at the same time, so as to meet the dechlorination needs of high-chlorine content biomass feedstock.

[0009] To achieve the above-mentioned and other related objectives, the present invention provides a system for gasification and synthesis gas coupled with enhanced dechlorination, the system comprising a gasifier, a fire tube boiler, a dechlorination device, a synthesis gas injection mechanism, and a fly ash filter connected in series.

[0010] The gasifier is used to gasify raw materials to generate high-temperature synthesis gas;

[0011] The input end of the fire tube boiler is connected to the gasifier, and the high-temperature synthesis gas enters the fire tube boiler for heat recovery and temperature reduction;

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

[0013] The input end of the syngas injection mechanism is connected to the output end of the fire tube boiler, and the output end of the syngas injection mechanism is in communication with the bottom of the tower body and is 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 dechlorination agent is fully and evenly distributed through the orifice plate uniform distribution structure and then enters the cyclone mixing structure for full mixing and reaction.

[0014] The fly ash filter is connected to the output end of the dechlorination tower through a pipeline, and the dechlorinated synthesis gas enters the fly ash filter. The fly ash filter is used to separate fly ash from the synthesis gas.

[0015] Preferably, the dechlorination feeding unit includes a normal pressure bin, a lock hopper and a feeding tank which are connected in sequence from top to bottom by pipelines; the normal pressure bin is used to load the dechlorination agent, the lock hopper is used to control the pressurized delivery of the dechlorination agent, the lock hopper pressurizes the dechlorination agent in the normal pressure bin 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 sprayed 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 dechlorination agent and is injected into the tower body; and the output end of the injection pipe is arranged in the inner cavity of the tower body, and the output end of the injection pipe is bent downward, and the dechlorination agent is injected downward from the output end of the injection pipe.

[0017] Preferably, the orifice plate uniform distribution structure is horizontally arranged on the inner wall of the tower body. The orifice plate uniform distribution structure is disc-shaped and has multiple sieve holes evenly opened. The outlets of the sieve holes are all provided with chamfers, and the angle of the chamfer is 30° to 75°, so as to realize the diffusion of part of the airflow after passing through the hole to the surroundings.

[0018] Preferably, a plurality of openings are provided on the outer edge of the orifice plate uniformly distributed structure, 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 a plurality of swirl plates, the plurality of swirl plates are equidistantly installed in the tower body, and the plurality of swirl plates are alternately arranged in forward and reverse 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 on the circumference between the central disk and the adjacent fixed rings, and multiple blades are also evenly installed on 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 uniformly distributed orifice plate structure and the swirl mixing structure, and the Venturi structure is used to increase backmixing of the gas-solid mixture.

[0022] Preferably, the output end of the synthesis gas injection mechanism is connected to the lower cross-section of the tower body, and the synthesis gas injection mechanism includes 1 to 8 sections of interconnected pipelines. The diameters of the multiple sections of the pipelines gradually increase from the input end to the output end, and the diameter of the pipeline adjacent to the lower cross-section of the tower body is consistent with the diameter of the lower cross-section of the tower body.

[0023] Preferably, the synthesis gas injection mechanism includes multiple synthesis gas injection pipes, the multiple synthesis gas injection pipes are located in the same plane, and are all arranged along the tangent direction of the tower body. The input ends of the multiple synthesis gas injection pipes are respectively connected to the output ends of the fire tube boiler, and the synthesis gas enters the tower body tangentially along the multiple synthesis gas injection pipes and forms a rotating flow.

[0024] The present invention also provides a method for coupled enhanced dechlorination of gasification synthesis gas using the above system, comprising the following steps:

[0025] The high-temperature synthesis gas generated in the gasifier enters the fire tube boiler, which recovers heat and cools the high-temperature synthesis gas. The cooled synthesis gas is then injected into the tower body through the synthesis gas injection mechanism to obtain pre-dechlorinated synthesis gas.

[0026] The dechlorinating agent is added to the atmospheric pressure bin of the dechlorinating agent feeding unit, and the lock hopper is pressurized to allow the dechlorinating agent in the atmospheric pressure bin to enter the feeding tank. The dechlorinating agent in the feeding tank enters the tower body through the injection pipe under the action of pressure. At the same time, the carrier gas pipeline is opened, and the carrier gas carrying the dechlorinating agent is injected into the tower body through the injection pipe at a certain flow rate;

[0027] After the dechlorination agent injected into the tower body is preliminarily mixed with the pre-dechlorinated synthesis gas, it is fully and evenly distributed through the orifice plate uniform distribution structure, and then enters the cyclone mixing structure to fully dechlorinate the synthesis gas;

[0028] The dechlorinated synthesis gas is transported to the fly ash filter, and fly ash, dechlorinating agent or reaction product are separated by the fly ash filter to obtain dechlorinated synthesis gas.

[0029] As an example, the synthesis gas is injected into the tower body through the synthesis gas injection mechanism at a gas velocity of 2 to 10 m / s.

[0030] As an example, the mesh size of the dechlorination agent is 32 mesh to 1000 mesh.

[0031] As an example, the carrier gas carrying the dechlorination agent is injected into the tower body at a gas velocity of 2 to 15 m / s.

[0032] As described above, the system and method for coupled enhanced dechlorination of gasified syngas according to the present invention have the following beneficial effects:

[0033] The present invention provides an efficient, environmentally friendly and economical dechlorination method and device. On the basis of not changing 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 simple, and the chloride ions in the gasification synthesis gas can be effectively removed. At the same time, the original fly ash filter has an interception effect on the dry powder dechlorination agent and fly ash, and no additional separation equipment is required. It can also effectively solve the problems of equipment corrosion and salt accumulation, reduce the consumption and cost of the dechlorination agent, and reduce the discharge of chlorine-containing wastewater. It meets the dechlorination requirements of raw materials such as high-chlorine content biomass, thereby protecting subsequent equipment and stabilizing system operation.

[0034] The present invention uses a carrier gas to countercurrently inject the dechlorinating agent into the dechlorination tower, realizes the countercurrent injection of the dry powder dechlorinating agent and mixes it with a large amount of synthesis gas, increases disturbance, increases the uniformity and sufficiency of the contact between the dechlorinating agent and the synthesis gas, and significantly improves the dechlorination effect; the multiple pipelines of the synthesis gas injection mechanism are expanded in section by section, reducing the gas velocity of the synthesis gas entering the tower body, thereby enhancing the uniform distribution of the synthesis gas in the tower body, reducing the impact on the tower body, and increasing the residence time in the tower body, further improving the dechlorination efficiency.

[0035] In addition, the unique structural design of the dechlorination tower greatly reduces the dead zone range of accumulated solids, further enhances the mixing and reaction efficiency of the synthesis gas and dechlorinating agent, and reduces the excess ratio and total consumption of the dechlorinating agent; the setting of the uniformly distributed structure of the orifice plate realizes sufficient uniform distribution and mixing of the synthesis gas and the dry powder dechlorinating agent; the swirl mixing structure with alternating positive and negative settings increases the airflow disturbance, making it difficult for fly ash to accumulate and adhere, while increasing the contact area between the synthesis gas and the dechlorinating agent, increasing the residence time to increase the reaction time, and thus improving the dechlorination efficiency; the Venturi structure causes the dry powder dechlorinating agent and the synthesis gas to be back-mixed to a certain extent, making the particles more dispersed, further enhancing the mixing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1It shows a schematic diagram of the system structure of gasification synthesis gas coupled with enhanced dechlorination in a specific embodiment of the present invention.

[0037] Figure 2 Shown are a three-dimensional structural schematic diagram (a) and a cross-sectional structural schematic diagram (b) of the synthesis gas injection mechanism and the dechlorination tower in Example 1 of the present invention.

[0038] Figure 3 Shown are a three-dimensional structural schematic diagram (a) and a cross-sectional structural schematic diagram (b) of the synthesis gas injection mechanism and the dechlorination tower in Example 2 of the present invention.

[0039] Figure 4 It shows a schematic structural diagram of the synthesis gas injection mechanism in Example 2 of the present invention.

[0040] Figure 5 It shows a structural schematic diagram of the uniformly distributed structure of the orifice plates in a specific embodiment of the present invention.

[0041] Figure 6 Shown is an enlarged structural schematic diagram of the sieve holes in a specific embodiment of the present invention.

[0042] Figure 7 It shows a schematic structural diagram of a forward-spinning swirl plate in a specific embodiment of the present invention.

[0043] Figure 8 It is a schematic structural diagram of the counter-rotating swirl plate in a specific embodiment of the present invention.

[0044] Component number description

[0045] 1 Gasifier

[0046] 2 Fire tube boilers

[0047] 301 Bag Dust Collector

[0048] 302 Normal Pressure Warehouse

[0049] 303 Lock Bucket

[0050] 304 Feed Tank

[0051] 4 Spray into the pipe

[0052] 5 Carrier gas line

[0053] 6 Dechlorination Tower

[0054] 601 Tower

[0055] 6011 hole plate uniform distribution structure

[0056] 60111 sieve hole

[0057] α Chamfer

[0058] 60112 opening

[0059] 6012 Venturi structure

[0060] 6013 Forward swirl plate

[0061] 60131 Center Plate

[0062] 60132 fixing ring

[0063] 60133 blade

[0064] 6014 Counter-rotating swirl plate

[0065] 602 upper head

[0066] 603 lower head

[0067] 7 Synthesis gas injection mechanism

[0068] 701 Synthesis gas injection pipeline

[0069] 8 Fly ash filter DETAILED DESCRIPTION

[0070] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0071] Before further describing the specific embodiments of the present invention, it should be understood that the scope of the present invention is not limited to the specific embodiments described below. It should also be understood that the terminology used in the examples is intended to describe specific embodiments and is not intended to limit the scope of the present invention. The experimental procedures in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0072] When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the understanding of the prior art by those skilled in the art and the description of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention may also be used to implement the present invention.

[0073] See also Figures 1 to 8It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0074] Based on the new working conditions in the field of biomass gasification, the working pressure is as high as 4.2Mpa, the working temperature is as high as 320℃, and the chlorine content is as high as 1000ppm. The present invention provides a system for coupling gasification synthesis gas with enhanced dechlorination. Figure 1 The system comprises a gasifier 1, a fire tube boiler 2, a dechlorination device, a synthesis gas injection mechanism 7 and a fly ash filter 8 connected in series;

[0075] The gasifier 1 is used to gasify raw materials to generate high-temperature synthesis gas;

[0076] The input end of the fire tube boiler 2 is connected to the gasifier 1, and the high-temperature synthesis gas enters the fire tube boiler 2 for heat recovery and temperature reduction;

[0077] The dechlorination device includes a dechlorination agent feeding unit and a dechlorination tower 6; wherein the dechlorination agent feeding unit is used to provide a dechlorination agent; the dechlorination tower 6 includes a tower body 601, the dechlorination 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 dechlorination agent feeding unit sprays the dechlorination agent into the tower body 601 through the injection pipe 4; the tower body 601 is also provided with a uniformly distributed orifice plate structure 6011 and a swirl mixing structure, wherein the uniformly distributed orifice plate structure 6011 is located above the injection pipe 4, and the swirl mixing structure is located above the uniformly distributed orifice plate structure 6011;

[0078] 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 is 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 orifice plate uniform distribution structure 6011 and then enters the cyclone mixing structure for thorough mixing and reaction.

[0079] 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. The fly ash filter 8 is used to separate fly ash from the synthesis gas.

[0080] For details, see Figure 2 The dechlorination tower 6 includes a tower body 601 and an upper head 602. The upper head 602 is provided with an outlet, which is connected to the fly ash filter 8 through a pipeline; Figure 3The dechlorination tower 6 includes a tower body 601, an upper head 602 and a lower head 603. In a specific embodiment of the present invention, the diameter of the dechlorination tower 6 is 300 mm to 5000 mm, preferably, the diameter of the dechlorination tower 6 is 1400 mm to 1800 mm, and the diameter of the dechlorination tower 6 is the diameter of the tower body 601. The height of the tower body 601 is 8 m to 30 m, preferably, the height of the tower body 601 is 12 m to 16 m, and the residence time of the synthesis gas in the dechlorination tower 6 is greater than 5 s. Preferably, the residence time of the synthesis gas in the dechlorination tower 6 is 6 s to 9 s.

[0081] In addition, a hole plate uniform distribution structure 6011 and a swirl mixing structure are set in the tower body 601, which are mainly used to fully distribute and mix the mixed gas-solid mixture, increase disturbance, increase contact area, increase residence time to increase reaction time, thereby improving reaction efficiency.

[0082] As an example, the dechlorination feeding unit includes a normal pressure bin 302, a lock hopper 303 and a feeding tank 304 which are connected in sequence from top to bottom by pipelines; the normal pressure bin 302 is used to load the dechlorination agent, and the lock hopper 303 is used to control the pressurized delivery of the dechlorination agent. The lock hopper 303 pressurizes the dechlorination agent in the normal pressure bin 302 to enter the feeding tank 304. The feeding tank 304 is connected to the tower body 601 through the injection pipe 4. The dechlorination agent in the feeding tank 304 is sprayed into the tower body 601 through the injection pipe 4 under pressure.

[0083] Specifically, a bag dust collector 301 is also provided above the normal pressure bin 302, and the depressurized air from the lock hopper 303 enters the bag dust collector 301, and the dechlorination agent filtered by the bag dust collector 301 enters the normal pressure bin 302 through a rotary valve, wherein the rotary valve is installed on the pipeline between the bag dust collector 301 and the normal pressure bin 302, and the feed port of the rotary valve receives the discharge of the bag dust collector 301, and the discharge port of the rotary valve is connected to the feed port of the normal pressure bin 302, and the filtered dechlorination agent re-enters the normal pressure bin 302 through the rotation of the rotary valve; the specific structure of the rotary valve is not excessively restricted here; in addition, the dechlorination feeding unit also includes a level meter, an air replenisher, a fluidizing device, etc., which will not be elaborated on here.

[0084] As an example, the input end of the injection pipe 4 is also connected to the carrier gas pipeline 5, which is used to provide carrier gas, and the carrier gas carries the dechlorination agent and is sprayed into the tower body 601; and the output end of the injection pipe 4 is arranged in the inner cavity of the tower body 601, and the output end of the injection pipe 4 is bent downward, and the dechlorination agent is sprayed downward from the output end of the injection pipe 4.

[0085] Specifically, the dechlorinating agent in the feed tank 304 enters the inner cavity of the tower body 601 through the injection pipe 4 under pressure. A carrier gas pipeline 5 is added before the inlet of the injection pipeline 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).

[0086] See Figure 2 The injection pipe 4 is arranged as a straight pipe perpendicular to the tower body 601, and the output end of the injection pipe 4 extends into the interior of the tower body 601 and bends downward to realize the countercurrent injection of the dry powder dechlorination agent, increase the disturbance, and improve the uniformity and sufficiency of the contact between the countercurrent injected dechlorination agent and the synthesis gas; wherein, the diameter of the injection pipe 4 needs to be determined according to the carrier gas amount and the dechlorination dosage to ensure the gas flow rate, and the gas velocity of the carrier gas carrying the dechlorination agent into the tower body 601 is 2 to 15 m / s, preferably, the gas velocity is 5 to 8 m / s to enhance the dispersion and uniformity of the injection.

[0087] Preferably, the injection pipe 4 extends into the central axis of the tower body 601 to reduce the influence of the deflection of the synthesis gas on the reduction of the mixing effect.

[0088] In a specific embodiment of the present invention, the horizontal position of the injection pipe 4 is 500mm to 2500mm from the lower tangent line of the tower body 601, preferably 900mm to 2100mm. Figure 2 The lower tangent line of the tower body 601 refers to the plane line where the connection between the tower body 601 and the synthesis gas injection mechanism 7 is located. Figure 3 The lower tangent line of the tower body 601 is the plane line where the connection between the lower head 603 and the tower body 601 is located.

[0089] As an example, the orifice plate uniform distribution structure 6011 is horizontally arranged on the inner wall of the tower body 601. The orifice plate uniform distribution structure 6011 is disc-shaped and has multiple sieve holes 60111 evenly opened. The outlets of the sieve holes 60111 are all provided with chamfers α, and the angle of the chamfer α is 30° to 75°, so as to realize the diffusion of part of the air flow after passing through the hole to the surroundings.

[0090] For details, see Figure 5 、 Figure 6 The chamfer angle α of the outlet of the sieve hole 60111 is 30° to 75°, preferably 45° to 60°, so that the air flow after passing through the sieve hole 60111 can partially diffuse to the surroundings, ensuring that there is no dead area on the upper surface of the orifice plate where solids accumulate.

[0091] In a specific embodiment of the present invention, the diameter of the sieve hole 60111 is 4 mm to 40 mm. Preferably, the diameter of the sieve hole 60111 is 20 mm to 30 mm.

[0092] In a specific embodiment of the present invention, the center distance between two adjacent sieve holes 60111 is 1.5 to 3 times the diameter of the sieve hole 60111.

[0093] As an example, a plurality of openings 60112 are provided on the outer edge of the orifice plate uniformly distributed structure 6011 , and the plurality of openings 60112 are equidistantly arranged along the outer edge of the orifice plate uniformly distributed structure 6011 to prevent solid accumulation between the inner wall of the tower body 601 and the orifice plate uniformly distributed structure 6011 .

[0094] For details, see Figure 5 A plurality of openings 60112 are provided on the outer edge of the orifice plate uniformly distributed structure 6011 to prevent solid accumulation between the inner wall of the tower body 601 and the sieve holes 60111. In a specific embodiment of the present invention, the diameter of the openings 60112 is 10 mm to 30 mm, and the number of the openings 60112 is 15 to 90 equidistantly arranged around a circle, preferably, 30 to 45 equidistantly arranged.

[0095] In a specific embodiment of the present invention, the distance between the orifice plate uniform distribution structure 6011 and the horizontal position of the injection pipe 4 is 300 mm to 800 mm.

[0096] As an example, the swirl mixing structure includes a plurality of swirl plates, which are equidistantly installed in the tower body 601 , and are alternately arranged in forward and reverse directions along the axial direction of the tower body 601 .

[0097] Specifically, multiple swirl plates are arranged in alternating forward and reverse directions, i.e., the swirl mixing structure comprises a combination of alternating forward-swirl plates 6013 and reverse-swirl plates 6014. These alternating forward and reverse swirl plates enable the gas-solid mixture to undergo alternating acceleration and deceleration, alternating forward and reverse rotation, and a combination of revolution and rotation. This not only enables contact and reaction between the dechlorination agent and the gas, but also enhances fly ash desorption, preventing fly ash from accumulating and adhering, thereby improving the overall treatment effect. Preferably, the swirl mixing structure includes 2 to 8 swirl plates, preferably 3 to 5.

[0098] In the specific embodiment of the present invention, see Figure 2 、 Figure 3 The swirl mixing structure includes four swirl plates, a forward swirl plate 6013 is arranged adjacent to the venturi structure 6012, and upwards there are reverse swirl plates 6014, forward swirl plates 6013, and reverse swirl plates 6014.

[0099] In a specific embodiment of the present invention, the distance between two adjacent swirl plates is 500 mm to 5000 mm, and the distance between the swirl plate at the lowest end and the upper surface of the Venturi structure 6012 is 500 mm to 3000 mm.

[0100] 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 on the circumference between the central disk 60131 and the adjacent fixed rings 60132. Multiple blades 60133 are also evenly installed on the circumference between two adjacent fixed rings 60132, and each blade 60133 is installed at the same oblique angle.

[0101] Specifically, if the inner diameter of the tower is too large, in order to avoid the phenomenon that the blades 60133 are dense inside and sparse outside, the swirl plate is divided into multiple sections, and multiple fixing rings 60132 are set from the inside to the outside. Preferably, 2 to 4 fixing rings 60132 are set, so that the swirl plate is divided into 2 to 4 sections with inner circle and outer ring; the number of blades 60133 located 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 located on the outer fixing ring 60132 is 1.5 to 5 times the number of blades 60133 on the adjacent inner fixing ring 60132.

[0102] See Figure 7 、 Figure 8 They are schematic structural diagrams of the forward-rotating swirl plate 6013 and the reverse-rotating swirl plate 6014 , respectively. The inclination angle of the blades 60133 on the forward-rotating swirl plate 6013 is opposite to the inclination angle of the blades 60133 on the reverse-rotating swirl plate 6014 .

[0103] In a specific embodiment of the present invention, the inner diameter of the center disk 60131 is 30 mm to 100 mm to reduce vortex formation in the center of the tower and reduce kinetic energy loss. The thickness of the retaining ring 60132 is 20 mm to 200 mm. The thickness of the blades 60133 is 1 mm to 5 mm. The inclination angle of the blades 60133 is 10° to 60°, preferably 15° to 30°. A smaller inclination angle of the blades 60133 is beneficial for preventing particle accumulation. The radial angle of the blades 60133 is 10° to 25°. The inclination angle of the blades 60133 refers to the angle between the blades 60133 and the plane of the swirl plate, and the radial angle of the blades 60133 refers to the angle of the blades 60133 in the radial direction.

[0104] As an example, a venturi structure 6012 is further provided between the orifice plate uniform distribution structure 6011 and the swirl mixing structure. The venturi structure 6012 is used to increase the back mixing of the gas-solid mixture.

[0105] Specifically, the gas-solid mixture refers to a mixture of dry powder dechlorinating agent and synthesis gas. Backmixing refers to a certain degree of mixing and redistribution of particles or fluid elements in the flow direction during fluid flow. That is, 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 setting of the Venturi structure 6012 can make the dry powder dechlorinating agent more evenly dispersed, thereby enhancing the mixing effect between the dechlorinating agent and the synthesis gas.

[0106] In a specific embodiment of the present invention, the venturi structure 6012 includes a contraction section, a throat and a diffusion section from bottom to top. The throat and the diffusion section will generate strong turbulence. The throat is the junction of the contraction section and the diffusion section. The variable diameter of the venturi structure 6012 is 30% to 90% of the diameter of the tower body 601, which means that the diameter of the throat is 30% to 90% of the diameter of the tower body 601. Preferably, the variable diameter of the venturi structure 6012 is 45% to 75% of the diameter of the tower body 601.

[0107] In a specific embodiment of the present invention, the distance between the lower end surface of the venturi structure 6012 and the horizontal position of the injection pipe 4 is 800 mm to 1200 mm.

[0108] As an example, the output end of the synthesis gas injection mechanism 7 is connected to the lower cross-section of the tower body 601. The synthesis gas injection mechanism 7 includes 1 to 8 sections of pipelines that are interconnected. The diameters of the multiple sections of pipelines gradually increase from the input end to the output end, and the diameter of the pipeline adjacent to the lower cross-section of the tower body 601 is consistent with the diameter of the lower cross-section of the tower body 601.

[0109] Specifically, the synthesis gas injection mechanism 7 includes 1 to 8 sections (such as 1, 2, 4, 6, 8, or any other number) of pipelines that are interconnected.

[0110] See Figure 2 The input end of the syngas injection mechanism 7 is connected to the fire-tube boiler 2 via a curved pipe, and the output end is connected to the bottom end of the tower body 601. This is configured as a pipeline with a gradually expanding diameter. This aims to reduce the velocity of the syngas, keeping it at a velocity of 2-10 m / s upon entering the tower body 601. This promotes uniform distribution within the tower body 601, reduces impact on the internal components of the tower body 601, and increases its residence time. To avoid problems such as a large difference in diameter before and after expansion, uneven gas distribution, biased flow, and backflow caused by a single expansion, the syngas injection mechanism 7 preferably undergoes 2-4 stages of gradual expansion.

[0111] As an example, the synthesis gas injection mechanism 7 includes multiple synthesis gas injection pipes 701, which are located in the same plane and are all arranged tangentially to the tower body 601. The input ends of the multiple synthesis gas injection pipes 701 are respectively connected to the output ends of the fire tube boiler 2. The synthesis gas enters the tower body 601 tangentially along the multiple synthesis gas injection pipes 701 and forms a rotating flow.

[0112] See Figure 3 and see Figure 4 In a specific embodiment of the present invention, the synthesis gas injection mechanism 7 includes four synthesis gas injection pipes 701. Each synthesis gas injection pipe 701 is arranged along the tangent direction of the tower body 601 and is located on the same plane. The four synthesis gas injection pipes 701 are evenly distributed around the circumference of the tower body 601, and the output ends are all connected to the tower body 601. The synthesis gas enters the tower body 601 tangentially from the bottom to form a rotating flow. Preferably, the synthesis gas injection pipe 701 is 500 mm to 800 mm away from the lower tangent line of the tower body 601.

[0113] The raw materials used for the gasified synthesis gas in the present invention can be coal, petroleum coke, biomass, municipal waste, and waste liquid. The existing gasification full-waste boiler process is adopted. The upper part of the gasifier 1 realizes raw material gasification, the lower part realizes radiation heat recovery, and then the fire tube boiler 2 realizes convection heat recovery. Finally, the fly ash filter 8 realizes the separation of synthesis gas and fly ash. The method of coupled enhanced dechlorination of gasified synthesis gas in the present invention is to insert a dechlorination device between the fire tube boiler 2 and the fly ash filter 8 of the gasification full-waste boiler process.

[0114] The present invention adopts the above system to carry out a method for coupled enhanced dechlorination of gasification synthesis gas, comprising the following steps:

[0115] S1. The high-temperature syngas generated in the gasifier 1 enters the fire tube boiler 2, which cools the high-temperature syngas. The cooled syngas is then injected into the tower body 601 through the syngas injection mechanism 7 to obtain pre-dechlorinated syngas.

[0116] S2. Add the dechlorinating agent to the atmospheric pressure bin 302 of the dechlorinating agent feeding unit. Pressurize the lock hopper 303 to allow the dechlorinating agent in the atmospheric pressure bin 302 to enter the feeding tank 304. The dechlorinating agent in the feeding tank 304 enters the tower body 601 through the injection pipe 4 under the action of pressure. At the same time, the carrier gas pipeline 5 is opened, and the carrier gas carrying the dechlorinating agent is injected into the tower body 601 through the injection pipe 4 at a certain flow rate.

[0117] S3: After the dechlorination agent injected into the tower body 601 is preliminarily mixed with the pre-dechlorinated synthesis gas, it is fully and evenly distributed through the orifice plate uniform distribution structure 6011, and then enters the cyclone mixing structure to fully dechlorinate the synthesis gas;

[0118] S4: The dechlorinated synthesis gas is transported to the fly ash filter 8, where fly ash, dechlorinating agent, or reaction products are separated to obtain dechlorinated synthesis gas. As an example, in step S2, the synthesis gas is injected into the tower body 601 via the synthesis gas injection mechanism 7 at a velocity of 2 to 10 m / s.

[0119] Specifically, the gas velocity of the synthesis gas injected into the tower body 601 through the synthesis gas injection mechanism 7 may include values ​​within any range such as 2 m / s, 4 m / s, 6 m / s, 8 m / s, and 10 m / s.

[0120] As an example, the mesh size of the dechlorination agent in step S2 is 32 mesh to 1000 mesh.

[0121] Specifically, the mesh size of the dechlorinating agent may include values ​​within any range such as 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 (such as 200 mesh, 300 mesh, 400 mesh, 500 mesh, etc.); fine particles of the dechlorinating agent can increase the specific surface area and improve the reaction rate and efficiency of the dechlorinating agent and synthesis gas.

[0122] In a specific embodiment of the present invention, 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.

[0123] As an example, the carrier gas carrying the dechlorination agent is injected into the tower body 601 at a gas velocity of 2 to 15 m / s.

[0124] Specifically, the gas velocity of the carrier gas carrying the dechlorination agent and injected into the tower body 601 may include values ​​within any range such as 2 m / s, 3 m / s, 5 m / s, 10 m / s, 12 m / s, and 15 m / s.

[0125] In order to better understand the system and method for coupled enhanced dechlorination of gasification and synthesis gas in the present invention, the system and method for coupled enhanced dechlorination of gasification and synthesis gas in the present invention are described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0126] Example 1

[0127] See Figure 1 and Figure 2 This embodiment provides a system for gasification and synthesis gas coupled with enhanced dechlorination, comprising a gasifier 1, a fire tube boiler 2, a dechlorination device, a synthesis gas 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 synthesis gas. The input end of the fire tube boiler 2 is connected to the gasifier 1, and the high-temperature synthesis gas enters the fire tube boiler 2 for heat recovery and cooling. The dechlorination device includes a dechlorination agent feeding unit and a dechlorination tower 6 (see Figure 2); a dechlorinating agent feeding unit is used to provide a dechlorinating agent; the dechlorinating tower 6 includes a tower body 601 (the diameter of the tower body 601 is 1400 mm, and the height of the tower body 601 is 14 m), 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 sprays the dechlorinating agent into the tower body 601 through the injection pipe 4; the tower body 601 is also provided with an orifice plate uniformly distributed structure 6011 and a swirl mixing structure, the orifice plate uniformly distributed structure 6011 is located above the injection pipe 4, and the swirl mixing structure is located at the orifice plate uniformly distributed structure 6011 Above; the input end of the synthesis gas injection mechanism 7 is connected to the output end of the fire tube boiler 2, and the output end of the synthesis gas injection mechanism 7 is connected to the bottom of the tower body 601 and is located below the injection pipe 4. The cooled synthesis gas is injected into the tower body 601 through the synthesis gas injection mechanism 7, and the gas-solid mixture formed by the synthesis gas and the dechlorination agent is fully and evenly distributed through the orifice plate uniform distribution structure 6011, and then enters the cyclone mixing structure for full mixing reaction; the fly ash filter 8 is connected to the output end of the dechlorination tower 6 through a pipeline, and the dechlorinated synthesis gas enters the fly ash filter 8, and the fly ash filter 8 is used to separate the fly ash in the synthesis gas.

[0128] In this embodiment, the dechlorination feeding unit includes a bag dust collector 301, a normal pressure bin 302, a lock hopper 303 and a feeding tank 304, which are connected in sequence from top to bottom by pipes; the normal pressure bin 302 is used to load the dechlorination agent, and the lock hopper 303 is used to control the pressurized delivery of the dechlorination agent. The lock hopper 303 is pressurized to allow the dechlorination agent in the normal pressure bin 302 to enter the feeding tank 304, and the depressurized gas from the lock hopper 303 enters the bag dust collector 301. The dechlorination agent filtered by the bag dust collector 301 enters the normal pressure bin 302 through a rotary valve. The feeding tank 304 is connected to the tower body 601 through the injection pipe 4, and the dechlorination agent in the feeding tank 304 is sprayed into the tower body 601 through the injection pipe 4 under pressure.

[0129] In this embodiment, the diameter of the injection pipe 4 is 15 mm, the injection pipe 4 is arranged perpendicular to the tower body 601, the distance between the injection pipe 4 and the lower tangent of the tower body 601 is 1000 mm, and the input end of the injection pipe 4 is also connected to the carrier gas pipeline 5, which is used to provide carrier gas, and the carrier gas carries the dechlorination agent and is sprayed into the tower body 601; and the output end of the injection pipe 4 is arranged at the center position of the inner cavity of the tower body 601, and the output end of the injection pipe 4 is curved downward, and the dechlorination agent is sprayed downward from the output end of the injection pipe 4.

[0130] In this embodiment, the orifice plate uniform distribution structure 6011 is horizontally arranged on the inner wall of the tower body 601, and the distance between the orifice plate uniform distribution structure 6011 and the horizontal position of the injection pipe 4 is 500 mm. The orifice plate uniform distribution structure 6011 is disc-shaped and has multiple sieve holes 60111 evenly opened. The diameter of the sieve hole 60111 is 20 mm, and the center distance between two adjacent sieve holes 60111 is 2.5 times the diameter of the sieve hole 60111. The outlet of the sieve hole 60111 is provided with a chamfer α, and the angle of the chamfer α is 40°, so as to realize the diffusion of part of the air flow after passing through the hole to the surrounding area.

[0131] In this embodiment, 36 openings 60112 are provided on the outer edge of the hole plate uniform distribution structure 6011 . The 36 openings 60112 are equidistantly arranged along the outer edge of the hole plate uniform distribution structure 6011 , and the diameter of the openings 60112 is 20 mm.

[0132] In this embodiment, the swirl mixing structure includes four swirl plates, the spacing between the four swirl plates is 3000 mm, and the four swirl plates are alternately arranged in positive and negative directions along the axial direction of the tower body 601, and the distance between the bottom swirl plate and the upper surface of the Venturi structure 6012 is 800 mm.

[0133] In this embodiment, the swirl plate includes a central disk 60131 and two fixed rings 60132. The inner diameter of the central disk 60131 is 60 mm, and the thickness of the fixed rings 60132 is 28 mm. The central disk 60131 and the two fixed rings 60132 are arranged concentrically. 30 blades 60133 are evenly distributed on the circumference between the central disk 60131 and the adjacent fixed rings 60132. 60 blades 60133 are also evenly installed on the circumference between two adjacent fixed rings 60132. The thickness of the blades 60133 is 2 mm, the inclination angle of the blades 60133 is 25°, the radial angle of the blades 60133 is 16.6°, and each blade 60133 is installed at the same oblique angle.

[0134] In this embodiment, a Venturi structure 6012 is further provided between the orifice plate uniform distribution structure 6011 and the swirl mixing structure. The variable diameter of the Venturi structure 6012 is 650 mm, and the distance between the lower end face of the Venturi structure 6012 and the horizontal position of the injection pipe 4 is 1000 mm. The Venturi structure 6012 is used to increase the back mixing of the gas-solid mixture.

[0135] In this embodiment, see Figure 2 The output end of the synthesis gas injection mechanism 7 is connected to the lower section of the tower body 601. The synthesis gas injection mechanism 7 includes two sections of pipelines that are connected to each other. The diameters of the two sections of pipelines gradually increase from the input end to the output end. The diameter of the pipeline adjacent to the lower section of the tower body 601 is consistent with the diameter of the lower section of the tower body 601.

[0136] This embodiment also provides a method for coupled enhanced dechlorination of gasified syngas, which is performed using the system of this embodiment and specifically includes the following steps:

[0137] S1: The high-temperature syngas generated in the gasifier 1 enters the fire-tube boiler 2, which recovers heat and cools the high-temperature syngas. The cooled syngas is then injected into the tower 601 through the syngas injection mechanism 7 at a velocity of 2.8 m / s to obtain pre-dechlorinated syngas.

[0138] S2. Add a 300-mesh calcium oxide dechlorinating agent into the atmospheric pressure bin 302 of the dechlorinating agent feeding unit. Pressurize the lock hopper 303 to allow the dechlorinating agent in the atmospheric pressure bin 302 to enter the feeding tank 304. The dechlorinating agent in the feeding tank 304 enters the tower body 601 through the injection pipe 4 under pressure. At the same time, open the carrier gas line 5. The carrier gas carrying the dechlorinating agent is injected into the tower body 601 through the injection pipe 4 at a flow rate of 6 m / s. The volume flow ratio of the carrier gas to the pre-dechlorinated synthesis gas is 1:300.

[0139] S3, after the dechlorination agent and the pre-dechlorinated synthesis gas are initially mixed, they are fully and evenly distributed through the orifice plate uniform distribution structure 6011, and then enter the cyclone mixing structure to fully dechlorinate the synthesis gas. The average residence time of the gas is about 8 seconds;

[0140] S4. The dechlorinated synthesis gas is transported to the fly ash filter 8, where fly ash, dechlorinating agent or reaction products are separated to obtain dechlorinated synthesis gas.

[0141] Example 2

[0142] See Figure 1 and Figure 3 This embodiment provides a system for gasification and synthesis gas coupled with enhanced dechlorination. The difference between this system and embodiment 1 is that: in this embodiment, the distance between the injection pipe 4 and the lower tangent line of the tower body 601 is 2000 mm; in this embodiment, the synthesis gas injection mechanism 7 includes four synthesis gas injection pipes 701 (see Figure 4 ), the four synthesis gas injection pipes 701 are located in the same plane and are all arranged tangentially to the tower body 601. The input ends of the four synthesis gas injection pipes 701 are respectively connected to the output ends of the fire tube boiler 2. The synthesis gas enters the tower body 601 tangentially along the four synthesis gas injection pipes 701 and forms a rotating flow. The distance between the four synthesis gas injection pipes 701 and the lower tangent line of the tower body 601 is 800 mm; the other structures are the same as those in Example 1 and are not repeated here.

[0143] This embodiment also provides a method for coupled enhanced dechlorination of gasified synthesis gas, which is performed using the system in this embodiment and is the same as that in Example 1, and will not be described in detail here.

[0144] In summary, the present invention provides a kind of efficient, environmentally friendly and economical dechlorination method and device, on the basis of not changing 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 simple, and the chloride ions in the gasification synthesis gas can be effectively removed; at the same time, the original fly ash filter has an interception effect on the dry powder dechlorination agent and fly ash, and there is no need to add additional separation equipment. It can also effectively solve the problems of equipment corrosion and salt accumulation, reduce the consumption and cost of the dechlorination agent, reduce the discharge of chlorine-containing wastewater, meet the dechlorination requirements of high-chlorine content biomass raw materials, thereby protecting subsequent equipment and stabilizing system operation. The present invention adopts carrier gas to inject the dechlorination agent into the dechlorination tower in a countercurrent manner, realizes the countercurrent injection of the dry powder dechlorination agent and mixes with a large amount of synthesis gas, increases disturbance, increases the uniformity and sufficiency of the contact between the dechlorination agent and the synthesis gas, and significantly improves the dechlorination effect; the multiple pipelines of the synthesis gas injection mechanism are expanded section by section to reduce the gas velocity of the synthesis gas entering the tower body, to strengthen the uniform distribution of the synthesis gas in the tower body, reduce the impact on the tower body, increase the residence time in the tower body, and further improve the dechlorination efficiency. In addition, the unique structural design of the dechlorination tower significantly reduces the dead zone of accumulated solids, further enhancing the mixing and reaction efficiency of the synthesis gas and the dechlorinating agent, and reducing the excess ratio and total consumption of the dechlorinating agent. The uniformly distributed perforated plate structure ensures sufficient uniform distribution and mixing of the synthesis gas and the dry powder dechlorinating agent. The alternating forward and reverse swirl mixing structure increases airflow disturbance, making it difficult for fly ash to accumulate and adhere. It also increases the contact area between the synthesis gas and the dechlorinating agent, prolonging the residence time and thus the reaction time, thereby improving the dechlorination efficiency. The Venturi structure causes a certain degree of back-mixing of the dry powder dechlorinating agent and the synthesis gas, making the particles more dispersed and further enhancing the mixing effect. Therefore, the present invention effectively overcomes various shortcomings of the prior art and has high industrial application value.

[0145] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

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

2. The system for gasification synthesis gas coupled with enhanced dechlorination according to claim 1, characterized in that: The dechlorination feeding unit includes a normal pressure bin, a lock hopper and a feeding tank which are connected in sequence from top to bottom through pipelines; the normal pressure bin is used to load the dechlorination agent, the lock hopper is used to control the pressurized delivery of the dechlorination agent, the lock hopper pressurizes the dechlorination agent in the normal pressure bin to enter the feeding tank, the feeding tank is connected to the tower body through the injection pipeline, and the dechlorination agent in the feeding tank is sprayed into the tower body through the injection pipeline under pressure.

3. The system for gasification synthesis gas coupled with enhanced dechlorination 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 dechlorination agent and is injected into the tower body. The output end of the injection pipe is arranged in the inner cavity of the tower body. The output end of the injection pipe is bent downward, and the dechlorination agent is injected downward from the output end of the injection pipe.

4. The system for gasification synthesis gas coupled with enhanced dechlorination according to claim 1, characterized in that: The orifice plate uniform distribution structure is horizontally arranged on the inner wall of the tower body. The orifice plate uniform distribution structure is disc-shaped and has multiple sieve holes evenly opened. The outlets of the sieve holes are all chamfered, and the angle of the chamfer is 30° to 75°, so as to realize the diffusion of part of the airflow after passing through the hole to the surrounding area.

5. The system for gasification synthesis gas coupled with enhanced dechlorination according to claim 4, characterized in that: A plurality of openings are provided on the outer edge of the orifice plate uniform distribution structure, and the plurality of openings are equidistantly arranged along the outer edge of the orifice plate uniform distribution structure to prevent solid accumulation between the inner wall of the tower body and the orifice plate uniform distribution structure.

6. The system for gasification synthesis gas coupled with enhanced dechlorination according to claim 1, characterized in that: The swirl mixing structure includes a plurality of swirl plates, which are equidistantly installed in the tower body and are alternately arranged in forward and reverse directions along the axial direction of the tower body.

7. The system for gasification synthesis gas coupled with enhanced dechlorination 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 on the circumference between the central disk and the adjacent fixed rings. Multiple blades are also evenly installed on the circumference between two adjacent fixed rings, and each blade is installed at the same oblique angle.

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

9. The system for gasification synthesis gas coupled with enhanced dechlorination according to claim 1, characterized in that: The output end of the synthesis gas injection mechanism is connected to the lower section of the tower body. The synthesis gas injection mechanism includes 1 to 8 sections of interconnected pipelines. The diameters of the multiple sections of the pipelines gradually increase from the input end to the output end, and the diameter of the pipeline adjacent to the lower section of the tower body is consistent with the diameter of the lower section of the tower body.

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

11. A method for coupled enhanced dechlorination of gasification synthesis gas using the system according to any one of claims 1 to 10, characterized in that: The following steps are involved: The high-temperature synthesis gas generated in the gasifier enters the fire tube boiler, which recovers heat and cools the high-temperature synthesis gas. The cooled synthesis gas is then injected into the tower body through the synthesis gas injection mechanism to obtain pre-dechlorinated synthesis gas. The dechlorinating agent is added to the atmospheric pressure bin of the dechlorinating agent feeding unit, and the lock hopper is pressurized to allow the dechlorinating agent in the atmospheric pressure bin to enter the feeding tank. The dechlorinating agent in the feeding tank enters the tower body through the injection pipe under the action of pressure. At the same time, the carrier gas pipeline is opened, and the carrier gas carrying the dechlorinating agent is injected into the tower body through the injection pipe at a certain flow rate; After the dechlorination agent injected into the tower body is preliminarily mixed with the pre-dechlorinated synthesis gas, it is fully and evenly distributed through the orifice plate uniform distribution structure, and then enters the cyclone mixing structure to fully dechlorinate the synthesis gas; The dechlorinated synthesis gas is transported to the fly ash filter, and fly ash, dechlorinating agent or reaction product are separated by the fly ash filter to obtain dechlorinated synthesis gas.

12. The method for coupled enhanced dechlorination of gasified synthesis gas according to claim 11, characterized in that: Includes one or a combination of the following conditions: The synthesis gas is injected into the tower body through the synthesis gas injection mechanism at a gas velocity of 2 to 10 m / s; The mesh number of the dechlorination agent is 32 mesh to 1000 mesh; The carrier gas carrying the dechlorination agent is sprayed into the tower body at a gas velocity of 2 to 15 m / s.

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