A molten metal-based gasification method

Abstract

The present application relates to a kind of gasification methods based on molten metal, belong to the recycling technology field based on recyclable, renewable resources such as domestic waste, industrial waste and biomass, solve the problem that macromolecular organic matter is not completely decomposed in prior art, leading to the problem that same quality or high quality utilization cannot be realized, and the problem of secondary pollution to environment etc..A kind of gasification methods based on molten metal, with molten metal as medium and heat source, material containing high molecular compound is decomposed and gasification reaction under the action of gasification agent, generates inorganic mixed gas, including CO and H2.Realize the same quality and high quality recycling of recyclable, renewable resources such as domestic waste, industrial waste and biomass.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of recycling of recyclable and renewable resources such as household garbage, industrial garbage and biomass, and particularly relates to a gasification method based on molten metal. BACKGROUND

[0002] Under the background of global carbon reduction, three fields are recognized as difficult to get rid of the dependence on carbon, which are aviation and shipping industry, ocean transportation industry and plastic production industry. Through the recycling of recyclable resources, the recycling of renewable resources and the conversion utilization of carbon dioxide, the dependence on one-time petrochemical energy can be reduced to a certain extent. However, due to the high stability and high capture cost of carbon dioxide, its direct conversion utilization faces great challenges. Therefore, the recycling of recyclable resources and the recycling of renewable resources become more realistic and preferred choices.

[0003] At present, the resource and energy utilization technology of biomass (a renewable resource) and low-quality waste plastic (a recyclable resource) mainly adopts thermal disposal technology, which is divided into direct incineration and pyrolysis gasification. Since direct incineration is a solid heterogeneous combustion, there are problems of incomplete combustion, low efficiency, secondary pollution caused by incomplete combustion, especially the emission of dioxin, which restricts the wide application of this technology. Pyrolysis gasification can convert municipal solid waste into three types of products, i.e. gas, liquid and solid, which can be used to effectively improve the utilization efficiency, utilization range and economy. From the perspective of pollutant emission, the pyrolysis gasification process is carried out in a poor oxygen or oxygen-free atmosphere, which reduces the generation of dioxin in principle, and most of the heavy metals dissolve into the ash during the pyrolysis gasification process, reducing the emission amount. Therefore, developing pyrolysis gasification technology is an important way to realize the harmless, resource and energy utilization of municipal solid waste.

[0004] Pyrolysis gasification technology is a technology that converts large molecular organic matter into small molecular fuel gas, tar and coke under the condition of no oxygen or lack of oxygen by using heat to make the components undergo bond breaking, isomerization and small molecule polymerization reactions. Existing pyrolysis gasification technologies such as Landgard system using rotary kiln pyrolysis, CAO system using grate incineration technology, Purox system using internal heat type moving bed, etc. have the problems of complex target product composition, poor quality, high subsequent recycling cost, and inability to realize high-quality utilization, etc. The flue gas in the gasification process may contain nitrogen oxides, dioxin, heavy metals and other harmful substances, causing secondary pollution to the environment, and the process is complex, the construction and operation cost is high. SUMMARY

[0005] In view of the above analysis, the embodiments of the present application aim to provide a molten metal-based gasification method to solve at least one of the problems that the existing pyrolysis gasification technology cannot realize the reuse of the same quality or even high quality, and the process is complex and causes secondary pollution to the environment.

[0006] In one aspect, the embodiments of the present application provide a molten metal-based gasification method, which uses molten metal as a medium and heat source, and decomposes and gasifies a material containing a high molecular compound under the action of a gasification agent to generate inorganic mixed gas including CO and H2.

[0007] Further, the molten metal is iron liquid or copper liquid.

[0008] Specifically, the gasification agent is one or a mixture of both of oxygen and superheated steam.

[0009] Illustratively, the gasification agent is sprayed into the molten metal by a lance.

[0010] Preferably, the spraying speed of the gasification agent is 200-250 m / s.

[0011] It should be noted that the material containing a high molecular compound includes one or more of household garbage, industrial garbage, and biomass.

[0012] Further, the material is biomass, which is treated into a powder state before the decomposition and gasification reaction, and is sprayed into the molten metal by a lance to perform the decomposition and gasification reaction under the action of the molten metal and the gasification agent, and the spraying speed of the biomass powder is 200-250 m / s.

[0013] Specifically, the material includes household garbage and / or industrial garbage, and the decomposition and gasification reaction includes a primary gasification reaction and a secondary gasification reaction; after the primary gasification reaction of the material under the action of the molten metal and the gasification agent, the generated first mixed gas is introduced into the bottom of the molten metal and passes through the molten metal layer upwards to perform the secondary gasification reaction under the action of the molten metal and the gasification agent, and generates inorganic mixed gas including CO and H2.

[0014] Further, the inorganic mixed gas passes through a slag liquid layer upwards to perform filtration.

[0015] Preferably, the industrial garbage includes a circuit board, the molten metal is copper liquid, and the decomposition and gasification reaction includes a primary gasification reaction and a secondary gasification reaction; after the primary gasification reaction of the circuit board under the action of the copper liquid and the gasification agent, the generated first mixed gas is introduced into the bottom of the copper liquid and passes through the copper liquid layer upwards to perform the secondary gasification reaction under the action of the copper liquid and the gasification agent, and generates inorganic mixed gas; at the same time of the primary gasification reaction, the copper in the circuit board enters the copper liquid.

[0016] In another aspect, the embodiment of the present application also provides a molten metal-based gasification system for realizing the gasification method, comprising a feeding and preheating system, a gasification agent supply system, a molten metal reaction system connected in sequence through a pipeline, a synthetic gas purification and heat exchange system, and a synthetic gas storage system; the feeding and preheating system is connected with the inlet of the molten metal reaction system through a sealing interface; the gasification agent supply system comprises a superheated steam boiler and / or an oxygen tank, the outlets of which are connected with gasification agent lances respectively into the molten metal reaction system.

[0017] Compared with the prior art, the present application can realize at least one of the following beneficial effects:

[0018] 1. The present application uses molten metal as a medium and gasification agent to decompose high molecular compounds, and completely decomposes renewable and recyclable materials containing high molecular compounds into inorganic mixed gas, including CO, H2, CO2, and a small amount of escaped inorganic gases such as HCl and HBr. The mixed gas after purification is: synthetic gas (CO+H2) with a volume fraction of more than 90%, and the balance is CO2. The purified mixed gas can enter the subsequent processing stage, for example, to produce green methanol, sustainable aviation fuel (SAF), and high-quality green plastic and other environmentally friendly products, which helps to gradually reduce the dependence on disposable petrochemical resources.

[0019] 2. When the decomposition gasification reaction uses iron liquid (1400℃-1700℃) as a heat source and medium, the iron liquid has strong heat storage capacity and can quickly transfer heat, providing high temperature while acting as a catalyst to quickly decompose difficult-to-handle high molecular compounds into small molecules. The metal iron acts as a catalyst, optimizes the reaction path through a two-step reaction mechanism, and makes the catalytic process generate more CO than CO2, thereby effectively reducing the emission of greenhouse gases. The iron liquid not only improves the overall efficiency of the reaction during the entire reaction process, but also reduces the energy consumption of the reaction through its catalytic effect, while achieving environmental friendliness.

[0020] In particular, the molten metal-based gasification method of the present application uses copper liquid as a heat source and medium when processing industrial waste containing copper circuit boards, which completely decomposes the materials into inorganic substances while the metal copper in the circuit board directly enters the copper liquid, which is conducive to the recovery of copper in the circuit board.

[0021] 3. The decomposition gasification reaction of the present application uses metal as a heat source, which can be heated by electromagnetic vortex method to maintain the heat of the metal pool, with low energy consumption.

[0022] 4. The application is aimed at all kinds of household garbage and / or industrial garbage containing high molecular polymers, especially high molecular polymers containing bromide, and a two-stage gasification reaction based on molten metal is designed, the above-mentioned materials first undergo a primary gasification reaction under the action of molten metal and gasification agent, generating a first mixed gas containing organic matter from methane to C40, the first mixed gas passes through molten metal again and undergoes a secondary gasification reaction with the action of gasification agent, and is completely decomposed into inorganic mixed gas; the inorganic mixed gas further passes through a slag liquid layer, and ash, sulfur, chlorides and the like are captured into the slag liquid, so that the gas is more pure, and coking and the like problems will not occur at the rear end.

[0023] 5. The application designs a gasification system including a feeding and preheating system and a molten metal reaction kettle for realizing a decomposition gasification reaction based on molten metal; two-stage molten metal reaction kettles connected with each other through a gas-liquid channel are adopted to decompose and gasify the materials containing high molecular polymers, the crude gas (gasification gas containing organic components) generated by the primary molten metal reaction kettle is sprayed into the bottom layer of the secondary molten metal reaction kettle through the gas-liquid channel, and the crude gas is further decomposed by the high-temperature iron liquid layer and the high-temperature slag liquid layer of the secondary molten metal reaction kettle to be completely gasified into inorganic mixed gas, so as to ensure that no high molecules escape.

[0024] In the application, the above technical solutions can be combined with each other to realize more preferred combination solutions. Other features and advantages of the application will be described in the subsequent specification, and some advantages will become apparent from the specification or be understood by implementing the application. The purposes and other advantages of the application can be realized and obtained from the contents particularly pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0026] Figure 1 Working state diagram of the molten metal reaction kettle of the application after adding iron liquid and slag liquid;

[0027] Figure 2 Appearance diagram of the molten metal reaction kettle of the application;

[0028] Figure 3 Sectional view diagram of the molten metal reaction kettle of the application;

[0029] Figure 4 Feeding and preheating system diagram of the application;

[0030] Figure 5 External heat exchange system diagram of the feeding tank of the application;

[0031] Figure 6Fig. 1 is a perspective view of the present invention; Figure 5 Fig. 2 is a partial enlarged view of A in the present invention;

[0032] Figure 7 Fig. 3 is a longitudinal sectional view of the loading tank of the present invention;

[0033] Figure 8 Fig. 4 is a front view of the rotating shaft and the paddles of the present invention;

[0034] Figure 9 Fig. 5 is a top view of the inner side paddle unit and the rotating shaft of the present invention;

[0035] Figure 10 Fig. 6 is a front view of the first paddle of the present invention;

[0036] Figure 11 Fig. 7 is a top view of the upper outer side paddle and the rotating shaft in the upper region of the rotating shaft of the present invention;

[0037] Figure 12 Fig. 8 is a top view of the lower outer side paddle and the rotating shaft in the lower region of the rotating shaft of the present invention;

[0038] Figure 13 Fig. 9 is a top view of the upper segment paddle and the rotating shaft in the conical discharge opening region of the present invention;

[0039] Figure 14 Fig. 10 is a top view of the shovel paddle and the rotating shaft of the present invention;

[0040] Figure 15 Fig. 11 is a top view of the discharge opening flange of the present invention;

[0041] Figure 16 Fig. 12 is a perspective view of the conical discharge opening, the discharge opening flange and the shovel paddle of the present invention;

[0042] Figure 17 Fig. 13 is a schematic diagram of the angle relationship of the inner side paddle unit in the top view of the present invention; Figure 1 ;

[0043] Figure 18 Fig. 14 is a schematic diagram of the angle relationship of the inner side paddle unit in the top view of the present invention; Figure 2 ;

[0044] Figure 19 Fig. 15 is a schematic diagram of the angle relationship of the inner side paddle unit in the front view of the embodiment 5 of the present invention;

[0045] Figure 20 Fig. 16 is a schematic diagram of the angle relationship of the upper outer side paddle unit in the top view of the embodiment 5 of the present invention;

[0046] Figure 21 Fig. 17 is a schematic diagram of the angle relationship of the lower outer side paddle unit in the top view of the embodiment 5 of the present invention;

[0047] Figure 22Figure 1 is a schematic diagram of the angle relationship of the front view perspective outer side of the material pushing piece unit of the embodiment 5 of the present application.

[0048] Figure 23 Figure 2 is a diagram of the gasification system based on molten metal of the embodiment 2 of the present application.

[0049] Reference signs:

[0050] 1 - primary molten metal reactor; 101 - first metal pool; 102 - feeding port; 2 - secondary molten metal reactor; 201 - second metal pool; 202 - slag pool; 3 - gas-liquid passage; 4 - liquid discharge port; 501 - upper slag discharge port; 502 - middle slag discharge port; 503 - lower slag discharge port; 601 - first gasification agent spray gun mounting port; 602 - second gasification agent spray gun mounting port; 7 - third gasification agent spray gun mounting port; 8 - biomass spray gun mounting port; 9 - synthetic gas outlet; 10 - second screw conveyor; 11 - molten channel; 12 - third gasification agent spray gun; 13 - biomass spray gun; 14 - first gasification agent spray gun; 15 - second gasification agent spray gun; 16 - pouring tank A; 17 - pouring tank B; 18 - first screw conveyor; 19 - feeding tank; 20 - second screw conveyor; 21 - tank body; 22 - flange of pouring port; 23 - heat exchange jacket; 24 - medium inlet; 25 - medium outlet; 26 - fin; 27 - conical pouring port; 28 - necked flange; 29 - rotating shaft; 30 - inner side material pushing piece unit; 31 - outer side upper material pushing piece; 32 - outer side lower material pushing piece; 33 - lower end bearing; 34 - upper end bearing; 35 - second paddle; 36 - first transmission shaft; 37 - third paddle; 38 - first paddle; 39 - second transmission shaft; O1 - center of the cross section of the rotating shaft; O2 - center of the circle where the outer arc of the first paddle is located; a - central angle of the first paddle. DETAILED DESCRIPTION

[0051] The preferred embodiments of the present application will be described in detail below with reference to the drawings, which form a part of this application. The drawings and the associated description are used to explain the principles of the present application and are not intended to limit the scope of the present application.

[0052] In one aspect, the embodiment of the present application provides a gasification method based on molten metal, which uses molten metal as medium and heat source, and decomposes and gasifies the material containing high molecular compound under the action of gasification agent to generate inorganic mixed gas containing CO and H2.

[0053] It should be noted that the molten metal can be molten iron, and the temperature is 1400-1700℃. On the one hand, the metal iron is used as a reaction heat source, and the melting temperature range is 1400-1700℃, which is suitable for the demand temperature range of the decomposition gasification reaction. On the other hand, the metal iron is used as a catalyst. First, in the first step of the reaction, the molten iron reacts with carbon, oxygen and water in the material respectively to generate Fe3C and FeO, and H2 and CO are generated at the same time. In this process, the molten iron not only promotes the conversion of carbon, but also significantly reduces the activation energy of the oxygen reduction reaction, accelerates the reduction process of oxygen, and also reduces the reaction activation energy of water pyrolysis, thereby greatly improving the overall reaction efficiency. In the second step of the reaction, liquid Fe3C and FeO further react to generate metal iron and CO. Through this two-step reaction mechanism, the molten iron optimizes the reaction path, so that the catalytic process generates more CO than CO2, thereby effectively reducing the emission of greenhouse gases. The molten iron not only improves the overall efficiency of the reaction during the entire reaction process, but also reduces the energy consumption of the reaction through its catalytic effect, and at the same time realizes environmental friendliness.

[0054] The material reacts rapidly under the action of the molten iron and the gasification agent, and the theoretical reaction time is within 0.1 seconds. Based on the high reaction rate, the gasification agent can be stopped within 2-3 minutes after stopping the feeding. Since there is a large amount of carbon-containing substance in the molten iron, the gasification agent needs to be continued after the feeding is stopped.

[0055] It should be noted that theoretically, the molten iron is not lost during the reaction process. However, in actual operation, the molten iron will be partially lost with the slag liquid. For example, in the process of gasifying per ton of biomass, the loss of molten iron is not more than 1 kg. In order to compensate for this loss, iron ore is added to the molten metal together with the material during the reaction process to supplement the molten iron.

[0056] Preferably, the molten metal can be molten copper, and the temperature is 1000-1300℃. When the material containing high molecular compounds is a circuit board, the molten copper is used as a medium and a heat source to realize the complete decomposition and gasification of the material into synthesis gas, and the copper in the circuit board directly enters the molten copper, which is beneficial to the recovery of copper in the circuit board.

[0057] It should be noted that the gasification agent is one or a mixture of two of oxygen and superheated steam.

[0058] System heat balance: when all using oxygen as gasifying agent, the high molecular chain breaking reaction in the material is endothermic reaction, and the incomplete oxidation reaction involving oxygen can release a large amount of heat, so the heat generated by the gasification reaction itself can maintain the temperature required by the reaction, without external heating, so as to keep the system heat balance; when all using water vapor as gasifying agent, the high molecular chain breaking reaction in the material is endothermic reaction, and the reaction of water vapor decomposing into H2 and CO at high temperature is also endothermic reaction, so external heating is needed to maintain the system heat balance; when using mixed gas of oxygen and water vapor as gasifying agent, according to the proportion of the two, the external heating condition is adjusted.

[0059] Product synthesis gas composition: when the gasifying agent is all oxygen, the oxidation degree is high, the proportion of CO generated is high, and part of CO2 is also generated; when the gasifying agent is all water vapor, the water gas reaction (C+H2O→CO+H2) is promoted, which can increase the total volume of the product synthesis gas and the proportion of H2.

[0060] In a possible design, the gasifying agent is oxygen, and the purified inorganic mixed gas includes CO, H2 and CO2, wherein the volume proportion of CO is 60%, the volume proportion of H2 is 39%, and the volume proportion of CO2 is 1%.

[0061] In a possible design, the gasifying agent is water vapor, and the purified inorganic mixed gas includes CO and H2 mixed gas, wherein the volume proportion of CO is 40%, and the volume proportion of H2 is 60%.

[0062] Preferably, the purification of the inorganic mixed gas includes dust removal, washing (such as alkali washing), etc., and the composition and component detection of the inorganic mixed gas are carried out after purification, because the temperature of the mixed gas is high after the decomposition gasification reaction is completed, and it is difficult to directly detect.

[0063] Preferably, the decomposition gasification reaction of the present application uses molten metal as heat source, which can be heated by electromagnetic vortex method, maintains system heat balance, and has low energy consumption.

[0064] Further, the gasifying agent is sprayed into the molten metal through a lance, and the gasifying agent spraying speed is 200-250 m / s.

[0065] The gasifying agent is sprayed into the molten metal through a gasifying agent lance at a speed of 200 m / s or more, which is beneficial to impact mixing of the material and the molten metal, so that the reaction can be more sufficient. When the gasifying agent is oxygen, the oxygen sprayed into the molten metal can react with the molten metal, and since there is a large amount of carbon-containing substance in the iron liquid, the gasifying agent is stopped after 2-3 min after the feeding is stopped, so that the oxygen spraying amount is appropriate, and the gasifying agent overflow or excess is avoided.

[0066] It should be noted that the material containing the high molecular compound includes one or more of domestic waste, industrial waste, and biomass. The industrial waste includes a circuit board.

[0067] Preferably, the material is biomass, and before the decomposition gasification reaction, the biomass is treated into a powder state, sprayed into the molten metal through a spray gun, and subjected to the decomposition gasification reaction under the action of the molten metal and the gasification agent. The spraying speed of the biomass powder is 200-250 m / s.

[0068] Specifically, after the biomass is subjected to waste heat carbonization, it is ground into biomass powder, and then directly sprayed into the bottom of the molten metal iron liquid through a spray gun. After the collision of the biomass gas flow and the gasification agent gas flow, the iron liquid forms a boiling state. Under the high-energy and high-heat reaction environment provided by the high-temperature iron liquid and the catalysis of the metal, the biomass and the gasification agent are gasified into inorganic mixed gas.

[0069] Since the biomass itself has small particles and does not contain large high molecular substances after the carbonization treatment, it can be completely decomposed after one decomposition gasification reaction.

[0070] Further, the material includes domestic waste and / or industrial waste, and the decomposition gasification reaction includes a primary gasification reaction and a secondary gasification reaction. After the material is subjected to the primary gasification reaction under the action of the molten metal and the gasification agent, the generated first mixed gas is introduced into the bottom of the molten metal and passes through the molten metal layer upwards, subjected to the secondary gasification reaction under the action of the molten metal and the gasification agent, and generates inorganic mixed gas including CO and H2. The inorganic mixed gas passes through the slag liquid layer for displacement and filtration, and a small amount of escaped part can be treated by subsequent purification.

[0071] It is worth noting that since the domestic waste and the industrial waste contain various types of high molecular polymers containing bromide, as well as inorganic substances containing metals and non-metals, which are much larger than the biomass molecules, they cannot be directly sprayed into the bottom of the molten metal through the spray gun after pretreatment, and the specific gravity is much smaller than the metal, so that the material cannot have sufficient contact with the iron liquid and sufficient contact time. Therefore, after the primary gasification reaction, the first mixed gas contains organic substances from methane to C40, and the proportion is uncontrollable, and the secondary reaction is necessary to completely decompose the inorganic substances.

[0072] The first mixed gas passes through the molten metal layer upwards and is in full contact with the iron liquid, ensuring complete gasification into inorganic substances without large molecular gas, and inorganic mixed gas is obtained. The inorganic mixed gas continues to pass through the slag liquid layer, which not only avoids the escape of high molecules, but also captures ash, sulfur, and chlorides into the slag liquid, so that the obtained gas is more pure and does not contain organic compounds. At the same time, since the gas is pure and all inorganic substances, there is no problem of coking at the back end.

[0073] Specifically, the slag liquid layer comprises dolomite and limestone, and the ratio of the two can be 2:1.

[0074] It should be noted that the inorganic mixed gas generated by the decomposition gasification reaction only contains inorganic components and does not contain organic hydrocarbon compounds such as methane and acetylene.

[0075] In a possible design, the industrial waste includes a circuit board, the molten metal is copper liquid, and the decomposition gasification reaction includes a primary gasification reaction and a secondary gasification reaction; after the circuit board undergoes the primary gasification reaction under the action of the copper liquid and the gasification agent, the generated first mixed gas is introduced into the bottom of the copper liquid and passes through the copper liquid layer upwards to undergo the secondary gasification reaction under the action of the copper liquid and the gasification agent, so as to obtain the inorganic mixed gas; while the primary gasification reaction is performed, the copper in the circuit board enters the copper liquid.

[0076] Preferably, the material is preheated to above 400 DEG C before the primary gasification reaction, which is beneficial to maintaining the heat balance of the decomposition gasification reaction system.

[0077] Further, the purified inorganic mixed gas enters a rear-end reaction system to perform a Fischer-Tropsch synthesis to produce green methanol, green SAF aviation coal, and green high-quality plastic and other green products.

[0078] On the other hand, a specific embodiment of the present application also provides a gasification system based on molten metal, which is used to realize the gasification method, and includes a feeding and preheating system, a gasification agent supply system, a molten metal reaction system connected by pipelines in sequence, a synthesis gas purification and heat exchange system, and a synthesis gas storage system; the feeding and preheating system is connected with the inlet of the molten metal reaction system through a sealing interface; the gasification agent supply system includes a superheated steam boiler and / or an oxygen tank, and the outlets of the two are respectively connected with a gasification agent spray gun that enters the molten metal reaction system.

[0079] Further, the molten metal reaction system includes a primary molten metal reaction kettle 1 and a secondary molten metal reaction kettle 2 that are connected with each other through a gas-liquid passage 3; the primary molten metal reaction kettle 1 is internally provided with a first metal pool 101, and the secondary molten metal reaction kettle 2 is internally provided with a second metal pool 201, wherein the bottom of the second metal pool 201 is higher than the bottom of the first metal pool 101, and the primary molten metal reaction kettle 1 and the secondary molten metal reaction kettle 2 are horizontally staggered.

[0080] The difference between the secondary molten metal reactor 2 and the first molten metal reactor 1 can ensure that the first molten metal reactor 1 has sufficient reaction pool volume to maintain the gasification reaction, and the gas generated in the first molten metal reactor 1 can enter the bottom of the molten metal in the secondary molten metal reactor 2, and the secondary molten metal reactor 2 has sufficient pool height to ensure sufficient reaction, so that the macromolecular gas which does not fully contact with the iron liquid in the first molten metal reactor 1 fully contacts with the iron liquid in the secondary molten metal reactor 2, ensuring complete gasification into inorganic matter without macromolecular gas.

[0081] Preferably, the gas-liquid passage 3 is a semi-conical passage, and the axial section of the semi-conical passage is higher than the curved surface of the semi-conical passage.

[0082] Further, the semi-conical passage includes a passage inlet, a passage main body and a passage outlet, the passage inlet is communicated with the first molten metal reactor, and the passage outlet is communicated with the secondary molten metal reactor; the passage inlet and the passage outlet are both semicircular, the diameter of the passage inlet is larger than that of the passage outlet, and the center lines of the two are collinearly aligned.

[0083] Specifically, the center line of the passage inlet is away from the bottom of the first molten metal reactor, and the bottom arc of the passage outlet is attached to the bottom of the secondary molten metal reactor.

[0084] Preferably, the distance between the center line of the passage inlet and the bottom of the first molten metal reactor is determined according to the volume of the first metal pool and the liquid level of the molten metal in the first metal pool, and when the first metal pool is filled with molten metal, the top of the passage inlet is flush with the liquid level of the molten metal.

[0085] In a possible design, the volume of the first metal pool 101 is 56 cubic meters, and the distance between the upper end surface of the passage inlet and the bottom of the first metal pool 101 in the first molten metal reactor 1 is 2 meters.

[0086] The passage main body includes a first molten metal reactor side wall section and a secondary molten metal reactor side wall section, the passage inlet is formed in the side wall of the first molten metal reactor 1, and the passage outlet is formed in the side wall of the secondary molten metal reactor 2.

[0087] It should be noted that the axial section of the passage main body is semicircular, wherein the diameter of the semicircle gradually decreases from the passage inlet to the passage outlet, the straight edge of the passage main body is horizontally placed, and the circular arc edge smoothly transitions from the passage inlet to the passage outlet, forming a gradually narrowing conical path.

[0088] In a possible design, the passage inlet is a semicircle with a diameter of 1.8-2 meters, and the passage outlet is a semicircle with a diameter of 0.6-0.8 meters.

[0089] Further, the top of the primary molten metal reactor 1 is provided with a feed inlet 102, a first gasification agent lance mounting port 601 and a second gasification agent lance mounting port 602; the top of the secondary molten metal reactor 2 is provided with a synthesis gas outlet 9; the outer side wall of the secondary molten metal reactor 2 is further provided with a third gasification agent lance mounting port 7 and a biomass lance mounting port 8; the top of the second metal pool 201 of the secondary molten metal reactor 2 is provided with a slag pool 202.

[0090] Specifically, when the molten metal reactor system is running, the material falls freely through the feed inlet 102 at the top of the primary molten metal reactor 1 into the first metal pool 101 (the material falling height is 3-3.5 meters), while the gasification agent is sprayed to the material falling position through the first gasification agent lance 14 and the second gasification agent lance 15, so as to impact and mix the material with the molten metal to perform the primary gasification reaction, so that the material is fully reacted and rapidly gasified to generate the first mixed gas; the rapid and large amount generation of the first mixed gas (the reaction time is within 0.1 second) increases the internal pressure of the primary molten metal reactor 1 (the internal pressure of the reactor is 1.5-1.8 MPa), thereby increasing the pressure difference between the primary molten metal reactor 1 and the secondary molten metal reactor 2 (for example, 0.2-0.6 MPa), and under the action of the pressure difference, the first mixed gas is sprayed to the bottom of the second metal pool 201 of the secondary molten metal reactor 2 through the gas-liquid passage 3, while the gasification agent is sprayed to the second metal pool 201 through the third gasification agent lance 12 and / or the biomass powder is sprayed to the second metal pool 201 through the biomass lance 13, and the first mixed gas is subjected to secondary complete decomposition from the bottom to the top through the molten metal layer and the slag pool to obtain the inorganic mixed gas.

[0091] It should be noted that when the first mixed gas is sprayed to the bottom of the second metal pool 201 of the secondary molten metal reactor 2 from the primary molten metal reactor 1 through the gas-liquid passage 3 under the action of the pressure, the iron liquid in the first metal pool 101 is pressed to the semicircular arc bottom of the passage outlet of the inner side wall of the secondary molten metal reactor 2, but cannot be further pressed; the space of the passage inlet section is significantly larger than that of the passage outlet section, and such a design is beneficial to the accelerated flow of the gas.

[0092] The design of the highly different metal pools in communication, and the complete filling of the minimum cross-sectional area of the passage by the iron liquid, on the one hand, effectively prevents the accumulation of blocky materials and the possible plugging problem; on the other hand, ensures that the gas exchange between the two reactors before the reaction cannot be performed.

[0093] In a possible design, the volume of the first metal pool 101 is 56 cubic meters, the volume of the second metal pool 201 is 25 cubic meters, the height difference between the bottom of the second metal pool 201 and the top of the primary metal pool 101 is 2 meters, and the material processing capacity is 80-100 tons per hour.

[0094] In a possible design, the first gasification agent lance mounting port 601 and the second gasification agent lance mounting port 602 are arranged in 180° symmetry, and the included angle with the horizontal direction is 45°, and the axes of the first gasification agent lance mounting port 601 and the second gasification agent lance mounting port 602 pass through the cross-sectional center point of the first metal pool 101.

[0095] In a possible design, the third gasification agent lance mounting port 7 and the biomass lance mounting port 8 are arranged in 180° symmetry, and the included angle with the horizontal direction is 60°, and the axes of the third gasification agent lance mounting port 7 and the biomass lance mounting port 8 pass through the cross-sectional center point of the second metal pool 201.

[0096] Preferably, the primary molten metal reactor 1 further comprises a liquid outlet 4 on the outer wall of the reactor body, which is located at the bottom of the first metal pool 101 and used for discharging the molten metal in the metal pool.

[0097] Specifically, the secondary molten metal reactor 2 further comprises a lower slag outlet 503, a middle slag outlet 502 and an upper slag outlet 501 on the outer wall of the reactor body. The lower slag outlet 503, the middle slag outlet 502 and the upper slag outlet 501 correspond to the upper liquid level, the middle liquid level and the lower liquid level of the slag-liquid pool 202, respectively.

[0098] The upper slag outlet 501 is used for periodically discharging the ash brought by the material; the middle slag outlet 502 is used for discharging part of the slag-liquid in the slag-liquid pool when replacing the gasification agent lance; and the lower slag outlet 503 is used for discharging all the slag-liquid in the slag-liquid pool when stopping the furnace.

[0099] In a possible design, the cross-sectional area of the syngas outlet 9 is 0.8-1 m 2 , and the product inorganic mixed gas outlet speed is 30-35 m / s.

[0100] Preferably, the reactor bottoms of the primary molten metal reactor 1 and the secondary molten metal reactor 2 are provided with a molten channel 11, which is located below the first metal pool 101 and the second metal pool 201.

[0101] Illustratively, the inner walls of the primary molten metal reactor 1 and the secondary molten metal reactor 2 are provided with an electromagnetic induction external heating device.

[0102] The molten metal reactor of the present application uses molten metal as a heat source, can use the electromagnetic vortex method for heating, and maintains the heat of the metal pool.

[0103] Further, the top of the primary molten metal reactor 1 and the secondary molten metal reactor 2 is provided with an infrared temperature detector; the sidewall of the primary molten metal reactor 1 and the secondary molten metal reactor 2 is provided with an iron liquid observation communicating vessel, and liquid level information is obtained through electromagnetic association.

[0104] Illustratively, the material containing the high molecular compound is subjected to a decomposition gasification reaction in the molten metal reaction system to generate inorganic mixed gas, and the decomposition gasification reaction process is as follows:

[0105] S1-1, the material is dropped from the top of the primary molten metal reactor 1, and at the same time, the gasification agent is sprayed onto the top end of the first metal pool 101 through the gasification agent spray gun above the primary molten metal reactor 1, and the material is subjected to a primary gasification reaction under the action of the molten metal and the gasification agent, and the first mixed gas is obtained after the reaction;

[0106] S1-2, the first mixed gas is sprayed into the bottom of the molten metal of the secondary molten metal reactor 2 through the gas-liquid passage, and is subjected to a secondary gasification reaction upward through the molten metal layer and the slag liquid layer to obtain inorganic mixed gas.

[0107] Preferably, when the material is only biomass powder, the decomposition gasification reaction process is as follows: the biomass powder and the gasification agent are sprayed into the bottom of the molten metal through the biomass spray gun 13 and the gasification agent spray gun located above the secondary molten reactor 2, respectively, and subjected to a decomposition gasification reaction under the action of the molten metal and the gasification agent, and inorganic mixed gas is obtained after the reaction.

[0108] Further, the feeding and preheating system comprises a feeding tank 19, mutually parallel inverted tanks A 16 and inverted tanks B 17, and a first screw conveyor 18 and a second screw conveyor 19, the discharge outlets of the inverted tanks A 16 and the inverted tanks B 17 are connected with the inlet of the first screw conveyor 18 through pipelines, the outlet of the first screw conveyor 18 is connected with the feeding inlet of the feeding tank 19 through a pipeline, the feeding outlet of the feeding tank 19 is connected with the inlet of the second screw conveyor 20 through a pipeline, and the outlet of the second screw conveyor 20 is connected with external equipment through a sealing interface.

[0109] Preferably, the inverted tanks A 16 and B 17 are designed as backups of each other, which ensures that the continuous feeding of the material can be maintained when a single tank fails, and also enables flexible switching according to production needs, reduces downtime, and improves production efficiency.

[0110] Further, the feeding tank 19 comprises a tank body 21, a heat exchange jacket 23 arranged outside the tank body 21, a rotating shaft 29 arranged along the height direction of the tank body 21 and penetrating the tank body 21, and a stirring blade arranged along the axial direction of the rotating shaft 29.

[0111] The pushing pieces include outer pushing pieces and inner pushing pieces, wherein the outer pushing pieces and the inner pushing pieces are arranged in sequence along the rotation axis 29 in an axial direction.

[0112] The projections of the outer pushing pieces and the inner pushing pieces on a radial plane of the rotation axis 29 do not overlap.

[0113] It should be noted that, in the outer pushing pieces and the inner pushing pieces, the outer side and the inner side are relative and used for qualitatively describing the distance of the pushing pieces from the rotation axis.

[0114] Specifically, the outer pushing pieces and the inner pushing pieces are fixedly arranged on the rotation axis 29. Figures 8-22 As shown in the figure.

[0115] Further, the inner pushing pieces include a plurality of inner pushing piece units 30, each of which includes three first paddles 38 arranged in a circumferential direction of the rotation axis 29 in a uniform manner; the plane of the first paddle 38 forms an angle of 30°-85° with the axis of the rotation axis 29, and is upwardly inclined by 10°-60° along the axis of the rotation axis 29 with respect to the radial plane of the rotation axis 29.

[0116] That is, along the rotation direction of the rotation axis 29, the edge of the first paddle forms a spiral slope of 10°-60° upwardly. This design enables the inner pushing pieces to effectively push the material outwardly in the radial direction and upwardly in the axial direction when the rotation axis rotates, thereby achieving the mixing of the material and facilitating the uniform transmission of heat.

[0117] Preferably, the plane of the first paddle 38 forms an angle of 30°, 40°, 50°, 60°, 75°, 80°, or 85° with the axis of the rotation axis 29, and is upwardly inclined by 10°, 20°, 30°, 40°, 45°, 50°, or 60° along the axis of the rotation axis 29 with respect to the radial plane of the rotation axis 29. The angle of the plane of the first paddle 38 with the axis of the rotation axis 29 and the angle of the spiral slope formed by the edge of the first paddle 38 upwardly are determined according to the density and particle size of the material.

[0118] It should be noted that the paddle surface of the first paddle 38 is in the shape of an eccentric fan ring, which is a part of an eccentric circular ring formed by two eccentric and different-diameter circles and includes an inner arc, an outer arc, a long side, and a short side connecting the inner arc and the outer arc. The geometric characteristics are as follows: the circle on which the inner arc of the eccentric fan ring is located coincides with the outer circumference of the rotation axis 29, the diameter of the circle on which the outer arc of the eccentric fan ring is located is 1.5-2.5 times the diameter of the circle on which the inner arc is located, and the central angle of the eccentric fan ring with the center of the inner arc as the center is 90°-120°, not including 120°. Figure 17 , Figure 18As shown, the center of the cross section of the rotating shaft is O1, the center of the circle where the outer arc of the first paddle is located is O2, and the central angle of the first paddle is a. The design of the eccentric paddle can increase the fluid velocity and effectively suppress the stirring dead zone below the paddle, thereby improving the mixing efficiency.

[0119] The inner arc of the first paddle 38 is in contact with the rotating shaft 29, and the thickness of the first paddle 38 increases in the direction of rotation of the rotating shaft 29. The thickness design of the first paddle 38 can reduce the resistance during rotation.

[0120] Further, the outer side paddle includes a plurality of outer side paddle units, and each outer side paddle unit includes two second paddles 35 fixedly connected to the rotating shaft 29 by a first transmission shaft 36.

[0121] Specifically, the outer side paddle includes an outer side upper paddle 31 distributed in the upper region of the rotating shaft 29, and the second paddle 35 of the outer side paddle unit of the outer side upper paddle 31 is a rectangular paddle. The angle b1 between the plane of the second paddle 35 and the axis of the rotating shaft 29 is 10°-60°, and the angle c1 between the horizontal axis of the plane of the second paddle 35 and the extension line of the axis of the first transmission shaft 36 is 15°-75°.

[0122] For example, the outer side paddle includes an outer side lower paddle 32 distributed in the lower region of the rotating shaft 29, and the second paddle 35 of the outer side paddle unit of the outer side lower paddle 32 is a rectangular paddle. The angle b2 between the plane of the second paddle 35 and the axis of the rotating shaft 29 is 10°-60°, and the angle c2 between the horizontal axis of the plane of the second paddle 35 and the extension line of the axis of the first transmission shaft 36 is 15°-75°, and c2>c1.

[0123] Preferably, b1 is 10°, 20°, 30°, 40°, 45°, 50°, 60°, c1 is 15°, 20°, 30°, 40°, 45°, 50°, 60°, 75°, b2 is 10°, 20°, 30°, 40°, 45°, 50°, 60°, and c2 is 15°, 20°, 30°, 40°, 45°, 50°, 60°, 75°. The angle between the plane of the second paddle 35 and the axis of the rotating shaft 29, the angle between the horizontal axis of the plane of the second paddle 35 and the extension line of the axis of the first transmission shaft 36, and the difference between c1 and c2 are selected and adjusted according to the density and particle size of the material.

[0124] In one possible design, c1 is 45° and c2 is 60°.

[0125] It should be noted that in the projection on the radial plane of the rotating shaft 29, the two first transmission shafts 36 in the outer side paddle unit are arranged in parallel, do not pass through the center of the rotating shaft 29, and are centrally symmetric with respect to the center of the rotating shaft 29, which ensures the balance of the structure and the uniform stress of the paddle.

[0126] Specifically, when the rotating shaft rotates, the paddle of the outer lower paddle 32 has a larger angle with the extension line of the axis of the corresponding first transmission shaft 36 than the paddle of the outer upper paddle 31, that is, the outer edge of the paddle is farther away from the inner wall of the tank body, and the inclination of the paddle plane is closer to the center of the tank body. Because the pressure of the material is greater and more compact as it goes to the lower part, the angle of the paddle with the tank needs to be larger to reduce the resistance of rotation, which also plays a role in pushing the material inward and upward.

[0127] It should be noted that the number of outer paddles and the division of upper and lower regions are determined according to the diameter of the rotating shaft, the characteristics of the material, and the mixing or conveying requirements, to ensure the uniform distribution and effective movement of the material around the rotating shaft. The design of the outer paddles is coordinated with the inner paddles to achieve continuous flow of the material around the rotating shaft.

[0128] Further, after the material is fed through the feed inlet, the rotating shaft 29 continuously rotates in the feeding tank 19 at a speed greater than 60 r / min.

[0129] The rotation of the rotating shaft 29 in combination with the different paddles on the rotating shaft 29 causes the outer paddles to push the material inward and upward, and the inner paddles to push the material outward and upward, which causes the material in the tank to flow inward and outward, ensuring uniform heating of the material, and the material is constantly turned upward, which can avoid arching and clogging of the elastic material.

[0130] Preferably, the feeding tank 19 further comprises a conical discharge port 27, the upper end of which is connected below the tank body 21 through a discharge port flange 22, and the lower end of which is connected with external conveying equipment through a necked flange 28; the rotating shaft 29 passes through the discharge port flange 22 and the conical discharge port 27 area, and is fixedly installed inside the necked flange 28 of the conical discharge port 27 through a lower end bearing 33 and a lower bearing seat.

[0131] Preferably, the lower end bearing 33 of the rotating shaft 29 is made of graphite, which can withstand high temperatures of 400-500°C, does not need to be cooled, avoids taking away heat, and does not need to be dynamically sealed, is directly sealed in the feeding tank 19, and avoids the difficulty of high-temperature sealing.

[0132] Further, the outer side of the material pushing piece also includes a material hole pushing piece distributed in the area of the conical material hole 27 of the rotating shaft, the second paddle 35 of the outer side of the material pushing piece unit of the material hole pushing piece is an inverted trapezoidal paddle, the included angle b3 between the plane of the second paddle 35 and the axis of the rotating shaft 29 is 10°-60°, preferably b3 is 10°, 20°, 30°, 40°, 45°, 50°, 60°. The inverted trapezoidal paddle includes two sides, a long bottom side parallel to the first transmission shaft and a short bottom side, one of the two sides is connected with the first transmission shaft, and the long bottom side is above the short bottom side.

[0133] The shape design of the second paddle 35 in the material hole area is mainly to adapt to the conical space of the material hole area and effectively turn over the materials in the area.

[0134] Notably, the material hole flange 22 is provided with a material hole, and the cross section of the material hole is trapezoidal, which is small at the top and large at the bottom, preventing material from being stuck.

[0135] Preferably, a material shoveling pushing piece is arranged above the material hole flange 22, further avoiding the bridging of materials.

[0136] Specifically, the material shoveling pushing piece includes two third paddles 37, and the third paddles 37 are respectively fixedly connected to the rotating shaft 29 through second transmission shafts 39; the third paddle 37 is a rectangular paddle, and the included angle b4 between the plane of the third paddle 39 and the axis of the rotating shaft 29 is 60°-85°, preferably b4 is 60°, 70°, 75°, 80°, 85°; the two second transmission shafts 39 are arranged in line, and the line connecting them passes through the center of the cross section of the rotating shaft 29 at the same height.

[0137] In a possible design, the taper of the conical material hole 27 is 10°, which improves the flow characteristics of the materials and prevents the materials from arching or blocking at the material hole.

[0138] Preferably, the upper end bearing 34 of the rotating shaft is dynamically sealed at the connection with the top of the material tank body 21, and the sealing requirement is that under the condition that the sealing gas pressure is 1.0 MPa to 1.5 MPa, the leakage amount of the dynamic test is controlled to be ≤0.10 Nm 3 / h when the rotating speed is 0-60 r / min.

[0139] Further, the heat exchange jacket 23 includes an outer shell and a heating coil; the heating coil is wrapped around the outer wall of the material tank body 21, the medium inlet 24 is located at the lower end of the heating coil, and the medium outlet 25 is located at the upper end of the heating coil. Used for preheating the materials in the material tank body 21.

[0140] Preferably, fins 26 are installed outside the heating coil.

[0141] In a possible design, the cross-sectional dimension of the heating coil is 500*300mm, and the total length is 400m.

[0142] It is worth noting that in the feeding and preheating system of the application, the pouring tank A 16, the pouring tank B 17 and the feeding tank 19 have the same structure; the medium inlet of the heat exchange jacket of the feeding tank is communicated with the external air pipeline for introducing hot air; the medium outlet of the heat exchange jacket of the feeding tank is connected to the medium inlet of the pouring tank A and the medium inlet of the pouring tank B through pipelines respectively, and the medium outlet of the pouring tank A and the medium outlet of the pouring tank B are connected to the external air main pipeline through pipelines to send the heat-exchanged air back to the external air compressor.

[0143] In a possible design, control valves are arranged on each material conveying channel and heat exchange medium pipeline, and the external air temperature is 750-850℃.

[0144] The feeding and preheating system of the application avoids the bridging and blocking problems of elastic materials by adding a stirring system in the vertical tank, and solves the problem of uneven preheating of the vertical tank. The vertical tank is designed, and a plurality of groups of material pushing plate units are arranged longitudinally along the rotating shaft. Based on the angle setting of the paddle of the material pushing plate unit, and combined with the rotation of the rotating shaft, when the material pushing plate is pushed, on one hand, part of the material is pushed to the center of the tank to loosen the material upward, and on the other hand, part of the material is pushed to the outer wall of the tank to promote the flow between the inside and outside of the material, promote heat exchange, and ensure uniform heating of the material. At the same time, the material is continuously turned upward, which can effectively avoid the bridging and blocking of elastic materials.

[0145] In a possible design, when the feeding and preheating system of the application is applied to the decomposition and gasification reaction system of recyclable and renewable resources such as household garbage, industrial garbage and biomass, air exchanges heat with 1500℃ high-temperature synthesis gas generated by the decomposition and gasification reaction system in the external heat exchanger. After heat exchange, the air is heated to 750-850℃ and enters the feeding and preheating system to preheat the material, realizes waste heat recovery of the product synthesis gas, and saves energy consumption.

[0146] In summary, the present application uses a gasification agent to decompose a high polymer compound, and completely decomposes renewable and recyclable materials containing the high polymer compound into inorganic mixed gas, including CO, H2, CO2, and a small amount of escaped inorganic gas such as HCl and HBr. The mixed gas after purification is: synthetic gas (CO+H2) with a volume fraction of greater than 90%, and the balance is CO2. The mixed gas after purification can enter the subsequent processing stage, for example, through the Fischer-Tropsch synthesis reaction to produce green methanol, sustainable aviation fuel (SAF), and high-quality green plastic and other environmentally friendly products, which helps to gradually reduce the dependence on disposable petrochemical resources. A gasification system including a feeding and preheating system and a molten metal reactor is designed to realize the decomposition and gasification reaction based on molten metal. A two-stage molten metal reactor connected by a gas-liquid channel is used to decompose and gasify materials containing high molecular polymers. The crude gas (gasification gas containing organic components) generated by the gasification of the first-stage molten metal reactor is sprayed into the bottom layer of the iron liquid of the second-stage molten metal reactor through the gas-liquid channel. The crude gas is further decomposed and completely gasified by the high-temperature iron liquid layer and the high-temperature slag liquid layer of the second-stage molten metal reactor, ensuring that no high molecules escape.

[0147] The present application based on molten metal gasification method and system will be described below in conjunction with specific examples.

[0148] Example 1

[0149] This example provides a molten metal-based gasification method. As shown in Figure 1 .

[0150] Material: household garbage and industrial garbage, processing capacity is 100 tons / hour.

[0151] The gasification agent is oxygen, and the molten metal is iron liquid with a temperature of 1400-1700℃, which is carried out in the first-stage molten metal reactor 1 and the second-stage molten metal reactor 2.

[0152] The gasification process is as follows:

[0153] Step 1, briquetting pretreatment of the material to below 80mm.

[0154] Step 2, the pretreated material is sent to the surface of the iron liquid in the first-stage molten metal reactor, and oxygen is sprayed at a speed of 200m / s to the surface of the iron liquid through the gasification agent lance. The spraying of the gasification agent is stopped within 2-3min after the feeding is stopped. The material is subjected to a first-stage gasification reaction under the catalysis of the iron liquid, and the first mixed gas is obtained after the reaction.

[0155] Step 3, the first mixed gas enters the bottom of the molten metal in the secondary molten metal reactor through the gas-liquid channel, and passes through the molten metal layer and the slag liquid layer above the molten metal layer in the secondary molten metal reactor in turn, and at the same time, the oxygen gas is sprayed into the molten metal in the secondary molten metal reactor at a speed of 200 m / s through the gasification agent spray gun, the spraying of the gasification agent is stopped within 2-3 minutes after the feeding is stopped, and the first mixed gas is subjected to a secondary gasification reaction to obtain inorganic mixed gas from above the slag liquid layer.

[0156] Step 4, the inorganic mixed gas is subjected to dust removal and alkali washing purification.

[0157] After detection, the volume fraction of each component in the final product synthesis gas is: CO: 60%; H2: 39%; CO2: 1%.

[0158] Example 2

[0159] The embodiment provides a gasification method based on molten metal.

[0160] The material is biomass; the gasification agent is oxygen, and the molten metal is molten iron with a temperature of 1400-1700°C; and the process is carried out in the secondary molten metal reactor 2.

[0161] The gasification process is as follows:

[0162] Step 1, the biomass is ground into biomass powder by waste heat carbonization.

[0163] Step 2, the biomass powder is sprayed into the molten iron in the secondary molten metal reactor through the biomass spray gun at a speed of 200 m / s, and at the same time, the oxygen gas is sprayed into the molten iron through the gasification agent spray gun at a speed of 200 m / s, the spraying of the gasification agent is stopped within 2-3 minutes after the spraying of the biomass powder is stopped, and the biomass is subjected to a primary gasification reaction to obtain inorganic mixed gas from above the slag liquid layer.

[0164] Step 3, the inorganic mixed gas is subjected to dust removal and alkali washing purification.

[0165] After detection, the volume fraction of each component in the final product synthesis gas is: CO: 60%; H2: 39%; CO2: 1%.

[0166] Example 3

[0167] The embodiment provides a gasification method based on molten metal.

[0168] The material is a circuit board; the gasification agent is oxygen, and the molten metal is molten copper, and the process is carried out in the primary molten metal reactor 1 and the secondary molten metal reactor 2.

[0169] The gasification process is as follows:

[0170] Step 1, the crushed material is sent to the surface of the copper liquid of the first molten metal reactor, and oxygen is sprayed into the surface of the copper liquid at a speed of 250 m / s through the gasification agent lance. The spraying of the gasification agent is stopped within 2-3 minutes after the feeding is stopped. The material is subjected to a first gasification reaction under the action of the copper liquid and the gasification agent. The first mixed gas is obtained after the reaction. The copper in the circuit board enters the copper liquid for recovery.

[0171] Step 2, the first mixed gas enters the bottom of the copper liquid of the second molten metal reactor through the gas-liquid channel. It successively passes through the copper liquid layer and the slag liquid layer above the copper liquid layer in the second molten metal reactor. Oxygen is sprayed into the copper liquid of the second molten metal reactor at a speed of 250 m / s through the gasification agent lance. The spraying of the gasification agent is stopped within 2-3 minutes after the feeding is stopped. The first mixed gas is subjected to a second gasification reaction in this process. The inorganic mixed gas is obtained from above the slag liquid layer.

[0172] Step 3, the inorganic mixed gas is subjected to dust removal and alkali washing purification.

[0173] After detection, the volume fraction of each component in the final product synthesis gas is: CO: 60%; H2: 39%; CO2: 1%.

[0174] Example 4

[0175] This embodiment provides a molten metal reactor and a gasification system based on the molten metal reactor, as shown in Figures 2-3 and Figure 23 .

[0176] The molten metal reactor includes a first molten metal reactor 1 and a second molten metal reactor 2 that are in communication with each other through a gas-liquid channel 3, as shown in Figure 2 , Figure 3 . The first molten metal reactor 1 is internally provided with a first metal pool 101, and the second molten metal reactor 2 is internally provided with a second metal pool 201. The bottom of the second metal pool 201 is higher than the bottom of the first metal pool 101, and the first molten metal reactor 1 and the second molten metal reactor 2 are horizontally staggered.

[0177] The gas-liquid channel 3 is a semi-conical channel. The axial cross-section of the semi-conical channel is higher than the curved surface of the semi-conical channel. The semi-conical channel includes a channel inlet, a channel main body, and a channel outlet. The channel inlet is in communication with the first molten metal reactor 1, and the channel outlet is in communication with the second molten metal reactor 2. The channel inlet and the channel outlet are both semi-circular in shape. The diameter of the channel inlet is greater than the diameter of the channel outlet, and the center lines of the two are collinearly aligned. There is a distance between the center line of the channel inlet and the bottom of the first molten metal reactor 1. The bottom circular arc of the channel outlet is in close contact with the bottom of the second molten metal reactor 2.

[0178] The top of the primary molten metal reactor 1 is provided with a feeding port 102, a first gasification agent spray gun mounting port 601 and a second gasification agent spray gun mounting port 602; the top of the secondary molten metal reactor 2 is provided with a synthesis gas outlet 9; the outer side wall of the secondary molten metal reactor 2 is further provided with a third gasification agent spray gun mounting port 7 and a biomass spray gun mounting port 8; the second metal pool 201 of the secondary molten metal reactor 2 is provided with a slag liquid pool 202 above.

[0179] The gasification system comprises a feeding and preheating system, a gasification agent supply system, a molten metal reaction system connected in sequence through pipelines, a synthesis gas purification and heat exchange system and a synthesis gas storage system. Figure 23 The feeding and preheating system is connected with the inlet of the molten metal reaction system through a sealing interface; the gasification agent supply system comprises a superheated steam boiler and / or an oxygen tank, and the outlets of the two are respectively connected with the gasification agent spray guns entering the molten metal reaction system.

[0180] The synthesis gas purification and heat exchange system comprises a cyclone dust collector, a heat exchanger, a bag dust collector, a washing tower and an air compressor, the inlet of the cyclone dust collector is connected with the synthesis gas outlet of the secondary molten metal reactor, the outlet thereof is connected with the hot fluid inlet of the heat exchanger, the hot fluid outlet of the heat exchanger is connected in sequence to the bag dust collector and the washing tower, the outlet of the washing tower is connected with the synthesis gas storage system; and the air compressor is used to send air to the cold fluid inlet of the heat exchanger, and the air is sent into the heat exchange jacket of the feeding tank through pipelines after heat exchange.

[0181] The synthesis gas storage system comprises a compressor and a synthesis gas storage tank connected with the outlet of the compressor through pipelines, and the inlet of the compressor is connected with the outlet of the washing tower through pipelines.

[0182] When the gasification system is used, the material is dropped into the first metal pool 101 of the primary molten metal reactor 1 through the feeding and preheating system, and the oxygen is sprayed onto the dropping position at the upper end of the liquid surface through the first gasification agent spray gun 14 and the second gasification agent spray gun 15 on the primary molten metal reactor 1 at the same time, so that the material is subjected to the primary gasification reaction under the catalysis of the molten metal, and the first mixed gas is obtained after the reaction; the generation of the first mixed gas in the primary molten metal reactor 1 makes the pressure in the primary molten metal reactor 1 higher than that in the secondary molten metal reactor 2, so that the first mixed gas enters the bottom of the second metal pool 201 of the secondary molten metal reactor 2 through the gas-liquid passage 3 and passes through the molten metal and slag liquid layer, the oxygen is sprayed into the second metal pool 201 through the third gasification agent spray gun 12 and / or the biomass powder is sprayed into the second metal pool 201 through the biomass spray gun 13, and the inorganic mixed gas is discharged from the synthesis gas outlet 9 to the cyclone dust collector for dust removal, then enters the synthesis gas purification and heat exchange system, is subjected to further dust removal and purification after heat exchange, and finally enters the synthesis gas storage tank.

[0183] The waste heat recovery process of the system is as follows: the high-temperature product synthesis gas enters the heat exchanger hot end inlet through the pipeline, and the air compressor sends the air into the heat exchanger cold end inlet, after heat exchange, the temperature of the synthesis gas at the hot end outlet is reduced, and the temperature of the air at the cold end outlet is increased; the air is sent into the heat exchange jacket on the outer wall of the feeding tank and the unloading tank from the cold end outlet to preheat the material.

[0184] The slag discharge process of the system is as follows: the slag is discharged once a day through the upper slag discharge port 501 of the secondary molten metal reaction kettle 2, and the upper slag discharge port 501 is closed after being discharged to a specified height.

[0185] Application of the gasification system of the embodiment:

[0186] Material: household garbage, industrial garbage and biomass, treatment capacity is 100 tons / hour; gasification agent is oxygen, and molten metal is iron liquid with a temperature of 1400-1700℃.

[0187] Main design parameters of the molten metal reaction kettle: the volume of the first metal pool 101 is 56 cubic meters, the volume of the second metal pool 201 is 25 cubic meters, and the height difference between the bottom of the second metal pool 201 and the top of the first metal pool 101 is 2 meters; the iron liquid height in the secondary molten reaction kettle 2 is 2 meters, and the slag layer height is 3 meters; the gas-liquid passage 3 inlet is a semicircle with a diameter of 2 meters, and the passage outlet is a semicircle with a diameter of 0.8 meters; the synthesis gas outlet 9 cross-sectional area is 0.8m 2 The passage inlet is a semicircle with a diameter of 1.8-2 meters, and the distance from the upper end surface of the passage inlet to the bottom of the first metal pool is 2 meters; the passage outlet is a semicircle with a diameter of 0.6-0.8 meters.

[0188] When the system is used for the first time: add granular <2mm iron powder into the first metal pool 101 and the second metal pool 201 respectively, heat to a molten state, then add dolomite powder and limestone powder into the second metal pool 201 to form a slag liquid layer.

[0189] Main design parameters of the decomposition gasification reaction and subsequent treatment process: the material is dropped into the first metal pool 101 of the first molten metal reactor 1 through the feeding and preheating system, and at the same time, the oxygen is sprayed onto the liquid surface at the upper end of the first gasification agent spray gun 14 and the second gasification agent spray gun 15 at a speed of 200 m / s, and the material is subjected to the first gasification reaction under the catalysis of the iron liquid, and the first mixed gas is obtained after the reaction, and the pressure in the first molten metal reactor 1 reaches 1.5 MPa. The first mixed gas enters the bottom of the second metal pool 201 of the second molten reactor 2 through the gas-liquid channel 3 at a speed of 50-150 m / s and passes through the molten metal and slag liquid layer, and at the same time, the third gasification agent spray gun 12 sprays oxygen at a speed of 200 m / s to the second metal pool 201, and the biomass spray gun 13 sprays biomass powder at a speed of 200 m / s to the second metal pool 201, and the product inorganic mixed gas is discharged from the synthesis gas outlet 9 at a speed of 30-35 m / s to the cyclone dust collector for dust removal, and then enters the synthesis gas purifying agent heat exchange system, and after heat exchange, the temperature is reduced to below 300°C, and further dust removal and purification are carried out, and then the synthesis gas storage tank is entered.

[0190] Main design parameters of the waste heat recovery process: the product inorganic mixed gas at a temperature of 1500°C enters the heat exchanger through the pipeline, and the air compressor sends air into the cold end inlet of the heat exchanger, and after heat exchange, the inorganic mixed gas at the hot end outlet is at a temperature of 300°C, and the air at the cold end outlet is at a temperature of 850°C; the air is sent into the heat exchange jacket 23 of the outer wall of the feeding tank 19 and the material pouring tank to preheat the material to 400°C.

[0191] Example 5

[0192] This embodiment provides a preheating and feeding system. As shown in Figures 4-16 .

[0193] The decomposition gasification reaction system is used for feeding of recyclable and renewable resources such as household garbage, industrial garbage and biomass.

[0194] The feeding and preheating system comprises a material pouring tank A 16 and a material pouring tank B 17, a feeding tank 19 and a first screw conveyor 18, and a second screw conveyor 20 which are connected in parallel, the discharge outlets of the material pouring tank A 16 and the material pouring tank B 17 are respectively connected with the inlet of the first screw conveyor 18 through pipelines, the outlet of the first screw conveyor 18 is connected with the feeding inlet of the feeding tank 19 through a pipeline, the feeding outlet of the feeding tank 19 is connected with the inlet of the second screw conveyor 20 through a pipeline, and the outlet of the second screw conveyor 20 is connected with external equipment through a sealing interface.

[0195] The feeding tank 19 comprises a tank body 21, a heat exchange jacket 23 arranged outside the tank body 21, a rotating shaft 29 arranged along the height direction of the tank body 21 and penetrating the tank body, and a raking blade arranged along the axial direction of the rotating shaft 29; the projection of the outer raking blade and the inner raking blade on the radial plane of the rotating shaft does not overlap.

[0196] The outer raking blade and the inner raking blade are fixedly arranged on the rotating shaft. The inner raking blade comprises an inner raking blade unit 30, which comprises three first paddles 38 arranged uniformly in the circumferential direction of the rotating shaft 29; the plane of the first paddle 38 forms an angle of 30°-85° with the axis of the rotating shaft 29, and is upwardly inclined by 10°-60° along the axis of the rotating shaft 29 with respect to the radial plane of the rotating shaft 29.

[0197] The outer raking blade comprises a plurality of outer raking blade units, each of which comprises two second paddles 35 fixedly connected to the rotating shaft 29 by a first transmission shaft 36.

[0198] The outer raking blade comprises an outer upper raking blade 31 arranged in the upper region of the rotating shaft, the second paddle 35 of the outer raking blade unit of the outer upper raking blade 31 being a rectangular paddle; the plane of the second paddle 35 forms an angle b1 of 10°-60° with the axis of the rotating shaft 29, and the horizontal axis of the plane of the second paddle 35 forms an angle c1 of 15°-75° with the extension line of the axis of the first transmission shaft 36.

[0199] Exemplarily, the outer raking blade comprises an outer lower raking blade 32 arranged in the lower region of the rotating shaft, the second paddle 35 of the outer raking blade unit of the outer lower raking blade 32 being a rectangular paddle, the plane of the second paddle 35 forming an angle b2 of 10°-60° with the axis of the rotating shaft 29, and the horizontal axis of the plane of the second paddle 35 forming an angle c2 of 15°-75° with the extension line of the axis of the first transmission shaft 36; and c2>c1.

[0200] The feeding tank 19 further comprises a conical discharge opening 27, the upper end of the conical discharge opening 27 being connected below the tank body 21 by a discharge opening flange 22, and the lower end of the conical discharge opening 27 being connected to external conveying equipment by a necked flange 28; the rotating shaft 29 penetrates the region of the discharge opening flange 22 and the conical discharge opening 27, and is fixedly installed inside the necked flange 28 of the conical discharge opening 27 by a lower end bearing 33 and a lower bearing seat.

[0201] The outer side material pushing piece further comprises a material falling port pushing piece distributed in the area of the conical material falling port 27 of the rotating shaft, the second paddle 35 of the outer side material pushing piece unit of the material falling port pushing piece is an inverted trapezoidal paddle, and the included angle b3 between the plane of the second paddle 35 and the axis of the rotating shaft 29 is 10-60 degrees. The inverted trapezoidal paddle comprises two sides, a long bottom side parallel to the first transmission shaft and a short bottom side, one of the two sides is connected with the first transmission shaft, and the long bottom side is above the short bottom side.

[0202] A material shoveling pushing piece is arranged above the material falling port flange 22, the material shoveling pushing piece comprises two third paddles 37, the third paddles 37 are fixedly connected to the rotating shaft 29 through second transmission shafts 39 respectively, the third paddles 37 are rectangular paddles, the included angle b4 between the plane of the third paddles 37 and the axis of the rotating shaft 29 is 60-85 degrees, and the two second transmission shafts 39 are arranged in line and the line connecting the two second transmission shafts 39 passes through the center of the cross section of the rotating shaft 29 at the same height.

[0203] The material pouring cans A 16 and B 17 have the same structure as the material loading can 19, and the material pouring can A 16 and the material pouring can B 17 are standby for each other.

[0204] The heat exchange jacket 23 comprises an outer shell, a heating coil, a medium inlet 24 and a medium outlet 25, the heating coil is arranged around the outer wall of the material can body 21, and the two ends of the heating coil are connected to the medium inlet 24 and the medium outlet 25 through the outer shell respectively, the medium inlet 24 is located at the lower end of the heating coil, and the medium outlet 25 is located at the upper end of the heating coil; and fins 26 are arranged outside the heating coil.

[0205] When the feeding and preheating material system is used:

[0206] The material is conveyed from the external material bin to the material pouring can A 16 (the material pouring can B 17 is standby), the feeding is completed through the feeding port of the material pouring can A 16; meanwhile, the rotating shaft of the material pouring can A 16 continuously rotates in the material loading can, the material falls into the first screw conveyor 18 through the conical material falling port of the material pouring can A 16, and then enters the feeding port of the material loading can 19 from the outlet of the first screw conveyor 18; the rotating shaft of the material loading can 19 also continuously rotates, the material enters the second screw conveyor 20 through the conical material falling port of the material loading can 19, and is finally conveyed to the decomposition gasification reaction system; the outlet of the second screw conveyor 20 is connected with the decomposition gasification reaction system through a high-pressure-resistant sealing interface, and a water cooling system is arranged outside the high-pressure-resistant sealing interface.

[0207] At the same time when the material enters the material pouring tank A16, the external air enters the heat exchange jacket 23 of the system through the medium inlet 24 of the heat exchange jacket 23, and after completing heat exchange, returns to the air compressor through the medium outlet of the material pouring tank A16, so as to realize the recycling of the heat exchange air. Before entering the system, the air exchanges heat with the 1500℃ high-temperature synthesis gas generated by the decomposition gasification reaction system in the external heat exchanger, and after heat exchange, the air is heated to 850℃. Before the material enters the decomposition gasification reaction system, the material is preheated to 400℃ through the above heat exchange process.

[0208] Application of the material feeding and preheating system:

[0209] The decomposition gasification reaction system is used for feeding of recyclable and renewable resources such as household garbage, industrial garbage and biomass, and the conveying capacity is 200m 3 / h.

[0210] Main equipment parameters of the system: the diameter of the material tank body 21 is 4 meters, the lower diameter of the conical material falling port 27 is 1 meter, and the taper is 10°; the cross-sectional size of the heating coil is 500*300mm, and the total length is 400m; the number of the inner material stirring blade units is 8; the plane of the first paddle 38 forms a 60° angle with the axis of the rotating shaft 29, and simultaneously, the plane is upwardly inclined by 30° along the axis of the rotating shaft 29 with respect to the radial plane of the rotating shaft 29; b1=b2=b3=30°; b4=60°; c1=45°; c2=60°.

[0211] Main operation parameters of the system: the rotating shafts of the material pouring tank and the material feeding tank rotate at a speed of 65r / min.

[0212] Main preheating parameters: before entering the system, the air exchanges heat with the 1500℃ high-temperature gas generated by the decomposition gasification reaction system in the external heat exchanger, and after heat exchange, the air is heated to 850℃. Before the material enters the decomposition gasification reaction system, the material is preheated to 400℃ through the above heat exchange process.

[0213] During the operation of the whole system, the material conveying is smooth, and no blocking or bridging phenomenon occurs, and the material temperature distribution is uniform.

[0214] In summary, the present application uses a gasifying agent to decompose the high molecular compound with molten metal as the medium, and completely decomposes the renewable and recyclable material containing the high molecular compound into inorganic mixed gas, including CO, H2, CO2, and a small amount of escaped inorganic gas such as HCl and HBr. The mixed gas after purification is: synthetic gas (CO+H2) with a volume fraction of more than 90%, and the balance is CO2. The mixed gas after purification can enter the subsequent processing stage, for example, through the Fischer-Tropsch synthesis reaction to produce green methanol, sustainable aviation fuel (SAF), and high-quality green plastic and other environmentally friendly products, which helps to gradually reduce the dependence on disposable petrochemical resources; and a gasification system including a feeding and preheating system and a molten metal reactor is designed to realize the decomposition gasification reaction based on molten metal; a two-stage molten metal reactor connected by a gas-liquid channel is used to decompose and gasify the material containing high molecular polymers. The crude gas (gasification gas containing organic components) generated by the first-stage molten metal reactor is sprayed into the bottom layer of the second-stage molten metal reactor through the gas-liquid channel. The crude gas is further decomposed and completely gasified by the high-temperature iron liquid layer and the high-temperature slag liquid layer of the second-stage molten metal reactor, ensuring that no high molecules escape.

[0215] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and should be covered within the protection scope of the present application.

Claims

1. A gasification method based on molten iron, characterized in that, Using molten iron as a medium and heat source, materials containing high molecular weight compounds undergo decomposition and gasification reactions under the action of a gasifying agent to generate inorganic mixed gas, including CO and H2. The decomposition and gasification reaction is carried out in a molten metal-based gasification system, which includes a primary molten metal reactor and a secondary molten metal reactor that are interconnected by a gas-liquid channel. The primary molten metal reactor has a first metal pool inside, and the secondary molten metal reactor has a second metal pool inside, wherein the bottom of the second metal pool is higher than the bottom of the first metal pool, and the primary and secondary molten metal reactors are horizontally staggered. The decomposition and gasification reaction process is as follows: The material is pre-treated by briquetting to a thickness of less than 80mm; S1-1. The material is dropped from the top of the primary molten metal reactor (1). At the same time, the gasifying agent is sprayed onto the upper part of the liquid surface of the first metal pool (101) through the gasifying agent spray gun above the primary molten metal reactor (1). The material undergoes a primary gasification reaction under the action of molten metal and gasifying agent, and the first mixed gas is obtained after the reaction. This increases the internal pressure of the primary molten metal reactor (1) to 1.5~1.8MPa, which increases the pressure difference between the primary molten metal reactor (1) and the secondary molten metal reactor (2). The angle between the gasifying agent spray gun and the horizontal direction is 45°; S1-2 Under the action of pressure difference, the first mixed gas is injected into the bottom of the molten metal in the secondary molten metal reactor (2) at a speed of 50-150m / s through the gas-liquid channel, and then passes through the molten metal layer and slag liquid layer to carry out secondary gasification reaction to obtain inorganic mixed gas; The inorganic mixture after purification is: CO + H2 with a volume fraction greater than 90% and the balance being CO2; The gas-liquid channel is a semi-conical channel; the semi-conical channel includes a channel inlet, a channel body, and a channel outlet. The channel inlet is connected to the primary molten metal reactor, and the channel outlet is connected to the secondary molten metal reactor. Both the channel inlet and the channel outlet are semi-circular in shape, and the diameter of the channel inlet is larger than the diameter of the channel outlet. There is a distance between the centerline of the channel inlet and the bottom of the primary molten metal reactor. The main body of the channel includes a primary molten metal reactor sidewall section and a secondary molten metal reactor sidewall section. The channel inlet is formed on the inner sidewall of the primary molten metal reactor (1), and the channel outlet is formed on the inner sidewall of the secondary molten metal reactor (2). The axial cross-section of the main body of the channel is semi-circular, with the diameter of the semi-circle gradually decreasing from the channel entrance to the channel exit, forming a gradually narrowing conical path.

2. A vaporization method based on molten copper liquid, characterized in that, Using molten copper as a medium and heat source, materials containing high molecular weight compounds undergo decomposition and gasification reactions under the action of a gasifying agent to generate an inorganic mixed gas, including CO and H2. The decomposition and gasification reaction is carried out in a molten metal-based gasification system, which includes a primary molten metal reactor and a secondary molten metal reactor that are interconnected by a gas-liquid channel. The primary molten metal reactor has a first metal pool inside, and the secondary molten metal reactor has a second metal pool inside, wherein the bottom of the second metal pool is higher than the bottom of the first metal pool, and the primary and secondary molten metal reactors are horizontally staggered. The decomposition and gasification reaction process is as follows: The material is pre-treated by briquetting to a thickness of less than 80mm; S1-1. The material is dropped from the top of the primary molten metal reactor (1). At the same time, the gasifying agent is sprayed onto the upper part of the liquid surface of the first metal pool (101) through the gasifying agent spray gun above the primary molten metal reactor (1). The material undergoes a primary gasification reaction under the action of molten metal and gasifying agent, and the first mixed gas is obtained after the reaction. This increases the internal pressure of the primary molten metal reactor (1) to 1.5~1.8MPa, which increases the pressure difference between the primary molten metal reactor (1) and the secondary molten metal reactor (2). The angle between the gasifying agent spray gun and the horizontal direction is 45°; S1-2 Under the action of pressure difference, the first mixed gas is injected into the bottom of the molten metal in the secondary molten metal reactor (2) at a speed of 50-150m / s through the gas-liquid channel, and then passes through the molten metal layer and slag liquid layer to carry out secondary gasification reaction to obtain inorganic mixed gas; The inorganic mixture after purification is: CO + H2 with a volume fraction greater than 90% and the balance being CO2; The gas-liquid channel is a semi-conical channel; the semi-conical channel includes a channel inlet, a channel body, and a channel outlet. The channel inlet is connected to the primary molten metal reactor, and the channel outlet is connected to the secondary molten metal reactor. Both the channel inlet and the channel outlet are semi-circular in shape, and the diameter of the channel inlet is larger than the diameter of the channel outlet. There is a distance between the centerline of the channel inlet and the bottom of the primary molten metal reactor. The main body of the channel includes a primary molten metal reactor sidewall section and a secondary molten metal reactor sidewall section. The channel inlet is formed on the inner sidewall of the primary molten metal reactor (1), and the channel outlet is formed on the inner sidewall of the secondary molten metal reactor (2). The axial cross-section of the main body of the channel is semi-circular, with the diameter of the semi-circle gradually decreasing from the channel entrance to the channel exit, forming a gradually narrowing conical path.

3. The gasification method according to claim 1 or 2, characterized in that, The vaporizing agent is one or a mixture of two of oxygen and superheated steam.

4. The gasification method according to claim 3, characterized in that, The gasifying agent is sprayed into the molten metal through a spray gun at a speed of 200-250 m / s.

5. The gasification method according to claim 1 or 2, characterized in that, The materials containing polymeric compounds include one or more of the following: municipal solid waste, industrial waste, and biomass.

6. The gasification method according to claim 5, characterized in that, The material is biomass. Before the decomposition and gasification reaction, the biomass is processed into powder and sprayed into molten metal through a spray gun. Under the action of molten metal and gasifying agent, the decomposition and gasification reaction takes place. The spraying speed of the biomass powder is 200~250m / s.

7. The gasification method according to claim 6, characterized in that, The inorganic mixed gas passes upward through the slag-liquid layer for filtration.

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