A device and method for producing high-grade hydrogen-rich syngas by pyrolyzing urban organic waste

Abstract

The present invention discloses a device and method for pyrolyzing urban organic waste to produce high-grade hydrogen-rich synthesis gas, and specifically relates to the technical field of urban waste treatment. The device comprises a reaction tower with two upper and lower moving beds. The upper moving bed adopts an oxygen-deficient environment, which can ensure that the heteroatoms contained in the product of the pre-oxidation section are effectively escaped; the temperature and oxygen content are increased in the carbonization section of the lower moving bed, and the appropriate ratio of carbon / oxygen / steam is controlled at the same time, so that the hydrogen content of the hydrogen-rich high-grade synthesis gas can reach more than 99%. After the domestic organic waste is treated by the device and method of the present invention, on the one hand, it can be ensured that N, O, S, and Cl after dissociation all escape from the reactor as their hydrogen-containing compounds NH3, CO2 (H2CO3), H2S, and HCl gases, and can be completely removed when entering the deacidification tower, and no longer appear in the form of their oxides; on the other hand, after being treated by the two-step method, the obtained hydrogen-rich high-grade synthesis gas contains almost no non-flammable nitrogen, which greatly improves the utilization value of cracked combustible gas.

Description

Technical Field

[0001] The invention relates to the technical field of urban waste treatment, and in particular to a device and method for pyrolyzing urban organic waste to produce high-grade hydrogen-rich synthesis gas. Background Art

[0002] The treatment of urban organic waste is the main content of modern urban waste disposal. The preciousness of land has led cities that lack industrial land to turn their attention to incineration to dispose of solid waste. However, due to the difficulty in solving toxic dioxins and fly ash, this technology has been criticized. Given that organic waste is full of heat / energy, people naturally think of converting it into synthesis gas (water gas) through thermal cracking and gasification, while also obtaining heat for further recycling. However, to date, there has been no precedent for large-scale and extensive industrial application of urban organic waste. The reason is that the thermal cracking and gasification of organic waste is an endothermic process, and sufficient heat is required to achieve cracking and gasification. The usual practice is to partially burn urban organic waste to generate a high enough temperature for the cracking reaction to continue, but it is well known that the introduction of air to assist combustion will inevitably bring in useless and non-flammable nitrogen, which in turn causes the concentration of combustible components in the generated synthesis gas to drop rapidly, thereby losing its practical application value; and the introduction of pure oxygen alone, the operation of oxygen control is complicated, the operating cost is high, and the safety is poor.

[0003] In the prior art, garbage is usually treated by a pyrolysis gasification furnace. During the pyrolysis gasification process, air is generally introduced into the pyrolysis furnace to burn part of the garbage to generate heat and maintain the temperature of the entire pyrolysis gasification process. However, the following problems generally exist:

[0004] 1. Since the air contains a large amount of non-flammable nitrogen, the nitrogen content in the combustible gas after cracking and gasification is very high, while the content of combustible components in the combustible gas is very low, usually only about 20% of its volume or less, which greatly reduces the available value and has no commercial application prospects.

[0005] 2. During the cracking and gasification process, pure oxygen can be used as a combustion aid to reduce useless nitrogen. However, since the amount of oxygen needs to be precisely controlled throughout the process and it cannot be excessively oxygenated, the operation and equipment used will be very complicated and costly; using pure oxygen will greatly reduce safety.

[0006] Chinese patent CN106196082A, a multi-stage clean and efficient domestic waste pyrolysis gasification furnace and process, including a furnace body, a fully enclosed two-way feed pipe is installed on the two opposite sides of the upper end of the furnace body, an internal compaction and air-breaking plate is suspended at the upper end of the furnace body, an internal air guide pipe is vertically installed around the inner wall of the furnace body, the upper end of the internal air guide pipe is connected to the outlet pipe, and a through-gas guide ignition pipe is connected between the outlet pipe and the furnace body cavity, the through-gas guide ignition pipe passes through the internal compaction and air-breaking plate and extends into the lower part of the furnace body cavity, and the furnace body is also equipped with a regenerative gas combustion-supporting system. The upper stage gas with more impurities in this invention is returned to the fire layer for combustion through the regenerative gas combustion-supporting system, and the impurities and pollutants are subjected to high-temperature treatment to make the gas cleaner. The combustion-supporting system can also speed up the combustion speed and increase the combustion temperature, so that the garbage pyrolysis and gasification efficiency is higher, and the garbage heating and efficient use of heat energy can be achieved. However, this patent still does not solve the problem that the obtained combustible gas contains nitrogen, thereby reducing the concentration of the combustible gas. In addition, the upper stage fuel gas with more impurities is returned to the fire layer through the regeneration fuel gas combustion-supporting system for combustion, and the impurity pollutants are treated at high temperature, that is, the heteroatoms form their oxides, such as the S element is oxidized to SO2, and the Cl element may be dioxin.

[0007] Chinese patent CN110846082A, a system for preparing high calorific value fuel gas by cracking and gasification, including an oxygen storage tank and a cracking and gasification furnace, the cracking and gasification furnace including: a furnace body, with an oxygen injection port, and a combustible gas outlet at the top; an ash pan, arranged at the bottom of the furnace body, capable of rotating relative to the furnace body, and the lower end of the furnace body is located in the ash pan; a grate, fixed to the ash pan, with a circle of slag slides around the lower part of the grate, the ash pan is used to load coolant, the bottom of the grate has a first oxygen inlet channel, and the oxygen injection port is aligned with the slag slide; the outlet of the oxygen storage tank is connected to a gas supply main pipe, the gas supply main pipe is connected to the first oxygen inlet channel through a first pipeline, the gas supply main pipe is connected to the oxygen injection port through a second pipeline, a first flow control valve is installed on the first pipeline, and a second flow control valve is installed on the second pipeline. This application uses pure oxygen to carry out cracking and gasification combustion of part of the garbage, which can obtain combustible gas with higher purity and higher calorific value than directly using air for pyrolysis and gasification. However, this patent requires the use of high oxygen for pyrolysis and gasification, which is expensive and requires high equipment. The use of pure oxygen to assist combustion also greatly reduces the operational safety. Moreover, if the oxygen cannot be accurately controlled, it is no different from the incineration method.

[0008] Therefore, the thermal cracking and gasification process of urban garbage has rarely been used in large-scale industrial applications. Summary of the invention

[0009] To this end, the present invention provides a device and method for pyrolyzing urban organic waste to produce high-grade hydrogen-rich synthesis gas to solve the above-mentioned problems.

[0010] Principle of the present invention:

[0011] The present invention adopts a staged decomposition process: a pre-oxidation stage and a carbonization stage. The components of domestic organic waste are complex, and the pre-oxidation stage adopts a gradient temperature: between 200-600°C, the purpose of which is to achieve dehydration and desolvation within the compound molecules and eliminate heteroatomic substances in the gasified waste, such as nitrogen-containing compounds, sulfur-containing compounds, chlorine-containing compounds, oxygen-containing compounds, etc. Among them, at 200-300°C, these heteroatomic compounds or groups are freed, cracked, and disproportionated, thereby detaching, and the remaining is a pure carbon structure framework; then the temperature is appropriately increased to between 400-600°C to achieve the dehydrogenation reaction of the organic compound, that is, to achieve olefination and aromatization, and continuously reduce the hydrogen content in the compound until it is completely carbonized. In this case, the compound no longer contains the above-mentioned heteroatomic components.

[0012] The temperature is further increased in the carbonization section, and the carbon skeleton is reformed to form H2 and CO in the presence of hot water vapor and carbon dioxide. CO then reacts with H2O to produce high-purity hydrogen. Among them, CO2 is reduced and reformed by C to produce 2 moles of CO, and this cycle repeats.

[0013] The temperature in the carbonization stage is increased by using a low-O2 mixed combustion-supporting gas made of CO2 and water vapor. The carbonization stage no longer contains any harmful syngas compounds containing elements such as N, O, S, and Cl.

[0014] During the entire thermal cracking gasification process, N, O, S, and Cl all escape from the reactor in the form of their hydrogen-containing compounds NH3, CO2 (H2CO3), H2S, and HCl gases, and no longer appear in the form of their oxides. Therefore, there will be no dioxin components; in addition, particulate matter also remains in the reactor in the form of slag, and no longer is discharged in the form of fly ash to affect the subsequent air quality.

[0015] In order to achieve the above object, the present invention provides the following technical solutions:

[0016] According to one aspect of the present invention, a device for pyrolyzing urban organic waste to produce high-grade hydrogen-rich syngas is provided, the device comprising: a reaction tower, wherein the reaction tower comprises an upper moving bed and a lower moving bed, and the raw materials carbonized in the upper moving bed enter the lower moving bed for reaction;

[0017] The upper moving bed is connected in sequence to an electric decoking device for removing tar, and a deacidification tower for spraying to remove acidic and water-soluble gases; the deacidification tower is connected to a burner, and the heat generated by the combustion of gas in the burner enters the raw material pretreatment device for dehydration and drying pretreatment of the raw material. The pretreated raw material enters the upper moving bed through the feed for preoxidation section, and the raw material after the preoxidation section enters the lower moving bed;

[0018] The lower moving bed is connected to a CO2 removal reaction tower, the removed CO2 enters a CO2 recovery device for recovery, and the gas from which CO2 is removed enters a high-grade gas collection device for recovery;

[0019] The steam generated by the dehydration and drying pretreatment of the raw materials is usually returned to the pre-oxidation section and carbonization section of the upper moving bed or the lower moving bed to provide the water steam required.

[0020] Furthermore, the diameter of the lower moving bed is 60%-80% of the diameter of the upper moving bed. Since the volume of the solids is reduced by about 50% due to gasification (which is conducive to the downward movement of the materials), the volume of the lower reaction tower is also reduced accordingly.

[0021] Furthermore, a material discharge device is provided at the bottom of the upper moving bed and the lower moving bed.

[0022] Furthermore, the feeding device is provided with fins for feeding and stirring the materials and a nozzle with a roller for heating the materials.

[0023] Furthermore, the fins are inclined at an angle of 30 to 60 degrees; each layer of the material discharge device of the multi-layered stirring device is provided with 3 to 5 fins; the material rotates along the fins under the action of gravity, descends under the auxiliary force of the roller, and forms a moving bed with an automatic mechanical stirring function. Specifically, the material falls under the action of gravity; due to the reduction in volume of the solids after cracking and gasification, a certain gap is formed, and the upper material will be squeezed downward; but it is blocked by the fixed fins. Due to the 30 to 60° angle of the fins, the material moves downward along the tangent direction of the angle; that is, the upper corner of the fin moves to its lower corner and rotates relative to the central axis of the tower body; the nozzle actively rotates in the same direction, and when there is an obstacle, the rotation of the nozzle will further pull the material downward. In short, the material rotates along the 30 to 60° angle of the fins, thereby achieving a stirring effect.

[0024] Furthermore, the roller nozzle is placed at the lower edge of the fin.

[0025] Furthermore, the device is also provided with a low-grade synthesis gas outlet and a high-grade synthesis gas outlet, wherein the low-grade synthesis gas outlet is located at the upper end of the upper moving bed, and is used for the low-grade synthesis gas to enter the electric decoking device from the upper moving bed; the high-grade synthesis gas outlet is located at the upper end of the lower moving bed, and is used for the high-grade synthesis gas to enter the CO2 removal reaction tower from the lower moving bed.

[0026] According to another aspect of the present invention, a method for producing high-grade hydrogen-rich syngas by pyrolyzing urban organic waste is provided, the method comprising:

[0027] Step 1: Pre-oxidation of raw materials

[0028] The raw materials pre-treated by dehydration and drying in the raw material pre-treatment device are fed into the upper moving bed and then subjected to the first stage of anoxic pyrolysis and gasification at medium and low temperature. The low-grade synthesis gas produced is successively removed from the tar by the electric decoking device through the low-grade synthesis gas outlet, and the acid and water-soluble gas are removed by the deacidification tower, and then enters the burner for combustion. The heat after combustion enters the raw material pre-treatment device for dehydration and drying pre-treatment of the raw materials. The raw materials produced by the pyrolysis and gasification in the upper moving bed are passed down through the unloading device and enter the lower moving bed for further reaction.

[0029] Step 2: Preparation of high-quality hydrogen-rich syngas in the carbonization section

[0030] After water vapor and oxygen are injected into the lower moving bed, the second stage hydrogen-rich gas production reaction is carried out under micro-oxygen conditions. The high-grade synthesis gas obtained is passed through a CO2 removal reaction tower to remove CO2, and the resulting hydrogen-rich high-grade synthesis gas enters a high-grade gas collection device for recovery.

[0031] Note: The reaction in the upper moving bed is an oxygen-deficient environment, which is conducive to the pyrolysis and carbonization of the raw materials to produce low-grade synthesis gas. In this reaction, due to the presence of N2, the combustible gas content in the pyrolysis synthesis gas is about 20%; in the lower moving bed, the reaction is a micro-oxygen environment, and the oxygen content is controlled to be 2%~15%. The oxygen content and water content can be controlled to control the composition of the synthesis gas and increase the H2 content.

[0032] Furthermore, in the step 1, the temperature of the first stage of anaerobic pyrolysis and gasification at medium and low temperature is a gradient temperature; specifically, the temperature of the combustion aid inlet, i.e., the flare outlet, is 400-600°C, and the temperature of the synthesis gas outlet, i.e., the tower outlet end, is 200-300°C.

[0033] Furthermore, in step 2, the oxygen content in the micro-oxygen condition is 2% to 15%.

[0034] Furthermore, in the step 2, the reaction temperature is 600-800°C.

[0035] The present invention has the following advantages:

[0036] After treating domestic organic waste with the device and method of the present invention, on the one hand, it can be ensured that N, O, S, and Cl escape from the reactor in the form of their hydrogen-containing compounds NH3, CO2 (H2CO3), H2S, and HCl after dissociation, and can be completely removed after entering the deacidification tower, and no longer appear in the form of their oxides. Therefore, there will be no dioxin components, and particulate matter will also remain in the reactor in the form of slag, and will no longer affect the subsequent air quality in the form of fly ash; on the other hand, after the two-step treatment, the obtained hydrogen-rich high-grade synthesis gas contains almost no nitrogen, which greatly improves the commercial utilization value of cracked combustible gas.

[0037] The reaction tower of the present invention adopts two parts: an upper moving bed and a lower moving bed. The upper moving bed adopts an oxygen-deficient environment to ensure that the product of the pre-oxidation section does not contain heteroatoms; the temperature and oxygen content are increased in the carbonization section of the lower moving bed, and the oxygen content is controlled at the same time, so that the hydrogen content of the hydrogen-rich high-grade synthesis gas can reach more than 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0039] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0040] Figure 1 A device for producing high-grade hydrogen-rich synthesis gas by pyrolyzing urban organic waste provided in Example 1 of the present invention;

[0041] Figure 2 An enlarged view of the specific structure of the reaction tower provided in Example 1 of the present invention;

[0042] Figure 3 This is a diagram showing the internal structure of the feeding device provided in Example 1 of the present invention;

[0043] In the figure: 1-upper moving bed; 2-lower moving bed; 3-electric decoking device; 4-deacidification tower; 5-water treatment unit; 6-burner; 7-raw material pretreatment device; 8-CO2 removal reaction tower; 9-high-grade gas collection device; 10-CO2 recovery device; 11-slag collection device; 12-low-grade synthesis gas outlet; 13-high-grade synthesis gas outlet; 14-fin; 15-nozzle with roller. DETAILED DESCRIPTION

[0044] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] This embodiment provides a device for pyrolyzing urban organic waste to produce high-grade hydrogen-rich synthesis gas, such as Figure 1 As shown:

[0047] The device comprises: a reaction tower, wherein the reaction tower (such as Figure 2 As shown) comprises an upper moving bed 1 and a lower moving bed 2, and the raw materials carbonized in the upper moving bed 1 enter the lower moving bed 2 for reaction;

[0048] The upper moving bed 1 is connected in sequence to an electric decoking device 3 for removing tar, and a deacidification tower 4 for spraying and removing acidic and water-soluble gases; the deacidification tower 4 is connected to a burner 6, and the heat generated by the combustion of gas in the burner 6 enters the raw material pretreatment device 7 for dehydration and drying pretreatment of the raw material. The pretreated raw material enters the upper moving bed 1 through the feed for preoxidation section, and the raw material after the preoxidation section enters the lower moving bed 2;

[0049] The liquid after the acid removal tower 4 absorbs the acid and water-soluble gas enters the water treatment unit 5 for treatment and then is discharged from the system;

[0050] The lower moving bed 2 is connected to a CO2 removal reaction tower 8, the removed CO2 enters a CO2 recovery device 10 for recovery, and the gas from which CO2 is removed enters a high-grade gas collection device 9 for recovery.

[0051] The lower moving bed 2 is 60%-80% of the diameter of the upper moving bed 1;

[0052] The bottom of the upper moving bed 1 and the bottom of the lower moving bed 2 are both provided with a material discharge device;

[0053] The feeding device (such as Figure 3 As shown in the figure, fins 14 for stirring the material and a nozzle 15 with rollers for heating the material are provided; the material rotates along the fins under the action of gravity, descends under the auxiliary force of the rollers, and forms a moving bed with automatic mechanical stirring function;

[0054] The fins 14 are inclined at an angle of 30 to 60 degrees; one layer of the feeding device is provided with 3 to 5 fins 14;

[0055] The roller nozzle 15 is placed at the lower edge of the fin 14;

[0056] Description: The fins 14 are composed of three to five pieces, each forming a layer, and at least one layer of multi-layer assembly devices are placed inside the tower and arranged along the tower wall; the roller nozzle 15 is placed at the lower edge of the fins 14;

[0057] The device is also provided with a low-grade syngas outlet 12 and a high-grade syngas outlet 13, wherein the low-grade syngas outlet 12 is located at the end of the upper moving bed 1, and is used for the low-grade syngas to enter the electric decoking device 3 from the upper moving bed 1; the high-grade syngas outlet 13 is located at the end of the lower moving bed 2, and is used for the high-grade syngas to enter the CO2 removal reaction tower 8 from the lower moving bed 2;

[0058] The device also includes a slag collecting device 11; the collected slag is rich in K, Si, P and C, and can be used for subsequent preparation of compound fertilizer, thereby achieving full resource utilization.

[0059] Example 2

[0060] This embodiment uses the device of embodiment 1 to treat domestic organic waste:

[0061] Step 1: Pre-oxidation of raw materials

[0062] The raw materials pre-treated by dehydration and drying in the raw material pre-treatment device 7 are fed into the upper moving bed 1 and then subjected to the first stage of anoxic pyrolysis and gasification at medium and low temperature. The low-grade synthesis gas produced is successively removed from the tar by the electric decoking device 3 through the low-grade synthesis gas outlet 12, and the water-soluble and acidic gases are removed by the deacidification tower 4, and then enters the burner 6 for combustion. The heat after combustion enters the raw material pre-treatment device 7 for dehydration and drying pre-treatment of the raw materials. The raw materials produced by the pyrolysis and gasification in the upper moving bed 1 are passed down through the unloading device and enter the lower moving bed 2 for further reaction.

[0063] The first stage of anoxic pyrolysis and gasification at medium and low temperature in the upper moving bed 1 is a gradient temperature, specifically: the combustion aid inlet, i.e., the flare outlet temperature is 400-600°C, and the synthesis gas outlet, i.e., the tower outlet end temperature is 200-300°C;

[0064] This design can effectively intercept most of the tar components that may be produced. At this stage, low-grade synthesis gas is produced, and the content of CO+H2 is about 20%. The gas still contains a large amount of impurities such as N2, CO2, H2S, HCl, NH3, and some gaseous tar and other impurities. The low-grade synthesis gas is successively decoked by the electric decoking device 3 and sprayed and deacidified by the deacidification tower 4 (the content of the synthesis gas at this time varies from 20% to 60%, and the purity is already high except for nitrogen and water vapor, and it does not contain other heteroatoms (S, Cl, etc.) pollutants, and can produce 2000-3000 joules. Heat, which can be directly burned in the burner 6 without adding other combustible gases) enters the burner 6 as fuel to generate heat, and this part of the heat is used for the raw material pretreatment device 7 to treat the dehydration, drying and other pretreatment of the domestic garbage raw materials. The moisture content of the pretreated garbage is less than 20%, which is conducive to increasing the temperature of the raw materials and the progress of cracking and gasification; the dried raw materials enter the upper moving bed 1 of the pyrolysis gasification furnace to participate in the first stage of pyrolysis and gasification; the above process can make full use of the heat and gas of the anoxic pyrolysis and gasification to prepare synthesis gas, and the in-situ combustion heat is used for the pretreatment of garbage raw materials, so as to realize full utilization of energy;

[0065] The liquid after the acid removal tower 4 absorbs the acid and water-soluble gas enters the water treatment unit 5 for treatment and then is discharged from the system.

[0066] Step 2: Preparation of high-quality hydrogen-rich syngas in the carbonization section

[0067] After water vapor and oxygen are injected into the lower moving bed 2, the second stage hydrogen-rich gas production reaction is carried out under micro-oxygen conditions. The obtained high-grade synthesis gas is passed through a CO2 removal reaction tower 8 to remove CO2. The obtained hydrogen-rich high-grade synthesis gas enters a high-grade gas collection device 9 for recovery, and the removed CO2 enters a CO2 recovery device 10 for recovery;

[0068] After the first stage of pyrolysis, the domestic waste is carbonized and has no other impurities. It enters the second stage of hydrogen-rich gas production with the unloading device at the lower end of the upper moving bed 1. In this stage, 2~15% O2 and 15%~30% water vapor are injected into the reaction area to create a micro-oxygen environment. The temperature of this stage is 600-800℃, so that it can maintain the temperature from the first stage without cooling, and the concentration of hydrogen-rich synthesis gas is as high as 90% or more (there are still a small amount of CO2 and water vapor). In this stage, by controlling the oxygen content and water content, the composition of the synthesis gas can be controlled to increase the H2 content in the synthesis gas. The equation is as follows: 2C+O2=2CO, CO+H2O=H2+CO2. The high-grade synthesis gas produced in this stage is mainly composed of H2 and CO2. After that, the CO2 by-product is removed by the CO2 removal reaction tower 8. The CO2 removal process includes but is not limited to pressure swing adsorption removal. After that, high-grade H2 and CO synthesis gas (containing more than 95% H2) is obtained, which can be directly prepared into finished fuel gas for various industrial purposes.

[0069] The 15% to 30% water vapor is prepared by heat exchange from the steam generated by the dehydration and drying pretreatment of the raw materials. Since the water vapor has been preheated and has a relatively high temperature, it not only maintains the steam state without condensation, but also has temperature, which can maintain the furnace temperature from dropping, and is also an energy-saving measure. The recovered preheated water vapor is returned to the water vapor required by the pre-oxidation section and the carbonization section of the upper moving bed or the lower moving bed, which not only does not affect the high efficiency of gas production, but also maintains the high quality of the synthesis gas and reduces the energy input.

[0070] Specifically, the heat generated by the combustion in the burner 6 enters the raw material pretreatment device 7 for dehydration and drying pretreatment of the raw material. A certain amount of water vapor containing heat will be generated during the dehydration and drying process of the pretreated raw material. The hot water vapor passes through the heat exchanger to condense the liquid into the water treatment unit 5 for treatment. Cold water is injected on the other side of the heat exchanger. Since the heat exchange itself generates water vapor, the water vapor, that is, 15% to 30% of the water vapor, can be used for water vapor injection of the upper moving bed or the lower moving bed. Therefore, the pretreatment device 7 not only does not discharge gas into the atmosphere, but its heat is used to generate 15% to 30% of water vapor, and the heat is also recovered.

[0071] The second stage is hydrogen-rich gas production. In this stage, 2-15% O2 (15% oxygen intake is used in this embodiment) and 15%-30% water vapor (30% water vapor is used in this embodiment) are injected into the reaction area. The presence of the water vapor H2O is used to produce a large amount of H2 and CO. 2-15% O2 not only accelerates the reaction, but also provides heat for the lower moving bed and maintains a constant temperature, thereby increasing the reaction rate of cracking and gasification.

[0072] Example 3

[0073] This embodiment uses the device of embodiment 1 to treat domestic organic waste:

[0074] The front end of this embodiment is exactly the same as that of Embodiment 2, and a conventional pressure swing adsorption process is then added to further process the high-grade gas; a hydrogen-rich high-grade synthesis gas containing 99% H2 is obtained, and the removed CO is returned to the carbonization section to prepare a hydrogen-rich high-grade synthesis gas, which then reacts with water vapor: CO+H2O=H2+CO2, to further generate H2.

[0075] In this embodiment: the second stage is hydrogen-rich gas production, in which 8% O2 and 20% water vapor are injected into the reaction area.

[0076] Example 4

[0077] This embodiment uses the device of embodiment 1 to treat domestic organic waste:

[0078] The front end of this embodiment is exactly the same as that of Embodiment 2, and the device further includes a slag collecting device 11; the collected slag is rich in K, Si, P, and C, and is used for the preparation of compound fertilizer. Specifically, the slag is collected, the stone and glass are removed, and it is ground and sieved. Organic carbon materials such as sawdust can be added in appropriate amounts to make compound fertilizers with different fertilizer content ratios and for different purposes. The slag after thermal cracking to remove hydrocarbons has porosity that is suitable for the growth of various organisms and microorganisms, and contains a certain amount of biomass carbon and P, and is rich in K and Si. It is a high-nutrition compound fertilizer for the growth of various plants. The urban organic domestic waste recycled by this process can be fully recycled.

[0079] In this embodiment: the second stage is hydrogen-rich gas production, in which 2% O2 and 15% water vapor are injected into the reaction area.

[0080] Comparative Example 1

[0081] This comparative example uses the method of treating domestic organic waste using the device of Example 1:

[0082] The front end of this comparative example is exactly the same as that of Example 2, except that: 1. the oxygen content of the lower moving bed 2 is changed.

[0083] When the oxygen content of the lower moving bed 2 is 50%, the local temperature of the inlet nozzle area exceeds 1500°C; the temperature of the upper moving bed 1 also rises to 600-800°C, and the outlet temperature of the low-grade synthesis gas is also about 600°C. It is found that the tar content at the electric decoking device 3 increases significantly;

[0084] The oxygen content of the lower moving bed 2 is adjusted to 15% or less, and the temperature of the air inlet nozzle area is easily controlled not to exceed 800°C; the outlet temperature of the low-grade syngas can also be controlled not to exceed 300°C, and the tar falls back into the upper moving bed tower due to condensation, thereby reducing the load of the electric decoking;

[0085] The oxygen content of the lower moving bed 2 is reduced by nearly 2%, and the slag collected by the slag collecting device 11 has a higher carbon content. The slag with high C content is suitable for making high-biochar compound fertilizer;

[0086] 2. The oxygen content continues to decrease. When the oxygen content is lower than 2%, it cannot meet the normal cracking of the slag in the lower moving bed 2. Therefore, the optimal oxygen intake of the lower moving bed during the preparation process is maintained at 2%-15%.

[0087] Experiments have shown that increasing the oxygen content or too low an oxygen content is not conducive to optimizing the product quality of the thermal cracking gasification process.

[0088] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A device for producing high-grade hydrogen-rich syngas by pyrolyzing urban organic waste, characterized in that: The device comprises: a reaction tower, wherein the reaction tower comprises an upper moving bed (1) and a lower moving bed (2), and the raw materials carbonized in the upper moving bed (1) enter the lower moving bed (2) for reaction; The upper moving bed (1) is connected in sequence to an electric decoking device (3) and a deacidification tower (4); the electric decoking device (3) is used to remove tar, and the deacidification tower (4) is used to spray and remove acidic and water-soluble gases; the deacidification tower (4) is connected to a burner (6); the heat generated by the combustion of gas in the burner (6) enters a raw material pretreatment device (7) for dehydration and drying pretreatment of the raw material; the pretreated raw material enters the upper moving bed (1) through a feed for a preoxidation section, and the raw material after the preoxidation section enters the lower moving bed (2); The lower moving bed (2) is connected to a CO2 removal reaction tower (8), the removed CO2 enters a CO2 recovery device (10) for recovery, and the gas from which CO2 has been removed enters a high-grade gas collection device (9) for recovery; The lower moving bed (2) is 60%-80% of the diameter of the upper moving bed (1); The bottoms of the upper moving bed (1) and the lower moving bed (2) are both provided with a material discharge device; The material feeding device is provided with fins (14) for material feeding and stirring and a nozzle with a roller (15) for heating the material; the multi-layer stirring fins and the nozzle with a roller form an automatic mechanical stirring device; The fins (14) are inclined at an angle of 30 to 60 degrees; each layer of the unloading device is provided with 3 to 5 fins (14); the fins (14) are grouped into a layer consisting of three to five fins, and the multi-layer assembly device is placed in the tower and arranged along the tower wall; The roller nozzle (15) is placed at the lower edge of the fin (14); the nozzle (15) actively rotates in the same direction; the rotation of the nozzle further pulls the material downward.

2. The device for producing high-grade hydrogen-rich syngas by pyrolyzing urban organic waste according to claim 1, characterized in that: The device is also provided with a low-grade synthesis gas outlet (12) and a high-grade synthesis gas outlet (13), wherein the low-grade synthesis gas outlet (12) is located at the upper end of the upper moving bed (1) and is used for the low-grade synthesis gas to enter the electric decoking device (3) from the upper moving bed (1); and the high-grade synthesis gas outlet (13) is located at the upper end of the lower moving bed (2) and is used for the high-grade synthesis gas to enter the CO2 removal reaction tower (8) from the lower moving bed (2).

3. The device for producing high-grade hydrogen-rich syngas by pyrolyzing urban organic waste according to claim 1, characterized in that: The device also includes a slag collecting device (11) for collecting slag.

4. A method for producing high-grade hydrogen-rich syngas by pyrolyzing urban organic waste, characterized in that: The method is to utilize the device for producing high-grade hydrogen-rich synthesis gas by pyrolyzing urban organic waste as described in claim 1, comprising: Step 1: Pre-oxidation of raw materials The raw material pre-treated by dehydration and drying in the raw material pre-treatment device (7) is fed into the upper moving bed (1) and then subjected to the first stage of anoxic pyrolysis and gasification at a medium-low temperature. The low-grade synthesis gas produced is passed through the low-grade synthesis gas outlet (12) and sequentially passed through the electric decoking device (3) to remove tar, and passed through the deacidification tower (4) to remove acid and water-soluble gases, and then enters the burner (6) for combustion. The heat after combustion enters the raw material pre-treatment device (7) for dehydration and drying pre-treatment of the raw material. The raw material produced by the pyrolysis and gasification in the upper moving bed (1) is passed down through the unloading device and enters the lower moving bed (2) for further reaction. Step 2: Preparation of high-quality hydrogen-rich syngas in the carbonization section After water vapor and oxygen are injected into the lower moving bed (2), the second stage hydrogen-rich gas production reaction is carried out under a micro-oxygen condition. The obtained high-grade synthesis gas is passed through a CO2 removal reaction tower (8) to remove CO2, and the obtained hydrogen-rich high-grade synthesis gas enters a high-grade gas collection device (9) for recovery.

5. The method for producing high-grade hydrogen-rich synthesis gas by pyrolyzing urban organic waste according to claim 4, characterized in that: In the step 1, the temperature of the first stage of anaerobic pyrolysis and gasification at medium and low temperature is a gradient temperature; specifically, the temperature of the combustion aid inlet, i.e., the flare outlet, is 400-600°C, and the temperature of the synthesis gas outlet, i.e., the tower outlet end, is 200-300°C.

6. The method for producing high-grade hydrogen-rich synthesis gas by pyrolyzing urban organic waste according to claim 4, characterized in that: In the step 2, the reaction temperature of the second stage hydrogen-rich gas production reaction is 600-800°C.

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