Solid waste treatment system and method based on gasification slag smoldering and organic solid waste pyrolysis

Abstract

The application discloses a solid waste treatment system and method based on gasification slag smoldering and organic solid waste pyrolysis, and belongs to the technical field of solid waste treatment. The system comprises a first reaction furnace and a second reaction furnace. The feeding mechanism, smoke outlet, heating mechanism and gas supply mechanism of the two reaction furnaces are combined and arranged. The condensing mechanism, flow distribution valve and gas purification / mixing device work cooperatively, and heat is transferred between the two reaction furnaces. The smoldering treatment of gasification slag and the pyrolysis treatment of carbon-rich organic solid waste can be accurately completed. The solid waste treatment system has simple system composition and convenient control. The high-value recycling of gasification slag and carbon-rich organic solid waste can be realized without using a large amount of external auxiliary energy. Low-oxygen CO-rich gas and pyrolysis semi-coke can be quickly prepared. The recycling rate of the available energy in the gasification slag and carbon-rich organic solid waste is improved. The treatment cost of the gasification slag and carbon-rich organic solid waste is reduced. The system has good economic value and practical value.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of solid waste treatment, and particularly relates to a solid waste treatment system and method based on gasification slag smoldering and organic solid waste pyrolysis. BACKGROUND

[0002] Coal gasification is a core technology for clean and efficient utilization of coal, and is widely used in steel, machinery, chemical industry, building materials and other fields. In the process of coal gasification, gasification coarse slag is often directly discharged from the bottom of the furnace, and its composition is similar to that of boiler ash, with low carbon content, which can be used as a mixed raw material for road building or backfilling. However, due to its high carbon content and high loss on ignition, gasification fine slag does not meet the national and industry standards for building mixed raw materials and is difficult to be directly used in construction and road engineering. There is a lack of effective and large-scale disposal methods, and it is often disposed of by stacking or landfilling. However, the landfilling or stacking of high-carbon gasification fine slag results in serious resource waste, occupies a large amount of land resources, causes air pollution due to dust, and pollutes soil and water after long-term stacking or landfilling.

[0003] Therefore, how to effectively utilize gasification slag has become the focus of researchers. The large-scale disposal of gasification fine slag using a reasonable and effective method not only reduces its impact on the environment, but also recovers energy from it, thereby ensuring the sustainable development of coal chemical enterprises. Currently, the energy recovery from gasification slag usually uses a combustion method. This method mainly targets gasification fine slag, which can utilize the energy of gasification fine slag. However, in order to maintain the stable operation of the combustion equipment, only a low proportion of gasification fine slag can be mixed and burned. Due to its high water content, the combustion process is often unstable, and a large amount of additional fuel or heat is often added for pre-drying or mixed burning. The equipment system is complex, the energy consumption and economic investment cost are high, and the economic efficiency is extremely poor.

[0004] In addition, with the rapid development of China's social economy, the amount of solid waste is increasing year by year. The annual production of organic solid waste, such as living sources (domestic waste, kitchen waste, and municipal sludge), agricultural sources (agricultural and forestry straw, livestock and poultry manure), and industrial sources (oily sludge, waste rubber, and fungus residue), accounts for more than 60% of the total amount of solid waste and needs to be disposed of. However, the treatment capacity of traditional treatment methods is limited, and they cannot effectively achieve large-scale disposal, which puts great pressure on environmental protection. SUMMARY

[0005] In view of one or more of the above defects or improvement needs of the prior art, the present application provides a solid waste treatment system and method based on gasification slag smoldering and organic solid waste pyrolysis, which can realize the collaborative treatment of gasification slag and carbon-rich organic solid waste, and simultaneously prepare high-concentration CO gas and high-calorific-value pyrolysis semicoke, thereby realizing the gradient high-value utilization of gasification slag and organic solid waste.

[0006] To achieve the above object, one aspect of the present application provides a solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis, which comprises:

[0007] a first reaction furnace, which is a smoldering furnace, and is provided at the top thereof with a first flue gas outlet for discharging first flue gas generated after the gasification slag smolders and a first feeding mechanism for feeding smoldering reaction mixture, and is provided at the bottom thereof with a first gas supply mechanism for supplying gas required for smoldering reaction and a first heating mechanism for heating the material at the bottom of the furnace;

[0008] a second reaction furnace, which is embedded in the first reaction furnace and extends from the bottom to the top of the first reaction furnace; the top of the second reaction furnace is provided with a second flue gas outlet and a second feeding mechanism for discharging second flue gas generated by pyrolysis reaction and feeding pyrolysis reaction mixture, respectively; and the bottom of the second reaction furnace is provided with a second gas supply mechanism and a second heating mechanism; and the wall of the second reaction furnace is made of a material with good heat conduction performance, so that the heat generated by the smoldering reaction in the first reaction furnace can be transferred to the second reaction furnace;

[0009] a condensing mechanism, which is in communication with the first flue gas outlet and the second flue gas outlet through pipes, respectively, for condensing the first flue gas and the second flue gas; and a flow distribution valve is provided corresponding to the condensed first flue gas, the inlet end of which is in communication with the condensing mechanism for outputting the condensed first flue gas in proportion, so that part of the first flue gas is sent into the second reaction furnace through the second gas supply mechanism, and the remaining first flue gas is transported to a gas purification / mixing device through a pipe;

[0010] a gas purification / mixing device, which is in communication with the condensing mechanism for condensing the second flue gas and the flow distribution valve through pipes, respectively, for purifying and mixing the two condensed flue gases to obtain rich-burning fuel gas.

[0011] As a further improvement of the present application, a plurality of thermocouples are arranged along the axis and spaced apart in the first reaction furnace and the second reaction furnace, respectively, for real-time monitoring of the reaction temperature at different positions of the reaction furnace.

[0012] As a further improvement of the present application, the bottom of each of the two reaction furnaces is provided with a slag discharge port, and a slag discharging mechanism is provided corresponding to each of the two slag discharge ports.

[0013] As a further improvement of the present application, the second flue gas outlet is an annular gas outlet arranged between the first feeding mechanism and the second feeding mechanism;

[0014] and / or

[0015] At least one feeding mechanism is a screw feeding mechanism.

[0016] Another aspect of the present application also provides a solid waste treatment method based on gasification slag smoldering and organic solid waste pyrolysis, which is realized by using a solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis, and includes the following processes:

[0017] (1) preparing smoldering reaction mixture and pyrolysis reaction mixture;

[0018] The gasification slag is mixed with inert medium to prepare the smoldering reaction mixture, and the mass ratio of the two is in the range of 1:1-1:6, and the water content of the gasification slag is controlled in the range of 10%-80%; the carbon-rich organic solid waste is mixed with inert medium to prepare the pyrolysis reaction mixture, and the mass ratio of the two is in the range of 1:0.5-1:8;

[0019] (2) filling the two mixtures into the corresponding reaction furnaces respectively until the corresponding reaction furnaces are filled;

[0020] (3) starting the heating mechanism at the bottom of the first reaction furnace, preheating the mixture at the bottom of the first reaction furnace to the ignition temperature, and then stopping heating;

[0021] (4) introducing reaction gas into the bottom of the first reaction furnace through the first gas supply mechanism and igniting, starting the smoldering reaction of the mixture in the first reaction furnace, and sequentially forming a high-temperature high-oxygen oxidation zone, a high-temperature low-oxygen gasification zone, a medium-temperature low-oxygen pyrolysis zone and a low-temperature low-oxygen drying zone in the first reaction from bottom to top, respectively completing the high-temperature oxidation process, the high-temperature gasification process, the pyrolysis process and the drying process of the smoldering reaction mixture, and obtaining the first flue gas which is discharged from the first flue gas outlet;

[0022] The gas velocity of the reaction gas is controlled in the range of 1 cm / s-15 cm / s, the oxygen concentration in the reaction gas is 10%-30%, the core reaction temperature in the high-temperature high-oxygen oxidation zone is not less than 900℃, and the oxygen concentration at the end of the high-temperature high-oxygen oxidation zone is controlled in the range of 2%-6%; the gasification reaction temperature in the high-temperature low-oxygen gasification zone is controlled above 800℃, and the oxygen concentration at the end of the high-temperature low-oxygen gasification zone is controlled below 1%;

[0023] (5) introducing at least part of the condensed first flue gas into the bottom of the second reaction furnace through the second gas supply mechanism, and controlling the flow distribution valve to adjust the flow of the condensed first flue gas introduced by the second gas supply mechanism, adjusting the temperature of the pyrolysis reaction in the second reaction furnace by controlling the flow, forming a low-oxygen / no-oxygen pyrolysis zone with a temperature range of 400-600℃, continuously completing the pyrolysis reaction of the carbon-rich organic solid waste, and discharging the second flue gas from the second flue gas outlet;

[0024] (6) The condensed second flue gas and the condensed first flue gas not passing through the second reaction furnace are introduced into the gas purification / mixing device, and finally, the rich combustion gas is obtained and output.

[0025] As a further improvement of the present application, in process (1), the gasification slag is a gasification coarse slag with a water content of less than 30%, and the mass ratio of the gasification coarse slag and the inert medium ranges from 1:1 to 1:3 when mixed.

[0026] Or

[0027] The gasification slag is a gasification fine slag with a water content of more than 30%, and the mass ratio of the gasification fine slag and the inert medium ranges from 1:2 to 1:5 when mixed.

[0028] As a further improvement of the present application, in process (2), before the feeding and filling of the two mixed materials, a certain thickness of preheated filler is filled at the bottom of the two reaction furnaces, so that the preheated filler covers the heating mechanism at the bottom of the two reaction furnaces.

[0029] As a further improvement of the present application, in process (3), the preheating temperature of the mixed material is 250-400°C.

[0030] As a further improvement of the present application, in process (4), the reaction gas sent into the first reaction furnace is mixed with CO2 with a concentration ranging from 0 to 85%.

[0031] As a further improvement of the present application, in process (6), the waste slag discharged from the bottom of the second reaction furnace is screened to obtain high-calorific-value pyrolysis semi-coke.

[0032] The above technical features can be combined with each other as long as they do not conflict with each other.

[0033] Overall, compared with the prior art, the above technical scheme conceived by the present application has the following beneficial effects:

[0034] (1) The solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis in the present application includes a first reaction furnace and a second reaction furnace. By combining the feeding mechanism, the smoke outlet, the heating mechanism and the gas supply mechanism on the two reaction furnaces, cooperating with the condensing mechanism, the flow distribution valve and the gas purification / mixing device, and the heat transfer between the two reaction furnaces, the smoldering treatment of the gasification slag and the pyrolysis treatment of the carbon-rich organic solid waste can be accurately completed, thereby obtaining the rich combustion gas rich in CO and the high-calorific-value pyrolysis semi-coke, so as to realize the efficient utilization and harmless treatment of the gasification slag and the carbon-rich organic solid waste, effectively improve the energy utilization efficiency of the solid waste resources, and avoid the waste of resources.

[0035] (2) The solid waste treatment method based on gasification slag smoldering and organic solid waste pyrolysis has simple treatment process, convenient control, can accurately complete the smoldering treatment process of the gasification slag and the oxygen-free / low-oxygen pyrolysis process of the carbon-rich organic solid waste, and quickly realizes the preparation of the first flue gas and the second flue gas rich in CO; meanwhile, by introducing the condensed first flue gas into the second reaction furnace and accurately controlling the flow rate, the accurate control of the pyrolysis reaction in the second reaction furnace can be realized, the control process of the two reaction furnaces in the system is simplified, the content of nitrogen oxides in the final flue gas is effectively reduced, the cleanliness of the mixed flue gas is ensured, and finally the carbon-rich combustion gas rich in CO can be obtained, so that the recovery treatment of the gasification slag and the carbon-rich organic solid waste is efficiently completed, and the energy utilization rate of the solid waste is improved.

[0036] (3) The solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis further strengthens the gasification reaction of carbon in the gasification slag by mixing a certain concentration of CO2 gas in the gas introduced into the first reaction furnace, so as to further improve the gasification effect and the CO concentration in the outlet flue gas, and improve the quality of the prepared fuel gas.

[0037] (4) The solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis has simple system composition and convenient control, can realize the high-value recycling of the gasification slag and the carbon-rich organic solid waste without using a large amount of external auxiliary energy, realize the rapid preparation of the low-oxygen carbon-rich flue gas and the pyrolysis semicoke, improve the recycling rate of the internal available energy of the gasification slag and the carbon-rich organic solid waste, reduce the treatment cost of the gasification slag and the carbon-rich organic solid waste, and has good economic value and practical value. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0039] Figure 1 is a schematic diagram of the solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis in the embodiments of the present application. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as there is no conflict.

[0041] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0042] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0043] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0045] Embodiment:

[0046] Please refer to Figure 1The solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis in the preferred embodiment of the present application comprises a first reaction furnace for gasification slag smoldering and a second reaction furnace embedded in the first reaction furnace, a pyrolysis reaction chamber for carbon-rich organic solid waste pyrolysis is formed in the second reaction furnace, and a smoldering reaction chamber for gasification slag smoldering is formed between the outer wall of the second reaction furnace and the inner wall of the first reaction furnace.

[0047] Specifically, the first reaction furnace is a smoldering furnace in a cylindrical structure, and a first feeding mechanism for feeding smoldering materials and a first flue gas outlet for discharging flue gas (i.e. first flue gas) generated after smoldering are arranged at the top of the first reaction furnace; correspondingly, a first slag discharge port for discharging smoldering waste slag is formed at the bottom of the first reaction furnace.

[0048] Meanwhile, the second reaction furnace is in a cylindrical structure, and the furnace wall is made of a material with good heat conduction performance (such as steel), which extends from the bottom of the first reaction furnace to the top of the first reaction furnace, and a second feeding mechanism for feeding pyrolysis materials and a second flue gas outlet for discharging flue gas (i.e. second flue gas) generated after pyrolysis reaction are formed at the top of the second reaction furnace. In the preferred embodiment, the second flue gas outlet is an annular flue gas outlet arranged outside the second feeding mechanism. In actual work, the second flue gas in the second reaction furnace moves from bottom to top, which can heat the pipe wall of the second feeding mechanism, thereby realizing the preheating of the material fed in the second reaction furnace.

[0049] Correspondingly, the first feeding mechanism is preferably arranged outside the periphery of the bottom of the second reaction furnace, and the second flue gas outlet is an annular gas outlet arranged between the first feeding mechanism and the second feeding mechanism. In this way, the flue gas in the second flue gas outlet can heat the materials fed in the two feeding mechanisms.

[0050] In actual setting, both feeding mechanisms are preferably spiral feeding mechanisms for continuous feeding of gasification slag mixed materials and carbon-rich organic solid waste materials.

[0051] In addition, a second slag discharge port for discharging pyrolysis waste slag is also preferably arranged at the bottom of the second reaction furnace, and a slag discharge mechanism is preferably arranged at the first slag discharge port and the second slag discharge port, respectively.

[0052] Further, a heating mechanism, i.e. a first heating mechanism and a second heating mechanism, is arranged at the bottom of the first reaction furnace and the second reaction furnace, respectively. In the preferred embodiment, both heating mechanisms are preferably heating rods for preheating the materials at the bottom of the two reaction furnaces to a corresponding temperature.

[0053] In detail, a first gas supply mechanism is arranged at the bottom of the first reactor for supplying reaction gas to the bottom of the first reactor to meet the reaction. Meanwhile, a condensing mechanism is arranged at the exhaust port of the top of the two reactors, which is communicated with the two exhaust ports through pipelines, so that the flue gas discharged from the two exhaust ports can enter the condensing mechanism through the pipelines and complete the condensation and water removal process of the fuel-rich flue gas.

[0054] In actual arrangement, the two exhaust ports can be communicated with different inlets of the same condensing mechanism and discharged from different outlets. Of course, according to the actual arrangement needs, the condensing mechanism can also be arranged for the two exhaust ports respectively, which will not be described here.

[0055] Further, a gas purification / mixing device is arranged, which is communicated with the condensing mechanism through two pipelines, for purifying and mixing the two fuel-rich flue gases after condensation, and finally obtaining the mixed fuel-rich gas.

[0056] Considering that the pyrolysis reaction process in the second reactor is in an oxygen-free reducing atmosphere, which can reduce the nitrogen oxides in the first flue gas, reduce the pollutants in the first flue gas, and improve the cleanliness of the first flue gas. Therefore, in the preferred embodiment, a flow distribution valve is further arranged on the conveying pipeline of the condensed first flue gas, and a second gas supply mechanism is arranged corresponding to the second reactor, so that part of the condensed first flue gas can be conveyed to the second reactor through the second gas supply mechanism, mixed with the second flue gas generated by pyrolysis after reduction treatment, and then discharged.

[0057] By changing the opening of the flow distribution valve to pass different flow of the condensed first flue gas into the second reactor, not only the reduction of nitrogen oxides in the first flue gas can be completed, but also the internal maximum temperature of the carbon-rich organic solid waste material in the second reactor can be maintained at a relatively stable level. Specifically, when the internal temperature of the carbon-rich organic solid waste material is high, the flow of the flow distribution valve into the second reactor is increased; and when the internal temperature of the carbon-rich organic solid waste material is low, the flow of the flow distribution valve into the second reactor is reduced.

[0058] Preferably, in actual work, the flow communicated with the second reactor accounts for 30%~60% of the total flow of the first flue gas, and the flow communicated with the gas purification / mixing device accounts for 40%~70% of the total flow of the condensed first flue gas.

[0059] Further specifically, in order to realize the accurate adjustment of the corresponding control conditions in the two reactors, a plurality of thermocouples are preferably arranged in the two reactors along the vertical direction in sequence to monitor the reaction temperature at different positions of the reactor, which provides the basis for the adjustment of the corresponding control conditions.

[0060] In addition, a slag discharging mechanism is arranged at the bottom of each of the two reaction furnaces, which is used to screen the waste discharged from the bottom of the reaction furnace, and quartz sand, gasification slag ash, pyrolysis semi-coke and the like are obtained through screening, wherein the quartz sand can be recycled, and the pyrolysis semi-coke can be recycled as high-calorific-value fuel.

[0061] By using the combination of the solid waste treatment system, the smoldering treatment process of the gasification slag and the pyrolysis treatment process of the carbon-rich organic solid waste can be effectively realized. Based on the cooperation of the oxidation, gasification and pyrolysis processes of the gasification slag in the smoldering furnace, the preparation of CO-rich fuel gas can be realized. At the same time, based on the heat generated in the smoldering process of the gasification slag, the pyrolysis reaction process of the carbon-rich organic solid waste can be realized, and the preparation of fuel-rich pyrolysis flue gas and high-calorific-value pyrolysis semi-coke can be realized, so as to fully realize the recycling of the available energy in the gasification slag and the carbon-rich organic solid waste, and complete the gradient high-value utilization of the gasification slag and the organic solid waste.

[0062] In actual setting, the preparation method of the fuel-rich fuel gas and the high-calorific-value pyrolysis semi-coke by using the solid waste treatment system preferably includes the following processes:

[0063] (1) Preparation of smoldering reaction mixture and pyrolysis reaction mixture;

[0064] In actual operation, the gasification slag and the inert medium are preferably uniformly mixed in a certain proportion to form the smoldering reaction mixture with porous characteristics. At the same time, the carbon-rich organic solid waste and the inert medium are uniformly mixed in a certain proportion to form the pyrolysis reaction mixture with porous characteristics.

[0065] In the preferred embodiment, the gasification slag is preferably gasification fine slag or gasification coarse slag, and the water content thereof is preferably controlled to be between 10% and 80%. The gasification coarse slag is the water-containing slag discharged from the slag lock hopper at the bottom of the gasification furnace through the processes of melting, quenching and condensation of slurried coal particles under high temperature and high pressure in the gasification furnace, and the residual carbon content fluctuates greatly with the coal type, the type of gasification furnace and the operating conditions of the gasification furnace, and is generally between 10% and 30%, and the particle size is concentrated between 16 mesh and 4 mesh. The gasification fine slag is the water-containing slag obtained by preliminary washing and purification and sedimentation from the coarse coal gas stream carried out from the top of the gasification furnace, and the residual carbon content is relatively high, generally more than 30%, and the particle size is less than 16 mesh, of which about one-third is less than 200 mesh.

[0066] At the same time, the water content of the carbon-rich organic solid waste in the preferred embodiment is preferably between 0% and 50%, and the particle size after crushing is controlled to be less than 1 mm.

[0067] At the same time, the inert medium mixed with the gasification slag in the preferred embodiment is preferably the same as the inert medium mixed with the carbon-rich organic solid waste, which is further preferably quartz sand or sand with a particle size of 1-3 mm, and the water content thereof is preferably controlled to be less than 20% when used in mixing.

[0068] More specifically, in the preferred embodiment, the mass ratio of the gasification slag to the inert medium is preferably in the range of 1:1 to 1:6, and the specific ratio is preferably determined by the particle size characteristics of the gasification slag (mainly determined by the moisture content and the calorific value). When the gasification slag is fine slag, the moisture content is usually above 30%, and the mass ratio of the fine slag to the inert medium is preferably controlled in the range of 1:2 to 1:5. Correspondingly, when the gasification slag is coarse slag, the moisture content is below 30%, and the optimal mass ratio of the coarse slag to the inert medium is preferably controlled in the range of 1:1 to 1:3.

[0069] Meanwhile, the mass ratio of the carbon-rich organic solid waste to the inert medium is preferably in the range of 1:0.5 to 1:8.

[0070] (2) Perform the filling operation of the mixture in the corresponding reaction furnace;

[0071] Specifically, the smoldering reaction mixture is fed into the first reaction furnace through the first feeding mechanism, and the carbon-rich organic solid waste is fed into the second reaction furnace through the second feeding mechanism.

[0072] In the preferred embodiment, before feeding the two mixture materials, a certain thickness of preheated filler is preferably filled into the bottom of the two reaction furnaces through the two feeding mechanisms. In the preferred embodiment, the preheated filler is preferably large-particle quartz sand, the particle size is preferably 5mm to 8mm, and the filling thickness preferably ensures that the heating mechanism at the bottom of the corresponding reaction furnace can be covered.

[0073] (3) Turn on the heating mechanism at the bottom of the first reaction furnace to preheat the mixture at the bottom of the reaction furnace, and stop heating when the temperature of the lowermost layer of material reaches the ignition temperature;

[0074] In the preferred embodiment, the preheating temperature (ignition temperature) of the mixture is preferably 250°C to 400°C, and further preferably 300°C.

[0075] (4) Feed the reaction gas into the bottom of the first reaction furnace through the gas supply mechanism and ignite it to start the smoldering reaction of the smoldering reaction mixture with porous properties, and sequentially form a high-temperature high-oxygen oxidation zone, a high-temperature low-oxygen gasification zone, a medium-temperature low-oxygen pyrolysis zone, a low-temperature low-oxygen drying zone, and a fresh mixture replenishment zone in the first reaction furnace from bottom to top.

[0076] Specifically, during the smoldering reaction, the mixture at the lower layer of the smoldering reaction device performs oxidation reaction in a high-oxygen environment with a core reaction temperature not lower than 900°C, forming a high-temperature high-oxygen oxidation zone, and generating high-temperature low-oxygen high-concentration CO2 flue gas, which is referred to as initial flue gas. The temperature of the initial flue gas is not lower than 850°C, and the oxygen concentration therein is between 4% and 6%.

[0077] In the high-temperature high-oxygen oxidation zone, the oxidation reaction of the mixture is as follows:

[0078] C + O2→ CO2(1)

[0079] To ensure the accuracy of the oxidation reaction in the high-temperature high-oxygen oxidation zone, the oxygen concentration of the initial section of the high-temperature high-oxygen oxidation zone is controlled to be above 15% and the oxygen concentration of the end section of the high-temperature high-oxygen oxidation zone is controlled to be between 2% and 6% when the reaction conditions are actually controlled. Further preferably, the oxygen concentration of the initial section is controlled to be between 15% and 30%. Meanwhile, the highest temperature of the core reaction zone in the high-temperature high-oxygen oxidation zone is preferably controlled to be above 900°C.

[0080] For the above control conditions, if the oxygen concentration of the initial section is too low, the oxidation exothermic reaction intensity in reaction (1) will be relatively weak, the reaction temperature exothermic will not be enough to produce a high-temperature environment above 900°C, resulting in a relatively weak subsequent gasification reaction and a low CO concentration, which cannot achieve the purpose of producing CO-rich fuel gas. Meanwhile, if the oxygen concentration of the end section is too high, the carbon in the gasification slag in the high-temperature low-oxygen gasification zone will rapidly undergo a combustion reaction, and the combustion reaction (i.e., the above oxidation reaction (1)) will be significantly stronger than the expected gasification reaction, resulting in a relatively low CO concentration in the flue gas, which cannot achieve the purpose of producing CO-rich fuel gas.

[0081] To achieve the above purpose, in actual operation, the oxygen content of the gas sent into the smoldering reaction device is preferably controlled to be between 15% and 30%, and the gas velocity is controlled to be between 1 cm / s and 10 cm / s; correspondingly, the reaction temperature in the high-temperature high-oxygen oxidation zone is maintained at 900-1100°C. For the adjustment of this reaction temperature, the oxygen concentration in the gas sent can be changed, which is not described here.

[0082] Further, after the initial flue gas flows upward to the upper layer of the adjacent dry material, the CO2 in the flue gas and the carbon in the gasification slag undergo a gasification reaction in a high-temperature low-oxygen environment, the temperature of this gasification reaction is above 800°C, and a high-temperature low-oxygen flue gas rich in CO gas is generated.

[0083] In the high-temperature low-oxygen gasification zone, the gasification reaction of the mixture with the initial flue gas is as follows:

[0084] C + CO2→ 2CO (2)

[0085] In the high-temperature low-oxygen gasification zone, the core reaction temperature is above 800℃. In the initial section of the high-temperature low-oxygen gasification zone (close to the side of the high-temperature high-oxygen oxidation zone), the oxygen concentration is relatively high, at 2%~6%; at this time, the reaction temperature of the initial section of the high-temperature low-oxygen gasification zone is preferably controlled to be above 850℃. Correspondingly, after the gasification reaction in the gasification zone, the oxygen in the flue gas is further consumed, and in the high-temperature low-oxygen flue gas formed in the end section of the high-temperature low-oxygen gasification zone, the oxygen concentration is below 1%, and this flue gas is referred to as intermediate flue gas.

[0086] In the high-temperature low-oxygen gasification zone, competition between the above-mentioned reactions (1) and (2) will occur, if the oxygen concentration in this zone is too high and the temperature is below the gasification reaction temperature, the oxidation reaction (1) will be significantly stronger than the gasification reaction (2), resulting in a low CO concentration in the intermediate flue gas at the end section of the high-temperature low-oxygen gasification zone, which cannot achieve the purpose of producing CO-rich fuel gas; in addition, if the oxygen concentration at the end section of the high-temperature low-oxygen gasification zone is too high, part of the volatile gas generated in the pyrolysis zone in the next stage will rapidly combust with oxygen, thereby reducing the concentration of combustible gas in the flue gas and causing part of the carbon in the gasification slag to be consumed in this stage, thereby reducing the carbon content involved in the reactions in the high-temperature high-oxygen oxidation zone and the high-temperature low-oxygen gasification zone, affecting the heat release in the oxidation zone and the gasification effect in the gasification zone.

[0087] After passing through the high-temperature low-oxygen gasification zone, the oxygen concentration in the flue gas (intermediate flue gas) is further reduced, but the flue gas temperature still remains in a relatively high range (500~800℃), thereafter, as the flue gas further flows upward in the smoldering reaction device, a medium-temperature low-oxygen pyrolysis zone is formed above the high-temperature low-oxygen gasification zone, and through the mutual contact and action of the intermediate flue gas and the mixed material in the pyrolysis zone, part of the volatile in the gasification slag is released and enters the flue gas, obtaining tail-end flue gas with further increased combustible gas content, at this time, the temperature of the tail-end flue gas has been reduced to below 200℃.

[0088] In actual operation, since the flue gas is in a high-CO and low-oxygen state, the concentration of pollutants such as nitrogen oxides in the flue gas can always be maintained at a relatively low level.

[0089] Further, after passing through the pyrolysis zone, the tail-end flue gas further flows upward and contacts with the fresh mixed material supplemented from above, and the fresh mixed material is dried by the residual heat of the tail-end flue gas, forming a low-temperature low-oxygen drying zone with a certain thickness inside the smoldering reaction device, and obtaining a final CO-rich first flue gas containing moisture. In the preferred embodiment, the CO concentration in the finally derived first flue gas is not less than 10%, and the oxygen concentration therein is less than 1%.

[0090] (5) The flue gas discharged from the two rows of smoke outlets is respectively transported to the condensing mechanism for condensation, and at least part of the condensed first flue gas is introduced into the second reaction furnace as needed, and the remaining first flue gas and the condensed second flue gas are mixed in the gas purification / mixing device, thereby obtaining a rich-burning fuel gas rich in CO.

[0091] Specifically, due to the smoldering reaction of the mixed material in the first reaction furnace, a high-temperature reaction section with a certain height (corresponding to a high-temperature high-oxygen oxidation zone, a high-temperature low-oxygen gasification zone, and a medium-temperature low-oxygen pyrolysis zone) is formed in the first reaction furnace, and due to heat transfer, a low-oxygen / zero-oxygen pyrolysis zone with a certain height is formed in the second reaction furnace, as shown in Figure 1 The pyrolysis reaction of the pyrolysis reaction mixture is started.

[0092] In actual operation, the temperature in the low-oxygen / zero-oxygen pyrolysis zone is preferably controlled at 400-600°C. According to the foregoing description, in actual operation, the temperature in the low-oxygen / zero-oxygen pyrolysis zone can be adjusted by adjusting the flow distribution valve to distribute the flow of the first flue gas introduced into the second reaction furnace.

[0093] Correspondingly, the first flue gas passing through the low-oxygen / zero-oxygen pyrolysis zone is heated by heat absorption and mixed with the flue gas generated by the pyrolysis reaction of the pyrolysis reaction mixture, and continues to flow upward, and the mixed flue gas dries the pyrolysis reaction mixture fed into the second reaction furnace, forming a material drying zone with a certain height at the top of the second reaction furnace. Thereafter, the mixed flue gas containing moisture is discharged from the second smoke outlet, and the concentration of combustible substances in the mixed flue gas is further increased compared to the first flue gas introduced into the second reaction furnace.

[0094] For the method in the preferred embodiment, by adjusting the mixing ratio between the gasification slag and the inert medium, the gas flow rate to the smoldering reaction device, and the oxygen concentration in the gas, the core reaction temperature in the high-temperature high-oxygen oxidation zone of the first reaction furnace can be effectively controlled to be not less than 900°C, and the CO concentration in the obtained flue gas can be ensured to be not less than 10%. At the same time, by preferably controlling the flow of the condensed first flue gas introduced into the second reaction furnace, the pyrolysis reaction temperature in the second reaction furnace can be accurately controlled, the pyrolysis treatment of the carbon-rich organic solid waste can be completed, and low-oxygen rich-burning pyrolysis flue gas and pyrolysis semi-coke can be obtained, thereby reliably realizing the recycling treatment of the carbon-rich organic solid waste.

[0095] In addition, by screening the waste slag discharged from the bottom of the second reaction furnace, high-calorific-value pyrolysis semi-coke can be further obtained.

[0096] More specifically, in order to improve the gasification effect in the high-temperature low-oxygen gasification zone of the first reaction furnace and increase the CO concentration in the outlet flue gas, a certain concentration of CO2 gas is preferably mixed into the gas fed into the smoldering reaction device, and the mixing concentration is preferably 0-85%, and further preferably 30%.

[0097] For the existing gasification slag treatment method, because the gasification slag contains water, a large amount of energy needs to be consumed for drying in the thermal treatment process (such as incineration), while the gasification slag has a relatively low heat value and poor stable combustion effect, resulting in a very low resource utilization efficiency.

[0098] In comparison, in the technical solution of the foregoing preferred embodiment, by combining the dehydration, pyrolysis, gasification and oxidation processes of the gasification slag with the smoldering treatment technology, using the heat generated by the smoldering reaction of the gasification slag as a heat source, the water in the gasification slag is removed and dried, without the need for external auxiliary energy to dry the gasification slag, so that a self-sustaining reaction can be achieved, and the energy consumption is low. Moreover, by optimizing the design of the corresponding control conditions, the formation of the corresponding regions in the smoldering reaction device can be completed, high-concentration CO can be prepared from the gasification slag, high-quality fuel gas can be obtained, and the harmless treatment and energy recovery of the gasification slag can be fully achieved.

[0099] Meanwhile, by using the heat generated by the smoldering reaction of the gasification slag and the corresponding arrangement of the second reaction furnace in the first reaction furnace, the smoldering reaction in the first reaction furnace can be accurately carried out in the second reaction furnace at the same time, further improving the concentration of combustible gas in the recovered flue gas, increasing the quality and heat value of the final obtained rich-burning fuel gas. In addition, high-heat-value pyrolysis semi-coke can also be recovered by the pyrolysis reaction of the carbon-rich organic solid waste, achieving the harmless treatment and energy recovery of the carbon-rich organic solid waste.

[0100] In order to further supplement the advantages and technical effects of the technical solution in the preferred embodiment of the present application, the following specific embodiments are used for supplement. Specific embodiments:

[0102] In this embodiment, the raw materials used in the smoldering reaction mixture prepared in process (1) include gasification slag with a water content of 36% and quartz sand with a particle size of 1-2 mm, which are mixed in a mass ratio of 1:2. At the same time, the raw materials used in the pyrolysis reaction mixture include carbon-rich organic solid waste with a water content of 20% and quartz sand with a particle size of 1-2 mm, which are mixed in a mass ratio of 1:1, and finally two kinds of mixture materials with porous properties are obtained.

[0103] Before feeding the two kinds of mixture materials into the two reaction furnaces, a certain thickness of large-particle quartz sand with a particle size of 5-8 mm is first filled into the bottom of each reaction furnace, and the quartz sand is just enough to cover the heating rods at the bottom of the reaction furnace.

[0104] Further, the two kinds of mixed mixture materials are filled into the two reaction furnaces respectively, and the inner cavities of the two reaction furnaces are filled, and then the electric heating mechanism at the bottom of the two reaction furnaces is turned on for preheating.

[0105] Afterwards, when the bottom thermocouple temperature of the material reaches 400 DEG C, the heating mechanism is closed, the first gas supply mechanism is opened for gas supply and ignition; in this embodiment, the component composition of the control gas is 21% O2, 79% N2, the Darcy flow rate of the gas is 5 cm / s, and the reaction is started.

[0106] As the smoldering reaction propagates upward, the temperature monitored by each thermocouple in the material along the height direction increases, the gas flow rate of the first gas supply mechanism is gradually changed so that the Darcy flow rate is controlled at about 3.5 cm / s, and the highest reaction temperature in the first reaction furnace is maintained at about 1000 DEG C, the oxygen concentration in the flue gas at the first smoke outlet is below 0.5%, and the CO concentration is about 25%.

[0107] At the same time, the temperature distribution in the second reaction furnace is monitored, and the highest temperature in the second reaction furnace is maintained at 400-600 DEG C by adjusting the flow rate of the flow distribution valve; as the reaction proceeds, the flow rate of the flow distribution valve is adjusted to 50% / 50%, at this time, the CO concentration in the flue gas discharged from the second smoke outlet is about 50%, and the oxygen concentration is 0%.

[0108] Correspondingly, by detecting the composition of the flue gas discharged from the gas purification / mixing device, it is found that the main components of the dried tail flue gas are: 0.1% O2, 32.7% N2, 7.1% CO2, 60% CO, 80 ppm NO x .

[0109] At the same time of the above smoldering reaction and pyrolysis reaction, the two feeding mechanisms are opened to synchronize feeding, ensuring that the two reaction furnaces are always filled. At the same time, the intermittent opening of the slag discharge mechanism at the bottom of the two reaction furnaces ensures the relative stability of the corresponding reaction front position in the two reaction furnaces. In addition, by screening the waste slag discharged from the two slag discharge mechanisms, recyclable quartz sand and recyclable (mixed into building materials for use) gasification slag ash, and high-calorific-value (calorific value above 4500 large calories) pyrolysis semi-coke are obtained.

[0110] The solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis in the application has the advantages of simple system composition, convenient control, high-value recycling of gasification slag and carbon-rich organic solid waste without using a large amount of external auxiliary energy, rapid preparation of low-oxygen CO-rich gas and pyrolysis semi-coke, improved recycling rate of internal available energy of gasification slag and carbon-rich organic solid waste, reduced treatment cost of gasification slag and carbon-rich organic solid waste, and good economic value and practical value.

[0111] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis, characterized by, The application comprises: a first reaction furnace, which is a smoldering furnace, the top of which is provided with a first flue gas outlet for discharging first flue gas generated by smoldering of the residue and a first feeding mechanism for feeding smoldering reaction mixture, and the bottom of which is provided with a first gas supply mechanism for supplying gas required for smoldering reaction and a first heating mechanism for heating the material at the bottom of the furnace; a second reaction furnace, which is embedded in the first reaction furnace and extends from the bottom to the top of the first reaction furnace; the top of the second reaction furnace is provided with a second flue gas outlet and a second feeding mechanism for discharging second flue gas generated by pyrolysis reaction and feeding pyrolysis reaction mixture, respectively; and the bottom of the second reaction furnace is provided with a second gas supply mechanism and a second heating mechanism; and the wall of the second reaction furnace is made of a material with good heat conduction performance, so that the heat generated by the smoldering reaction in the first reaction furnace can be transferred to the second reaction furnace; a condensing mechanism, which is in communication with the first flue gas outlet and the second flue gas outlet through pipelines, respectively, for condensing the first flue gas and the second flue gas; and a flow distribution valve is arranged corresponding to the condensed first flue gas, the inlet of which is in communication with the condensing mechanism, for outputting the condensed first flue gas in proportion, so that part of the first flue gas is sent into the second reaction furnace through the second gas supply mechanism, and the remaining first flue gas is transported to a gas purification / mixing device through a pipeline; a gas purification / mixing device, which is in communication with the condensing mechanism for condensing the second flue gas and the flow distribution valve through pipelines, respectively, for purifying and mixing the two condensed flue gases to obtain rich-burning fuel gas.

2. The solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis according to claim 1, characterized in that, A plurality of thermocouples are arranged along the axis in the first reaction furnace and the second reaction furnace, respectively, for real-time monitoring of the reaction temperature at different positions of the reaction furnace.

3. The solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis according to claim 1, characterized in that, The bottoms of the two reaction furnaces are respectively provided with residue discharge ports, and a residue discharging mechanism is arranged corresponding to the two residue discharge ports.

4. The solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis according to any one of claims 1-3, characterized in that, The second flue gas outlet is an annular gas outlet arranged between the first feeding mechanism and the second feeding mechanism. And / or At least one feeding mechanism is a screw feeding mechanism.

5. A solid waste treatment method based on gasification slag smoldering and organic solid waste pyrolysis, which is implemented using the solid waste treatment system based on gasification slag smoldering and organic solid waste pyrolysis according to any one of claims 1 to 4, characterized by, The application comprises the following processes: (1) preparing smoldering reaction mixture and pyrolysis reaction mixture; Mixing the residue with inert medium to prepare the smoldering reaction mixture, the mass ratio of the two being in the range of 1:1-1:6, and the water content of the residue being controlled in the range of 10%-80%; mixing the carbon-rich organic solid waste with inert medium to prepare the pyrolysis reaction mixture, the mass ratio of the two being in the range of 1:0.5-1:8; (2) filling the two kinds of mixture into the corresponding reaction furnace until the corresponding reaction furnace is filled; (3) starting the heating mechanism at the bottom of the first reaction furnace, preheating the mixture at the bottom of the first reaction furnace to the ignition temperature, and then stopping heating; (4) passing the reaction gas into the bottom of the first reaction furnace through the first gas supply mechanism and igniting, starting the smoldering reaction of the mixed material in the first reaction furnace, and sequentially forming a high-temperature high-oxygen oxidation zone, a high-temperature low-oxygen gasification zone, a medium-temperature low-oxygen pyrolysis zone and a low-temperature low-oxygen drying zone from bottom to top in the first reaction, respectively completing the high-temperature oxidation process, the high-temperature gasification process, the pyrolysis process and the drying process of the smoldering reaction mixed material, and obtaining the first flue gas and discharging it from the first flue gas outlet; The gas velocity of the reaction gas is controlled at 1cm / s~15cm / s, the oxygen concentration therein is 10%~30%, and the core reaction temperature in the high-temperature high-oxygen oxidation zone is not less than 900℃, and the oxygen concentration at the end of the high-temperature high-oxygen oxidation zone is controlled at 2%~6%; the gasification reaction temperature in the high-temperature low-oxygen gasification zone is controlled at above 800℃, and the oxygen concentration at the end of the high-temperature low-oxygen gasification zone is controlled at below 1%; (5) passing the condensed at least part of the first flue gas into the bottom of the second reaction furnace through the second gas supply mechanism, and controlling the flow distribution valve to adjust the flow of the condensed first flue gas passed into the second reaction furnace by the second gas supply mechanism, adjusting the temperature of the pyrolysis reaction in the second reaction furnace by controlling the flow, forming a low-oxygen / anaerobic pyrolysis zone with a temperature range of 400~600℃, continuously completing the pyrolysis reaction of the carbon-rich organic solid waste, and discharging the second flue gas obtained from the second flue gas outlet; (6) passing the condensed second flue gas and the condensed first flue gas not passed into the second reaction furnace into the gas purification / mixing device, and finally obtaining the rich-burning fuel gas and outputting.

6. The solid waste treatment method based on gasification slag smoldering and organic solid waste pyrolysis according to claim 5, characterized in that, In process (1), the gasification slag is a gasification coarse slag with a water content of less than 30%, and the mass ratio of the gasification coarse slag mixed with the inert medium is in the range of 1:1~1:3; Or The gasification slag is a gasification fine slag with a water content of more than 30%, and the mass ratio of the gasification fine slag mixed with the inert medium is in the range of 1:2~1:

5.

7. The solid waste treatment method based on gasification slag smoldering and organic solid waste pyrolysis according to claim 5, characterized by, In process (2), before the feeding and filling of the two mixed materials, a certain thickness of preheated filler is filled into the bottom of the two reaction furnaces, so that the preheated filler covers the heating mechanism at the bottom of the two reaction furnaces.

8. The solid waste treatment method based on gasification slag smoldering and organic solid waste pyrolysis according to any one of claims 5-7, characterized in that, In process (3), the preheating temperature of the mixed material is 250℃~400℃.

9. The solid waste treatment method based on gasification slag smoldering and organic solid waste pyrolysis according to any one of claims 5-7, characterized in that, In process (4), CO2 with a concentration range of 0~85% is mixed in the reaction gas sent into the first reaction furnace.

10. The solid waste treatment method based on gasification slag smoldering and organic solid waste pyrolysis according to any one of claims 5 to 7, characterized in that, In process (6), the waste slag discharged from the bottom of the second reaction furnace is screened to obtain high-calorific-value pyrolysis semi-coke.

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