Internal circulation system for drying, gasifying and melting sludge

Abstract

The utility model discloses an internal circulation system for sludge drying, gasifying and melting, which relates to the technical field of solid waste treatment and comprises gasifying and melting equipment, sludge drying equipment and a circulation device, the gasifying and melting equipment comprises a gasifying device and a melting device; the sludge drying equipment comprises a sludge feeding device and a sludge heat drying device; the circulating device comprises a first water removal device, a fan and a mixing and conveying device; the gas inlet end of the first dewatering device is connected with the gas outlet end of the melting device, and the first dewatering device is used for dewatering gas output by the melting device; the air outlet end of the first water removal device is connected with the air inlet end of the sludge heat drying device through the fan; the gas outlet end of the sludge heat drying device is connected to the gasification device through the mixing and conveying device. According to the gasification and melting internal circulation system for sludge drying, the resource utilization rate is increased, and the sludge drying cost is effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of solid waste treatment, and in particular to an internal circulation system for sludge drying, gasification and melting. Background Art

[0002] The sludge produced by sewage treatment plants is one of the solid wastes with a high water content. It is usually transported out after mechanical squeezing and dehydration in the sewage treatment plant. At this time, the water content is usually about 80%. However, for the subsequent disposal methods of sludge (landfill, incineration, fermentation, etc.), the water content of 80% is still too high, so further dehydration is required, which is generally called sludge drying. One of the main sludge drying methods is thermal drying, which provides heat to the sludge to evaporate water and achieve drying. In recent years, among the many sludge disposal methods, the sludge thermal drying process has been widely used in various countries because it can easily reduce, stabilize, harmless and resource the sludge in the production process of urban sewage treatment plants.

[0003] Most of the existing sludge thermal drying devices are independently set up, which require a large amount of heat energy (usually high-temperature air, which is mixed with sludge to dry the sludge). At the same time, the high-temperature air generated after sludge drying also carries a large amount of harmful substances, which also need to be further processed before discharge. This leads to a high cost of existing sludge thermal drying. Utility Model Content

[0004] In view of this, the purpose of the present application is to provide an internal circulation system for sludge drying, gasification and melting, so as to solve the technical problem of high cost of existing sludge thermal drying.

[0005] In order to achieve the above technical purpose, the present application provides an internal circulation system for sludge drying, gasification and melting, including a gasification and melting device, a sludge drying device and a circulation device;

[0006] The gasification and melting equipment comprises a gasification device and a melting device;

[0007] The gas outlet end of the gasification device is connected to the gas inlet end of the melting device;

[0008] The sludge drying equipment includes a sludge feeding device and a sludge thermal drying device;

[0009] The discharge end of the sludge feeding device is connected to the feed end of the sludge thermal drying device;

[0010] The circulation device includes a first water removal device, a fan and a mixing and conveying device;

[0011] The gas inlet end of the first dehydration device is connected to the gas outlet end of the melting device, and is used to dehydrate the gas output by the melting device;

[0012] The air outlet of the first water removal device is connected to the air inlet of the sludge thermal drying device through the fan;

[0013] The fan is used to transport the dehydrated gas to the sludge thermal drying device;

[0014] The gas outlet end of the sludge thermal drying device is connected to the gasification device through the mixing and conveying device;

[0015] The mixing and conveying device is used to mix water vapor, solid waste powder and gas conveyed from the gas outlet end of the sludge thermal drying device, and then convey them to the gasification device.

[0016] Further, it also includes a post-processing device;

[0017] The input end of the post-processing device is connected to the gas outlet end of the sludge thermal drying device through a conveying pipe;

[0018] A control valve is installed on the delivery pipe;

[0019] The control valve is configured to be turned on when the pressure in the delivery pipe reaches a preset pressure value;

[0020] The input end of the mixing and conveying device is connected to the pipe section of the conveying pipe between the sludge thermal drying device and the control valve.

[0021] Furthermore, the control valve is a regulating air valve.

[0022] Furthermore, the post-processing device includes a dust removal and material collection device, a second water removal device and a denitrification device;

[0023] The air inlet end of the dust removal and material collection device is connected to the air outlet end of the sludge thermal drying device through the conveying pipe;

[0024] The air outlet end of the dust removal and material collection device is connected to the air inlet end of the second water removal device;

[0025] The gas outlet end of the second water removal device is connected to the gas inlet end of the denitration device.

[0026] Furthermore, the gas outlet end of the denitration device is connected to a high-altitude emission chimney.

[0027] Furthermore, the discharge end of the dust removal and material collection device is connected to the gasification device through a circulation pipe.

[0028] Furthermore, the second water removal device is a condensation tower.

[0029] Furthermore, the first water removal device is a heat pump.

[0030] Furthermore, the gasification and melting equipment also includes a waste heat recovery device;

[0031] The waste heat recovery device is connected between the gas outlet end of the melting device and the gas inlet end of the first water removal device.

[0032] Furthermore, the waste heat recovery device is a waste heat boiler.

[0033] It can be seen from the above technical solutions that the internal circulation system for sludge drying, gasification and melting designed in this application combines the gasification and melting equipment with the sludge drying equipment through the circulation device, which has the following beneficial effects:

[0034] 1. The high-temperature air required by the sludge thermal drying device is provided by the hot gas discharged from the melting device, which reduces the amount of natural gas required to be burned by the sludge thermal drying device itself, thereby reducing the sludge drying cost.

[0035] 2. The gas containing harmful substances discharged from the sludge thermal drying device is mixed with water vapor and solid waste powder through a mixing and conveying device, and then transported to the gasification device. It is used as fuel for the gasification device and is used for combustion inside the gasification device to achieve harmless treatment. Therefore, there is no need to add processing equipment at the tail end, which reduces investment costs and reduces sludge drying costs.

[0036] 3. The gas with a certain temperature generated by the gasification and melting equipment is utilized, which improves the resource utilization rate, reduces the treatment cost of the gas discharged by the gasification and melting equipment, avoids the full load operation of the tail gas treatment device of the gasification and melting equipment, and increases the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0038] Figure 1 This is a schematic diagram of the structure of an internal circulation system for sludge drying, gasification and melting provided in this application;

[0039] In the figure: 1. Gasification raw material feeding mechanism; 2. Gasification furnace; 3. Melting furnace; 4. Waste heat recovery device; 5. First water removal device; 6. Fan; 7. Sludge feeding device; 8. Sludge thermal drying device; 9. Control valve; 10. Dust removal and collecting device; 11. Second water removal device; 12. High-altitude emission chimney; 13. Denitrification device; 14. Mixing and conveying device; 15. Oxygen enrichment generator. DETAILED DESCRIPTION

[0040] The technical solutions of the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, not all of them. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments in the embodiments of the present application are within the scope of protection of the embodiments of the present application.

[0041] In the description of the embodiments of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0042] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a replaceable connection, or an integral connection, it can be a mechanical connection, it can be an electrical connection, it can be a direct connection, it can be indirectly connected through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0043] The embodiment of the present application discloses an internal circulation system for sludge drying, gasification and melting.

[0044] See also Figure 1 An embodiment of an internal circulation system for sludge drying, gasification and melting provided in the present application includes:

[0045] Gasification and melting equipment, sludge drying equipment and circulation devices.

[0046] Gasification melting technology is an important development direction for the efficient and clean incineration of the new generation of solid waste. This technology combines the advantages of garbage gasification and ash melting technology. Its working principle is that solid waste enters the gasifier 2 after pretreatment, and undergoes thermal cracking and gasification in an oxygen-deficient reducing atmosphere. Then the gasified solid waste enters the melting furnace 3 for high-temperature combustion to generate glassy slag. This technology achieves complete harmlessness, significant volume reduction, wide material adaptability and efficient energy and material recovery, and is called a new generation of waste treatment technology.

[0047] The gasification and melting equipment includes a gasification device and a melting device.

[0048] The gas outlet end of the gasification device is connected to the gas inlet end of the melting device.

[0049] The gasification device specifically includes a gasifier 2, a gasification raw material feeding mechanism 1, an oxygen-enriched generator 15, and a gasification igniter, etc. The gasification raw material feeding mechanism 1 is connected to the gasifier 2 for providing the gasification raw material to the gasifier 2, and the oxygen-enriched generator 15 is connected to the gasifier 2 for providing oxygen to the gasifier 2. The gasification igniter is installed in the gasifier 2 for igniting the gasification raw material.

[0050] The melting device includes a melting furnace 3, a molten raw material feeding mechanism and a melting igniter; the air inlet end of the melting furnace 3 is connected to the air outlet end of the gasification furnace 2; the molten raw material feeding mechanism is connected to the melting furnace 3 to provide molten raw materials; the melting igniter is installed on the melting furnace 3 to ignite the molten raw materials and the transported flue gas and the molten raw materials.

[0051] The gasification and melting equipment of the present application is a gasification and melting equipment currently available and used in the market, and specifically refers to a fluidized bed gasification equipment.

[0052] The sludge drying equipment includes a sludge feeding device 7 and a sludge thermal drying device 8 .

[0053] The discharge end of the sludge feeding device 7 is connected to the feed end of the sludge thermal drying device 8, and is used to convey sludge raw materials to the sludge thermal drying device 8. The sludge thermal drying device 8 in the present application is an existing low-temperature positive pressure drying device for sludge drying, that is, a low-temperature dryer, which is composed of a fluidized drying cylinder and a gas-solid separation cylinder, wherein a sludge crushing knife is installed inside the fluidized drying cylinder.

[0054] The sludge drying in this application refers to the sludge drying equipment that is currently available and used in the equipment market, such as fluidized bed drying equipment, belt drying equipment, paddle drying equipment, horizontal turntable drying equipment, vertical turntable drying equipment, etc., specifically referring to fluidized bed drying equipment.

[0055] The circulation device includes a first water removal device 5 , a positive pressure fan 6 and a mixing and conveying device 14 .

[0056] The air inlet end of the first water removal device 5 is connected to the air outlet end of the melting device, and is used to dehydrate the gas output by the melting device; the air outlet end of the first water removal device 5 is connected to the air inlet end of the sludge thermal drying device 8 through the fan 6; the fan 6 is used to transport the dehydrated gas to the sludge thermal drying device 8.

[0057] The gas outlet of the sludge thermal drying device 8 is connected to the gasification device through a mixing and conveying device 14; the mixing and conveying device 14 is used to mix water vapor, solid waste powder and gas transported from the gas outlet of the sludge thermal drying device 8, and then transport them to the gasification device. The mixing and conveying device 14 is a steam solid waste powder mixing device. The solid waste powder refers to solid waste powder with a relatively high carbon content, such as biomass and impure crushed coal.

[0058] The internal circulation system for sludge drying, gasification and melting designed in this application has the following working principle:

[0059] 1. First, the sludge feeding device 7 is started to convey the sludge squeezed by the filter press into the sludge thermal drying device 8. After the sludge conveyed by the sludge feeding device 7 enters the fluidized drying cylinder, it is crushed by the rotating sludge crushing knife. At the same time, the external heat source gas conveyed by the fan 6 enters the bottom of the fluidized drying cylinder through the pipeline, and the crushed sludge is lifted and dried. After the sludge is dried, it forms fine particles, which are carried by the airflow to the gas-solid separation cylinder, and the gas-solid separation cylinder separates the solids with larger specific gravity.

[0060] 2. The gas separated from the gas-solid separation cylinder is mixed with water vapor and solid waste powder in a certain proportion through a pipeline conveying device 14 and then sent to the gasifier 2. After high-temperature catalysis, this mixture can produce a large amount of CO and hydrogen. The large amount of combustible gas produced can replace natural gas, thereby eliminating the hot air furnace device connected to the bottom of the original gasifier 2.

[0061] 3. The gas mixed with solid waste powder and water vapor enters the bottom of the gasifier 2, and the oxygen-enriched generator 15 provides oxygen to enter the bottom of the gasifier 2. The gasification igniter at the bottom of the gasifier 2 is started to ignite the mixed gas. The mixed gas burns and emits a large amount of heat, raising the temperature inside the gasifier 2. The sludge carried by the mixed gas is in a high temperature state, and the organic part of the sludge is gasified to form flue gas, and the inorganic part forms ash and fly ash; the ash gathers at the bottom of the gasifier 2 and is collected by the collecting device; the fly ash and flue gas leave the gasifier 2 and enter the melting furnace 3.

[0062] 4. Further air is added to the melting furnace 3 to make the flue gas reach a complete state. The melting igniter is started to ignite the flue gas and make it burn completely. The fly ash will be molten under high temperature conditions, gathered together through the furnace wall, and finally fall into the internal water tank of the quenching conveyor under the melting furnace 3 to form a glassy slag.

[0063] 5. The high-temperature air generated after combustion leaves the melting furnace 3, passes through the first water removal device 5 and the fan 6 and reaches the sludge thermal drying device 8, thus completing a process cycle.

[0064] The sludge drying, gasification and melting internal circulation system designed in this application combines the gasification and melting equipment with the sludge drying equipment through the circulation device, which has the following beneficial effects:

[0065] 1. The high-temperature air required by the sludge thermal drying device 8 is provided by the hot gas discharged from the melting device, which reduces the amount of natural gas required to be burned by the sludge thermal drying device 8 itself, thereby reducing the sludge drying cost.

[0066] 2. The gas containing harmful substances discharged from the sludge thermal drying device 8 passes through the mixing and conveying device 14, is mixed with water vapor and solid waste powder, and then conveyed to the gasification device, and is used as fuel for the gasification device. It is used for combustion inside the gasification device to achieve harmless treatment, so that there is no need to add processing equipment at the tail end, reducing investment costs and lowering sludge drying costs.

[0067] 3. The gas with a certain temperature generated by the gasification and melting equipment is utilized, which improves the resource utilization rate, reduces the treatment cost of the gas discharged by the gasification and melting equipment, avoids the full load operation of the tail gas treatment device of the gasification and melting equipment, and increases the service life.

[0068] The above is an embodiment of the present application provided in the embodiment of a sludge drying, gasification and melting internal circulation system. The following is an embodiment of the present application provided in the embodiment of a sludge drying, gasification and melting internal circulation system. For details, please refer to Figure 1 .

[0069] Based on the solution of the above embodiment 1:

[0070] Furthermore, a post-processing device is also included.

[0071] The input end of the post-treatment device is connected to the outlet end of the sludge thermal drying device 8 through a conveying pipe; a control valve 9 is installed on the conveying pipe; the control valve 9 is configured to be turned on when the pressure in the conveying pipe reaches a preset pressure value; the input end of the mixing conveying device 14 is connected to the section of the conveying pipe between the sludge thermal drying device 8 and the control valve 9.

[0072] It should be noted that since oxygen will be continuously added during the airflow circulation process, the pipeline pressure in the airflow circulation will continue to increase. In order to solve this problem, this application adds a post-processing device to form a branch process, and connects it to the melting device through a delivery pipe, and installs a pressure transmitter on the delivery pipe for pressure detection. At the same time, a control valve 9 is configured to control the delivery pipe to open and close. When the control valve 9 detects that the delivery pipe pressure exceeds the set value through the pressure transmitter, it puts itself in a conducting state, thereby guiding part of the gas to the post-processing device to avoid excessive pipeline pressure and cause operational failures.

[0073] Furthermore, the control valve 9 is a regulating air valve.

[0074] Furthermore, with regard to the design of the post-processing device, it may include a dust removal and material collection device 10 , a second water removal device 11 and a denitrification device 13 .

[0075] The air inlet end of the dust removal and collecting device 10 is connected to the air outlet end of the sludge thermal drying device 8 through a conveying pipe. The dust removal and collecting device 10 can be a combination of an existing cyclone collector and a nano dust collector, or one of them, or a bag dust collector, without specific limitation.

[0076] The air outlet end of the dust removal and material collection device 10 is connected to the air inlet end of the second water removal device 11 , and the air outlet end of the second water removal device 11 is connected to the air inlet end of the denitration device 13 .

[0077] The gas separated by the dust removal and material collection device 10 is then dehydrated by the second dehydration device 11, and then denitrated at low temperature by the denitration device 13 to achieve tail gas purification.

[0078] Furthermore, the gas outlet end of the denitration device 13 is connected to a high-altitude emission chimney 12 , and the tail gas after purification is then discharged into the atmosphere through the high-altitude emission chimney 12 .

[0079] Furthermore, the discharge end of the dust removal and collection device 10 is connected to the gasification device through a circulation pipe. The solid matter collected by the dust removal and collection device 10 is then transported to the gasification raw material feeding mechanism 1 of the gasification furnace 2 through a conveying system, and then a cycle is realized.

[0080] Furthermore, the second water removal device 11 may be a condensation tower.

[0081] Furthermore, the first water removal device 5 may be a heat pump.

[0082] Furthermore, in order to improve the heat recovery efficiency, the gasification and melting equipment also includes a waste heat recovery device 4 .

[0083] The waste heat recovery device 4 is connected between the gas outlet end of the melting device and the gas inlet end of the first water removal device 5 , and the waste heat recovery device 4 may be a waste heat boiler.

[0084] The gasifier 2 gasifies solid waste through high-temperature pyrolysis to produce high-temperature synthesis gas. The high-temperature synthesis gas reaches the melting furnace 3 through a pipeline and is mixed with oxygen for full combustion. The combustion temperature reaches above 1200°C. The high-temperature gas that is completely burned in the melting furnace 3 reaches the waste heat boiler through a pipeline, and transfers the heat it carries to the waste heat boiler. The waste heat boiler uses part of the heat of the high-temperature air to generate electricity. After the high-temperature air recovers part of the heat through the waste heat boiler, it is dehydrated through a heat pump, and the temperature can be reduced to about 350°C. After that, the 350°C high-temperature air reaches the sludge thermal drying device 8 through a pipeline. The sludge thermal drying mixes the sludge with the high-temperature air, dilutes the water in the sludge into the high-temperature air, and completes the drying.

[0085] The above is a detailed introduction to the sludge drying, gasification and melting internal circulation system provided in the present application. For general technicians in this field, according to the ideas of the embodiments of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. An internal circulation system for sludge drying, gasification and melting, characterized in that: Including gasification and melting equipment, sludge drying equipment and circulation device; The gasification and melting equipment comprises a gasification device and a melting device; The gas outlet end of the gasification device is connected to the gas inlet end of the melting device; The sludge drying equipment comprises a sludge feeding device (7) and a sludge thermal drying device (8); The discharge end of the sludge feeding device (7) is connected to the feed end of the sludge thermal drying device (8); The circulation device comprises a first water removal device (5), a fan (6) and a mixing and conveying device (14); The gas inlet end of the first dehydration device (5) is connected to the gas outlet end of the melting device, and is used to dehydrate the gas output by the melting device; The air outlet of the first water removal device (5) is connected to the air inlet of the sludge thermal drying device (8) via the fan (6); The fan (6) is used to transport the gas after dehydration to the sludge thermal drying device (8); The gas outlet end of the sludge thermal drying device (8) is connected to the gasification device via the mixing and conveying device (14); The mixing and conveying device (14) is used to mix water vapor, solid waste powder and gas conveyed from the gas outlet of the sludge thermal drying device (8), and then convey them to the gasification device.

2. The internal circulation system for sludge drying, gasification and melting according to claim 1 is characterized in that: Also included is a post-processing device; The input end of the post-treatment device is connected to the gas outlet end of the sludge thermal drying device (8) via a conveying pipe; A control valve (9) is installed on the delivery pipe; The control valve (9) is configured to be opened when the pressure in the delivery pipe reaches a preset pressure value; The input end of the mixing and conveying device (14) is connected to the pipe section of the conveying pipe between the sludge thermal drying device (8) and the control valve (9).

3. The internal circulation system for sludge drying, gasification and melting according to claim 2 is characterized in that: The control valve (9) is a regulating air valve.

4. The internal circulation system for sludge drying, gasification and melting according to claim 2 is characterized in that: The post-processing device comprises a dust removal and material collection device (10), a second water removal device (11) and a denitrification device (13); The air inlet end of the dust removal and material collection device (10) is connected to the air outlet end of the sludge thermal drying device (8) through the conveying pipe; The air outlet end of the dust removal and material collection device (10) is connected to the air inlet end of the second water removal device (11); The gas outlet end of the second water removal device (11) is connected to the gas inlet end of the denitration device (13).

5. The internal circulation system for sludge drying, gasification and melting according to claim 4 is characterized in that: The gas outlet end of the denitration device (13) is connected to a high-altitude emission chimney (12).

6. The internal circulation system for sludge drying, gasification and melting according to claim 4 is characterized in that: The discharge end of the dust removal and material collection device (10) is connected to the gasification device via a circulation pipe.

7. The internal circulation system for sludge drying, gasification and melting according to claim 4 is characterized in that: The second water removal device (11) is a condensation tower.

8. The internal circulation system for sludge drying, gasification and melting according to claim 1 is characterized in that: The first water removal device (5) is a heat pump.

9. The internal circulation system for sludge drying, gasification and melting according to claim 1, characterized in that: The gasification and melting equipment further comprises a waste heat recovery device (4); The waste heat recovery device (4) is connected between the gas outlet end of the melting device and the gas inlet end of the first water removal device (5).

10. The internal circulation system for sludge drying, gasification and melting according to claim 9, characterized in that: The waste heat recovery device (4) is a waste heat boiler.

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