An integrated process and equipment for drying, crushing and conveying sludge or peat materials

Abstract

The present invention discloses an integrated process and equipment for conveying sludge or peat drying and crushing materials, which relates to the technical field of material supply, including: feeding a set mass of pre-fluidized powder into a circulating fluidized bed, using the boiler secondary air as the supply source of fluidizing air, adjusting the circulating fluidized bed to enter a pre-fluidized operation state, and forming a high-speed particle source; the coal sludge or sludge source particles processed by the extruder equipment are input into the pre-fluidized circulating fluidized bed, and the fine powder flow reaching the cutting particle size is incorporated into the secondary air duct and sent to the boiler; the particles whose particle size meets the set requirements enter the supersonic mill, and after the screen is rectified, they enter the crushing chamber through the drop port, and the crushed fluidized material is directly incorporated into the secondary air duct and sent to the boiler, or after being filtered by a bag filter, the dried material enters the powder bin for periodic storage. The drying process of the present invention is fast, safe and reliable; it occupies a small area and has a compact process layout; the tail gas is clean and has a small flow rate, and the drying cost is low, achieving the dual effects of energy saving and environmental protection.

Description

Technical Field

[0001] The invention relates to the technical field of material supply, and in particular to an integrated process and equipment for conveying sludge or peat drying and crushing materials. Background Art

[0002] Coal slime or sewage sludge can be used for boiler combustion, especially when mixed with low calorific value coal such as coal gangue, which can reduce the amount of clean coal used. However, the key obstacle to its resource utilization is its high moisture content. Various drying technologies can effectively reduce the moisture content in coal slime or sewage sludge and increase its calorific value. The current main drying methods are mechanical dehydration, evaporative dehydration and non-evaporative dehydration. Among them, evaporative dehydration is the mainstream disposal process, which mainly includes high-temperature drying and low-temperature drying.

[0003] High temperature drying generally refers to drying in a 600℃ high temperature flue gas environment, which has the advantages of high drying intensity, large processing capacity, stable operation, and low maintenance cost, but it also has the disadvantages of high drying temperature, explosion hazard, large drying tail gas volume, and high dust content; low temperature drying process mainly includes drum drying, steam tube, mesh belt continuous low temperature dehumidification and drying, etc., especially drum drying method has the advantages of reliable equipment operation, strong overload resistance, simple operation, and high thermal efficiency. For those adjacent to thermal power plants, the heat medium is mostly changed to the four-stage steam extraction heat source of the power plant steam turbine. However, due to the use of downstream mode, the gas-solid two-phase downstream contact heat exchange has a small contact area and needs to stay in the dryer for a long time (8 to 12 minutes). Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an integrated process and equipment for drying, crushing and conveying sludge or peat materials, which is based on a primary circulating fluidized bed collision crushing + low-temperature drying, superimposed with a secondary air flow mill pulverization + low-temperature drying, gas-solid countercurrent contact, and greatly enhanced mechanical collision cutting effect, and rapid pulverization and drying of particles, which effectively avoids the shortcomings of scaling, agglomeration and long drying time of coal slime or sludge in conventional low-temperature drying equipment, and the drying process is faster, safer and more reliable; at the same time, the fluidized bed and air flow mill have fewer additional supporting equipment, a small footprint, and a compact process layout; the tail gas is clean and has a small flow rate, and the drying cost is low, achieving the dual effects of energy saving and environmental protection.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides an integrated process for drying, crushing and conveying sludge or peat, based on a primary circulating fluidized bed collision crushing combined with low temperature drying, and superimposed with a secondary air flow grinding combined with low temperature drying; comprising:

[0007] Feed a set mass of pre-fluidized powder into the circulating fluidized bed, use the boiler secondary air as the fluidizing air supply source, adjust the circulating fluidized bed to enter the pre-fluidized operation state, and form a high-speed particle source;

[0008] The coal sludge or sewage sludge source particles processed by the extruder equipment are input into the pre-fluidized circulating fluidized bed, and the fine powder flow reaching the cut particle size is merged into the secondary air duct and sent to the boiler;

[0009] Particles with a size that meets the set requirements enter the supersonic mill, and after being rectified by the screen, they enter the crushing chamber through the drop port. The crushed fluidized material is directly incorporated into the secondary air duct and sent to the boiler, or after being filtered by the bag dust collector, the dry material enters the powder bin for periodic storage.

[0010] As a further implementation method, first open the boiler secondary air inlet at the throat of the circulating fluidized bed, send in the designed air volume of secondary air, and then send the pre-fluidized powder that meets the particle size requirements to the circulating fluidized bed inlet.

[0011] As a further implementation, the particle size of the pre-fluidized powder is 500-800 microns, and the temperature of the boiler secondary air is 300-350°C.

[0012] As a further implementation method, the coal slime or sewage sludge is transported to the extruder equipment via a bucket elevator, and processed into source particles meeting the particle size and mass flow rate requirements by the extruder equipment; the source particles enter the circulating fluidized bed through a closed conveying pipeline.

[0013] As a further implementation method, the source particles undergo heat and mass transfer exchange with the boiler secondary air under the combined action of collision and cutting of high-speed particles in the circulating fluidized bed. The particles rapidly expand, rupture, and are cyclically impacted and cut. The particles are refined to a set particle size, carried by the airflow to the cyclone dust collector, merged into the secondary air duct, and then sent to the boiler.

[0014] As a further implementation method, particles that do not meet the particle size requirements are automatically returned to the circulating fluidized bed through the automatic return pipe of the cyclone dust collector under the action of gravity, and continue to participate in the collision and cutting action of high-speed particles.

[0015] As a further implementation method, the steam extraction or compressed nitrogen from the turbine passes through the steam extraction or compressed nitrogen inlet of the supersonic mill and is ejected from the nozzle, and the intersection of the airflow is designed to be coaxial with the falling path of the coal slime or sludge particles. Under the high-speed impact, collision and friction of the supersonic airflow, the coal slime or sludge particles are further crushed.

[0016] In the second aspect, an embodiment of the present invention further provides an integrated equipment for conveying sludge or peat drying and crushing materials, including a circulating fluidized bed with a cyclone dust collector connected in parallel on one side; the circulating fluidized bed is provided with a pre-fluidized powder inlet, the top of the circulating fluidized bed is connected to an extruder device through a closed conveying pipe, and the bottom is connected to a supersonic mill, and a boiler secondary air inlet is provided at the connection between the supersonic mill and the circulating fluidized bed; the input end of the extruder device is connected to a bucket elevator, and one side of the supersonic mill is connected to a bag dust collector.

[0017] As a further implementation, an electric ash discharge valve is installed at the connection between the supersonic mill and the circulating fluidized bed;

[0018] A conical blocking sieve plate is arranged inside the supersonic mill, and a steam turbine extraction steam or compressed nitrogen inlet is arranged at the lower side of the conical blocking sieve plate.

[0019] As a further implementation method, the bottom of the supersonic mill is connected to a slag bin, and an electric slag discharge valve is installed at the outlet of the slag bin.

[0020] The beneficial effects of the present invention are as follows:

[0021] (1) The present invention is based on a primary circulating fluidized bed collision crushing + low-temperature drying, superimposed with a secondary air flow grinding + low-temperature drying. With the help of the circulating fluidized crushing process, the violent transfer, collision and cutting composite effect of high-speed particles on coal slime and sludge particles is enhanced; the contact area between the particles refined by the primary fluidized bed and the low-temperature heat source is greatly increased, and the heat and mass transfer effects with the low-temperature heat source and high-speed particles are simultaneously promoted; the two complement each other, significantly improving the shortcomings of conventional low-temperature drying methods such as moisture absorption and scaling, agglomeration, and long drying time, and the drying process is faster, safer, and more reliable.

[0022] (2) The equipment of the present invention uses a secondary supersonic grinding process to greatly increase the contact area between the powder particles and the low-temperature heat source, and the particles are thoroughly dried and the calorific value is significantly improved. The particles can be directly stored in the warehouse as a spare fuel, or sprayed into the furnace as fuel powder, which promotes the complete combustion of the particles, and the harmful elements are completely converted into mineral slag for complete treatment, thereby reducing the generation of secondary pollutants such as dioxins due to low-temperature incineration, and significantly improving the environmental protection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 It is a schematic diagram of the equipment structure according to one or more embodiments of the present invention.

[0025] Among them, 1. bucket elevator, 2. extruder equipment, 3. cutter, 4. extrusion particle mold, 5. closed conveying pipeline, 6. circulating fluidized bed feed port, 7. pre-fluidized powder inlet, 8. circulating fluidized bed, 9. boiler secondary air inlet, 10. electric ash discharge valve, 11. supersonic mill, 12. outlet, 13. cyclone dust collector, 14. automatic return pipe, 15. electric slag discharge valve, 16. conical blocking screen plate, 17. turbine extraction steam or compressed nitrogen inlet, 18. exhaust pipe, 19. bag dust collector, 20. electric slag discharge valve, 21. slag bin, 22. pneumatic ash conveying system, 23. electric slag discharge valve, 24. automatic control system. DETAILED DESCRIPTION

[0026] Embodiment 1:

[0027] This embodiment provides an integrated process for drying, crushing and conveying sludge or peat, which has two-step crushing and heat and mass transfer characteristics, based on a primary circulating fluidized bed collision crushing + low-temperature drying, superimposed secondary air flow grinding + low-temperature drying, gas-solid countercurrent contact, greatly enhanced mechanical collision cutting effect, rapid particle pulverization and drying, which can effectively avoid the scaling, agglomeration and long drying time of coal sludge or sludge in conventional low-temperature drying equipment, and the drying process is faster, safer and more reliable. Including:

[0028] A set mass of pre-fluidized powder is fed into the circulating fluidized bed 8, and the boiler secondary air is used as the fluidizing air supply source, and the circulating fluidized bed 8 is adjusted to enter the pre-fluidized operation state, and a high-speed particle source is formed;

[0029] The coal sludge or sewage sludge source particles processed by the extruder device 2 are input into the pre-fluidized circulating fluidized bed, and the fine powder flow reaching the cut particle size is merged into the secondary air duct and sent to the boiler;

[0030] The particles with the particle size meeting the set requirements enter the supersonic mill 11 (supersonic jet mill), and after being rectified by the screen, they enter the crushing chamber through the drop port. The crushed fluidized material is directly incorporated into the secondary air duct and sent to the boiler, or after being filtered by the bag dust collector 19, the dry material enters the powder bin for periodic storage.

[0031] The specific process is:

[0032] Open the boiler secondary air inlet 9 at the throat of the circulating fluidized bed 8, send in the secondary air of the designed air volume, and then send the coal powder and other particles that meet the particle size requirements, among which the particle size of the prefluidized powder is 500-800 microns, and the quality is similar; to the inlet of the circulating fluidized bed 8 through the prefluidized powder inlet 7, and establish a stable prefluidized state in the circulating fluidized bed 8.

[0033] The coal slime or sewage sludge is transported to the entrance of the extruder device 2 via the bucket elevator 1. An extrusion particle mold 4 and a cutter 3 are provided at the tail of the extruder device 2. After the sewage sludge or coal slime is processed by the extruder device 2 into source particles that meet the particle size and mass flow rate requirements (for example, processed into source particles of about 5 mm), it is discharged into the conveying closed pipe 5. The particles fall into the pre-fluidized circulating fluidized bed 8 through the conveying closed pipe 5.

[0034] Under the combined effects of collision and cutting of high-speed particles in the circulating fluidized bed 8, the source particles simultaneously exchange heat and mass with the boiler secondary air, and the particles rapidly expand, break, and are circularly impacted and cut. The particles are refined to a certain particle size and carried by the airflow to the cyclone dust collector 13. The gas powder that meets the cutting particle size requirements flows through the outlet 12 of the cyclone dust collector, merges into the secondary air duct, and is sent to the boiler. In this embodiment, the boiler secondary air at 300-350°C is used as the supply source of fluidizing air, and the circulating fluidized bed 8 is adjusted to enter the pre-fluidized operation state, and a high-speed particle source is formed.

[0035] The large-size particles are automatically returned to the circulating fluidized bed 8 under the action of gravity through the automatic return pipe 14 at the bottom of the cyclone dust collector 13, and continue to participate in the collision and cutting action of the high-speed particles; after the electric ash discharge valve 10 arranged at the bottom of the circulating fluidized bed 8 is started, the coal slime or sludge particles of the set particle size (for example, the particle size of 500-800 microns) fall into the supersonic mill 11, and after being rectified by the conical blocking screen plate 16, the turbine extraction steam or compressed nitrogen passes through the turbine extraction steam or compressed nitrogen inlet 17 at the bottom of the supersonic mill 11 and is sprayed out from the nozzle, and the intersection point of the airflow is designed to be coaxial with the falling path of the coal slime or sludge particles. Under the high-speed impact, collision, friction, etc. of the supersonic airflow, the coal slime or sludge particles are further crushed.

[0036] The crushed fluidized gas powder flow can be directly merged into the secondary air duct and sent to the boiler. At the same time, it can also be filtered by the bag filter 19, and the dry material can be stored in the subsequent powder bin through the pneumatic ash conveying system 22 of the bag filter 19. The slag-carrying air flow is filtered and purified, and then discharged cleanly through the exhaust duct 18 of the bag filter 13.

[0037] The bottom of the supersonic mill 11 is connected to the slag bin 21 via an electric slag discharge valve 20. An electric slag discharge valve 23 is provided at the bottom of the slag bin 21 to prepare for equipment maintenance or special requirements to empty the equipment. Among them, all digital signals of the system are sent to the automatic control system 24 to realize automatic control operation of the system.

[0038] This embodiment uses the circulating fluidized crushing process to strengthen the violent transfer, collision and cutting composite effect of high-speed particles on coal slime and sludge particles; the contact area between the particles after primary fluidized bed refinement and the low-temperature heat source is greatly improved, and the heat and mass transfer effects with the low-temperature heat source and high-speed particles are simultaneously promoted; the two complement each other and significantly improve the shortcomings of conventional low-temperature drying methods such as moisture absorption and scaling, agglomeration, and long drying time, making the drying process faster, safer, and more reliable.

[0039] With the help of the constructed secondary supersonic grinding process, this embodiment can greatly increase the contact area between the powder particles and the low-temperature heat source again, and the particles are thoroughly dried and the calorific value is significantly improved. They can be directly stored in the warehouse as spare fuel, or sprayed into the furnace as fuel powder, which promotes the complete combustion of the particles, and the harmful elements are completely converted into mineral slag for complete treatment, thereby reducing the generation of dioxins and other derivative secondary pollutants due to low-temperature incineration, and significantly improving the environmental protection effect.

[0040] Embodiment 2:

[0041] This embodiment provides an integrated equipment for conveying sludge or peat drying and crushing materials, such as Figure 1 As shown, it includes a bucket elevator 1, an extruder device 2, a circulating fluidized bed 8, a cyclone dust collector 13, a supersonic mill 11, a bag dust collector 19, a slag bin 21, etc. The bucket elevator 1 is connected to the input end of the extruder device 2 to deliver coal slime or sludge to the inlet of the extruder device 2; an extrusion particle mold 4 is arranged at the output end of the extruder device 2, and a cutter 3 is installed on the top of the extrusion particle mold 4 to obtain particles that meet the extrusion particle size requirements.

[0042] The particle extrusion die 4 and the cutter 3 are both based on the existing technology, which will not be described in detail here.

[0043] The top of the circulating fluidized bed 8 is connected to the output end of the extruder device 2 through a closed conveying pipe 5. Due to the height difference between the extruder device 2 and the circulating fluidized bed 8, the closed conveying pipe 5 is inclined. A pre-fluidized powder inlet 7 is set near the top of the circulating fluidized bed 8 for inputting pre-sulfurized materials.

[0044] The cyclone dust collector 13 is connected in parallel with the circulating fluidized bed 8, that is, the cyclone dust collector 13 near the top is connected with the circulating fluidized bed 8 near the top, and the cyclone dust collector 13 near the bottom is connected with the circulating fluidized bed 8 near the bottom through an automatic return pipe 14, and the automatic return pipe 14 is inclined toward the circulating fluidized bed 8. An outlet 12 is provided at the top of the cyclone dust collector 13 for discharging primary air; an electric slag discharge valve 15 is installed at the bottom outlet of the cyclone dust collector 13.

[0045] The bottom of the circulating fluidized bed 8 is connected to the top of the supersonic mill 11, and an electric ash discharge valve 10 is installed at the connection between the two, and the connection is connected to the boiler secondary air inlet 9; one side of the circulating fluidized bed 8 is connected to the bag dust collector 19 through a pipeline, and the bottom of the supersonic mill 11 is connected to the slag bin 21.

[0046] Furthermore, a conical blocking screen plate 16 is fixed in the middle of the supersonic mill 11, and the conical blocking screen plate 16 has a downwardly inclined surface. The conical blocking screen plate 16 of this embodiment is a conical screen plate with a diameter to height ratio of 10:1 to 5:1.

[0047] The supersonic mill 11 is connected to the steam turbine extraction or compressed nitrogen inlet 17, which is located below the conical blocking screen plate 16. An electric slag discharge valve 20 is installed at the connection between the slag bin 21 and the supersonic mill 11, and an electric slag discharge valve 23 is installed at the bottom outlet of the slag bin 21.

[0048] An exhaust duct 18 is arranged on the top of the bag filter 19, and a pneumatic dust conveying system 22 is arranged on the bottom. This embodiment also includes an automatic control system 24 for controlling all digital signals in the equipment.

[0049] Each electric slag discharge valve in this embodiment adopts a jaw type electric slag discharge valve.

[0050] The circulating fluidized bed 8 and the jet mill of this embodiment have less additional supporting equipment, small footprint, compact process layout, and saved civil engineering costs; the tail gas is clean and has a small flow rate, and the drying cost is low, achieving the dual effects of energy saving and environmental protection.

[0051] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A sludge or peat drying, crushing and material transportation integrated process, characterized in that: Based on a circulating fluidized bed collision crushing combined with low temperature drying, superimposed with a secondary air flow grinding combined with low temperature drying; including: Feed a set mass of pre-fluidized powder into the circulating fluidized bed, use the boiler secondary air as the fluidizing air supply source, adjust the circulating fluidized bed to enter the pre-fluidized operation state, and form a high-speed particle source; The particle size of the pre-fluidized powder is 500-800 microns, and the temperature of the boiler secondary air is 300-350°C; the coal sludge or sludge source particles processed by the extruder equipment are input into the pre-fluidized circulating fluidized bed, and the fine powder flow with the cut particle size is merged into the secondary air duct and sent to the boiler; Particles with a size that meets the set requirements enter the supersonic mill, and after being rectified by the screen, they enter the crushing chamber through the drop port. The crushed fluidized material is directly incorporated into the secondary air duct and sent to the boiler, or after being filtered by the bag dust collector, the dry material enters the powder bin for periodic storage.

2. The integrated process for drying, crushing and conveying sludge or peat materials according to claim 1, characterized in that: First, open the boiler secondary air inlet at the throat of the circulating fluidized bed, send in the designed secondary air volume, and then send the pre-fluidized powder that meets the particle size requirements to the circulating fluidized bed inlet.

3. The integrated process for drying, crushing and conveying sludge or peat materials according to claim 1, characterized in that: The coal slime or sewage sludge is transported to the extruder equipment through the bucket elevator and processed into source particles meeting the particle size and mass flow rate requirements by the extruder equipment; the source particles enter the circulating fluidized bed through a closed conveying pipeline.

4. The integrated process for drying, crushing and conveying sludge or peat materials according to claim 1 or 3, characterized in that: Under the combined action of collision and cutting of high-speed particles in the circulating fluidized bed, the source particles exchange heat and mass with the boiler secondary air. The particles quickly expand, rupture and are cyclically impacted and cut. The particles are refined to the set particle size and are carried by the airflow to the cyclone dust collector, merged into the secondary air duct, and then sent to the boiler.

5. The integrated process for drying, crushing and conveying sludge or peat materials according to claim 4, characterized in that: Particles that do not meet the particle size requirements are automatically returned to the circulating fluidized bed through the automatic return pipe of the cyclone dust collector under the action of gravity, and continue to participate in the collision and cutting action of high-speed particles.

6. The integrated process for drying, crushing and conveying sludge or peat materials according to claim 1, characterized in that: The steam extraction or compressed nitrogen from the turbine passes through the steam extraction or compressed nitrogen inlet of the supersonic mill and is ejected from the nozzle. The intersection of the airflow is designed to be coaxial with the falling path of the coal slime or sludge particles. Under the high-speed impact, collision and friction of the supersonic airflow, the coal slime or sludge particles are further crushed.

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