A circulating fluidized bed integrated sludge incineration system

Abstract

The present invention discloses an incinerator, a separator, a pneumatic distribution valve, a dryer, a fine ash separator, a condenser, a steam-water separator, a first blower, a rear heating surface, a dust collector, an induced draft fan, and a chimney; the upper part of the incinerator is respectively connected to the separator and the rear heating surface; the lower part of the separator is respectively connected to the incinerator and the dryer through a pneumatic distribution valve, and the dried sludge in the dryer passes through the fine ash separator, the condenser, and the steam-water separator in turn, and is sent to the incinerator under the action of the first blower; the rear heating surface is connected to the dryer through circulating heat transfer oil, and the high-temperature flue gas in the rear heating surface passes through the dust collector and is discharged from the chimney under the action of the induced draft fan. The present invention organically integrates sludge drying and incineration, greatly reduces the consumption of auxiliary fuel during sludge incineration, greatly simplifies the drying and incineration process, and has the characteristics of simple operation, large adjustment range, good control performance, and low production cost.

Description

Technical Field

[0001] The invention relates to the technical field of sludge incineration, and more specifically to a circulating fluidized bed integrated sludge incineration system. Background Art

[0002] As the population of our country continues to increase, secondary pollution from sewage sludge follows. Since there are organic pollutants, heavy metals, parasites, pathogens, and corrosive substances in sludge, if it is not properly handled, it will seriously affect the ecological environment. Under normal circumstances, sludge treatment mainly includes reclamation, landfill, incineration, land use and other forms. However, in recent years, as the country has gradually restricted sludge composting and landfilling, and prohibited the dumping of sludge into the sea, the main method of sludge treatment today is incineration. Incineration can carbonize organic matter in sludge, completely kill pathogens, minimize the volume of sludge, and greatly reduce the impact of sludge on the ecological environment.

[0003] Sludge drying can effectively reduce the volume of sludge, usually by more than 4 times, and produce stable, sterile, and odorless raw materials. The dried sludge products are widely used, not only as fertilizers, soil conditioners, etc., but also as a substitute for some energy. Sludge drying equipment can be divided into two forms: direct heating and indirect heating according to the medium and contact method. Sludge incineration needs to be carried out at a very high temperature. In an environment with sufficient oxygen, the organic matter in the sludge is burned and converted into gases such as nitrogen dioxide, carbon dioxide, and water vapor. The main products of incineration are flue gas and ash. Incineration treatment technology can decompose all organic matter, completely kill pathogens, improve the stability of heavy metals, and the volume of sludge after incineration is only 1 / 10 of the volume of mechanically dehydrated sludge. However, sludge drying and incineration are inseparable and carried out separately. Not only are there many equipment and high energy consumption, but also large sites and high processing costs. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the defects of the above-mentioned prior art sludge drying and incineration, the purpose of the present invention is to organically integrate sludge drying and incineration, greatly reduce the consumption of auxiliary fuel during sludge incineration, simplify the drying and incineration process, and provide a circulating fluidized bed integrated sludge incineration system.

[0006] (II) Technical solution

[0007] A circulating fluidized bed integrated sludge incineration system comprises an incinerator, a separator, a pneumatic distribution valve, a dryer, a fine ash separator, a condenser, a steam-water separator, a first blower, a rear heating surface, a dust collector, an induced draft fan, and a chimney; the upper part of the incinerator is respectively connected to the separator and the rear heating surface; the lower part of the separator is respectively connected to the incinerator and the dryer through a pneumatic distribution valve, the dried sludge in the dryer passes through the fine ash separator, the condenser, and the steam-water separator in turn, and is sent to the incinerator under the action of the first blower; the rear heating surface is connected to the dryer through circulating heat transfer oil, and the high-temperature flue gas in the rear heating surface passes through the dust collector and is discharged from the chimney under the action of the induced draft fan.

[0008] According to an embodiment of the present invention, the separator is a cyclone separator.

[0009] According to an embodiment of the present invention, the dust collector is a bag dust collector.

[0010] According to one embodiment of the present invention, the left and right ends of the pneumatic distribution valve are respectively equipped with a circulating ash entering incinerator ash pipe and a circulating ash entering dryer ash pipe, the circulating ash entering incinerator ash pipe is connected to the incinerator, and the circulating ash entering dryer ash pipe is connected to the dryer; the lower part of the pneumatic distribution valve is respectively provided with return air zone I, return air zone II, return air zone III, and return air zone IV from left to right, the circulating ash entering return air zone I enters the incinerator through the circulating ash entering incinerator ash pipe, the return air zone II and return air zone III control the fluidization of the circulating ash by the air volume, and the circulating ash entering the return air zone IV enters the dryer through the circulating ash entering dryer ash pipe.

[0011] According to one embodiment of the present invention, a discharge pipe is installed above the return air zone I of the pneumatic distribution valve.

[0012] According to one embodiment of the present invention, a hole is opened 100 mm above the side of the return air zone I and a pipe with a diameter of Φ32 mm is installed by welding.

[0013] According to one embodiment of the present invention, a heat exchange device is installed in the middle of the discharge pipe.

[0014] According to one embodiment of the present invention, a partition is installed between the return air zone II and the return air zone III of the pneumatic distribution valve 4. The height of the partition is 200 mm, and the inclination angle of the partition to and from the return air zone II is 5°.

[0015] According to one embodiment of the present invention, a pressure balancing pipe is connected between the ash pipe for circulating ash to enter the incinerator and the ash pipe for circulating ash to enter the dryer.

[0016] (III) Beneficial effects

[0017] The technical solution of the present invention is adopted, a circulating fluidized bed integrated sludge incineration system, which organically integrates sludge drying and incineration, greatly reduces the consumption of auxiliary fuel during sludge incineration, greatly simplifies the drying and incineration process, has the characteristics of simple operation, large adjustment range, good control performance, low production cost, etc., and can achieve safe, stable, continuous and economical operation; a discharge pipe is installed above the return air zone I of the pneumatic distribution valve to allow excess circulating ash to be discharged from the system through the discharge pipe, which can adjust the balance of materials, increase combustion intensity, increase operating load, and prevent return termination failure rate; the return air zone II and return air zone of the pneumatic distribution valve A partition is installed between the material and air zones III to divert the circulating ash in advance and avoid being affected by the wind pressure of the incinerator and the dryer. The circulating ash is forced to go to the dryer without being affected by the wind pressure on both sides, thereby increasing the amount of circulating ash returned to the dryer, allowing high-temperature materials to go to the dryer to dry the sludge and increase the sludge processing capacity. A pressure balance pipe is connected between the ash pipe for the circulating ash to enter the incinerator and the ash pipe for the circulating ash to enter the dryer to avoid the uneven pressure affecting the return effect of the circulating ash, ensure the pressure and material regulating function of the circulating ash in the furnace, keep the furnace balanced, prevent the cyclone separator from returning and causing blockage and coking, and ensure that the furnace outlet temperature meets the design requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the present invention, the same reference numerals refer to the same features throughout, wherein:

[0019] Figure 1 This is the schematic diagram of the sludge incineration system;

[0020] Figure 2 This is a schematic diagram of the pneumatic distribution valve structure.

[0021] Description of reference numerals:

[0022] 1. Auxiliary fuel; 2. Incinerator; 3. Cyclone separator; 4. Pneumatic distribution valve; 5. Dryer; 6. Fine ash separator; 7. Condenser; 8. Steam-water separator; 9. First blower; 10. Rear heating surface; 11. Second blower; 12. Dust collector; 13. Induced draft fan; 14. Chimney; 15. Air preheater inlet; 16. Heating oil pipe; 401. Circulating ash enters the ash pipe of the incinerator; 402. Circulating ash enters the ash pipe of the dryer; 403. Return air zone I; 404. Return air zone II; 405. Return air zone III; 406. Return air zone IV; 407. Discharge pipe; 408. Heat exchange device; 409. Partition; 410. Pressure balance pipe. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0024] Combination Figure 1A circulating fluidized bed integrated sludge incineration system includes an auxiliary fuel 1, an incinerator 2, a separator 3, a pneumatic distribution valve 4, a dryer 5, a fine ash separator 6, a condenser 7, a steam-water separator 8, a first blower 9, a rear heating surface 10, a second blower 11, a dust collector 12, an induced draft fan 13, a chimney 14, and a heat transfer oil 16.

[0025] The upper part of the incinerator 2 is connected to the separator 3 and the tail heating surface 10 respectively; the lower part of the separator 3 is connected to the incinerator 2 and the dryer 5 respectively through the pneumatic distribution valve 4. The dried sludge in the dryer 5 passes through the fine ash separator 6, the condenser 7, and the steam-water separator 8 in turn, and is sent to the incinerator 2 under the action of the first blower 9; the tail heating surface 10 is connected to the dryer 5 through the circulating heat transfer oil 16, and the high-temperature flue gas in the tail heating surface 10 passes through the dust collector 12 and is discharged from the chimney 14 under the action of the induced draft fan 13. The auxiliary fuel 1 is sent to the incinerator 2 through the conveyor belt. Part of the flue gas in the tail heating surface 10 is sent to the furnace of the incinerator 2 through the second blower 11. The air preheater incoming material 15 enters the incinerator through the bottom of the incinerator 2. The separator 3 is a cyclone separator. The dust collector 12 is a bag dust collector.

[0026] The dry sludge after the wet sludge is dried by the dryer directly enters the incinerator for combustion. The heat generated after combustion consists of two parts; a part of the high-temperature flue gas generated after the dry sludge is burned enters the tail heating surface to heat the heat transfer oil, and the heat generated by the heat transfer oil is used to dry the wet sludge in the dryer; the other part of the high-temperature hot ash generated after the dry sludge is burned passes through the cyclone separator and enters the pneumatic distribution valve, which is divided into two ways by the pneumatic distribution valve and enters the incinerator and the dryer respectively. The circulating ash is distributed to the incinerator and the dryer at 79% and 21% respectively.

[0027] Pneumatic distribution valves undergo great changes in actual applications and are affected by many other factors: they are greatly affected by the disturbance of the two pressure winds of the fluidized bed boiler and the dryer. Because the pressure control of the fluidized bed dryer requires a complete set of pressure control points, the valve operation and adjustment are difficult; in addition, the combustion situation of a circulating fluidized bed incinerator is relatively complicated. The circulating fluidized bed boiler itself does not have high requirements for fuel, but has particularly high requirements for the control of the wind system. For example, the incinerator has 5 materials entering the furnace: a. dry sludge from the dryer; b. oil guns under the bed and on the bed; c. fuel for the fine air separator; d. coal and kaolin; e. lime spray calcium desulfurization. The furnace is greatly affected by other uncertain winds under hot conditions, and the operation is quite difficult. It is difficult to find the balance point, so the requirements for the operation and operation personnel are particularly high, and it is affected by factors such as large fluctuations in the furnace pressure.

[0028] In order to meet the process requirements during actual operation and avoid frequent return termination or coking failure of the cyclone separator 3, the pneumatic distribution valve 4 includes a circulating ash entering the incinerator ash pipe 401, a circulating ash entering the dryer ash pipe 402, a return air zone I 403, a return air zone II 404, a return air zone III 405, a return air zone IV 406, a discharge pipe 407, a heat exchange device 408, a partition 409, and a pressure balance pipe 410.

[0029] The left and right ends of the pneumatic distribution valve 4 are respectively equipped with a circulating ash entering the incinerator ash pipe 401 and a circulating ash entering the dryer ash pipe 402. The circulating ash entering the incinerator ash pipe 401 is connected to the incinerator, and the circulating ash entering the dryer ash pipe 402 is connected to the dryer; the lower part of the pneumatic distribution valve 4 is respectively provided with a return air zone I 403, a return air zone II 404, a return air zone III 405, and a return air zone IV 406 from left to right. The circulating ash entering the return air zone I 403 enters the incinerator through the circulating ash entering incinerator ash pipe 401, the return air zone II 404 and the return air zone III 405 control the circulating ash fluidization through the air volume, and the circulating ash entering the return air zone IV 406 enters the dryer through the circulating ash entering the dryer ash pipe 402.

[0030] Circulating ash is the hot ash after sludge combustion in the circulating fluidized bed incinerator. The circulating ash temperature reaches 850℃. This medium is used as a heat transfer medium in the circulating fluidized bed boiler. This heat is used to directly enter the dryer to dry the sludge. The sludge drying process is first mixed with hot ash. The presence of a large amount of circulating ash strengthens the sludge drying rate and avoids local high-temperature combustion of hot ash and sludge. The circulating ash is sent to the incinerator through the air volume of the return air zone Ⅰ 403; the circulating ash enters the space of the return air zone Ⅱ 404 and the return air zone Ⅲ 405 of the pneumatic distribution valve, and the air volume of the return air zone Ⅱ 404 and the return air zone Ⅲ 405 controls the fluidization of the circulating ash; the circulating ash is sent to the dryer through the air volume of the return air zone Ⅳ 406.

[0031] In order to balance the pressure difference of the incinerator, adjust the balance of materials, increase the combustion intensity, improve the operating load, and prevent the failure rate of return material termination, a discharge pipe 407 is installed above the return air zone I 403 of the pneumatic distribution valve to allow excess circulating ash to be discharged from the system through the discharge pipe. A Φ32mm diameter pipe is welded and installed at 100mm above the side of the return air zone I 403. The pipe goes directly to the 0-meter layer to discharge the material through the variable frequency screw machine. A heat exchange device 408 is installed in the middle of the discharge pipe to prevent the hot ash from burning the spiral.

[0032] In order to divert the circulating ash in advance and avoid the influence of the wind pressure of the incinerator and the dryer, and to force the circulating ash to the dryer without being affected by the wind pressure on both sides, increase the amount of circulating ash returned to the dryer, and allow high-temperature materials to go to the dryer to dry the sludge, thereby increasing the sludge processing capacity, a partition is installed between the return air zone II 404 and the return air zone III 405 of the pneumatic distribution valve 4. The height of the partition is 200mm, and the inclination angle of the partition to and from the return air zone II 404 is 5°.

[0033] Since the incinerator and dryer on both sides of the pneumatic distribution valve 4 are two independently balanced systems, in order to avoid uneven pressure affecting the circulating ash return effect, a pressure balance pipe 410 is connected between the circulating ash entering the incinerator ash pipe 401 and the circulating ash entering the dryer ash pipe 402.

[0034] The present invention is implemented in a sewage treatment plant in Hangzhou, with a sludge treatment flow of 106 tons / day, a furnace outlet temperature of 874 degrees (designed 850 degrees), a temperature on both sides of the pneumatic distribution valve, a furnace side of 854 degrees, a dryer side of 799 and 759 degrees; the operating temperature and processing capacity have reached the design requirements, ensuring the pressure and material regulation of the circulating ash in the furnace, keeping the furnace balanced, preventing the cyclone separator from returning material and causing blockage and coking, thereby ensuring that the furnace outlet temperature reaches the design requirements. Tested by the National Environmental Protection Agency, the operating emission index dioxin: toxic equivalent (TEQ) mass concentration value is 0.01ng / m3, the national standard is 1ng / m3, and all other emission indicators are in full compliance with the national standard.

[0035] In summary, the technical solution of the present invention is adopted. The circulating fluidized bed integrated sludge incineration system of the embodiment of the present invention organically integrates sludge drying and incineration, greatly reduces the consumption of auxiliary fuel during sludge incineration, greatly simplifies the drying and incineration process, and has the characteristics of simple operation, large adjustment range, good control performance, low production cost, etc., and can achieve safe, stable, continuous and economical operation; a discharge pipe is installed above the return air zone I of the pneumatic distribution valve to allow excess circulating ash to be discharged from the system through the discharge pipe, which can adjust the balance of materials, increase combustion intensity, increase operating load, and prevent the return termination failure rate; the return of the pneumatic distribution valve A partition is installed between wind zone II and return air zone III to divert the circulating ash in advance to avoid being affected by the wind pressure of the incinerator and the dryer. The circulating ash is forced to go to the dryer without being affected by the wind pressure on both sides, thereby increasing the amount of circulating ash returned to the dryer, allowing high-temperature materials to go to the dryer to dry the sludge and increase the sludge processing capacity. A pressure balance pipe is connected between the ash pipe for circulating ash to enter the incinerator and the ash pipe for circulating ash to enter the dryer to avoid the uneven pressure affecting the return effect of the circulating ash, ensure the pressure and material regulation of the circulating ash in the furnace, keep the furnace balanced, prevent the cyclone separator from returning and causing blockage and coking, thereby ensuring that the furnace outlet temperature meets the design requirements.

[0036] Those skilled in the art should recognize that the above embodiments are only used to illustrate the purpose of the present invention, and are not intended to limit the present invention. As long as they are within the spirit and scope of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A circulating fluidized bed integrated sludge incineration system, characterized by: It includes an incinerator, a separator, a pneumatic distribution valve, a dryer, a fine ash separator, a condenser, a steam-water separator, a first blower, a rear heating surface, a dust collector, an induced draft fan, and a chimney; the upper part of the incinerator is respectively connected to the separator and the rear heating surface; the lower part of the separator is respectively connected to the incinerator and the dryer through a pneumatic distribution valve, and the dried sludge in the dryer passes through the fine ash separator, the condenser, and the steam-water separator in turn, and is sent to the incinerator under the action of the first blower; the rear heating surface is connected to the dryer through circulating heat transfer oil, and the high-temperature flue gas in the rear heating surface passes through the dust collector and is discharged from the chimney under the action of the induced draft fan. The left and right ends of the pneumatic distribution valve are respectively equipped with a circulating ash entering the incinerator ash pipe and a circulating ash entering the dryer ash pipe. The circulating ash entering the incinerator ash pipe is connected to the incinerator, and the circulating ash entering the dryer ash pipe is connected to the dryer. The lower part of the pneumatic distribution valve is respectively provided with return air zone I, return air zone II, return air zone III, and return air zone IV from left to right. The circulating ash entering the return air zone I enters the incinerator through the circulating ash entering the incinerator ash pipe. The return air zones II and III control the fluidization of the circulating ash through the air volume. The circulating ash entering the return air zone IV enters the dryer through the circulating ash entering the dryer ash pipe. A discharge pipe is installed above the return air zone I of the pneumatic distribution valve to balance the pressure difference of the incinerator, adjust the balance of materials, increase the combustion intensity, increase the operating load, and prevent the return termination failure rate. A Φ32mm diameter pipe is welded and installed at a hole 100mm above the side of the return air zone I. The pipe is directly discharged to the 0-meter layer through the variable frequency screw machine. A partition is installed between the return air zone II and the return air zone III of the pneumatic distribution valve. The height of the partition is 200mm, and the partition is inclined at an angle of 5° to the return air zone II, so that the circulating ash can be diverted in advance to avoid being affected by the wind pressure of the incinerator and the dryer. The circulating ash is forced to be sent to the dryer without being affected by the wind pressure on both sides, increasing the amount of circulating ash returned to the dryer, allowing high-temperature materials to dry sludge in the dryer, and increasing the sludge treatment capacity. A pressure balance pipe is connected between the ash pipe for circulating ash to enter the incinerator and the ash pipe for circulating ash to enter the dryer, so as to avoid the influence of uneven pressure on the return effect of circulating ash.

2. A circulating fluidized bed integrated sludge incineration system as claimed in claim 1, characterized in that: The separator is a cyclone separator.

3. The circulating fluidized bed integrated sludge incineration system according to claim 1, characterized in that: The dust collector is a bag dust collector.

4. The circulating fluidized bed integrated sludge incineration system according to claim 1, characterized in that: A heat exchange device is installed in the middle of the discharge pipe.

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