System device and system method for directly blending and burning high-water-content sludge

Abstract

The application provides a system device and a system method for directly mixing and burning high-water-content sludge, which comprises a circulating fluidized bed device and a sludge feeding assembly. The sludge feeding assembly comprises a sludge storage device and a sludge feeding device connected in sequence. A sludge outlet of the sludge feeding device is connected with a sludge inlet at the top of the circulating fluidized bed device through a sludge feeding pipeline. The sludge storage device is connected with an air extraction assembly. The air extraction assembly comprises an air extraction device. A gas inlet of the air extraction device is connected with a gas outlet of the sludge storage device. A gas outlet of the air extraction assembly is arranged on the sludge feeding pipeline. The system device and the system method can reduce high-temperature oxidation corrosion of the sludge falling pipeline, prolong the service life of the wet sludge falling pipeline, increase the rigidity of the wet sludge sent into the furnace, and effectively alleviate the contamination of the heating surface after the high-water-content sludge directly enters the furnace.

Description

Technical Field

[0001] This invention belongs to the field of sludge treatment and relates to a system device and method for sludge co-firing, specifically a system device and method for direct co-firing of sludge with high water content. Background Technology

[0002] The rapid development of the social economy, accelerated urbanization, and improved living standards have led to a sharp increase in urban sewage volume. As a byproduct of sewage treatment plants, sludge production is also rising. In 2020, China's dry sludge production reached 14.595 million tons, with 13.946 million tons disposed of. Sludge incineration is the most thorough sludge treatment method, offering fast processing speed, high volume reduction, and energy reuse, making it a relatively feasible approach. Circulating fluidized bed boilers, with their wide fuel adaptability, have become the preferred technology for co-processing sludge in coal-fired power units.

[0003] The dewatered sludge from wastewater treatment plants typically has a high moisture content, generally between 75% and 85%. The conventional technical solution for directly co-firing high-moisture-content sludge (75%–85%) in circulating fluidized bed boilers involves directly pumping the sludge to the top of the circulating fluidized bed boiler using a plunger pump, and then allowing it to enter the furnace for drying and incineration through a newly added discharge port. The main problems with this approach are: high-moisture-content sludge dries very easily in the high-temperature environment inside the furnace; after drying, the sludge easily adheres and clogs the discharge port, or adheres to the upper heating surfaces of the furnace, exacerbating fouling and reducing heat exchange efficiency; and without co-firing, the high-temperature environment of the furnace intensifies high-temperature oxidation and corrosion of the discharge pipe, shortening its service life. Summary of the Invention

[0004] To address the technical problems existing in the prior art, the present invention provides a system device and method for direct co-firing of sludge with high moisture content. The system device and method can reduce the high-temperature oxidation and corrosion of the feed pipe and extend the service life of the wet sludge feed pipe; it can also increase the rigidity of the wet sludge fed into the furnace and effectively alleviate the fouling phenomenon of the heated surface after the high moisture content sludge directly enters the furnace.

[0005] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0006] One objective of this invention is to provide a system device for direct co-firing of high moisture content sludge. The system device includes a circulating fluidized bed device and a sludge feeding assembly. The sludge feeding assembly includes a sludge storage device and a sludge feeding device connected in sequence. The sludge outlet of the sludge feeding device is connected to the sludge inlet at the top of the circulating fluidized bed device through a sludge feeding pipeline.

[0007] The sludge storage device is connected to an air extraction assembly, which includes an air extraction device. The gas inlet of the air extraction device is connected to the gas outlet of the sludge storage device. The gas outlet of the air extraction assembly is located in the sludge feeding pipeline. The air extraction device is connected to the gas outlet of the air extraction assembly through a pipeline.

[0008] In this invention, during the operation of the high-moisture-content sludge direct co-firing system, an exhaust assembly is used to use the exhaust gas from the sludge storage device as the perimeter air of the high-moisture-content sludge inlet injection device. The perimeter air can cool the sludge feeding pipeline arranged near the furnace and increase the rigidity of the wet sludge fed into the furnace, ensuring that the wet sludge dries quickly in the area away from the heating surface, effectively alleviating the contamination of the heating surface after the high-moisture-content sludge directly enters the furnace.

[0009] In this invention, the air extraction device can be a negative pressure air extraction device.

[0010] As a preferred technical solution of the present invention, the air extraction component includes at least a first gas outlet, a second gas outlet and a third gas outlet, the first gas outlet is connected to the gas inlet of the circulating fluidized bed device, and the second gas outlet and the third gas outlet are disposed in the sludge feeding pipeline.

[0011] As a preferred technical solution of the present invention, a first valve is provided on the pipeline connecting the gas outlet of the extraction device and the first gas outlet;

[0012] A second valve is installed on the pipeline connecting the gas outlet of the extraction device to the second gas outlet and the third gas outlet.

[0013] As a preferred embodiment of the present invention, a third valve and a fourth valve are independently provided on the pipelines connecting the second valve to the second gas outlet and the third gas outlet, respectively.

[0014] As a preferred technical solution of the present invention, the air extraction assembly further includes a secondary air device, the gas outlet of which is connected to the second gas outlet and the third gas outlet via a pipeline.

[0015] As a preferred embodiment of the present invention, a fifth valve is provided on the secondary air device, the second gas outlet, and the third gas connection pipeline.

[0016] In this invention, when the exhaust device needs maintenance, the peripheral air is supplied through the secondary air device to ensure the reliable and safe operation of the system. When the high moisture content direct co-firing system is shut down, the boiler-side sludge feed valve is closed, and some of the exhaust gas is sent from a location away from the high-temperature area of ​​the boiler to the sludge conveying pipeline. This serves two purposes: firstly, it cleans the high moisture content sludge, preventing it from adhering to the wall after a long period of shutdown and affecting the next startup of the sludge direct co-firing system; secondly, it cools the inner wall of the sludge conveying pipeline in the high-temperature area of ​​the furnace, improving the protection of the sludge conveying pipeline in the high-temperature area of ​​the boiler.

[0017] In this invention, the first valve, the second valve, the third valve, the fourth valve, and the fifth valve are each independently a pneumatic valve;

[0018] As a preferred embodiment of the present invention, the system device includes a fuel feeding assembly, which includes a fuel storage device and a fuel feeding device connected in sequence, and the fuel outlet of the fuel feeding device is connected to the fuel inlet of the circulating fluidized bed device.

[0019] As a preferred embodiment of the present invention, the gas outlet of the circulating fluidized bed device is connected to a gas processing component.

[0020] In this invention, the gas treatment assembly may include a cyclone dust collector, a heat exchanger, an air preheater, an environmental protection island, and a chimney connected in sequence; wherein, the gas inlet of the cyclone dust collector is connected to the gas outlet of the circulating fluidized bed device, and the solid outlet of the cyclone dust collector is connected to the solid inlet of the circulating fluidized bed device.

[0021] The second objective of this invention is to provide a system method for the direct co-firing of high-moisture-content sludge, wherein the system method uses any of the above-mentioned system devices, and the system method includes:

[0022] The sludge feeding device sends sludge from the sludge storage device into the circulating fluidized bed device for co-firing.

[0023] The extraction device extracts the gas from the sludge storage device and delivers it through the gas outlet of the extraction component to the sludge feeding pipeline as perimeter ventilation.

[0024] As a preferred technical solution of the present invention, when the air extraction device stops, the secondary air device delivers air from the gas outlet of the air extraction component to the sludge feeding pipeline as perimeter air.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] (1) The present invention provides a system device and system method for direct co-firing of high moisture content sludge. The system device and system method send the waste gas in the sludge storage device to the sludge conveying pipeline and send it together with the sludge into the top position of the circulating fluidized bed furnace. This can reduce the high temperature oxidation corrosion of the discharge pipe and extend the service life of the wet sludge discharge pipe. It can also increase the rigidity of the wet sludge fed into the furnace and effectively alleviate the contamination of the heating surface after the high moisture content sludge directly enters the furnace.

[0027] (2) The present invention provides a system device and system method for direct co-firing of sludge with high water content. When the exhaust device stops working, the system device and system method can use boiler secondary air to replace the exhaust gas, so as to continuously ensure the safe and reliable operation of the system.

[0028] (3) The present invention provides a system device and system method for direct co-firing of sludge with high moisture content. After the co-firing system stops running, the system device and system method can continue to run the air extraction system. On the one hand, it is used to flush the sludge to prevent the problem of blockage of the conveying pipe when the system is restarted due to the sludge adhering to the inner wall. On the other hand, it can cool the inner wall of the sludge conveying pipe in the high temperature area of ​​the furnace and improve the protection of the sludge conveying pipe in the high temperature area of ​​the boiler side. Attached Figure Description

[0029] Figure 1 A schematic diagram of the system device for direct co-firing of high moisture content sludge provided for a specific embodiment of the present invention;

[0030] In the diagram: 1-Coal bunker, 2-Coal feeder, 3-Sludge storage bunker, 4-Sludge variable frequency vibrating feeder, 5-Negative pressure exhaust device, 6-First valve, 7-Second valve, 8-Third valve, 9-Fourth valve, 10-Fifth valve, 11-Secondary air fan, 12-Circulating fluidized bed boiler, 13-Cyclone dust collector, 14-Heat exchanger, 15-Air preheater, 16-Environmental protection island, 17-Chimney.

[0031] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0032] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0033] One specific embodiment of the present invention provides a system device for direct co-firing of high moisture content sludge. The system device includes a circulating fluidized bed device and a sludge feeding assembly. The sludge feeding assembly includes a sludge storage device and a sludge feeding device connected in sequence. The sludge outlet of the sludge feeding device is connected to the sludge inlet at the top of the circulating fluidized bed device through a sludge feeding pipeline.

[0034] The sludge storage device is connected to an air extraction assembly, which includes an air extraction device. The gas inlet of the air extraction device is connected to the gas outlet of the sludge storage device. The gas outlet of the air extraction assembly is located in the sludge feeding pipeline. The air extraction device is connected to the gas outlet of the air extraction assembly through a pipeline.

[0035] The air extraction assembly includes at least a first gas outlet, a second gas outlet, and a third gas outlet. The first gas outlet is connected to the gas inlet of the circulating fluidized bed device, and the second and third gas outlets are located in the sludge feeding pipeline.

[0036] A first valve is installed on the pipeline connecting the gas outlet of the extraction device to the first gas outlet; a second valve is installed on the pipeline connecting the gas outlet of the extraction device to the second gas outlet and the third gas outlet; a third valve and a fourth valve are independently installed on the pipeline connecting the second valve to the second gas outlet and the third gas outlet, respectively.

[0037] The extraction assembly also includes a secondary air device, the gas outlet of which is connected to the second gas outlet and the third gas outlet via a pipeline; a fifth valve is provided on the pipeline connecting the secondary air device to the second gas outlet and the third gas outlet.

[0038] The system includes a fuel feeding assembly, which includes a fuel storage device and a fuel feeding device connected in sequence. The fuel outlet of the fuel feeding device is connected to the fuel inlet of the circulating fluidized bed device.

[0039] The gas outlet of the circulating fluidized bed device is connected to a gas processing component.

[0040] In one specific embodiment of the present invention, the system device closes the second valve, the third valve, the fourth valve, and the fifth valve, and opens the first valve. The air extraction system sends the gas in the sludge storage device into the circulating fluidized bed device for co-firing.

[0041] In one specific embodiment of the present invention, the system device closes the first valve and the fifth valve, and opens the second valve, the third valve and the fourth valve. The air extraction system sends the gas in the sludge storage device into the sludge feeding pipeline as perimeter air.

[0042] In one specific embodiment of the present invention, when the air extraction device in the system device stops operating, the secondary air device is turned on, the first valve and the second valve are closed, and the fifth valve, the third valve and the fourth valve are turned on. The secondary air device delivers air from the gas outlet of the air extraction component to the sludge feeding pipeline as perimeter air.

[0043] In one specific embodiment of the present invention, when the co-firing system is shut down, the sludge feeding assembly is closed, and the exhaust device continues to send exhaust gas to the sludge feeding pipeline. On the one hand, this washes away the sludge with high water content, preventing the sludge from adhering to the wall after a long period of shutdown, which would affect the next startup of the sludge direct co-firing system. On the other hand, it cools the inner wall of the sludge conveying pipeline in the high-temperature area of ​​the furnace, improving the protection of the sludge conveying pipeline in the high-temperature area of ​​the boiler side.

[0044] Example 1

[0045] This embodiment provides a system device for direct co-firing of high-moisture-content sludge, the structure of which is as follows: Figure 1 As shown, the system includes a circulating fluidized bed boiler 12 and a sludge feeding assembly. The sludge feeding assembly includes a sludge storage bin 3 and a sludge variable frequency vibrating feeder 4 connected in sequence. The sludge outlet of the sludge variable frequency vibrating feeder 4 is connected to the sludge inlet at the top of the circulating fluidized bed boiler 12 through a sludge feeding pipeline.

[0046] The sludge storage bin 3 is connected to an air extraction assembly, which includes a negative pressure air extraction device 5. The gas inlet of the negative pressure air extraction device 5 is connected to the gas outlet of the sludge storage bin 3. The gas outlet of the air extraction assembly is located in the sludge feeding pipeline. The negative pressure air extraction device 5 is connected to the gas outlet of the air extraction assembly through a pipeline.

[0047] The air extraction assembly includes at least a first gas outlet, a second gas outlet, and a third gas outlet. The first gas outlet is connected to the gas inlet of the circulating fluidized bed boiler 12, and the second gas outlet and the third gas outlet are located in the sludge feeding pipeline.

[0048] A first valve 6 is provided on the pipeline connecting the gas outlet of the negative pressure extraction device 5 to the first gas outlet; a second valve 7 is provided on the pipeline connecting the gas outlet of the negative pressure extraction device 5 to the second gas outlet and the third gas outlet; a third valve 8 and a fourth valve 9 are independently provided on the pipeline connecting the second valve 7 to the second gas outlet and the third gas outlet, respectively.

[0049] The extraction assembly also includes a secondary fan 11, the gas outlet of which is connected to the second gas outlet and the third gas outlet via a pipeline; a fifth valve 10 is provided on the secondary air device and the pipeline connecting the second gas outlet and the third gas outlet.

[0050] The first valve 6, the second valve 7, the third valve 8, the fourth valve 9, and the fifth valve 10 are each independently a pneumatic valve;

[0051] The system includes a fuel feeding assembly, which includes a coal bunker 1 and a coal feeder 2 connected in sequence. The fuel outlet of the coal feeder 2 is connected to the fuel inlet of the circulating fluidized bed boiler 12.

[0052] The gas outlet of the circulating fluidized bed boiler 12 is connected to a gas treatment assembly, which may include a cyclone dust collector 13, a heat exchanger 14, an air preheater 15, an environmental protection island 16, and a chimney 17 connected in sequence. The gas inlet of the cyclone dust collector 13 is connected to the gas outlet of the circulating fluidized bed boiler 12, and the solid outlet of the cyclone dust collector 13 is connected to the solid inlet of the circulating fluidized bed boiler 12.

[0053] Comparative Example 1

[0054] This comparative example provides a system device for direct co-firing of high moisture content sludge. Except for the absence of an air extraction component, the system device is identical to that in Example 1.

[0055] Application Example 1

[0056] This application example provides a system method for direct co-firing of high-moisture-content sludge. The system method uses the system apparatus provided in Example 1, and the system method includes:

[0057] The sludge variable frequency vibrating feeder 4 feeds sludge from the sludge storage bin 3 into the circulating fluidized bed boiler 12 through the top sludge inlet for co-firing;

[0058] When the first valve 6 and the fifth valve 10 are closed, and the second valve 7, the third valve 8 and the fourth valve 9 are opened, the negative pressure exhaust device 5 extracts the gas from the sludge storage bin 3 and delivers it to the sludge feeding pipeline as a perimeter airflow through the gas outlet of the exhaust assembly.

[0059] The coal feeder 2 delivers coal from the coal bunker 1 into the circulating fluidized bed boiler 12 for co-firing;

[0060] The gas generated by the circulating fluidized bed boiler 12 is processed sequentially by a cyclone dust collector 13, a heat exchanger 14, an air preheater 15, and an environmental protection island 16 before being discharged through a chimney 17.

[0061] Application Example 2

[0062] This application example provides a system method for direct co-firing of high-moisture-content sludge. The system method uses the system apparatus provided in Example 1, and the system method includes:

[0063] The second valve 7, the third valve 8, the fourth valve 9, and the fifth valve 10 are closed, and the first valve 6 is opened. The negative pressure exhaust device 5 sends the gas in the sludge storage bin 3 into the circulating fluidized bed boiler 12 for co-firing. All other conditions are the same as in Application Example 1.

[0064] Application Example 3

[0065] This application example provides a system method for direct co-firing of high-moisture-content sludge. The system method uses the system apparatus provided in Example 1, and the system method includes:

[0066] When the negative pressure extraction device 5 stops operating, the secondary fan 11 is turned on, the first valve 6 and the second valve 7 are closed, and the fifth valve 10, the third valve 8 and the fourth valve 9 are opened. The secondary fan 11 delivers air from the gas outlet of the extraction component to the sludge feeding pipeline as perimeter air. All other conditions are the same as in Application Example 1.

[0067] Comparative Application Example 1

[0068] The direct co-firing method for moisture-content sludge provided in this comparative application example uses the system apparatus provided in Comparative Example 1, and all other conditions are the same as in Application Example 1.

[0069] Compared with Comparative Application Example 1, the odorous cold air extracted by the extraction component in Application Example 1 can be used to cool the sludge conveying pipe in the high-temperature area of ​​the furnace, effectively reducing the high-temperature oxidation and corrosion of the discharge pipe and extending the service life of the wet sludge discharge pipe; it can also increase the rigidity of the wet sludge fed into the furnace, ensuring that the wet sludge dries quickly in the area away from the heating surface, effectively alleviating the contamination of the heating surface after the high moisture content sludge directly enters the furnace.

[0070] The applicant declares that the detailed structural features of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components selected in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0071] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0072] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0073] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A system for directly mixing and burning high water content sludge, characterized by comprising: The system includes a circulating fluidized bed device and a sludge feeding assembly. The sludge feeding assembly includes a sludge storage device and a sludge feeding device connected in sequence. The sludge outlet of the sludge feeding device is connected to the sludge inlet at the top of the circulating fluidized bed device through a sludge feeding pipeline. The sludge storage device is connected to an air extraction assembly, which includes an air extraction device. The gas inlet of the air extraction device is connected to the gas outlet of the sludge storage device. The gas outlet of the air extraction assembly is located in the sludge feeding pipeline. The air extraction device is connected to the gas outlet of the air extraction assembly through a pipeline. The air extraction assembly includes at least a first gas outlet, a second gas outlet, and a third gas outlet. The first gas outlet is connected to the gas inlet of the circulating fluidized bed device, and the second gas outlet and the third gas outlet are located in the sludge feeding pipeline.

2. The system for directly incinerating high-moisture sludge according to claim 1, wherein A first valve is installed on the pipeline connecting the gas outlet of the extraction device to the first gas outlet. A second valve is installed on the pipeline connecting the gas outlet of the extraction device to the second gas outlet and the third gas outlet.

3. The system for directly incinerating high-moisture sludge according to claim 2, wherein The pipelines connecting the second valve to the second gas outlet and the third gas outlet are each equipped with a third valve and a fourth valve, respectively.

4. The system for direct injection of high-moisture sludge according to claim 1, wherein The extraction assembly also includes a secondary air device, the gas outlet of which is connected to the second gas outlet and the third gas outlet via a pipeline.

5. The system for directly incinerating high-moisture sludge according to claim 4, wherein A fifth valve is installed on the secondary air device, the second gas outlet, and the third gas connection pipeline.

6. The system for direct injection of high-moisture-content sludge according to claim 1, wherein The system includes a fuel feeding assembly, which comprises a fuel storage device and a fuel feeding device connected in sequence. The fuel outlet of the fuel feeding device is connected to the fuel inlet of the circulating fluidized bed device.

7. The system apparatus for direct co-firing of high-moisture-content sludge according to claim 1, characterized in that, The gas outlet of the circulating fluidized bed device is connected to a gas processing component.

8. A systematic method for direct co-firing of high-moisture-content sludge, characterized in that, The system method uses the system apparatus according to any one of claims 1-7, and the system method comprises: The sludge feeding device sends sludge from the sludge storage device into the circulating fluidized bed device for co-firing. The extraction device extracts the gas from the sludge storage device and delivers it through the gas outlet of the extraction component to the sludge feeding pipeline as perimeter ventilation.

9. The system method for direct co-firing of high-moisture-content sludge according to claim 8, characterized in that, When the extraction device stops, the secondary air device delivers air from the gas outlet of the extraction component to the sludge feed pipeline as perimeter air.

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