A system and method for direct incineration of sludge with high moisture content

Abstract

This invention discloses a system and method for direct incineration of high-moisture-content sludge, including a high-moisture-content sludge direct incineration device, a flue gas heat exchanger, a blower, flue gas treatment equipment, an induced draft fan, and a chimney. The high-moisture-content sludge direct incineration device includes a multi-pass rotating device and a settling chamber. In this system, the sludge is dried in the first pass, pyrolyzed in the second pass, and burned in the third pass. High-temperature air serves as the heat source for sludge drying and also as the combustion air during sludge incineration. This device is the core of the system, integrating multiple sludge disposal processes into one, resulting in a relatively simple and easy-to-control system. The high-moisture-content sludge direct incineration device in this system can effectively dry, pyrolyze, and incinerate sludge. The exhaust gas generated during drying is also treated during incineration, eliminating the need for separate treatment lines.

Description

Technical Field

[0001] This invention relates to the field of sludge drying and treatment technology, and in particular to a system and method for direct incineration of sludge with high moisture content. Background Technology

[0002] With economic development and the improvement of people's living standards, the urbanization process is accelerating, leading to a significant increase in the amount of industrial and domestic wastewater generated, and consequently, a growing volume of sludge. In response, the government strongly supports sludge reduction and incineration technologies, with incineration technology seeing substantial development and widespread application.

[0003] Direct co-firing of wet sludge for power generation involves feeding wet sludge directly into a power plant boiler and co-firing it with coal. Drying and co-firing of sludge for power generation involves drying the wet sludge before feeding it into the power plant boiler and co-firing it with coal. Both methods utilize existing power plant boilers to co-fire sludge and coal, releasing heat to generate steam for turbine generators to produce electricity.

[0004] In the direct co-firing scheme, sludge needs to be mixed with coal in a certain proportion, which limits the processing capacity. In the drying co-firing scheme, new drying process equipment is required, and both schemes rely on power plants.

[0005] Compared with the high-moisture-content sludge direct incineration system involved in this invention, the direct co-firing of wet sludge from power plants has the following problems:

[0006] Excessive moisture content: The moisture content of wet sludge is usually above 80%, which makes the transportation, storage, and treatment of sludge difficult. If the moisture content is too low, the sludge will easily clump together, affecting the incineration efficiency.

[0007] Unstable combustion: Wet sludge contains a large amount of organic matter and moisture. These substances are easily volatilized and decomposed at high temperatures, leading to unstable combustion and the generation of harmful gases such as carbon dioxide, which affects air quality and the environment.

[0008] High processing costs: Sludge processing costs are high, including costs associated with collection, transportation, storage, incineration, and post-treatment. These costs need to be deducted from the power plant's electricity generation or heating revenue, which may have a certain impact on the company's economic benefits. Summary of the Invention

[0009] To address the aforementioned problems, this invention proposes a direct incineration system and method for high-moisture-content sludge, which can maximize economic savings and minimize energy consumption.

[0010] The direct incineration system for high-moisture sludge has the following advantages:

[0011] Incineration can significantly reduce the volume and mass of sludge, with the final incineration product volume reduced by 85%–95% and the mass reduced by 70%–80%.

[0012] Incineration can completely destroy harmful substances such as organic matter, pathogens, and heavy metals in sludge, thereby achieving the goal of eliminating pollution.

[0013] The ash residue produced after sludge incineration can be utilized as a resource, further reducing the pressure of sludge treatment.

[0014] The hot flue gas generated by high-temperature combustion can be used to heat the ambient air through a flue gas heat exchanger, which is then used to dry wet sludge, reducing the energy consumption cost of sludge treatment.

[0015] The incineration unit integrates three systems—sludge drying, sludge pyrolysis, and sludge incineration—through multiple passes. It is mainly designed for the treatment of sludge with high water content. Compared to building three separate systems, it features high integration and high processing efficiency.

[0016] The stirring device and the inner wall threads can effectively increase the contact area between the sludge and hot air during the drying, pyrolysis and combustion processes in the current return stroke, which is beneficial for moisture removal, volatile matter release and improved combustion efficiency.

[0017] The incineration system no longer depends on the construction of power plants, the site selection is more flexible, and the processing capacity is no longer limited by the co-firing ratio of power plants. It can be designed and constructed according to actual needs.

[0018] To achieve the above objectives, the technical solution of the present invention is as follows:

[0019] A high-moisture-content sludge direct incineration system includes a high-moisture-content sludge direct incineration device, a flue gas heat exchanger, a flue gas treatment process equipment, an induced draft fan, and a chimney connected in series. The flue gas heat exchanger is also connected to the blower.

[0020] The high-moisture-content sludge direct incineration device includes a multi-pass rotating device, which comprises a first cylinder, a second cylinder, and a third cylinder. Each of the first, second, and third cylinders has an outlet on one side. The third cylinder is fixedly connected to the inside of the second cylinder, and the second cylinder is fixedly connected to the inside of the first cylinder. A rotation drive device is provided below the outside of the first cylinder. The drive end of the rotation drive device is connected to a gear, which is sleeved on the periphery of the first cylinder. Multiple tires are also sleeved on the periphery of the first cylinder, and the first cylinder is rotatably connected to a bracket through the multiple tires.

[0021] Multiple first annular scrapers are fixedly connected to the side wall of the first cylinder, and multiple second annular scrapers are fixedly connected to the side wall of the second cylinder.

[0022] A bearing on one side of the first cylinder is connected to the inlet of high-moisture sludge and auxiliary fuel, and a bearing on one side of the inlet of high-moisture sludge and auxiliary fuel is connected to the third cylinder; an ignition device is also provided below the inlet of high-moisture sludge and auxiliary fuel and on the first cylinder.

[0023] The high-moisture-content sludge direct incineration device also includes a settling chamber, which is connected in series with the periphery of the first cylinder and located on the outlet side of the first cylinder;

[0024] The settling chamber has a high-temperature flue gas outlet at the top and a slag discharge port at the bottom.

[0025] Preferably, a stirring device is provided on one side of the settling chamber, and the driving end of the stirring device passes through the settling chamber and the second cylinder in sequence and extends into the third cylinder.

[0026] Preferably, a high-temperature air inlet is also provided on the high-moisture sludge and auxiliary fuel inlet.

[0027] Preferably, the flue gas heat exchanger is provided with a high-temperature flue gas inlet, a high-temperature air outlet, an ambient air inlet, and a low-temperature flue gas outlet from top to bottom. The high-temperature flue gas inlet is connected to the high-temperature flue gas outlet, the low-temperature flue gas outlet is connected to the flue gas treatment process equipment, the high-temperature air outlet is connected to the high-temperature air inlet, and the ambient air inlet is connected to the blower.

[0028] Preferably, the flue gas treatment process equipment includes an untreated flue gas inlet and a treated flue gas outlet, the low-temperature flue gas outlet is connected to the untreated flue gas inlet, and the treated flue gas outlet is connected to the induced draft fan.

[0029] Preferably, the first cylinder and the settling chamber are connected by a scale seal.

[0030] Preferably, the connecting pipes between the high-temperature flue gas outlet and the high-temperature flue gas inlet, the high-temperature air outlet and the high-temperature air inlet, and the low-temperature flue gas outlet and the untreated flue gas inlet are all insulated.

[0031] Preferably, both the blower and the induced draft fan are variable frequency fans.

[0032] Preferably, the periphery of the high-moisture-content sludge and auxiliary fuel inlet, the first cylinder, and the connection between the stirring device and the settling chamber are all sealed.

[0033] A method for direct incineration of sludge with high moisture content includes the following steps:

[0034] S1): Construct a direct incineration system for sludge with high moisture content;

[0035] S2): High-moisture-content sludge and auxiliary fuel are introduced through the high-moisture-content sludge and auxiliary fuel inlet. The high-moisture-content sludge and auxiliary fuel enter the third cylinder. The stirring device stirs the high-moisture-content sludge and auxiliary fuel. Then, the high-moisture-content sludge and auxiliary fuel enter the second cylinder. The second annular scraper on the second cylinder pushes the high-moisture-content sludge and auxiliary fuel to the outlet on one side of the second cylinder and flows to the first cylinder. The ignition device is activated, and the high-moisture-content sludge and auxiliary fuel burn in the first cylinder. At the same time, the first annular scraper on the first cylinder pushes the high-moisture-content sludge and auxiliary fuel to the outlet on one side of the first cylinder and enters the settling chamber. High-temperature gas enters the high-temperature flue gas inlet from the high-temperature flue gas outlet and heats the ambient air sent by the blower. The air that has absorbed heat enters the third cylinder of the multi-pass rotating device from the high-temperature flue gas outlet through the gas pipeline and the high-temperature air inlet. After the high-temperature gas releases heat, it enters the untreated flue gas inlet from the low-temperature flue gas outlet and enters the flue gas treatment process equipment. Then, the induced draft fan sends the treated flue gas to the chimney for discharge.

[0036] In summary, the high-moisture-content sludge direct incineration system and method disclosed in this invention has the following beneficial effects:

[0037] (1) The high moisture content sludge direct incineration device in this system can effectively dry, pyrolyze and incinerate the sludge. The exhaust gas generated during drying is also treated during incineration, so there is no need to set up a separate treatment line.

[0038] (2) The high-moisture sludge direct incineration device in this system integrates drying, pyrolysis and incineration, which significantly reduces the system equipment and floor space.

[0039] (3) The heat in the high-temperature flue gas is effectively absorbed by the flue gas heat exchanger in the system and used for front-end sludge drying and combustion support. The air volume can be changed by changing the fan speed to match the system requirements, so as to achieve the lowest operating energy consumption and the highest comprehensive benefits.

[0040] (4) By exhausting air through the induced draft fan, the system operates under negative pressure, and polluting gases are discharged in an organized manner, ensuring a clean environment. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the direct incineration system for high-moisture sludge in the embodiment.

[0042] Figure captions: Incineration unit 1; High moisture content sludge and auxiliary fuel inlet 11; Ash discharge port 12; High temperature air inlet 13; High temperature flue gas outlet 14; Multi-pass rotary device 15; First cylinder 151; Second cylinder 152; Third cylinder 153; Settling chamber 16; Ignition device 17; Rotary drive device 18; Stirring device 19; Flue gas heat exchanger 2; High temperature flue gas inlet 21; Low temperature flue gas outlet 22; Ambient air inlet 23; High temperature air outlet 24; Blower 3; Flue gas treatment process equipment 4; Untreated flue gas inlet 41; Treated flue gas outlet 42; Exhaust fan 5; Chimney 6. Detailed Implementation

[0043] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0044] like Figure 1 The high-moisture-content sludge direct incineration system shown includes: a high-moisture-content sludge direct incineration unit 1, a flue gas heat exchanger 2, a blower 3, flue gas treatment process equipment 4, an induced draft fan 5, a chimney 6, and necessary pipes and valves for the system.

[0045] The high-moisture-content sludge direct incineration device 1 includes a multi-pass rotating device 15 and a settling chamber 16. The multi-pass rotating device 15 has a high-moisture-content sludge and auxiliary fuel inlet 11, a high-temperature air inlet 13, an ignition device 17, a rotation drive device 18, and a stirring device 19. The settling chamber 16 has a slag discharge port 12 and a high-temperature flue gas outlet 14.

[0046] The rotary drive device 18 drives the multi-turn rotary device 15 to rotate via a large gear. In addition, the support roller supports the rotation of the multi-turn rotary device 15 via a tire. To ensure the normal operation of the equipment, a corresponding lubrication system is provided for the large gear. The multi-turn rotary device 15 and the settling chamber 16 are connected by a scale seal, and the ignition device 17 is connected to the multi-turn rotary device 15 in a sealed manner.

[0047] Insulation measures should be taken on the outside of the gas pipeline to reduce heat loss, improve heat utilization, and ensure that the temperature of the flue gas entering the equipment is within the high-efficiency operating range.

[0048] Both blower 3 and induced draft fan 5 are variable frequency fans. By changing the fan speed, the air volume is changed to match the system requirements, so as to achieve the lowest operating energy consumption and the highest overall efficiency.

[0049] The high-moisture-content sludge, auxiliary fuel, and high-temperature air mixing inlet is connected to the multi-pass rotating device 15 using an external seal and internal bearing connection. There are supports between the first and second passes, and between the second and third passes, and the rotational angular velocity is the same for each pass.

[0050] The stirring device 19 and the settling chamber 16 are connected by an external seal and an internal bearing connection. The stirring device 19 is driven by a motor and rotates in the opposite direction to the multi-pass rotating device 15, thereby extending the residence time of sludge and auxiliary fuel in the first pass.

[0051] The multi-pass rotating device 15 has an internal thread structure in the second and third passes, which prevents sludge, auxiliary fuel, pyrolysis process and combustion final products from sticking and prevents scale buildup on the surface.

[0052] The flue gas heat exchanger 2 has good internal tube sheet sealing, high finned heat pipe heat exchange efficiency, and is equipped with a shock wave soot blowing interface.

[0053] The flue gas treatment process equipment 4 can make the concentration of flue gas components reach or fall below the emission control requirements in GB18485-2014, and the flue gas is sent to the chimney 6 by the induced draft fan 5 for discharge.

[0054] The system works as follows:

[0055] High-moisture sludge and auxiliary fuel, and high-temperature air enter the multi-pass rotating device 15 through the high-moisture sludge and auxiliary fuel inlet 11 and the high-temperature air inlet 13, respectively, and sealing measures are in place to ensure isolation between the inside and outside of the device.

[0056] In the first pass of the multi-pass rotating device 15, high-moisture sludge, auxiliary fuel, and high-temperature air mix and come into contact. As the multi-pass rotating device 15 rotates, it moves towards the outlet of the first pass (i.e., the third cylinder 153). The high-temperature air releases heat, causing the moisture in the high-moisture sludge to evaporate and reducing its moisture content. To improve efficiency, the stirring device 19 in the first pass agitates the sludge and auxiliary fuel, increasing the residence time and allowing for more thorough mixing and contact with the high-temperature air in the first pass.

[0057] Sludge and auxiliary fuel enter the second pass (i.e., the second cylinder 152) from the first pass. The inner wall of the second pass is arranged with threads. As the multi-pass rotating device 15 rotates, it pushes the sludge and auxiliary fuel mixture toward the outlet of the second pass. In the second pass, the sludge with a low water content undergoes pyrolysis, and volatiles are also released at the same time.

[0058] Sludge and auxiliary fuel enter the third pass (i.e., the first cylinder 151) from the second pass. Ignition device 17 ignites the mixture of sludge and auxiliary fuel. With the help of high-temperature air, it burns in the third pass. The inner wall of the third pass is also arranged with threads in an orderly manner. As the multi-pass rotating device 15 rotates, it pushes the sludge, auxiliary fuel and combustion products toward the outlet of the third pass.

[0059] Combustion products are divided into burnt residue and high-temperature flue gas. The burnt residue is discharged from the slag discharge port 12, and the high-temperature flue gas enters the flue gas heat exchanger 2 from the high-temperature flue gas outlet 14 through the gas pipeline and the high-temperature flue gas inlet 21.

[0060] The high-temperature flue gas is exposed to ambient air supplied by the blower 3 in the flue gas heat exchanger 2. The high-temperature air, after absorbing heat, enters the multi-pass rotating device 15 from the high-temperature flue gas outlet 24 through the gas pipeline and the high-temperature air inlet 13. The low-temperature flue gas, after releasing heat, enters the flue gas treatment process equipment 4 from the low-temperature flue gas outlet 22 through the gas pipeline and the untreated flue gas inlet 41. Then, the treated flue gas is sent to the chimney 6 for discharge by the induced draft fan 5.

[0061] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method for direct incineration of sludge with high moisture content, characterized in that, The system is based on a high moisture content sludge direct incineration device (1), a flue gas heat exchanger (2), a flue gas treatment process equipment (4), an induced draft fan (5), and a chimney (6) connected in series. The flue gas heat exchanger (2) is also connected to the blower (3). The high-moisture-content sludge direct incineration device (1) includes a multi-pass rotating device (15); the inner wall of the multi-pass rotating device (15) is arranged with threads, and while the multi-pass rotating device (15) rotates, it pushes the sludge and auxiliary fuel mixture toward the outlet of the multi-pass rotating device (15); the multi-pass rotating device (15) includes a first cylinder (151), a second cylinder (152) and a third cylinder (153), and each of the first cylinder (151), the second cylinder (152) and the third cylinder (153) has an outlet on one side. The third cylinder (153) is fixedly connected to the inside of the second cylinder (152), and the second cylinder (152) is fixedly connected to the inside of the first cylinder (151). A rotation drive device (18) is provided on the lower outside of the first cylinder (151). A gear is connected to the drive end of the rotation drive device (18). The gear is sleeved on the periphery of the first cylinder (151). Multiple tires are also sleeved on the periphery of the first cylinder (151). The first cylinder (151) is rotatably connected to the bracket through the multiple tires. Multiple first annular scrapers are fixedly connected to the side wall of the first cylinder (151), and multiple second annular scrapers are fixedly connected to the side wall of the second cylinder (152). A bearing on one side of the first cylinder (151) is connected to a high moisture content sludge and auxiliary fuel inlet (11), and a bearing on one side of the high moisture content sludge and auxiliary fuel inlet (11) is connected to the third cylinder (153); an ignition device (17) is also provided below the high moisture content sludge and auxiliary fuel inlet (11) and on the first cylinder (151). The high moisture content sludge direct incineration device (1) further includes a settling chamber (16), which is connected in series to the periphery of the first cylinder (151) and located on the outlet side of the first cylinder (151). The settling chamber (16) is provided with a high-temperature flue gas outlet (14) at the top and a slag discharge port (12) at the bottom. The method includes the following steps: S1): Construct a direct incineration system for sludge with high moisture content; S2): High-moisture-content sludge and auxiliary fuel are introduced from the high-moisture-content sludge and auxiliary fuel inlet (11). The high-moisture-content sludge and auxiliary fuel enter the third cylinder (153). The stirring device (19) stirs the high-moisture-content sludge and auxiliary fuel. Then, the high-moisture-content sludge and auxiliary fuel enter the second cylinder (152). The second annular scraper on the second cylinder (152) pushes the high-moisture-content sludge and auxiliary fuel to the outlet on one side of the second cylinder (152) and flows to the first cylinder (151). The ignition device (17) is activated, and the high-moisture-content sludge and auxiliary fuel burn in the first cylinder (151). At the same time, the first cylinder (151) is filled with sludge and auxiliary fuel. The first annular scraper pushes the high-moisture sludge and auxiliary fuel to the outlet on one side of the first cylinder (151) and into the settling chamber (16). The high-temperature gas enters the high-temperature flue gas inlet (21) from the high-temperature flue gas outlet (14) and heats the ambient air sent by the blower (3). The heated air enters the third cylinder (153) of the multi-pass rotating device (15) from the high-temperature flue gas outlet (24) through the gas pipe and the high-temperature air inlet (13). After the high-temperature gas releases heat, the low-temperature flue gas outlet (22) enters the untreated flue gas inlet (41) and enters the flue gas treatment process equipment (4). The treated flue gas is then sent to the chimney (6) by the induced draft fan (5) for discharge.

2. The method for direct incineration of high-moisture-content sludge as described in claim 1, characterized in that, A stirring device (19) is provided on one side of the settling chamber (16). The driving end of the stirring device (19) passes through the settling chamber (16) and the second cylinder (152) in sequence and extends into the third cylinder (153).

3. The method for direct incineration of high-moisture-content sludge as described in claim 2, characterized in that, A high-temperature air inlet (13) is also provided on the high-moisture sludge and auxiliary fuel inlet (11).

4. The method for direct incineration of high-moisture-content sludge as described in claim 3, characterized in that, The flue gas heat exchanger (2) is provided with a high-temperature flue gas inlet (21), a high-temperature air outlet (24), an ambient air inlet (23), and a low-temperature flue gas outlet (22) from top to bottom. The high-temperature flue gas inlet (21) is connected to the high-temperature flue gas outlet (14), the low-temperature flue gas outlet (22) is connected to the flue gas treatment process equipment (4), the high-temperature air outlet (24) is connected to the high-temperature air inlet (13), and the ambient air inlet (23) is connected to the blower (3).

5. The method for direct incineration of high-moisture-content sludge as described in claim 4, characterized in that, The flue gas treatment process equipment (4) includes an untreated flue gas inlet (41) and a treated flue gas outlet (42). The low-temperature flue gas outlet (22) is connected to the untreated flue gas inlet (41), and the treated flue gas outlet (42) is connected to the induced draft fan (5).

6. The method for direct incineration of high-moisture-content sludge as described in claim 5, characterized in that, The first cylinder (151) and the settling chamber (16) are connected by a scale seal.

7. The method for direct incineration of high-moisture-content sludge as described in claim 6, characterized in that, The connecting pipes between the high-temperature flue gas outlet (14) and the high-temperature flue gas inlet (21), the high-temperature air outlet (24) and the high-temperature air inlet (13), and the low-temperature flue gas outlet (22) and the untreated flue gas inlet (41) are all insulated.

8. The method for direct incineration of high-moisture-content sludge as described in claim 7, characterized in that, Both the blower (3) and the induced draft fan (5) are variable frequency fans.

9. A method for direct incineration of high-moisture-content sludge as described in claim 8, characterized in that, The periphery of the high moisture content sludge and auxiliary fuel inlet (11), the first cylinder (151), the connection between the stirring device (19) and the settling chamber (16) is sealed.

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