Pretreatment device for sludge incineration

Abstract

The utility model provides a pretreatment device for sludge incineration, which relates to the technical field of solid waste and is characterized in that a sludge inlet end of a drying machine is communicated with a wet sludge pipeline, an exhaust port of the drying machine is connected with a drying tail gas treatment component, and a sludge outlet end of the drying machine and a discharge port of a limestone powder conveying component are both communicated with a feed port of a mixing conveyor; a discharge port of the mixing conveyor is communicated with a mill, a discharge port of the mill is provided with a bin pump, and the bin pump is communicated to a feeding port of an incinerator; the output end of the drying tail gas treatment assembly communicates with a bin pump and is used for pneumatic conveying, one path of outlet flue gas of the incinerator communicates with a flue gas purification assembly, the other path of outlet flue gas of the incinerator communicates with a mill, and the technical problems that in the prior art, condensation and moisture absorption occur, the flue gas adheres to a conveying belt, and a conveying route is large in limitation and limited in arrangement are solved. The technical effects that the drying tail gas serves as a pneumatic conveying gas source, and the limestone and the semi-dry sludge are mixed, so that moisture regain, viscosity increase and pipeline blockage are avoided are achieved.

Description

Technical Field

[0001] This utility model relates to the technical field of solid waste treatment devices, and in particular to a pretreatment device for sludge incineration. Background Technology

[0002] Sludge incineration is a commonly used and relatively thorough method for sludge disposal. Most sludge comes from dewatered wastewater treatment plants, and depending on the dewatering process, it typically has two moisture contents: 80% and 60%. Sludge with a 60% moisture content, due to its lower water content, can be fed directly into the incinerator without drying. However, sludge with a 80% moisture content, due to its higher water content, usually needs to be dried first before incineration. Sludge with a 80% moisture content is first dried to a semi-dry state with a moisture content between 30% and 40% through indirect thermal drying. At this point, the sludge is in a semi-dry state, appearing as unevenly distributed granules of 3cm to 5cm.

[0003] In existing sludge pretreatment equipment, semi-dry sludge is mainly transported directly to the sludge incinerator via belts, scrapers, or transport vehicles.

[0004] This transportation method requires a large area, has limited transport routes and layout, and involves high investment. In addition, the initial temperature of dried sludge is relatively high, between 90℃ and 100℃, which makes it prone to condensation and moisture absorption during transportation, leading to stickiness and adhesion to the conveyor belt. In severe cases, it can even cause blockages, affecting subsequent processes of sludge incineration and reducing the efficiency and stability of the entire treatment process. Utility Model Content

[0005] The purpose of this invention is to provide a pretreatment device for sludge incineration, so as to alleviate the technical problems existing in the prior art, such as condensation and moisture absorption, sticking to the conveyor belt, and large limitations in conveying routes and layout.

[0006] The present invention provides a pretreatment device for sludge incineration, comprising: a dryer, a dryer exhaust gas treatment component, a mixing conveyor, a limestone powder conveying component, a mill, a silo pump, and an incinerator;

[0007] The sludge inlet of the dryer is connected to the wet sludge pipeline, the exhaust port of the dryer is connected to the drying tail gas treatment component, the sludge outlet of the dryer and the discharge port of the limestone powder conveying component are both connected to the inlet of the mixing conveyor, the discharge port of the mixing conveyor is connected to the mill, the discharge port of the mill is equipped with a silo pump, and the silo pump is connected to the feeding port of the incinerator.

[0008] The output of the drying tail gas treatment component is connected to the silo pump for pneumatic conveying. One path of the flue gas from the incinerator's outlet is connected to the flue gas purification component, and the other path of the flue gas from the incinerator's outlet is connected to the mill.

[0009] Furthermore, the exhaust port of the mill is connected to the air inlet of the incinerator.

[0010] Furthermore, the exhaust gas drying treatment assembly includes an exhaust gas dust collector, an exhaust gas condenser, and an exhaust gas fan arranged sequentially along the exhaust gas flow direction; the exhaust gas fan is connected to the chamber pump.

[0011] Furthermore, the drying machine can be a disc drying machine, a paddle drying machine, a thin-layer drying machine, or a belt drying machine.

[0012] Furthermore, the sludge moisture content of the sludge connected to the wet sludge pipe at the sludge inlet end of the dryer is 75%–80%, and the sludge moisture content of the sludge at the sludge outlet end of the dryer is 30%–40%.

[0013] Furthermore, the mixing conveyor is a twin-shaft screw conveyor or a single-shaft screw conveyor, with helical blades on its surface to drive the sludge and limestone to mix and transport to the mill.

[0014] Furthermore, the mill is a vertical mill, ball mill, or roller press, and the particle size of the ground particles is 50μm to 200μm.

[0015] Furthermore, a flow monitor is installed on the conveying pipeline between the silo pump and the incinerator. The flow monitor is used to monitor the flow rate of the material in the conveying pipeline.

[0016] Beneficial effects:

[0017] The pretreatment device for sludge incineration provided by this utility model includes: the sludge inlet end of the dryer is connected to a wet sludge pipeline; the exhaust port of the dryer is connected to a drying tail gas treatment component; the sludge outlet end of the dryer and the discharge port of the limestone powder conveying component are both connected to the inlet of a mixing conveyor; the discharge port of the mixing conveyor is connected to a mill; a silo pump is installed at the discharge port of the mill; the silo pump is connected to the feeding port of the incinerator; the output end of the drying tail gas treatment component is connected to the silo pump for pneumatic conveying; one path of the flue gas outlet of the incinerator is connected to a flue gas purification component; and another path of the flue gas outlet of the incinerator is connected to the mill.

[0018] By adding limestone and mixing it with dried sludge, condensation moisture can be absorbed, preventing the semi-dry sludge from becoming damp during transportation; the sludge clumping structure can be broken down, reducing sludge viscosity; and when sent into the high-temperature zone of the incinerator, it can play a role in in-furnace desulfurization, reducing the amount of limestone added to the incinerator.

[0019] By utilizing flue gas as drying hot air within the mill, there is no need to add a separate hot air furnace, reducing costs and improving heat utilization. The dried flue gas, carrying some dried sludge and limestone powder, is returned to the incinerator for high-temperature treatment, ensuring complete combustion of pollutants and reducing pollution.

[0020] Compared to conventional scraper or belt conveyors, which have limited conveying distance and routes and are difficult to select in complex environments, pneumatic conveying provides uniform delivery and, through pipelines, can adapt to various complex installation environments. Fine particles entering the furnace also burn more quickly, improving combustion efficiency. Using dried exhaust gas as the conveying gas source reduces the amount of compressed air needed and does not increase the amount of air entering the incinerator, thus increasing the incinerator's thermal efficiency. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 A schematic diagram of the pretreatment device for sludge incineration provided in an embodiment of this utility model.

[0023] Icons: 1 - Dryer; 2 - Drying exhaust gas treatment assembly; 201 - Exhaust gas dust collector; 202 - Exhaust gas condenser; 203 - Exhaust gas fan; 3 - Mixing conveyor; 4 - Limestone powder conveying assembly; 5 - Mill; 6 - Silo pump; 601 - Flow monitor; 7 - Incinerator; 8 - Flue gas purification assembly. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0029] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0030] The following detailed description, in conjunction with the accompanying drawings, outlines some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0031] like Figure 1 As shown, this utility model embodiment provides a pretreatment device for sludge incineration, including: a dryer 1, a dryer exhaust gas treatment component 2, a mixing conveyor 3, a limestone powder conveying component 4, a mill 5, a silo pump 6, and an incinerator 7.

[0032] The sludge inlet of the dryer 1 is connected to the wet sludge pipe, the exhaust port of the dryer 1 is connected to the drying tail gas treatment component 2, the sludge outlet of the dryer 1 and the discharge port of the limestone powder conveying component 4 are both connected to the inlet of the mixing conveyor 3, the discharge port of the mixing conveyor 3 is connected to the mill 5, the discharge port of the mill 5 is equipped with a silo pump 6, and the silo pump 6 is connected to the feeding port of the incinerator 7.

[0033] The output end of the drying tail gas treatment component 2 is connected to the silo pump 6 for pneumatic conveying. One path of the flue gas outlet of the incinerator 7 is connected to the flue gas purification component 8, and the other path of the flue gas outlet of the incinerator 7 is connected to the mill 5.

[0034] Specifically, the sludge inlet of the dryer 1 is connected to a wet sludge pipeline, which transports sludge with a high moisture content into the dryer 1. The dryer 1 is a conventional, existing dryer, and includes a heating device and a stirring device inside. Heat is transferred to the wet sludge through heat transfer, causing the moisture to evaporate. The stirring device ensures that the wet sludge is heated evenly during the drying process, improving drying efficiency. The exhaust port of the dryer 1 is connected to the drying exhaust gas treatment component 2. The exhaust gas generated during the drying process, containing water vapor, volatile organic compounds, and a small amount of dust, enters the drying exhaust gas treatment component 2 through the exhaust port for treatment. The treated clean exhaust gas is then transported from the output end of the drying exhaust gas treatment component 2 to the silo pump 6 through the exhaust gas conveying device, providing power for the pneumatic conveying of the silo pump 6 and realizing the reuse of the exhaust gas.

[0035] The sludge outlet of the dryer 1 is connected to the inlet of the mixing conveyor 3. After drying, the semi-dry sludge with reduced moisture content is discharged from the outlet and enters the mixing conveyor 3. The mixing conveyor 3 has two inlets: one connected to the outlet of the dryer 1 to receive the dried sludge; the other connected to the outlet of the limestone powder conveying assembly 4 to receive limestone powder. The outlet of the mixing conveyor 3 is connected to the mill 5, conveying the mixed material to the mill 5. This invention adds limestone powder during the conveying process: firstly, it absorbs condensed moisture, preventing the sludge from becoming damp during transport; secondly, the limestone particles are fully mixed with the semi-dry sludge particles, breaking down the sludge's clump structure and reducing its viscosity; and thirdly, the added limestone is sent to the high-temperature zone of the incinerator along with the sludge, serving as an in-furnace desulfurization agent and reducing the amount of limestone required for incineration.

[0036] Mill 5 receives the mixed material from mixing conveyor 3. Mill 5 consists of a grinding device (i.e., grinding rollers and grinding disc), where the material is ground into powder between the rollers and disc. The grinding device is moved by the rotation of the grinding disc, which in turn drives the grinding rollers. The grinding pressure, in addition to the weight of the rollers, is mainly applied to the material on the grinding disc by a hydraulic system. Simultaneously, mill 5 is connected to the outlet flue gas of incinerator 7, and the high-temperature flue gas discharged from incinerator 7 enters mill 5. This high-temperature flue gas provides a drying heat source for the material inside mill 5, further reducing its moisture content. Furthermore, the flow of the high-temperature flue gas helps to carry the ground fine particles out of mill 5 and into silo pump 6. Silo pump 6 is funnel-shaped and located at the outlet of mill 5. Silo pump 6 is connected to the output end of drying tail gas treatment component 2, using the treated drying tail gas as the power source for pneumatic conveying. Once the material in the silo pump 6 reaches a certain amount, the material will be pneumatically conveyed through a pipeline to the feeding port of the incinerator 7.

[0037] The mixed material delivered by the silo pump 6 enters the incinerator 7 through the feed inlet. The incinerator 7 maintains a high-temperature environment, ensuring complete combustion of organic matter in the sludge and releasing heat. The flue gas from the incinerator 7 is split into two paths: one connects to the flue gas purification component 8, and the other connects to the mill 5. The mill 5 uses the flue gas from the incinerator 7 as drying hot air, effectively utilizing the heat of the flue gas without the need for an additional hot air furnace, reducing costs and improving heat utilization. The dried flue gas, carrying some dried sludge / limestone powder, returns to the incinerator for high-temperature treatment, ensuring complete combustion of pollutants and reducing pollution.

[0038] This invention employs pneumatic conveying after grinding in the dryer 1. Semi-dry sludge, due to its viscosity and non-flowability, is typically conveyed using scrapers or belts, which limits the conveying distance and route, making path selection difficult in complex environments. Direct pneumatic conveying of semi-dry sludge results in uneven sludge particle size and poor conveying efficiency. Furthermore, condensation and moisture return during transport increase viscosity, leading to blockages and hindering proper conveying.

[0039] The ground dry sludge and limestone mixture forms uniform, fine particles, making it ideal for pneumatic conveying. This ensures even transport and allows for pipeline transport, adapting to various complex installation environments. The fine particles also burn more quickly in incinerator 7, improving combustion efficiency. Hot air drying during the grinding process maintains the temperature of the dry sludge / limestone powder and further reduces its moisture content, preventing moisture absorption and stickiness during pneumatic conveying and avoiding pipe blockage.

[0040] The dried exhaust gas discharged from the output end of the dried exhaust gas treatment component 2 is used as a steam source for conveying gas. This exhaust gas is originally intended to be sent into the incinerator 7 as primary / secondary make-up air. In this invention, using it as a gas source for pneumatic conveying can reduce the amount of compressed air used, without increasing the amount of air entering the incinerator, thus increasing the thermal efficiency of the incinerator.

[0041] It should be noted that the silo pump 6 is a new type of pneumatic conveying equipment that combines jet technology and fluidization technology. When the material enters the pump body and the silo is full, it is vaporized to form a fluidized state and smoothly enters the mixing chamber. At the same time, compressed air is ejected at high speed through the jet nozzle and fully mixed with the fluidized material. The high-speed airflow carries the material through the Laval tube, converting the kinetic energy of the compressed air into pressure energy, and at the same time mixing the air and material again, increasing the speed of the material and making it move forward along the conveying pipeline to achieve the purpose of conveying powdered materials.

[0042] It should be noted that the flue gas purification assembly 8 internally includes a bag filter, a desulfurization tower, and a denitrification device. When the flue gas discharged from the incinerator 7 enters the flue gas purification assembly 8, the bag filter removes dust particles from the flue gas; the desulfurization tower removes sulfur dioxide from the flue gas by spraying alkaline solutions; and the denitrification device reduces the content of nitrogen oxides in the flue gas. After purification, the flue gas meets environmental emission standards and is then discharged into the atmosphere.

[0043] In an embodiment of this utility model, the exhaust port of the mill 5 is connected to the air inlet of the incinerator 7.

[0044] The drying exhaust gas treatment component 2 includes an exhaust gas dust collector 201, an exhaust gas condenser 202, and an exhaust gas fan 203 arranged sequentially along the exhaust gas flow direction; the exhaust gas fan 203 is connected to the chamber pump 6.

[0045] The drying machine 1 can be a disc drying machine, a paddle drying machine, a thin-layer drying machine, or a belt drying machine.

[0046] The sludge moisture content at the sludge inlet end of the dryer 1, which is connected to the wet sludge pipe, is 75%–80%, and the sludge moisture content at the sludge outlet end of the dryer 1 is 30%–40%.

[0047] Specifically, the mill 5 generates waste gas during the grinding and drying of the mixture, and its waste gas outlet is connected to the air inlet of the incinerator 7. The waste gas discharged from the mill 5 may contain a small amount of incompletely burned organic matter, dust, etc., which can be further burned in the high-temperature environment of the incinerator 7 after being introduced into it.

[0048] The exhaust gas discharged from the dryer 1 first enters the exhaust gas dust collector 201. The dust collector 201 can employ bag filters or cyclone separators to remove most of the dust particles from the exhaust gas, preventing dust from causing wear and blockage to subsequent equipment. Next, the exhaust gas enters the exhaust gas condenser 202, where it is cooled, and the water vapor condenses into liquid water and is discharged, thus reducing the humidity of the exhaust gas. Finally, the treated exhaust gas is transported to the silo pump 6 by the exhaust gas fan 203, providing power for the pneumatic conveying of the silo pump 6. This not only reduces pollutant emissions from the exhaust gas but also uses the treated exhaust gas as a power source for the pneumatic conveying of the silo pump 6, realizing the resource utilization of the exhaust gas and reducing energy consumption and operating costs.

[0049] It should be noted that the optimal method of this invention is to use sludge with a moisture content of 75% to 80% to achieve a semi-dry sludge moisture content of 30% to 40% through thermal drying. Of course, wet sludge with a moisture content of 60% or other moisture contents, which achieves a moisture content of 30% to 50% after drying, is also applicable.

[0050] In the embodiments of this utility model, the mixing conveyor 3 is a twin-shaft screw conveyor or a single-shaft screw conveyor. The surface of the mixing conveyor 3 is provided with helical blades for pushing the sludge and limestone to mix and convey to the mill 5.

[0051] Mill 5 is a vertical mill, ball mill, or roller press, and the particle size of the ground particles is 50μm to 200μm.

[0052] A flow monitor 601 is installed on the conveying pipeline between the silo pump 6 and the incinerator 7. The flow monitor 601 is used to monitor the flow rate of the material in the conveying pipeline.

[0053] Based on the above embodiments, the specific working process of the pretreatment device for sludge incineration provided by this utility model is as follows: wet sludge (initial moisture content 75% to 80%) enters the dryer 1 through the wet sludge pipeline. After drying treatment, the moisture content is reduced to 30% to 40%, forming semi-dry sludge. The exhaust gas generated during the drying process enters the drying exhaust gas treatment component 2 from the exhaust port of the dryer 1, and the treated drying exhaust gas is transported to the silo pump 6 as the gas source for subsequent pneumatic conveying.

[0054] At this point, the dried semi-dry sludge and limestone powder are thoroughly mixed by the mixing conveyor 3 and transported to the mill 5, where the mixture is ground. During this process, the high-temperature flue gas discharged from the incinerator 7 is introduced into the mill 5 through a pipeline as a drying heat source to perform secondary drying on the ground particles, reducing the moisture content and maintaining the temperature to prevent the material from absorbing moisture and becoming sticky again. The dried flue gas carries a small amount of powder back to the high-temperature zone of the incinerator 7 to ensure complete combustion of pollutants.

[0055] The ground mixture falls into the silo pump 6, which uses the air source provided by the drying exhaust gas treatment component 2 to pneumatically convey the material through pipelines to the feeding port of the incinerator 7. After entering the high-temperature zone of the incinerator 7, the mixture is fully combusted. The flue gas generated by combustion is treated by the flue gas purification component 8 to meet emission standards, and is also recycled as a drying heat source for the mill 5. In addition, the exhaust gas discharged from the mill 5 is connected to the air inlet of the incinerator 7 through the exhaust port, where unburned materials undergo secondary combustion within the incinerator 7, achieving dual recovery of heat and materials.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A pretreatment device for sludge incineration, characterized by comprising: The device comprises a dryer (1), a dryer tail gas treatment assembly (2), a mixing conveyor (3), a limestone powder conveying assembly (4), a mill (5), a bin pump (6) and an incinerator (7). The mud inlet end of the dryer (1) is connected to a wet sludge pipeline, the exhaust outlet of the dryer (1) is connected to the dryer tail gas treatment assembly (2), the mud outlet end of the dryer (1) and the discharge outlet of the limestone powder conveying assembly (4) are both connected to the feed inlet of the mixing conveyor (3), the discharge outlet of the mixing conveyor (3) is connected to the mill (5), the discharge outlet of the mill (5) is provided with the bin pump (6), and the bin pump (6) is connected to the feeding inlet of the incinerator (7). The output end of the dryer tail gas treatment assembly (2) is connected to the bin pump (6) for pneumatic conveying, and the outlet flue gas of the incinerator (7) is connected to a flue gas purification assembly (8) and the mill (5).

2. The sludge incineration pretreatment device according to claim 1, wherein the exhaust outlet of the mill (5) is connected to the air inlet of the incinerator (7).

3. The sludge incineration pretreatment device according to claim 1, wherein the dryer tail gas treatment assembly (2) comprises a tail gas dust remover (201), a tail gas condenser (202) and a tail gas fan (203) arranged in sequence along the tail gas flow direction, and the tail gas fan (203) is connected to the bin pump (6).

4. The sludge incineration pretreatment device according to claim 1, wherein the dryer (1) is a disc dryer, a paddle dryer, a thin-layer dryer or a belt dryer.

5. The sludge incineration pretreatment device according to claim 4, wherein the sludge humidity of the wet sludge pipeline connected to the mud inlet end of the dryer (1) is 75%-80%, and the sludge humidity of the mud outlet end of the dryer (1) is 30%-40%.

6. The sludge incineration pretreatment device according to claim 1, wherein the mixing conveyor (3) is a double-shaft screw conveyor or a single-shaft screw conveyor, and the surface of the mixing conveyor (3) is provided with spiral blades for pushing the sludge and limestone to mix and be conveyed to the mill (5).

7. The sludge incineration pretreatment device according to claim 1, wherein the mill (5) is a vertical mill, a ball mill or a roller press, and the particle size of the ground particles is 50-200 μm.

8. The sludge incineration pretreatment device according to claim 1, wherein a flow monitor (601) is arranged on the conveying pipeline between the bin pump (6) and the incinerator (7), and the flow monitor (601) is used for monitoring the flow of the materials in the conveying pipeline. ​ ​ ​ ​ ​ ​ ​ ​

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