Dry sludge bin dehumidification device

Abstract

The invention discloses a dehumidification device for a dry sludge bin. The dehumidification device comprises a hot air system, a dehumidification system and a tail gas treatment system which are connected in sequence, the hot air system is used for forming hot dry air; the tail gas treatment system is used for treating tail gas; the dehumidification system comprises a hot dry air pipe, an air distribution pipe, a dry sludge bin and a hot wet air pipe, the air distribution pipe is located at the bottom of the dry sludge bin, and a plurality of air injection holes are formed in the air distribution pipe; hot dry air enters the air distribution pipe located at the bottom of the dry sludge bin through the hot dry air pipe, flows out through the air injection holes in the air distribution pipe and penetrates through gaps between dry sludge in the dry sludge bin to take away moisture in the dry sludge, meanwhile, the hot dry air becomes hot wet air, the hot wet air enters the hot wet air pipe, and then the tail gas treatment system is used for treatment. According to the technical scheme, the moisture content of the dry sludge can be further removed by 5-20%.

Description

Technical Field

[0001] The present invention relates to the technical field of municipal sewage treatment, and more particularly to a dry sludge silo dehumidification device. Background Art

[0002] At present, the residual sludge generated by municipal sewage treatment plants usually has a moisture content of 30%-60% after mechanical deep dehydration (such as high-pressure plate and frame, high-pressure belt machine, vertical press, etc.) or thermal drying (direct thermal drying or indirect thermal drying). It is then transported to the dry sludge silo for storage through a conveying screw or scraper, and regularly unloaded to a transport vehicle for final disposal.

[0003] The residence time of dry sludge in storage silos is typically one to two days, which is considerably longer than the tens of minutes to two hours required by upstream dewatering / drying equipment. This extended residence time can be utilized to further dehumidify the dry sludge, thereby reducing the moisture content of the sludge discharged from upstream dewatering or drying units, thereby lowering operating costs or increasing production.

[0004] In addition, municipal sewage treatment plants are generally equipped with a blower room, in which multiple blowers are installed to supply oxygen to the biochemical treatment unit. Since the blowers have a large power, the heat dissipated by the blowers will cause the temperature in the blower room to rise. Usually, the heat is carried out of the blower room by convection through axial flow fans, and this part of the heat is basically wasted.

[0005] If the lost heat can be collected and a new technical means can be used to effectively dehumidify the dry sludge in the storage silo, the operating costs will be greatly reduced. Summary of the Invention

[0006] 1. Technical problem to be solved by the invention

[0007] In view of this, the object of the present invention is to provide a dry sludge silo dehumidification device, which arranges an air distribution pipe at the bottom of the dry sludge silo so that hot dry air flows upward along the gaps in the dry sludge, taking away the moisture in the dry sludge and completing further dehumidification of the interfering sludge.

[0008] 2. Technical solution

[0009] A dry sludge silo dehumidification device of the present invention comprises a hot air system, a dehumidification system and an exhaust gas treatment system connected in sequence;

[0010] The hot air system is used to generate hot dry air;

[0011] The tail gas treatment system is used to treat tail gas;

[0012] The dehumidification system includes a hot dry air pipe, an air distribution pipe, a dry sludge silo and a hot wet air pipe. The air distribution pipe is located at the bottom of the dry sludge silo and is provided with a plurality of air injection holes.

[0013] The hot dry air enters the air distribution pipe at the bottom of the dry sludge silo through the hot dry air pipe, flows out through the air jet holes on the air distribution pipe, passes through the gaps between the dry sludge in the dry sludge silo, and takes away the moisture in the dry sludge. At the same time, the hot dry air becomes hot wet air, enters the hot wet air pipe, and is then treated by the exhaust gas treatment system.

[0014] Furthermore, the air injection hole is located on the lower side of the air distribution pipe.

[0015] Furthermore, the plurality of air injection holes on the air distribution pipe are evenly distributed on the air distribution pipe.

[0016] Furthermore, perforated pipes are installed on the several jet holes on the air distribution pipe, the bottom of the perforated pipe is communicated with the jet holes, and the top of the perforated pipe is open. Hot dry air flows into the perforated pipe through the several jet holes on the air distribution pipe, flows out from the top opening of the perforated pipe, and then passes through the gaps between the dry sludge.

[0017] Furthermore, a filter is provided on the top of the dry sludge silo, and the hot and wet air is filtered by the filter and then enters the hot and wet air duct.

[0018] Furthermore, the air distribution duct is located 300 mm to 500 mm above the arch-breaking slide of the dry sludge silo.

[0019] Furthermore, one end of the air distribution pipe is connected to the hot dry air pipe, and the other end of the air distribution pipe is closed.

[0020] Furthermore, the hot air system comprises an air inlet box, a dust removal filter box, a heat exchanger and an air supply box connected in sequence;

[0021] The cold air enters the air inlet of the air inlet box, passes through the dust removal filter box to filter the dust, enters the heat exchanger to be heated to become hot dry air, and then enters the hot dry air duct from the air outlet after being pressurized by the air supply box.

[0022] Furthermore, the cold dry air is heated by a heat exchanger using hot water from a waste heat heat pump or hot air from a blower room in the factory.

[0023] Furthermore, the tail gas treatment system is a factory deodorization system.

[0024] 3. Beneficial effects

[0025] A dry sludge silo dehumidification device of the present invention comprises a hot air system, a dehumidification system and an exhaust gas treatment system connected in sequence; the hot air system is used to form hot dry air; the exhaust gas treatment system is used to treat exhaust gas; the dehumidification system comprises a hot dry air duct, an air distribution duct, a dry sludge silo and a hot and wet air duct, the air distribution duct is located at the bottom of the dry sludge silo, and a plurality of air jet holes are constructed on the air distribution duct; the hot dry air enters the air distribution duct located at the bottom of the dry sludge silo through the hot dry air duct, flows out through the air jet holes on the air distribution duct, passes through the gaps between the dry sludge in the dry sludge silo, and takes away the moisture in the dry sludge. At the same time, the hot dry air becomes hot and wet air, enters the hot and wet air duct, and is then treated by the exhaust gas treatment system. This technical means can remove an additional 5-20% of the moisture content of the dry sludge.

[0026] In addition to the above-described purposes, features and effects, the present invention has other purposes, features and effects. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic elevation diagram of the dust removal, heat exchange and air supply integrated machine of the present invention;

[0028] Figure 2 This is a schematic diagram of the air distribution of the dry sludge silo of the present invention;

[0029] Figure 3 It is a process principle block diagram of the present invention.

[0030] Explanation of the numbers in the schematic diagram: 1. Air inlet box, 11. Air inlet, 2. Dust removal and filter box, 3. Heat exchanger, 4. Air supply box, 41. Air outlet, 5. Hot and dry air duct, 6. Air distribution duct, 7. Dry sludge silo, 8. Hot and wet air duct. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings and embodiments.

[0032] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in this specification and are not used to limit the conditions for implementation of the present invention. Therefore, they have no substantial technical significance. Any modification of the structure, change in the proportion relationship, or adjustment of the size shall still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose of the present invention. At the same time, the terms such as "upper, lower," "inlet, outlet," "cold, hot," etc. cited in this specification are only for the convenience of description and are not used to limit the scope of implementation. Changes or adjustments in their relative relationships shall be considered as the scope of implementation of the present invention without substantially changing the technical content.

[0033] At present, the residual sludge generated by the municipal sewage treatment plant, after mechanical deep dewatering or heat drying, the dry sludge moisture content is usually between 30%-60%, then through the conveying screw or scraper machine to the dry sludge storage bin for storage, regularly discharged to the transport vehicle for final disposal. It is known that the so-called dry sludge refers to the sludge formed after dewatering or heat drying treatment. The residence time of the dry sludge storage bin is generally one to two days, which is quite long compared with the tens of minutes to two hours of the upstream treatment dewatering / drying equipment. The long residence time of the dry sludge in the storage bin can be fully utilized to further dehumidify, so as to reduce the moisture content of the sludge discharged from the upstream sludge dewatering or drying unit, and further reduce the operating cost or improve the yield.

[0034] Based on the above situation, the basic idea of the present application is to set a wind distribution pipe at the bottom of the dry sludge bin, so that the hot dry wind flows upward along the gap in the dry sludge, carrying away the moisture in the dry sludge, and completing the further dehumidification of the dry sludge.

[0035] Reference Figures 1 to 3 The dry sludge bin dehumidification device of the embodiment of the present application comprises a hot air system, a dehumidification system and a tail gas treatment system connected in sequence.

[0036] The hot air system is used to form hot dry wind.

[0037] The tail gas treatment system is used to treat tail gas.

[0038] The dehumidification system comprises a hot dry wind pipe 5, a wind distribution pipe 6, a dry sludge bin 7 and a hot and humid wind pipe 8. The wind distribution pipe 6 is located at the bottom of the dry sludge bin 7, and a plurality of air injection holes are formed on the wind distribution pipe 6.

[0039] The hot dry wind enters the wind distribution pipe 6 at the bottom of the dry sludge bin 7 through the hot dry wind pipe 5, flows out through the air injection holes on the wind distribution pipe 6, passes through the gap between the dry sludge in the dry sludge bin 7, carries away the moisture in the dry sludge, and at the same time, the hot dry wind becomes hot and humid wind, enters the hot and humid wind pipe 8, and then is treated by the tail gas treatment system.

[0040] The existing dry sludge bin only has the function of storage, and does not have the dehumidification function under the condition of long residence time, which causes the current dewatering and drying process to only control the moisture content of the outlet of the upstream treatment sludge / drying equipment, so that the process control difficulty increases and the operating cost rises. By combining the waste heat that can be utilized by the sewage treatment plant (such as the high room temperature in the air blower room or the heat provided by the sewage source heat pump, the waste heat of the low-temperature drying machine, etc.) and the long residence time of the dry sludge bin, the drug consumption and energy consumption of the upstream treatment sludge dewatering / drying equipment can be maximized under the premise of meeting the moisture content required by the sludge final treatment unit.

[0041] Aerial blower 4 draws ambient cold air into the dry sludge silo dehumidification device. A primary filter with a filtration accuracy of 5 μm can be installed at the initial end to remove most dust from the cold air, preventing dust accumulation in the subsequent heat exchanger, which affects its heat exchange efficiency. The filtered cold dry air is then piped to the heat exchanger. The heat exchanger's heat source can be a waste heat heat pump or hot air from the factory's blower room. The heat exchanger heats the cold dry air to form hot dry air, which is then pressurized by blower 4 and delivered to the air distribution duct 6 at the bottom of the dry sludge silo. Perforated pipes are installed on the lower side of the bottom air distribution duct to evenly distribute the hot dry air to the bottom of the silo. From the bottom of the silo, the hot dry air flows upward through the gaps between the dry sludge, further heating the dry sludge, enhancing convection on the sludge surface and accelerating the dehumidification of the dry sludge. As the hot dry air rises, its temperature drops and its humidity increases. By the time it reaches the top of the dry silo, it is essentially saturated, forming hot and humid air at a slightly lower temperature. As long as the air volume and temperature of the hot dry air entering the dry sludge silo are controlled, the required dehumidification function can be achieved, and the operation of the entire drying system will be more stable and reliable.

[0042] Preferably, the air jet holes are located on the lower side of the air distribution pipe 6. This location effectively prevents sludge in the dry sludge silo from clogging the air jet holes, ensuring that the air jet passage remains unobstructed. If the air jet holes were located on the upper side of the air distribution pipe 6, sludge in the dry sludge silo could clog the air jet holes, preventing smooth airflow and affecting the dehumidification effect.

[0043] Specifically, the plurality of air jet holes on the air distribution pipe 6 are evenly distributed on the air distribution pipe 6. This arrangement enables the hot dry air to evenly pass through the gaps between the dry sludge upwards, effectively preventing the dry sludge from having uneven dehumidification in some areas.

[0044] Furthermore, perforated tubes (not shown) can be installed over the several air jet holes on the air distribution pipe 6. The bottom of the perforated tubes communicates with the air jet holes, and the top of the perforated tubes is open. Hot dry air flows into the perforated tubes through the several air jet holes on the air distribution pipe 6, and flows out through the top opening of the perforated tubes, then passes through the gaps between the dry sludge. Providing perforated tubes on the air distribution pipe 6 further prevents dry sludge from clogging the air jet holes, allowing for smoother diffusion of the hot air.

[0045] Alternatively, a mesh grille may be provided at the top opening of the air jet hole or the perforated pipe to prevent sludge from clogging the air hole and to prevent the hot air from flowing out.

[0046] Of course, as needed, a filter (not shown) can be set on the top of the dry sludge silo 7, and the hot and wet air is filtered by the filter and enters the hot and wet air duct 8. The filter can effectively prevent the hot and wet air from carrying out fine particles of dry sludge, so as to facilitate further processing of the hot and wet air.

[0047] It should be noted that the air distribution pipe 6 needs to be located 300 mm to 500 mm above the arch-breaking slide of the dry sludge silo to avoid affecting the normal operation of the arch-breaking slide.

[0048] In terms of the connection method between the air distribution duct 6 and the hot dry air duct 5, it is preferred that one end of the air distribution duct 6 is connected to the hot dry air duct 5, and the other end of the air distribution duct 6 is closed; the hot dry air duct 5 can also be arranged in the middle position of the air distribution duct 6, in which case both ends of the air distribution duct 6 are closed.

[0049] In some embodiments, the hot air system includes an air inlet box 1, a dust removal filter box 2, a heat exchanger 3 and an air supply box 4 connected in sequence;

[0050] The cold air enters the air inlet 11 of the air inlet box 1, passes through the dust removal filter box 2 to filter the dust, enters the heat exchanger 3 to be heated to become hot dry air, and then enters the hot dry air duct 5 through the air outlet 41 after being pressurized by the air supply box 4.

[0051] Preferably, the cold dry air is heated using hot water from a waste heat heat pump or hot air from the plant's blower room via heat exchanger 3. Municipal sewage treatment plants are typically equipped with a blower room, which houses multiple blowers that supply oxygen to the biochemical treatment unit. Due to the high power of these blowers, the heat generated by their operation can cause the room to heat up. Currently, heat is often removed from the room through convection using axial fans, which essentially wastes this heat and does not meet the requirements of low-carbon and environmentally friendly policies. Therefore, utilizing this heat to heat the cold dry air can fully recycle and reuse resources.

[0052] The exhaust gas treatment system uses a factory deodorization system, which is conducive to recycling, reuse, energy conservation and environmental protection. The exhaust gas treatment system can be a biochemical treatment system, in which case the exhaust gas needs to be filtered and pressurized before being connected to the biochemical treatment system. Of course, a new exhaust gas treatment system can also be built.

[0053] The technical solution of the present invention requires only a small investment and a small increase in operating costs, and can further remove the moisture content of the dry sludge in the dry sludge silo by 5%-20%. In other words, the moisture content control value of the upstream sludge dehydration and drying system can be increased by 5%-20%, thereby reducing the operating drug consumption and energy consumption of the upstream sludge glue drying system by 10%-30%.

[0054] For example, a municipal sludge dewatering and drying project in Northeast China processes 41.6 DS of absolute dry sludge per day. The sludge is drawn from the municipal sewage treatment plant's thickening tanks and transferred to a sludge balancing tank. The sludge is then pumped via a screw pump to a deep dewatering and drying workshop. The primary process for this process is a two-stage high-pressure belt filter press combined with a low-temperature drying process.

[0055] In the sludge drying workshop, the moisture content of the sludge in the thickening tank is 95%. It is first dehydrated to 70%-72% by a high-pressure belt machine, and then enters the low-temperature drying system. The centrifugal heat pump heats the sludge in two low-temperature dryers to further reduce the moisture content to 40%, and then enters the outdoor 80m 3 Dry sludge is stored in silos and transported out for incineration regularly.

[0056] The excess heat from the centrifugal heat pumps used by the low-temperature dryers was transferred to the plant's reclaimed water via a plate heat exchanger, without being reused, resulting in wasteful heat. Therefore, this project utilized the excess heat from the centrifugal heat pumps by adding a dry sludge silo dehumidification system. This increased the moisture content of the sludge discharged from the two low-temperature dryers from 40% to 50%, thereby increasing production and reducing drying energy consumption. The remaining 10% moisture content was removed by this dehumidification system in the outdoor dry silo.

[0057] Process principle Figure 3 As shown, a water-to-air heat exchanger is added next to the existing plate heat exchanger and used in parallel. Outdoor air passes through dust removal and filtration before entering the water-to-air heat exchanger. It is heated by the heat transfer from the heat pump's cold water and then pressurized by the ventilator before entering the bottom of the dry sludge silo (above the broken arch). In extreme winter temperatures, hot air from a blower can be used to supplement the heat.

[0058] By calculating the three operating conditions of annual average operating conditions, winter operating conditions and summer operating conditions, the design uses an outdoor dry material silo to reduce the moisture content of the feed from 50% to 40%. The heat exchanger area requirements and air volume requirements under the three operating conditions are summarized in the following table.

[0059] Process summary data table for three working conditions

[0060]

[0061] The main equipment list is as follows:

[0062] Equipment list for further dehumidification system using outdoor dry material silo

[0063]

[0064]

[0065] Analysis of investment costs and investment returns

[0066] The investment in the silo dehumidification system is approximately 400,000 yuan. The addition of this system will increase the system's processing capacity, raising dry material production from 33 tons per day to 41.6 tons per day. Based on a revenue of 400 yuan per ton, this translates to an annual revenue increase of 1.2556 million yuan. The electricity cost of the additional 11 kW ventilation fan is offset by the electricity savings from the reclaimed water cooling pump (rated at 22 kW). The investment is expected to be recovered in approximately 3-4 months, representing significant economic benefits.

[0067] The above is a schematic description of the present invention and its embodiments, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. If a person skilled in the art is inspired by the above, and does not deviate from the purpose of the invention, without creatively designing a structure similar to the present technical solution, it shall fall within the scope of protection of the present invention.

Claims

1. A dry sludge silo dehumidification device, comprising a hot air system, a dehumidification system, and an exhaust gas treatment system connected in sequence; The hot air system is used to generate hot dry air; The tail gas treatment system is used to treat tail gas; It is characterized by: The dehumidification system comprises a hot dry air pipe (5), an air distribution pipe (6), a dry sludge silo (7) and a hot wet air pipe (8), wherein the air distribution pipe (6) is located at the bottom of the dry sludge silo (7), and a plurality of air jet holes are configured on the air distribution pipe (6); The hot dry air enters the air distribution pipe (6) located at the bottom of the dry sludge silo (7) through the hot dry air pipe (5), flows out through the air jet holes on the air distribution pipe (6), passes through the gaps between the dry sludge in the dry sludge silo (7), and takes away the moisture in the dry sludge. At the same time, the hot dry air is converted into hot wet air, enters the hot wet air pipe (8), and is then processed by the exhaust gas treatment system.

2. The dry sludge silo dehumidification device according to claim 1, characterized in that: The air injection hole is located on the lower side of the air distribution pipe (6).

3. The dry sludge silo dehumidification device according to claim 2, characterized in that: The plurality of air injection holes on the air distribution pipe (6) are evenly distributed on the air distribution pipe (6).

4. The dry sludge silo dehumidification device according to any one of claims 1 to 3, characterized in that: A perforated pipe is installed on the plurality of jet holes on the air distribution pipe (6), the bottom of the perforated pipe is communicated with the jet holes, and the top end of the perforated pipe is open. Hot dry air flows into the perforated pipe through the plurality of jet holes on the air distribution pipe (6), flows out from the top end opening of the perforated pipe, and then passes through the gaps between the dry sludge.

5. The dry sludge silo dehumidification device according to claim 4, characterized in that: A filter is provided on the top of the dry sludge silo (7), and the hot and wet air is filtered by the filter and then enters the hot and wet air duct (8).

6. The dry sludge silo dehumidification device according to claim 5, characterized in that: The air distribution pipe (6) is located 300 mm to 500 mm above the arch-breaking slide frame of the dry sludge silo.

7. The dry sludge silo dehumidification device according to claim 6, characterized in that: One end of the air distribution pipe (6) is connected to the hot dry air pipe (5), and the other end of the air distribution pipe (6) is closed.

8. The dry sludge silo dehumidification device according to claim 1, characterized in that: The hot air system comprises an air inlet box (1), a dust removal filter box (2), a heat exchanger (3) and an air supply box (4) which are connected in sequence; The cold air enters the air inlet (11) of the air inlet box (1), passes through the dust removal filter box (2) to filter the dust, enters the heat exchanger (3) to be heated to become hot dry air, and then enters the hot dry air duct (5) through the air outlet (41) after being pressurized by the air supply box (4).

9. The dry sludge silo dehumidification device according to claim 8, characterized in that: The hot water from the waste heat heat pump or the hot air from the blower room in the factory is used to heat the cold dry air through the heat exchanger (3).

10. The dry sludge silo dehumidification device according to claim 1, characterized in that: The tail gas treatment system is a factory deodorization system.

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