Waste heat recycling system for sludge drying

Abstract

The utility model discloses a waste heat recycling system for sludge drying, which belongs to the technical field of sludge treatment and comprises a mesh belt conveyor which is horizontally arranged on a support frame and keeps rotating conveying; the air inlet pipes are arranged on the two opposite sides of the supporting frame, and an air outlet is kept to be located in the middle of the mesh belt conveyor. The shell is arranged on the supporting frame; one end of the hot air circulating device is communicated with the interior of the shell, and the other end of the hot air circulating device is communicated with the air inlet pipe. The system can conveniently collect uncooled hot air in the sludge drying process and dry the sludge again, and is convenient to recycle, so that the energy loss is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of sludge treatment, and particularly relates to a waste heat recycling system for sludge drying. Background Art

[0002] With the continuous development of the economy and the accelerating pace of urban environmental construction in China, the sewage treatment volume and scale are getting larger and larger, and the amount of sludge generated is also increasing. The traditional sludge treatment and disposal methods can no longer meet the requirements of sewage treatment. At present, there are two technical routes for sludge treatment: one is composting, and the main problems are serious environmental pollution, large investment, large system occupation area, and some sludge contains heavy metal pollution and cannot be used for agriculture; the other is landfill treatment. According to the requirements of the national sludge landfill technical specification, wet sludge with 80% water content must be modified to meet the landfill strength of the landfill before it can enter the landfill. At present, some modification technologies have emerged in China, but the cost is not small. Coupled with the cost of the landfill, the landfill treatment cost is not economical. At the same time, landfill does not fundamentally solve the problem of sludge disposal, and it occupies a large amount of land resources. For a country with increasingly tense land, it should not be advocated.

[0003] In view of the above sludge treatment methods, some environmental protection factories prefer to use the sludge composting method for subsequent treatment of sludge. Sludge composting is a good soil conditioner. When compost is used in farmland, it can increase organic matter, improve soil structure, reduce the use of fertilizers, and can reduce the potential erosion of the soil. In the process of sludge composting, the first thing is to dry the sludge to reduce the water content of the sludge.

[0004] According to the drying form, sludge drying is divided into direct drying and indirect drying. Direct drying is to directly contact the hot drying medium (such as flue gas) with the sludge, transfer heat in a convection manner, and take away the evaporated water; indirect drying is to transfer heat from the heat medium such as steam to the sludge through the metal wall by conduction, and the evaporated water is taken away by the carrier gas such as air. However, the heat demand for drying sludge is large. During drying, part of the hot air realizes drying after contacting the sludge, but another part of the hot air may be directly discharged. Moreover, there is still a certain amount of waste heat after the hot air contacts the sludge and passes through the sludge. If it is directly discharged into the atmosphere, it will inevitably lead to serious energy consumption and high operating costs. Content of the Utility Model

[0005] Therefore, to address the above deficiencies, the present utility model provides a waste heat recycling system for sludge drying herein. This system conveys sludge through a mesh belt conveyor, and by combining with the air inlet pipes arranged on the sides, it facilitates the automated sludge drying. Meanwhile, through the housing above the mesh belt conveyor and the hot air circulation device, it is convenient to recycle the air that has passed through the sludge and has not cooled, facilitating the subsequent further drying of the sludge, thereby reducing energy consumption and operating costs.

[0006] The present utility model is implemented as follows: A waste heat recycling system for sludge drying is constructed, including a mesh belt conveyor horizontally placed on a support frame and kept rotating for conveying.

[0007] Air inlet pipes are arranged on the opposite sides of the support frame and the air outlet is kept at the middle position of the mesh belt conveyor.

[0008] A housing is arranged on the support frame.

[0009] A hot air circulation device is arranged on the housing and one end is kept communicating with the inside of the housing, and the other end is kept communicating with the air inlet pipe.

[0010] Specifically, a transmission box is arranged on the outer side of the support frame, a driving motor and a belt transmission mechanism are arranged inside the transmission box, and the belt transmission mechanism is kept in transmission connection with the mesh belt conveyor.

[0011] Specifically, the mesh belt of the mesh belt conveyor is in a closed loop, the air outlet of the air inlet pipe is arranged at the middle position of the loop, the air inlet of the air inlet pipe is kept connected with an external waste heat pipe, and an electric heater for heating the internal air is also arranged on the air inlet pipe.

[0012] Specifically, the hot air circulation device includes a hot air discharge pipe and a hot air circulation pipe. One end of the hot air discharge pipe is communicated with the middle position at the top of the housing, and the other end is kept closed. One end of the hot air circulation pipe is communicated with the hot air discharge pipe, and the other end is communicated with the air inlet pipe.

[0013] Specifically, a waste liquid discharge plate is also arranged below the mesh belt conveyor, and a waste discharge pipe is arranged at the bottom of the waste liquid discharge plate.

[0014] The present utility model has the following beneficial effects:

[0015] 1. This system can facilitate the automated conveying and drying of sludge through the mesh belt conveyor and the air inlet pipes on both sides of the mesh belt conveyor. Meanwhile, through the housing above the mesh belt conveyor and the hot air circulation device of the housing, it is convenient to centrally collect the air that has passed through the sludge and has not cooled and then return it to the air inlet pipe for conveying, thereby avoiding heat loss and saving energy costs.

[0016] 2. The system is equipped with a waste liquid discharge plate and a waste discharge pipe at the lower end of the mesh belt conveyor, which facilitates the discharge of water during sludge drying and also facilitates the discharge of cold air. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings are used to provide a further understanding of the present invention and form a part of the specification. They are used together with the specific embodiments of the present invention to explain the present invention, but do not constitute any limitation to the present invention. In the drawings:

[0018] Figure 1 is a schematic structural view of the present invention;

[0019] Figure 2 is Figure 1 a schematic view of the front view direction of

[0020] Figure 3 is Figure 2 a schematic view of the A-A cross-section in

[0021] Figure 4 is Figure 3 a gas flow diagram during sludge drying in (where the arrows indicate the hot air flow direction and the circles indicate the cold air flow direction);

[0022] In the figures: 1. Support frame; 2. Mesh belt conveyor; 3. Housing; 4. Hot air discharge pipe; 5. Hot air circulation pipe; 6. Air inlet pipe; 7. Electric heater; 8. Waste liquid discharge plate; 9. Transmission box; 10. Waste discharge pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The technical solutions of the present invention will be further specifically described below through specific embodiments in combination with the drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and do not constitute any limitation to the present invention. The drawings in the present invention are only used in conjunction with the embodiments for description and are convenient for understanding and use, and do not constitute any relevant limitation to the present invention.

[0024] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the limiting conditions that the present invention can be implemented. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention.

[0025] As described in the background art, a large amount of heat is required during the sludge drying process. During drying, a part of the hot air contacts the sludge and realizes drying, but another part of the hot air may be directly discharged. Moreover, there is still a certain amount of waste heat after the hot air passes through the sludge after contacting it. If it is directly discharged into the atmosphere, it will inevitably lead to serious energy consumption and high operating costs.

[0026] For the above reasons, please refer to the attached Figure 1 - attached Figure 3 , the present utility model provides a waste heat recycling system for sludge drying, including a mesh belt conveyor 2, which is horizontally placed on a support frame 1 and rotates for conveying;

[0027] An air inlet pipe 6 is arranged on the opposite sides of the support frame 1 and the air outlet is located at the middle position of the mesh belt conveyor 2;

[0028] A housing 3 is arranged on the support frame 1;

[0029] A hot air circulation device is arranged on the housing 3 and one end is in communication with the inside of the housing 3, and the other end is in communication with the air inlet pipe 6.

[0030] Specifically, a transmission box 9 is arranged on the outer side of the support frame 1. A driving motor and a belt transmission mechanism are arranged in the transmission box 9, and the belt transmission mechanism is in transmission connection with the mesh belt conveyor 2.

[0031] According to the above paragraph, both the driving motor and the belt transmission mechanism are common power components and transmission mechanisms in the mechanical field, and the connection method with the mesh belt conveyor is also a conventional connection method. Therefore, they are not shown in detail in the drawings.

[0032] Specifically, the mesh belt of the mesh belt conveyor 2 is in a closed ring shape. The air outlet of the air inlet pipe 6 is arranged at the middle position of the ring. The air inlet of the air inlet pipe 6 is connected to an external waste heat pipe. An electric heater 7 for heating the internal air is also arranged on the air inlet pipe 6.

[0033] According to the above paragraph, the mesh belt conveyor has the same structure as a conventional belt conveyor, except that the belt is replaced with a mesh belt (for the convenience of showing the drawings, the mesh holes on the mesh belt are not shown). The air outlet of the air inlet pipe is arranged between the upper and lower surfaces of the mesh belt. At the same time, the electric heater is a pipeline type air electric heater for facilitating the heating of the medium inside the pipeline.

[0034] Specifically, the hot air circulation device includes a hot air discharge pipe 4 and a hot air circulation pipe 5. One end of the hot air discharge pipe 4 is connected to the middle position at the top of the housing 3, and the other end is closed. One end of the hot air circulation pipe 5 is connected to the hot air discharge pipe 4, and the other end is connected to the air inlet pipe 6.

[0035] Specifically, a waste liquid discharge plate 8 is further arranged below the mesh belt conveyor 2, and a waste discharge pipe 10 is arranged at the bottom of the waste liquid discharge plate 8.

[0036] According to the above, the waste liquid discharge plate is provided to prevent the moisture mixed inside from flowing out randomly during the transportation and drying of the sludge. The waste discharge pipe is not only convenient for discharging the waste liquid, but also for discharging the cold air during the sludge drying process.

[0037] Please refer to the appendix Figure 3 and the appendix Figure 4 , when the sludge is dried, first, the sludge is evenly spread on the mesh belt conveyor 2 for transportation. At the same time, external air (such as the hot air discharged during the production of some processing equipment) is sucked into the waste heat pipe by an external air pump and then flows into the air inlet pipe 6. The air is heated under the heating effect of the electric heater 7 and then discharged into the mesh belt conveyor 2. Since air inlet pipes 6 are arranged on both sides of the mesh belt conveyor 2, the hot air discharged from the two air inlet pipes 6 will collide with each other and finally flow upward to contact the sludge on the mesh belt conveyor 2, realizing the drying of the sludge. After the hot air passes through the sludge, a part of the air is cooled due to heat exchange. The cooled hot air flows downward, passes through the mesh belt conveyor 2 and is discharged from the waste discharge pipe 10, while the uncooled hot air continues to flow upward, finally enters the hot air discharge pipe 4 and is discharged into the air inlet pipe 6 through the hot air circulation pipes 5 on both sides, realizing the circulating air supply and avoiding heat loss to the greatest extent.

[0038] The above description is a detailed description of the preferred and feasible embodiment of the present invention, but the embodiment is not used to limit the patent application scope of the present invention. Any equivalent changes or modifications completed under the technical spirit disclosed by the present invention shall fall within the patent scope covered by the present invention.

Claims

1. A waste heat recycling system for sludge drying, characterized in that: including a mesh belt conveyor, horizontally placed on a support frame and kept rotating for conveying; an air inlet pipe, arranged on opposite sides of the support frame and keeping the air outlet at the middle position of the mesh belt conveyor; a housing, arranged on the support frame; a hot air circulation device, arranged on the housing and keeping one end communicating with the inside of the housing and the other end communicating with the air inlet pipe.

2. The waste heat recycling system for sludge drying according to claim 1, wherein: A transmission box is arranged on the outer side surface of the support frame. A driving motor and a belt transmission mechanism are arranged in the transmission box, and the belt transmission mechanism is in transmission connection with the mesh belt conveyor.

3. The waste heat recycling system for sludge drying according to claim 1, wherein: The mesh belt of the mesh belt conveyor is in a closed ring shape. The air outlet of the air inlet pipe is arranged at the middle position of the ring. The air inlet of the air inlet pipe is connected with an external waste heat pipe. An electric heater for heating the internal air is also arranged on the air inlet pipe.

4. A waste heat recycling system for sludge drying according to claim 1, characterized in that: The hot air circulation device includes a hot air discharge pipe and a hot air circulation pipe. One end of the hot air discharge pipe is communicated with the middle position at the top of the housing, and the other end is kept closed. One end of the hot air circulation pipe is communicated with the hot air discharge pipe, and the other end is communicated with the air inlet pipe.

5. The waste heat recycling system for sludge drying according to claim 3, wherein: A waste liquid discharge plate is also arranged below the mesh belt conveyor. A waste discharge pipe is arranged at the bottom of the waste liquid discharge plate.

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