Sludge Heat Pump Drying Airflow Optimization System

Abstract

The present invention relates to the field of sludge drying, and discloses a sludge heat pump drying air flow optimization system. The system includes a condensate collection device, a air supply device, a heat pump system, a air circulation system and a sludge treatment device; the heat pump system is responsible for supplying hot air and condensing the water vapor in the wet air to the condensate collection device. The hot air is introduced into the drying room through the air supply device to dry the sludge on the conveyor belt. The formed wet air flows back to the heat pump system through the upper air outlet; the air flow velocity of the hot air flowing out of the air blower decays after flowing through the lower conveyor belt. Therefore, the drying air flow velocity of the upper layer of sludge on the conveyor belt is lower than that of the lower layer, while the moisture content of the upper layer of sludge is higher than that of the lower layer. The moisture content and the air flow velocity do not match, resulting in a low drying efficiency. The present invention provides a flow guiding partition component between the upper and lower conveyor belts, which increases the drying air flow velocity of the upper layer and enhances the mass transfer effect of the upper layer of sludge with high moisture content. Thus, by optimizing the drying air flow system, the sludge drying efficiency is significantly improved.

Description

Technical Field

[0001] The present invention relates to a sludge treatment system, and particularly to a sludge drying system. Background Art

[0002] At present, with the development of China's economic society, the output of domestic industrial wastewater and domestic sewage is continuously increasing, and sludge, a by-product, will be generated during the treatment of the above-mentioned sewage. The total output of sludge in China in 2018 was 56.65 million tons, and GEP Research expects that the total output of sludge in China will reach 61.77 million tons by 2020, with an expected compound annual growth rate of about 4% in the next three years. Sludge has a complex composition, containing nutrients such as nitrogen, phosphorus, and potassium, organic matter that can be utilized, toxic and harmful and difficult-to-degrade organic matter, heavy metals, and pathogenic bacteria. Moreover, sludge has a high water content and is prone to corruption and odor. In order to achieve the goal of harmlessness and resource utilization of sludge, sludge drying treatment is required.

[0003] Heat pump drying technology has the characteristics of high energy efficiency, and the heat pump system has high reliability and is widely used in the field of sludge drying. However, there is a problem of low efficiency in the internal air supply of the drying chamber. During the sludge drying process in the conveyor belt drying mode, the moisture content of the sludge gradually decreases, but the actual air supply does not consider the difference in the moisture content of the sludge on the upper and lower layers of the conveyor belt. Simply increasing the heat pump power cannot effectively improve the drying efficiency. Therefore, it is necessary to design a heat pump drying air flow system based on the concept of cascade air supply. Summary of the Invention

[0004] The purpose of the present invention is to provide an optimized heat pump drying air flow system for sludge, which conforms to the principle of cascade air supply, realizes the matching of sludge moisture content and wind speed, enhances the heat and mass transfer effect, and reduces the energy consumption of sludge drying.

[0005] The purpose of the present invention is achieved as follows: An optimized heat pump drying air flow system for sludge includes a condensate collection device, a air supply device, a heat pump system, a air circulation system, and a sludge treatment device;

[0006] The condensate collection device includes a condensate pipe (15) and a water tank (16) arranged outside the heat pump system (1). The condensate collection device is used to collect the condensate generated after heat exchange in the heat pump system;

[0007] The air supply device includes a air blower (3) and a motor (4) arranged at the bottom of the drying chamber (17). The air supply device is used to blow the hot air generated by the heat pump system (1) into the drying chamber;

[0008] The heat pump system (1) is used to generate hot air, and at the same time, it can also receive the wet air generated by the drying chamber (17), condense it, and realize the air circulation in the drying chamber (17);

[0009] The air circulation system includes an air inlet duct (2), a wind baffle on the sludge outlet side (5), a flow guiding partition assembly (9), a left wind baffle (14), an air outlet (12), and an air outlet duct (13). The air circulation system is used to realize the air circulation between the drying chamber (17) and the heat pump system (1). The air inlet duct (2) connects the air outlet of the heat pump system (1) and the air blower (3). The wind baffle on the sludge outlet side (5) and the left wind baffle (14) are used to guide the hot air in the drying chamber (17). The flow guiding partition assembly (9) is used to control the air flow rate between the sludge treatment devices. The air outlet (12) and the air outlet duct (13) are used to connect the drying chamber (17) and the air inlet of the heat pump system (1);

[0010] The sludge treatment device includes a sludge inlet (10), a conveyor chain belt (8), side baffles of the chain belt (7), and a baffle at the sludge outlet (6). The sludge treatment device is used to convey sludge so that the sludge is in full contact with hot air to achieve drying. The conveyor chain belt (8) is arranged in the middle of the drying chamber (17).

[0011] As a further limitation of the present invention: The conveyor chain belt (8) is provided with two layers.

[0012] As a further limitation of the present invention: The left wind baffle (14) is arranged beside the discharge end of the upper conveyor chain belt (8). While playing the role of guiding hot air, the left wind baffle (14) also plays the role of guiding when the sludge is transferred from the upper conveyor chain belt (8) to the lower conveyor chain belt (8). The wind baffle on the sludge outlet side (5) is arranged below the discharge end of the lower conveyor chain belt (8) and beside the baffle at the sludge outlet (6). While playing the role of guiding hot air, the wind baffle on the sludge outlet side (5) also plays the role of guiding the discharge of sludge.

[0013] As a further limitation of the present invention: The flow guiding partition assembly (9) is arranged between the two layers of conveyor chain belts (8).

[0014] As a further limitation of the present invention: The flow guiding partition assembly (9) includes multiple pairs of inclined partitions in a symmetric "eight" shape, and adjacent pairs of inclined partitions are connected by a horizontal partition.

[0015] As a further limitation of the present invention: The bottom of the inclined partition is hinged on the side wall of the drying chamber (17), and the angle between the inclined partition and the horizontal plane is 45° - 60°.

[0016] As a further limitation of the present invention: The length of the inclined partition is twice the length of the horizontal partition.

[0017] As a further limitation of the present invention: The air outlet of the air blower (3) faces directly upward.

[0018] As a further limitation of the present invention: the sludge outlet baffle (6) is a spring baffle.

[0019] As a further limitation of the present invention: the side baffle (7) of the chain belt cooperates with the conveyor chain belt (8).

[0020] The present invention adopts the above technical solutions and has the following advantages:

[0021] 1. The air circulation system of the present invention is enclosed, and the sludge outlet baffle is designed as a spring type, effectively avoiding the leakage of the air flow in the drying room, so as to prevent the harmful gases inside the drying room from polluting the environment.

[0022] 2. The present invention arranges side baffles of the chain belt on both sides in the transverse direction of the conveyor chain belt, avoiding the sludge from falling to the ground of the drying room, causing equipment damage or increasing the air flow resistance at the bottom.

[0023] 3. In view of the difference in the moisture content of the sludge on the upper and lower layers of the conveyor chain belt, according to the concept of stepped air supply, the present invention designs a diversion baffle assembly to increase the air flow speed of the upper layer of the sludge during drying, enhance the mass transfer effect of the upper layer of the sludge with high moisture content, and significantly improve the sludge drying efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the sludge heat pump drying air flow optimization system of the present invention.

[0025] Figure 2 It is a schematic diagram of different inclination angles, lengths of inclined baffles and lengths of transverse baffles of the spacer assembly of the conveyor chain belt of the present invention.

[0026] Figure 3 It is a cloud diagram of the drying air flow velocity field inside the drying room of the present invention.

[0027] Description of the reference numerals: 1 heat pump system, 2 air inlet pipe, 3 air blower, 4 motor, 5 wind baffle on the sludge outlet side, 6 sludge outlet baffle, 7 side baffle of the chain belt, 8 conveyor chain belt, 9 diversion baffle assembly, 10 sludge inlet, 11 drying room support, 12 air outlet, 13 air outlet pipe, 14 left wind baffle, 15 condensate pipe, 16 water tank, 17 drying room. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be further described in detail below with reference to the accompanying drawings.

[0029] As Figure 1-2 shown, a sludge heat pump drying air flow optimization system includes a condensate water collection device, a air supply device, a heat pump system, an air circulation system and a sludge treatment device;

[0030] The condensate water collection device includes a condensate pipe 15 and a water tank 16 arranged outside the heat pump system 1, and the condensate water collection device is used to collect the condensate water generated after heat exchange in the heat pump system 1;

[0031] The air supply device includes a blower 3 and a motor 4 arranged at the bottom of the drying chamber 17. The air supply device is used to blow the hot air generated by the heat pump system 1 into the drying chamber, and the air outlet of the blower 3 faces directly upward.

[0032] The heat pump system 1 is used to generate hot air, and at the same time, it can also receive the wet air generated by the drying chamber 17, condense it, and realize the air circulation in the drying chamber 17.

[0033] The air circulation system includes an air inlet pipe 2, a sludge outlet side wind baffle 5, a flow guiding partition assembly 9, a left side wind baffle 14, an air outlet 12, and an air outlet pipe 13. The air circulation system is used to realize the air circulation between the drying chamber 17 and the heat pump system 1. The air inlet pipe 2 connects the air outlet of the heat pump system 1 and the blower 3. The sludge outlet side wind baffle 5 and the left side wind baffle 14 are used to guide the hot air in the drying chamber 17. The flow guiding partition assembly 9 is used to control the air flow rate between the sludge treatment devices. The air outlet 12 and the air outlet pipe 13 are used to connect the drying chamber 17 and the air inlet of the heat pump system 1.

[0034] The sludge treatment device includes a sludge inlet 10, a conveyor chain belt 8, chain belt side baffles 7, and a sludge outlet baffle 6. The sludge treatment device is used to convey sludge, so that the sludge is in full contact with the hot air to realize drying. The conveyor chain belt 8 is arranged in the middle of the drying chamber 17. The sludge outlet baffle 6 is a spring baffle. The chain belt side baffles 7 cooperate with the conveyor chain belt 8. The conveyor chain belt 8 has two layers. The left side wind baffle 14 is arranged beside the discharge end of the upper layer conveyor chain belt 8. The left side wind baffle 14 not only plays a role in guiding the hot air, but also plays a role in guiding the sludge when it is transferred from the upper layer conveyor chain belt 8 to the lower layer conveyor chain belt 8. The sludge outlet side wind baffle 5 is arranged below the discharge end of the lower layer conveyor chain belt 8 and beside the sludge outlet baffle 6. The sludge outlet side wind baffle 5 not only plays a role in guiding the hot air, but also plays a role in guiding the discharge of sludge. The flow guiding partition assembly 9 is arranged between the two layers of conveyor chain belts 8. The flow guiding partition assembly 9 includes multiple pairs of inclined partitions in a symmetric "eight" shape. Adjacent pairs of inclined partitions are connected by a horizontal partition. The bottom of the inclined partition is hinged on the drying chamber support 11, and the angle between the inclined partition and the horizontal plane is 45° - 60°.

[0035] See Figure 1 , in the heat pump system 1, the hot air at the outlet of the condenser is conveyed directly upward to the drying chamber 17 by the blower 3 driven by the motor 4. Constrained by the left side wind baffle 14 and the sludge outlet side wind baffle 5, the hot air is concentrated and blown from the bottom to the sludge on the conveyor chain belt 8, so that the moisture in the sludge is precipitated through the internal pores of the sludge and is carried away by the hot air, and flows to the heat pump system 1 through the air outlet pipe 13. In the heat pump system 1, the evaporator condenses and dehumidifies the wet air, and the condensed water is collected in the water tank 16 through the condensate pipe 15.

[0036] For the sludge treatment equipment, sludge is introduced from the sludge inlet 10, conveyed by the conveyor chain belt 8, the internal moisture diffuses and evaporates into the hot air, and the moisture content gradually decreases along the sludge conveying direction, and finally is conveyed to the outlet baffle 6 to realize the recovery of dried sludge.

[0037] Considering that the time required for sludge drying is relatively long, the conveyor chain belt 8 is divided into upper and lower layers, so that the sludge is gradually dried and meets the recovery requirements. At the same time, considering the flexibility of the sludge itself, it is easy to fall to the ground and damage the equipment arranged on the ground. Therefore, a chain belt side baffle 7 is provided for the conveyor chain belt 8 to effectively prevent the sludge from overflowing from the side of the conveyor chain belt 8.

[0038] In the wind circulation system, a flow guiding baffle component 9 is arranged between the upper and lower conveyor chain belts 8, as Figure 2 shown. The baffles in the flow guiding baffle component 9 are in a symmetric "eight" shape. The length of the inclined baffle is 2L and the length of the horizontal baffle is L. The setting of the flow guiding baffle component 9 can increase the drying air flow velocity of the upper layer, thereby increasing the mass transfer amount of the high moisture content sludge in the upper layer, that is, the water analysis amount, and then significantly improving the sludge drying efficiency.

[0039] Considering the change of the drying working condition caused by the different moisture contents of the supplied sludge, the inclination angle of the baffle is designed to be adjustable from 45° to 60°. When the moisture content of the supplied sludge is relatively low, the inclination angle of the baffle is correspondingly increased to reduce the air flow resistance. When the moisture content of the supplied sludge is relatively high, the inclination angle of the baffle is correspondingly reduced to further increase the air flow velocity of the drying air flow of the upper layer sludge and enhance the mass transfer effect of the high moisture content sludge in the upper layer. As Figure 3 shown in the cloud map of the drying air flow velocity field inside the drying room 17, the air flow velocity at the outlet of the upper end included angle of the flow guiding baffle is as high as 5.5 m / s, which can effectively improve the convective heat and mass transfer effect between the upper layer sludge and the wet air.

[0040] In summary, the wind circulation system of the present invention is closed, and the outlet baffle 6 is designed as a spring type to effectively prevent the air flow in the drying room 17 from leaking out, so as to avoid the pollution of the environment by the harmful gases inside the drying room 17; a chain belt side baffle 7 is provided for the conveyor chain belt 8 to effectively prevent the sludge from overflowing from the side of the conveyor chain belt 8 and causing equipment damage; aiming at the difference in the moisture content of the sludge in the upper and lower layers of the conveyor chain belt 8, according to the concept of cascade air supply, a flow guiding baffle component 9 is designed to increase the air flow velocity of the drying air flow of the upper layer sludge and enhance the mass transfer effect of the high moisture content sludge in the upper layer, and significantly improve the sludge drying efficiency.

[0041] The present invention is not limited to the above embodiments. Based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and deformations of some technical features without creative labor according to the disclosed technical content, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A sludge heat pump drying air flow optimization system, characterized in that, It includes a condensate collection device, a air supply device, a heat pump system (1), a air circulation system and a sludge treatment device; the condensate collection device includes a condensate water pipe (15) and a water tank (16) arranged outside the heat pump system (1), and the condensate collection device is used to collect the condensate water generated after heat exchange in the heat pump system (1); the air supply device includes a air blower (3) and a motor (4) arranged at the bottom of the drying chamber (17), and the air supply device is used to blow the hot air generated by the heat pump system (1) into the drying chamber; the heat pump system (1) is used to generate hot air, and at the same time, it can also receive the wet air generated by the drying chamber (17), condense it, and realize the air circulation in the drying chamber (17); the air circulation system includes an air inlet pipe (2), a sludge outlet side wind baffle (5), a flow guiding partition component (9), a left side wind baffle (14), an air outlet (12), and an air outlet pipe (13), and the air circulation system is used to realize the air circulation between the drying chamber (17) and the heat pump system (1). The air inlet pipe (2) connects the air outlet of the heat pump system (1) and the air blower (3). The sludge outlet side wind baffle (5) and the left side wind baffle (14) are used to guide the hot air in the drying chamber (17). The flow guiding partition component (9) is used to control the air flow rate between the sludge treatment devices. The air outlet (12) and the air outlet pipe (13) are used to connect the drying chamber (17) and the air inlet of the heat pump system (1); the sludge treatment device includes a sludge inlet (10), a conveyor chain belt (8), a chain belt side baffle (7), and a sludge outlet baffle (6). The sludge treatment device is used to convey sludge so that the sludge is in full contact with the hot air to achieve drying. The conveyor chain belt (8) is arranged in the middle of the drying chamber (17). The left side wind baffle (14) is arranged beside the discharge end of the upper conveyor chain belt (8). While playing the role of guiding the hot air, the left side wind baffle (14) also plays the role of guiding the sludge when the sludge is transferred from the upper conveyor chain belt (8) to the lower conveyor chain belt (8). The sludge outlet side wind baffle (5) is arranged below the discharge end of the lower conveyor chain belt (8) and beside the sludge outlet baffle (6). While playing the role of guiding the hot air, the sludge outlet side wind baffle (5) also plays the role of guiding the discharge of the sludge. The flow guiding partition component (9) is arranged between the two layers of conveyor chain belts (8). The flow guiding partition component (9) includes multiple pairs of inclined partitions in a symmetric "eight" shape, and adjacent pairs of inclined partitions are connected by a horizontal partition. The bottom of the inclined partition is hinged on the side wall of the drying chamber (17), and the included angle between the inclined partition and the horizontal plane is 45° - 60°. The length of the inclined partition is twice the length of the horizontal partition. The air outlet (12) of the air blower (3) faces directly upward. The sludge outlet baffle (6) is a kind of spring baffle. The chain belt side baffle (7) cooperates with the conveyor chain belt (8).

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