Solar fluidized bed dryer

Abstract

The utility model belongs to drying equipment technical field especially relates to a solar fluidized bed dryer. Contain solar energy collector and fluidized bed, and the air outlet end of solar energy collector is connected to the air inlet of fluidized bed through pipeline, is used for providing the air after heating for fluidized bed, still contain the environmental cold air bypass channel and auxiliary heating channel that communicate to the air inlet of fluidized bed, environmental cold air bypass channel is used for providing environmental cold air for fluidized bed, is equipped with auxiliary heating device on auxiliary heating channel, is used for providing the air after heating for fluidized bed, and the pipeline of solar energy collector, environmental cold air bypass channel and auxiliary heating channel all are equipped with valve body, and temperature sensor is equipped in fluidized bed or air inlet, is used for feedback regulation valve body's opening degree. Environmental cold air channel, auxiliary heating channel is supplemented with temperature sensor monitoring, can adaptability selection introduction environmental cold air or auxiliary heating, guarantees the gas temperature that input fluidized bed keeps certain range, guarantees the quality of grain drying.

Description

Technical Field

[0001] This utility model belongs to the field of drying equipment technology, and in particular relates to a solar fluidized bed dryer. Background Technology

[0002] After harvesting, grains generally need to be dried before storage to prevent pests or mold. Existing common methods for drying grains fall into two main categories: natural sun-drying and mechanized drying. Mechanized drying methods include microwave drying, vacuum drying, hot air drying, and infrared radiation drying. Grain drying is a crucial step in grain production, and reducing energy consumption, minimizing losses, and improving grain drying quality and production efficiency are the main goals of drying equipment research.

[0003] Currently, solar energy is widely used as an environmentally friendly new energy source. The applicant proposed a technical solution using a combination of solar collectors and fluidized beds to dry grains, utilizing solar radiation energy. During the implementation of this technology, the following problems were discovered: When used for heat-sensitive crops, due to the fluctuating nature of solar energy, the output temperature of the solar collector is related to the absorbed solar energy. Since heat-sensitive crops are highly sensitive to temperature, improper temperature during drying can easily lead to spoilage, affecting quality and economic value. Specifically, heat-sensitive crops are rich in heat-sensitive active ingredients, pigments, and volatile substances, requiring extremely high temperature and drying uniformity during the drying process. Excessive temperature or uneven heating can easily lead to the decomposition of their effective components, color deterioration, and poor taste, thus severely impacting their economic value. Therefore, in the technological development of solar energy for grain drying, there is a lack of precise, dynamic temperature regulation mechanisms to address the fluctuations in solar energy. Utility Model Content

[0004] To overcome the problem of lack of dynamic temperature regulation to account for fluctuations in solar energy when used for grain drying, this invention provides a solar fluidized bed dryer.

[0005] The technical solution adopted by this utility model to solve its technical problem is: A solar-powered fluidized bed dryer comprises a solar collector and a fluidized bed. The fluidized bed has a feed inlet, a discharge outlet, an air inlet, and an air outlet. The solar collector has an air inlet and an air outlet. The air outlet of the solar collector is connected to the air inlet of the fluidized bed via a pipeline to supply heated air to the fluidized bed. It also includes an ambient cold air bypass channel and an auxiliary heating channel connected to the air inlet of the fluidized bed. The ambient cold air bypass channel supplies ambient cold air to the fluidized bed, and the auxiliary heating channel is equipped with an auxiliary heating device to supply heated air to the fluidized bed. Valves are installed on the pipeline containing the solar collector, the ambient cold air bypass channel, and the auxiliary heating channel. Temperature sensors are installed inside the fluidized bed or at the air inlet to provide feedback and adjust the valve opening.

[0006] In this application, by adding an ambient cold air bypass channel and an auxiliary heating channel, and supplementing them with temperature sensor monitoring, ambient cold air or auxiliary heating can be introduced adaptively when solar energy fluctuates, thereby ensuring that the gas temperature input into the fluidized bed remains within a certain range to guarantee the quality of grain drying.

[0007] In some embodiments, a PLC control center is also included, which is connected to a temperature sensor signal. The PLC control center controls the opening degree of at least one valve in the pipeline where the solar collector is located, the ambient cold air bypass channel, and the auxiliary heating channel.

[0008] In some embodiments, a solar irradiance sensor is also included, which is connected to the PLC control center via a signal connection.

[0009] In some embodiments, the valve body on the pipeline where the solar collector is located and the ambient cold air bypass channel is a common three-way regulating valve.

[0010] In some embodiments, the fluidized bed is a vibrating fluidized bed.

[0011] In some embodiments, the pipeline containing the solar collector and the auxiliary heating channel share a single induced draft fan as the power drive device.

[0012] In some embodiments, the solar collector is a flat-plate solar collector, comprising a top glass cover, an inner heat-absorbing plate, and a bottom insulation layer.

[0013] In some embodiments, the absorber plate is configured as a baffle structure to increase the residence time of air in the solar collector.

[0014] In some embodiments, the fluidized bed is provided with an observation window to facilitate external observation of the interior.

[0015] In some embodiments, the outlet of the fluidized bed is connected to a discharge pipe, which shares a portion of the pipe wall with the inlet pipe leading to the solar collector or auxiliary heating device, and the shared pipe wall area uses a heat exchange plate.

[0016] The beneficial effects of this utility model are: By adding an ambient cold air bypass channel and an auxiliary heating channel, and supplementing them with temperature sensor monitoring, ambient cold air or auxiliary heating can be introduced adaptively when solar energy fluctuates, thereby ensuring that the gas temperature input into the fluidized bed remains within a certain range to guarantee the quality of grain drying. Attached Figure Description

[0017] Figure 1 A schematic diagram of the structure of the solar fluidized bed dryer provided by this utility model; Figure 2 for Figure 1 Schematic diagram of a medium-plate solar collector; Figure 3 for Figure 2 A schematic diagram of the internal heat absorption plate of a medium-plate solar collector; Figure 4 for Figure 2 Schematic diagram of the inlet and outlet positions on both sides of a medium-plate solar collector; Figure 5 for Figure 1 A schematic diagram of the structure of the vibrating fluidized bed section.

[0018] Explanation of reference numerals in the attached figures: 1. Integrated support frame, 2. Exhaust fan, 3. Flat plate solar collector, 3-1. Glass cover plate, 3-2. Heat absorber plate, 3-3. Hot air inlet, 3-4. Air inlet, 3-5. Air outlet, 3-6. Insulation layer, 4. Three-way regulating valve, 5. Ambient cold air bypass channel, 6. Discharge pipe, 6-1. Heat exchange plate, 7. Feed inlet, 8. Air outlet, 9. Discharge outlet, 10. Vibrating motor, 11. Auxiliary heating device, 12. PLC control center, 13. Conveyor belt. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings.

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0021] like Figures 1-5 As shown, this utility model provides a solar fluidized bed dryer.

[0022] like Figure 1 As shown, the solar fluidized bed dryer includes a solar collector and a fluidized bed. The fluidized bed has a feed inlet 7, a discharge outlet 9, an air inlet and an air outlet 8. The solar collector has an air inlet end 3-4 and an air outlet end 3-5.

[0023] The air outlet 3-5 of the solar collector is connected to the air inlet of the fluidized bed through a pipeline to provide heated air to the fluidized bed.

[0024] It also includes an ambient cold air bypass channel 5 connected to the fluidized bed air inlet and an auxiliary heating channel. The ambient cold air bypass channel is used to provide ambient cold air to the fluidized bed, and the auxiliary heating channel is equipped with an auxiliary heating device 11 to provide heated air to the fluidized bed.

[0025] Valve bodies are installed on the pipeline where the solar collector is located, the ambient cold air bypass channel 5, and the auxiliary heating channel. Temperature sensors are installed in the fluidized bed or at the air inlet to provide feedback and adjust the opening of the valve bodies.

[0026] In this application, by adding an ambient cold air bypass channel and an auxiliary heating channel, and supplementing them with temperature sensor monitoring, ambient cold air or auxiliary heating can be introduced adaptively when solar energy fluctuates, thereby ensuring that the gas temperature input into the fluidized bed remains within a certain range to guarantee the quality of grain drying.

[0027] The solar collectors and fluidized beds here are existing installations. The solar collectors are used to convert solar radiation into heat energy to heat the air, and the fluidized beds are used to support and dry the materials.

[0028] The auxiliary heating device 11 here refers to the use of other heating methods to achieve auxiliary heating when solar energy is weak, such as during cloudy or rainy weather, such as conventional electric heating. Thermistors or similar devices are installed within the auxiliary heating channel.

[0029] In this embodiment, an integrated bracket 1 is also provided for supporting and fixing other components.

[0030] The temperature sensor feedback valve opening can be controlled manually or automatically. Preferably, in this embodiment, temperature adjustment is achieved automatically by introducing a PLC control center 12.

[0031] Precise temperature control can prevent quality problems in heat-sensitive crops during drying, such as cracking of rice grains.

[0032] Specifically, it also includes a PLC control center 12, which is connected to the temperature sensor signal. The PLC control center 12 controls the opening of at least one valve in the pipeline where the solar collector is located, the ambient cold air bypass channel 5, and the auxiliary heating channel.

[0033] This setup creates an intelligent regulating air mixing system to adjust the temperature of the hot air entering the fluidized bed. In practice, a solar irradiance sensor can also be installed on the surface of the solar collector and connected to the PLC control center. The data from the irradiance sensor can be used as a feedforward control signal to predict temperature change trends in advance, making the control smoother and faster.

[0034] Specifically, when the drying temperature exceeds the required temperature, a signal is input to the PLC control center 12, and the temperature is reduced by adjusting the three-way regulating valve 4; when the drying temperature is lower than the required temperature, a signal is input to the PLC control center 12, and the temperature is increased by activating the heating auxiliary.

[0035] In practice, the airflow rate and material residence time can be adjusted through the PLC control center 12 to further achieve precise control of the drying process.

[0036] Furthermore, the valve body on the pipeline where the solar collector is located and the ambient cold air bypass channel 5 is a common three-way regulating valve 4, which is used to adjust the mixing ratio of hot air and ambient cold air. Figure 1 The valve body on the auxiliary heating channel is not shown. The PLC control center 12 can control the opening degree of each valve body and the auxiliary heating device 11.

[0037] In this embodiment, the fluidized bed is a vibrating fluidized bed.

[0038] Vibrating fluidized beds are a type of existing fluidized bed that introduces a vibration mechanism to generate regular vibrations during operation. This is particularly important for heat-sensitive crops that are prone to adhesion, have uneven particle size, or are difficult to fluidize. Vibration effectively breaks up particle agglomeration, reduces the minimum required fluidization velocity, further reduces energy consumption, and enhances drying uniformity.

[0039] The vibrating fluidized bed drying chamber is equipped with a gas distribution plate with uniform openings to support the material and allow hot air to pass through evenly. A conveyor belt 13 is installed on the plate, and one or more vibrating motors 10 are installed at the bottom. The vibration frequency is controlled by a frequency converter, which can also adapt to the fluidization requirements of different materials.

[0040] In this embodiment, the pipeline where the solar collector is located and the auxiliary heating channel share a single induced draft fan 2 as a power drive device.

[0041] Combination Figures 2-4 In this embodiment, the solar collector is a flat-plate solar collector 3, which includes a top glass cover plate 3-1, an inner heat-absorbing plate 3-2, and a bottom heat insulation layer 3-6.

[0042] The glass cover plate 3-1 has high light transmittance, the heat-absorbing plate 3-2 is coated with a heat-absorbing coating, and the heat insulation layer 3-6 is set at the bottom and sides of the solar collector. The heat insulation layer 3-6 is made of phenolic foam.

[0043] Flat-plate solar collector 3 is one type of existing solar collector that can utilize solar radiation energy to rapidly heat up under solar radiation.

[0044] In practice, the flat-plate solar collector 3 is installed on the top of the device or on the sun-facing side to convert solar radiation into heat energy to heat the air.

[0045] Reference Figure 3In this embodiment, the heat absorber plate 3-2 is configured as a baffle structure, and the hot air inlet 3-3 is shown in the figure, to increase the contact time and heat exchange area between the air and the heat absorber plate 3-2, thereby improving the heat collection efficiency. In practice, the heat absorber plate 3-2 can be configured as an S-shaped or wavy baffle structure. (Refer to...) Figure 4 The flat-plate solar collector 3 has an air inlet end 3-4 and an air outlet end 3-5. In this embodiment, the air inlet end 3-4 is connected to the induced draft fan 2, and the air outlet end 3-5 is connected to the fluidized bed.

[0046] In this embodiment, an observation window (not shown in the figure) is provided on the fluidized bed to facilitate external observation of the internal fluidization state. In practice, the observation window is made of tempered glass or other high-temperature resistant glass and is located on the front of the device.

[0047] In this embodiment, the air outlet 8 of the fluidized bed is connected to the discharge pipe 6. The discharge pipe 6 shares a portion of the pipe wall with the air inlet pipe leading to the solar collector or auxiliary heating device 11, and the shared pipe wall area uses heat exchange plate 6-1.

[0048] With this configuration, when the humid air in the fluidized bed drying chamber is discharged through the exhaust pipe 6, the waste heat can be transferred to the newly entering air, forming a semi-closed-loop thermal energy cascade utilization system, which further improves the overall thermal efficiency and energy utilization rate of the system.

[0049] In summary, the main advantages of this utility model are: it utilizes solar energy as the primary heat source, significantly reducing energy consumption and operating costs, thus being energy-saving and environmentally friendly; the airflow is uniformly heated by the solar collector, and the temperature is stabilized by PLC control, avoiding local overheating or undercooling and improving drying quality; the material in the vibrating fluidized bed is in full contact with the hot air, achieving high heat transfer efficiency and fast and uniform drying speed; the structure is reasonable, it can complement conventional energy sources, adapt to different weather conditions, and is highly practical.

[0050] The above equipment is used as follows: Start the induced draft fan 2 to introduce air, which is heated by the solar collector. The temperature of the hot air is adjusted by the intelligent air mixing system. The material enters the conveyor belt 13 in the vibrating fluidized bed drying chamber through the feed inlet 7. It is dried evenly under the action of vibration and hot air. The heat in the exhaust air is recovered through the heat exchange plate 6-1. After drying, the material is discharged through the discharge outlet 9 via the conveyor belt.

[0051] In this embodiment, when the device is applied to rice drying, the situation is as follows.

[0052] Harvest season is characterized by high humidity, with rice moisture content reaching as high as 28%, requiring rapid drying to below 15% to prevent mold. Traditional sun-drying methods require a large area and are easily affected by weather.

[0053] Drying rice: First, start the induced draft fan 2, check the normal operation of the device, check that the pipeline is clean, observe the initial temperature on the control panel, and place the harvested rice into the fluidized bed through the feed inlet 7. Specific drying process parameters are shown in Table 1. Table 1 Drying process parameters Within this temperature range, drying continues, and after drying is completed, the dried rice is harvested from outlet 9 and stored.

[0054] Table 2 Required drying time at different temperatures In practice, with the above parameter settings and process parameters, rice can achieve better drying quality.

[0055] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A solar-powered fluidized bed dryer, characterized in that, It includes a solar collector and a fluidized bed. The fluidized bed has a feed inlet (7), a discharge outlet (9), an air inlet and an air outlet (8). The solar collector has an air inlet end (3-4) and an air outlet end (3-5). The air outlet end (3-5) of the solar collector is connected to the air inlet of the fluidized bed through a pipeline to provide heated air to the fluidized bed; It also includes an ambient cold air bypass channel (5) connected to the fluidized bed air inlet and an auxiliary heating channel. The ambient cold air bypass channel is used to provide ambient cold air to the fluidized bed, and the auxiliary heating channel is equipped with an auxiliary heating device (11) to provide heated air to the fluidized bed. Valve bodies are installed on the pipeline where the solar collector is located, the ambient cold air bypass channel (5), and the auxiliary heating channel. Temperature sensors are installed in the fluidized bed or at the air inlet to provide feedback and adjust the opening of the valve body.

2. The solar-powered fluidized bed dryer as described in claim 1, characterized in that, It also includes a PLC control center (12), which is connected to a temperature sensor signal. The PLC control center (12) controls the opening of at least one valve in the pipeline where the solar collector is located, the ambient cold air bypass channel (5), and the auxiliary heating channel.

3. The solar-powered fluidized bed dryer as described in claim 2, characterized in that, It also includes a solar irradiance sensor installed on the solar collector, and the solar irradiance sensor and the PLC control center (12) are connected by signal.

4. The solar-powered fluidized bed dryer as described in claim 1, characterized in that, The valve body on the pipeline where the solar collector is located and the ambient cold air bypass channel (5) is a common three-way regulating valve (4).

5. The solar-powered fluidized bed dryer as described in claim 1, characterized in that, The fluidized bed is a vibrating fluidized bed.

6. The solar-powered fluidized bed dryer as described in claim 1, characterized in that, The pipeline where the solar collector is located and the auxiliary heating channel share a single induced draft fan (2) as the power drive device.

7. The solar-powered fluidized bed dryer as described in claim 1, characterized in that, The solar collector is a flat-plate solar collector, which includes a top glass cover (3-1), an internal heat-absorbing plate (3-2), and a bottom insulation layer (3-6).

8. The solar-powered fluidized bed dryer as described in claim 7, characterized in that, The heat absorber plate (3-2) is configured with a baffle structure to increase the residence time of air in the solar collector.

9. The solar-powered fluidized bed dryer as described in claim 1, characterized in that, An observation window is provided on the fluidized bed to facilitate external observation of the interior.

10. The solar-powered fluidized bed dryer according to any one of claims 1-9, characterized in that, The air outlet (8) of the fluidized bed is connected to the discharge pipe (6). The discharge pipe (6) shares a portion of the pipe wall with the air inlet pipe leading to the solar collector or auxiliary heating device (11), and the shared pipe wall area uses a heat exchange plate (6-1).

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