CN103145310B - Sludge drying system combining solar energy and multi-heat-source heat pump - Google Patents

Abstract

The invention relates to a sludge drying system combined with solar energy and a multi-heat source heat pump, and belongs to the technical field of sludge drying. In order to improve the energy utilization rate of solar sludge drying technology, the system provided includes: solar house warming system, including a house warming enclosure module, a floor module and a gas diversion module; the house warming enclosure module constitutes the outer frame of the house warming system, The bottom plate module carries the sludge to be dried, and the gas diversion module imports hot air from the outside to the inside of the warm house system and discharges the humid air inside the warm house system; the heat pump subsystem is connected with the gas diversion module, and through the gas diversion The flow module introduces hot air into the heating system and dehumidifies the humid air exhausted from the heating system. The system uses solar greenhouses for sludge drying, which is easy to maintain and has high reliability. It also has a compact structure and uses heat pumps for heating and dehumidification, thereby improving pollution. Energy utilization rate of mud drying process.

Description

Sludge drying system combined with solar energy and multi-heat source heat pump

technical field

The invention belongs to the technical field of sludge drying and relates to a sludge drying system combined with solar energy and multi-heat source heat pumps. the

Background technique

Sludge drying is an important part of municipal sewage treatment, and it is also a process that consumes a lot of energy. Reducing the moisture content of sludge through drying treatment can achieve the purpose of resource utilization, stabilization, reduction and harmlessness. At present, there is a technical idea of using solar energy to dry sludge. Since abundant solar energy resources can be used free of charge, a large amount of conventional energy can be saved, which has great economic and environmental benefits. the

Among them, the main characteristics of solar energy utilization include:

(1) Universality: The sun shines on the earth, no matter land or sea, no matter mountains or islands, it is everywhere, can be directly developed and utilized, and does not need to be mined and transported;

(2) Non-pollution: the development and utilization of solar energy will not pollute the environment, it is one of the cleanest energy sources, and this is extremely valuable in today's increasingly serious environmental pollution;

(3) Enormous energy: the solar radiant energy that reaches the earth's surface every year is equivalent to about 130 trillion tons of standard coal, and its total amount is the largest energy that can be developed in the world today;

(4) Persistence: According to the estimation of the current rate of nuclear energy produced by the sun, the storage of hydrogen is enough to last tens of billions of years, and the life of the earth is also about several billion years. In this sense, it can be said that the energy of the sun is Inexhaustible. the

But at the same time, under the current existing technical conditions, the application of solar energy also has the following defects:

(1) Dispersion: Although the total amount of solar radiation reaching the earth's surface is large, the energy flux density is very low. On average, near the Tropic of Cancer, when the weather is relatively clear in summer, the irradiance of solar radiation is the largest at noon, and the average solar energy received on an area of 1 square meter perpendicular to the direction of sunlight is about 1000W; The average day and night throughout the year is only about 200W. In winter, it is roughly half, and in cloudy days, it is generally only about 1/5, so the energy-flux density is very low;

(2) Instability: Due to the limitation of natural conditions such as day and night, season, geographical latitude and altitude, as well as the influence of random factors such as sunny, cloudy, cloud and rain, the solar irradiance reaching a certain ground is intermittent And it is extremely unstable, which increases the difficulty for the large-scale application of solar energy. the

Based on the above reasons, it is precisely because of the shortcomings of solar energy such as low energy flow density, discontinuity, and strong weather influence, so only using solar energy cannot guarantee the required amount of sludge treatment within a period of time. Therefore, how to use solar energy more reasonably and effectively for sludge drying treatment is a very valuable subject and technology to be perfected in the current municipal sewage treatment system. the

Contents of the invention

(1) Technical problems to be solved

The technical problem to be solved by the invention is how to improve the energy utilization rate of the solar sludge drying technology. the

(2) Technical plan

In order to solve the above technical problems, the present invention provides a sludge drying system combined with solar energy and multi-heat source heat pumps, including:

A solar energy warming system, which includes a greenhouse enclosure module, a floor module and a gas diversion module; the greenhouse enclosure module constitutes the external frame of the solar energy warming system, and the floor module is used to carry sludge to be dried , the gas diversion module is used to introduce hot air from the outside to the inside of the solar heating system and discharge the humid air inside the solar heating system;

The heat pump subsystem, its heat source includes external ambient air and reclaimed water, is connected to the gas diversion module, and is equipped with an evaporator group, an expansion valve group, a condenser, a fixed-frequency compressor and corresponding pipelines. A closed circulation system is used to introduce hot air into the solar house warming system through the gas guide module and dehumidify the humid air discharged from the solar house warming system. the

Wherein, the greenhouse enclosure module includes an enclosure structure composed of thermal insulation materials with selective transmittance to sunlight. the

Wherein, the bottom plate module includes two layers, the lower layer is an insulation layer, and the upper layer is a sludge bearing layer. the

Wherein, the solar house warming system further includes a thermal insulation film layer, the thermal insulation film layer is arranged above the greenhouse enclosure module, and the thermal insulation film layer is connected with a driving device for spreading or retracting it. the

Wherein, the solar energy warming system also includes a mud turning module, the mud turning module is arranged above the sludge layer, and a rotating drum is arranged in the center of the rotating drum, and a threaded comb is fixedly installed on the rotating drum, and is connected to a driving motor Driven by a motor, it can rotate and move in a linear direction. the

Wherein, the gas diversion module includes an axial flow fan, a greenhouse air outlet and a greenhouse air inlet. the

Wherein, the first expansion valve of the expansion valve group is arranged in series with the first evaporator of the evaporator group, the second expansion valve of the expansion valve group is arranged in series with the second evaporator of the evaporator group, The third expansion valve of the expansion valve group is arranged in series with the third evaporator of the evaporator group, thereby forming three sets of sub-pipelines in series. the

Wherein, the three groups of series sub-pipelines are arranged in parallel to form parallel sub-pipelines. the

Wherein, the parallel sub-pipelines are arranged in series with the condenser and the fixed-frequency compressor, and the formed pipelines communicate with the greenhouse air outlet and the greenhouse air inlet of the gas diversion module respectively. the

(3) Beneficial effects

Compared with the prior art, the technical solution of the present invention has the following characteristics:

(1) The present invention uses a solar greenhouse as a place for sludge drying, which is easy to maintain and has high reliability, and uses the gas diversion module to perform the work of expelling moisture and transporting hot air between the heat pump subsystem, and the system has a compact structure , and use the heating and dehumidification functions of the heat pump to improve the energy utilization rate of the sludge drying process. the

(2) Further, the present invention adopts a heat pump subsystem that makes full use of the air and water heat energy in the sewage plant, and can complete the heating and dehumidification functions by using a fixed-frequency compressor, which only needs to consume a small amount of electric energy or fuel energy. Turn the exhaust gas in the drying greenhouse or the large amount of free heat contained in the surrounding environment into high-temperature heat energy that meets the requirements for heating the intake air of the greenhouse. The useful heat energy produced is always greater than the electrical energy or fuel energy it consumes. That is, the thermal efficiency of the heat pump subsystem is always greater than 1, thereby further realizing energy saving and improving energy utilization rate. the

(3) Furthermore, according to the structural setting of the heat pump subsystem, the efficient operation of the sludge drying system in different seasons and different heat sources can be realized throughout the year. In order to overcome the various deficiencies caused by solar energy itself in the existing solar energy utilization process, so as to meet the heat load requirements required for sludge treatment, and use solar energy, external air heat sources and reclaimed water heat sources as much as possible, therefore, Obviously, the energy utilization rate is further improved. the

Description of drawings

Fig. 1 is a schematic structural diagram of a sludge drying system combined with solar energy and multi-heat source heat pumps provided by the present invention. the

in:

1. Heating room exhaust outlet; 2. Fan; 3. Evaporator; 4. Evaporator; 5. Water pump; 6. Water inlet; 7. Evaporator; 8. Fan; 9. Outdoor air inlet; 10. Outdoor Atmospheric air outlet; 11. Fixed frequency compressor; 12. Expansion valve; 13. Water outlet; 14. Expansion valve; 15. Expansion valve; 16. Condenser; 17. Heating air inlet; 18. Driving device; 19. Insulation film layer; 20. Enclosure structure; 21. Axial flow fan; 22. Mud turning module; 23. Sludge layer; 24. Sludge bearing layer; 25. Insulation layer. the

Fig. 2 is a schematic diagram of the sludge drying system of the present invention when the heat pump subsystem using ambient air as the heat source operates. the

Fig. 3 is a schematic diagram of the sludge drying system of the present invention under the operation of the heat pump subsystem using reclaimed water as the heat source. the

Fig. 4 is a system schematic diagram of the sludge drying system of the present invention in a dehumidification operating state. the

Detailed ways

In order to make the purpose, content and advantages of the present invention clearer, the specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. the

In order to improve the energy utilization rate of solar sludge drying technology, the present invention provides a sludge drying system combined with solar energy and multi-heat source heat pump, as shown in Figure 1, the system includes: solar energy warming system and heat pump subsystem ;in,

The solar house warming system includes a house warming enclosure module, a bottom plate module, a gas diversion module, a thermal insulation film layer 19 and a mud turning module 22 . the

The house-warming enclosure module constitutes the outer frame of the solar house-warming system, which includes an enclosure structure 20 composed of a thermal insulation material that is selectively transparent to sunlight, and the thermal insulation material is preferably glass or plastic film or polyester. Carbonate hollow board, when the sun shines on this kind of material, because the penetration ratio of this kind of material to small wavelength, such as radiant energy with a wavelength below 2.2μm is very large, so that most of the solar energy can enter the greenhouse. At the same time, due to the low temperature of objects in the greenhouse, most of its radiant energy is located in the infrared range with a wavelength greater than 3 μm. However, the glass or plastic film has a very small penetration ratio for radiant energy with a wavelength greater than 3 μm, thereby preventing the radiant energy from being lost to the outside of the greenhouse. Therefore, solar greenhouses are used as sludge drying places. On the one hand, most of the solar energy can pass through them into the greenhouse, and on the other hand, it can prevent the radiant energy of objects in the greenhouse from dissipating outside the greenhouse, thereby achieving the effect of heat preservation. the

The bottom plate module is located on the bottom surface of the greenhouse and is used to carry the sludge to be dried. It is divided into upper and lower layers. The lower layer is preferably an insulation layer 25 paved with polystyrene boards, which can effectively prevent a large amount of heat from being lost through the ground. The upper layer is a sludge bearing layer 24 preferably made of concrete, on which the sludge layer 23 to be dried is placed. the

The air diversion module is used to introduce hot air from the outside to the inside of the solar heating system and discharge the humid air inside the solar heating system; the

Described thermal insulation film layer 19 is arranged on the above described greenhouse enclosure module, and described thermal insulation film layer 19 is connected with the driving device 18 that is used to spread out or pack up. Preferably, the thermal insulation film layer 19 is a thermal insulation quilt, and the driving device 18 is a roller blind machine; when the thermal insulation is retracted, it is wrapped on the electric bearing of the roller blind machine, allowing sunlight to directly pass through the enclosure during the day. The structure 20 heats the air in the conservatory. The heated air is continuously sent to the top of the sludge layer 23 through the axial flow fan 21 installed in the middle of the greenhouse, and exchanges heat and moisture with the sludge layer 23 . In the evening, the thermal insulation is spread out by operating the shutter machine and covered on the outside of the enclosure structure 20, which can effectively reduce the heat loss in the greenhouse and delay the cooling speed of the indoor air. the

In order to strengthen the heat and moisture exchange process between sludge and air, a mud turning module 22 is also arranged in the greenhouse, and the mud turning module 22 is arranged on the top of the sludge layer 23, and a rotating cylinder is arranged at the center of the rotating cylinder, and a rotating cylinder is fixed on the rotating cylinder. A threaded comb is installed to turn the sludge, and a frequency drive motor is connected to perform self-rotation and linear movement under the control of the motor drive. the

The heat pump subsystem is connected with the air guiding module, and is used for introducing hot air into the solar heating system through the gas guiding module and dehumidifying the humid air discharged from the solar heating system. the

Wherein, the heat source of the heat pump subsystem includes external ambient air and reclaimed water, which includes a closed cycle system composed of an evaporator group, an expansion valve group, a condenser 16, a fixed-frequency compressor 11 and corresponding pipelines. The evaporator group includes evaporator 3 , evaporator 4 and evaporator 7 ; the expansion valve group includes expansion valve 12 , expansion valve 14 and expansion valve 15 . the

Wherein, the expansion valve 15 is arranged in series with the evaporator 3, the expansion valve 14 of the expansion valve group is arranged in series with the evaporator 4, and the expansion valve 12 is arranged in series with the evaporator 7, thereby forming Three groups of sub-pipes in series, then, the three groups of sub-pipes in series are arranged in parallel to form parallel sub-pipes, and finally, the parallel sub-pipes are arranged in series with the condenser 16 and the fixed-frequency compressor 11, and the formed pipeline is connected with the described The air outlet 1 and the air inlet 17 of the gas diversion module are respectively communicated with each other. the

Below, the working process of the system will be described in detail with reference to the accompanying drawings. the

In order to ensure that the required amount of sludge treatment is completed within a period of time, sufficient heat must be input at one time at the beginning of the drying process. Therefore, in addition to solar energy providing part of the heat load, the present invention is also provided with a heat pump subsystem as an auxiliary heat source to improve energy utilization efficiency. Next, the workflow of the system will be described according to different application situations. the

First of all, in the summer of our country, when the ambient air temperature is higher than the temperature of the water in the sewage treatment plant, the air source heat pump subsystem operates. As shown in Figure 2, turn on fan 2 and fan 8, respectively discharge humid air from the greenhouse and introduce hot air from the outside, then open expansion valve 12, and keep expansion valve 14 and expansion valve 15 in a closed state. At this time, the outdoor air is continuously sucked into the evaporator 7 for dehumidification, and the refrigerant in the evaporator 7 absorbs the heat in the atmosphere and evaporates, changing from a low-temperature and low-pressure liquid to a low-temperature and low-pressure gas, which is boosted by the fixed-frequency compressor 11 Then it becomes a high-temperature and high-pressure gas. In the condenser 16, the high-temperature and high-pressure refrigerant gas releases heat to heat the air in the greenhouse. The working medium itself condenses into a liquid, and after being throttled by the expansion valve 12, it becomes a low-temperature and low-pressure liquid that enters evaporation. Device 7 starts the next cycle. The air in the greenhouse is heated and sent to the dried sludge layer 23 . the

Then, in winter in our country, when the ambient air temperature is lower than the temperature of the water in the sewage treatment plant, the heat pump subsystem using the reclaimed water as the heat source operates. As shown in FIG. 3 , the fan 2 and the water pump 5 are turned on, the expansion valve 14 is opened, and the expansion valve 12 and the expansion valve 15 are kept closed. At this time, the reclaimed water is continuously sent to the evaporator 4 through the water pump 5, and the refrigerant in the evaporator 4 absorbs the heat in the reclaimed water and evaporates, changing from a low-temperature and low-pressure liquid to a low-temperature and low-pressure gas, and then passes through a fixed-frequency compressor for 11 liters. After being compressed, it becomes a high-temperature and high-pressure gas. In the condenser 16, the high-temperature and high-pressure refrigerant gas releases heat to heat the air in the greenhouse. The working medium itself condenses into a liquid, which becomes a low-temperature and low-pressure liquid after being throttled by the expansion valve 14. Evaporator 4 starts the next cycle. The air in the greenhouse is heated and sent to the dried sludge layer 23 . The use of reclaimed water as the low-temperature heat source of the heat pump is because the quality of reclaimed water is better than that of sewage, which has little corrosion on the heat pump evaporator and slow scaling, which is conducive to long-term reliable operation of the system. the

It can be seen that, no matter in summer or winter, the heat pump can always be operated with a small temperature difference between high and low temperature heat sources, which improves the energy utilization rate of the solar drying system. the

In addition, when the air supply temperature of the heating air inlet 17 reaches the set value and the heating needs to be dehumidified, the operation state of the heat pump subsystem is switched to the dehumidification operation mode, as shown in Figure 4, and the expansion valve 15 is opened to make the expansion valve 12 and The expansion valve 14 is in the closed state, the humid air discharged from the greenhouse is continuously sucked into the evaporator 3 for dehumidification, and the refrigerant in the evaporator 3 absorbs the heat in the humid air and evaporates, changing from a low-temperature and low-pressure liquid to a low-temperature and low-pressure gas After being boosted by the fixed-frequency compressor 11, it becomes a high-temperature and high-pressure gas. In the condenser 16, the high-temperature and high-pressure refrigerant gas releases heat to heat the dehumidified air. Finally, the low-temperature and low-pressure liquid enters the evaporator 3 to start the next cycle. The air in the greenhouse is heated and sent to the dried sludge layer 23, thereby improving the energy utilization rate by continuously recovering the heat in the exhaust gas of the greenhouse. the

To sum up, the sludge drying system combined with solar energy and multi-heat source heat pump proposed by the present invention fully utilizes the heat energy of air and water in the sewage plant, and can complete the heating and dehumidification of the heat pump by using a fixed-frequency compressor to work function, the system is compact, and it is easy to realize the efficient operation of the sludge drying system throughout the year. The solar greenhouse is used as the place for sludge drying, which is easy to maintain and has high reliability. The energy saving of the whole system is obvious, and the energy utilization rate has been greatly improved. the

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and modifications can also be made. It should also be regarded as the protection scope of the present invention. the

Claims (7)

1. A sludge drying system combining solar energy and a multi-heat-source heat pump is characterized by comprising:

the solar greenhouse system comprises a greenhouse enclosure module, a bottom plate module and a gas guide module; the greenhouse enclosure module forms an external framework of the solar greenhouse system, the bottom plate module is used for bearing sludge to be dried, and the gas guide module is used for guiding hot air from the outside to the interior of the solar greenhouse system and discharging wet air in the interior of the solar greenhouse system;

the heat pump subsystem is connected with the gas diversion module, is internally provided with a closed circulating system consisting of evaporator groups (3, 4 and 7), expansion valve groups (12, 14 and 15), a condenser (16), a fixed-frequency compressor (11) and corresponding pipelines, and is used for introducing hot air into the solar energy house-warming system through the gas diversion module and dehumidifying humid air exhausted from the solar energy house-warming system;

wherein first expansion valve (15) of expansion valve group with first evaporimeter (3) series connection of evaporimeter group sets up second expansion valve (14) of expansion valve group with second evaporimeter (4) series connection of evaporimeter group sets up third expansion valve (12) of expansion valve group with third evaporimeter (7) of evaporimeter group set up in series connection to form three group's series connection subducts, three group's series connection subducts are parallelly connected to be set up, form parallelly connected subducts.

2. The combined solar and multi-heat source heat pump sludge drying system of claim 1 wherein the greenhouse enclosure module comprises an enclosure (20) comprised of insulation material that is selectively transparent to sunlight.

3. The combined solar and multi-heat-source heat pump sludge drying system of claim 1, wherein the floor module comprises two layers, the lower layer is an insulating layer (25), and the upper layer is a sludge bearing layer (24).

4. The sludge drying system combining solar energy and a multi-heat-source heat pump as claimed in claim 1, wherein the solar house warming system further comprises a heat insulation film layer (19), the heat insulation film layer (19) is disposed above the house warming enclosure module, and the heat insulation film layer (19) is connected with a driving device (18) for spreading or retracting the heat insulation film layer.

5. The sludge drying system combining the solar energy and the multi-heat-source heat pump as claimed in claim 1, wherein the solar energy house-warming system further comprises a sludge turning module (22), the sludge turning module (22) is disposed above the sludge blanket (23), a rotating drum is disposed at a central portion of the sludge blanket, a thread comb is fixedly mounted on the rotating drum, and the rotating drum is connected with a driving motor to rotate and move in a linear direction under the driving of the motor.

6. The combined solar and multi-heat-source heat pump sludge drying system of claim 1, wherein the gas diversion module comprises an axial flow fan (21), a greenhouse air outlet (1) and a greenhouse air inlet (17).

7. The solar energy and multi-heat-source heat pump combined sludge drying system according to claim 6, wherein the parallel sub-pipeline is connected in series with the condenser (16) and the constant-frequency compressor (11), and the formed pipeline is respectively communicated with the greenhouse air outlet (1) and the greenhouse air inlet (17) of the gas diversion module.

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