WO2017121260A1

WO2017121260A1 - Drying system combining hot air drying and cold air drying

Info

Publication number: WO2017121260A1
Application number: PCT/CN2016/113998
Authority: WO
Inventors: 陈义龙; 胡书传; 张岩丰
Original assignee: 中盈长江国际新能源投资有限公司
Priority date: 2016-01-14
Filing date: 2016-12-31
Publication date: 2017-07-20
Also published as: CN105627700B; CN105627700A

Abstract

A drying system combining hot air drying and cold air drying comprises a solar greenhouse (1), an air condenser (2), a water-bath deduster (9), a heat source, an air heater (4), a smoke refrigerating device, an air cooler (8), pipes connected to the devices, and valves (13.1-13.5) and a fan (7.1-7.6) disposed on the pipes. The solar greenhouse (1) is a sealed structure, and the air condenser (2) is a cylindrical structure. The heat source is connected to the air heater (4). An air inlet of the solar greenhouse (1), an air outlet of the air condenser (2) and an outlet of the air heater (4) communicate with one another by means of the pipes. An air outlet of the solar greenhouse (1) communicates with an air box (2.1) above the air condenser (2) by means of the pipe. A smoke outlet of the air heater (4) is connected to the smoke refrigerating device. Energy is utilized at multiple levels on the system, thereby improving the thermal efficiency of drying.

Description

Dry system combining hot air and cold air drying

Technical field

The invention belongs to a drying technology using solar energy, in particular to a drying system combining hot air and cold air drying.

Background technique

In recent years, the global energy crisis and the resulting “competition war” of energy have gradually escalated. At the same time, the energy structure dominated by conventional energy sources such as coal, oil and natural gas continues, but many of them carry heat during the application process. The exhaust gas is discharged into the atmosphere, which wastes energy and pollutes the environment. To this end, the development of new energy has been booming in recent years, but the focus is on industrial projects and cities. The agricultural sector is only used in solar greenhouses, and other aspects have not made much progress.

Solar energy also has a vast world in the countryside, and the quality of life of farmers needs to be greatly improved. Farmers also need to get rich quickly. There are many products in the countryside that need to be dried, such as dried mango, dried fruit and other fruits, rice, wheat, corn, soybeans, rapeseed, candied fruit, seaweed, agar, tea, broccoli and other agricultural products, sea cucumber, abalone, squid , shark's fin, squid, willow fish, palladium fish, squid, salmon and shrimp, shellfish, all kinds of river fresh fish and other aquatic products, dried duck meat, dried meat, etc., including straw, twigs, bark Agricultural waste such as roots. Drying these agricultural products, aquatic products, and wastes in the production process of agroforestry can reduce the cost of storage and transportation of these materials and commodities, and improve the economic benefits of rural areas. However, if traditional energy is used, not only high cost, but also low thermal efficiency and environmental pollution. .

Summary of the invention

The technical problem to be solved by the invention is to provide a drying system combining hot air and cold air drying, which can completely dry the solar energy and the hot and cold air for different materials, and realize multi-level utilization of energy and improve The thermal efficiency of drying.

In order to solve the above technical problems, the present invention provides a drying system combining hot air and cold air drying, including a solar greenhouse, an air condenser, a water bath dust collector, a heat source, an air heater, a flue gas refrigeration device, a cooling fan, and a connection. Valves and fans installed on pipes and pipes of each device;

The solar greenhouse is a sealed structure, the building structure is a frame structure, the top surface and the three sun-facing surfaces are composed of PC sunlight board, tempered glass, plexiglass or FRP lighting board, and the non-sun surface is an energy storage wall, and the solar greenhouse floor For the concrete perforated plate, the concrete perforated plate is arranged above the ground, above which is used for placing the material to be dried, and below for ventilation;

The air condenser has a cylindrical structure, and the air inlet and outlet are opened on the side of the cylinder for air in and out, and the upper and lower nozzles are respectively provided with air boxes, and the two air boxes are connected through the air tube bundle for being used for cooling. gas;

The heat source is connected to the air heater for heating the gas introduced into the air heater by using the flue gas;

There is an air inlet under the floor of the solar greenhouse, and an air outlet above the floor. The air inlet of the solar greenhouse, the air outlet of the air condenser and the outlet of the air heater are connected through the pipeline, and the air outlet and air condenser of the solar greenhouse The upper air box is connected by a pipeline, and the lower air box of the air condenser is connected to the water bath dust remover;

The flue gas outlet of the air heater is connected to the flue gas refrigeration device for preparing chilled water by using flue gas heat;

The water inlet and the water outlet of the flue gas refrigeration device are respectively connected with the water outlet and the water inlet of the air cooler for cooling and dehumidifying the air that is introduced into the air cooler.

In the above technical solution, the energy storage wall of the solar greenhouse is composed of aerated concrete and rock wool insulation layer masonry plus energy storage mixed mortar, or hollow brick masonry filled with energy storage mixed mortar, the energy storage mixing The phase change heat of the mortar is not less than 60kj/kg.

In the above technical solution, the indoor surface of the solar greenhouse is coated with a far infrared reflective coating.

In the above technical solution, the air condenser and the air tube bundle therein are made of steel, and the surface of the air pipe is coated with an anticorrosive paint.

In the above technical solution, the heat source is a hot air furnace, and in the factory and the power plant, preheating and waste heat in the flue gas are used as much as possible.

In the above technical solution, the flue gas refrigeration device is a flue gas lithium bromide refrigerator.

In the above technical solution, the air outlet of the air cooler is in communication with the air inlet of another solar greenhouse.

In the above technical solution, the solar greenhouse is a micro-pressure chamber, and the pressure is 30,000 to 70,000 Pa, preferably 50,000 Pa.

Compared with the prior art, the invention has the beneficial effects that the structurally optimized solar greenhouse can fully utilize the solar energy to preheat and dry the material, which not only saves energy but also ensures the dry quality; the use of the high heat source and the air heater can The high-level energy can be used for forced drying at high temperature, and the two methods of forced convection and radiation drying are effectively combined. At the same time, the residual heat of the heat source is used for cold air drying, which realizes multi-stage utilization of energy and improves thermal efficiency. The thermal efficiency is generally 60. ~70% or so; the whole system can be dried by hot air or cold air according to the needs of different kinds of materials, and the application range is wide.

DRAWINGS

1 is a schematic view showing the structure and working principle of an embodiment of the present invention;

2 is a schematic structural view of the solar greenhouse of FIG. 1;

Figure 3 is a schematic structural view of the air condenser of Figure 1;

Figure 4 is a cross-sectional view taken along line A-A of Figure 3;

In the picture: 1 - solar greenhouse (where: 1.1 - PC sunlight board, 1.2 - energy storage wall, 1.3 - concrete perforated board), 2 - air condenser (of which: 2.1 - air box, 2.2 - air tube, 2.3 - condenser Enclosure), 3—hot air stove, 4—air heater, 5—flue gas bromide refrigerator, 6.1～6.3—pump, 7.1～7.6—fan, 8-cooler, 9—water bath dust collector, 10 - dehydrator, 11 - cooling tower, 12 - material, 13.1 ~ 13.15 - valve.

detailed description

The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings:

As shown in FIG. 1, a drying system combining the hot air and the cold air drying of the present invention comprises a solar greenhouse 1, an air condenser 2, a water bath dust collector 9, a heat source, an air heater 4, a flue gas refrigeration device, and a cooling fan. 8. Cooling tower 11, dehydrator 10, and valves 13.1 to 13.15 and fans 7.1 to 7.6 provided on pipes and pipes connecting the devices. details as follows:

As shown in Fig. 2, the solar greenhouse 1 has different orientations depending on the region. In principle, the front side should face the strongest direction of solar radiation, and in the northern hemisphere, it is generally facing south. The building structure of the solar greenhouse 1 is a frame structure, and the top surface and the east, west and south sides are composed of a PC solar panel 1.1. The physical characteristics of PC Sunshine Board 1.1 are: high strength (the impact resistance is 40 times that of glass, 20 times that of FRP), the light transmittance is up to 90%, the heat preservation performance is good (two times that of glass), and the weight is light ( It is 1/5) of glass, flame retardant and not easy to dew. The north side is the non-receiving side of the energy storage wall 1.2, and the energy storage wall 1.2 is composed of aerated concrete and rock wool insulation layer and additional energy storage mixed mortar, or it is composed of hollow brick filling and mixing mortar. The energy storage mixed mortar here can be made by mixing graphite powder, biomass power plant ash, cement mortar and water at the construction site, and the phase change heat is not less than 60kj/kg. A typical solar building or structure is generally a triangular roof shape or an arch shape. This embodiment is preferably a single-sided large sloped top surface capable of increasing the solar heat receiving area. The floor of the solar greenhouse 1 is a concrete perforated plate 1.3, and the concrete perforated plate 1.3 is placed about one meter above the ground, above which is used for placing the material 12 to be dried, and below is a ventilation duct for ventilation. In order to enhance the heat storage effect, the inner surface of the energy storage wall 1.2 and the surface of the concrete perforated plate 1.3 may be smeared with a storage mixing mortar of about 20 mm thick. The east and west sides of the solar greenhouse 1 (the sides parallel to the paper surface in Fig. 1) each open a sealing door for the placement and removal of the material 12, the solar greenhouse 1 does not open the window, and its steel structure and PC sunlight Sealing is required at the seam of the panel 1.1 to ensure the tightness of the entire solar greenhouse 1. The indoor surface of the solar greenhouse 1 is coated with a far-infrared reflective coating to make the indoor heat storage effect good and the temperature uniform.

As shown in FIG. 3 and FIG. 4, the condenser casing 2.3 has a cylindrical structure, the cylinder side is provided with air inlet and outlet, and is used for air in and out, and the upper and lower nozzles are respectively provided with a gas box 2.1, two The gas box 2.1 is connected by a bundle of gas tubes 2.2 for introducing gas to be cooled. Considering that the high temperature and high humidity gas has certain corrosiveness, the air condenser 2 and the gas tube 2.2 in the bundle are made of steel, and the surface of the gas pipe 2.2 is coated with three layers of anticorrosive paint. Thus, the high-temperature and high-humidity gas flows at a high speed in the tracheal bundle 2.2, and the normal-temperature air flows outside the bundle of the trachea 2.2. After the heat exchange, the condensed water is discharged, and the air is heated at room temperature and then used for drying in the solar greenhouse 1.

The water bath precipitator 9 is used to remove dust from the gas, and the efficiency can reach more than 99%.

The heat source can be a conventional boiler or the like, or a hot blast stove can be used. This embodiment is mainly for agricultural products in rural areas. The agricultural and sideline products and the biomass fuel are dried, so the heat source is preferably the hot air furnace 3. The hot air furnace 3 has a simple structure, low fuel requirements, and low use cost, and the flue gas temperature can reach 700-800 ° C, and the heated air temperature It can exceed 200 ° C, so it is very suitable for the application of the present invention. At the same time, in the present embodiment, the hot air oven 3 and the air heater 4 are integrated into one body, which can save land occupation.

In the flue gas refrigeration device of the present embodiment, the flue gas lithium bromide refrigerator 5 is preferably used in combination with the hot air furnace 3, and when the temperature of the flue gas discharged from the hot air furnace 3 exceeds 400 ° C, the flue gas lithium bromide refrigerator 5 can be prepared 5 ～7 ° C of chilled water.

The cooling tower 11 is in communication with the cooling water pipe of the flue gas lithium bromide refrigerator 5 for cooling of the flue gas lithium bromide refrigerator 5.

The structure of the air cooler 8 in this embodiment is similar to that of the conventional air heater, except that the chilled water flowing in the coil is 5 to 7 ° C. The air outlet of the air cooler 8 is in communication with the air inlet of the other solar greenhouse 1 for cold air drying of the material 12 in the solar greenhouse 1, and the air outlet of the solar greenhouse 1 is connected to the water heater 10.

The dehydrator 10 condenses high-temperature and high-humidity gas with chilled water to achieve dehydration purposes.

The device connection of the whole drying system is also shown in Fig. 1. The solar greenhouse 1 has an air inlet under the floor and an air outlet above the floor, so that the airflow direction in the solar greenhouse conforms to the law of rising hot air flow, and the solar greenhouse 1 The air inlet, the air outlet of the air condenser 2 and the outlet of the air heater 4 are connected by a pipe, and the air outlet of the solar greenhouse 1 is connected to the upper air box 2.1 of the air condenser 2 via a pipe, and the air box of the air condenser 2 is below. 2.1 is connected to the water bath dust collector 9. The flue gas outlet of the air heater 4 is connected to the flue gas inlet of the flue gas lithium bromide refrigerator 5, and the water inlet and the water outlet of the flue gas lithium bromide refrigerator 5 are respectively connected with the water outlet and the water inlet of the chiller 8, for cold air The air introduced into the machine 8 is cooled and dehumidified. Since the other solar greenhouse 1 connected to the air outlet of the air cooler 8 is cooled by cold air, the upper side of the floor of the solar greenhouse 1 is an air inlet, and the bottom of the floor is an air outlet. The necessary places on the pipeline are valves 13.1～13.15, pumps 6.1～6.3 and fans 7.1～7.6, which are used to realize different working conditions; the corresponding position of solar greenhouse 1 can also be set up with temperature gauge, pressure gauge and other measuring instruments. Monitoring and operation of the working state in the control room.

The working principle of the invention is as follows:

Solar greenhouse 1 preheating drying process:

1.1) During the day, after the material 12 to be dried is installed in the upper solar greenhouse 1 in FIG. 1, the sealing door is closed, so that the solar greenhouse 1 is in a sealed state;

1.2) Start fan 7.1, open valve 13.3, 13.4, other valves and fans are in the closed state, continuously pumping air, pumping the air pressure in solar greenhouse 1 to about 50000Pa, that is, the dehydration rate of material 12 in this state It is 15-20% more than under normal pressure, so that solar energy can be used more effectively;

1.3) When the pressure gauge of the control room shows that the indoor pressure of the solar greenhouse 1 is 50000Pa, the fan 7.1 is turned off. And close all valves to keep the room in a closed state. If the outdoor air permeates into the room and raises the pressure in the room, when the pressure is ≥60000Pa, repeat the operation of 1.2) to 1.3) to ensure that the indoor pressure is ≤50000Pa, which can ensure the effect of preheating and drying the solar energy.

1.4) As the solar greenhouse 1 rises at room temperature, when the temperature is greater than 30 ° C, the moisture on the surface of the material 12 begins to evaporate. When the control room humidity meter shows that the indoor relative humidity is ≥90%, turn on the fans 7.1, 7.2 and valves 13.1, 13.3, 13.5, 13.15, close other valves and fans, so that the high temperature and high humidity gas in the solar greenhouse enters the air condenser 2, The cooled high-temperature high-humidity gas and the condensed water are discharged into the water bath dust remover 9, and the heated normal-temperature air is sent to the solar greenhouse 1 dry article, and the drying wind speed is controlled at about 2 to 2.5 m/s;

1.5) When the humidity meter of the control room shows that the indoor relative humidity of the solar greenhouse is ≤40%, close all the fans and valves, so that the solar greenhouse is in a closed state, repeat 1.1) to 1.4), and continuously use solar energy to dry the items.

Strong cooling hot air drying process:

2.1) Turn on the fan 7.1 to extract the high-temperature and high-humidity gas in the solar greenhouse 1 above the air condenser 2, and turn on the fan 7.2 to pump the normal temperature air to cool the high-temperature and high-humidity gas, the cooled high-temperature high-humidity gas and the condensed water. Discharged into the water bath precipitator 9, the heated ambient air is sent to the solar greenhouse 1 dry goods, at this time, the solar greenhouse 1 is in a forced convection heating and drying state, the wind speed is controlled at about 2 m / s; at the same time, the fan 7.3 is turned on, and the hot blast stove 3 is activated. The heated flue gas is sent to the air heater 4, and at the same time, the fan 7.4 is turned on, and the normal temperature air is sent to the air heater 4. Normal temperature air is heated into high temperature and low humidity air in the air heater 4 (the temperature of the high temperature low humidity air can be determined according to the nature of the material 12), and the high temperature and low humidity air is sent to the dry material 12 in the solar greenhouse 1, and the high temperature and high humidity formed after drying The gas is sent to the air condenser 2 by the fan 7.1. At this time, the fans 7.1, 7.2, 7.3, 7.4 and the valves 13.1, 13.3, 13.7, 13.14, 13.5 are in the open state, and the other fans and valves are in the closed state;

2.2) After the high temperature and high humidity gas enters the air condenser 2, the cooled gas and the condensed water are sent to the outer row of the water bath dust remover 9;

2.3) When the hot blast stove 3 is operated, the temperature of the flue gas discharged from the air heater 4 is above 400 ° C, and the heat in the flue gas can be used for cold air drying. The flue gas discharged from the air heater 4 is sent to the flue gas lithium bromide refrigerator 5, and then the chilled water of 5-7 ° C generated by the flue gas lithium bromide refrigerator 5 is sent to the air cooler 8 by the water pump 6.1, and the cold air blower 8 is prepared 18~ The dry cold air at 25 ° C is sent to the solar greenhouse 1 in the lower part of Fig. 1, and the wind speed is controlled at 2 to 3 m/s. The material 12 in the solar greenhouse 1 requires a lower drying temperature. At this time, except for the valves 13.2, 13.4 and 13.5, the other fans and valves are in the open state;

2.4) After the cold air is in contact with the material 12, the humidity is increased, and the fan 7.6 sends the air with higher humidity to the dehydrator 10, and is discharged after being cooled and dehumidified.

The core of the invention lies in the preheating drying by means of solar energy, which not only saves energy but also ensures the quality of drying. Same At the same time, the introduction of hot air stove 3 as a heat source, with air heater 4 and flue gas bromide refrigerator 5 and other flue gas refrigeration devices, can be used for hot air and cold air drying at the same time, so that the flue gas energy is fully utilized, reflecting the energy Level use improves the efficiency of heat use and the economics of drying. Therefore, the scope of protection is not limited to the above embodiments, and any related products obtained by anyone in the enlightenment of the present invention vary in form and structure, as long as they are the same or similar technical solutions as the present invention. Within the protection of the present invention. It is apparent that those skilled in the art can make various modifications and variations to the present invention without departing from the scope and spirit of the invention. For example, the hot blast stove 3 is a heat source in the present invention due to its advantages in structure and use cost. First, but the use of other existing equipment such as boilers as a heat source can also achieve the technical solution of the present invention; similarly, other conventional flue gas refrigeration devices can be used instead of the flue gas lithium bromide refrigerator 5 in the embodiment; top surface and three The use of PC solar panel 1.1 on the sunny side is a preferred solution of the present invention, and it is also feasible to use tempered glass, plexiglass, and FRP lighting panels with similar properties; the top shape of the solar greenhouse 1 and the material of the energy storage wall 1.2 can also be based on the site. The situation is adjusted; the air condenser 2 is not limited to steel, and can be fabricated by other materials with good heat transfer and corrosion resistance; the pressure control in the solar greenhouse is controlled at 50,000 Pa, which is a combination of operability, technical effect and cost factor. After the choice, the pressure control has a good effect at 30,000 to 70,000 Pa; the cold air discharged from the air cooler 8 also serves as its Air source device, the present invention is not limited to a solar greenhouse 1 and the like. It is intended that the present invention cover the modifications and variations of the invention, and the scope of the invention.

Claims

A drying system combining hot air and cold air drying, characterized by comprising a solar greenhouse (1), an air condenser (2), a water bath dust remover (9), a heat source, an air heater (4), a flue gas refrigeration device , the air cooler (8), and the valves and fans installed on the pipes and pipes connecting the devices;

The solar greenhouse (1) is a sealed structure, the building structure is a frame structure, and the top surface and the three sun-facing surfaces are composed of PC sunlight board (1.1), tempered glass, plexiglass or FRP lighting board, and the non-receiving side is energy storage. Wall (1.2), the floor of the solar greenhouse (1) is a concrete perforated plate (1.3), and the concrete perforated plate (1.3) is placed above the ground, above which is used for placing the material to be dried (12) and for ventilation underneath;

The air condenser (2) has a cylindrical structure, and the air inlet and outlet are opened on the side of the cylinder for air in and out, and the upper and lower nozzles are respectively provided with a gas box (2.1), and the two gas boxes (2.1) pass through the air pipe. (2.2) beam communication, for accessing the gas to be cooled;

The heat source is connected to the air heater (4) for heating the gas introduced into the air heater (4) by using the flue gas;

The solar greenhouse (1) has an air inlet under the floor, an air outlet above the floor, an air inlet of the solar greenhouse (1), an air outlet of the air condenser (2), and an outlet of the air heater (4). The pipeline is connected, the air outlet of the solar greenhouse (1) is connected to the upper air box (2.1) of the air condenser (2), the lower air box (2.1) of the air condenser (2) and the water bath dust collector (9) Connected

The flue gas outlet of the air heater (4) is connected to the flue gas refrigeration device for preparing chilled water by using flue gas heat;

The water inlet and the water outlet of the flue gas refrigeration device are respectively connected with the water outlet and the water inlet of the air cooler (8) for cooling and dehumidifying the air passing through the air cooler (8).
The drying system combining hot air and cold air drying according to claim 1, characterized in that: the energy storage wall (1.2) of the solar greenhouse (1) is made of aerated concrete and rock wool insulation layer and is additionally stored with energy storage. The mortar is composed of a hollow brick masonry which is filled with a storage mortar material, and the phase change heat of the energy storage mixed mortar is not less than 60 kj/kg.
A drying system combining hot air and cold air drying according to claim 1 or 2, characterized in that the top surface of the solar greenhouse (1) is a single-sided large slope-shaped slope.
A drying system combining hot air and cold air drying according to claim 1 or 2, characterized in that It is that the indoor surface of the solar greenhouse (1) is coated with a far-infrared reflective coating.
A drying system combining hot air and cold air drying according to claim 1 or 2, wherein the air condenser (2) and the air tube (2.2) bundle therein are made of steel and the air pipe (2.2) The surface is coated with an anti-corrosive coating.
A drying system combining hot air and cold air drying according to claim 1, wherein the heat source is a hot air furnace (3).
A drying system combining hot air and cold air drying according to claim 1 or 2 or 6, wherein the flue gas refrigerating device is a flue gas lithium bromide refrigerator (5).
A drying system combining hot air and cold air drying according to claim 1 or 2, characterized in that the air outlet of the air cooler (8) is in communication with the air inlet of the other solar greenhouse (1).
A drying system combining hot air and cold air drying according to claim 1 or 2, wherein the solar greenhouse (1) is a micro-pressure chamber having a pressure of 30,000 to 70,000 Pa.
A drying system combining hot air and cold air drying according to claim 9, wherein the solar greenhouse (1) is a micro-pressure chamber having a pressure of 50,000 Pa.