CN101799236A - Heat pump carrier gas flow-through type continuous drying equipment - Google Patents

Abstract

The invention discloses a heat pump carrier gas through-flow continuous drying equipment, which is composed of a drying tower, a heat pump system and a circulation system. Through the circulation system, the drying tower and the heat pump system that continuously feed and discharge materials are coupled into a whole that can be operated continuously. The material is dried by the circulating carrier gas heated by the heat pump system during the continuous flow in and out of the high-pressure rotary valve at the top and bottom of the drying tower. . The invention uses a heat pump system to provide a heat source for the drying process, which effectively reduces energy consumption and improves the economical efficiency of equipment operation. During the operation of this equipment, the carrier gas can be cooled by the heat pump system, and the high-value volatile components contained in the dry material can be recovered, which increases the application range of the equipment.

Description

A heat pump carrier gas through-flow continuous drying equipment

technical field

The invention belongs to the field of chemical industry, and in particular relates to a continuous drying equipment of a heat pump carrier gas through-flow type suitable for granular or powdery materials.

Background technique

In chemical production, drying usually refers to heating wet solid materials with hot air, flue gas, microwave and infrared rays to vaporize and remove the moisture or solvent contained therein, which is a unit operation belonging to the heat and mass transfer process. Drying operation is widely used in various departments such as chemical industry, food, light industry, textile, coal, agricultural and forestry product processing and building materials. Drying operation requires a lot of energy consumption. Research by Italian scientists shows that the energy consumption of rice drying and processing accounts for 64% of the total energy consumption of rice production and processing. With the increasingly serious global energy and resource problems, more and more attention has been paid to the energy saving research of drying operation. Heat pump drying technology is a new type of drying technology developed under this background.

Compared with other drying technologies, heat pump drying technology has significant energy-saving characteristics. Another notable feature of heat pump drying technology is its low drying temperature and unique low-temperature dehumidification function. It can dry materials at a lower temperature and reduce the final moisture content of materials to an extremely low level. It is especially suitable for some Drying of heat sensitive products. The utility model with the patent number ZL200820220667.2 discloses a heat pump type vacuum continuous drying equipment. This invention uses the heat pump system for the continuous drying process of grain, which reduces energy consumption and realizes the continuous operation of the drying process, but the design is to pass the working medium of the heat pump into the coil in the drying tower through contact heat transfer Dry the material. This design requires the use of a large amount of heat pump working medium, a large amount of coils, and a complex structure, which is not conducive to equipment maintenance and repair. At the same time, it reduces the effective working volume of the dryer and increases the volume of the drying tower.

Contents of the invention

[Purpose of the invention] Drying is a unit operation that consumes a lot of energy. In order to reduce the energy consumption of drying, it is necessary to develop and utilize new drying technologies. Heat pump technology is a very potential energy-saving technology. The invention skillfully combines heat pump technology and drying process by circulating carrier gas, not only effectively utilizes the energy-saving advantages of heat pump technology, but also inherits the characteristics of traditional drying technology, so that the drying process can meet the requirements of energy saving, wide application range and continuous operation.

[Concept of the present invention] Traditional drying equipment generally includes box dryers, belt dryers, airflow dryers, fluidized bed dryers, drum dryers, spray dryers and drum dryers. Dryers suitable for drying granular materials include airflow dryers, rotary drum dryers, fluidized bed dryers and box dryers. Although the drying effect of these dryers is better, the energy consumption is generally high. The combination of heat pump technology and drying process may effectively reduce the energy consumption of drying, but how to combine heat pump and drying process is the decisive factor for the efficiency of the formed drying equipment. The invention combines the advantages of the heat pump technology, the air-lift distillation technology and the airflow drier, so that the drying process is continuous, volatile substances can be recovered, and energy saving and consumption reduction are simultaneously achieved.

[Technical scheme of the present invention] basic structure of the present invention is as accompanying drawing 1:

The material to be dried is lifted from the elevator 6 to the feed port 1 and enters the drying tower through the high-pressure rotary valve 3 for drying. The high-pressure rotary valve 3 is installed at the inlet and outlet of the drying tower 4. In order to maintain the airtightness of the drying tower 4, By connecting in series, two high-pressure rotary valves 3 can be installed at the inlet and outlet respectively, and the installed high-pressure rotary valves 3 can maintain an appropriate rotation speed to ensure the coordination of the feeding speed and the discharging speed. After the material enters the drying tower 4, it is controlled by the baffle plate 5 to carry out a z-shaped flow in the drying tower, flowing from the top of the tower to the bottom of the tower, and is transported from the heat pump condenser 9 to heat the carrier gas during the flow process. Heat to evaporate the moisture contained in the material, thereby drying the material. The carrier gas with increased humidity is drawn from the top of the drying tower 4 by the Roots blower 7 and sent to the heat pump evaporator 8 for cooling, and the moisture and other volatile components in the carrier gas are cooled in the heat pump evaporator 8 to obtain cooling liquid 12. Depending on the composition of the cooling liquid 12, the cooling liquid 12 can be dried as a by-product or discharged. The cooled carrier gas then enters the heat pump condenser 9 for heating, and then circulates into the bottom of the drying tower 4 for drying of materials. According to the heat sensitivity and water content of the material, the temperature of the carrier gas can be adjusted by adjusting the working parameters of the heat pump compressor 10 and the throttle valve 11, and the flow rate of the carrier gas can be adjusted by adjusting the Roots blower 7. Through these adjustments, it can be easily Good adaptability to different materials.

The present invention has the following characteristics and advantages:

1. The structure of the drying tower is simple, there are no mechanical moving parts inside, which increases the overall reliability of the equipment, and the continuity of the drying process is truly realized through the high-pressure rotary valve feeding and discharging in series;

2. Through the design of the baffle in the drying tower, the contact between the material and the carrier gas is more uniform during the flow process in the drying tower. At the same time, the design of the drying medium (carrier gas) flowing directly in the material to be dried makes the two The heat transfer coefficient is larger, which increases the heat transfer efficiency, and the temperature of the carrier gas can be adjusted freely within a large range, so that it can adapt to the drying of various materials;

3. Through the coupling of heat pump technology, gas stripping distillation technology and drying process, the drying process has achieved continuous, energy-saving and high-efficiency. The introduction of the concept of gas distillation makes the drying process also play a role in the recovery of high-priced volatile substances, further reducing the cost of drying operations. Operating costs, only electric energy is used in the drying process, no pollutants are released during the whole process, improving the economics of the process, with minimal impact on the environment.

Description of drawings

Fig. 1 Structural schematic diagram of heat pump continuous drying equipment, 1, feed inlet; 2, discharge outlet; 3, high-pressure rotary valve; 4, drying tower; 5, baffle; 6, hoist; , heat pump evaporator; 9, heat pump condenser; 10, heat pump compressor; 11, throttle valve; 12, coolant.

Detailed ways

The present invention will be further described below by embodiment.

Example 1

The equipment disclosed by the invention is used to dry distiller's grains. Distiller's grains are an important by-product of liquor production. According to statistics, the output of distiller's grains has reached 15 million tons. Faced with such a huge amount of resources, my country has conducted a lot of research on this, for example, using distiller's grains to cultivate edible fungi, extract compound amino acids and trace elements, extract phytic acid and calcium phytate, extract protein, and produce amylase or cellulase , using vinasse anaerobic fermentation to recover biogas, produce feed protein, and produce γ-aminobutyric acid, etc. Although there are so many methods, the utilization rate of distiller's grains is still not high at present. A limiting factor that limits the full utilization of distiller's grains resources is that the pH of freshly discarded grains is low, and the moisture content is high (above 60%), which is easy to spoil and deteriorate, which is not conducive to Preservation and long-distance transportation. Drying distiller's grains will have an important impact on the utilization of distiller's grains. The traditional drying methods mostly use flue gas for drying, and the thermal efficiency is low. In addition, distiller's grains also contain some valuable components, including aroma substances produced during the brewing process of liquor. The aroma component of the wine body fermented in the fermented grains is mainly ethyl caproate, but the traditional distillation method has a low yield of aroma substances. Taking the production of Luzhou-flavor koji wine as an example, the yield of ethyl caproate in distillation is It is less than 10%, so it will be very necessary to recycle these substances.

The distiller's grains with a water content of 60% are dried with a heat pump carrier gas flow-through continuous drying equipment with a volume of ^5m3 . The diameter of the drying tower used is 1m, the height is 6.5m, and 6 baffles are installed inside, and the installation angle is 30 °, equipped with SL80WD Roots blower (motor power 7.5kw), carrier gas flow rate of 15m ³ /min, equipped with a corresponding heat pump system, adjust the inlet temperature of carrier gas (carbon dioxide) to 80-85°C, and the cooling temperature to 4-6 °C, the drying rate of the material is 1 ton of wet distiller's grains/day, the power of the heat pump system is 10kW/h, and the water content of the outlet stream is 15%. During the drying process of the distiller's grains, the low-concentration alcohol and aroma substances in the distiller's grains are recovered at the same time. 1 ton of distiller's grains can recover 0.53 tons of distiller's grains.

Example 2

Drying of wheat is carried out with the equipment disclosed by the present invention. The wheat with water content of 17% is dried with a heat pump carrier gas flow-through continuous drying equipment with a volume of ^5m3 . The diameter of the drying tower used is 1.14m, the height is 5m, and 5 baffle plates are installed inside, and the installation angle is 35° °, equipped with SL80WD Roots blower (motor power 7.5kw), the carrier gas flow rate is 15m ³ /min, equipped with a corresponding heat pump system, adjust the inlet temperature of the carrier gas (air) to 47-50°C, and the cooling temperature to 4-6 °C, the drying rate of the material is 15 tons of wheat/day, the power of the heat pump system is 5kW/h, and the moisture content of the exported wheat is 12.5%.

Claims (7)

1. A heat pump carrier gas flow-through continuous drying equipment: it is formed by coupling a drying tower 4, a heat pump system 8, 9 and a carrier gas circulation system 7 connecting the two, and is installed on the top and bottom of the drying tower through a series of high-pressure rotating Valve 3, the material to be dried enters continuously from the top, is dried by the carrier gas heated by the heat pump system, and is continuously discharged from the bottom after drying, and the carrier gas used in the drying process is cooled and removed in the evaporation tower 8 of the heat pump system After the water enters the cooling tower 9 of the heat pump system, it is heated and then enters the drying tower 4 to circulate and work. 2. The heat pump carrier gas flow-through continuous drying equipment according to claim 1, characterized in that, the drying tower is columnar with a ratio of height to diameter of 5:1-20:1. 3. The heat pump carrier gas flow-through continuous drying equipment as claimed in claim 1, wherein baffles are set in the drying tower, the number of baffles is 3-15, and the baffles and drying The axis of the device is arranged at an angle of 30°-45°. 4. The heat pump carrier gas flow-through continuous drying equipment as claimed in claim 1, characterized in that, one or 2-3 high-pressure rotary valves are installed in series at the top and bottom of the dryer to keep the drying tower Tightness during drying. 5. The heat pump carrier gas through-flow continuous drying equipment according to claim 1, wherein the carrier gas is air, carbon dioxide, nitrogen or a combination of the above gases. 6. The heat pump carrier gas flow-through continuous drying equipment according to claim 1, characterized in that, the carrier gas circulation system is driven by a Roots blower. 7. The heat pump carrier gas through-flow continuous drying equipment according to claim 1, characterized in that the temperature of the carrier gas is 40°C-90°C.

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