Technical status and future development trend of drying equipment
Through the joint efforts of engineers and technicians in the dry industry, the drying equipment in China has made great progress in recent years. The structure and performance of the dryer have been significantly improved, and the quality has been continuously improved. Some models have been exported to foreign countries. In this paper, the technical progress of drying equipment in China is expounded in recent years, and the problems are also pointed out. Analyze the development of production technology in various industries in the future in China, put forward opinions on how drying equipment can meet production needs, and forecast the future trend of drying equipment, and provide reference for technology and equipment development. 1. Technical status of drying equipment In recent years, with the rapid development of industrial and agricultural production in China, the demand for drying equipment is increasing, and the overall level of drying equipment is also increasing. Conventional drying equipment can basically meet the needs of production, and some models are exported to foreign countries. These gratifying achievements are the result of long-term efforts of the majority of engineers and technicians. The progress of drying equipment is reflected in the following aspects: (1) Processing quality of drying equipment From the manufacturing process of drying equipment, the processing quality of drying equipment is restricted by the technical level and the application industry. There are many application industries for drying equipment, and the high quality of equipment is the pharmaceutical industry. Due to the particularity of the pharmaceutical industry, there are specific requirements for the material, structure and processing quality of the drying equipment used. Therefore, the processing quality of the equipment provided by the manufacturing industry is required to be high. Followed by the food industry, the food industry has strict hygiene requirements for drying equipment and drying systems, so the equipment structure and steel processing standards are higher. Some of the equipment in the chemical industry is relatively low in quality requirements. In all industries, the chemical industry, whether it is the amount of equipment or the type, is complicated. It should be said that the drying equipment of the chemical industry has strict requirements, but it is slightly lower than the above two industries. From the total quality of drying equipment in recent years, most of the steel plates have been polished, the welds are argon-arc welded (stainless steel), the welds are also treated, and some factories use automatic or semi-automatic welding for straight and circumferential welds. Welding ensures the quality of the equipment. Changzhou Daming Pharmaceutical Equipment Co., Ltd. and Changzhou Qile Machinery Equipment Co., Ltd. have good processing quality in the factories visited. (2) Structure of the dryer With the introduction of drying equipment in China and international technical exchanges, foreign drying equipment models are constantly affecting China. In recent years, China's new models and new structures are mainly manifested in the following categories: 1 Built-in heat pipe fluidized bed dryer: This type of dryer changes the heat of the fluidized bed in the past by the hot air. The internal heat transfer tube causes some heat to be transferred from the heat medium in the pipe. Greatly improved thermal efficiency. According to the data, the thermal efficiency of the traditional fluidized bed is 39.7%, while the heat pipe inside is 72.5%. With the same production done, the bed area was reduced from 72.5 m2 to 14.42 m2. Such equipment is available in Sulzer of Switzerland and Nara Machinery Manufacturing Co., Ltd., and the heat medium is generally steam, heat transfer oil, and the like. 2 Tube bundle dryer: The outer casing and transmission mode of the tube bundle dryer are very similar to those of the drum dryer, but 1 to 5 layers of tube bundles are arranged concentrically inside. The tube bundle passes through the entire length of the dryer, and is internally connected with water vapor or other heat medium for conduction and convection heat transfer. High thermal efficiency, total heat transfer efficiency of 80% to 90%, especially suitable for materials with a drying temperature below 150 °C. 3 Flash dryer: As a drying equipment introduced to China in 1989, it has the ability to process viscous filter cake materials, and can directly obtain powder materials. It is suitable for drying some mineral filter cakes and chemical intermediates with low viscosity. 4 paddle dryer: In 1990, the paddle dryer was first introduced into China by the Beijing Dyestuff Factory for the drying of indigo dyes. The paddle dryer is based on traditional heat transfer. The advantage of Zui is that it has high heat transfer efficiency and continuous production. 5- disc dryer: In the early 1980s, this technology was developed by the Shanghai Chemical Equipment Institute, but for various reasons, the equipment was not widely used. In recent years, many domestic dry enterprises have begun to develop this technology, which is basically mature to date, and there is also some progress in theoretical research on such models. 6Vibration fluidized bed dryer: This model increases the structure of controlling the running speed of materials. The distribution of hot air is more reasonable, and it can effectively prevent leakage. Compared with the ordinary vibrating fluidized bed, the area evaporation intensity is greatly improved. 7- slot type agitating dryer: It was developed earlier in Japan by the Kurimoto Iron Works. In the trough dryer, the structure of the original agitated material is composed of steam-forming pipes, which can stir the material and conduct heat. the goal of. 8 through-flow rotary dryer: It is installed in a rectangular parallelepiped box with a porous rotary cylinder. The cylinder body is provided with a plurality of copy boards in the circumferential direction, and the copy board also has small holes for processing materials with certain shapes. Similar to the rotary cylinder dryer, hot air passes through the barrel and the layer from the bottom of the cylinder. After being wetted, the dryer is discharged through the upper portion, and the dryer has the characteristics of a rotary cylinder dryer and a fluidized bed. 9 rotary air dryer: the earlier application of the German company Hearst, for the drying of PVC. The basic principle is that the main machine of the dryer consists of a jacketed cylinder. The hot air carries the material in the dryer to make a spiral ascending motion, the hot air flow and the material heat and mass transfer, and at the same time, the heat transfer and conduction by the jacket Radiation heat transfer, so the thermal efficiency is higher than the convection heat transfer air dryer. 2. Equipment scale As a unit equipment in production, the dryer meets the production requirements for high purpose. With the expansion of production scale in various industries, the scale of drying equipment has also been continuously expanded. At present, the diameter of the flash dryer equipment produced in China can reach 1.6m (there are not many application examples beyond this scale), and it works well. The heat transfer area of ​​the paddle dryer can reach 160m2, and it can pass through various heat transfer media. The large heat transfer area of ​​the disc dryer has reached 180m2. The processing capacity of the mechanical centrifugal spray dryer can reach 45t/h, and the electromechanical integrated atomizer also reaches the processing capacity of 5t/h, which better solves the mechanical problem of the atomizer. The diameter of the centrifugal spray dryer has been reached. 8 meters, total height of more than 50 meters, processing capacity of 4t / h. The rotary cylinder dryer can reach a diameter of 2.5 meters and a length of more than 30 meters. The belt dryer also has an area of ​​more than 140 square meters. 3. Equipment level The equipment level of the drying equipment mainly refers to the control level of the drying system, the equipment of the auxiliary equipment, the convenience of operation and the safety level. Throughout the equipment level of China's drying equipment, there has been considerable progress. This is especially true for large drying systems. Mainly in the following aspects: 1 control system is equipped. Automatic and semi-automatic control systems are widely used to reduce labor intensity and product quality. 2 application of computer technology. Most large-scale systems use computer technology to collect, process, and control system parameters, so that the operating conditions of the system are excellent. 3 humanized design. At the same time as the equipment design, consider the operator's habits and the ease of maintenance. 4 security design. There are safety alarms and danger elimination functions in the system, especially for the drying of flammable and explosive materials. 5 ancillary equipment. Auxiliary equipment in the system also tends to be reasonable, heating, feeding, gas-solid separation, product packaging equipment and host matching relationship to achieve zui optimization. 4. Experimental conditions The design of the dryer requires the relevant process parameters of the specific material. Many important parameters must be obtained through experiments. The design of the dryer is highly dependent on the experiment. Therefore, the experimental conditions are the key to accurately designing the dryer. Root Canal Measuring Table,Dental Root Canal Measuring,Dental Measuring Ruler,Dental Root Canal Equipment Foshan Ja Suo Medical Device Co., LTD , https://www.jasuodental.com