The current situation of grain drying equipment in China and its development suggestions (1)
March 08 14:22:48, 2021
China is the world's largest country in food production and consumption. The total annual grain output is about 500 million tons. According to statistics, China's food loss in threshing, drying, storage, transportation and other processes is as high as 15%, far exceeding the 5% standard set by the UN Food and Agriculture Organization. Among these losses, each year, due to the humid climate, the moisture in the wet valley is too late to dry or it does not reach safe moisture. The loss of grain caused by mildew, germination and other losses is up to 5%. If the annual output is 500 million tons of grain, it is equivalent to 25 million tons of grain. If one person eats 1 pound of grain per person per day, the amount of 6.8 million people can be used each year. This figure is amazing. Therefore, the development of grain drying mechanization technology, changing the passive situation of the traditional rely on heaven to eat, so that the food loss reached to the lowest point, in this sense, the modernization of grain drying is more important than the field of agricultural mechanization, but also high yield The important guarantee conditions for the bumper harvest. I. Overview of the Development of Grain Drying Mechanization in China The development of grain drying machinery in China began with the imitation of dryers from Japan, the Soviet Union, and other foreign countries. Because of its complex structure, high consumption of steel, and high cost, it is not suitable for the rural economic and institutional conditions at that time. It is only used in large-scale farms and grain stores. In the 1970s, Guangdong Provincial Institute of Agricultural Machinery and other scientific research units began to develop small and medium-sized drying models suitable for China. The Guangdong Provincial Institute of Agricultural Machinery successfully developed a 5H-0.5 type stacking dryer with direct heating; the Shandong Institute of Agricultural Machinery developed an indirect-heated 5HJ-0.5 type simple grain dryer and more than 10 varieties, most of which are suitable for farm production. Company and rural production team use. After the 1980s, China's rural economic system began to undergo reforms, and most of the dry machines developed were developed in the direction of multi-purpose and miniaturization. In 1981, the Ministry of Agriculture, Nanjing Agricultural Machinery, organized a comparative test of 13 models of grain drying equipment in the north of the country, initially recommending a number of models. During this period, research on dry heat sources closely related to drying machinery has also made progress. Successively, hot gas generators, low calorific value gasifiers, rice husk gas generators, solid fuel gas generators, and tubeless hot blast stoves have been successfully developed. , liquefied gas hot stoves and solar drying devices. Since the 1990s, with the in-depth development of rural reforms, China's rural economy and agricultural productivity have developed rapidly, and there have been new developments in professional and intensive scale management. In particular, the large-scale grain warehouses and the seed and grain production bases of state-owned agricultural reclamation systems gradually equiped with complete sets of grain drying equipment, and together with warehousing, processing, and other facilities, became the main application representatives of grain drying machinery in China. At the same time there have also been specialization plants for drying equipment such as Sichuan Santai Drying Machinery Plant, Tieling Jinggong Machinery Plant of Liaoning Province and Heilongjiang Hongxinglong Machinery Plant. China Agricultural Engineering Research and Design Institute and Sichuan Agricultural Machinery Research Institute have emerged. Some achievements have been made by China Agricultural University and some agricultural research institutes and colleges in Heilongjiang and Liaoning. Since 1996, Taiwan's wholly-owned company Shanghai Sanjiu Machinery Co., Ltd. has produced a circulation type low-temperature dryer, and Japan's sole funded agricultural machinery (Wuxi) Co., Ltd. has also sold its seed-specific dryers and general-purpose dryers into the Chinese market and has driven Development of Drying Mechanization Technology in Southern Rice Production Area . Although these dryers have high prices, due to their good performance, reliability, high degree of automation, and thoughtful after-sales services, these dryers are still popular with users and have a promising market outlook. At present, the amount of such dryers in Jiangsu, Zhejiang, and Guangdong has reached about 1,000 units. In short, the development of grain drying technology gradually makes the drying machinery mature and perfect, at the same time, it also accelerates the pace of agricultural modernization, and promotes the development of productivity and scientific and technological progress. II. Introduction of Grain Drying Technology and Equipment According to the drying method and classification, the grain drying machinery can be divided into many types, and there are various names for the name. For example, according to the structure of grain dryer, it can be divided into: tower dryer, round Tumble dryers, fluidized bed dryers, pillar dryers, small mobile dryers, and more. Here are some representative models: 1. Low-temperature circulating grain dryer The low-temperature circulating grain dryer is the most common type of rice production area. The circulation dryer consists of three parts: a heating device, a grain automatic control device and a host machine. The main part of the structure of the mainframe includes drying ovens, regular grain-feeding agencies, conveying augers, lifting devices, unloading devices, suction fans, grain cleaning agencies, and transmission agencies. At present, Fuzhou Sanfafa Drying Equipment Co., Ltd., and Shanghai Sanjiu Machinery Co., Ltd., and Gold Agricultural Machinery (Wuxi) Co., Ltd. all produce this type of dryer. The 5HSC low-temperature circulating grain dryer developed and produced by Fuzhou Sanfafa Drying Equipment Co., Ltd. is a series of products that can dry grains such as rice, wheat, corn, sorghum, beans, and seeds. Its main features are: (1) low temperature and large air volume, thin grain layer drying, good drying quality, does not affect the germination rate; (2) can set the drying temperature, operating time and automatic control of the work process; (3) small footprint, No need to add auxiliary equipment, simple operation, and no fault alarm system; (4) Shorter heating time, slower SO time, stable drying temperature, uniform drying, and low heat consumption. This series of products are 15 type, 30 type, 45 type, 60 type, etc., can be selected according to need. The NHWPRO-60-72 circulating grain dryer manufactured by Shanghai Sanjiu Machinery Co., Ltd. can be used to dry seeds of crops such as rice, wheat, corn, sorghum and soybeans. It is one of the recommended models of the Ministry of Agriculture. The machine is characterized by: fast drying speed, double nozzle double throttle proportional burner, high thermal efficiency; using low-temperature and high-volume exhaust fan, baking cool grain, good quality; using computer to automatically monitor the moisture content, ensure drying The moisture requirements; the use of forced dispersion device, the uniformity of drying is good; using a multi-layer automatic operation monitoring system, the operation is simple and easy. 2. Tower-type net column dryer This model is commonly used in northern China's farm taste grain warehouse, commonly used to dry wheat and corn. The machine is equipped with a grain diverting device to exchange the position of the outer layer of the grain to achieve even heating of the grain. The unevenness of drying can be reduced to 1%. This type of dryer has an exhaust gas recovery device and can increase the thermal efficiency by about 30%. This type of dryer has a simple structure, reliable operation, and low processing and manufacturing costs, and is suitable for use in the large grain departments and the agricultural reclamation systems in the Northeast and North China. The current production of such large-scale dryer companies include Liaoning Tieling Seiko (Group) Co., Ltd. 3. Cylindrical recirculating grain dryer The drum recirculating mobile dryer has a simple structure, easy operation and can be moved. With tractors, not only can it be towed, but it can also transmit various working components. It has the following characteristics: (1) High productivity and fast drying speed. A dryer with a diameter of 2.4 meters, a height of 5 meters and a weight of 1500 kilograms can bake 2 tons of corn per hour (5% of precipitation). (2) The circulation speed of grain is fast. A cycle is completed every 10-15 minutes. After 20 cycles, precipitation can be more than 20%, and the drying is even and the mixture is good. (3) The dryer is designed for internal and external cylinder type, compact machine structure, small footprint, uniform distribution of hot air, consistent heating of food, and easy manufacturing. (4) Drying and slowing of the suing are carried out at the same time. The grain after high-temperature drying is sent to the upper cone with a vertical screw, which is used for a short period of time to slow the release of moisture inside the grain, conforms to the law of grain drying, and helps ensure food quality. (5) The machine uses a short drying section and high-speed circulation of grain instead of the slow flow of the tower, and the height of the fuselage is greatly reduced. In addition, the huge hoisting machine is eliminated due to the internal circulation of the grain. Therefore, under the same productivity and precipitation amplitude conditions, the machine is light in weight and small in size, which greatly saves steel. (6) Grain is always in a state of constant mixing and flowing, so it is evenly dried and the water evaporates quickly. (7) Drying is not affected by the moisture of the raw grain, and when the moisture is high, it is recycled for some time. (8) It does not require the installation of a dryer and costs the construction cost. At present, China's Guangdong Nanhai Machinery Plant and China Agricultural University complete sets of equipment are producing this dryer.