Under the pressure of environmental protection, how to solve the heat source problem of grain dryer?

In recent years, we have made initial achievements in environmental protection, especially in the treatment and prevention of industrial pollution. But at the same time, the impact on some industries is inevitable. Taking the grain dryer industry as an example, the heat source part is an important part of the grain dryer, and the heat source of the traditional grain dryer is mainly coal. With the implementation of the "coal ban order", grain dryers have to find new heat sources to replace the more seriously polluted coal, which puts forward a new subject for the national grain dryer production enterprises. For a long time, the grain industry is a low value-added industry. The development of the industry has always been in the state of "small profits and high sales, winning by quantity". As a traditional energy, coal is always the first choice of heat source for grain dryer because of its low price and easy access. However, under the pressure of national environmental protection policy, manufacturers have to develop new alternative energy schemes to ensure the normal use of grain dryer on the premise of meeting environmental protection emissions. At present, the main domestic alternatives are: natural gas, air energy heat pump, biomass particles, steam and other ways. Next, the successful experience of Zhengzhou WANGU Machinery Co., Ltd. in focusing on grain dryer for more than 20 years will introduce different energy sources.

Natural gas is a kind of clean energy. When fully burned, it mainly produces non-toxic carbon dioxide and water. In addition, it produces a very small amount of sulfur dioxide and nitrogen oxides. Because the content is very low, the impact on the environment is very small, which can be ignored. Therefore, the combustion gas of natural gas can be discharged directly without treatment. Therefore, the gas stove is more and more used in the grain drying industry. Users usually use fixed natural gas pipelines or natural gas transport vehicles and other non fixed ways to supply natural gas.

The steam heat exchanger is a kind of heat exchange equipment that uses the heat released by steam during condensation to heat the normal temperature air. It has the advantages of cleanness, cleanness, easy control of air temperature and easy operation. After being heated, the normal temperature air can be directly used as the drying medium of grain dryer. This method is generally only suitable for the occasion where there are large industrial steam resources near the grain dryer plant area, especially for the grain dryer built by some large grain deep processing enterprises, because the plant area is usually equipped with large-scale steam boilers, and there are surplus industrial steam available for use. At present, Wangu in Zhengzhou has successfully built dozens of steam grain dryers with a daily output of 1000 tons in Northeast, northwest, Henan and other provinces.


Biomass granular fuel is a kind of granular new energy fuel produced by processing straw, rice husk, firewood, peanut husk, corncob, oil tea husk, cottonseed husk, etc. Due to the lack of sulfur and phosphorus in biomass pellet fuel, no sulfur and phosphorus oxides will be produced during combustion, which will not lead to acid rain, and will cause less environmental pollution. There is very little ash after combustion of biomass pellet fuel, which can reduce the site for stacking slag. Moreover, the ash after combustion of biomass pellet fuel is high-quality organic potassium fertilizer, which can be recycled for profit. Generally, biomass particles have the characteristics of small bulk density, low calorific value and more fine dust after combustion. Therefore, it is necessary to optimize the furnace structure and tail gas dedusting of the hot blast furnace to meet the requirements of grain dryer heating and environmental dust emission standards.


Air energy heat pump is a kind of drying form which uses electricity as energy, absorbs and transforms the energy in the air as heat energy. With the advantages of clean and pollution-free, air energy heat pump technology has been gradually applied in the field of grain dryer in recent years. However, due to the limitations of the working principle of heat pump technology, at present, the technology is mostly used in small grain dryer equipment, and limited by the region in use, often used in warm areas in the south, and mostly used as the heat source of low-temperature rice drying.