Research On Energy Saving And Emission Reduction Technology Of Continuous Grain Dryer

The purpose of this study is to promote the new type of energy-saving and emission reduction continuous dryer to development.Energy-saving dryer of high and low hot-air waste heat recovery,it has the advantages of energy saving,low temperature waste heat of exhaust steam recovery and utilization and hot blast furnace flue gas waste heat recovery and utilization,an integral energy-saving dryer.It is equipment with a hot-blast furnace of steel structure with air-cooled,heat efficiency reaches above 80%,obvious energy-saving effect,low drying cost,the flue gas of coal-fired hot-blast furnace for desulphurization and dust removal,the flue gas emissions to reach the requirements of environmental protection,provide a theoretical basis and example for the production of energy-saving and emission reduction of continuous dryer.The grain drier is an important means of production of grain storage,agriculture in developed countries such as in Europe,the United States and Japan,has become a common phenomenon of grain drying,grain drying mechanization level reached more than 95%,greatly guarantee the grain harvest yield,reduce the grain loss.In the grain production region in southern China,the harvest season hit in the rainy or humid coastal zone temperature,the grain is not timely drying or sun-cure,after 10 hours will have a fever,mildew and so on;in the northern grain producing areas,the autumn harvest of paddy and corn,when it is high moisture,without mechanical drying,the grain is very difficult to achieve safe water to storage in the autumn and winter,it cannot be put into the market to sell,visibly grain drying equipment is a very important link.At present,China’s continuous grain dryer market,the driers of 99% are the type of traditional exhaust emissions without exhaust steam recovery and utilization.The flue gas of a coal-fired hot-blast furnace is also a type of direct discharge without waste heat recovery.Therefore,the heat utilization rate of the dryer is low,the heat exchange efficiency of the hot-blast furnace is low,the heat consumption is high,the environmental pollution is big,and the cost of drying is high and so on.The recovery of grain drying waste heat is divided into the following: the recovery of the exhaust steam of the dryer(tail steam)and the recovery and utilization of the waste heat of the flue gas.When drying waste heat recovery,drying corn energy-saving effect is better than dry paddy.because drying corn has high hot-air temperature and high exhaust gas temperature,so recycling energy-saving effect is more obviously.From the test data,the temperature of the low temperature exhaust steam in dry paddy is 23-30℃,when winter temperatures for-10 ℃,the temperature rise of 33-40 ℃.Dry corn of low temperature exhaust steam recovery temperature of 35 to 40 ℃,the temperature rise of 45 to 50 ℃.The exhaust air volume of the dryer is calculated by 50000m3/h,which is equivalent to 500000 kcal/h of heat,equivalent to 500,000 Kcal/h,equivalent to about 100 kg of coal consumption,and nearly 160 kg of rice husk.Dry paddy from the flue gas temperature is 70-95 ℃ and the dry corn is 90-115 ℃.If we can recycle the low temperature exhaust steam and the waste heat of the flue gas,it can save energy and protect the environment.Therefore,the value of the exhaust steam recovery and the recovery and utilization of the waste heat of the hot-blast furnace is very important,and the development potential is huge.