What’s the fuel of the grain dryer?

What’s the fuel of the grain dryer?

The machine uses coal and straw as fuel, refrain the grain from pollution with small investments, and full automatic operation, which is suitable for the big or middle farm. The abandoned rice husk, firewood, straw, all of these can be used as the fuel materials, which save the expenses for coal or fuel gas , clean hot air for drying material without any pollution.