First, the drum dryer has restrictions on raw materials. The raw materials can be alfalfa, distiller's grains, straw, sawdust, marigold, shavings, ginkgo leaves, Chinese herbal medicines, brewer's grains, distiller's grains, potato starch residue, cassava residue, barley malt, melon seeds, bagasse, hawthorn, rapeseed cakes, vegetables and the like.

Second, drum dryers have restrictions on drying water. If the moisture content of raw materials is 80-90% before drying and 20-30% after drying, if the moisture content of raw materials before drying is about 40%, the moisture content after drying is about 10%. Some customers think that the drum dryer can dry 100% raw materials regardless of the water content. This idea is wrong. The drying effect is different with different water content, but if you want to dry the raw materials with high water content to the best, you can dry them twice.