The color of the distiller's grains is affected by the color, proportion and drying temperature and drying duration of the raw materials, showing a pale yellow to dark brown. In addition to raw material factors, expert studies have shown that the deeper the color of the distiller's grains feed, the lower the amino acid utilization rate. Therefore, in order to ensure that the nutrients of the finished distiller's grains are not damaged, special attention should be paid to the drying temperature and drying time when drying with the distiller's dryer.
At present, the main drying methods are as follows. When selecting the white wine grain dryer, the user can understand the influence of different drying methods on the finished distiller's grains.
1. Direct heating and drying
The heat is directly contacted with the wet material, and the convection heat exchange. The heat loss of this technology is small, and the sludge solid content can be dried from 25% to 85% to 95%. Although the thermal efficiency is high, too high temperature will destroy the nutrients in the distiller's grains.
2. Indirect heating and drying
The heat circulates through the medium in a closed loop and is not in direct contact with the wet distiller's grains. The method has low drying efficiency and large heat loss, and cannot dry large-volume, high-humidity and high-viscosity materials, but has low nutrient damage due to low drying temperature.
The "low temperature and high air volume" high humidity and high viscosity distiller's grains dryer was upgraded and modified by Dingli Company on the basis of the original direct heating tumble dryer. The working principle is a drying process in which the drying efficiency is improved by appropriately increasing the wind speed and increasing the air volume within a set range and a low hot air temperature. After drying, the finished product has good color and no damage to nutrients. After the temperature is lowered, the generation of harmful gases such as dioxins can be effectively suppressed, and the difficulty of tail gas treatment in the later stage is reduced.