How to Utilize DC Exhaust Heat in Oil Mill?

D.T.D.C (Desolventizer, Toaster, Dryer and Cooler) is a meal desolventizing equipment in edible oil extraction plant for removing solvent contained in spent meal from the extractor by water vapor in DT. In order to ensure better storage and transportation of meal, it is necessary to dry the meal in DC to safe moisture and to cool it to safe temperature, normally to 12~13% moisture and less than 40℃.

In the meal drying process, the moisture in the hot meal will vaporize with the hot air, and wet air with high moisture content will be formed. Generally, the moisture content is 13~17%, and the temperature is 75~85℃. This vapor contains considerable stench substances and dust. The dust can be removed by the cyclone. With large scale extraction plants, this exhaust hot air from DC tend to pose a serious air pollution problem and may have a serious impact on the surrounding environment.

In order to solve this problem created by DC exhaust vapor and achieve the goal of coordination between environmental protection and production, Myande developed patented technology to utilize this hot exhaust vapor from DC after deodorization (Patent No.CN201320760659.8, CN201420685756.X, and CN201520639876.0).

This technology includes the comprehensive treatment of DC and other wet and dusty vapor. Based on this patented technology, Myande has developed two process designs, namely the indirect heat utilization and scrubbing heat utilization, which have been successfully used in several production lines to the high satisfaction of the plant management.

The indirect heat exchange system adopts stainless steel plate heat exchanger in which hot air from cyclone outlet exchanges heat with the cool air from blower inlet directly. In general, the cool air temperature will be increased to more than 40℃, as shown in Figure 1-1.

Scrubbing heat exchange system uses water to spray the hot air from the cyclone outlet in order to form hot water, which after filtration, will be used to heat the cooling air from DC inlet. At the same time, it can be used to heat the air used for the drying section of oilseed pre-pressing plant, thereby reducing steam consumption, see Figure 1-2.