Indirect heating type dryer

Abstract

The invention provides an indirect heating type dryer which can realize volume reduction of a dried object with drying processing, the high filling rate of a dried object and the uniformity of a dried objected in a housing. The indirect heating type dryer indirectly heat the dried object in the housing for drying process by circulating a heating medium in a rotation shaft (4) and stirring wings (20), wherein the stirring wings (20) are of a wedge shape. Each stirring wing has a front side (S1) facing the housing, a first wing surface (20a) and a second wing surface (20b), wherein the first wing surface (20a) gradually inclines to the front side (S1) from a front end part (20c) of a front side of the rotation shaft (4) in a rotation direction (M) to a rear end part (20d) of a rear side toward the rotation direction (M).

Description

technical field [0001] The present invention relates to an indirect heating drying device for drying (reducing water content) various biological substances, sewage sludge, food waste and other water-containing objects to be dried. Background technique [0002] In the past, various types of biomass treated as waste have been recycled and effectively utilized, such as direct combustion of biomass to generate electricity using its heat energy, or production of biomass fuels such as methanol by gasifying and thermally decomposing biomass , carbide, etc. When the biomass is directly burned or recycled by gasification and thermal decomposition as described above, it is necessary to perform a pretreatment of drying the biomass to a predetermined water content or lower using a drying device. In addition, wastes such as sewage sludge, factory wastewater sludge, food waste / kitchen waste, fecal sludge, livestock excrement, and plant juice residue (water-containing state to be dried) s...

AI Technical Summary

Problems solved by technology

[0019] However, even when the baffle 11 is provided in this way, it is impossible to maintain a high filling rate uniformly from the front side S1 to the rear side S3, and the filling rate of the middle part S2 of the housing 1 becomes low, and the middle part The heat conduction surface of shell 1 or rotating shaft 4 and stirring wing 5 of S2 will be exposed

Therefore, along with the drying process of the object to be dried P, a useless space will still be generated in the middle part S2 in the casing 1, and useless heat dissipation will be generated from the exposed stirring blade 5, the rotating shaft 4, and the heat conduction surface in the casing 1, thereby Large heat loss, resulting in reduced drying efficiency

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