Drying pasty materials such as sludge from treatment plants, comprises subjecting sludge exiting from electrode hydration to laying operation that is moderated to preserve structure of sludge present in outlet of electro dehydration

摘要

The process comprises subjecting sludge exiting from electro dehydration (3) to laying operation (4) that is moderated to preserve a structure of the sludge present in an outlet of electro dehydration. A temperature of air in contact to the sludge in thermal drying step (5) is 75[deg] C. The laying operation comprises an operation of fragmentation of the sludge on a slab of installation of solar drying, and a transfer of fragmented sludge towards thermal drying in a solar drying installation, where the fragmentation step takes placed before heat drying step. The process comprises subjecting sludge exiting from electro dehydration (3) to laying operation (4) that is moderated to preserve a structure of the sludge present in an outlet of electro dehydration. A temperature of air in contact to the sludge in thermal drying step (5) is 75[deg] C. The laying operation comprises an operation of fragmentation of the sludge on a slab of installation of solar drying, and a transfer of fragmented sludge towards thermal drying in a solar drying installation, where the fragmentation step takes placed before heat drying step. The heat obtained from the water evaporated by electro dehydration is collected in a heat exchanger (6) for thermal drying. The steam heat is recovered with condensation of evaporated water. The dryness of sludge in outlet of the electro dehydration step is 30 mass.% while the dryness of sludge from the drying step is 60-95 mass.%. The thermal drying is performed under a partial vacuum to lower the evaporation temperature of the water. An independent claim is included for an installation for drying pasty materials.