Superheated steam drying method for sludge and drying equipment

The present invention relates to a sludge drying method, said method utilizes the sensible heat and latent heat of dried tail gas recovered by heat exchanger, and makes it exchange with water and heats it to obtain superheated steam, then makes the superheated steam by fed into a closed direct drying machine to make heat exchange with wet sludge being in said drying machine to obtain the dried sludge. Then said method can make the dried sludge and dried tail gas implement gas-solid separation, so that the dried sludge can be collected. Said drying equipment includes pipe-shell type heat exchanger, heater, closed direct drying machine and gas-solid separator, etc.