Steam thermal cycle sludge drying method and system

The invention relates to a steam thermal cycle sludge drying method and system, wherein the method comprises the following steps of: (1) preheating sludge; (2) exchanging heat and drying the sludge from the step (1) by adopting steam as a heat source gas; (3) cooling and discharging the sludge from the step (2). The system comprises a preheating feeding device, a drying device, a technology cycle gas recycling device and a cooling and discharging device; the drying device comprises an evaporation chamber and a drying chamber which are sequentially connected; a sludge outlet of the preheating feeding device is connected with a sludge inlet of the drying device; a recycling steam outlet of the drying device is connected with a steam inlet of the technology cycle gas recycling device through a pipeline; the drying device is provided with a heat source gas inlet; and the heat source gas inlet of the drying device is connected with a steam outlet of the technology cycle gas recycling device through a heat source pipeline. According to the invention, energy source recycling measures are adopted, and the steam thermal cycle sludge drying method and system has the advantages of high evaporation efficiency, low cost, low energy consumption and the like.