Life cycle assessment of milk powder spray drying system in China

Due to serious environmental impact from huge amount of energy and water resource consumption in industrial processes, the industries have been looking for new systems based on renewable energy. Performance of the directly-irradiated fluidized gas heater (50 mm-ID × 100 mm high) with silicone carbide particles has been determined for the application of exhaust steam reuse in the low- and medium temperature processes. The minimum fluidization velocity (Umf) of SiC is 0.0054 m/s, where the solar receiver was operated for keeping the fluidization state. The bed temperature shows a maximum value of about 200 °C around 0.013–0.021 m/s of gas velocity. It is considered that a high gas temperature is obtained in the vicinity of the minimum bubbling velocity where small bubbles are formed. The produced heat energy increases up to 18 W with increasing gas velocity. The optimum condition in this study is around 0.050 m/s. The energy efficiency was calculated to be 14%. A possible improvement of the gas heater has been proposed based on the experimental results.

Sung Won Kim

Papers

Development of a Fluidized Bed Gas Heater Using Solar Heat for Waste Steam Reuse in the Plant