抄録
Most all of the thermal power plants in Japan are located on the shore and use seawater for cooling the turbine steam. The discharge of heated seawater should be restricted not to affect on the coastal ecosystem, and in addition, the seasonal variation of temperature of intake seawater is recognized as the significant factor of the power generating efficiency. One of the authors et al proposed a new cooling water system so as to avoid such problems, that is, the cooling water would be contained in a closed circuit pipe system and circulated between cold regions of the deep water and the condenser for turbine steam cooling. Fouling on surface of the heat exchanger may cause the degradation of heat exchanging performance. It is known that there is a quite small chance in the dark and clean deep sea water to produce the fouling, but we have not so many knowledge in case that the temperature is high at the circumstances in deep water. herefore,the effect of temperature on the fouling on the heat transfer surface is experimentally investigated in this study. A slender titanium pipe is immersed in the actual deep sea water btained with the deep water intake facilities in Ohshima Island, off the Izu Peninsula, and held in a container keeping 10 degC in temperature and darkness without light. Heated water at 80 degC is continuously put into the pipe and the decline of temperature along the pipe and the situations of the surface of pipe are observed for 30 days. As a result, bio-fouling, a thin bacteria film is observed on the heat transfer surface when the temperature is higher than about 40 degC.
