Effects of Silica Polymization on Apparent Viscosity of Geothermal Water - Fundamental Study on Precipitation of Silica Scale -

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This study discussed on (1) the rate of silica polymerization, (2) the relation between the apparent viscosity and the deposition to carbon steel and (3) the decrease of permeability caused by the precipitaion of silica. The conclusions are as follow:(1) The rate of decrease in soluble silica concentration is proportional to the surface area of polysilicic acid and the twice power of the oversatulated soluble silica concentration, when the experimental conditions are under pH8-9, temperature 30-50゜C, NaCl concentration 0 mol dm^<-3>, initial soluble silica conc. about 520ppm and total silica conc. about 570ppm.(2) As the apparent viscosity of solution increases, the quantity of silica deposition to carbon steel increases. Also as the precipitation is generated, the apparent viscosity of solution increaes rapidly. Then, the experiments conditions are; ph8-9, temp. 30゜C, NaCl conc. 0-1mol dmD1-3@>D1, initial soluble 250-1500ppm.(3) The effects of silica precipitation to the decrease of permeability depend on the particle diameter, when the experiments are carried out by using packed bed with glass beads. In the case of 0.3mm diameter beads, the permeability decreases generally. On the other hand, in the use of 1mm diameter beads, recovery of the permeability after the rapid decrease.