温泉蒸気を用いたバイナリー発電所で生じた硫黄スケール

抄録

In the steam pipes at the outlet side of the evaporator of the binary power generation system using dry steam from Moto Hakone No. 38 well, the microstructures of the pipe with scaling and powdered scale from sampling the pipe were analyzed. The main component of adhered scale was soluble sulfur. No corrosion occurred on the stainless steel surface, and soluble sulfur adhered directly to the stainless steel surface. Therefore, soluble sulfur should be considered as a countermeasure against scale formation at binary power plants using steam. In addition, the saturation index (SI) of the soluble sulfur was calculated under the assumed operating conditions. As temperature decreases, SI of the soluble sulfur increased. In evaluating the effect of the H₂S/SO₂ ratio during condensation, it is recognized that it is difficult to completely prevent sulfur scaling because sulfur may precipitate when only a small amount of SO₂ is present in the geothermal steam. In the future, understanding the amount of sulfur scale formation under various conditions will lead to optimal system design.