Erosion Experimental System Design and Experimental Research of High Temperature Molten Salt
Abstract
The erosion behavior of two types of stainless steel in mixtures of sodium nitrate (NaNO3) and potassium nitrate (KNO3) is presented. The erosion resistance can be used to evaluate the lifetime of heat exchange tubes for solar thermal applications. A molten salt erosion experimental system was established for this purpose. Erosion tests were conducted for approximately 750 hours with type 304 and 321 stainless steel at 500 oC and 400 oC with different molten salt wash velocities, ranging from 1.09 m/s to 2.98 m/s. Erosion rates were determined by mass losses, and the results indicate that short-term erosion rates of the two types of stainless steel can be described in term of parabolic kinetics. The annual rates of metal loss were measured to be 10.8 to 18 μm/year for 304 stainless steel at 500 oC depending on the wash velocities. Metal loss for 321 stainless steel at 500 oC is about 7.68 to 10.92 μm/year. Based on these results, we confirm that the erosion resistance performance of 321 stainless steel is better than that of 304, which may be related to the titanium in 321 stainless steel.
Keywords
Erosion behavior, Molten salt, 321stainless steel, 304stainless steel