Abstract

Corrosion monitoring of austenitic stainless steels was performed in a biodiesel plant by using corrosion coupons due to the generalized corrosion observed in stainless steel. Corrosion resistance of AISI 304L, AISI 316L, AISI 317L and AISI 904L stainless steels was evaluated downstream of the hydrochloric acid insertion site in the biodiesel and glycerin streams, between static mixer and decanter (biodiesel circuit point 1) and between static mixer and a heat exchange (in glycerin circuit point 2). AISI 317L presented a good corrosion resistance at monitoring point number 1. At monitoring point 2, AISI 317L steel performed better than AISI 904L. AISI 317L was selected as pipe material to be used downstream of the insertion point of the hydrochloric acid solution into the biodiesel and glycerin stream.

Keywords: Corrosion monitoring; Corrosion coupons; AISI 316L steel; AISI 317L steel; Biodiesel plant