Premium
Corrosion of alloys in tall oil distillation service
Author(s) -
Templeton Harold C.
Publication year - 1970
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02640408
Subject(s) - molybdenum , corrosion , metallurgy , alloy , materials science , chromium , distillation , tall oil , resin acid , chemical composition , streams , chemistry , composite material , computer network , organic chemistry , computer science
Plant corrosion tests of various metals and alloys in tall oil distillation streams present the effect of alloy composition on corrosion rate. Stream temperature, alloy composition and stream composition are correlated so as to provide a useful guide to material selection for tall oil distillation plants. Alloys exposed to corrosion test were iron or nickel base with chromium plus varying amounts of molybdenum. Molybdenum is the most important alloy addition in reducing the rate of corrosion attack, with corrosion attack at a very low rate, <.1 mil per year, at the 6% molybdenum level in the most aggressive stream tested, i.e., 85% fatty acids at 518F. The presence of chromium does not appear to be essential to obtaining good corrosion resistance to the more corrosive conditions. Corrosion rates increase with increasing temperature. The streams classed as high in fatty acids are much more corrosive than those which are classed as high in rosin acids. Vapor phase streams are more corrosive than liquid phase streams. Corrosion attack is normally from pitting. Most of the more corrosive conditions can be handled with an alloy containing 3% to 4% molybdenum (AISI Type 317), but some process conditions require higher molybdenum contents in order to obtain acceptable corrosion rates. Less corrosive streams can be handled with an alloy containing less than 3% molybdenum (AISI Type 316).