Materials Selection for Bitumen with Heavy Naphthenic Acid in Canadian Oil Sands

摘要

Canada's oil sands contain one of the largest reserves of oil in the world. According to recent estimates, there are nearly 180 billion barrels of oil in the Canadian oil sands trapped in a complex mixture of sand, water and clay. More than 40 companies have been currently operating or developing oil sands facilities since the first production in 1967.Current oil production from the oils sands is approximately 1 million barrels per day with 3 million barrels per day forecast by 2015. The produced bitumen requires upgrading before it can be fed into conventional refineries due to undesirable octane value, sulfur contents, chloride contents, coke, other impurities, and heavy viscosity.The process of oil sands upgrading is similar with down stream refinery, but the corrosion environment in upgrading refinery is often more severe than in the refinery because of high chlorides, mineral contents, carbonic acid, heavy viscosity and fouling, higher naphthenic acid [NA-R(CH_2)nCOOH], and greater sulfur contents.Naphthenic acid corrosion (NAC) which is one of the most critical corrosion issues in up & downstream refinery plants was observed for the first time in 1920's in refinery distillation processes of Rumania, Azerbaizan (Baku), Venezuela, and California. As a first API report, the 11th annual meeting stated sources and mechanism of NAC in early 1930's. API has been developing the risk base standards, such as API RP580, 571, and Publication 581 which are based on the worst NAC damage in the world since 2000.Nevertheless not only the NAC phenomena and control in Canadian sands oil process are not much widely known but also there are still no engineering guidances for the Canadian sands oil in API standards.This paper will give NAC phenomina and materials selection guidance against NA environment in Canadian oil sands upgrading processes.