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U.S. Department of Energy
Office of Scientific and Technical Information

Corrosion of fractionation towers in coal liquefaction plants

Technical Report ·
OSTI ID:6844713

Severe corrosion has been observed in the fractionating towers at the Wilsonville, Alabama Advanced Coal Liquefaction Facility and at the Ft. Lewis, Washington Pilot Plant. At Wilsonville, the high corrosion rate of carbon and of types 304 and 316 stainless steel occurred when the facility was processing coal with 0.15 to 0.39 wt % chloride. This corrosion was most severe in the 440 to 485/sup 0/F (225 to 250/sup 0/C) boiling range. The analysis of scale on coupons immersed in the tower showed a high concentration of water-soluble chloride. The analysis of organic compounds in the tower liquids revealed a large amount of acid fractions like phenols and cresols, and basic fractions like aniline. During lab experiments with liquids rich in chlorides and acid and basic fractions, a high corrosion rate was observed. Absence of one or more of these fractions resulted in negligible corrosion. Based on these observations, it is concluded that when water-soluble chlorides, basic nitrogen compounds (basic fractions), and phenols (acid fractions) are simultaneously present in the coal liquids, they exhibit a synergism that results in high corrosivity. In order to reduce the corrosion to acceptable levels, it is recommended that 904L and 317 stainless steel be used as the material of construction for the fractionation tower. It is also recommended that a chloride removal scheme be employed; the scheme would combine removal of chlorides before they reach the tower and a small side draw from the tower. 14 references, 11 figures, 8 tables.

Research Organization:
Air Products and Chemicals, Inc., Allentown, PA (USA)
DOE Contract Number:
AC05-78OR03054
OSTI ID:
6844713
Report Number(s):
DOE/OR/03054-52; ON: DE84013371
Country of Publication:
United States
Language:
English

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