Abstract: A process for determining if intermittent water injection is the best way to remove deposits such as salts from refinery process streams. A water vapor pressure, P1, at stream conditions and a water vapor pressure, Ps, at saturation conditions in the stream, are used to calculate a ratio P1/Ps. If the ratio is less than 0.1 intermittent water washing is preferred. An optimized intermittent injection procedure, frequency, duration, and constraints, is disclosed. Chemical speciation calculations ensure that all accumulated salts are removed, and that an aqueous phase forms downstream of the water injection point having a salt concentration within acceptable limits.

Abstract: A continuous water washing process for removing salts from refinery process streams is disclosed. The salt and salt precursor content of a process stream is determined, and iterative calculations made to ensure an aqueous phase forms downstream of the water injection point with a salt and ion concentration within acceptable limits. Preferably chemical speciation calculations are used to check for corrosive, transient aqueous phases intermediate the point of water injection and the process outlet.

Abstract: A method for inhibiting corrosion of carbon steel in contact with a mixture of hydrofluoric acid and tetrahydrothiophene-1,1-dioxide comprising raising the electrical potential of said structure such that the electrical potential of said structure is positive with respect to said solution containing hydrofluoric acid and tetrahydrothiophene-1,1-dioxide.

Abstract: The present invention provides a method for inhibiting corrosion of carbon steel in contact with a mixture of hydrofluoric acid and tetrahydrothiophene-1,1-dioxide comprising adding a corrosion inhibiting amount of an alkali metal halide to said mixture of hydrofluoric acid and tetrahydrothiophene-1,1-dioxide.