15 Refining, Engineering Companies Launch 'Sour Water' Study

Fifteen major refiners and engineering service companies have launched an industry-wide study to determine causes and solutions to refinery sour water corrosion. Sour water is ammonium bisulfide, a corrosive product from sulfur removal in refineries that has cost an estimated $50 million per incident in lost production and damages to several U.S. refineries over the past five to 10 years.

The program is headed by InterCorr International, Inc., an international corrosion solutions provider, in association with Equilon, a refinery operation owned by Shell and Texaco. The study and resulting data should revolutionize refinery sour water system design and unit operations and save operators millions of dollars.

"Refinery sour water systems now contain significantly higher levels of corrosion-causing ammonium bisulfide because of new environmental regulations," says Dr. Russell Kane, president of InterCorr. "Additionally, increased refinery unit throughput, unit upgrading and construction of new units all support the industry-wide need for this joint program."

Sour water program participants will benefit by minimizing major plant incidents, some of which have cost refiners up to $50 million per incident. Kane describes this program data and software as the cheapest insurance policy available.

Representatives from sponsor companies say that in the short time since the study began in March 2000, they have already recaptured their participation fee for this program in only a single application of the data.

The Sour Water Study - An Improvement Model

Various individuals and companies have conducted qualitative studies about alkaline sour water (ammonium bisulfide) corrosion in petroleum refineries in the past 25 years. Sour water systems are commonly found in refinery hydrocracker and hydrotreater applications and specifically relate to reactor effluent air cooler systems.

Yet, precise, quantitative information is needed for definitive unit design and operational guidelines on ammonia bisulfide corrosion for a variety of materials and service conditions.

"Our goal is to improve the prediction of ammonium bisulfide corrosion for use in selecting materials, controlling process unit operation and assessing chemical treatments," Kane said.

The two-year joint industry sponsored program will provide corrosion data in ammonium bisulfide environments that closely simulate conditions found in refinery sour water systems. A proprietary laboratory flow loop simulates sour water service conditions, focusing on the effects of velocity on corrosion and the performance of commonly used alloys. This information will be used to develop a computer model and predictive software tools that can be used to handle important, real-time refinery design and operational problems.