Case Study - Pernis Refinery

Challenge:

A large-scale refinery in Pernis, near Rotterdam in the Netherlands was experiencing problems with fouling resulting in diminished performance in the air compression equipment. Mexel was brought in on a full-scale trail to solve the declining production problem. The cooling water was a brackish mix drawn from the Rhine River and North Sea. The amount of fresh or seawater varied due to fluctuations with tide, river, wind, etc. Dissolved and suspended solids were also present in the water from this major seaport.

Treatment:

All compressor units employ a 2-stage compressor alongside four heat exchangers. Two heat exchangers, one oil and one regeneration cooler, operate in the 175°F to 200°F range. Two other heat exchangers, one an intermediate gas cooler and one a final gas cooler, operate in the 400°F to 500°F range. Mexel was daily dosed at 7 ppm for 15 minutes daily in the circulating water. The unit being tested operated continuously for 13 months before being taken offline for inspection. Prior to Mexel treatment, heat exchangers were taken apart and cleaned at least every six months due to accumulations of mussels and other biological growth, especially in the colder sections of water circuits. Severe corrosion and marcofouling deposits were often found in the tubes of the hottest areas and necessitated replacement of the first few bundles.

Results:

The tested unit was found to be free of fouling. With no gradual rise in outlet gas temperatures, no increase in water flow was needed to maintain the required discharge temperatures. All four heat exchangers were clear of corrosion and other deposits after inspection. The tested unit was returned for service without any needed cleaning and the site’s other air compressors units are now treated with Mexel.