The heat exchangers were typically cleaned of their asphaltene build-up by removing the bundle and performing high pressure water blasting, taking up to 21 days per exchanger bank. Chemical cleaning had been tried repeatedly with no previous success.
The exchangers were cleaned using a 20% solution of FQE Solvent-H in a cutter stock, which was circulated on-line for 36 hours at 93°C (200°F). This process took a total of 5 days.
Upon completion of the chemical clean, the exchangers were brought back on-line at full rates with better temperature differentials than previously seen post high pressure water blasting. This successful chemical clean saved the refinery over $140,000 in maintenance costs and an additional 16 days in production time resulting in over $1,000,000 in additional revenue.