Management of cleaning types and schedules in refinery heat exchangers

Abstract

Energy recovery and production in oil refinery pre-heat trains are greatly affected by fouling, the progressive build-up of unwanted material on the heat exchanger surfaces. Even when good design practices, operation or mitigation measures are in place, fouling cannot be completely eliminated in most situations. As a result, heat exchangers have to be periodically taken out of operation for cleaning. Traditional mechanical cleaning methods (e.g. hydro-blast) usually remove the whole deposit while chemical cleaning methods represent a less expensive option whose effectiveness depends on a number of factors (e.g. choice of chemicals, deposits composition and ageing, etc.). In this paper a detailed dynamic distributed model of shell and tube exchangers undergoing fouling has been used to simulate different cleaning schedules involving mechanical and chemical operations and assess their economic impact.