Abstract
A study of the marine biofouling characteristics for titanium tubed heat exchangers has been carried out using a purpose designed test rig that enabled an accurate simulation of expected service conditions. Test rigs were constructed as self-contained remote controllable units that could be moved from site to site enabling fouling data to be obtained for different seawater environments. The quantification of fouling was performed using a combination of thermal resistance measurements, biofilm sample analyses and differential pressure measurements and data were obtained giving real-time fouling results for test periods of up to 90 days.
Once fouling behaviour had been characterised, tests were performed to investigate the efficacy of a number of chemical treatments by operating two rigs in parallel enabling the effects of chemical treatments to be directly compared to the fouling response on an untreated system.
Fouling behaviour was seen to be dependent upon seawater temperature, tube wall heat transfer conditions, seawater flow velocity and time of year as well as site location. Suitable chemical treatment programmes to control biofouling by periodic biocide injection were identified. The results allowed the definition of heat exchanger operating parameters for in-service units that seek to minimise biofilm growth.
