Design and characterisation of a thin plate heat exchanger for fouling studies

Abstract A well-designed apparatus for fouling studies will allow different types of data to be collected simultaneously, reproducibly, under quantified flow, thermal and chemical conditions. The development and application of a thin plate heat exchanger for testing fouling in liquids and liquid solutions is reported. The device operates under constant temperature driving force, with heat transferred across a 1 mm thick, 12 mm wide and 150 mm long test section. The test liquid flows through a long rectangular duct with one heated wall section, and deposition can be monitored visually as well as quantified from heat transfer measurements. The thermal performance of the device is characterised in terms of hot and cold duties as well as local surface temperature measurements employing thermochromic liquid crystalline coatings. The data are compared with a coupled computational fluid dynamics and heat transfer simulation, which also estimates the rate of heat loss to ambient. These show reasonably good agreement. Application of the device to fouling studies is demonstrated using aqueous solutions of calcium sulphate. Uneven deposit distribution is observed, however, which complicates interpretation of the results.