A Comprehensive Review on Fouling of Heat Transfer Units in Sugar Factory Ethanol Plant: Mechanisms and Mitigation Methods

Fouling in heat transfer units has a negative economic impact. Many scale-forming impurities are present in cane molasses generated by sugar cane production technology, including cations of aluminum (Al), calcium (Ca), iron (Fe), magnesium (Mg), potassium (K), sodium (Na), as well as anions of carbonates, sulfites, phosphates, sulfate, silicates, and chlorides. Ca cations, in particular, form insoluble complexes with many other chemical constituents, making them a scale-forming impurity. The accumulation of Ca ion on the heat exchanger's surface could increase heat transfer resistance and reduce its overall efficiency. This article reviews many types of heat-transmitting unit fouling and their successive fouling occurrences. Identifying the chemicals found in scale deposits helps to determine which cleaning products will effectively clean heat transfer units and which scale inhibitors will drastically lower scale formation rates. Furthermore, numerous unit operations and unit processes, such as molasses pre-treatment and pre-fermentation practice (inoculation of yeast), followed by fermentation practice, and product purification practice distillation, are used to limit deposit formation and boost ethanol production efficiency. Molasses pre-treatment and treatment such as chemical treatment, heat treatment, acid centrifugation, and mechanical treatment are critical in decreasing scale development during heat exchange operations.