#fouling

Fouling

Fouling can be defined as "the settlement, and sometimes the growth, of undesired materials on solid surfaces in a way that reduces the efficiency of the affected part." Though it rarely leads to catastrophic failure of materials, fouling nevertheless impacts a part's function, leading to a failure of its intended purpose. Like corrosion, fouling has considerable economic impact. There are numerous types of fouling, including biofouling (accumulation of living organisms), precipitation fouling (accumulation of crystals precipitating from solution), and particulate fouling (accumulation of particulates), among others.

Though similar, with overlap in their definitions, fouling and corrosion are not necessarily the same thing. (Though corrosion fouling is one type of fouling where the corrosion deposits build up, and fouling corrosion is another thing entirely, where corrosion is caused by fouling.) Corrosion is caused in-situ, as a result of reactions with the material/part. Fouling is caused by build up of ex-situ material, i.e., material that is not a component of the part that is being fouled.

The effect of fouling on heat exchanges is of particular interest to the industries involved, as is membrane fouling.

Getting dirty to clean up the chemical industry's environmental impact

The global chemical industry is a major fossil fuel consumer and climate change contributor; however, new Curtin University research has identified how the sector could clean up its green credentials by getting dirty. The article, "Insulator-on-Conductor Fouling Amplifies Aqueous Electrolysis Rates," was published in the Journal of the American Chemical Society. Most chemical reactions involving electricity and organic materials can't be done efficiently using water because the organic materials don't dissolve well, forcing industry to use fossil fuels to provide heat rather than electricity or use alternative substances to water, which add environmental and safety risks. However, a team of researchers led by Associate Professor Simone Ciampi, from Curtin's School of Molecular and Life Sciences, has found chemical reactions in water can be dramatically sped up by adding a water-resistant material to an electrode—a process known as "fouling."

Hot water tanks, washing machines, kettles: limescale forms in every domestic appliance that comes into contact with (hot) water -- especially in areas where the water is hard, meaning high in calcium. Often the only thing that helps is to use vinegar or a special descaler to dissolve the rock-hard deposits and restore the appliance's functionality. This is a nuisance in households -- and an expensive problem in thermal power stations, for example those that generate electricity, where the formation of limescale is known as fouling. Heat exchangers are particularly prone to limescale, which greatly reduces the efficiency of the systems: a layer of limescale just one millimetre thick in the heat exchanger's pipes reduces the efficiency of electricity production by approximately 1.5 percent. To compensate for these losses an additional 8.7 million tonnes of hard coal would have to be burned. That's bad for the carbon footprint and the climate, and it's expensive for the electricity producers.

BALTIMORE — Los Angeles Dodgers catcher Dalton Rushing left Friday’s 2-1 loss to the Baltimore Orioles after fouling a pitch off his leg in the top of the sixth inning. Rushing suffered a right lower leg contusion after he fouled off a pitch from Orioles right-hander Kade Strowd. Rushing was replaced by pinch-hitter Alex Call and then catcher Ben Rortvedt. Starting catcher Will Smith is not…