Underground Diesel Exhaust Wet Scrubbers: Current Status and Future Prospects

Diesel engines release a range of harmful components into the environment in the form of gases, liquids, and particulate matter (PM). These components have a direct and indirect impact on human health and climate change. Wet scrubbers are used to clean diesel exhaust emissions, by bubbling them through a liquid (usually water) to reduce their temperature and remove some soluble components and particles. Then, these emissions pass through a filter to remove further diesel particulate matter. The PM-capturing mechanism, heat transfer mechanism, and fluid mechanism of a wet scrubber are reviewed. Several parameters have a major influence on wet scrubber performance, such as inlet gas velocity. Modeling of a wet scrubber can be conducted through thermodynamics analysis, heat transfer analysis, and computational simulation. These investigations may lead to optimizing wet scrubber performance, and then to reducing both humidity and temperature at the scrubber exit. This humidity reduction increases filter life and reduces maintenance costs.