Thermal management in porous ceramic particulate filters: Opportunities and consequences of plasma technology solutions for particulate filter regeneration [Powerpoint]
We remain dependent on combustion sources for many of our essential energy systems, continuously improving technologies to minimise the negative impacts of the energy use on our environment. Local air quality in urban areas is of particular concern and has led to increasingly stringent legislation being applied to the energy sector. Reduction of particulate emissions from combustion sources is being effectively tackled through pre-combustion approaches (e.g. fuel quality), through combustion optimisation and by implementing exhaust gas aftertreatment systems such as monolithic ceramic particulate filters. Although a wide range of types of particulate filters exist, they all require cleaning to avoid excessive pressure drops across the substrate as the amount of trapped particulates increase. Typically this is done through oxidation of the trapped particles, requiring filters that are capable of withstanding high temperatures, high temperature gradients and both reducing and oxidising environments. Significant opportunities exist within the industry to improve vehicle efficiency and reduce cost by developing new and improved regeneration systems. Medium (>1000 K) and high temperature (>10,000 K) plasma technologies for particulate filter regeneration are introduced with a particular focus on their interaction with porous ceramic substrates. When used effectively, no observable damage is present. However, there exists engineering conflicts between minimising energy consumption, achieving fast regeneration and maintaining substrate durability. This conflict is presented showing the limits of current technology. It identifies two clear opportunities. Firstly, the recent application of pulsed plasmas to cordierite substrates demonstrates the opportunities for developing lower thermal requirement (and potentially lower cost substrates). Secondly, how advances in local substrate thermal characteristics can enable significant improvements in efficacy of oxidative plasma solutions
