The objective of the proposed project is to define and develop new, advanced and efficient catalytic techniques, and compact economic process technologies for the abatement of N20 in industrial off-gases.
The development will be based on the decomposition of N20 in nitrogen and oxygen and therefore in principle no additional reducing compounds will be necessary. This will result in relatively cheap processes, which can be easily controlled and operated. As for the composition and temperature of the off-gases to be treated, the work will be focussed on two specific application area's i.e. treatment of off-gases from specific N20-emitting chemical production and of fluidised bed waste combustion processes, which are representative with respect to the problems encountered in general. Since the requirements and circumstances for the two application area's differ, two process approaches are chosen. For the treatment of chemical process off-gases an innovative dual-step process will be investigated, consisting of a preconcentration step on an inorganic sorbent-catalyst at the process temperature of the off-gases, followed by regeneration of the spent sorbent-catalyst by catalyzed desorption/conversion in a two-section reactor system at reaction temperatures. In this approach the complete off-gas stream has not to be heated to reaction temperature, thus offering economical and energytical advantages. Sorbent-catalyst systems based on zeolites and/or mixtures with metal oxides on ceramic monoliths will be investigated. With these catalyst systems a number of potential technological problems, such as insufficient residence times and catalyst flooding can be avoided. In the case of waste combustion off-gases, a simple one stage in-situ fixed-bed or monolith catalytic decomposition process could be sufficient and is thus proposed in the project. Either zeolite type catalysts, novel zirconium oxide based catalysts and/ or mixtures will be explored. Due to the presence of various possible contaminants and deactivating agents, the industrial objective requires the development of active catalysts stable over a meaningful time of operation.
The two process approaches will be evaluated by a combination of process specific catalyst system development and testing, and lab- and bench scale experiments. The work will be supported by basic studies. The results will be used for a sequence of technical and economic evaluation studies to be made in course of the project by the industrial partners with the final aim to judge the feasibility of application of the processes under industrial conditions. Target objectives for both applications are:
- To reach levels of N20 abatement from the gaseous stream of at least 90 %; - To have stable catalytic performances in the presence of simulated off-gas for at least 500 hours of continuous operation.
Funding SchemeCSC - Cost-sharing contracts
30175 Mestre Venezia
PA4 8DJ Renfrew
02044 Espoo - Vtt