The most interesting technology for biomass conversion currently under development is flash pyrolysis for the production of liquids for recovery of high value chemical specialties and commodities. The objectives of the work are to operate and optimize the performance of two laboratory scale pyrolysis reactors in order to derive an optimum configuration and jointly develop a common modelling procedure for scale-up. Associated objectives include assessment of the potential to recover high value speciality chemicals and commodities from the liquid products and determination of basic physical and physio-chemical properties. The possibility of using the residual liquid as an alternative fuel will also be assessed as valorization of this material is essential for economic viability of an integrated process.
Two different 5kg/h ablative pyrolysis reactors have been constructed and commissioned. A thorough and intensive experimental programme is necessary to compare, evaluate and optimise the reactors' performance. A common approach to product collection system involving direct quenching of the product vapours is being designed and constructed. The results show that high yields of liquids up to 75 wt% can be obtained. The benefits of this approach compared to conventional flash pyrolysis are a more compact reactor design with correspondingly reduced equipment costs, higher heat transfer coefficients and higher specific throughput. Information on the yields of solid char, liquids and gases will allow models to be developed with the University of Naples for ablative pyrolysis to assist in further design work for the engineering scale-up by both Aston and Twente Universities. An essential part of the design process for new technologies is robust modelling of the reaction phenomena. This aspect of the project will develop existing models and apply them to the pyrolysis processes under investigation. The joint development of related technologies at Aston and Twente will permit more comprehensive and thorough models to be developed. These will aid scale-up, optimization, and provide more reliable designs.
The pyrolysis liquid contains a wide variety of highly oxygenated organic compounds. Some chemicals can be recovered by direct extraction, and there is potential in catalytic upgrading to specific products or families of compounds. All work to date has focused on de-oxygenation for liquid fuels by hydrotreating or zeolite cracking. This work will examine novel catalyst systems to exploit the state of the art and develop new catalysts, new products and new processes. The work will utilize a continuous microreactor system for rapid screening of a range of modified conventional and novel catalysts.
Physio-chemical properties are essential for design and scale up of flash pyrolysis and upgrading systems and specification of applications. There is no data available on any relevant properties, and extrapolation of data on orthodox hydrocarbons can lead to major over-or under-design with correspondingly technical uncertainties and economic consequences. Products from both pyrolysers and upgrading work will be examined and compared to other pyrolysis liquids and products.
Funding SchemeCSC - Cost-sharing contracts