(194g) Adsorption-Based Structural Characterisation of Carbonaceous Engine Deposits

Pinto da Costa, J. M. C. - Presenter, University of Edinburgh
Seaton, N. A. - Presenter, University of Edinburgh
Harrison, A. J. - Presenter, Shell Global Solutions

The adsorption-based structural characterization of carbonaceous porous solids faces several challenges due to the complexity of the internal structure and chemical composition of these materials. A widely adopted approach in characterization of activated carbons combines molecular simulation, specifically grand canonical Monte Carlo (GCMC) in slit pores, and experimental adsorption isotherms to determine the pore size distribution (PSD). The objective of this study is to extend this approach to more complex carbonaceous materials. For this we propose a general protocol, where solid-fluid interaction is systematically modified to account for the chemical and structural heterogeneity of the material.

We apply this approach to a specific case of engine deposits, complex carbonaceous materials that tend to accumulate on the inner surfaces of the car engine. These deposits represent a great challenge for the automotive industry in the optimization of engine performance. The proposed approach enables us to extract the PSDs of these materials and to investigate their adsorption properties under different conditions of temperature and pressure, based on the obtained PSD. Specifically, using the experimental data from a single ethane isotherm at 278K we are able to accurately predict ethane adsorption at other temperatures and in other samples, as well as adsorption of other more complex molecules present in fuel and combustion products. We believe the presented strategy can be extended to other complex porous carbons.