Development of an ASPEN Plus Model of a Chemical-Looping Reformer Reactor

Synthetic Natural Gas (SNG) from biomass gasification is viewed as a promising option for production of transport fuels. A major problem associated is the removal of contaminants derived from the gasification step, such as tars. Tars are aromatic compounds, usually between 1 and 5 rings, which at 350˚C already start to condensate, causing clogging and blockage of components. Catalytic tar conversion presents advantages compared to other technologies and in particular it allows thermal integration with the gasification step, lowering the thermodynamic losses, and enables the use of the energy contained in the tars by converting them into usable gases, such as H2 and CO. Catalyst deactivation can be caused by coke deposits. A novel technique named Chemical-looping reforming (CLR), based on Chemical-looping combustion concept (CLC), is being developed in Chalmers University of Technology to tackle this problem. It is based in a two reactor system, one Fuel reactor (FR) and an Air reactor (AR). In the FR the tars are oxidized due to the reduction of the catalyst. In the AR the catalyst is newly oxidized and the coke deposits are combusted. The present work intends to analyze raw data, measured from a bench-size CLR facility using different catalysts and O2 concentrations in the AR, in order to elaborate a descriptive model of the system in order to assess how the reforming step influences the fate of the incondensable gases (H2, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H8, and N2) This is achieved by firstly elaborating a molar balance to both reactors taking into account the system main constitutes (Carbon, Oxygen, Hydrogen and Nitrogen) and afterwards implementing it in Matlab, in order to solve the balance. The model was elaborated using commercial flow-sheet software called Aspen Plus