Biowaste to hydrogen or Fischer-Tropsch fuels by gasification – A Gibbs energy minimisation study for finding carbon capture potential and fossil carbon displacement on the road

Abstract

To reach its greenhouse gas emission reduction goals, Norway needs a shift away from the use of fossil fuels in the transport sector. The production potential and efficiency of Fischer-Tropsch biofuels and hydrogen from gasified wet organic municipal solid waste has been investigated. The carbon capture potential was estimated for both production processes and the number of road vehicles compared, which can be supplied with the fuel. Gibbs free energy minimisation is used to predict the synthesis gas composition. A detailed analysis of the different gas treatment processes that lead to either gasoline and diesel production, along with energy recovery as electricity, or hydrogen in either compressed or liquefied form is conducted. Both processes can utilise all available waste heat and the Fischer-Tropsch biofuel process is even self-sufficient with electrical power. The production of hydrogen has both higher first and second law efficiencies and a greater number of vehicles can be supplied with fuel. Either 2367 tonne H2 or 1497 tonne gasoline, 1279 tonne diesel, and 1.33 MW of net electric power can be produced at 1073 K gasification temperature, where both yield and efficiencies are highest. Hydrogen production also has the larger carbon capture potential during fuel production.