Simulation of a Hydrogen Production Process from Algae

Abstract

Sustainable sources of renewable energies are highly valuable in a world where the global energy demand is considerably increasing. The conceptualization of an efficient alternative fuel process production is based on the synergy of the reaction engineering, thermal integration, separation optimization, etc. Process simulation software are powerful tools that allows process designers to integrate these modules to get an optimized design: sustainable, environmentally friendly and cost efficient. A simulation model of the hydrogen production from micro-algae biomass was developed in Pro II. Algae are a rich source of carbohydrates. Sugars can be obtained by hydrolysis and then fermented to produce bioethanol which is consequently converted to hydrogen by catalytic reforming. The simulation was structured in three (3) main reaction units and corresponding side sub-units / equipment as separation trains, heat exchangers, etc. The first reaction unit is the enzymatic hydrolysis of micro-algae, based on the enzymatic hydrolysis of Chloroccum sp by using cellulase. The kinetics is fitted with Michaelis-Mente's model of rapid equilibrium, as described by Harun et. al (2010). The second reaction section is the bioethanol fermentation which is conducted in a converter reactor with a complementary FORTRAN subroutine. Downstream separation processes to refine the alcohols produced are also modelled. Finally the third reaction module includes the ethanol reforming over Ni Al2O3 catalyst as described by Akande et. al (2006). The simulation model allows users to analyse and optimise the process by using various process conditions, design configurations, energy integration options, etc.