Design and analysis of tubular photobioreactors for biohydrogen production

Kayahan, Emine
Hydrogen can be produced sustainably by utilizing organic wastes through photofermentation. In order to obtain an economically feasible operation, the photobioreactor design is of crucial importance. An optimal photobioreactor design should provide uniform velocity and light distribution, low pressure drop, low gas permeability and efficient gas-liquid separation. The aim of this study was to design a pilot-scale photobioreactor satisfying these criteria and to test the reactor under outdoor conditions with purple non sulphur bacteria. A glass, stacked tubular bioreactor aimed at satisfying these criteria has been designed for outdoor photofermentative hydrogen production. The design consists of 4 stacked U-tubes and 2 vertical manifolds. The hydrodynamics of the 3-dimensional model of this reactor was solved via COMSOL Multiphysics 4.1. Two reactors, whose volumes were 9 and 11 L, were constructed based on the dimensions obtained by the model. A reactor was constructed based on the dimensions obtained by the model. The reactor was operated with recirculation of culture containing Rhodobacter capsulatus YO3 (hup-). Every morning 10% of the culture was replaced by fresh feed. Experiments were lasted 10- 20 days. When molasses was used as the carbon source under outdoor conditions, the highest hydrogen productivity was found as 0.311 mol H2/(m3.h). Another parallel reactor working with acetic acid which was also run in July 2015, the highest productivity was found as 0.114 mol H2/(m3.h). Compared to nearly horizontal tubular reactors, the glass stacked tubular reactor design results in less ground area and longer life time.
Citation Formats
E. Kayahan, “Design and analysis of tubular photobioreactors for biohydrogen production,” M.S. - Master of Science, Middle East Technical University, 2015.