Process and reactor design for biophotolytic hydrogen production

Abstract

The green alga Chlamydomonas reinhardtii has the ability to produce molecular hydrogen (H 2 ), a clean and renewable fuel, through the biophotolysis of water under sulphur-deprived anaerobic conditions. The aim of this study was to advance the development of a practical and scalable biophotolytic H 2 production process. Experiments were carried out using a purpose-built flat-plate photobioreactor, designed to facilitate green algal H 2 production at the laboratory scale and equipped with a membrane-inlet mass spectrometry system to accurately measure H 2 production rates in real time. The nutrient control method of sulphur deprivation was used to achieve spontaneous H 2 production following algal growth. Sulphur dilution and sulphur feed techniques were used to extend algal lifetime in order to increase the duration of H 2 production. The sulphur dilution technique proved effective at encouraging cyclic H 2 production, resulting in alternating Chlamydomonas reinhardtii recovery and H 2 production stages. The sulphur feed technique enabled photobioreactor operation in chemostat mode, resulting in a small improvement in H 2 production duration. A conceptual design for a large-scale photobioreactor was proposed based on these experimental results. This photobioreactor has the capacity to enable continuous and economical H 2 and biomass production using green algae.The success of these complementary approaches demonstrate that engineering advances can lead to improvements in the scalability and affordability of biophotolytic H 2 production, giving increased confidence that H 2 can fulfil its potential as a sustainable fuel of the future.

Modelling light transmission, cyanobacterial growth kinetics and fluid dynamics in a laboratory scale multiphase photo-bioreactor for biological hydrogen production

“…1) was designed and operated for microalgal hydrogen production [20,22]. This reactor has the advantage of a high surface-to-volume ratio, which can offer a large illumination surface area.…”

The Effect of Diel Temperature and Light Cycles on the Growth of Nannochloropsis oculata in a Photobioreactor Matrix

“…Conducting field trials in these large-scale facilities is expensive and time-consuming. A more practical approach is to use laboratory-scale PBRs to simulate natural environmental conditions at the anticipated commercial location; however, most indoor laboratory-scale devices do not fully simulate the outdoor daily cycles of light intensity and temperature [17]–[19]. A series of custom-built PBRs (ePBR, Phenometrics, Lansing, MI, USA) have been integrated with metabolic sensors to simulate outdoor algal growth conditions in the laboratory.…”

Demonstration of a two-stage aerobic/anaerobic chemostat for the enhanced production of hydrogen and biomass from unicellular nitrogen-fixing cyanobacterium

“…One commonly employed technique is nutrient starvation. For example, sulphur-deprivation of the green alga Chlamydomonas reinhardtii [17][18][19] is found to effectively prohibit light-induced photosynthetic O 2 evolution, but does not affect cellular respiration. Under these conditions dissolved O 2 eventually becomes depleted and H 2 starts to evolve, albeit for a short period of up to 120 h [20].…”