Solar and wind assisted biohydrogen production from integrated anaerobic digestion and microbial electrolysis cell coupled with catalytic reforming.

[Display omitted] • Dual-stage anaerobic digestion and microbial electrolysis are presented. • Catalytic biogas reforming with CO 2 capture are modelled. • Produced H 2 sales price is between $2/kg and $6/kg and the efficiency is ≥64%. • For the proposed work, 1 kg of produced H 2 can remove 10.92 kg of atmosphere CO 2. • Solar thermal and power and wind turbine systems replaced fossil fuels' combustion. To promote and improve the efficiency of biohydrogen production systems, an integrated AD and MEC (anaerobic digestion and microbial electrolysis cell) with catalytic syngas steam reforming (CSSR) was developed and simulated. This innovative integrated model predicts syngas formation from AD and MEC units, uses recovered heat for substrates pretreatment and solar parabolic dish (SPD) for heat source to decompose reformers' feeds. A combined 46 degradation reactions were used for acidogenesis, acetogenesis, and methanogenesis decomposition to predict syngas formation at different hydraulic retention time (HRT) and organic-loading rate (OLR). Biogas consisted of C H 4 and C O 2 from both AD and MEC were the CSSR feeds. The electric units of the hybrid system were powered by solar cells and wind turbine systems. The by-product C O 2 was captured and collected for underground storage. Controlled pH value, thermal pretreatment of AD and MEC digestates, and equilibrium feed rate improve overall efficiency by >5% with minimal volatile fatty acids (VFAs) and H 2 S production. The results show that the developed system can accommodate both waste and biomass feeds with 64% system efficiency. The stated efficiency excluded power generation units (solar and wind). The H 2 sales price of this developed system is between $2/kg and $6/kg. However, by installing this proposed system in areas with more sunlight during the day, a further reduction in H 2 price is possible. Adopting this new proposed technology means that for every 1kg of produced H 2 using biomass plants as feedstock and replanting used feedstocks, 10.92kg of C O 2 can be removed from the atmosphere because plants fix and store C O 2 in their roots. Meanwhile, the proposed work encouraged the use of waste feedstock instead of agricultural products without replanting. [ABSTRACT FROM AUTHOR]