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[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]

[Display omitted] • Innovative solar-driven pyrolysis systems are proposed for clean hydrogen generation. • Desulphurisation of methane feedstock to minimise catalyst deactivation. • The integrated systems include electrolysis and molten salt for thermal energy storage (TES). • The hybrid system includes carbon capture and the use of recovered heat to generate electricity. • Process simulation and sensitivity analysis for the study of reactions' parameters. Reduction of carbon emissions from conventional gray Hydrogen (H 2) production is a promising option in moving towards much greener H 2 generation. To minimise carbon emissions and improve plants' efficiencies of conventional gray H 2 production, this study focused on process simulation of hybrid CSP, catalytic Methane (CH 4) and biomass pyrolysis and Water (H 2 O) electrolysis plants with 1000 °C HTF output temperature. This integrated system differs from current pyrolysis and electrolysis technologies for H 2 production because of the involvement of CSP as a thermal energy source; the use of part of recovered heat from the reactor to power downstream units including thermolysis of Sulphuric Acid (H 2 S O 4) and steam generation for both H 2 O electrolysis and Rankine cycle; the use of H 2 O as a reaction media and carbon looping to promote biomass decomposition; anodic oxidation of SO 2 in AEC to promote hydrogen evolution reaction. In that regard, CSP systems were modelled and simulated in SAM and MATLAB software. The output result of the simulated CSP system got exported to the Simulink to feed simulated CH 4 and biomass pyrolysis coupled with TES and Rankine cycle from Aspen plus. In addition, simulated thermal disassociation of H 2 S O 4 , electrolysis of H 2 O with SOEC and AEC from Aspen plus was also exported to the Simulink to feed the CSP system. Both integrated systems were fed with CH 4 as the working fluid of the solar furnace. About $1.7/kg is estimated to be a H 2 selling price for simulated pyrolysis of CH 4 and biomass plant which is cheaper than SMR with a CCS system. While between 4.6 and 10.48 is also estimated to be a H 2 selling price for another simulated CH 4 pyrolysis and H 2 O electrolysis. Just like existing CSP systems for electricity generation, both simulated hybrid systems generate electricity for up to 200 min in the absence of the Sun. Similar to SMR with a CCS system, C O 2 by-product from biomass pyrolysis was captured. Due to coking issues related to catalytic pyrolysis, noncatalytic pyrolysis of CH 4 was investigated. Results of the research work show that a return on investment within a period of 6 years is possible with the adoption of these new innovative technologies while reducing carbon footprints in H 2 generation plants. [ABSTRACT FROM AUTHOR]

• A new microcombustor is designed for renewables to power 12 kWe turbine. • The combustor was modeled to analyze the renewable fuels (energy eff., etc). • The exo-energy optimization of the combustor is made using a defined objective function. • The economic benefits are given for the microturbine with new combustor. The ever-increasing demand on highly efficient decentralized power generation with low CO 2 emission has made microturbines for power generation in micro gas turbine (MGT) systems popular when running on biofuels as a renewable source of energy. This document presents a state-of-the-art design, and optimization (in terms of design, performance and emission control) of a micro-turbine renewable energy combustor that fits into the existing Bladon 12kWe recuperated microturbine plenum while running on a range of biofuels as it can successfully provide the required power of the MGT. Governing equations for in-depth analysis of the combustor consist of manufacturer empirical data to simulate system-level operation with respect to replacement of the fossil with biofuels. The Model developed and validated at the company's ISO conditions confirms the output power of the new combustor fits the conventional system with slight eco-energy improvements. The modeling of the combustor in a complete microturbine assembly system is performed, then was utilized to further analysis of the microturbine with the designed combustor. The results gave on average 46.7% electrical efficiency, 83.2% system efficiency, 12 kWe electrical power, and 90% recuperator effectiveness at nominal operating conditions of microturbine (MT). Sensitivity analyses evaluate changes in performance with respect to fuel phase (e.g., liquid or gaseous) and design variables (e.g., orientation, shape, and dimensions of combustor), leading to energy optimization of the unit. Findings demonstrate that the combustor in microturbine can meet the target performance specifications of a company conventional diesel microturbine with significant savings. An objective function including both combustor and recuperator technical energy data is defined for finding the best ratio of fuel and air and their flow rates to find the most effective operating points for the operation of MT. Annual time series simulations completed for Coventry, West Midlands, United Kingdom indicate a new combustor can reduce operational costs of diesel fuel combustor by 8%, 2%, 36%, and 25% when supplying bioethanol, DME, biogas, and NG, respectively. Annual operating time of the renewable microturbine combustor at rated capacity included an 11% reduction in exergy loss with biogas fuel relative to diesel fuel. [ABSTRACT FROM AUTHOR]