Hydrogen production econometric studies

The current assessments of fossil fuel resources in the United States were examined, and predictions of the maximum and minimum lifetimes of recoverable resources according to these assessments are presented. In addition, current rates of production in quads/year for the fossil fuels were determined from the literature. Where possible, costs of energy, location of reserves, and remaining time before these reserves are exhausted are given. Limitations that appear to hinder complete development of each energy source are outlined

Phenomenological based model of hydrogen production using an alkaline self-pressurized electrolyzer

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The aim of this work is to develop the phenomenological based modeling of a self-pressurized alkaline electrolyser with the objective of predicting the cross-contamination of the gases produced. A proposed model, built in Matlab®, represents the dynamical evolution in real electrolysers, and anticipates operational variables: level, pressure and all concentrations. Dynamic responses in the concentrations of the electrolytic cell, and variations in both level and pressure at the chamber due to the change in current and diffusivity, are reported. The equations by which the variables can be computed are also presented. The proposed model is ready for the corresponding adjustment of parameters based on experimental measurements taken from an available prototype and through a suitable identification process.Peer ReviewedPostprint (author's final draft

Membrane reactor technology for ultrapure hydrogen production

The suitability of polymer electrolyte membrane fuel cells (PEMFC) for stationary and vehicular applications because of its low operating temperatures, compactness, higher power density, cleaner exhausts and higher efficiencies compared to conventional internal\ud combustion engines and gas turbines adds to the already soaring demand for hydrogen production for refinery and petrochemical applications

A nonmitochondrial hydrogen production in Naegleria gruberi

Naegleria gruberi is a free-living heterotrophic aerobic amoeba well known for its ability to transform from an amoeba to a flagellate form. The genome of N. gruberi has been recently published, and in silico predictions demonstrated that Naegleria has the capacity for both aerobic respiration and anaerobic biochemistry to produce molecular hydrogen in its mitochondria. This finding was considered to have fundamental implications on the evolution of mitochondrial metabolism and of the last eukaryotic common ancestor. However, no actual experimental data have been shown to support this hypothesis. For this reason, we have decided to investigate the anaerobic metabolism of the mitochondrion of N. gruberi. Using in vivo biochemical assays, we have demonstrated that N. gruberi has indeed a functional [FeFe]-hydrogenase, an enzyme that is attributed to anaerobic organisms. Surprisingly, in contrast to the published predictions, we have demonstrated that hydrogenase is localized exclusively in the cytosol, while no hydrogenase activity was associated with mitochondria of the organism. In addition, cytosolic localization displayed for HydE, a marker component of hydrogenase maturases. Naegleria gruberi, an obligate aerobic organism and one of the earliest eukaryotes, is producing hydrogen, a function that raises questions on the purpose of this pathway for the lifestyle of the organism and potentially on the evolution of eukaryotes

Economic analysis and optimization for bio-hydrogen production from oil palm waste via steam gasification

Biomass steam gasification with in-situ carbon dioxide capture using CaO exhibits good prospects for the production of hydrogen rich gas. In Malaysia, due to abundance of palm waste, it is a good candidate to be used as a feedstock for hydrogen production. The present work focuses on the mathematical modeling of detailed economic analysis and cost minimization of the flowsheet design for hydrogen production from palm waste using MATLAB. The influence of the operating parameters on the economics is performed. It is predicted that hydrogen cost decreasing by increasing both temperature and steam/biomass ratio. Meanwhile, the hydrogen cost increases when increasing sorbent/biomass ratio. Cost minimization solves to give optimum cost of 1.9105 USD/kg with hydrogen purity, hydrogen yield, hydrogen efficiency and thermodynamic efficiency are 79.9 mol%, 17.97 g/hr, 81.47% and 79.85% respectively. The results indicate that this system has the potential to offer low production cost for hydrogen production from palm waste

Hydrogen photo-production by mixotrophic cultivation of chlamydomonas reinhardtii: Interaction between organic carbon and nitrogen

Hydrogen photo-production by a wild type and two engineered strains of Chlamydomonas reinhardtii was investigated. Growth rate values and hydrogen yields attained as the concentration of acetate and nitrogen vary were compared. In the analysis of microalgal growth, the interaction between organic carbon (acetate) and nitrogen (nitrate) was investigated by recourse to an experimental factorial design. This analysis evidenced the existence of a statistically significant interaction between organic carbon and nitrate. Hydrogen production was attained by cultivating microalgae previously grown in mixotrophic regime with sulphur deprived medium. The influence of varying the photobioreactor headspace on hydrogen production was investigated. This analysis revealed an increase in the hydrogen produced per unit volume of culture of about one order of magnitude when the headspace volume is modified from 100 to 350 mL. This result provides valuable indications on how to design and operate photobioreactors for hydrogen production optimization and was thoroughly discussed in terms of the metabolic pathways activated by sulphur depletion. ©2014, AIDIC Servizi S.r.l

Effects of the preparation method of the ternary CdS/TiO_2/Pt hybrid photocatalysts on visible light-induced hydrogen production

A variety of combinations of CdS, TiO2, and Pt in preparing the hybrid catalysts were studied for hydrogen production under visible light ( > 420 nm) irradiation. The preparation method sensitively influenced the activity of the ternary hybrid catalysts. The formation of the potential gradient at the interface between CdS and TiO2 is necessary in achieving the efficient charge separation and transfer and how the platinum as a cocatalyst is loaded onto the CdS/TiO2 hybrid catalysts determines the overall hydrogen production efficiency. The common method of photoplatinization of CdS/TiO2 hybrid [Pt-(CdS/TiO2)] was much less efficient than the present method in which Pt was photodeposited on bare TiO2, which was followed by the deposition of CdS [CdS/(Pt-TiO2)]. The CdS/(Pt-TiO2) has the hydrogen production rate ranging (6–9) × 10-3 mol h-1 g-1, which is higher by a factor of 3–30 than that of Pt-(CdS/TiO2). The photocatalytic activity of the ternary hybrid catalysts was extremely sensitive to where the platinum is loaded. The photoactivity of the hybrid catalyst was also assessed in terms of the photocurrent collected by the methyl viologen electron shuttle in the catalyst suspension. CdS/(Pt-TiO2) generated higher photocurrents than Pt-(CdS/TiO2) by a factor of 2–7. The extreme sensitivity of the preparation method to the hydrogen production activity should be taken into account when hybrid photocatalysts are designed and prepared

Nonlinear model predictive control for hydrogen production in an ethanol steam reformer with membrane separation

© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThis paper presents a new Nonlinear Model Predictive Control (NMPC) design for an Ethanol Steam Reformer with Pd-Ag membrane separation stage. The reformer is used to produce pure hydrogen able to feed a Proton Exchange Membrane Fuel Cell. Mass and energy balances are used to obtain the nonlinear dynamic model of both the reforming and the separation stages. Constraints, system nonlinearities and flexible cost function are the main reasons to select an NMPC controller, which is tested against the ordinary differential equations as simulation model, and has an internal model based on the sample data technique.Accepted versio

Increased hydrogen production by Escherichia coli strain HD701 in comparison with the wild-type parent strain MC4100

Hydrogen production by Escherichia coli is mediated by the formate hydrogenlyase (FHL) complex. E. coli strain HD701 cannot synthesize the FHL complex repressor, Hyc A. Consequently, it has an up-regulated FHL system and can, therefore, evolve hydrogen at a greater rate than its parental wild type, E. coli MC4100. Resting cells of E. coli strain HD701 and MC4100 were set up in batch mode in\ud phosphate buffered saline (PBS) to decouple growth from hydrogen production at the expense of sugar solutions of varying composition. Strain HD701 evolved several times more hydrogen than MC4100 at glucose concentrations ranging from 3 to 200 mM. The difference in the amount of H2 evolved by both strains decreased as the concentration of glucose increased. The highest rate of H2 evolution by strain HD701was 31ml h−1 ODunit −1 l−1 at a glucose concentration of 100 mM.With strain MC4100, the highest ratewas 16ml h−1 ODunit −1 l−1 under these conditions. Experiments using industrial wastes with a high sugar content yielded similar results. In each case, strain HD701\ud evolved hydrogen at a faster rate than the wild type, showing a possible potential for commercial hydrogen production