The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform

Rangan Banerjee - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of biohydrogen production processes
    International Journal of Hydrogen Energy, 2008
    Co-Authors: Sinha Manish, Rangan Banerjee
    Abstract:

    For hydrogen to be a viable energy carrier, it is important to develop hydrogen generation routes that are renewable like biohydrogen. Hydrogen can be produced biologically by Biophotolysis (direct and indirect), photo-fermentation and dark-fermentation or by combination of these processes (such as integration of dark- and photo-fermentation (two-stage process), or biocatalyzed electrolysis, etc.). However, production of hydrogen by these methods at commercial level is not reported in the literature and challenges regarding the process scale up remain. In this scenario net energy analysis (NEA) can provide a tool for establishing the viability of different methods before scaling up. The analysis can also be used to set targets for various process and design parameters for bio-hydrogen production. In this paper, four biohydrogen production processes (dark-fermentation, photo-fermentation, two-stage process and biocatalyzed electrolysis) utilizing sugarcane juice as the carbon source, are compared with base case method steam methane reforming (SMR) on the basis of net energy ratio, energy efficiency and greenhouse gas (GHG) emissions. It was found that when by-products are not considered, the efficiencies of biological hydrogen processes are lower than that of SMR. However, these processes reduce GHG emissions and non-renewable energy use by 57-73% and 65-79%, respectively, as compared to the SMR process. Efficiencies of biohydrogen processes increase significantly when by-products are considered hence by-products removal and utilization is an important issue in biological hydrogen production. © 2007 International Association for Hydrogen Energy.

  • Comparison of biohydrogen production processes
    International Journal of Hydrogen Energy, 2008
    Co-Authors: Sinha Manish, Rangan Banerjee
    Abstract:

    Abstract For hydrogen to be a viable energy carrier, it is important to develop hydrogen generation routes that are renewable like biohydrogen. Hydrogen can be produced biologically by Biophotolysis (direct and indirect), photo-fermentation and dark-fermentation or by combination of these processes (such as integration of dark- and photo-fermentation (two-stage process), or biocatalyzed electrolysis, etc.). However, production of hydrogen by these methods at commercial level is not reported in the literature and challenges regarding the process scale up remain. In this scenario net energy analysis (NEA) can provide a tool for establishing the viability of different methods before scaling up. The analysis can also be used to set targets for various process and design parameters for bio-hydrogen production. In this paper, four biohydrogen production processes (dark-fermentation, photo-fermentation, two-stage process and biocatalyzed electrolysis) utilizing sugarcane juice as the carbon source, are compared with base case method steam methane reforming (SMR) on the basis of net energy ratio, energy efficiency and greenhouse gas (GHG) emissions. It was found that when by-products are not considered, the efficiencies of biological hydrogen processes are lower than that of SMR. However, these processes reduce GHG emissions and non-renewable energy use by 57–73% and 65–79%, respectively, as compared to the SMR process. Efficiencies of biohydrogen processes increase significantly when by-products are considered hence by-products removal and utilization is an important issue in biological hydrogen production.

Patrick C Hallenbeck - One of the best experts on this subject based on the ideXlab platform.

  • strategies for improving biological hydrogen production
    Bioresource Technology, 2012
    Co-Authors: Patrick C Hallenbeck, Mona Abohashesh, Dipankar Ghosh
    Abstract:

    Biological hydrogen production presents a possible avenue for the large scale sustainable generation of hydrogen needed to fuel a future hydrogen economy. Amongst the possible approaches that are under active investigation and that will be briefly discussed; Biophotolysis, photofermentation, microbial electrolysis, and dark fermentation, dark fermentation has the additional advantages of largely relying on already developed bioprocess technology and of potentially using various waste streams as feedstock. However, the major roadblock to developing a practical process has been the low yields, typically around 25%, well below those achievable for the production of other biofuels from the same feedstocks. Moreover, low yields also lead to the generation of side products whose large scale production would generate a waste disposal problem. Here recent attempts to overcome these barriers are reviewed and recent progress in efforts to increase hydrogen yields through physiological manipulation, metabolic engineering and the use of two-stage systems are described.

  • biological hydrogen production fundamentals and limiting processes
    International Journal of Hydrogen Energy, 2002
    Co-Authors: Patrick C Hallenbeck, John R Benemann
    Abstract:

    Abstract Biological hydrogen production has been known for over a century and research directed at applying this process to a practical means of hydrogen fuel production has been carried out for over a quarter century. The various approaches that have been proposed and investigated are reviewed and critical limiting factors identified. The low energy content of solar irradiation dictates that photosynthetic processes operate at high conversion efficiencies and places severe restrictions on photobioreactor economics. Conversion efficiencies for direct Biophotolysis are below 1% and indirect Biophotolysis remains to be demonstrated. Dark fermentation of biomass or wastes presents an alternative route to biological hydrogen production that has been little studied. In this case the critical factor is the amount of hydrogen that can be produced per mole of substrate. Known pathways and experimental evidence indicates that at most 2– 3 mol of hydrogen can be obtained from substrates such as glucose. Process economics require that means be sought to increase these yields.

J Benemann - One of the best experts on this subject based on the ideXlab platform.

  • Feasibility analysis of photobiological hydrogen production
    International Journal of Hydrogen Energy, 2002
    Co-Authors: J Benemann
    Abstract:

    Photobiological production of hydrogen from water (Biophotolysis) requires efficient biological converters, microalgae, and low cost photobioreactors. Microalgal strains must be developed that exhibit high hydrogen production rates and photosynthetic efficiencies in dense cultures at full solar intensities. The photobioreactor must expose the H2 producing cultures to sunlight, while allowing recovery of the gas. A preliminary analysis is presented of a two stage process in which microalgae are cultivated in large open ponds to produce a high carbohydrate biomass that then produces hydrogen in tubular photobioreactors. Photobioreactors constructed of inexpensive, commercially available, glass tubes are proposed for such applications. Photobiological hydrogen production requires long-term research and development. However it could be of lower cost than systems based on electrolysis of water using photovoltaic electricity—the current system of choice for solar hydrogen production.

Yagut Allahverdiyeva - One of the best experts on this subject based on the ideXlab platform.

  • water oxidation by photosystem ii is the primary source of electrons for sustained h2 photoproduction in nutrient replete green algae
    Proceedings of the National Academy of Sciences of the United States of America, 2020
    Co-Authors: Sergey Kosourov, Valeria Nagy, Dmitry Shevela, Martina Jokel, Johannes Messinger, Yagut Allahverdiyeva
    Abstract:

    The unicellular green alga Chlamydomonas reinhardtii is capable of photosynthetic H2 production. H2 evolution occurs under anaerobic conditions and is difficult to sustain due to 1) competition between [FeFe]-hydrogenase (H2ase), the key enzyme responsible for H2 metabolism in algae, and the Calvin–Benson–Bassham (CBB) cycle for photosynthetic reductants and 2) inactivation of H2ase by O2 coevolved in photosynthesis. Recently, we achieved sustainable H2 photoproduction by shifting algae from continuous illumination to a train of short (1 s) light pulses, interrupted by longer (9 s) dark periods. This illumination regime prevents activation of the CBB cycle and redirects photosynthetic electrons to H2ase. Employing membrane-inlet mass spectrometry and H 2 18 O , we now present clear evidence that efficient H2 photoproduction in pulse-illuminated algae depends primarily on direct water Biophotolysis, where water oxidation at the donor side of photosystem II (PSII) provides electrons for the reduction of protons by H2ase downstream of photosystem I. This occurs exclusively in the absence of CO2 fixation, while with the activation of the CBB cycle by longer (8 s) light pulses the H2 photoproduction ceases and instead a slow overall H2 uptake is observed. We also demonstrate that the loss of PSII activity in DCMU-treated algae or in PSII-deficient mutant cells can be partly compensated for by the indirect (PSII-independent) H2 photoproduction pathway, but only for a short (

Sinha Manish - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of biohydrogen production processes
    International Journal of Hydrogen Energy, 2008
    Co-Authors: Sinha Manish, Rangan Banerjee
    Abstract:

    For hydrogen to be a viable energy carrier, it is important to develop hydrogen generation routes that are renewable like biohydrogen. Hydrogen can be produced biologically by Biophotolysis (direct and indirect), photo-fermentation and dark-fermentation or by combination of these processes (such as integration of dark- and photo-fermentation (two-stage process), or biocatalyzed electrolysis, etc.). However, production of hydrogen by these methods at commercial level is not reported in the literature and challenges regarding the process scale up remain. In this scenario net energy analysis (NEA) can provide a tool for establishing the viability of different methods before scaling up. The analysis can also be used to set targets for various process and design parameters for bio-hydrogen production. In this paper, four biohydrogen production processes (dark-fermentation, photo-fermentation, two-stage process and biocatalyzed electrolysis) utilizing sugarcane juice as the carbon source, are compared with base case method steam methane reforming (SMR) on the basis of net energy ratio, energy efficiency and greenhouse gas (GHG) emissions. It was found that when by-products are not considered, the efficiencies of biological hydrogen processes are lower than that of SMR. However, these processes reduce GHG emissions and non-renewable energy use by 57-73% and 65-79%, respectively, as compared to the SMR process. Efficiencies of biohydrogen processes increase significantly when by-products are considered hence by-products removal and utilization is an important issue in biological hydrogen production. © 2007 International Association for Hydrogen Energy.

  • Comparison of biohydrogen production processes
    International Journal of Hydrogen Energy, 2008
    Co-Authors: Sinha Manish, Rangan Banerjee
    Abstract:

    Abstract For hydrogen to be a viable energy carrier, it is important to develop hydrogen generation routes that are renewable like biohydrogen. Hydrogen can be produced biologically by Biophotolysis (direct and indirect), photo-fermentation and dark-fermentation or by combination of these processes (such as integration of dark- and photo-fermentation (two-stage process), or biocatalyzed electrolysis, etc.). However, production of hydrogen by these methods at commercial level is not reported in the literature and challenges regarding the process scale up remain. In this scenario net energy analysis (NEA) can provide a tool for establishing the viability of different methods before scaling up. The analysis can also be used to set targets for various process and design parameters for bio-hydrogen production. In this paper, four biohydrogen production processes (dark-fermentation, photo-fermentation, two-stage process and biocatalyzed electrolysis) utilizing sugarcane juice as the carbon source, are compared with base case method steam methane reforming (SMR) on the basis of net energy ratio, energy efficiency and greenhouse gas (GHG) emissions. It was found that when by-products are not considered, the efficiencies of biological hydrogen processes are lower than that of SMR. However, these processes reduce GHG emissions and non-renewable energy use by 57–73% and 65–79%, respectively, as compared to the SMR process. Efficiencies of biohydrogen processes increase significantly when by-products are considered hence by-products removal and utilization is an important issue in biological hydrogen production.