Effect of extrinsic lactic acid on fermentative hydrogen production

In this paper we report the effect of extrinsic lactic acid on hydrogen production from a starch-containing medium by a mixed culture. Study of the effect of addition of four metabolites, namely ethanol, lactic acid, butyric acid and acetic acid illustrated that lactic acid had a positive effect on both the maximum hydrogen production and hydrogen production rate. The addition of 10 mM lactic acid to a batch containing starch increased the hydrogen production rate and hydrogen production yield from 4.31 to 8.23 mL/h and 5.70 to 9.08 mmol H₂/g starch, respectively. This enhancement in hydrogen production rate and yield was associated with a shift from acetic acid and ethanol formation to formation of butyric acid as the predominant metabolite. The increase in hydrogen production yield was attributed to the increase in the available residual NADH for hydrogen production. When lactic acid was used as the sole carbon source, no significant hydrogen production was observed.     

电解水制氢在电厂和氢能项目的设计应用

  目的  电解水制氢技术已普遍应用于燃煤电厂、燃气电厂和核电厂,也将更多地应用于可再生能源发电厂配套的氢能项目,有必要对制氢系统设计方案进行探讨。  方法  以某燃煤电厂和风力发电及太阳光伏发电厂配套氢能项目为例,依据相关标准规范的设计规定,阐述了相应的电解水制氢系统设计方案。  结果  碱性电解水制氢技术成熟、安全可靠,能为电厂氢冷发电机、加氢站和氢气用户持续提供满足纯度、湿度要求的氢气。  结论  文章旨在为更多电厂和氢能项目电解水制氢系统的设计提供可参考的方案。     

Advantages of integration with industry for electrolytic hydrogen production

This paper evaluates possible synergies with industry, such as heat and oxygen recovery from the hydrogen production. The hydrogen production technology used in this paper is electrolysis and the calculations include the cost and energy savings for integrated hydrogen production. Electrolysis with heat recovery leads to both cost reduction and higher total energy efficiencies of the hydrogen production. Today about 15–30% of the energy supplied for the production is lost and most of it can be recovered as heat. Utilization of the oxygen produced in electrolysis gives further advantages. The integration potential has been evaluated for a pulp and paper industry and the Swedish energy system, focusing on hydrogen for the transportation sector. The calculated example shows that the use of the by-product oxygen and heat greatly affects the possibility to sell hydrogen produced from electrolysis in Sweden. Most of the energy losses are recovered in the example; even gains in energy for not having to produce oxygen with cryogenic air separation are shown. When considering cost, the oxygen income is the most beneficial but when considering energy efficiency, the heat recovery stands for the greater part.     

Hydrogen refueling station siting of expressway based on the optimization of hydrogen life cycle cost

Hydrogen-energy expressway system planning involves load prediction, hydrogen source planning and hydrogen station planning. Exemplary construction of a run-for-profit hydrogen-energy expressway must attach importance to comprehensive evaluation of the effect of investment. The paper analyzes current situation of hydrogen-energy expressway construction, points out that adequate consideration should be given in all aspects of hydrogen energy's life cycle cost, such as hydrogen production, transport, storage, usage, CO₂ disposal, carbon tax, hydrogen station's annual construction investment and annual operating expenses. The paper suggests that hydrogen made from discarded electricity of clean energies and hydrogen produced as byproduct during chemical plant production should be utilized to reduce production cost. On the basis of hydrogen energy's life cycle cost analysis, the paper creates a hydrogen station siting optimization model, with the constraints of hydrogen station's supply radius, hydrogen source's productivity and geographic information factor, so as to increase the applicability and level of hydrogen-energy expressway planning effectively.     

Opportunities for green hydrogen production in petroleum refining and ammonia synthesis industries in India

Increasing penetration of renewable electricity in the power systems coupled with reduction in its cost has resulted in increased interest in green hydrogen globally. Industry has been using fossil fuel-based hydrogen as an input for several decades. This paper makes an assessment of existing hydrogen production capacities in petroleum refineries and ammonia synthesis units in India along with estimating the potential for installing solar photovoltaic (SPV) powered alkaline electrolysers for producing green hydrogen and SPV capacity required for this purpose. Levelised cost of hydrogen production in these industries in India has been analysed and found to be competitive. The paper also discusses about water requirement, land requirement for SPV power plants, CO₂ emissions avoided and likely investment to be made for establishing infrastructure for green hydrogen production. With launching of national hydrogen mission in India, a transition to green hydrogen by the industry appears to be a near term possibility.     

Assessment of hydrogen supply solutions for hydrogen fueling station: A Shanghai case study

Shanghai is one of the fastest growing regions of hydrogen energy in China. This paper researched feasible hydrogen sources in both internal and external Shanghai. This study comes up 9 hydrogen production methods and 6 transportation routes, ultimately forms 12 hydrogen supply solutions according to local conditions. The total cost in each solution is estimated including processes of hydrogen production, treatments, storage and transportation based on different transport distance. The results indicate that hydrogen supply cost is above 50 CNY/kgH₂ for external hydrogen sources after long-distance transportation to Shanghai, such as hydrogen production from coal in Inner Mongolia and from renewables in Hebei. The total cost of on-site hydrogen production from natural gas can be controlled under 40 CNY/kgH₂. When the price of wind power reduces to 0.5 CNY/kWh, hydrogen production from offshore wind power cooperating with hydrogen pipeline network has the greatest development potential for Shanghai hydrogen supply.     

A GIS-based assessment of coal-based hydrogen infrastructure deployment in the state of Ohio

Hydrogen infrastructure costs will vary by region as geographic characteristics and feedstocks differ. This paper proposes a method for optimizing regional hydrogen infrastructure deployment by combining detailed spatial data in a geographic information system (GIS) with a technoeconomic model of hydrogen infrastructure components. The method is applied to a case study in Ohio in which coal-based hydrogen infrastructure with carbon capture and storage (CCS) is modeled for two distribution modes at several steady-state hydrogen vehicle market penetration levels. The paper identifies the optimal infrastructure design at each market penetration as well as the costs, CO₂ emissions, and energy use associated with each infrastructure pathway. The results indicate that aggregating infrastructure at the regional-scale yields lower levelized costs of hydrogen than at the city-level at a given market penetration level, and centralized production with pipeline distribution is the favored pathway even at low market penetration. Based upon the hydrogen infrastructure designs evaluated in this paper, coal-based hydrogen production with CCS can significantly reduce transportation-related CO₂ emissions at a relatively low infrastructure cost and levelized fuel cost.     

Hydrogen production for energy: An overview

Power to hydrogen is a promising solution for storing variable Renewable Energy (RE) to achieve a 100% renewable and sustainable hydrogen economy. The hydrogen-based energy system (energy to hydrogen to energy) comprises four main stages; production, storage, safety and utilisation. The hydrogen-based energy system is presented as four corners (stages) of a square shaped integrated whole to demonstrate the interconnection and interdependency of these main stages. The hydrogen production pathway and specific technology selection are dependent on the type of energy and feedstock available as well as the end-use purity required. Hence, purification technologies are included in the production pathways for system integration, energy storage, utilisation or RE export. Hydrogen production pathways and associated technologies are reviewed in this paper for their interconnection and interdependence on the other corners of the hydrogen square.Despite hydrogen being zero-carbon-emission energy at the end-use point, it depends on the cleanness of the production pathway and the energy used to produce it. Thus, the guarantee of hydrogen origin is essential to consider hydrogen as clean energy. An innovative model is introduced as a hydrogen cleanness index coding for further investigation and development.     

Efficient hydrogen production from lignocellulosic feedstocks by a newly isolated thermophlic Thermoanaerobacterium sp. strain F6

Consolidated bioprocessing (CBP) is a promising approach for hydrogen production from lignocellulose owing to its lower cost and higher efficiency. In this study, the newly isolated theromphilic Thermoanaerobacterium sp. strain F6 exhibited the capability of direct utilization of various hemicellulosic and cellulosic materials for hydrogen production, including xylan, Avicel and filter paper etc. Especially, the maximum cumulative hydrogen production reached 370.7 mmoL/L from 60 g/L of xylan. In addition, natural lignocellulosic materials, such as corn cob and sugarcane bagasse without any hydrolytic pretreatment could also be directly utilized as the sole carbon source for hydrogen production. 1822.6 and 826.3 mL H₂/L of hydrogen were produced from corn cob and sugarcane bagasse, respectively. The high hydrogen production from cellulosic and hemicellulosic materials were both benefit from its efficient secretion of hydrolytic enzymes. Thus, Thermoanaerobacterium sp. strain F6 is a potential candidate for effective conversion of lignocellulose to hydrogen through CBP.     

Large capacity hydrogen production by microwave discharge plasma in liquid fuels ethanol

In situ hydrogen production technologies have attracted attentions because of hydrogen storage and transportation safety issues. Discharge plasma technology for hydrogen production is of fast response, large capacity, small scale and portability, which is suitable for automobiles and ships. In this paper, a method for producing hydrogen by microwave discharge in ethanol solution was introduced. A microwave discharge reactor of direct standing wave coupling (MDRSWC) was designed, which was suitable for on-board hydrogen production. The characteristics of large capacity hydrogen production by applying MDRSWC in liquid ethanol were investigated. Depending on the experimental conditions of ethanol concentration and microwave power, the flow rate of hydrogen production was achieved ranging from 28.93 to 72.48 g/h. In addition to main hydrogen and carbon dioxide, a small amount of methane and acetylene as by-products were detected. By optimizing the experimental conditions, the experimental results showed that the flow rate of hydrogen, the percentage concentration of hydrogen and the energy yield of hydrogen production were 72.48 g/h, 58.1% and 48.32 g/kWh respectively. This work could provide a potentially effective hydrogen production method for on-board hydrogen utilization device.     

Measured effects of light intensity and catalyst concentration on photocatalytic hydrogen and oxygen production with zinc sulfide suspensions

In this paper, an experimental study is performed for hydrogen and oxygen production by new photo-catalytic and electro-catalytic water splitting systems. An effective method for hydrogen production by solar energy without consumption of additional reactants is a hybrid system which combines photo-chemical and electro-catalytic reactions. Experiments are performed in batch and dual cell quasi-steady operation with different light intensities and zinc sulfide photo-catalyst concentrations. The photo-reactor in batch operation achieves 6 mL h⁻¹ of hydrogen production with 3% w/v of catalyst. The hydrogen production rate corresponds to a quantum efficiency of 75% as measured through illumination of zinc sulfide suspensions in a dual cell reactor.     

The exploitation of hydrogen sulfide for hydrogen production in geothermal areas

Hydrogen is a valuable energy resource and it is widespread in nature. As a matter of fact, researches on hydrogen production are currently experiencing an increasing interest from scientists around the world since this resource is clean and renewable. Several methods of producing hydrogen have been developed in industrialized countries such as the United States of America and Germany.This paper is interested in the process by which hydrogen sulfide of geothermal areas is exploited for hydrogen production. In fact, research advances in this field have concluded that hydrogen sulfide of geothermal resources can contribute significantly and economically in the process of hydrogen generation.The present paper was principally conducted from a literature study and a synthesis of works achieved in recent years in order to highlight the various aspects of hydrogen production from hydrogen sulfide and particularly to study the possibility of the exploitation of Algeria’s thermal resources in this field.     

Hydrogen production as a novel process of wastewater treatment—studies on tofu wastewater with entrapped R. sphaeroides and mutagenesis

Attention is focusing on hydrogen production from wastewater, not only because hydrogen is a clean energy but also because it can be a process for wastewater treatment. In this paper, the characteristics of biological hydrogen production as a process of wastewater treatment is discussed by a comparison with methane production. The hydrogen production from tofu wastewater by anoxygenic phototrophic bacteria and its potential for wastewater treatment are reported. The possibility of co-cultivation with heterotrophic anaerobic bacteria was also investigated. As a solution to overcome the repressive effect of NH₄⁺ on hydrogen production by anoxygenic phototrophic bacteria, a study was done using glutamine auxotroph which was obtained by chemical mutagenesis. To confirm that the mutation had occurred in DNA molecular level, the glutamine synthetase gene was cloned and sequenced.     

Study on Transition Metal Catalysts for Hydrogen Production from Coal Pyrolysis

<正>In this paper,13 kinds of transition metals are studied as catalysts for the hydrogen production from coal pyrolysis, and relationships between the catalytic activity of a transition metal and its outer electron configuration,d% of transition metals and geometric configuration are summarized.Experimental results show that the same group of transition metals show good similarity for hydrogen production from coal pyrolysis;the d%of transition metals which have activity for hydrogen production from coal pyrolysis is between 40%-50%;all transition metals which have catalytic activity possess either a face-centered cubic or a hexagonal crystal structure.Therefore,it is important to choose a transition metal with an appropriate d%and crystal structure as the catalyst for hydrogen production from coal pyrolysis.     

An overview of the IAEA HEEP software and international programmes on hydrogen production using nuclear energy

Recent years have witnessed an increasing interest in hydrogen production using nuclear energy. A number of countries are actively exploring the option of nuclear hydrogen production and have established concrete roadmaps for near and far term achievements. This paper presents a summary of information presented at some IAEA technical meetings on status of nuclear hydrogen production including ongoing related R&D activities in Member States. The paper highlights, in addition, the IAEA hydrogen economic evaluation programme (HEEP) which has recently been developed under agreement and in collaboration with the BHABHA Atomic Research Centre (BARC). HEEP software can be used to perform the economics of the most promising processes for hydrogen production. Current processes considered in HEEP are: high and low temperature electrolysis, thermo-chemical processes including S-I process, conventional electrolysis and steam reforming. HEEP software is also suitable for comparative between nuclear and fossil energy sources, and for solely hydrogen production or cogeneration with electricity. The HEEP modelling includes various aspects of hydrogen economy including storage, transport, and distribution with options to eliminate or include specific details as required by the users.     

Ethanol steam reforming heated up by molten salt CSP: Reactor assessment

In this paper hydrogen production via reforming of ethanol has been studied in a novel hybrid plant consisting in a ethanol reformer and a concentrating solar power (CSP) plant using molten salt as heat carrier fluid. The heat needed for the reforming of ethanol has been supplied to the system by molten salts heated up by solar energy. The molten salt stream temperature drop for supplying hydrogen production process heat duty is less than 20 K, making the molten salt stream still suitable for steam and electricity production in a co-generative plant (clean hydrogen and electricity).     

Value analysis for commercialization of fermentative hydrogen production from biomass

In addition to producing hydrogen gas, biohydrogen production is also used to process wastewater. Therefore, this study specifically conducted value analyses of two different scenarios of fermentative hydrogen production from a biomass system: to increase the value of a wastewater treatment system and to specifically carry out hydrogen production. The analytical results showed that fermentative hydrogen production from a biomass system would increase the value of a wastewater treatment system and make its commercialization more feasible. In contrast, fermentative hydrogen production from a biomass system designed specifically for producing hydrogen gas would have a lower system value, which indicated that it is not yet ready for commercialization. The main obstacle to be overcome in promoting biohydrogen production technology and system application is the lack of sales channels for the system's products such as hydrogen gas and electricity. Thus, in order to realize its commercialization, this paper suggests that governments provide investment subsidies for the use of biohydrogen production technology and establish a buy-back tariff system for fuel cells.     

South African hydrogen infrastructure (HySA infrastructure) for fuel cells and energy storage: Overview of a projects portfolio

The paper provides brief introduction to the National South African Program, branded HySA (Hydrogen South Africa) as well as discusses potential business cases for deployment of hydrogen and fuel cell technology in South Africa. This paper also describes some key activities in the area of hydrogen production and storage within HySA Infrastructure Center of Competence in South Africa. The content of this paper is based on the presentation given during the recent WHEC 2016 Congress in Zaragoza, Spain. More specifically, the discussion of activities at HySA Infrastructure Center of Competence in the paper includes hydrogen production and storage.     

Temporal phenomena of hydrogen photobioproduction

The photobioproduction of hydrogen through in water alga systems has been studied as a suitable way for clean hydrogen generation from renewable solar energy and renewable bio-sources. There is evidence of such hydrogen path metabolism involving some algae types in stress conditions and it has been reported by several authors. In this paper some results of hydrogen production are shown for different stress conditions carried out in not full aseptic environment stabilized by antibiotics, Chlamydomonas reinhardtii has got resistance to. Oscillations and temporal phenomena of hydrogen production have been observed and studied by means of Fourier analysis. Their nature can be related to the variation of hydrogen production rate usually reflected on the cumulative hydrogen curves by the presence of shoulders or accentuated changes of slope.     

Atmospheric pressure microwave plasma source for hydrogen production

Nowadays hydrogen is considered as a clean energy carrier and fuel of the future. That is why the interest in production and storage of hydrogen is still increasing. One of the promising technology is using microwave plasma for hydrogen production. In this study we propose two types of an atmospheric pressure microwave plasma source (MPS) for hydrogen production via methane conversion. The first one was a nozzleless waveguide-supplied coaxial-line-based. The second one was a nozzleless waveguide-supplied metal-cylinder-based. They can be operated with microwave frequency of 2.45 GHz and power up to a few kW with a high gas flow rates (up to several thousands l/h). We present experimental results concerning electrical properties of the MPS, plasma visualization, spectroscopic diagnostics and hydrogen production. The experiment was carried out with methane flow rate up to 12,000 l/h. An additional nitrogen or carbon dioxide swirl flow was used. The absorbed microwave power was up to 5000 W. Our experiments show that MPSs presented in this paper have a high potential for hydrogen production via hydrocarbon conversion.