Process Analysis and Simulation of the Solar Thermo-Chemical Hydrogen Generation (original) (raw)

HYDROGEN ENERGY: THE GOOD, THE BAD, AND THE ENVIRONMENTALLY ACCEFTABLE

Hydrogen is in many respects the ultimate fuel: it is the most abundant element in the universe; as a molecular species it possesses the highest gravimetric energy density of any chemical substance; it can be burned cleanly to produce only water as a reaction product; and its simple and rapid electrode kinetics open the possibility of high efficiency fce! cell-drivon power trains. On the otl1t.r hand, as a gaseous substance under standard conditions, it is inconvenient to use as an on-board fuel without severe compromises with respect to distance between refueling stops; rapid rates of effusion and wide combustibility range limits give rise to safety concerns; and finally, under terrestrial conditions, Hz is seldom found in Nature-it must be. derived from other compounds, often at considerable expense. The various aspects of hydrogen energy combine to paint a picture that is compelling but also technologically challenging.

HYDROGEN FOR A SUSTAINABLE ENERGY SYSTEM: A REVIEW

Journal of Research in Engineering and Applied Sciences, 2017

In this paper, we will try to shed some light on how to overcome the two challenging problems the world has been facing regarding energy, by using hydrogen for a sustainable energy system. These two main problems are: 1st: Fossil fuels,which meet about 80 % of our energy needs today, are being depleted fast. 2nd: The use of fossil fuels is causing major environmental problems. Solution of these interrelated problems has been pursued through the use of what is called Sustainable Energy Resources (SER). Hydrogen is introduced as an energy carrier to utilize SER in an effective and non-polluting way. The analogy between hydrogen and blood circulation as energy carriers is established in this investigation; where hydrogen provides energy in an energy system while blood transports nutrients, and oxygen in human body to provide nourishment. Methods of hydrogen production have been presented. The pros and cons of using hydrogen in our system are illustrated. Data on the overall efficiency of conversion of solar energy to produce hydrogen using different options are cited with illustrations.

Hydrogen Energy: An Alternative Fuel for the Future

Central Asian Journal of Theoretical and Applied Science, 2022

Hydrogen is an energy carrier that can transform our fossil-fuel dependent economy into a hydrogen economy, which can provide an emissions-free transportation fuel. Literature reviews and independent research were the main methods of research. Hydrogen storage and transport are issues of intense research due to hydrogen’s characteristic low density. Hydrogen is the fuel of the future. As an avid researcher of alternative fuels and an ambitious chemistry student, this researcher understands the importance of a shift to a hydrogen economy. Hydrogen is an energy carrier that can be used in internal combustion engines or fuel cells producing virtually no greenhouse gas emissions when combusted with oxygen. The only significant emission is water vapor. Hydrogen production and storage is currently undergoing extensive research. A solar-hydrogen system can provide the means of a totally emissions-free method of producing hydrogen. Although steam reformation of methane is currently the major route to hydrogen production, the emissions involved can also be controlled much more efficiently than our current system of transportation fuel. Much work is in progress to initiate a shift from a fossil-fuel economy to a hydrogen economy.

An Overview of Hydrogen as an Alternative Fuel

MDPI, 2020

Hydrogen is a very important fuel of our secure and clean energy future. Hydrogen will be the fuel of the future and gradually it will replace all current fossil fuels. Hydrogen can be used as a fuel for vehicles, to heat homes and offices, to produce electricity, and to fuel ships and aircraft. The present work provides an overview of hydrogen as an alternative fuel, which can be used in internal combustion engines and in fuel cells.

The hydrogen option for energy: A review of technical, environmental and economic aspects

International Journal of Hydrogen Energy, 1995

Hydrogen, within technical spheres, has not yet obtained, generally, sound validity as an integrating fuel. Apart from the cost of production, the main reason seems to be a safety problem. In the present article, the author tries to contribute to the "cause" of this excellent element, as a wholly non-polluting fuel and an acceptably reliable one. The article is divided into five parts. The first is concerned with CO, production by combustion throughout the planet, and its effect on the earth's temperature. The second part is a comparative technical and environmental outline of different kinds of fuel: methane, pit-coal, gasoline, hydrogen. Thirdly, some quahtative indices are defined: pollution, flammability, expansion or explosivity index. In the fourth part the stages of a solar-hydrogen cycle are presented. The final part treats the economic aspects, and offers a comparative survey of the above-mentioned fuels.

HYDROGEN A SOURCE OF ALTERNATE FUEL

International Journal of Emerging Technologies and Innovative Research, 2018

Energy price is rising due to rapid depletion of fossil fuels. Development of renewable and non-polluting energy resources is necessary for reducing pollution level caused by those conventional fuels. Researchers have recognized hydrogen (H2) as such an energy source. Hydrogen is a potential non-carbon based energy resource, which can replace fossil fuels. Hydrogen is considered as the alternative fuel as it could be generated from clean and green sources. Despite many advantages, storage of hydrogen is a serious problem. Due to high inflammability, adequate safety measures should be taken during the production, storage, and use of H2 fuel. This review article elucidates production methods and storage of hydrogen.

Hydrogen as the Future Sustainable Energy – A Review

2011

Nowadays, worldwide faces problems caused by fossil fuels such as urban air pollution and climate change. Hence, alternative energy sources are being searched in order to replace the fossil fuels. One of these alternative energy sources is coming from hydrogen. Hydrogen is the simplest and most abundant element in the universe and as a matter of fact hydrogen can be produced in variety of ways, including electrolysis of water, thermo catalytic reformation of hydrogen-rich organic compounds, and biological processes. This paper discussed mainly on the way of hydrogen being produced, its economic and environmental impacts to the society. Alternative sources of producing hydrogen as opposed to conventional method were also discussed.

Hydrogen Energy: An Innovative Advancement for Energy and Environment

The economic development of countries with increasing energy needs, the depletion of the fossil fuels, world competition and volatility of prices, the struggle at ensuring the security of supply, concerns about emissions of greenhouse gases, rapid climate change and the reluctance of people to change their behaviour put energy as top priority among the most important and difficult problems before the countries in today's world.

Hydrogen as energy source to avoid environmental pollution

El hidrógeno como energético para el futuro fue propuesto hacia fines de los años setenta. La razón principal fue la crisis petrolera, la cual llevó a considerar la necesidad de la substitución de los hidrocarburos por fuentes alternas de energía. El hidrógeno como fuente de energía, no sólo es el elemento más abundante en el universo, también es muy común en la Tierra. Es la fuente de energía alterna más importante para la creciente demanda energética y la respuesta para la necesidad actual de una energía limpia, eficiente y tecnológicamente amigable con el ambiente. Al quemar hidrógeno se produce agua y óxidos nitrosos, los cuales pueden ser eliminados utilizando celdas de combustible. Una celda de combustible es un sistema electroquímico que genera electricidad en una forma silenciosa y eficiente. Si a partir de una fuente de energía primaria que no produzca CO 2 , como la solar, eólica o nuclear, se obtiene el hidrógeno, durante la generación de la energía se puede evitar la contribución al efecto invernadero y la lluvia ácida. El hidrógeno puede también ser utilizado como un portador de energía. Se presenta el estado del arte en investigación y desarrollo del uso del hidrógeno en México y en el mundo.

Hydrogen as Fuel and Its Impacts on Environment

Journal of agricultural science & technology A, 2018

Energy consumption per capita is a kind of indication of the development for a society. Energy sources, today, are mainly fossil fuels (coal, oil and natural gas) which can cause severe environmental problems such as acid rains, global warming and climate changes. In addition to severe environmental problems, the sources of fossil fuels are finite. Because of increasing need of energy, researchers are forced to search for renewable energy sources such as hydro, biomass, wind, solar, geothermal, wave, tide and so on. Hydrogen (H 2) seems to be more promising for a clean energy source. In fact, it is a clean energy carrier with a role to save environment. It does also reduce the emission of greenhouse gases by using it as a fuel in fuel cells or in internal combustion engines directly. For usage of H 2 as fuel, it is necessary either to compress or to liquefy it. Both processes are difficult and costly. Metallic and nonmetallic hydrides have received considerable research interest in recent years. NaBH 4 is the one of the most prospective H 2 storage materials as it stores 10.8 weight % hydrogen. H 2 is generated by hydrolysis reaction of NaBH 4 in the presence of a suitable catalyst. Another important fact with fuel cells is that the 2nd law of thermodynamics is bypassed so that no thermal efficiency limitations are imposed. In this paper, adverse effects of fossil fuels and positive effects of fuel cells on environment are emphasized.