ОңТҮстік қазақстан медицина академиясы, хабаршы №4 942, 2021 жыл, том 2
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- Бұл бет үшін навигация:
- Electrolysis
- Steam-Methane Reformation
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BIOHYDROGEN PRODUCTION Hydrogen is the most abundant element in the Universe and very common on earth. Its atomic structure is the simplest of all atoms, since it is composed of one proton and one electron. Usually, pure hydrogen, which is diatomic (H 2 ), does not exist naturally since it easily combines with other elements. Hydrogen is mainly chemically bound in water, biomass or fossil fuels. In order to get hydrogen into a useful form, it must be extracted from one of these substances. This process requires energy. Accordingly, the cleanliness and renewability of this energy is of critical importance. While hydrogen fuel cells operate without producing emissions, making hydrogen can produce significant greenhouse gases and other harmful byproducts. Nevertheless, once obtained, hydrogen is a nearly ideal energy carrier. There exist various ways for hydrogen processing which are briefly described below although hydrogen from biomass is focused in this handbook: Electrolysis : Water electrolysis involves passing an electric current through H 2 O to separate it into hydrogen (H 2 ) and oxygen (O 2 ). Hydrogen gas rises from the negative cathode and oxygen gas collects at the positive anode. Electrolysis produces extremely pure hydrogen, but a large amount of electricity is required. Ideally, this would come from renewable sources like wind and photovoltaic. Steam-Methane Reformation : Hydrogen can be reformed from natural gas by a two-step process at temperatures reaching 1100 °C in the presence of a catalyst. This is a relatively efficient and inexpensive process, especially in case of cogeneration. Photoelectrolysis : Photoelectrolysis uses sunlight to split water into its components via a semi-conducting material. It is roughly like immersing a photovoltaic cell in water, whereby the incoming light stimulates the semiconductor to split H 2 O directly into its constituent gases. Though promising, this is still an experimental method of hydrogen production that has not evolved beyond the laboratory. жүктеу/скачать 3,39 Mb. Достарыңызбен бөлісу:
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