| 摘要 |
Hydrogen is a secondary energy carrier for renewable energies. Hydrogen is usually produced by electrolysis of water to store electrical energy. In a fuel cell, the hydrogen can be converted back into electrical energy. The natural gas network is suitable for storing hydrogen. Owing to the great physical and combustive differences between natural gas and hydrogen, the accommodation of the latter in the gas network is very restricted. The invention relates to a method by which hydrogen originating from electrolysis is reacted with synthesis gas to form methane, and the methane is introduced into the gas network. The introduced methane or the equivalent thereof in natural gas is withdrawn from the gas network and converted back into hydrogen and carbon dioxide in a reformer. To form 1 mole of methane, 2 mol of hydrogen from the electrolysis must be added to the synthesis gas. When the methane is decomposed again, twice the amount of hydrogen, 4 mol, is obtained. The synthesis gas can be obtained from biomass, e.g. wood, coal, or carbon compounds. A preferred method is to react the carbon dioxide that is formed in the reformer and hydrogen with an equimolar amount of fresh methane/natural gas. This produces a particularly economical and pure synthesis gas. The carbon dioxide is circulated and does not pass into the environment. The secondary energy carrier, hydrogen, is stored and distributed in the natural gas network as methane, similar to natural gas, is doubled in quantity when withdrawn, and is supplied as hydrogen to fuel cells for conversion back into electricity. |
