Hydrogen by electrolysis

Westinghouse A proposed thermochemical process for decomposing water to oxygen and hydrogen by electrolysis, coupled with the high-temperature decomposition of sulfuric acid ... 

Almost a billion metric tons of C02 are sequestered in 2025. Then, hydrogen is produced from coal, oil and gas fields, with the carbon dioxide extracted and sequestered cheaply at the source. Large-scale renewable sources and nuclear energy are producing hydrogen by electrolysis come 2030. 

Chapman EA (1965) Production of hydrogen by electrolysis. Chem Process Eng 46 387-393... 

Iceland escapes this dilemma because most of their energy is from clean sources, hydropower and geothermal, rather than from hydrocarbon combustion. Since there are few emissions in the production of their electricity, providing hydrogen by electrolysis does not spoil the zero-emission advantage for Iceland s fuel cells. 

The simplest kind of cell construction, shown in Figure 19.19(d), suffices for the production of hydrogen by electrolysis of water and for the recovery of chlorine from waste HC1. The term filter-press cell is applied to this kind of equipment because of the layered construction. These two electrolyses are economically feasible under some conditions. Some details are given by Hine (1985). 

If the successful bidder is a PV supplier, some of the DC electricity will be directly used to generate hydrogen by electrolysis. This would not only save the cost of DC-to-AC conversion, but also would lower the cost of energy transportation because it costs less to transport LH2 than electricity. 

Fuel boxes can be distributed like soft drinks to multiple distribution channels, even dispensing machines. Consumers can get their fuel anywhere and any time. By 2025, one-quarter of the industrialized vehicle fleet uses fuel cells, which also account for half of new sales. Renewables start out slowly but pick up speed after 2025. Some one billion metric tons of co2 are sequestered in 2025, and, after 2025, hydrogen is widely produced from coal, oil and gas fields, with carbon dioxide extracted and sequestered cheaply at the source. Also, large-scale renewable and nuclear energy schemes to produce hydrogen by electrolysis become attractive by 2030. ... 

Our preliminary economic analysis of the chemical hydride slurry cycle indicates that hydrogen can be produced for 3.65/GJ ( 3.85/MMBtu) based on a carbon cost of 1.35/GJ ( 1.42/MMBtu) and a plant sized to serve a million cars per day. This compares to current costs of approximately 5.75/GJ ( 6.06/MMBtu) to produce hydrogen from 2.85/GJ ( 3.00/MMBtu) natural gas, and 24.50/GJ ( 25.83/MMBtu) to produce hydrogen by electrolysis from 0.05 per kWh electricity. The present standard for production of hydrogen from renewable energy is photovoltaic-electrolysis at 41.80/GJ ( 44.07/MMBtu). Costs have been derived from Padro (1999). 

Figure 11. Effect of by-product credits on hydrogen price for 100 X 106 scfd of hydrogen by electrolysis and steam-iron processes...

Morizonoa, T., Watanabe, K., and Ohstsuka, K., Production of hydrogen by electrolysis with proton exchange membrane (PEM) using sea water and fundamental study of hybrid system with PV-ED-EC, Mem. Fac. Eng., 31, 213-218 (2002). 

First, in this scenario solar or wind power-operated water electrolyzers are included. These energy sources deliver their power discontinuously. So, the electrolyzers must be able to tolerate fluctuating loads, a goal to be achieved in present developments. Second, this economy includes the conversion of electricity to hydrogen by electrolysis and from hydrogen back to electricity via fuel cells. So, the efficiency of this sequence has to be taken into account when looking at the chances. 

Industrial electrolyzers use electrodes and gas collection schemes optimized to produce the maximum amount of hydrogen using the minimum size equipment and minimum quantity of electric energy. Their basic principle of operation is an extension of the simple process described above. Equipment for the industrial scale production of hydrogen by electrolysis is available from a number of manufacturers. Some of these are ... 

Plant operating costs for the production of hydrogen by electrolysis and by propane reforming are compared in Table 10-3 for various sizes of... 

For small hydrogen requirements it is possible to economically reform methanol especially if there is a low cost supply of methanol by-product available. This is an economical alternative to liquid hydrogen purchase or generation of gaseous hydrogen by electrolysis of water for quantities in the range of 100-2000 N mVh (3500-7000 SCF/h). The process developed by... 

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