Hydrogen production process

Today the two most common methods used to produce hydrogen are (1) steam reforming of natural gas, and (2) electrolysis of water. The predominant method for producing synthesis gas is steam reforming of natural gas, although other hydrocarbons can be used as feedstocks. For example, hydrogen can be produced from the biomass reforming process. 

CHj is a very stable molecule and has to be processed under very severe conditions. Although its conversion to synthesis gas can be conducted at temperatures even below 700 K, high yields to syngas need substantially higher temperatures, typically 1100 K. The reaction products H, CO, and H O are for all practical purposes stable at reaction conditions. 

Hydrogen production by catalytic steam reforming and partial oxidation of hydrocarbons has been the most efficient, economically and widely used process for the 

A desulfurized hydrocarbon is mixed with process steam over a nickel-based catalyst in the reformer, where the endothermic reforming reaction occurs at 1175 K  

The synthesis gas enters the shift converter, where the exothermic water-gas shift reaction occurs at 475 to 675 K as follows  

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Recently, fuel cells have commanded attention to establish high-effidency hydrogen production process. Some catalytic processes have been considered, but they have typically entailed numerous problems (high temperatures, catalyst deactitmtion, and coking). 

Low energy pulsed (LEP) discharge is a simple hydrogen production process. This novel technique requires neither high temperature nor pressure die reaction takes place at room temperature and atmospheric pressure. We have successftilly reformed hydrocarbons using this LEP dischai e [1-6]. 

Slow pyrolysis, also called carbonization, is characterized by a high charcoal yield and is not considered for hydrogen production processes. The slow pyrolysis of wood (24 h typical residence time) was a common industrial technology to produce charcoal, acetic acid, methanol, and ethanol from wood until the early 1900s. 

Hydrogen production process by direct photolysis of hydrogen-containing compounds may be based on different types of photosensitizers in parallel with inorganic semiconductors. The model systems for photoinduced hydrogen production with porphyrins and hydrogenase were developed [4],... 

Small-scale (fossil-based) hydrogen production processes, 13 844 Small-signal value, 14 666 Small water-soluble molecules in hemodialysis, 26 820-821 Smaltite, 7 209t Smart emulsions, 10 131 Smart pills, 24 61-62... 

The (additional) costs of C02 capture in connection with hydrogen production from natural gas or coal are mainly the costs for C02 drying and compression, as the hydrogen production process necessitates a separation of C02 and hydrogen anyway (even if the C02 is not captured). Total investments increase by about 5%-10% for coal gasification plants and 20%-35% for large steam-methane reformers (see also Chapter 10). 

Cormos, C. C., Starr, F., Tzimas, E. and Peteves, S. (2008). Innovative concepts for hydrogen production processes based on coal gasification with C02 capture. International Journal of Hydrogen Energy, 33 (4), 1286-1294. 

Steam methane reforming (SMR) is the most widely practiced commercial process for the production of syngas and hydrogen almost 50% of the world s hydrogen production comes from natural gas. Two equilibrium reactions, steam reforming and the water-gas shift (WGS) reaction, are at the heart of the hydrogen production process ... 

Balaf M., Ozdemir, N. 2005. New and renewable hydrogen production processes. Energy Sources 27 1285-1298. 

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