Hydrogen, sources options

Figure 10.1. Hydrogen production options by energy source (Nitsch, 2002 Pehnt, 2001).

The rest of this chapter examines the current sources of hydrogen and possible future alternatives. Each option raises different questions involving its effects on hydrogen infrastructure options and on the energy and environmental problems we face. Many, if not most, of these questions cannot be answered today, but I will try to answer a number of them in subsequent chapters. 

The Renault Scenic fuel cell vehicle (see the listed web site) has a specially developed high-efficiency squirrel cage induction motor for each road wheel, and is likely to have rivals in competing projects. However, at http //www.sustainability. renault.com/html/image.htm img=images/p/p.jpg, Renault shows a car layout with a front axle driven by one motor. There is a 48 VDC to DC converter followed by a DC to AC inverter. The hydrogen source is a petrol reformer. Evidently the project is still fluid. Setting out the options and alternatives is in hand. 

Table 1.1. Options of Hydrogen (and Syngas) Production Processing regarding Atomic Hydrogen Source, Energy Source for Molecular Hydrogen Production, and Chemical Reaction Processes...

Infrastructure Objective Hydrogen Source Demonstrate H2 fueling station analyze fuel options Primarily trucked in liquid Onsite generation from multiple feedstocks Renewable and fossil fuels Sufficient stations to provide consumer convenience Most cost effective sources by region Investment for substantial number of aR stations to be H2 capable... 

A fuel gas long situation also provides the opportunity to recover valuable products from the fuel gas. For example, a refinery plant might consider recovery of hydrogen from a hydroprocessing gas source. Options for H2 recovery include pressure swing adsorption (PSA) and membrane systems based on the H2 purity requirement. Alternatively, ethane and ethylene could be recovered from certain fuel... 

Orhana, M. F., Dincer, I., Rosen, M. A., Kanoglu, M. (2012). Integrated hydrogen production options based on renewable and nuclear energy sources. Renewable Sustainable Energy Reviews, 16, 6059—6082. 

Eig. 1. The key steps for the Phillips PPS process are (/) production of aqueous sodium sulfide from aqueous sodium hydrogen sulfide (or hydrogen sulfide) and aqueous sodium hydroxide 2) dehydration of the aqueous sodium sulfide and NMP feedstocks 5) polymerization of the dehydrated sulfur source with -dichlorobenzene to yield a slurry of PPS and by-product sodium chloride in the solvent (4) polymer recovery (5) polymer washing for the removal of by-product salt and residual solvent (6) polymer drying (7) optional curing, depending on the appHcation and (< ) packaging. 

It is important to produce HCl rather than elemental chlorine, CI2, because HCl can be easily scmbbed out of the exhaust stream, whereas CI2 is very difficult to scmb from the reactor off-gas. If the halogenated hydrocarbon is deficient in hydrogen relative to that needed to produce HCl, low levels of water vapor may be needed in the entering stream (45) and an optional water injector may be utilized. For example, trichloroethylene [79-01 -6] C2HCI2, and carbon tetrachloride require some water vapor as a source of hydrogen (45). 

Demirbas, M. F., Technological options for producing hydrogen from renewable resources. Energy Sources, Part A Recovery, Utilization, and Environmental Effects 2006, 28(13), 1215-1223. 

In the renewable scenario, 50% of the hydrogen must come from renewable sources from 2020 on. Biomass is the cheapest renewable option, but has a limited potential, as the competition between hydrogen, biofuels and other uses has to be considered. Offshore wind via electrolysis could, therefore, play a very important role for hydrogen production after 2020. Onsite SMR also dominates here in the early phase. 

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