Hydrogen from Natural Gas and Coal

Dry reforming (Eq. 7.9) has been studied in combination with and without oxygen addition [35, 64, 80, 81] employing Ru, Rh and Ni-based catalysts. Generally, an improved 

For example, for a composite membrane of 1 mm outer diameter, feed space velocity of 24,000, and 4-pm-thick Pd membrane, about 122 g Pd is needed for sustaining the 

50kWg fuel cell. And, for a 1-pm-thick Pd membrane on a 1 mm fibre, a required fuel 

More recent experimental studies comparing traditional packed-bed [105] and fluidized bed [106] reactors with Pd-based membrane reactors in methanol steam reforming show that the latter gives better performance. CO selectivity decreases with increasing pressure due to hydrogen removal [105], which also improves methanol conversion. This is exemplified by complete methanol conversion obtained at 300 C in the membrane reactor, while under similar conditions an FBR reaches only 55% [106]. 

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Robert Williams, Eric Larson, Ryan Katofsky, and Jeff Chen, Methanol and Hydrogen from Biomass for Transportation, with Comparisons to Methanol and Hydrogen from Natural Gas and Coal, report 292, Center for Energy and Environmental Studies, School of Engineering and Applied Science, Princeton University, 1995. 

DOE Hydrogen from Natural Gas and Coal , Hydrogen Coordination Group, DOE (June 2003) (Section 2.2.1)... 

Estimated Carbon Emissions as Carbon Dioxide Associated with Central Station Hydrogen Production from Natural Gas and Coal, 85... 

The chapter begins with a description of reference processes that are currently used industrially for hydrogen production and power generation from natural gas and coal. Alternative plant designs that employ membranes are discussed next. Only oxygen and hydrogen separation membranes are... 

Synthesis gas, a mixture of carbon monoxide and hydrogen, can be derived from natural gas and coal. 

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). 

Today, different processes (steam reforming, autothermal reforming, partial oxidation, gasification) are available and commercially mature for hydrogen production from natural gas or coal. These processes would have to be combined with technologies for C02 capture and storage (CCS), to keep the emissions profile low. A power plant that combines electricity and hydrogen production can be more efficient than retrofitted C02 separation systems for conventional power plants. 

In general terms, it is expected that decarbonizing hydrogen made from natural gas or coal will increase the production cost by between 50 and 75%. Hydrogen gas that is produced conventionally (with CO emitted to atmosphere) costs about twice as much as natural gas or oil and about three times more than coal. 

Methanol, also called methyl alcohol and once commonly know as wood alcohol, is a clear, volatile liquid mp, -98°C bp, 65°C). Until the early 1900s, the major commercial source of methanol was the destructive distillation (pyrolysis) of wood, a process that yields a product contaminated with allyl alcohol, acetone, and acetic acid. Now methanol is synthesized by the following reaction of hydrogen gas and carbon monoxide, both readily obtained from natural gas or coal gasification ... 

It should be noted that prior to 1950, substantial quantities of hydrogen mixed with CO were produced from coal and distributed in cities as town gas. Some cities in the world still distribute a 50% by volume mixture of H2 with CO in city distribution systems. Currently, hydrogen is an industrial commodity, derived primarily from natural gas and the technology for handling it is familiar to industry. 

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