BIOMASS TO H2
Originally posted by russ_watters
Joe touches on this: without first converting the entire electric power grid to renewable energy (then expanding it to meet the new load), it must be assumed that hydrogen will be manufactured using existing generation capacity and/or technology. Since virtually all new electric generation capacity is fossil fuel (gas turbine), virtually all of the energy used to manufacture the hydrogen would just be re-directed fossil fuel energy.
This idea of converting the electrical infrastructure is not the solution. This again is thinking in terms of a tiered distribution system. However, before getting into this more deeply, I will list some of the science being done for various methods of H2 production. Let me know when you have calculated to complete energy cost per gallon for gasoline. I am assuming that thus far, no one knows this answer. Nonetheless, I will begin to account for these energy costs for H2. Of course a full energy accounting for gasoline will also be needed for comparison.
Here are a few excerpts from the biomass approach to H2 production. Please note the 80-90% yields.
http://www.eere.energy.gov/hydrogenandfuelcells/hydrogen/iea/pdfs/hydrogen_biomass.pdf
State of the Art and Research Challenges
Thomas A. Milne, Carolyn C. Elam and Robert J. Evans
National Renewable Energy Laboratory
Golden, CO USA
A Report for the International Energy Agency
Agreement on the Production and Utilization of Hydrogen
Task 16, Hydrogen from Carbon-Containing Materials
DIRECT PRODUCTION FROM WHOLE BIOMASS
Gasification
Thermal/Steam/Partial Oxidation
This section briefly covers processes that will be addressed in detail in a new cooperative Task of the IEA Bioenergy Agreement. It is included here for completeness of the survey under the IEA Hydrogen Agreement Task 16, Hydrogen from Carbon-Containing Materials. [Dr. Suresh Babu (USA) at the Gas Technology Institute can be contacted for details of the IEA Bioenergy Agreement.s gasification-to-hydrogen plans.] Consideration of hydrogen from carbonaceous materials has a long history in the .hydrogen. literature. At the First World Hydrogen Energy Conference, Tsaros et al. (1976) (USA) reported on three routes to hydrogen using sub-bituminous coal. (Their ultimate goal was liquid fuels.) The processes considered were: (1) Koppers-Totzek; (2) U-Gas and (3) Steam-iron. Hydrogen yields of 93-96% of theoretical were predicted. Soo et al. (1978) (USA) present calculations and experimental data on steam processes to convert coal to hydrogen. A large excess of steam (4 moles water to 1 mole carbon) at 1300°C produces up to 90% hydrogen without the need for shift conversion. It was claimed that their process is a better source of hydrogen than Hygas or Steam-iron. Eliminating the need for pure oxygen renders this process superior to the large, Totzek and Synthane processes.
A technical note by Williams (1980) (USA) makes a case for efficient hydrogen production from coal using centrifuge separation of hydrogen from other gases following steam gasification at 1100-5000°C. Recent advances in new materials developed by the aerospace industry made it appear possible to develop such a gaseous centrifuge. The U-Gas® process for producing hydrogen from coal is discussed by Dihu and Patel (1983) (USA). U-Gas® has been developed by IGT from over 50 years of coalconversion research. It comprises a single-stage, non-slagging, fluidized-bed gasifier using oxygen or air. Pilot plant results and economic projections of the cost of hydrogen are given. Pilot-scale experiments in the steam gasification of charred cellulosic waste material are discussed in Rabah and Eddighidy (1986) (Egypt). The beneficial effects of some inorganic salts, such as chlorides, carbonates and chromates, on the reaction rate and production cost of hydrogen were investigated.
A large number of single research studies have appeared from 1981-2000, from researchers in many countries around the world. Brief notes follow. McDonald et al. (1981) (New Zealand) proposed extracting protein from grass and lucern and using the residue for hydrogen production (among other fuels). Saha et al. (1982, 1984) (India) reported using a laboratory-scale fluidized-bed autothermal gasifier to gasify carbonaceous materials in steam. Further studies with agricultural wastes were planned. Cocco and Costantinides (1998) (Italy) describe the pyrolysis-gasification of biomass to hydrogen. More-or-less conventional gasification of biomass and wastes has been employed with the goal of maximizing hydrogen production. Researchers at the Energy and Environmental Research Center at Grand Forks have studied biomass and coal catalytic gasification for hydrogen and methane (Hauserman & Timpe, 1992, and Hauserman...
PRODUCTION OF STORABLE INTERMEDIATES FROM BIOMASS PARTIAL CONVERSION
Hydrogen from Biomass-Derived Pyrolysis Oils Laboratory work using this approach has been conducted at NREL (USA), starting in 1993 (see Chornet et al., 1994; Wang et al., 1994; Wang et al., 1995; Chornet et al., 1995; and Chornet et al., 1996 a, b, c). Early papers present the concept of fast pyrolysis for converting biomass and wastes to oxygenated oils. These oils are subsequently cracked and steam-reformed to yield hydrogen and CO as final products (Mann et al., 1994). The 1995 Wang report presents the chemical and thermodynamic basis of this approach, the catalysis related to steam reforming of the oxygenates, and the techoeconomic integration of the process. In first experiments, Nibased catalysts were favorable (80% of theoretical maximum hydrogen yield has been obtained), but enough CO remained to require the addition of a water-gas shift step. Low biomass costs are needed to produce hydrogen economically since feedstock cost is a major component of production cost. In Wang et al. (1995) laboratory and bench-scale studies of model compounds of oxygenates known to be present in pyrolysis oil were presented. Ni-based catalysts were used in microscale laboratory tests to identify the conversion products. All model compounds were successfully steam reformed. Bench-scale, fixed-bed tubular reactor experiments indicate that control of coke formation was a key aspect of the process. Loss of activity of the nickel catalysts after a few hours forced periodic regeneration. It was shown that
CO2 from a pressure swing absorption step effectively removed the coke.
Six progress reports in 1996 and 1997 document the systematic exploration of the pyrolysis oilto-hydrogen process. In Chornet et al. (1996a) bench-scale experiments determined the performance of nickel-catalysts in steam reforming of acetic acid, hydroxyacetaldehyde, furfural, and syringol. All proceeded rapidly. Time-on-stream experiments were started. In Chornet et al., (1996b), Czernik et al., (1996), and Wang et al. (1997a), the approach of using extractable, valuable co-products with the balance of the oil converted to hydrogen is explored. Depending on biomass feedstock costs, the selling price for steam reforming hydrogen is predicted to fall within the then current market price of hydrogen ($5-$15/GJ). One of the most promising coproducts from whole bio-oil is an adhesive. In Chornet et al., (1996c) economics and plant design are summarized. The initial refereed journal reports of the above work are in Wang et al. (1996), and Wang et al. (1997b). The first paper documents the catalytic steam reforming results for acetic acid and hydroxyacetaldehyde using a micro-reactor and molecular-beam mass spectrometry. The second paper consolidates the early work on model compounds, nickel-catalysts and reforming of both whole bio-oils and oils after extraction of valuable chemicals. Economics, process designs and thermodynamics are discussed. In 1998, the NREL group published data on bench-scale reforming results from model compounds, the aqueous-fraction of poplar pyrolysis oil and whole pyrolysis oil with commercial nickel-based steam reforming catalysts. Hydrogen yields as high as 85% were obtained .
