Helo Bear K very good relevant literature work
On Wed, Dec 29, 2010 at 7:13 PM, Bear Kaufmann <[email protected]>wrote: > I looked through some of the papers I have on hand, and extracted the > interesting parts as they relate to the latest discussion, FWIW: > > "Fuel gas can be used directly as fuel in gas burners or internal > combustion engines and gas turbines. Fuel gas, after purification and > possibly water gas shift to adjust the H2/CO ratio, can be described as a > syngas (a mixture of H2 and CO), which can be used to manufacture methanol, > ammonia, Fischer Tropsch liquids, or hydrogen for use in fuel cells (4). The > suitability for a particular usage, i.e. the fuel gas quality, is determined > by the gas composition and the level of contamination by particulates, > alkali compounds, nitrogen-containing components, sulphur and tars (5)." > from Kalisz, S. et al. Energy Balance of High Temperature Air/Steam > Gasification of Biomass in Up-Draft, Fixed-Bed Type Gasifier. Int. Conf. on > Incineration and Thermal Treatment Technologies, Phoenix, Arizona (2004).at > <http://gasunie.eldoc.ub.rug.nl/FILES/root/2004/3265200/3265200.pdf> > > "Fast pyrolyzers rapidly (∼1 s) heat dry biomass (10% H2O) to ∼500°C and > thereby thermally transform biomass into bio-oil (∼60% of mass), syngas > (∼20% of mass), and charcoal (∼20% of mass). The energy required to operate > a fast pyrolyzer is ∼15% of the total energy that can be derived from the > dry biomass. Modern systems are designed to use the syngas generated by the > pyro- lyzer to provide all the energy needs of the pyrolyzer." > from Laird, D.A. The Charcoal Vision: A Win Win Win Scenario for > Simultaneously Producing Bioenergy, Permanently Sequestering Carbon, while > Improving Soil and Water Quality. Agron J 100, 178-181(2008). > > "To improve the thermal efficiency and predict the composition of syngas, > several numeric models have been developed for biomass conversion systems." > from Rogel, A. & Aguillón, J. The 2D Eulerian Approach of Entrained Flow > and Temperature in a Biomass Stratified Downdraft Gasifier. American Journal > of Applied Sciences 3, 2068-2075(2006). > Comments: Shows a stratified downdraft model with inputs of air and > biomass, outputs of syngas and ashes > > "The term ‘pyrolysis’ is typically used either for ...[analytical > purposes]... or for bioenergy systems that capture the off-gases emitted > during charring and used to produce hydrogen, syngas, bio-oils, heat or > electricity (Bridgwater et al, 1999)." > from Lehmann, J. & Joseph, S. Biochar for environmental management: science > and technology. (Earthscan/James & James: 2009). > > "High purity syngas (i.e. low quantities of inerts such as N2) is extremely > beneficial for fuels and chemicals synthesis since it substantially reduces > the size and cost of downstream equipment. However, the guidelines provided > in Table 5 should not be interpreted as stringent requirements. " > "There is more latitude with regard to syngas composition for engine > combustion than for turbine combustion." > "To be considered interchangeable with conventional fossil fuels (natural > gas or distillate oils) and to ensure maximum flexibility for industrial or > utility applications, syngas heating value needs to be above 11 MJ/m3" > "At temperatures greater than 1200-1300oC, little or no methane, higher > hydrocarbons or tar is formed, and H2 and CO production is maximized without > requiring a further conversion step." > "Biomass gasification is the conversion of an organic...carbonaceous > feedstock by partial oxidation into a gaseous product, synthesis gas or > “syngas,” consisting primarily of [H2 and CO] with lesser amounts of [CO2, > CH4], higher hydrocarbons (C2+), and nitrogen (N2). The reactions are > carried out at elevated temperatures, 500-1400oC, and atmospheric or > elevated pressures up to 33 bar (480 psia). The oxidant used can be air, > pure oxygen, steam or a mixture of these gases. Air-based gasifiers > typically produce a product gas containing a relatively high concentration > of nitrogen with a low heating value between 4 and 6 MJ/m3 (107-161 > Btu/ft3). Oxygen and steam-based gasifiers produce a product gas containing > a relatively high concentration of hydrogen and CO with a heating value > between 10 and 20 MJ/m3 (268-537 Btu/ft3)." > "Table 8. Compositions of Biomass-Derived Syngas" - includes N2 from 0-56%, > H2 from 5-43.3%, CO from 9-67%, CO2 from 4-40% > ... > from Ciferno, J.P. & Marano, J.J. Benchmarking biomass gasification > technologies for fuels, chemicals and hydrogen production. US Dep of Energy > NETL (2002).at < > http://seca.doe.gov/technologies/coalpower/gasification/pubs/pdf/BMassGasFinal.pdf > > > > "The resulting fuel is a producer gas (a synthesis gas or syngas) that > consists primarily of varying ratios of hydrogen and carbon monoxide (CO)." > from Mukhtar, S. Manure to Energy: Understanding Processes, Principles and > Jargon. (2006).at < > http://repository.tamu.edu/bitstream/handle/1969.1/87462/pdf_2425.pdf?sequence=1 > > > > In short, the usage from the above doesn't appear entirely clear. > But in general, syngas is often suggested to have been upgraded, or of a > higher CO/H2/energy content. Syngas is often used to refer to gas intended > to be used for synthesis of products. Syngas does also seem to be used as > general term in some cases. > > My preferred usage has been to call the gas the air-blown GEK makes > "producer gas". Wood gas notes that the carbon source was biomass, though I > don't prefer the term. "Syngas" being made with O2 or steam. > The problem with the above is it doesn't leave a general catch-all term. > > Cheers, > Bear Kaufmann > All Power Labs > > _______________________________________________ > The Gasification list has moved to > [email protected] - please update your email contacts to > reflect the change. > Please visit http://info.bioenergylists.org for more news on the list > move. > Thank you, > Gasification Administrator your truely -- ************************************************ P.V.PANNIRSELVAM ASSOCIATE . PROF. Research Group ,GPEC, Coordinator Computer aided Cost engineering DEQ – Departamento de Engenharia Química CT – Centro de Tecnologia / UFRN, Lagoa Nova – Natal/RN Campus Universitário. 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