[Gasification] Syn Gas

Thu Dec 30 20:44:29 CST 2010

Very well explained and I am in full agreement with all the definitions.

On Fri, Dec 31, 2010 at 3:24 AM, <JBlack9999 at aol.com> wrote:

> Like many of you, I have been in the chemical industry for many  years.
> It has been my experience that a gas became synthesis gas or  syn-gas after
> various treatment processes to prepare it to synthesize a  particular
> chemical.   Prior to preparing it for synthesizing it had  other names.
>
> Typically in the chemical/petrochemical industry it was prepared by
> reforming natural gas.   After reforming, it was called reformed  gas.
> Subsequently, the ratio of hydrogen to carbon monoxide was  adjusted
> (shifted) to the
> proper value for the particular product that was  being synthesized.  That
> gas was called shift gas.   The  next stage was to remove carbon dioxide.
> At that stage the gas was called  syngas, because it was then ready to be
> synthesized into the final  product.
>
> In general terms, to synthesize methanol the ratio of hydrogen to carbon
> monoxide was approximately 2:1.  For synthetic natural gas it was 3:1 and
> for ammonia, there was almost no carbon monoxide, but there was some
> nitrogen,
>  in the ratio of 3 parts hydrogen to one part nitrogen.
>
> Prior to the use of natural gas, coal gas (producer gas) was used after
> suitable preparation and with the use of oxygen.   Again it only  became
> synthesis gas prior to the final synthesis step.    Gas  that was used to
> produce
> hydrogen was never called synthesis gas
>
> In my book, synthesis gas is a gas that has been made ready for the final
> synthesis step into a particular chemical, regardless of what is was before
> i.e.  the gas is used to directly synthesize another chemical product.
> Wood gas is not synthesis gas, but it could become synthesis gas after
> appropriate treatment.    If a gas is cleaned and prepared for  burning in
> a kiln
> or a boiler, it is fuel gas regardless of composition.
>
> My preference is to call it wood gas (Tom's term) since it is made  from
> wood or, if you want to be more generic it is biomass gas but not  bio-gas.
> As mentioned by others, the latter is usually used for gas that  has been
> produced by anaerobic digestion.   If you want to be  fancy call it
> xylogas.
>
> If the term syn-gas is used in any other way, it becomes too  generic and
> wood gas would loose its sense of identity.   By some of  the definitions
> used in past correspondence, coal gas, biogas, SNG or even  ethylene could
> be
> called syn-gas.   Let's try to keep our identity by  choosing a descriptive
> name rather than devolving into a generic  descriptor.
>
> There are some excellent descriptions of the various types of gases,
> including synthesis gas, producer gas, blue gas, carbureted water gas in
> the
> "Gas Engineer's Handbook", if anyone is interested
>
> More fuel for the fire.
>
> John
>
>
> Date: Wed, 29 Dec 2010 13:13:35 -0800
> From: Bear Kaufmann  <bear at allpowerlabs.org>
> To: gasification at listserv.repp.org
> Subject:  [Gasification] A small literature review re: syngas
> Message-ID:  <4D1BA47F.4020804 at allpowerlabs.org>
> Content-Type: text/plain;  charset=UTF-8; format=flowed
>
> 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. &  Aguill?n, 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/BMassGasFi
> nal.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?seque
> nce=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
> gasification at bioenerglists.org - 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
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/gasification_lists.bioenergylists.org/attachments/20101231/da479ad0/attachment.html>