Darren, hp is power and not energy (power /time)necessary to compress one volume to some pressure. Regards, Ben
--- El lun 23-ago-10, Schmidt, Darren <[email protected]> escribió: De: Schmidt, Darren <[email protected]> Asunto: Re: [Gasification] Compressibility Factor Para: "Discussion of biomass pyrolysis and gasification" <[email protected]> Fecha: lunes, 23 de agosto de 2010, 16:35 The compressibility (Z-factor) of a producer gas with the following composition: H2 - 17% CO2 - 12% N2 - 52% CH4 - 2% CO - 17% 120F & 145 psi - Z factor = 1 120F & 1450 psi - Z factor = 0.96 400F & 7000 psi - Z factor = 1.16 CO2 ranges significantly in compressibility, however it is offset by the other gases. The tendency is to more closely mirror Nitrogen in-terms of compressibility at various conditions. However it appears the original question was not really asking about Z-factors, but rather how compressible is syngas. Generally, to determine a change in volume or density the syngas can be treated as an ideal gas - PV=nRT n=# of moles or mass/molecular weight (MW). The MW for the above mix is 25.3. R=universal gas constant. The change in density, or volume can then be calculated for the desired pressure. The power to compress the syngas can be determined by the following calculation: For isentropic compression first determine state 2 temperature T2 = T1(P2/P1)^((k-1)/k); k=1.4 T in absolute units (R or K). P = psia; then determine power Q=m cp DT; DT=T2-T1, cp = approx 0.24, m = (lbs/hr), Q = Btu/hr; divide Q by 3412 to get kW. This does not take into account intercooling during compression. Example: to compress 300 scfm of gas to 100 psi requires approx. 112 hp. Darren D. Schmidt, P.E., Senior Research Advisor Energy & Environmental Research Center University of North Dakota 15 North 23rd Street, Stop 9018 Grand Forks, ND 58202-9018 Phone: (701) 777-5120 Fax: (701) 777-5181 [email protected] www.undeerc.org -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Tom Miles Sent: Monday, August 23, 2010 10:58 AM To: 'Discussion of biomass pyrolysis and gasification' Subject: Re: [Gasification] Compressibility Factor Mark, No one has answered your basic question yet: MA>Does anyone know or can they work out a compressibility factor ( Z factor) for a typical producer gas from a down draft biomass system? A few years ago Biomass Engineering Ltd did a test of compressing gas for firing in a micro turbine. If I recall they did look at the compressibility factors but I can't find the study. Cooled producer gas can clearly be compressed. The MW is similar to air and it seems to behave like air when compressed. So far I have seen an emotional response to a question that you didn't ask, "is compressing producer gas feasible?" That should be answered in terms of kW energy in/kW gas out ( or kJ/KJ). It is useful to know the net cost. For some reason we don't question the exergy of fossil fuels yet we hold biomass to a higher standard. Tom Possible sources: http://gasifiers.bioenergylists.org/ecnmicrogas Micro Gas Turbine Operation with Biomass Producer Gas http://gasifiers.bioenergylists.org/gasdoc/cratech/Final%20Report%20and% 20Ga s%20Analysis%20for%20a%20Biomass%20Gasifier.pdf Final Report and Gas Analysis for a Biomass Gasifier _______________________________________________ Gasification mailing list [email protected] http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org http://gasifiers.bioenergylists.org http://info.bioenergylists.org _______________________________________________ Gasification mailing list [email protected] http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org http://gasifiers.bioenergylists.org http://info.bioenergylists.org _______________________________________________ Gasification mailing list [email protected] http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org http://gasifiers.bioenergylists.org http://info.bioenergylists.org
