wonderful answer Darren! a true PE :
-----Original Message----- From: Schmidt, Darren <[email protected]> To: Discussion of biomass pyrolysis and gasification <[email protected]> Sent: Mon, Aug 23, 2010 9:35 pm Subject: Re: [Gasification] Compressibility Factor The compressibility (Z-factor) of a producer gas with the following omposition: 2 - 17% O2 - 12% 2 - 52% H4 - 2% O - 17% 120F & 145 psi - Z factor = 1 20F & 1450 psi - Z factor = 0.96 00F & 7000 psi - Z factor = 1.16 CO2 ranges significantly in compressibility, however it is offset by the ther gases. The tendency is to more closely mirror Nitrogen in-terms f compressibility at various conditions. However it appears the original question was not really asking about -factors, but rather how compressible is syngas. Generally, to etermine a change in volume or density the syngas can be treated as an deal gas - PV=nRT n=# of moles or mass/molecular weight (MW). The MW or the above mix is 25.3. R=universal gas constant. The change in density, or volume can then be calculated for the desired ressure. The power to compress the syngas can be determined by the following alculation: For isentropic compression first determine state 2 temperature T2 = 1(P2/P1)^((k-1)/k); k=1.4 T in absolute units (R or K). P = psia; then etermine power Q=m cp DT; DT=T2-T1, cp = approx 0.24, m = (lbs/hr), Q = tu/hr; divide Q by 3412 to get kW. This does not take into account ntercooling during compression. Example: to compress 300 scfm of gas to 100 psi requires approx. 112 hp. Darren D. Schmidt, P.E., Senior Research Advisor nergy & Environmental Research Center niversity of North Dakota 5 North 23rd Street, Stop 9018 rand Forks, ND 58202-9018 hone: (701) 777-5120 ax: (701) 777-5181 [email protected] ww.undeerc.org -----Original Message----- rom: [email protected] mailto:[email protected]] On Behalf Of Tom Miles ent: Monday, August 23, 2010 10:58 AM o: 'Discussion of biomass pyrolysis and gasification' ubject: 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 actor) for a typical producer gas from a down draft biomass system? A few years ago Biomass Engineering Ltd did a test of compressing gas or iring in a micro turbine. If I recall they did look at the ompressibility actors but I can't find the study. Cooled producer gas can clearly be compressed. The MW is similar to air nd t seems to behave like air when compressed. So far I have seen an emotional response to a question that you didn't sk, is compressing producer gas feasible?" That should be answered in terms f W energy in/kW gas out ( or kJ/KJ). It is useful to know the net cost. or ome reason we don't question the exergy of fossil fuels yet we hold iomass o a higher standard. om ossible sources: http://gasifiers.bioenergylists.org/ecnmicrogas icro Gas Turbine Operation with Biomass Producer Gas http://gasifiers.bioenergylists.org/gasdoc/cratech/Final%20Report%20and% 0Ga %20Analysis%20for%20a%20Biomass%20Gasifier.pdf inal Report and Gas Analysis for a Biomass Gasifier ______________________________________________ asification mailing list [email protected] ttp://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org ttp://gasifiers.bioenergylists.org ttp://info.bioenergylists.org _______________________________________________ asification mailing list [email protected] ttp://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org ttp://gasifiers.bioenergylists.org ttp://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
