Thanks, Phillip! Reverting to first principles, in this case statistical thermodynamics, there are two observations that actually bring this conversation back to Gasification: First, increased temperature means higher molecular velocities and in the gaseous phase this increases the probability of each reactive radical finding its mate, analogous to stirring (shaking) improving the quality of a good Martini.
Temperature increases the velocity of each reactive species. More volume is explored in each unit of time. Reaction efficiency increases. Pressure is linked to temperature vis-a-vis temperature; the higher the temperature, the higher the molecular velocity and thus the more energy that is felt by the walls of a containing vessel (read: pressure). Higher pressure translates to less unoccupied space in any differential span of time. Whatever transformations occur in a gasifier require that reactive species actually come into close enough and frequent enough contact with complementary species to allow reactions. High velocities can overcome peculiar stereochemistries that resist the formation of the desired covalent bonds, or preferentially, facilitate the formation undesired bonds. Whatever occurs, we can be certain that the reaction will not gain net energy; in fact, some tiny fraction will evaporate into the universe. Most of our questions can be answered by thought experiments. Mark -----Original Message----- From: phillip manske [mailto:[email protected]] Sent: Friday, October 07, 2011 5:45 PM To: [email protected]; Discussion of biomass pyrolysis and gasification Subject: Re: [Gasification] [Digestion] Karve connecting Biochar and Biogas Hi - thanks for the thread. The syngas route to methane requires higher pressure to complete. You must sparge CO into the reactor water. The pressure is immaterial to bacteria other than the presence of higher concentrations of food bought to you by Boyle's law. Phillip On Fri, Oct 7, 2011 at 7:24 PM, Mark Ludlow <[email protected]> wrote: > # In a fermentation reaction, "Sugar ----> Alcohol + CO2", all other > things being equal, this would be favoured by low pressure, and/or by > removal of CO2, a "product of the reaction." If the reaction producing Methane was: > > 6 CO + 2 H2O ---> 2 CH4+ 4 CO2, > > it would be favoured by high pressure, in that it starts with 8 > volumes of reactants, and it yields 6 volumes of reactants. Again, > this reaction would be improved by removing the products. > > > > Actually, the stoichiometry is correct across the reaction you use as > an example, Kevin, but it's a molar comparison you are making not a > volumetric one. It very difficult to compare compressible gasses and > liquids volumetrically unless the gasses are at their critical > pressure where the physical properties of the substance in both the > liquid and gaseous states converge. > > > > Pressure affects the reaction kinetics of gas-phase reactions because > to probability of collisions between reacting species is improved. The > internal energy of virtually incompressible liquids under high > pressure is not much affected, at least when compared to the effect of raising the temperature. > > > > Best, Mark > > > > From: [email protected] > [mailto:[email protected]] On Behalf Of > Kevin > Sent: Friday, October 07, 2011 3:40 PM > > To: Discussion of biomass pyrolysis and gasification > Subject: Re: [Gasification] [Digestion] Karve connecting Biochar and > Biogas > > > > Dear GF > > ----- Original Message ----- > > From: GF > > To: [email protected] ; [email protected] > > Sent: Friday, October 07, 2011 3:46 PM > > Subject: Re: [Gasification] [Digestion] Karve connecting Biochar and > Biogas > > > > Hi Mark. > > I think my message was incoherent. When I mention the build up of > pressure in a vessel containing multiplying organisms, I did not > mention the presence of "heat" which is the basis of Luis Pasteurs > method of sterilization or the speed at which the pressure builds, > which might entail an adverse heat reaction, Yeast seems to build up > pressure of several atmospheres if contained in a sealed container, > does this enhance the reaction or slow it down, and what are the "limits"? > > > > # In a fermentation reaction, "Sugar ----> Alcohol + CO2", all other > things being equal, this would be favoured by low pressure, and/or by > removal of CO2, a "product of the reaction." If the reaction producing Methane was: > > 6 CO + 2 H2O ---> 2 CH4+ 4 CO2, > > it would be favoured by high pressure, in that it starts with 8 > volumes of reactants, and it yields 6 volumes of reactants. Again, > this reaction would be improved by removing the products. > > > > Studies at the bottom of the Pacific Trench show bacteria alive and > well together with larger forms of life. My question goes UN answered. > > Will gas producing bacteria perform faster in a pressure retaining > environment? > > > > # All other things being equal, reaction speed is favoured by higher > temperature, higher concentration of reactants, and low concentration > of products of the reaction. Higher pressure tends to move a reaction > in the direction of lower volume. On teh other hand, exothermic > reactions are favoured by cooling, and endothermic reactions are favoured by heating. > > > > # Now, having said all that, the fact that a bacteria or yeast is a > living species, it may be that "reaction conditions" may have to be > varied to optomise teh "living conditions" for the bacteria/yeast, and > thermodynamic conditions may have to be given second place. > > > > Thus producing high pressure gas PDQ. > > Im talking about high pressure here, 14000 psi. if you put your > bacteria and nutrient in a respectable container without any air space > the pressure would rise quite fast. > > Of course a sudden decompression or re-compression may kill it, as you > suggest but that is not My question. > > > > # Obviously, if the desired reactions seem to work well for such > bacteria at > 14,000 psi, then that would be the conditions to apply to them to > drive that reaction. In th case of beer yeasts, they seem to work well > at atmospheric pressure ranges... say from .5 to 2X atmospheric. Much > higher pressures may stall them out. > > > > Best wishes, > > > > Kevin > > > > GF > > -----Original Message----- > From: Mark E. Ludlow <[email protected]> > To: 'Discussion of biomass pyrolysis and gasification' > <[email protected]> > Sent: Fri, Oct 7, 2011 3:20 am > Subject: Re: [Gasification] [Digestion] Karve connecting Biochar and > Biogas > > Geoff: > > High pressure is an accepted way to pasteurize juices and eliminate > vibrio in and extend the shelf life of oysters. Water is virtually incompressible. > Bacteria stay in equilibrium with their environment but react to > sudden changes in pressure. > > Mark > > > > > > From: [email protected] > [mailto:[email protected]] On Behalf Of GF > Sent: Thursday, October 06, 2011 5:51 PM > To: [email protected] > Subject: Re: [Gasification] [Digestion] Karve connecting Biochar and > Biogas > > > > I seem to remeber the filter beds laid down with "coke"derived from > the GAS WORKS to enhance the bacterial action on sewage.It is > interesting to postulate the possibilities of testing other ziolite > qualities in other materials than char. The reaction of bacteria over > a nutriant soaked porous media especially when it is soaked with > recirculated liquids from behind the scum board which retains the > larger solids. This raises a question I have long pondered. Is > microbial action accelerated by pressure. If this reaction is contained within a pressure vessel? For instance : > > what sort of result could we expect if this bacterial action took > place at say 9000lb per sq inch, give or take a few atmospheres. I > have heard that beer bottles explode if unchecked during fermentation, > is the generation of gasses increased with pressure forcing the > nutrient down the throat of the > microbes as it were? > > GF > > > > -----Original Message----- > From: back40 <[email protected]> > To: paul.harris <[email protected]>; Discussion of biomass > pyrolysis and gasification <[email protected]> > Sent: Thu, Oct 6, 2011 4:01 pm > Subject: Re: [Gasification] [Digestion] Karve connecting Biochar and > Biogas > > I wonder if this is relevant: > > http://newscenter.lbl.gov/feature-stories/2011/10/05/soil-carbon/ > > > > "Michael Schmidt, a co-author of the Nature paper from the University > > of Zurich, has already found that biochar, which is charred material > > from wildfires or a kiln, is not stable as previously believed. It > > also readily decomposes. Some scientists had believed that biochar > > could be used to sequester carbon, but this may not be the case." > > > > On 10/6/11, Paul Harris <[email protected]> wrote: > >> Gday All, > >> > >> > >> > >> For the non digesters in particular some anaerobic digesters are >> packed > >> with plastic rings/balls or other media to provide a surface for >> bacteria, > >> so what Dr Karve has possibly done (I am guessing here) is provided >> homes > >> for a lot more bacteria so they are not washed out. This is good for > >> solutions but not so good if there are solids in the waste stream. > >> > >> > >> > >> The other possibility is that the extra carbon has restored the C:N ratio. > >> > >> > >> > >> Could you give more details of what you did Dr Karve, if it is >> possible (I > >> understand you may have some commercial interests to protect)? > >> > >> > >> > >> Happy digesting, > >> > >> HOOROO > >> > >> > >> > >> Mr. Paul Harris, Room 202 Charles Hawker Building, Faculty of >> Sciences, The > >> University of Adelaide, > >> > >> Waite Campus, PMB 1, Glen Osmond SA 5064 Ph : +61 8 8303 7880 Fax : > >> +61 8 8303 4386 > >> > >> Roseworthy Campus, Ph : +61 8 8303 7929 > >> > >> mailto:[email protected] > >> http://www.adelaide.edu.au/directory/paul.harris > >> > >> > >> > >> CRICOS Provider Number 00123M > >> > >> This email message is intended only for the addressee(s) and contains > >> information that may be confidential and/or copyright. If you are >> not the > >> intended recipient please notify the sender by reply email and >> immediately > >> delete this email. Use, disclosure or reproduction of this email by >> anyone > >> other than the intended recipient(s) is strictly prohibited. No > >> representation is made that this email or any attachments are free of > >> viruses. Virus scanning is recommended and is the responsibility of >> the > >> recipient. > >> > >> > >> > >> From: [email protected] > >> [mailto:[email protected]] On Behalf Of > >> [email protected] > >> Sent: Thursday, 6 October 2011 1:35 PM > >> To: Anand Karve; [email protected]; Discussion of > >> biomass; biochar; digestion > >> Subject: [Digestion] Karve connecting Biochar and Biogas > >> > >> > >> > >> AD (cc four lists): > >> > >> I have not previously seen the connection between Biochar and >>Biogas > >> that you described (below) today on the gasification list. In > >> particular, you say you ".. filled the digester > >> with charcoal, my system accepted three times the normal daily input > >> and produced three times as much gas." > >> I think what you describe can be a very powerful push for both >> Biochar and > >> Biogas. Can you describe what you have learned a little more? > >> > >> I know too little of digesters, so this is not clear. I think I >>know > >> your kitchen-sized inverted "barrel" gas chamber and think I >> understand the > >> last part - of getting three times as much gas in the next 24 hours >> or less > >> (and 3X is a huge change!). Does the idea of accepting three times >> more > >> mean essentially the same thing? I would think you could "jam" any >> amount > >> in; what limits acceptance? > >> > >> Do you agree that this is very important new information? Do you >>agree > >> this information could help speed up both technologies? I believe >> there is > >> wide agreement that Biochar benefits from added biological material >> (that > >> would not be long-lived from a sequestration perspective). Is there >> any > >> reason to think that the traditional use of digester effluent for ag > >> improvements will be in any way harmed if it is continued through the > >> addition of carbon-negative Biochar? Should this not promote sales >> of your > >> charcoal-making stoves? > >> > >> If I haven't asked quite the right question - please answer the >>right > >> one. And congratulations on learning and reporting this. > >> > >> Ron > >> > >> > > > > > > -- > > Regards, > > Gary Jones > > > > _______________________________________________ > > Gasification mailing list > > > > to Send a Message to the list, use the email address > > [email protected] > > > > to UNSUBSCRIBE or Change your List Settings use the web page > > http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bi > oenergylists.org > > > > for more Gasifiers, News and Information see our web site: > > http://gasifiers.bioenergylists.org/ > > _______________________________________________ > > Gasification mailing list > > > > to Send a Message to the list, use the email address > > [email protected] > > > > to UNSUBSCRIBE or Change your List Settings use the web page > > http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bi > oenergylists.org > > > > for more Gasifiers, News and Information see our web site: > > http://gasifiers.bioenergylists.org/ > > ________________________________ > > _______________________________________________ > Gasification mailing list > > to Send a Message to the list, use the email address > [email protected] > > to UNSUBSCRIBE or Change your List Settings use the web page > http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bi > oenergylists.org > > for more Gasifiers, News and Information see our web site: > http://gasifiers.bioenergylists.org/ > > ________________________________ > > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1410 / Virus Database: 1520/3943 - Release Date: > 10/07/11 > > _______________________________________________ > Gasification mailing list > > to Send a Message to the list, use the email address > [email protected] > > to UNSUBSCRIBE or Change your List Settings use the web page > http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bi > oenergylists.org > > for more Gasifiers, News and Information see our web site: > http://gasifiers.bioenergylists.org/ > > _______________________________________________ Gasification mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/
