Dear GF and all There would not be much absorbtion in the short (crosswise) path through the smoke, but possibly half going longitudinally.
Tom Reed Thomas B Reed 280 Hardwick Rd Barre, Ma 01005 508-353-7841 > On Jan 3, 2014, at 1:05 AM, [email protected] wrote: > > > Regarding the reflected heat from the refractory: If you were to travel on > the footplate of a steam locomotive at full regulator, you might observe a > temperature of 2,500 f in the fire box. in which there is generally a > refractory (brick) arch above the grate which extends the flame pattern and > generally helps the secondary air entering above the grate to insure compete > combustion. I have observed these arches to glow bight Yellow, the surface of > the brickwork actually melting with the heat. I am certain the radiation has > a lot to do with complete combustion. Would this form of radiation help > refine "smoke" (gas) breaking it down into short chain Molecules? > > GF > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > In a message dated 1/2/2014 3:35:33 A.M. Eastern Standard Time, > [email protected] writes: > Paul, > > > > I designed a diesel burner for preheating a bubbling fluidised combustor > about 12 years ago. Fortunately I took advice from an old and experienced > engineer who advised that we had to line the fire box with refractory. When > questioned why, his explanation was as follows: the diesel burns and gives > off radiant heat to the wall. The wall heats up and radiates heat back toward > the flame. The incoming radiation from the refractory is what evaporates and > heats the diesel so that it is able to burn nearly completely (as opposed to > the smoky start when the refractory is cold). I suspect that Rolf’s > refractory does much the same thing in that it sends radiation back into the > log. This heating effect is frequently underestimated as to its assistance > with the whole combustion process. We also use this effect in the first > portion of wall above the bubbling fluid bed level to provide radiation into > the secondary air combustion area. Above this we build a membrane wet wall > boiler. As with Rolf, our secondary air is aimed downward as we run the > bubbling bed under a slight vacuum. > > > > I am looking forward to seeing Rolf’s photos. > > > > Rex > > > > From: Paul Anderson [mailto:[email protected]] > Sent: 27 December 2013 04:49 PM > To: Discussion of biomass pyrolysis and gasification; [email protected] > Subject: [Gasification] Fwd: RE: Whole log pyrolysis for char production was > Re: Wood heating in the UK - whole log gasification > > > > Dear all, > > This excellent reply below came from Rolf. Thank you!! > > Pictures only after 6 January, but by then I am in Africa and might not > remember to request that Rolf send them. Together, we should be able to get > this worked out. > > We definitely should have some other people replicating this and suggesting > solutions for char removal, etc. And there should be some examination of > the pyrolyzed log concerning the char in the center verses the char at the > edges, and % yield (by weight). > > Paul > > > > > Doc / Dr TLUD / Prof. Paul S. Anderson, PhD > Email: [email protected] > Skype: paultlud Phone: +1-309-452-7072 > Website: www.drtlud.com > > > -------- Original Message -------- > > Subject: > > RE: Whole log pyrolysis for char production was Re: [Gasification] Wood > heating in the UK - whole log gasification > > Date: > > Fri, 27 Dec 2013 08:50:06 +0100 > > From: > > energiesnaturals <[email protected]> > > Reply-To: > > energiesnaturals <[email protected]> > > To: > > [email protected] > > > > Hallo Paul, > > > > Thanks for your interest in our living room stove/boiler! > > Because that's what it is. > > I build this one and quite a few more many years ago in the pre pellet area. > > It is not really a big thing but just what i said in my 1. Description for > Ken. > > An airtight firebox with controlled primary and secondary air, both preheated > by the non insulated air and water xchanger above the burning chamber. > > The primary 60% is used to regulate the gasification ( remember it is an all > night heater on one log) and the secondary actually burns the develloping gas. > > The escape hole is central in the dome. The admission pipes of 2.air are > offset and aimed at a 30 deg.downwards to create a turbulance and thus allow > for a quite complete combustion before the gas leaves the hot area. We use > mainly white pine, p.halepensis, airdried or so-so and we clean the conducts > every 2. year or so, it burns so clean. > > After 1-3 h, depending on the log, you can find the remaining carbon in more > or less the shape of the log. > > We do not use the char at present, cause it would be a mess to take it out > inside the living room...,but if we put in the last log around midnight and > close all the 1. And most of the 2nd air once it is lit, we are left with a > good bed of embers for toasting our breakfast bread. > > If our aim was to produce char , i should have incorporated a movable floor( > no grate) to discharge it into a cooling device below or yes a grate and > create a repeating cycle without the need to light the batch every time. > > > > (Un-)luckily i cannot provide any pictures right now, because we spend a > wonderful holydays at our doughter's in Budapest. > > But if you want some, tell me after the 6th next year. > > B.r. > > Rolf > > > Paul Anderson <[email protected]> escribió: > > Dear Rolf, (and hello to Greg!!) > > I am very interested in your method of whole log gasification. In > particular, I am interested in your statement that the pyrolysis occurs first > (or mostly first is fine), leaving the char to either be consumed (char > gasified) or removed. My interest is in removing / saving the char for a > variety of other purposes, including possible use as biochar. (I am > interested in using the heat, but that can be treated as a separate topic.) > > Therefore, I am sending this message to the Biochar Listserv. But because > relatively few people subscribe to both lists, I (and Ron Larson and Tom > Miles) will relay your reply to the Biochar List. Eventually these messages > could be taken off of the Gasification List and just continued with the > Biochar list, but let's see what develops. > > Could you please provide some: > some photos, > construction plans if available, > and some data on what percentage of char is yielded from the dry weight of > the feedstock logs. > > I am content with using cordwood that is smaller than the 45 cm diameter that > you mention, so any comments about the good or bad of using 10 cm or 25 cm > diameter feedstock would be appreciated. > > Although as you say it is "a tad late", I will count your message and replies > among my most treasured presents received this year for Christmas!! > > Paul > > > Doc / Dr TLUD / Prof. Paul S. Anderson, PhD > Email: [email protected] > Skype: paultlud Phone: +1-309-452-7072 > Website: www.drtlud.com > On 12/26/2013 5:16 PM, energiesnaturals wrote: > > Merry Christmas Ken and list ( I am aware that I am a tad late) > > > > One way to burn whole logs like we do (45cm across x 55 cm long) in an > efficient way is to build a well closed ,dome shaped burning chamber out of > 15 cm fire brick and have individually regulated, preheated primary and > 2,dary air , at least 2 pipes either side. > > You build up afire with kindling as you describe it and after 15 min you can > add an entire log of pitchy pine and it will first gasify very nicely and > than burn the charcoal if you want. > > The secret is to keep the walls of the combustion chamber warm and do not > use them as heat xchangers! > > You build a convenient xchanger above it and use the hot exhaust gas. Build > it large enough to reduce the exhaust temp to 90 deg C or less and you will > be way above 50 % eff. Ours has been working for 20+ years and is still doing > fine with 2 mm black steel pipes. > > > > > > We never cut anything below 55 cm long and never split anything below 45 cm, > believe me or come and see! > > > > Cheers and a happy new year > > > > Rolf > > > > > > > > Enviado desde Samsung tablet > > > Ken Boak <[email protected]> escribió: > > Greg > > > > Thanks for sharing. > > > > I want to try a few ideas for myself to see if this is indeed possible on the > small split logs I can produce locally. > > > > Our heating needs, and indeed modest on account of the mild climate here, but > I would like to find an efficient solution for all the thousands of acres of > neglected coppiced hardwood. Cast iron victorian stoves may be quaint, but I > am sure there are ways to improve the overall efficiency with radical > redesign. > > > > The main burner/heat exchanger on our 24kW gas boiler is no bigger than a > gallon paint tin. Perhaps there is design lesson to be learned here > > > > Anything to reduce mechanical handling and processing of wood fuels has to be > a step in the right direction > > > > > > Happy New Year > > > > > > > > Ken > > > > > > On 26 December 2013 19:22, Greg Manning <[email protected]> wrote: > > Greetings Ken, and list members. > > > > Ken, I'm going to point you to a video of the "underside" of a whole log (or > split) "cordwood as we call it here" stove that is a downdraft gasifier. > > > > I can speak at length privately, however only somewhat on list, as this is a > proprietary design. > > > > Here's the link to the video: > > http://youtu.be/DNYCfgEdYpg > > > > Greg Manning > > > > On Thu, Dec 26, 2013 at 12:59 PM, Ken Boak <[email protected]> wrote: > > > > Happy Christmas to the gasification list. > > > > At this time of year, during the festive holiday season, I get a bit more > time to manage the running of our woodstove, as it rapidly warms the room and > produces a cheery effect. > > > > Our property is fairly conventionally heated by natural gas, but a few years > back, I took the decision to invest in a woodstove with back-boiler, to > provide an alternative or back-up to the gas fired system. > > > > The woodstove has a flat steel tank at the rear, the "back boilerr", in place > of a couple of the firebricks lining. This circulates heated water entirely > by the thermosyphon principle to a radiator located in the bedroom/workroom > directly above the stove. So in effect the stove heats the living > room/kitchen area directly, and the room upstairs by circulating hot water. > > > > No electricity is required for circulation, and if worse-case we had an > extended power outage, this stove would provide heat and comfort in the two > main occupied areas of the house. Stoking it and attending it is often more > interesting than what is being shown on TV! > > > > With a few days off work, I have had time to monitor the stove and make some > assessments of its overall performance. Its a fairly traditional stove, a > rectangular box,, made from bolted together cast iron panels and partly lined > with firebrick. It's described as a multifuel stove - having been supplied > with a cast iron removable grate for burning coal - which is not used when > burning wood. It's approximately 24" wide, 12" deep and 18" tall. > > > > In the UK, a common size for firewood logs, intended for the domestic > woodstove is about 10" (254mm) long, and equal to a 1/4 round taken from a > limb that may have been 5 or 6" in diameter. The reason for this is that > there is a lot of coppiced hardwood, which has become mis-managed in the last > 20 years, so there are a lot of trees with 6" diameter shoots. The > popularity of the "firewood processor" machine, means that a lot of this wood > is now coming on the market as domestic firewood, and sold to suburbanites at > vastly inflated prices (about $0.50 per kilo). > > > > I am burning a mixture of kiln dried Silver Birch, and air dried other > species which includes ash, oak and sweet chestnut. The silver birch splits > well and makes excellent kindling. One log is split into 8 or 10 kindling > sticks and these are built into a pyramid around 2 or 3 sheets of scrunched > up newspaper. Lighting is quick and easy - as the birch is kiln dried, and > within 5 minutes you will have a roaring fire and the larger logs can be > added. > > > > The logs have an average weight of approximately 1 kg. I have found that a > normal burn rate of these is two per hour. I burn two at a time, and each > hour, add a further two to the burning char bed from the previous logs. With > firewood having a calorific value of approximately 4kWh/kg - I estimate the > fuel input is in the order of 8 to 10kW. > > > > Of course, with a traditional stove, so much of the heat energy is lost up > the chimney, and goes to create the draft. The efficiency of the stove, > might be in the region of 50% - somewhat better than the open wood fire. It > occurred to me that by way of a 2 stage gasification process, it would be > possible to increase the overall system efficiency, resulting in less wood > consumption, or more heat output per log. > > > > This leads to a question - is it possible to design a gasifier aimed at > handling whole log gasification - where a log is 10" long and no more than 6" > across? Can you recreate the temperatures, turbulence and reactants, found > within the combustion zone of the woodstove, and use this to thermally > process a single firewood log, at the rate of one every 30 minutes or so? > > > > I've had some ideas on how this can be done, effectively using a length of 6" > diameter stovepipe/fluepipe to make a compact gasifier. Logs would be loaded > in from the top, and the length of the pipe chosen to perhaps hold 4 logs at > any time - about 1m (40") tall. The bottom log would sit in the combustion > zone - so the end of this log is constantly under the action of the air > nozzles. The logs above are subjected to the elevated temperatures and begin > to pyrolise, char and split on their descent down the tube. > > > > Beneath the combustion zone would be a fairly conventional hearth, and > reduction zone, with the char supported by a grate below that. For an overall > idea of the system - think of HS Mukundas open top gasifier. > > > > Use of twin-wall stainless flue pipe would allow the air to be pre-heated in > the outer annulus - adding to the overall efficiency. The hot syn-gas could > be burned in whatever appropriate burner geometry deemed necessary for either > radiant space heating or water heating with a suitable heat exchanger coil. > > > > I hope to try to build a prototype of this over the next 10 days (a working > gasification holiday?) and to see whether a log can be reduced in this > manner. If all that is needed is heat, then the restrictions to produce a > tar free gas need not apply. If one can use whole logs, without having to > resort to woodchip - then this will be a considerable saving in mechanical > handling and wood processing. > > > > At the end of the day - this gasifying stove needs to be as simple to operate > as the existing woodstove. Reloading with a couple of logs each hour, and no > sophisticated need for fan- forced draft or electricity to operate. Draft > would come from the chimney as per now - about 25 to 30 feet, 6" diameter. > > > > If anyone has experience of something similar - please let me know. > > > > > > Happy Holidays > > > > > > > > Ken > > > > > > > > > > > > > > > This email is free from viruses and malware because avast! Antivirus > protection is active. > > > > > _______________________________________________ > 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/ > _______________________________________________ > 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/
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