Hi Phil, Thanks for weighing in!
Regardless of the M.C. of the animal offal itself, if a processing facility is to avoid being the source of a recall (assuming that facilities in S. Africa are regulated somewhat similarly to those in other countries that attempt to guard against food-borne illnesses), there is no substitute for copious amounts of wash-down water, often laced with chlorine or quaternary ammonium salts. I confess that I have never worked with abattoirs, but I have paid my dues in seafood and poultry processing facilities where solids are recoveredto one degree or anotherwith screens, dissolved-air flotation systems and decanter centrifuges, but never with enough efficiency to provide desiccation sufficient for most norms of value extraction. In other words, its just terribly difficult to exceed the point of diminishing return. I have no argument with your estimates of the relative water content of lean versus fat cattle carcasses. Fat displaces water (and protein, to some extent) in a proximate analysis. However, without grain finishing, this fat is hard to come by and besides, Western tastes are gravitating toward grass-fed animals which do have about 65% (or more, even) dry matter, but this is related to the carcass weight, not the round weight of the animal. In a paper presented at 33 Congreso Argentino de Producción Animal Comarca Viedma, Patagonia 13 al 15 octubre 2010 Conferencia Plenaria ( <http://amor.cms.hu-berlin.de/~h1981d0z/pdf/2010-10-viedma/water-footprt.pdf > http://amor.cms.hu-berlin.de/~h1981d0z/pdf/2010-10-viedma/water-footprt.pdf) the industry number for water use at time of slaughter is shown as 0.5 m3 per carcass or an amount of water that can represent nearly twice the finished carcass weight(!) This waternot just the water denoted by the finished carcass and associated offalis an inexorable part of the wastewater budget. Even if a fraction of it is mechanically separated from the more solid-appearing fractions, it cant be ignored. Dehydrating the stomach contents and other solid-appearing fractions doesnt alter the arithmetic and only makes the real slaughterhouse waste stream more difficult to process with more appropriate technologies such as anaerobic digestion. Best regards, Mark From: Phil Marsh [mailto:[email protected]] Sent: Monday, October 26, 2015 8:14 AM To: 'Discussion of biomass pyrolysis and gasification' <[email protected]>; [email protected] Subject: RE: [Gasification] Abattoir's pyrolysis plant bucks methane power-making trend Hi Mark and Tom: Just to weigh in on this one ..it may be slightly different than it seems when it comes to MC. Besides doing foolish things in relation to pyrolysis/gasification I also own a small abattoir. The actual water content of animals is roughly 65%, about the same as one of our cottonwood trees, but is susceptible to wide variation. Lean animals with a lot of muscle could be above 70% and very fat animals (obese) below 50%. Offal that would go to a digester or a pyrolysis system would be mainly stomach contents, this usually contains considerable fat and less muscle tissue which lowers MC but a lot of water is used in the wash down processes in abattoirs so things are wet. A moister content between 60 and 70 percent can be expected in the offal. I have done small amounts of offal in my pyrolysis system as a test, in this case it was mixed with about 50% by volume sawdust, briquetted and dried before entering the system. Using this process it appeared to make good char and worked fine. In green SPF we expect between 45-55% MC depending on season, cottonwood 55-70%, of course if you attempt to air dry your wood your neighbours may not complain, it you attempt the same thing with a pile of offal you may get some pushback ..just saying:) Phil From: Gasification [mailto:[email protected]] On Behalf Of Tom Miles Sent: October 25, 2015 8:05 PM To: [email protected] <mailto:[email protected]> ; 'Discussion of biomass pyrolysis and gasification' <[email protected] <mailto:[email protected]> > Subject: Re: [Gasification] Abattoir's pyrolysis plant bucks methane power-making trend Mark, Shame on you for doing the math. It was probably pitched as a least cost disposal option with the added benefit of power generation. Nutrient management, heat and material balances, or life cycle costs may not have been considered. Well have to get Joel Arcus of BioWaste Technologies into the conversation. With the instability of power generation in South Africa you would think that gasifiers could compete. Just to throw a spanner into the works have a look at a recent Spanner gasifier installation in the UK. http://www.holz-kraft.de/images/Blog/FW_article_Nick_Helme.pdf £500,000 (USD $767,000) for 90 kWe and 216 KWth. $8,500/kWe. With the right fuel these gasifiers have a very high availability of 7,000-8,000 hours per year. In Germany they have sold 400+ as heating devices for farms. Since the German utilities pay something like $0.28/kWh it helps pay off the investment. We cant justify the in North America. In the UK, as the article points out, the customer is the government. You need the Renewable Heat Incentive (RHI) and the Renewable Obligation Certificates (ROC) to justify the investment. So when it comes to gasifiers the UK ROCS! At least this year. It would be nice to see gasifiers pay their own way with real revenues but fossil fuels keep a lid on that opportunity. Tom From: Gasification [mailto:[email protected]] On Behalf Of Mark Elliott Ludlow Sent: Sunday, October 25, 2015 6:39 PM To: 'Discussion of biomass pyrolysis and gasification' <[email protected] <mailto:[email protected]> > Subject: Re: [Gasification] Abattoir's pyrolysis plant bucks methane power-making trend This is surely over-hyped, Tom. Eleven-tonnes of waste (which is likely 85%, or more, water) implies that over 9,000 kgm of water will need to be evaporated each day just to end up with a couple of metric tons of pyrolyzable waste. This is beyond ludicrous! Why not simply enzymatically digest the offal, pasteurize it, and overland apply it as a soil amendment? HAS to be some govmint money pushing ridiculous projects like this one! Mark From: Gasification [mailto:[email protected]] On Behalf Of Tom Miles Sent: Sunday, October 25, 2015 5:01 PM To: 'Discussion of biomass pyrolysis and gasification' <[email protected] <mailto:[email protected]> > Subject: [Gasification] Abattoir's pyrolysis plant bucks methane power-making trend An alternative to anaerobic digestion for abbattoir waste in South Africa Abattoirs pyrolysis plant bucks methane power-making trend Read the article now. http://www.bdlive.co.za/business/innovation/2015/10/13/abattoirs-pyrolysis-p lant-bucks-methane-power-making-trend BioWaste Technologies, Gauteng, South Africa, Joel Arcus http://www.biowastetech.co.za/ BDlive is a premium digital news publication focusing on the South African economy, business and politics, updated all day long by a newsroom of expert journalists. Read more (link to http://www.bdlive.co.za) Subscribe now (link to http://www.bdlive.co.za/subscribe)
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