Isn't it more efficient to pyrolyse the waste first, recovering energy and reducing transport carbon?
A 2009/2/2 David Schnare <[email protected]>: > Stuart: > > I've been studying notill agriculture that relies, in major part, on > building soil carbon to hold nutrients in the soil (reducing application > requirements and keeping it out of streams). While a 14% sequestration > (limited to only about 20 years before maxing out on sequestration > potential) seems small compared to 100% if dumped into the ocean deeps, it > seems to me that when used in places more than 150 miles from the ocean, it > is carbon reduction efficient (based on fuels needed for transport). > > As such, shouldn't we be narrowing the crop waste discussion to coastal > agriculture only, and give credit for soil sequestration where that's as > good as is available? > > David Schnare > > On Mon, Feb 2, 2009 at 11:54 AM, Stuart Strand <[email protected]> > wrote: >> >> By straw we are referring to the stalks of agricultural plants, wheat >> stalks and corn stover. The water and nutrients were expended to grow the >> grain. Straw has a low nutrient content (C/N = ca 50/1). Presently straw >> is wasted by allowing it to decay on the soil surface (only 14% or less of >> the straw carbon is incorporated into the soil). >> >> >> >> A variety of processes are available to get energy out of crop residues, >> but they are limited by the poor specific energy of biomass. Our focus is >> how to efficiently remove Pg amounts of carbon from the atmosphere and >> permanently sequester it in the least environmentally harmful manner. >> >> >> >> = Stuart = >> >> >> >> Stuart E. Strand >> >> 167 Wilcox Hall, Box 352700, Univ. Washington, Seattle, WA 98195 >> >> voice 206-543-5350, fax 206-685-3836 >> >> skype: stuartestrand >> >> http://faculty.washington.edu/sstrand/ >> >> >> >> Using only muscle power, who is the fastest person in the world? >> >> Flying start, 200 m 82.3 mph! >> http://en.wikipedia.org/wiki/Sam_Whittingham >> >> Hour http://en.wikipedia.org/wiki/Hour_record >> >> 55 miles, upside down, backwards, and head first! >> >> >> >> From: [email protected] >> [mailto:[email protected]] On Behalf Of >> [email protected] >> Sent: Wednesday, January 28, 2009 7:16 PM >> To: [email protected] >> Subject: [geo] Re: Crop residue ocean permanent sequestration >> >> >> >> Stuart, >> >> >> >> Why bundle and stash terrestrial straw. Growing straw requires >> substantial fresh water and nutrients. You could bundle and stash algae >> instead. How about sargassum or kelp? A macro-algae can be bundled in >> large mesh "tea bags" with much of the water being squeezed out during the >> bundling process. >> >> >> >> Then, as long as you've got bundles of biomass, why not separate the >> nutrients from the carbon before you stash the carbon? That way, you can >> recycle the nutrients back to the ocean surface for growing more biomass. >> High-pressure anaerobic digestion will release the carbon in two separate >> streams; one gaseous CH4, one dissolved CO2, which easily converts to liquid >> CO2 at typical ocean temperatures and pressures. >> >> >> >> Would you or others be interested in a California Energy Commission grant >> to run a few bench experiments on high-pressure anaerobic digestion? I can >> send a draft abstract. >> >> >> >> >> >> Mark E. Capron, PE >> >> Oxnard, California >> >> www.PODenergy.org >> >> >> >> >> > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
