Showing posts with label kilns. Show all posts
Showing posts with label kilns. Show all posts

Friday, September 11, 2009

Biochar Chatter


It has been a while since I participated with these forums and the ongoing discussion has sorted a lot out. This is a bit of the information been discussed. Not too much has actually changed except we perhaps have more complete information.


What is noteworthy is that the amount of carbon waste is vast and must be handled in any event. Most such waste is actually fairly uniform.


The problem has been all attention is on trying to create an industrially scaled application protocol. This is delaying the actual use of the method.


There is merit in applying pyrolysis technologies inasmuch as it captures a significant fraction of the byproduct over that needed to sustain the reaction. However, all this generates a series of real costs that are poorly offset by the limited commercial value of the by product. The topper is that in order to achieve efficiency high temperatures are preferred creating their own problems.


I pointed out in the early going that the original method produced an excellent biochar produced at about 300 degrees while consuming the volatiles thorough an earthen kiln. This can be adopted by indigenous subsistence farmers today.


Replicating that on a farm could also be done with a simple two lung kiln in which the charge is roasted at 300 degrees for several hours and the volatiles used to fuel the second burner at 2000 degrees plus to cleanly burn those volatiles. Attempting to capture those same volatiles is non productive at this level and by completely consuming them and capturing all the heat, all the biochar is thoroughly roasted.


So we have two practical methods of application. One is the hand built earthen kiln similar to an earthen charcoal kiln and the other possibly fabricated from a retired shipping container with a special small high temperature burner (the expensive part) and some piping.


Stepping up from that immediately accepts a huge trucking cost as material is gathered and inventoried to feed the large kiln unless one is tied to a major source. Then you have to dispose of the fluids and ship out the char to customers. And no one has figured out how to sell biochar to anyone for cash.


The biochar market is a waste disposal market and needs to be at the point of application which everyone is forgetting. It is already been handled at the moment of disposal. That is when you deliver it to its final destination. That could even include trucking it far into the next state. It is best to truck it to a small farm kiln who wants the product for his soil.


IMHO


you need large scale pyrolysis ie corporate/local government players. Why?


because the technology has not been scaled down enough yet and a good sized pyrolysis plant will set you back $5-10mil ($5 before the yanks bought up all the technology $10 after the yanks have bought up all the technology.

secondly it is only pyrolysis that can harvest the energy (electricity generation or bio-oils). It worries me that so many enthusiasts are making char without harvesting the energy. A large pyrolis unit has the 'pollution" exhaust of one SUV.


Sources of waste/fuel.

Here i can speak only of my own area/county


Council green "waste" --Locally tonnes and tonnes of green waste and wood offcuts (pallets, off cuts,building waste, flooring etc etc) are collected by the local council(small- outer suburban) on a daily basis.

Storm waste-- A storm recently felled thousands of trees in my area. this ALL went to landfill. Much of my outer suburban area is being "developed" this usaually means taking most of the trees off the site.

Intensive farming waste We have thousands of tonnes of chicken litter produced daily. with the recent(?) drought farmers were not using this for fertiliser.- Again into land-fill. I haven't even looked at pigs or cattle.

Paper Mill waste- wile this is uneconomic as an energy producer, (as it is about 70% water) pyrolising it is preferable to methane producing land-fill --as happens now

Wood-chips-- we cut down thousands of acres of forest, chip them and freight them to Japan for them to make origami (or char?)

Sewerage waste.-- God knows what happens to this. Soon we will have to start harvesting all the water from it. Pyrolysis can do this with some tweaking. Heavy metals? Why? What industry is putting its waste in the sewer?

Plantations Char -After you have charred all the waste, then start growing trees for charcoal (something that has been done and is being done in UK--on a sustainable basis for thousands of years) or stop making wood-chips out of them. Charcoal is far more valuable to society. What ever happened to the "paperless office"?


I am sure if you talk to the people selling this technology that they would have identified many other char-sources (Ask Adriana Downie, from BEST Energies Australia).


If "pyrolysis machines" can sell char for around $200 a tonne, investment in infrstructure becomes economically viable. Give them a carbon credit (or the farmer-or gardiner?) and everone is popping champaign corks.


If char is added to soil--Apart from reducing methane there is the possibility of harvesting water from waste (soon to be essential here).


reducing farmers inputs of water (saving energy from pumping etc)


reducing farmers inputs of fertiliser (which we are running out of)


reducing farmers' pollution by agricultual chemical and fertiliser run-off -(What will shortly kill the largest living organism on Earth-The Great Barrier Reef -it may even be too late to save it).


IMHO replicating Terra preta soils is the only way out of the Looming Global Warming disaster. (If not "out" at least moving in the right direction) Other geo-engineering ideas are just too silly, expensive, fanciful, or unproven (as is C.C.S.). Terra preta seems to suffer from being too simple an idea to catch on. Yet it is, and if Govenments and Copenhagen don't give the lead people will start doing it themselves anyway-- with more emissions than pyrolosis.


In other words we have NO choice but to go with char. we should have started 5 years ago.


Michael Angel


Be the change you want to see in the world – Ghandi

2009/9/5 John Seed <
johnseed1@ozemail. com.au>

Friends, this email from my long-time friend and forest-defending colleague George Marshall nicely sums up my own concerns about where biochar may be headed.

Would anyone care to assuage these concerns?

Beautiful funeral ceremony for Geoff Moxham yesterday, hundreds of well-wishers, lots of biochar in the eulogies,

for the Earth

John

----- Original Message -----
From:
George Marshall
To:
John Seed
Sent: Saturday, September 05, 2009 8:14 PM
Subject: My concerns with biochar

Dear Seedy


Lets assume for now that all the wondrous things ascribed to Biochar about soils and carbon sequestration etc are true. In a way it doesn't matter because my concerns apply whether it is true or not- it will still go into large scale production if there is enough commercial pressure for it. After all plenty of biofuels are net carbon emitters but they still get used because industry has lobbied for it.


Anyway my concerns are all about the source of biochar. I had not really thought about biochar until talking with my friend Anna Jenkins, formerly of FSC who is advising the Carbon Gold project in Belize
http://www.carbon- gold.com She is cced

My first concern was that it is being set up by Dan Morell who is a carbon trading businessman. Although it is all very touchy feely local development stuff (and the project looks good to me) it is clear that Morell's objective (and, no doubt anyone commerically involved) is to get Biochar fully transferable in carbon trading. In truth I don;t see how it could be economically viable on any significant scale unless it had some substantial subsidy - and carbon credits seems most likely. Reading the biofuelwatch briefing
http://www.biofuelw atch.org. uk/docs/biocharb riefing.pdf it is clear that there are much bigger fish going after this.

When biofuels were kicking off there were lots of nice small community type projects esp waste oil recycling. In retrospect the question that should have been asked was this: when the big corporate players come on board and biofuel is an international commodity, what will be the lowest unit cost source that can provide significant supplies. I remember talking with George Monbiot some eight years ago and our answer took us straight to oil palm, This was assuming a competitive market- we shoud have imagined that existing pork barrel politics could easily extend to a ludicrous subsidy for other crops like corn (US) and sugar (EU)


So now we know this is the right question, let's ask it for biofuels: if this is tradeable it will presumably be a standardised commodity- a kilo of biochar is a kilo of biochar- so given the inevitable chase to the bottom on price, what will be the cheapest (or the most corrupt/subsidised) source ? To my mind here are these contenders:


Relatively benign (with major caveats)


agricultural waste- potentially a good source for all biofuels, but there must be some significant economic impediments of it would be more used.


other waste streams- the carbon part of domestic and commercial waste such as wooden building materials (pollution issues here)


forestry waste from plantation forestry - thinnings etc. I wonder if this produces enough for viability?forest floor waste- dreadful for ecology


Less benign


Plantations for biochar purposes- issues here of what land, where, who owns it, can it be used for food or something else, does it actually sequester net carbon, is land being cleared for it and all the usual plantation issues. Plenty of potential subsidies and tax breaks here.


Dreadful


Uncommercial species from logging in natural forests- aha- Rimbunan HIjau's wet dream- they can rip out the valuable timber species and pyrolise the rest and then, having cleared the whole thing out they can stick some other plantation on top. For forests that do not have many commercial species and otherwise would not be commercial to log, this could tip the balance. And, as we know, corruption is rife here.


I think the potentially deadly thing with biochar is that it is such a low grade commodity that it can use anything. So the nearest analogy is driftnetting the oceans to make fishmeal.So if you were some unscrupulous commodity trader, what would you put your money on? Or can you suggest something else?


I think these concerns should be front of mind for all biochar enthusiasts and promoters because it is clear to my mind that unless you demand and obtain some rigourous standards for what constitutes environmentally and socially acceptable sources that are in place at the very outset it will immediately go to environmental mining by default.


YoursGeorge

+

Thursday, September 4, 2008

Garden Biochar Made Easy

We are entering that time of year in which a lot of garden plants waste needs to be disposed of. It may also be a great time to produce a little biochar to fold into the soil.

We have learned that there is a strong likelihood that biochar will turn out to be superior to simply compost as a soil additive although our expectation is quite the opposite. The difference is simply that elemental carbon will hold soluble nutrients in place that are far too mobile when released from decomposing compost. Thus turning a charge of compostable plant waste into biochar should ultimately be a far superior practice.

There has been some observation that the initial soil reaction to receiving biochar is not as vigorous as initially expected but after one season this is overcome. This merely suggests that it may take a growing season to fully integrate the carbon with the soil biota.

The trick is a start a practice that can be easily repeated every year without a lot of fuss.

There we have learned that an open bottom drum will work fine. First a layer of branches less than an inch in diameter is laid down such that the edges are greater that the diameter of the drum. This permits air flow under the edge of the drum. Throw plant waste into the drum. This can be even accumulated over the summer as grass clippings and the like.
A metal lid is on top of the drum to prevent rain getting into the mass and accelerating composting. It should be possible to produce a well packed but not tightly packed charge that will still permit airflow.

When the time comes to fire the charge, I would first throw a layer of soil on top of the charge while leaving a ten inch hole in the center. The soil likely does not need to be there even but I would still put in three inches. I would then put in a charge of barbeque briquettes, preferably already burning into the center hole. This can be done with any other fuel of course but this way we are sure that the coals themselves will last for some time and avoid a premature failure. It may even be integrated with the weekly barbeque.

What is important is that the fire is strong enough and hot enough to sustain a top down burn. The beauty of this is that the volatiles coming off the burn front under the fire are forced to pass through the flame and produce even more heat as they burn. Tuned properly, and this surely will take a little practice, the process could be fairly smokeless. This could be famous last words of course, but I think that it is very possible although the initial ignition is sure to be anything but.

The lid is put back on but is left with enough of a gap to allow combustion gasses to escape. One could also mount a chimney on the top also.

This system is simple and with a bit of experimentations can surely be made very clean burning and satisfactory. Most importantly, it is easy to maintain and operate in a back yard, burn after burn.

Once the burn front has reached the branch floor of the drum, a water hose quickly douses the fire ending the burn. It is then easy to gather the charcoal and spread it onto appropriate beds and fold it into the soil.

Undoubtedly there will be superior well engineered solutions available over time as we establish a carbon making garden culture and promote the merits of the methods. In the meantime we have this as a working method and it should be possible to run it without smoking up the neighborhood and convincing the fire department that there is a disaster in play.

Wednesday, October 3, 2007

Natural genius of Brazil's Indians

The more I discuss and pull apart the concept of the corn stover bio char production system, the more that I come to admire the achievement of these so called primitives. As my readers know, large areas of Brazil's tropical soils were made continuously fertile by the addition of many tons of low temperature charcoal or biochar per acre. This is carbon sequestration by any other name and is called terra preta.

I recognized that the only crop that lent itself easily to the charing process was corn. It produced ten tons of dry unusable waste for every acre which could produce at least a ton of char per acre. This is more than enough to visibly impact fertility. On top of that, the crop husbandry system was all about hills, so that the char was delivered directly to the hill and not to the 75% of the field kept fallow between the hills. It sounds like a basket full to me.

A review of the literature revealed that corn pollen and cassava pollen were in fact the principle crops. Cassava also produces a great deal of biomass and would nicely augment any Biochar production protocol, although I have never emphasized it.

I then recognized, from personal experience that corn had one unique characteristic that hugely accommodated the production of Biochar. Corn produces a horizontal root pad that is easily pulled out of the soil. This brick like root ball is a natural brick that permits the building of an earthen shell that could form the near vertical walls of an earthen kiln. This is hugely important, because it eliminates the need to dig a huge pit or to build a large soil bank. It can also be built anywhere and sized to the most efficient design possible.

Any piece of jungle can be burned out and with a first corn crop, terra preta can be established. Constant repetition will easily build up the carbon content to the 15% charcoal level inside a couple of generations, while preserving soil fertility.

There is also very little additional labor required, an awfully important consideration in a ulture that had no draft animals.

Once the stack is built in whatever shape works best through experience and discussed earlier, It is necessary to throw a layer of dirt on the flat top of the stack, to effect final closure. We end up with a complete dirt shell surrounding tightly packed corn stalks with a packing ratio of at least 70%.

Now comes the problem of ignition. My conjecture is that they opened a chimney in the center of the pile by pushing the dirt aside. They then dumped in a large charge of glowing coals from a wood fire held in a earthenware platter, which was then tipped over and used to cap the coals and prevent flaming. This was then covered with the displaced dirt.

And this is were the genius of the Indians really comes in. As the coal mass ate its way down through the bio mass, it drew a steady controlled stream of air in through the earthen walls and sustaining the burn. But as the burn progressed, the plate forced the process gases initially away from the chimney in back through the smoldering wall of the chimney before it finally exits through the chimney. A constant supply of fresh dirt to cover any breakouts should maintain a steady burn.

Without field trials, we seem to have a method that produces biochar by burning the process gas very completely and getting the maximum heat.

I am convinced that with a little practice, any family can produce biochar at a very high level of efficiency. This method will end slash and burn agricultural as still practiced in the tropics.

The modern farmer will want to use a closed incinerator with a double lung design to capture the maximum heat and to produce the cleanest exhaust gas. This is very capital intensive if done properly even if using the shipping container system previously aired.

I wonder what we will learn when field tests are done to compare the two systems?

All I am sure about is that the elimination of slash and burn with an annual earthen kiln system on perhaps 20% of the arable land in the tropics is a vast improvement over what passes for current practice. It will also increase the amount of continuously cropped land by orders of magnitude. To say absolutely nothing about fertility enhancement on established fields.

Traditional agriculture has beggered millions for generations. This can now change completely.

Wednesday, August 29, 2007

Methane fears

We have had a lot of enthusiasm for methane lately for its potential as a so called greenhouse gas.

http://www.physicalgeography.net/fundamentals/7a.html


Methane is a very strong greenhouse gas. Since 1750, methane concentrations in the atmosphere have increased by more than 150%. The primary sources for the additional methane added to the atmosphere (in order of importance) are: rice cultivation; domestic grazing animals; termites; landfills; coal mining; and, oil and gas extraction. Anaerobic conditions associated with rice paddy flooding results in the formation of methane gas. However, an accurate estimate of how much methane is being produced from rice paddies has been difficult to ascertain. More than 60% of all rice paddies are found in India and China where scientific data concerning emission rates are unavailable. Nevertheless, scientists believe that the contribution of rice paddies is large because this form of crop production has more than doubled since 1950. Grazing animals release methane to the environment as a result of herbaceous digestion. Some researchers believe the addition of methane from this source has more than quadrupled over the last century. Termites also release methane through similar processes. Land-use change in the tropics, due to deforestation, ranching, and farming, may be causing termite numbers to expand. If this assumption is correct, the contribution from these insects may be important. Methane is also released from landfills, coal mines, and gas and oil drilling. Landfills produce methane as organic wastes decompose over time. Coal, oil, and natural gas deposits release methane to the atmosphere when these deposits are excavated or drilled.

Table 7a-1: Average composition of the atmosphere up to an altitude of 25 km.

Gas Name

Chemical Formula

Percent Volume

Nitrogen

N2

78.08%

Oxygen

O2

20.95%

*Water

H2O

0 to 4%

Argon

Ar

0.93%

*Carbon Dioxide

CO2

0.0360%

Neon

Ne

0.0018%

Helium

He

0.0005%

*Methane

CH4

0.00017%

Hydrogen

H2

0.00005%

*Nitrous Oxide

N2O

0.00003%

*Ozone

O3

0.000004%

I want you to observe that everything in this list is at its lowest oxygenation level with the sole exception of methane. Also observe that CO2 is 200 times more available. This is true because methane is almost as good a rocket fuel as hydrogen. We usually call it natural gas when we use it to heat our homes. In fact, it is the one gas that has all the cards stacked against its survival.

Even with all the rice paddies, termites and cows hard at work producing methane and all the plants on earth consuming CO2 and nothing consuming methane except oxidizers, CO2 content exceeds CH4 content by a factor of 200.

This entry also makes the claim that since 1750, methane content has increased 150%. Who was measuring? Most certainly this has to be an educated guess linking human population growth and normal related agricultural usage to the current regime. In other words, rubbish has discovered a neat new way to produce methane.

The point is that CH4 is produced in normal biomass combustion and almost as swiftly consumed. This is not true at all for carbon dioxide.

Yesterday we addressed sustainable biochar production. Much concern was expressed over the production of combustibles like CH4 that will escape into the atmosphere. And a natural earthen field kiln will lose a lot of combustibles in this manner and not just methane. My description of the inexpensive modified incinerator design took advantage of that out gassing to fuel a second high temperature oven whose heat was then used to accelerate the carbonization process.

That solution is possibly available to industrialized agriculture. It is certainly not an option for everyone else, and may be suspect even were the equipment is available. Of course even more expensive systems can be deployed for a very small incremental gain.

The point that I want to make is that the primitive earthen kiln and my incinerator are separated only by efficiency. I would reasonably expect perhaps twice as much product to be produced. This cannot be accomplished with a sharp increase in haulage costs. I also point out that the jury is truly out as to the quality of the end product. The kiln promises to produce a more uniform end product but that may not be as advantageous.

In either case, gases are produced once a year for any plot of land and are then swiftly mopped up by the local environment.

The objective after all is to put carbon into the soil for a long time. Both these techniques do just that. The only other technique that convincingly does the same thing is the growth of new forests. Every other agricultural process that we have created is in a constant struggle to just maintain carbon content and related fertility. Terra preta promises to end this ten thousand year struggle forever.

Every subsistence farmer now has the option of either burning all his plant waste out in the open field as he has done forever, or building an earthen kiln and producing a few tons of Biochar as fertilizer for next year’s crop. He does not need a dime from his government to do this nor does he need any special equipment that he does not already have. He had no other choice before and has been the source of monster smoke clouds out of Asia’s rainforests. Now those smoke clouds can become a fraction of what they are today while he mops up the carbon for us and strengthens his farms fertility.