Showing posts with label methane. Show all posts
Showing posts with label methane. Show all posts

Thursday, September 13, 2007

Cattle Methane Production

The news is alive today with an report by some chap who has chosen to warn the world that the large global herd of cattle are on the way to distorting the global climate through the greenhouse effect of methane. I have already pointed out that this concern is at best rubbish in other posts and is like been concerned that the excessive production of rainfall will increase the sea level.

All methane departs for the vast ocean of the troposphere were it is vigorously consumed, well outside the working atmosphere. That any remains for any length of time at all is only due to strong continual point sources. The methane map over the oceans show an unchanging barrenness, which confirms the rapid rise of methane through the atmosphere.

I am growing rather weary of scientists acting like stock promoters hustling the new theory of the day. At least stock promoters make no claim to intellectual authority. Yes Virginia, I is a stock promoter in other lives and fully appreciate the application of nuanced presentation to keep the boys out of jail.

At least cows are not producing a like amount of CO2. An appropriate question to ask is if the original ecology maintained the same level of ruminants. This certainly was true on the buffalo commons of the great plains. It must have been also true in all of Asia and Europe. There are huge tracts there that would clearly benefit from the reintroduction of bison.

The reforestation of the Sahara will go hand in hand with the introduction of cattle to process and refertilize the ground cover that will be reestablishing itself. This will be the first major step in terra forming the earth as all hot dry lands are retimbered with the technical assist of atmospheric water harvesting.

Off course, I am quite sure that that fine gentleman also subscribes to the argument that the global population needs to be sharply reduced. At least his argument for the sharp reduction in cattle herds is leading there. None have yet shown the required leadership to show the rest of us the required method.

Readers may wish to go back and read my early posts on the use of atmospheric water recovery.

Friday, August 31, 2007

Methane and pottery

In the end concerns over methane production are irrelevant. We have doubled production in the last century and it is all gone. The reason is ultimately very simple. It migrates to the upper atmosphere and is consumed. This is something that is not an option for CO2.

Does the sharp increase in methane reaching the troposphere have any effect whatsoever? The quick answer is nothing that is obvious. It is a little like measuring the effect of the Mississippi on the Atlantic. The practical answer as always is to make as much as you desire and see were it takes you. My guess is nowhere.

That means that methane production concerns regarding all forms of biowaste combustion are misplaced. My real concern would be for well intentioned government regulation been actively imposed forcing a larger industrial price for the use of the method.

The second issue that has attracted comment is the association of pottery shards in the terra preta soils. I naturally postulated that this was partly to do with the disposal of kitchen waste in the corn stover stack kilns as we described in earlier postings in July. I also realized that a large bowl would have to be used to transport hot coals to the top of the stack and perhaps dumped into a prepared chimney.

These bowls are as primitive as you can get and very prone to heat breakage, so the presence of pottery is no surprise. My discomfort came from the fact that they would have normally taken broken pottery away with them for disposal elsewhere. So why not?

The answer came to me this morning. It is natural to take the bowl of coals to the top of the stack and to dump them there in the center and to let the coals slowly burn out a chimney. The problem is that you have to cover these coals with dirt to prevent flame out. The best way to do that is to upend the bowl on top of the coals and to throw dirt on top of that. Otherwise, the coals will end up been smothered by the dirt. The bowl would then migrate slowly to the bottom of the stack. In the process the high heat would cause this low quality pottery to breakup into very small pieces not worth recovering or causing any difficulty for cultivation.

Actually a pretty nifty solution to the problem of controlling the ignition coal mass. While this was progressing, the farmer would stand by to throw dirt on any emerging openings in the stack to prevent a flare up.

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.