Saturday, March 24, 2012

Is Urea the Best Storage Medium for Hydrogen?

With all the issue of storing hydrogen and the need for other transportation fuel options, urea is getting a few strong looks. Urea was the first natural compound synthesized. Urea is an organic compound with two HNH chains connected to a single CO molecule. That gives urea a reasonable hydrogen density in a stable and common compound.

There are a variety of uses for Urea, one of the more important is as a fertilizer. With methane or syngas as a feed stock, Urea is produced using nitrogen in the air. Since syngas can be produced through a variety of fuels including, bio-mass, coal, natural gas, petroleum and even alcohols, feed stocks are not difficult to come by. In a pinch, urea can even be produced with electrolized hydrogen and air. There is also of course natural urine from mammals.

Urea can be separated in solution into ammonia which can be used in internal combustion engines with an energy density of about half of diesel fuel. In an alkaline fuel cell, urea is more easily split into the hydrogen gas needed for our hydrogen economy.

Because of the non-hydrogen components, in the alkaline fuel cell potassium carbonate is a by produce which has uses of it own. If urea is used as a primary fuel storage medium, there would likely be an over abundance of potassium carbonate which would have to be dealt with.

With a two stage electrolysis process, converting the urea to hydrogen and potassium carbonate and then the hydrogen to energy and water, the overall efficiency would be reduced and complexity of the system would be increased. That will require more research, but there is some promise.

Another down side is urea and nitric acid can be used to make some pretty impressive explosives. Just about any energy source can be used to make a big bang, but in our terror filled world, someone will probably make and issue of the obvious.

The biggest advantage is that urea could be used in most gasoline, gas turbine and diesel engines while hydrogen fuel cell or direct ammonia fuels cell costs are brought down to more competitive levels.

Another advantage is in the production process. As a common component in fertilizer, urea, potassium carbonate and charcoal combined make an excellent soil conditioner and CO2 sequestration method. Since potassium carbonate is alkaline, it would be most useful in sandy soils that are typically acidic. An important consideration when agricultural soils tend to degrade with time. With additional hydrogen provided by high temperature electrolysis or even less efficient direct electrolysis from water, the total product chain could be profitable and beneficial.

Urea in crystalline form is not a requirement for the ammonia processes, it does though provide simple storage for easy transportation. Where pipeline infrastructure is available, ammonia would likely be a lower cost alternative. In either case, Urea and/or ammonia have serious potential as a transportation energy staple.

Monday, January 9, 2012

Did the EPA Give us Coal for Christmas?

Just before Christmas of the past year, the EPA announced with a certain amount of political pomp and circumstance, that the new Mercury and Air Toxin Standards MATS for fossil fuel users. The standard is based on the top 12 percent of coal power plants which will put about 10 percent of older coal plants out of business and require the remaining plants to retrofit to meet the standard or switch to another fuel likely natural gas. 25megaWatts is the minimum size plant that the standards apply. A possibly unintended consequence, it that the standards may very well have an equal or strong impact on cleaning up the renewable energy sector, biomass in particular.

Coal got its toxins from the biomass that became coal of millions of years. Depending on the growing conditions, renewable biomass can contain a significant, at least with respect to MATS, amount of toxins. The range of Mercury content varies and I have not seen a complete study of biomass Mercury content, but 0.026 micrograms per gram, the average for dried peach leaves, is a fair estimate for biomass grown in the marsh or swampy location typical of timber products. Timber products tend to promote swampy conditions, which is an important factor in maintaining water shed efficiency.

Of course, the Mercury content in coal is not listed in micrograms per gram, that would be too simple, coal is listed in grams per ton, short ton in the United States. There are 907184.7 grams per short ton and average quality coal contains about 0.1 grams per short ton. That converts to 0.11 micrograms of Mercury to gram of coal versus 0.026 for dried peach leaves. So the Mercury in peach leaves is much less than the Mercury is coal right?

Well, so is the energy content. Coal has 28 Mj/kg while peach leaves, which I would estimate to be about the same as switch grass or wood products, has about 5Mj/kg wet. It takes energy to dry stuff and if you use enough you can convert that switch grass or wood to charcoal or biopellets for a wood stove. If you adjust the Mercury content of the peach leaves to allow for the energy difference, Peaches leaves would produce 0.146 micrograms of Mercury per equivalent coal gram of energy. That by the way does not include the differing amount of energy required to dry to biomass for use as a fuel.

This would tend to reinforce my suggestion of Coal/Biomass co-generation as a responsible use of existing resources and the reduction of the massive mountains of waste buried all across our great nation.

I am sure though, that there must be a warm and fuzzy reason to regulate this crazy idea into oblivion.

Sunday, December 25, 2011

Optimism for Christmas - A grand Gift

Most of the energy issues that face our world are repairable in proper steps. All it takes is optimism and intelligence. I have been worried for some time because the pessimists have been in charge.

There is a fine line between optimism and pessimism, which is called realism. Nothing good results from too much of any of them, even realism. Even a realist needs a little craziness from time to time.

Municipal scale cooperative utilities are my crazy vision of the future. Combining power generation, waste disposal, water treatment and production in efficient co-generation to get the maximum benefit for the community for the buck.

No more NIMBY mentality. Deal with your own shit on your own turf. The technology is available now to start on that path. There are lots of great ideas that have waited for their time. Which ones will win depends on the needs and desires of the community.

So I will be digging through some of the better ones I have and add a few of my own not that it looks like the rough patch is getting shorter.

Happy Holidays and a prosperous future.

Saturday, December 24, 2011

What Just Happened? Is Hydrogen Back in the Picture?

The EPA made a politically timed announcement that the Maximum Achievable Clean Technology (MACT) is now in force in the the United States. Under the guise of getting Mercury pollution from nasty coal fired power plants finally under control, the MACT will have impact on about 10 percent of the older coal power plants with 12 percent of the currently operating power plants already meeting the MACT tighter standards. While the Greens strut around proclaiming victory over nasty coal, the MACT seems to endorse clean coal technology, or cleaner coal technology if you prefer.

As usual, the industries that will bear the brunt of the regulation will not be the target mentioned in the media hype. Forestry and pulp products, smaller scale industrial power generation and institutional (university and military) power and thermal plants will have to get out of the power business.

Pulp mills have worked hard the past 20 years to bring emissions under control to meet the demands of encroaching residential property owners that build homes near pulp plants. Hey, the land was cheap for a reason guys.

It is all good, other than the suburban sprawl started the ball rolling. Cleaner emissions generally mean more efficient energy use.

Integrated Gasification combined cycle power generation, the cleaner coal technology, meets the EPA regulations which opens the door to a variety of mixed fuel and synergistic industrial applications. Only problem is, will the small guys feel the boot of big government and be driven out of the picture?

I haven't posted on this blog in quite some time because nothing has happened. MACT may be a big something. With some reasonable assurance that the rules are not going to change for the 50 years or so required to invest in new coal and unconventional fuel technology, the EPA may have unleashed the innovative potential of American entrepreneurs. The tide may have turned!

Monday, October 24, 2011

Simple Versus Too Simple

Making the complex simple to understand is the goal of science, any discipline really. That goal often requires compromises where one portion of the overall concept is attempted to be explained by analogy to a commonly understood concept.

Physics uses many basic analogies, Carnot Engines, Equilibrium and adiabatic processes, as foundations even though none may ever exist. They are convenient models of perfection for comparison.
In atmospheric physics, the dry adiabatic lapse rate, where temperature changes with pressure with no gain or loss to the system, is an example of an equilibrium state with prefect energy transfer, a Carnot engine. Perfection does not exist in nature, it can only be approached.

The dry adiabatic lapse rate in Earth’s atmosphere is the combination of the surface temperature, the composition of the gases in the atmosphere, the molecular weight of the gases, the thermal properties of the gases, the gravitational constant and radiant energy interaction with the changing density and composition of gases compressed by gravity. A rather complicated process we on the surface take for granted.

If you are in favor of electrical analogies, the adiabatic lapse rate is an inductive load with a steady state current. Small changes in current are dampen by properties of the inductor and rapid change produces huge changes in the potential energy or electromotive force realized across the inductive load.

The electromotive force is provided not by a single source, but several, a conductive battery, a latent battery, a gravitational battery and a radiant battery are the more significant power sources.

The radiant battery is both solar and black body, with cells poorly designed for the task, but adequate in steady sate conditions. In steady state, the potential can be determined at different points in the atmospheric circuitry and the total accurately calculated from one connection to the next. i.e. if we know the voltage and current into a black box and the current and voltage out of that black box, we can determine to a point what circuitry is in the box. With more than one condition, we can better describe the inner circuitry.

The currents are in parallel from the electromotive sources at the surface, Fc, Fl, Fr, and F?, for conductive, latent, radiant and the question mark is ever present uncertainty. Each of the batteries providing these currents or fluxes, have cells, Fra, Frb, Frc …Frn, for example. The subscript letters can be individual wavelengths, associated energies, or combinations of wavelengths and energies that impact portions of the atmosphere.

This is the simplicity of the Kimoto equation, dF/dT=4(aFc+bFl+cFr+…F?)/T, which is derived from Stefan’s equation, Fi/Fo=alpha(Ti)^4/alpha(To)^4, or the change in energy flux of a body is proportional to the change in temperature of the body at initial temperature T. All the coefficients, a,b,..n, represent changes to the flux through the atmospheric inductor or impedance.

Proper use of this simple equation requires, proper consideration of the flux values and ever present uncertainty.

Sunday, October 23, 2011

New Blog For Easier Navigation

This has been my trash blog for a long time. Random thoughts on random subjects. For the Climate Change crowd, I have started a new blog to try and better organize things. You need to have a common starting point to see how a complex set of feedbacks and natural responses combine into a very interesting balance.

The New Blog, CaptDallas' Redneck Theoretical Physics Forum. There is quite a bit of pun intended in the title and the attitude. The curious may find it interesting.

For the insomniacs in the crowd, The Energy Budget of the Polar Atmosphere in MERRA is a nice light read. There are pretty significant descrepancies that more than cover the conductive issue I am trying to quantify. The devil is in the details, but adapting the equation should shed some light on the issue. Poor satellite coverage is not helping at all. There is a significant lead in surface change over down welling change though that is interesting.

Saturday, October 22, 2011

Carbon Dioxide- A Not so Well Mixed Gas

In an atmosphere without significant water, carbon dioxide would be a very well mixed gas. Earth’s atmosphere has water in all phases and at different concentrations. This greatly complicates solutions for the changes in relative conductive and radiant properties of the atmosphere.

Carbon dioxide rains out in areas with high humidity and precipitation. The rate of diffusion varies with temperature and pressure from well mixed gas ratio to regions where CO2 is depleted via rain out. Using global averages provides good results, but for regional evaluation, the changes and rates of change in CO2 must be considered.

The Antarctic with its low precipitation rate and very cold climate offers a baseline for CO2 change in the overall atmosphere. It is in the Antarctic where the impact of CO2 on conductive flux is most evident and the impact on radiant flux more over estimated. The blend of underestimated conductive change and over-estimated radiant change are uniquely Antarctic.

While theories are plentiful, the reality is hard to determine. Sublimation cannot be completely ruled out on a microscopic scale, due to conditions available between the Antarctic Tropopause and the surface temperatures and pressures.

The exact psychometric relationships will require a great deal of further study. However, as tropospheric temperatures can approach -95C and the temperature and pressures of the Antarctic can be less than -60C at 1020mb, microscopic sublimation is possible provided a deposition substrate of a few atoms can be found. Microscopic carbonic snow, an interesting theory for idle moments.

Carbon dioxide concentration lags between Antarctic and Mona Loa would be much more easily analyzed.'

With a reliable estimate of the changes in carbon dioxide change, the Poisson Equation can be adjusted to the specified thermal properties of the atmosphere regionally, adding greatly to the utility of the Kimoto equation.