Tuesday, October 22, 2013

Sunlit Synergy

Sunlit Synergy

This blog is inspired by John Michael Greer’s Jan. 9th, 2013 post on The Archdruid Report in which Greer remarked that a “reader … asked what suggestions I might have if I were addressing an audience of scientists and engineers—that is, people who might be able to come up with new technologies to help cushion our species’ face-first collision with the brick wall of planetary limits. What would I want them to explore?”

He adds, “It’s a far more complex question than it might seem at first glance.  To begin with, there are at least two limits that nearly all attempts to imagine technologies for the future systematically duck. The first of those limits come out of the laws of thermodynamics, which dictate that the amount of work you can get out of any energy source is a function of the difference between the concentration of energy in that energy source and the background concentration in the environment…."

And continues, "The second limit comes out of White’s Law, which is arguably as important in human ecology as the laws of thermodynamics are in physics.  White’s Law states that the level of economic development possible in any society is determined by the amount of energy per capita at its disposal.”

Later in his post, Greer proposed a contest for his readers to offer their own suggestions. He said that, “each paper should either describe a problem that will confront the deindustrializing world in the course of the Long Descent, or propose a practical solution to some problem of this kind, or both.”

What follows is my own suggestion. It is my request to the scientists and engineers of the world. It is both a re-framing of the energy problem, and a proposed solution that still needs much research and work. I call the proposed project Sunlit Synergy.

The first thing to say is that we should perhaps re-phrase the original question in a way that doesn’t presuppose that our survival requires completely “new” technology. Many technologies have been littered alongside modern industrial society’s path of progress toward centralization and control, technologies which could be re-evaluated and could prove indispensable over time as we move away from the fossil fuel energy sources which facilitated such centralization and control.

The second thing to say is that there is no way around the fact that the ultimate energy source is the sun. And although it falls to the ground in a rather diffuse fashion, there are natural processes that lead to rather dense concentrations of this solar energy - for example, wood. Although slightly less than half as energy dense as crude oil, and nowhere near as convenient to transport, wood is a form of solid sunlight.

I’ll phrase that more positively: wood is almost half as energy dense as crude oil, and has a host of uses besides energy production, all of which produce a sizable amount of waste wood. This “waste wood” could be turned into charcoal, which could then be transformed into biochar, one of the most effective fertilizers in human history. In making charcoal, ~2/3 of the energy in the wood is released as heat, which could be used as an energy source in a host of eco-industrial processes. The charcoal, when buried, is a form of carbon that is highly stable for centuries, if not millennia. This means that almost 1/3 of the carbon dioxide that would normally get re-released back to the atmosphere through either combustion or decomposition of the wood can instead get sequestered in our farm soils.

There is, of course, an immense amount to say about the future of forestry and agriculture in this regard. And I plan on addressing those crucial pieces in the near future. But for right now, I want to focus on the technological issues surrounding our future’s energy source. So without further ado:

Sunlit Synergy
- Because wood is solid sunlight, alcohol is liquid sunlight, biogas is gaseous sunlight, biochar is sequestered sunlight, and worms enable the sunlight to be harvested in the first place.

From a few local inputs:

Non-GMO Corn from local farms; and 
Slabs, Wood Chips, and Sawdust from local sawmills,

Sunlit Synergy will produce: 

Liquid fuel (alcohol),  
Gaseous fuel (biogas), 
Livestock feed (wet distiller's grain), and 
Fertilizers (biochar and worm compost) 

in an overall process that is not only carbon neutral, but because of charcoal's stability within soils, is actually carbon negative.

Sunlit Synergy explores the potential beneficial synergistic interactions between five technologies that have been around for quite some time - wood gasification, wood distillation (pyrolysis), alcohol fuel production, biogas digestion, and vermicomposting - and investigates how arranging these five technologies in a cascading fashion, where one utilizes the available waste heat and/or waste materials from the preceding technology, can allow them to be economically deployed on a smaller, more human and community-oriented scale than ever thought imaginable.

(Definitions, summaries, and links for further information for these five technologies can be found below the following project description.)

The Plan: to build a small-scale pilot plant to serve as a "proof-of-concept", educational and R&D platform that incorporates the following:

1) A Wood Gasifier is fed wood chips from a local wood-waste stream, transforming the wood chips into wood gas which can either:  A) be burned to heat a charcoal retort, and/or B) fuel an electric generator - either an internal combustion engine or a micro-steam turbine - to produce the electricity necessary for the rest of the ecological industrial park described below

2) A Charcoal Retort is filled with slab waste from a local sawmill, and uses the heat from the wood gas to drive Wood Distillation (Pyrolysis) within the retort, transforming the slabs into charcoal, a process that itself releases even more combustible gas. This additional gas is directed to a burner placed under some type of "heat storage battery" to provide heat energy to the following process:

3) An Fuel Alcohol Still is filled with "beer" made from fermented local, non-gmo corn. This beer is distilled to 190 proof fuel alcohol with the heat from the "heat battery". Remaining heat is used to prepare the next batch of beer for fermentation. Wet distiller's grain left over from distillation is fed to dairy cows as a high-protein, high-fat, and high-fiber feed supplement for their mostly pasture-based diet.

4) A Biogas Digester is filled with any unused wet distiller's grain from the still, and any other farm wastes such as cow manure or spoiled hay, and is kept warm in the 90's F from the waste heat from the alcohol still's condenser coils.

5) A Vermicompost (worm compost) operation mixes the liquid effluent waste from the biogas digester with sawdust from the local sawmill to feed microbial populations that in turn feed worms.

Some biogas digester effluent is used to nutrient-load the charcoal. Some worm compost is used to make compost tea to inoculate the charcoal with beneficial microbes, thus transforming the charcoal into biochar.

Background Information:

Wood Gasification:         http://www.gekgasifier.com/info/intro                                         
The link above is probably the best website to explain wood gasification, although All Power Labs unfortunately placed the following words at the very beginning of the page and then never really define them: wood gas, syngas, biogas, and producer gas. So let’s quickly differentiate these terms.  It will help.

Producer gas is the gas produced by gasification, a process that transforms any solid organic matter (wood, charcoal, coal, coke, peat) into a combustible gas - primarily carbon monoxide and hydrogen - which when burned, produces an exhaust of primarily carbon dioxide and water vapor.

Wood gas is simply a type of producer gas made specifically with wood as the feedstock.

Syngas can be made from a gasifier (from any feedstock), and is similar to producer gas, except that it isn’t weakened,by nitrogen, since straight oxygen is fed into the gasifier instead of air (to eliminate the 70% nitrogen in air). FYI: 99% of the time in the modern world, syngas is not made from wood.

IMHO, biogas does not belong in the same category as the above gases, but is made from an entirely different process – the anaerobic biological decomposition of organic matter. This produces mostly methane and ethane, which is essentially similar to “natural gas”- a fossil fuel.

Wood Distillation (Pyrolysis) in Retorts for charcoal production for biochar:
A retort is simply a fancy word for a mostly sealed metal or masonry container – filled with wood, and heated from an exterior source to transform the wood, through pyrolysis, into charcoal and a combustible gas. Pyrolysis literally means “breaking apart with heat”.

The combustible gas coming out of a retort is also called syngas. Whereas a gasifier needs to pull in enough oxygen to fuel enough combustion to create the heat for pyrolysis to create either producer gas or syngas, a retort has heat added from an exterior source for pyrolysis to create syngas Pyrolysis can either refer to one part of the process that occurs within a gasifier, or it can refer to the entire process that occurs within a retort.                                                                                       

So, in summary, wood gasification provides its own heat by combusting a small percentage of its fuel, and transforms its remaining fuel into heat, combustible gases and ash. Whereas wood distillation (pyrolysis) does not provide its own heat, and transforms its fuel into combustible gases and charcoal.

Wood distillation was the term used in the old industry and literature, while pyrolysis is the term used in the modern industry and literature.

FYI: For gasifier geeks: wood gasifiers can be designed and operated to turn their fuel into charcoal as well, and not just ash. But for the purposes of this project, we’ll be assuming the gasifier is not producing any charcoal, but only ash. In this project, it will be the retort that produces the charcoal. This design allows the use of less-processed wood wastes (slabs vs. wood chips), and also allows the concentrated capture and combustion of the gas created by the charcoal production in order to facilitate the alcohol production.

As can be seen by even a quick glance at Max Klar’s 1920 book The Technology of Wood Distillation, with Special Reference to the Methods of Obtaining the Intermediate and Finished Products from the Primary Distillate, one can gain quite an insight into how sophisticated and evolved the technology was of making charcoal in retorts before the petrochemical age squashed this industry like a bug.

This book is available digitally at:              http://archive.org/details/technologyofwood00klaruoft
And is available, amazingly enough, in physical book form at: http://www.abebooks.com/servlet/SearchResults?sts=t&tn=The+Technology+of+Wood+Distillation

Unknown in 1920, when Max Klar wrote the above mentioned book, was the incredible potential for another use of the charcoal - biochar.

I highly recommend checking out how the indigenous Amazonians transformed large tracts of some of the world’s worst soil into some its most fertile, by incorporating biochar into their soils. Those “Terra Preta” soils (literally, “dark earth”) are often literally mined for their fertility, and continue to hold on to the great majority of that carbon originally sequestered so many centuries ago. The indigenous Amazonians were apparently making charcoal and then burying it in their midden piles to load it with nutrients and beneficial microorganisms, and then burying the resulting bio-char into their farm fields.

A quick overview of the discovery of biochar can be had by watching the hour-long free BBC documentary, “The Secrets of El Dorado”, available here:    http://www.youtube.com/watch?v=0Os-ujelkgw

What’s incredibly important to note is that charcoal production produces dramatically more heat than it requires. Now, this isn’t some violation of the Second Law of Thermodynamics. It’s just that wood is solid sunlight, and pyrolysis releases much of that stored sunlight in the form of combustible volatile compounds. A 55 gallon barrel full of wood chips transformed into charcoal releases a net 250,000 BTUs of heat. Wood, although not nearly as convenient and transportable as petroleum or natural gas, is a very concentrated form of energy.

My recommendation would be to utilize an “Adam’s Retort” type design, to be able to utilize less-processed wood wastes, such as slab and edger waste from small, local sawmill operations – as opposed to many biochar retort designs that require more processed wood waste, such as wood chips. Bob Wells of New England Biochar seems to now offer the most cutting edge types of designs for these here in North America.

I recommend utilizing the waste heat from the retort to heat some type of "heat storage battery" to allow the harnessing of a very crude and basically uncontrollable form of energy – the intense heat that comes from burning the gases blasting out of the retort – into a form that allows the fine temperature control necessary to run an alcohol still.

Presently, I propose using a large super-insulated tank of waste fryer oil as the “heat battery”. Although it has ½ the specific heat of water, oil avoids the dangers of having a vessel of pressurized steam, and can be taken to twice the temperature of water. This would only work on a very small scale as proposed in the pilot project. Otherwise, pressurized steam would likely need to be used as the "heat battery".

To utilize the heat in the oil, a coil of copper pipe is installed inside the tank of oil, and has an open end that leaves the tank and enters the body of the alcohol still. When the still needs more heat, a valve can be opened to run small amounts of water through the coil, transforming the water into steam - immediately dumping the steam’s heat into the still without any build-up of pressure.

Small Scale Alcohol Fuel Production:
Alcohol fuel production often gets such a bad rap in our culture that I want to take a moment to address its two biggest criticisms. It is often noted how much energy it takes to make. There’s more to say about all of this than I have room for here, so I highly recommend checking out David Blume’s book, Alcohol Can be a Gas, and particularly its “Appendix A, Ethanol and EROEI: how the debate has been dominated by one view”. ("EROEI" stands for Energy Returned on Energy Invested)

Suffice it for now to say that I propose to utilize only the waste energy created by transforming waste wood into biochar as the energy input for the alcohol production. On top of that, this system would require dramatically less energy than is conventionally required to produce alcohol fuel since 1) we would only make 190 proof alcohol, instead of attempting to make 200 proof alcohol (see David Blume’s book again for more information on this), and 2) more importantly, we would not be drying down the waste products from alcohol production (the distiller’s grain), but would be utilizing it wet by feeding it straight to livestock, or by feeding it into a methane digester. Both of these design features allow the use of significantly less energy inputs.

The second big criticism of alcohol production is that it somehow competes with food production. But in the U.S., the biggest alcohol crop is corn. Only a scant percentage of corn gets used directly for human food, but is mostly fed to animals, and of that, mostly to cows. But cows could produce more human food if fed the waste products of corn alcohol production, than if fed straight corn. This is because the sugar and starch in corn interferes with cow’s natural digestive processes. Alcohol production removes the harmful sugar and starch from the corn, but leaves and actually improves the remaining proteins, vitamin complexes, and fats.

Any extra wet distiller’s grain not eaten by the cows will be sent to a methane digester, along with any other farm wastes such as cow manure and spoiled hay. At this point, the energy in the starches and sugars in the crop have been removed by the yeast and have been transformed into alcohol - liquid sunlight. Now it’s time to remove the energy left in the proteins, fats, and fibers that remain in the crop and transform them into gaseous sunlight.

Methane Digestion:
In temperate climates, methane digesters need to have their temperature maintained in the 90s F, but this could easily be done with stored waste heat from the alcohol still’s condenser coils. The methane digester produces biogas - gaseous sunlight - and gets most of the remaining carbon energy out of the crop, so what remains now is liquid nutrient effluent.

Some of the effluent will be used to nutrient-load the charcoal. Charcoal has an incredible amount of tiny pores throughout its structure. The walls of these pores are all chemically adsorptive, and soak up much of the liquid nutrient.

The rest of the effluent is added to sawdust from the local sawmill. The effluent is, once again, liquid nutrient. The sawdust is almost straight carbon. Together they are the perfect workable substrate for feeding microbial populations that will feed worms for making worm compost.

Some of the worm compost will be used to make compost tea. After soaking the nutrient loaded charcoal in compost tea, we now have biochar. Charcoal is like a deluxe motel for beneficial microorganisms, and if you haven’t heard of the Soil Food Web, and how critical beneficial soil microbes are for soil fertility, then I recommend checking that out too. It is unbelievably important. Really. It deserves a whole post of its own.

So once again, from a few local inputs – non-gmo corn from local farms; and slabs, wood chips, and sawdust from local sawmills – Sunlit Synergy will produce: a liquid fuel (alcohol), a gaseous fuel (biogas), livestock feed (wet distiller's grain), and fertilizers (biochar and worm compost) in an overall process that is not only carbon neutral, but because of charcoal's stability within soils, is actually carbon negative.  

Sunlit Synergy will provide concentrated energy and fertility for our future – not to replace the immense quantities of fossil fuels that now support our modern lifestyles, but that can support a complex, yet sane society connected to the source of its life in gratitude.

Yes yes.

Thanks for your time and attention.