Industrial Ferments on Farms
Wales and Eire are rainy places best suited for grassland to pasture ruminant beasts and horses — such is the tradition. However, this could change to biofuel production by way of fermenting other plantstuff grown there instead.
The transition away from burning fossil fuels opens an opportunity for changing the agriculture of such damp places as these. Traditional pasture could give way to other plants that produce far more dry matter per unit of area, plants the livestock normally raised there will not eat.
Liquid fuels for transport vehicles are the biofuels I speak of, though not ethanol, for it is not a good engine fuel itself. ..In combination perhaps, but alone it lacks energy density per litre. Needed at this time are biofuels more energy dense and blendable in all proportions with gasoline, ones that may be used in today’s cars. ..A near future switch to EC engines (external combustion) would be most welcome.
Farm production is dealt with later in this piece, but first…
Road Vehicles
All~electrics using batteries to store electricity may seem the future of road travel, at least for personal passenger vehicles and light delivery vehicles in urban areas. _Yet, the future has often previously failed to unfold as many had anticipated. And today it might not either. ..There exist, after all, certain inconveniences with any all~electric vehicle — sufficient to give a person pause. Electricity grids do get knocked out by severe storms.
The issue is with the batteries, which still cost alot, weigh alot, and perhaps will not age well, carrying less charge than they did when new. ..Using only fast charging is very likely to to affect battery performance over time, so their replacement might be required sooner than expected. ..That changes the cost of owning an electric vehicle. ..Yet, fast charging is what users much prefer, while range between recharges is another area in which current all~electric vehicles fail to sparkle. (Toyota might have a much better battery for this soon.)
While future improvements in batteries for road vehicles are eagerly anticipated, they do seem a long time coming. Moreover, and rather ironically, any such improvement should benefit hybrid electric vehicles more so than the all~electrics. ..After all, hybrid electrics have far fewer batteries onboard, often no more than a fifth as many. So when the cost of batteries comes down, the overall cost of hybrids will approach than of non~electric vehicles, whereas the all~electric, having so many more batteries will still be higher in price to buyers.
Even worse for the proponents of an all~electric future, there exists great potential for improvements in hybrid vehicles, including also for heavier vehicles.
Future Hybrid Electrics
Technically, a hybrid vehicle has two sources of power to propel it: _a combustion engine and a store of energy in some form. For a hybrid electric that store is in electric batteries that can be drawn upon to run an electric motor or motors to turn the wheels.
The combustion engine is not meant to idle, as this wastes fuel. ..Ideally, either the engine is fully on, else off. And when on, it is running an electrical generator whose output is either going to the motors or the store. This arrangement has the engine running at near its peak efficiency in fuel use.
When the batteries are about fully charged, the combustion engine shuts off and the vehicle is moved by electricity coming from the batteries alone. When at rest in this state, no energy is being used — at least, none to move the vehicle. So a hybrid gets excellent fuel economy in litres consumed for the distance travelled.
Rather oddly, vehicle makers have little bothered with what type of engine best matches this duty cycle. They simply installed the types of engines they have always used: internal combustion [IC] engines running on gasoline.
For multiple reasons, external combustion [EC] engines running on fuels cheaper than gasoline appear far more suitable. ..Indeed, all hybrid vehicles should have been sporting such EC engines long since.
EC Engines
There are several types of external combustion [EC] engines, but I’ll concentrate on a turbine running within a closed loop, in which the working fluid goes from boiler to turbine, to condenser, and back to the boiler, round and round. ..Such an engine may be heat efficient in use of fuel when running near its maximum power output, though that does fall off pretty sharply at partial loads.
But then, in a hybrid vehicle it would be at full output, else shut off, so it should provide good fuel efficiency. ..Also, it is a simpler engine to manufacture, so should cost less. Plus, it is fuel flexible, as all types of EC engine are, due to the fuel being burnt in open air. ..This also results in better emissions, similar to what a furnace burning a liquid fuel to heat a building has. Thus healthier air to breathe, a boon for urban dwellers especially.
This flexibility is a considerable advantage, since fuels that cost less may be used, and locally made instead of imported, an important consideration in respect of many a country’s balance of trade. ..Not to overlook the political advantage of job creation in making such fuels. Biofuels displacing fossil fuels also help make meeting COO emissions targets much easier. (Yes, that is CO2 merely written differently.)
In short, there are multiple benefits to EC engines — to the vehicle makers in lower costs; ..for their buyers in lower purchase prices and lower fuel expense; ..to urban communities in cleaner air, hence better health; ..to the goal of moving away from fossil fuels; ..together with local job creation in making biofuels, and therefore fodder for political advantage.
Biofuels for Today
However, what is needed for existing cars, including most hybrid electrics, are biofuels blendable with gasoline in any proportion. ..While methanol or ethanol are blended with gasoline in many places, their proportion is usually low. Higher alcohols such as butanols, pentanols and hexanols are better for blending and also are more energy dense.
Likely the best way to make these higher alcohols is via hydrogenation of their esters. As instance, an ester made by combining ethanol with butanoic acid will add hydrogen to yield butanol and ethanol. ..Which is to say, the acid becomes an alcohol in this way, so the alcohol used to make the ester may be recycled. ..Here, a good choice is 1~propanol, since the relevant esters are practically insoluble in water and thus readily isolated.
An acids ferment is much simpler than trying for an alcohol, and the ester making step should be easy enough. Also, mixed acids won’t matter*, since they simply lead to a mix of alcohols, which as a group should readily blend with gasoline and possess an energy density not greatly different than gasoline. The hydrogen required could be got by some sort of electrolysis, or in some other manner.
Another means of obtaining a fuel alcohol is by way of a ketone. As instance, acetone when hydrogenated yields 2~propanol (isopropyl alcohol) which is familiar as a disinfectant. Some reading this will also be familiar with butanone, a solvent commonly known as MEK [methyl.ethyl.ketone]. Upon adding hydrogen it becomes 2~butanol.
(CH3)2CO + H2 –> (CH3)2CHOH ___is acetone to 2~propanol.
Both these ketones may come from ferments somewhat indirectly. The acetone is produced by certain bacteria from two molecules of acetic acid. (*Excess acetic acid from above may be dealt with here.) ..This process in the research stage has been made with thermophilic bacteria modified to suit, even running above 60 degrees C which is above the distilling point for acetone, so it escapes as vapour. Very easy separation of product.
The butanone comes via a different route, from 2,3~butanediol over an acid catalyst, the diol being a ferment product readily produced. Several different bacteria produce it, some dangerous to use, others perfectly safe. ..Some can utilise a wide selection of starting material. The relevant genetic bits responsible have been put into a yeast, which would be more convenient to use than bacteria
Joined Together
Another way to make a fuel out of a ketone is by combining it with two alcohols in an equilibrium reaction over an acidic resin or solid acid as catalyst. [Newer catalysts may well be better.] As instance, acetone plus two ethanols:
(CH3)2CO + 2 EtOH –> (CH3)2C(OEt)2 + HOH
That product is di.ethoxy.propane which mostly separates from the water, and must then be made anhydrous. It is a good gasoline component. Butanone may be used instead of acetone.
By the same procedure a different gasoline component may be made by combining butanone with one molecule of butanediol to form a cyclic di.ether that has 3.C and 2.O atoms in the ring and methyls plus an ethyl attached where one would expect (if one were a chemist). It is 8C.16H.2O while ethanol is 2C.16H.O.
Naturally, the range of possible biofuels is much broader for open air combustion such as with an EC engine. ..Other means than fermenting may instead be used to obtain some of them. ..As well, these may replace fossil fuel oil wherever it is being used in furnaces for heating buildings.
Farm Production
Pasture is for livestock, and pasture grasses are not likely the best choice for producing large amounts of fermentable material. In a climate as wet as that of Eire and Wales, reeds or sedges grown in shallow standing water could yield perhaps ten times as much dry matter per unit of area. ..This material would be chopped and fermented.
Bulrushes, also called cattails, (Typha latifolia) can be very productive perennials, and not affected by disease. ..They may be grown in shallow swales or ditches following the contour of the land and divided into shortish linear segments by fill. ..Since they grow fairly tall, separating parallel strips of them would be best for growth and ease of harvest.
Organic Acids Production
This is a ferment controlled solely by the conditions under which it takes place. In this respect it is similar to ensiling, though the objective here is not preservation of the material but instead ongoing acids production.**
To facilitate this, the heaped material will be very wet and thus anaerobic, so the chop can be much coarser than is used for ensiling. This permits use of simpler equipment in the field and considerably less fuel.
Because accumulated acids would stop the ferment, these must be removed periodically or continuously. Dripping water on the top of the heaped material accomplishes this as it percolates down through the heap. Which slowly shrinks as the plantstuff is turned into organic acids.
The amount of water applied is adjusted so as to have a set pH of what seeps out the bottom. As well, conditions must be such that methane production does not occur, even though the bacteria that convert acetic acid into methane are present.
The seepage will have only a small percentage of acids in it (rather like vinegar) so some means of extracting these is needed. Various approaches are possible, and competing methods will no doubt arise. Ingenuity in this regard is to be expected.
What leaves the farm for a processing centre would most likely be be a mix of organic acids — possibly in a solvent, or attached to some material such as activated charcoal or some type of resin; or perhaps instead as a salt. There they would be transformed into a biofuel. _Alternatively, what leaves the farm for the processor may be butanediol.
___**note: Including an ethanol producer such as Zymobacter palmae results in longer acids being made by other bacteria, which use the ethanol in doing so. Alternatively, the water trickled through the pile may have some ethanol in it, producing the same effect down the pile.
from the website… regionalseats.ca/wp/