Introducing a simple, renewable chemical to the pretreatment step can finally make biofuel production both cost-effective and carbon neutral:
Lignin is one of the main components of plant cell walls. It provides plants with greater structural integrity and resiliency from microbial attacks. However, these natural properties of lignin also make it difficult to extract and utilize from the plant matter, also known as biomass.
[…]
To overcome the lignin hurdle, [UC Riverside Associate Research Professor Charles] Cai invented CELF, which stands for co-solvent enhanced lignocellulosic fractionation. It is an innovative biomass pretreatment technology.
“CELF uses tetrahydrofuran or THF to supplement water and dilute acid during biomass pretreatment. It improves overall efficiency and adds lignin extraction capabilities,” Cai said. “Best of all, THF itself can be made from biomass sugars.”
[…]
First-generation biofuel operations use food crops like corn, soy, and sugarcane as raw materials, or feedstocks. Because these feedstocks divert land and water away from food production, using them for biofuels is not ideal.
Second-generation operations use non-edible plant biomass as feedstocks. An example of biomass feedstocks includes wood residues from milling operations, sugarcane bagasse, or corn stover, all of which are abundant low-cost byproducts of forestry and agricultural operations.
According to the Department of Energy, up to a billion tons per year of biomass could be made available for the manufacture of biofuels and bioproducts in the US alone, capable of displacing 30% of our petroleum consumption while also creating new domestic jobs.
Because a CELF biorefinery can more fully utilize plant matter than earlier second-generation methods, the researchers found that a heavier, denser feedstock like hardwood poplar is preferable over less carbon-dense corn stover for yielding greater economic and environmental benefits.
Using poplar in a CELF biorefinery, the researchers demonstrate that sustainable aviation fuel could be made at a break-even price as low as $3.15 per gallon of gasoline equivalent. The current average cost for a gallon of jet fuel in the U.S. is $5.96.
That approach seems like hype to me. For one thing, THF is not cheap, quite volatile like a lot of light ethers, hazardous, and tends to form peroxides which is why it ships pure with few hundred parts per million BHT or something similar. Anyone who has tried to oxidize it to GBL knows it can be tricky to deal with. It’s a favorite around the chem lab, sure, but there are a lot of other better candidates to treat biomass.
If you ou do a Google Scholar search for “lignin” you’ll see countless papers over generations of people trying to deal with this problem (similar in fame as trying to deal with, manipulate, or find uses for chitosan). It is hard because it is the evolved solution to the arms race of decomposing organisms trying their best to break it down fast, with feasible energy expenditure, and with chemicals that are compatible with sustaining biological conditions. If nature can’t do it well enough to suit our purposes, odds are we can’t either, and if you are going to embrace chemically harsh conditions then you might as well go all the way.
“Biofuel operations” can be boiled down to “solar-ray farming”. What is any given method’s net energy yield per annual sunlight exposure per square meter?
Biofuel = no food = famine + you will have not even famine bread and be happy because my tank is green.
It’s ludicrous to trust these people at this point. Same with the sudden love of nuclear power. It boils down to hatred of people and the desire to be rid of most of them.
At first glance this seems like a more sustainable, environmentally friendly energy source for vehicles and whatnot than the batteries used in EV’s.
It will be interesting to see if the elite start touting this, leaving EV owners in the lurch like everyone who swapped their incandescent bulbs for compact fluorescents, only to be told that we should be using LEDs instead.
At a conference on ethanol I attended a few years ago, the presenter was queried regarding the overall thermodynamic efficiency of the process. He refused to answer the question posed, and instead insisted that the distillation stage was a net positive energy gain, which is probably true. But the overall net energy must be negative, as is almost all “renewable” energy “sources.”
“Creating jobs” is a tell.
“At a conference on ethanol I attended a few years ago, the presenter was queried regarding the overall thermodynamic efficiency of the process.”
I don’t know much about thermodynamic efficiency, but I have heard of EROEI — energy returned on energy invested. If a power company has good EROEI, that is probably where the debate should start. However, some necessary companies are going to lose energy and that is okay. We accumulate energy sources so that we can use energy as physical work.
If at site X the managers must spend three barrels of refined oil to pump enough crude to make just one barrel of refined oil, then site X is not very promising. If, however, there is some weird source of energy that is normally not very good — e.g. intermittent solar power — and that can pump out the crude — then site X might be able to limp along for a few more years.
A different problem is how to claw back some useful energy from processes that are not primarily centered on energy production. For example, humans need food and humans must dispose of the farm waste inevitably resulting from food production. Sometimes that farm waste is a profitable energy source, and sometimes it is not. Biofuels are a good idea, IMHO, because farm companies have to spend money to handle garbage somehow.
Example from 2016:
Is the EROEI good for generating electricity from cow dung? Maybe, maybe not. But as long as we eat cow meat, we are going to have to process the cow dung somehow, and we might as well process it in a way that claws back some useful energy.
Getting back on topic:
“To overcome the lignin hurdle, Cai invented CELF, which stands for co-solvent enhanced lignocellulosic fractionation.”
I am sure CELF is carbon-neutral. I am not a global climate crisis panic-monger, though, so I am not very worried or very excited about carbon-neutral technologies. I would be very interested in CELF companies if they could show good EROEI numbers.