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Sun Oct 20, 2019, 09:24 AM

An Economic, Environmental, and Technical Analysis of Biomass Sourced Jet Fuel.

The paper I'll discuss in this post is this one: Comprehensive Life Cycle Evaluation of Jet Fuel from Biomass Gasification and Fischer–Tropsch Synthesis Based on Environmental and Economic Performances (Xiao et al, Ind. Eng. Chem. Res. 2019, 58, 19179−19188)

I have very little use for Bill McKibben of 350.org because although he "cares" loudly about climate change, he is nothing more than a journalist, and a cowardly one at that, since it is increasingly obvious that his prescribed solution, so called "renewable energy" has clearly not worked, and is not working and won't work. McKibben is a journalist. I often joke that one can only get a degree in journalism these days if one has not passed a college level science course.

No one now living will ever see an atmospheric concentration of the dangerous fossil fuel waste carbon dioxide measuring under 400 ppm again, never mind "350." Next year I'm certain I'll be able to say - if still alive - "under 410 ppm again." The blind, and frankly ignorant faith is so called "renewable energy" is one reason why this is so. The more than 2 trillion dollars spent in the last ten years alone on this scheme has caused climate change to accelerate, not decline. We are now seeing increases at 2.4 ppm/year, an unprecedented rate.

I call McKibben a "coward" because it takes courage to say "I am wrong" or "I was wrong" and he clearly lacks this ability, since the only way to be serious about climate change is to embrace science and engineering, as opposed to driving one's Prius (or Tesla electric) car to protests chanting "We want 'renewable energy now!' and carrying signs that the bearers consider witty. Over the last several hours I've been studying lignins, a component of wood and the stalks of many plants, and as a result have been studying the environmentally dubious Kraft process for wood pulping, which is utilized to make paper for signs people can carry to their protests stating how much they care about the climate.

Bill McKibben lacks both the courage and the intellectual insight and education to be able to say the word "nuclear."

If one respects science, one considers how scientists work. We have theories or hypotheses which must be tested by experiment. If the experimental results invalidate the theory, the theory goes, not the experimental result. We don't make Trumpian scale excuses for the experimental result in order to save a precious theory, which by being precious translates into blind faith. The experimental results of the multitrillion dollar "renewable energy will save us" theory are in; climate change is accelerating, not being ameliorated. It's time for the theory to be rejected. Denial and excuses for the experimental result are meaningless. No one now living will ever see an atmospheric concentration of the dangerous fossil fuel waste carbon dioxide measuring under 400 ppm again. The so called "renewable energy" experiment did not work; it is not working; it won't work.

The purpose of this riff on McKibben, who I obviously hold in low regard, is a bit of "Gotcha," which has come to permeate our culture of anti-thinking, the age of twits posting twitter witticisms, all of which are making the world worse, not better.

To avoid "Gotcha" statements the young climate activist Greta Thunberg took a sailboat across the ocean to address the UN on climate change. She declined to fly, since flying requires the consumption of rather large amounts of fuels based on dangerous petroleum. This reminds me of a statement I heard attributed to Mahatma Gandhi in which he remarked that his advisers complained that was very expensive to be sure he was keeping his vow of poverty in place.

By the way, I have enormous respect for Greta Thunberg, because I think she is right to ask us "How DARE you?!!!" about what we in my generation have done to hers.

History will not forgive us; nor should it.

It's OK for Greta Thunberg to not know anything about engineering by the way; she's sixteen. (Bill McKibben is 58.)

Now.

In general, as I've just made clear, I am hostile to so called "renewable energy" not because its slightly better than dangerous petroleum, dangerous coal and dangerous natural gas, when it functions, but because it requires dangerous petroleum, dangerous coal and dangerous natural gas to back it up when it's not working, which is often. This is why it is not working and won't work, and why Germany and Denmark have the highest electricity prices in the OCED, because a system that requires redundancy is obviously more expensive than one that doesn't, and not only that it, it is worse from an environmental standpoint. (We hit 415 ppm of CO2 this year.)

Still, despite to my hostility to so called "renewable energy" I am flexible enough to be intrigued by what is, by far, the largest source of it, biomass. As practiced now, biomass is a health and environmental disaster: Slightly less than half of the world's 7 million air pollution deaths each year derive from it, and the Mississippi River Delta system, along with other bodies of water, has be destroyed by agricultural fertilizer run off to make corn ethanol, and the Indonesian and Malaysian rain forests are being rototilled to make biodiesel to meet German "renewable portfolio standards."

Nevertheless, biomass relatively efficiently captures carbon dioxide from the air, and this is a non-trivial task that we leave for Greta Thunberg's generation to accomplish with depleted resources and a degraded planet. Biomass, especially algae biomass, is fast growing, self replicating, and capable of covering the large surface area required to address the entropy of mixing that makes cleaning up the dangerous fossil fuel waste carbon dioxide. Thus it cannot be ignored.

This brings me to the paper at the outset. This is one way to make jet fuel so Greta Thurnberg can feel safe to fly someday, but there are others, one of my personal favorites being that proposed by the US Naval Scientist Heather Willauer , although in truth, it's less than perfectly idea since it requires an electricity intermediate and is thus thermodynamically questionable.

The best way to deal with biomass in my opinion is heat driven gasification, which what the paper cited at the opening of this post is about.

The cartoon graphic introducing the paper:




From the introduction:

With increased aviation travel and limited substitutes in this area, jet fuel demand has increased significantly. The traditional jet fuel consumes huge fossil energy and leads to serious environmental pollution. With the global warming effect, biomass, as a renewable resource to produce jet fuel, has attracted progressively more attention at the global scale. In recent years, the conversion routes of jet fuel derived from biomass mainly include catalytic cracking-olefin oligomerization, hydroprocessed esters, and fatty acids, Fischer–Tropsch (FT) synthesis, hydrothermal liquefaction, and fermentation alcohol synthesis.(1−10) However, the environment, resource, and economic performances of biomass-based jet fuel need to be evaluated and compared for seeking beneficial technical pathways.

The life cycle assessment (LCA) is a method for evaluating the environmental impact of a product throughout its life cycle. In order to compare the influence of different processes of biomass-based jet fuel on the environment and resources, some literature studies carried out a variety of life cycle evaluations of the abovementioned conversion processes. These studies mainly focused on the contribution of biomass-based liquid fuel to mitigate the greenhouse effect. Moreover, some comprehensive evaluations were based on the fuzzy mathematics method, such as the analytic hierarchy process (AHP).
Several researchers(7−9) performed the LCA of biomass-based jet fuel derived from hydrothermal liquefaction (HTL) of microalgae. Two HTL processes of algal jet fuel based on the different circumstances were analyzed, and Monte Carlo simulation and sensitivity analysis were completed. The results showed that the transportation of microalgae led to the increase in the life cycle climate change impacts, and compared to the process of petroleum-based jet fuel, greenhouse gas emissions could be reduced by 76.0% based on the optimized process of algal jet fuel.

Klein et al.(3,4) compared different routes for renewable jet fuel (RJF) production integrated with sugarcane biorefineries in Brazil based on the technoeconomic and environmental assessments. They concluded that hydroprocessed esters and fatty acids exhibited the highest production potential and FT synthesis showed the best economic performance among the studied scenarios of RJF. Moreover, all conversion technologies of RJF could reduce greenhouse gas emissions by more than 70% compared to the process of petroleum-based jet fuel...(10)

...Moreover, many researchers have integrated the AHP into LCA to evaluate the comprehensive performance of products.(14−16) Tao et al.(6) obtained a resource-environment-economic comprehensive performance evaluation model of biomass-based jet fuel from biomass gasification and FT synthesis based on AHP. They showed that the case of biomass-based jet fuel combined with waste heat for power generation exhibited a lower environmental impact than that combined with heat supply directly and the reduction of environmental impact indicators was in the range of 11.7–40.8%. Compared to petroleum-based jet fuel, the global warming potential (GWP) of biomass-based jet fuel reduced by 52.6–71.9% and the nonrenewable resource consumption reduced by 84.4–93.6%. Different environmental impact distribution methods, such as based on economic value distribution, energy distribution, and mass distribution, used in the biomass growth stage led to significant changes in the environmental evaluation, in particular, for GWP and eutrophication potential (EP). It could also be found that the comprehensive performance of biomass-based jet fuel is the most sensitive to feedstock consumption...

...The method of monetization is more objective and rational, which has the same criteria for weighting economic performance, resource performance, and environmental performance. Therefore, the comprehensive evaluation obtained is fairer to the entire society, and its decision-making meaning is more perfect. This study not only employed the monetization method to reflect economic benefits but also completed the comprehensive analysis through the monetization method on resource and environment, to avoid the subjective factors in comprehensive evaluation.


Some graphics from the text beginning with a process flow sheet diagram:




Figure 1. Process of jet fuel from biomass gasification and Fischer–Tropsch synthesis


It is important to note that this analysis relies of combustion heat, and not nuclear heat, and therefore can be improved upon. Specifically in this diagram the heat is generated by the combustion of biomass, reducing the amount that can be recovered as a biofuel. However I very much like the FT approach and the heat exchange networks.

Two cases are considered:
Considering petroleum-based jet fuel as a reference, the performances of economy, resource, and environment were reflected by relative economic benefits (REBs), nonrenewable resources saving benefits (NRSBs), and pollution mitigation benefits (PMBs). These indicators are defined in the subsequent sections. Each alkane mixture is separated by distillation, and then the final product jet fuel (C8−C16), gasoline (C5−C7), and diesel (C17−C20) are obtained, in addition to by-product wax. The steam generated by the waste Figure 1. Process of jet fuel from biomass gasification and Fischer−Tropsch synthesis. heat is supplied for two cases, that is, heat directly (Bio-FTJ-1) and power generation (Bio-FTJ-2) cases.


Here is the grounds for the LCA analysis, note the presence of fertilizers and pesticides. These may not be necessary if the water utilized to grow the biomass is municipal waste water, or agricultural run-off water, since these are potential media for algae growth. The big problem with Algae growth is dewatering and transfer, both of which can be addressed to improve the process, dewatering by the use of waste heat, transport by direct flow into reactors. (This would also have the added advantage of recovering phosphorous, the depletion of which is another very, very, very, very serious matter we are dumping, with contempt, on Greta Thunberg's generation. How DARE we?)



Figure 2. Scope of LCA of Bio-FTJ systems.


An issue often ignored is the material costs of so called "renewable energy," which calls into question how "renewable" it is - this is a serious paper, not hand waving - is not not ignored here:

Table 2: from the paper:



Costs of this process, again analyzed in the absence of nuclear heat:



It is important to note that in the case of dangerous petroleum fuels, the economic costs of the destruction it causes, the costs of deaths and cost of disease from air pollution, and the cost of climate change - i.e. "external costs" - are not included. If they were, petroleum would be too expensive to use, inspiring idiots like Jim Kunstler to carry on how about we'll all die without oil, that "peak oil" nonsense. These external costs are not included although, they should be in an LCA paper in the analysis of the cost of petroleum jet fuel in table 4. I do not mean to criticize the authors or their fine work here, but they are buying into the fact that we blindly accept these enormous dangerous fossil fuel costs by habit while we all wait breathlessly for the grand renewable nirvana that never comes, and not because it is morally or intellectually justifiable.

Table 4:



For the next few graphics, there is a parameter called "ICP" for Indicator of Comprehensive Performance. There are also parameters associated with the weighting of these indicators, described in the text as follows:

Considering petroleum-based jet fuel as a reference, the performances of economy, resource, and environment were reflected by relative economic benefits (REBs), nonrenewable resources saving benefits (NRSBs), and pollution mitigation benefits (PMBs). These indicators are defined in the subsequent sections.


The weighting factors utilized in the analysis of these are assigned in the graphic below, where the weighting factors are described thusly:

α, β, and γ represent the weighting coefficients of REB, NRSB, and PMB, respectively.




Figure 3. ICP with different weighting coefficients.



The next graphic on the sensitivity of benefits to the price of oil depends on the dubious assumption with which we all live that dangerous fossil fuels are allowed to dump the dangerous fossil fuel waste without charge.



Figure 4. Sensitivity of ICP to different prices.


A genuflection to this fact that dangerous fossil fuel wastes can be dumped without charges accruing to users and dangerous fossil fuel companies.



Figure 5. Sensitivity of ICP to resource consumption and pollutant emission.



Figure 6. Influence of into-factory price of stalks on performance.


The next graphic refers to the price of stalks delivered to the plant; this is not an algae based process.



Figure 7. Influence of stalk consumption on performance.


And the final figure refers to the influence of the cost of oil, which is subsidized by lung tissue, the destruction of habitats, and the destruction of the future of Greta Thunberg's generation and all generations after hers.




Figure 8. Influence of the price of crude oil on REB.


Some conclusions to the paper:

Compared to Bio-FTJ-1, Bio-FTJ-2 can achieve greater benefits in saving nonrenewable resource and can emit less CO2 and other pollutants because it significantly reduces the consumption of external power input. However, owing to the high production cost of Bio-FTJ-2, its economic benefit is very low. Therefore, ICP of Bio-FTJ-2 is lower than that of Bio- FTJ-1.

According to the sensitivity analysis, the comprehensive performance of the two processes is highly sensitive to the price of crude oil and stalk consumption and the Bio-FTJ-1 is highly sensitive to electricity consumption. The higher the price of crude oil is, the better the comprehensive performance of the Bio-FTJ is. The results of this study indicate that the comprehensive performance of Bio-FTJ can be improved significantly by the reduction of the consumption of stalks and external power input in the production.


I trust you're having a nice day.

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Reply An Economic, Environmental, and Technical Analysis of Biomass Sourced Jet Fuel. (Original post)
NNadir Oct 20 OP
John ONeill Oct 22 #1
NNadir Oct 22 #2
John ONeill Oct 23 #3
NNadir Oct 23 #4

Response to NNadir (Original post)

Tue Oct 22, 2019, 01:51 AM

1. Aircraft warming effects

The trouble with allegedly carbon neutral jet fuel is that the warming effect of aircraft is between three and four times more than that of the CO2 emissions alone. Each ton of avgas burnt produces three tons of carbon dioxide, but also over a ton of water vapour, plus nitrogen oxides and carbon particles. The water vapour would be of little consequence at lower altitudes - humidity is much more affected by run of the mill weather - but at 35,000 feet, above the tropopause, the air is normally dry. Large tropical storms can sometimes punch moisture up into the lower stratosphere, but aircraft do it all the time. This effect would be even worse with planes powered on pure hydrogen ( and the ballyhooed 'hydrogen economy' would probably leak enough hydrogen upwards to have a similar effect, once the H2 oxidised at height.)
The effects of exhaust on the ozone layer, and on cloud formation, are more complicated - there can be cooling, from vapour trail albedo, as well as heat retention.
Most jet fuel is now sulfur-free. There has been talk of using sulfur aerosols to mimic volcanic cooling, in a bid to slow down warming while we battle with reducing CO2 emissions, but they would have to be put at higher altitudes - sixty to ninety thousand feet - so just re-polluting our current air fleet's fuel would not work. According to this article, aerosol particles from aircraft already kill many more people than plane crashes, and most of them in countries where few fly.
https://www.nationalgeographic.com/news/2010/10/101005-planes-pollution-deaths-science-environment/
Sulfur from coal burning is believed to be having a similar cooling effect to volcanic ash, to the extent that its negative forcing is on the order of one third of the positive forcing from our added CO2. This raises the possibility that cleaning up emissions from Asian smokestacks, and replacing US and European coal with fracked, methane-leaking gas and a few windmills, could take the handbrake off warming before any slowdown in CO2 output took effect.
David Keith proposes experimenting with manufactured reflective aerosols with fewer health and climate side-effects than sulfur. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2944714/
Living in New Zealand, I'm a bit down that I can't go anywhere else without effectively doubling my carbon footprint. My niece got married in Wales last month, and my siblings, with their families, attended from New Zealand, Australia, and France. I sent her best wishes and my air fare instead - I figure that will do them more good than my presence would have. Nuclear powered ships or surface-effect craft could maybe replace aircraft in Greta's lifetime, but not in mine.

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Response to John ONeill (Reply #1)

Tue Oct 22, 2019, 05:59 PM

2. Well, I definitely oppose the sulfuric acid idea; it's one of the worst ideas in geoengineering.

I'm a bit closed minded on this subject. The only geoengineering I can accept - although I fully concede it is technically challenging - is the removal of carbon dioxide from the atmosphere and its reconversion to the solid state.

As for jet fuels: It does seem to me that the issue with carbon particles can be engineered away from fuels, particularly if one is making them on a FT (or alternate) basis. Nitrogen oxides are not so clear, but the ready availability of so called "precious metal" catalysts from used nuclear fuel might make catalytic decomposition readily capable of solving the problem.

As for water in the upper stratosphere:

A certain amount of particulates might be desirable however as ice nucleation agents. I would have assumed that cirrus clouds significantly raise the albedo of the earth, deflecting radiation, but a very quick superficial look suggests that they in fact work to trap IR radiation, which I didn't know until just now, and are more efficient at doing so than at reflecting sunlight.

I should have known this; water is a greenhouse gas, albeit an essential one, as is small amounts of carbon dioxide.

On the other hand, if I recall correctly, ice crystals can act as catalytic surfaces in the decomposition of CFCs, which have not gone away, in an ionizing radiation field. To the extent this is true of other highly problematic gases, for example sulfur hexafluoride and its degradants, I cannot say with authority, although I've probably looked up sometime in the past. I can't remember for this specific compound, but I can look through my files.

It's not a point I've considered before, the effect of upper atmospheric water, so thank you for stimulating some thought on the subject on my part.

I did just download a monograph for further reading, should I find time - harder and harder to do - this one: Fundamentals of Physics and Chemistry of the Atmosphere. I had a nice monograph on atmospheric chemistry back in the 1980's; it seems to have disappeared; I was looking for it a few years ago. Some people think of my home as a "borrowing library," which makes my wife happy, since she thinks there are too many books in the house, a point I have to take given that an electronic library is easier and cheaper to store.

Anyway.

I'm not as hostile to air travel as I am to automotive travel, because I do think that the more humans can interact, the less violent and stupid they will be. The fuel efficiency of a flight can be considerably lower than a car per km, but not as clean as a nuclear powered ship to be sure. It is probably the case that air travel cannot be made environmentally benign, but on the other hand, neither can the existence of human beings, but I nonetheless confess to some humanist sympathies.

I can't say that I actually favor nuclear aircraft, although the record of RTGs crashing into Earth has been something of a non-issue which is not to say that people like say, Michio Kaku are prevented from getting excessively stupid about such things, as happened in the Cassini debacle.

Nevertheless I've watched too many episodes of the wonderful engineering TV show "Air Disasters" to think a reactor in an atmospheric aircraft is necessarily a good idea. Of course, in the 1950's, the idea of building one lead to some fabulous outcomes in nuclear engineering, especially those loved by the thorium people today.

The point is that synthetic fuels certainly offer opportunities that fuels obtained from dangerous fossil fuels do not offer. We can design them to burn much cleaner, although their exhaust will always include both carbon dioxide and water. To the extent we can close the carbon dioxide cycle, we can make this sustainable. That is, to the extent that these fuels are made from carbon dioxide, rather than fossil carbon, they can be far less noxious.

The more carbon dioxide is utilized, the more it is a valuable commodity rather than a waste, the better we'll be. (Dumping it won't work.)

I read an awful opinion piece, in Nature no less, by the asshole who used to head up Greenpeace, on why he welcomed climate catastrophe, since he, in a somewhat Trumpian vision of himself as an exalted sage, assumed that everyone would take a vow of poverty along the lines he stupidly proposed as the only viable means to address climate change some years back. The "ideas," such as they were, were so absurd as to assure that things would get worse, not better, since no one could possibly take such asinine stuff seriously.

"'Make the planet great again,'" I guess, "only Paul Gilding, despite lacking even a shred of understanding of engineering, can do it."

Nature: Paul Gilding; Why I Welcome a Climate Emergency. Hint: It involves his Greenpeacy "One Degree War Plan."

He welcomes climate change...

This is like welcoming lung cancer as a wonderful opportunity to try out shamanist cures.

You hear these sort of things, and you really can't believe it. Gilding, to my mind, is a cause of climate change, specifically his application of his poor education, bad thinking, and pure ignorance.

Anyway, despite my angry riff, thanks for your thought stimulating comment. It's much appreciated.

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Response to NNadir (Reply #2)

Wed Oct 23, 2019, 01:30 AM

3. Nuclear flight

..is possible, I think. Standard jet takes off from NY, flies to ~20,000 feet and the three mile limit offshore, then unreels a drone from front undercarriage bay. Drone automatically hooks up with another, towed 2,000 feet behind a robot nuclear tug. Tug is unshielded, except for directly behind the reactor. Jet turns off all engines except the auxilliary power turbine and is towed across the Atlantic. There the jet resumes independent flight and the tug picks up another for the return trip. Any line breaks, they just resume normal flight. By keeping station above the tug turbulence, they'd be clear of any line whiplash, and in the radiation shadow of the tug's shielding plus half a mile of (thin) air.
I've done twenty or thirty glider flights under tow, and once airborne, it's pretty stress free. A largely unshielded reactor would still transmute some nitrogen to C14, but probably not too much if the air didn't flow directly through the core.
Technically plausible, but politically a non starter.

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Response to John ONeill (Reply #3)

Wed Oct 23, 2019, 05:30 PM

4. Well, it's certainly not any more wild than some ideas I've had over the years. I find...

...that it's worth thinking a little outside the box.

My personal craziest idea was a liquid radiocesium cooled reactor with a magnetohydrodynamic direct generator. I envisioned it as a tool that would use the maxwell-boltzmann distribution to separate cesium isotopes.

Trust me, it was nuts.

However, it certainly led me to far better ideas, especially the analysis of why it wouldn't work. Figuring out why things won't work is every bit as important as thinking of things that didn't work.

People much, much, much, much smarter than I am did extensive research on nuclear powered aircraft, so the idea is certainly feasible. The outgrowth of that work was of course the concept of molten salt reactors, which is experiencing a huge surge in popularity in modern times.

By thinking about cesium working fluids in magnetohydrodynamic reactors I caused myself to dig into several important topics about which I originally knew nothing, for example, the properties of gaseous metals, plasmas, and materials science issues that I'd never even dreamed were there.

I am a fan of actinide nitrides, for the record, more so because of things I'm of which I'm gaining knowledge via osmosis from my son. In general I do not believe in the desirability of isotope separations, and nitride fuels are less attractive if one has to separate 15N to avoid 14N. The consequence of course, of using nitrogen with its natural isotopic vector, is the accumulation of 14C.

I note that 14C has a very, very, very low neutron capture cross section, is a sort of "intermediate" moderator for producing epithermal neutrons, and that actinide carbides are fairly extreme refractories as are other carbides, for example zirconium carbide and titanium carbide.

This suggests that 14C materials have utility far beyond their current utilization as tracers in metabolomics. Slowly, perhaps over centuries, they would ultimately produce 15N enriched nitrogen.

I'm not sure that an unshielded aircraft reactor would generate all that much of that stuff - it is difficult to imagine all that high a neutron flux in a compact reactor, but were it a concern, boron is a light material and, in fact, boron nitrides are extreme refractories with interesting morphological aspects, and a side product of boron as a neutron absorbent is helium and lithium-7 for the benefit of all those electric car nuts out there. Neutron shielding is straight forward. Were I flying an unshielded (except for neutrons) nuclear aircraft, I'd take some solace in the fact that the leaked gamma radiation would have the interesting property of destroying some very recalcitrant atmospheric pollutants, specifically the halide gases.

I think this is the most overlooked value of radioactive materials, the utility they have for breaking otherwise difficult to break bonds. The accumulation of air pollutants other than carbon and nitrogen oxides is a serious matter in atmospheric chemistry, in particular with respect to climate change. It breaks my heart that valuable isotopes are allowed to decay under helium rather than exposed to the atmosphere or to contaminated water.

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