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Sat Mar 31, 2018, 12:16 PM

Upgrading Low Quality Iron Ores With Biomass Gasification/Coal Tars.

I have no use whatsoever for the ethically vacuous "free marketeer" philosophy, since it posits that some human beings have the right to destroy arbitrarily the lives of other human beings solely for their self interest.

This said, there are two kinds of appeals to "free market" nonsense, the puerile and the sophisticated.

The puerile type consists of the destructive nonsense put out by that vicious and despicable muddled self declared "thinker" Ayn Rand, who unfortunately lived at all - never mind too long - and is embraced by middle aged eternally intellectually teen aged muddle heads like, say, Paul Ryan, whose life experience should have been limited to playing video games in their parents bedrooms, but nevertheless have ended up defending overt racists in, of all places, the House of Representatives.

The sophisticated type is the one that points out that most of us - at least in the so called "First World" - are culpable in the amoral destruction of other human lives - the lives I personally rail about, spitting in the wind, are the lives of all future generations - and that we are by definition hypocrites if we object to the outcome and implication of our lifestyles with respect to other human beings, current and future.

I admire and often study the thinking of the great technological philosopher and scientist Vaclav Smil, whose rhetoric is often of the second type. Note that this is decidedly not of the discipleship type characterized by the Ayn Rand/Paul Ryan Bozo cartoon type, and their "Objectivist" pseudoathesim in which they nonetheless grovel at the foot of a clay goddess who authored holy books for the mindless. No, by contrast, when I read Smil it is often (but not always) to be challenged to find ways to argue that he might be made wrong, even if he is right now.

One of Smil's writings that has challenged me concerns iron - hence the title of this post - this one: The Iron Age & Coal-based Coke: A Neglected Case of Fossil-fuel Dependence.

I never tire of saying that I feel that it is a moral imperative to entirely end dependence on fossil fuels, since they are clearly not sustainable, and yet, as Smil points out, we live and have lived for well more than a millennium, in an age of iron, in modern times, complex steel alloys, all of which rely on the use of carbon, carbon almost always obtained from coal.

Our generation has consumed the best ores for pretty much all of the essential elements in the periodic table, and what remains for the future generations is our table scraps, our garbage and the poor pickings of future generations. This is true to some extent even for very common elements like aluminum and iron. (In the former case, cryolite mines in Greenland were completely depleted by the 1980's and all modern cryolite - the flux intermediate for the Hall electrolysis process by which all aluminum is made is now synthetic.)

It is thus with some interest that I came across this paper in the scientific journal Energy and Fuels that discusses a process for upgrading the low quality iron ore Goethite by combining tars that derive not only from coal, but from biomass gasification. The paper is this one: Integrated Pyrolysis–Tar Decomposition over Low-Grade Iron Ore for Ironmaking Applications: Effects of Coal–Biomass Fuel Blending (Akiyama et al, Energy Fuels, 2018, 32 (1), pp 396–405)

Biomass gasification is one of a few technologically feasible paths for removing the dangerous fossil fuel waste carbon dioxide from the atmosphere - but only if the heat is provided by nuclear energy, and not by combustion. However, in the case of many of these processes, most of them in fact, a side product remains, "tars" and/or "asphaltenes."

From the introductory text:

Presently, ironmaking industries face problems related to the depletion and shortage of both high-grade iron ores as raw materials as well as carbonaceous material as a primary reduction agent. The effective utilization of low-grade ores, such as goethite (FeOOH), in the modern ironmaking industry is highly attractive to solve problems related to the depletion of high-grade iron ores. Goethite, however, cannot be directly charged into a blast furnace as a result of its high combined water content.(1-6) Previous researchers proposed a new process called the integrated biomass or coal pyrolysis–tar decomposition process that solves these problems simultaneously. This process aims to reduce tar by decomposing it as deposited carbon over low-grade iron ore as well as using chemical vapor infiltration (CVI) to produce carbonized ore.(7) The report described fundamental experiments of an ironmaking process that used low-grade iron ore and woody biomass. The decomposition of biomass tar produced carbon that deposited within the iron ore pores, resulting in partial reduction of the iron. Furthermore, nanocracks suitable for carbon deposition were initiated and propagated during this dehydration. Carbon tar completely filled the nanocracks and increased the carbon content, which could be used as a potential reduction agent.(8) A similar method was applied using steelmaking slag as supplementary fuel in a sinter machine.(9) The CVI ore can then be used for ironmaking applications because it has a higher reduction reactivity as a result of the nanoscale contact between iron oxide and carbon.(10) Investigations have been performed on the carbon deposition of various solid fuels, including high-grade bituminous coal, low-grade lignite coal, and biomass palm kernel shells.(11) However, a new challenge was introduced: to produce a CVI ore with a higher carbon content as a reduction agent.

In modern blast furnace operation (typical case in Japan), 385 kg of coke per ton of hot metal is needed, while 112 kg of pulverized coal per ton of hot metal is injected.(12) For every ton of coke produced, around 1.6 tons of coking coal is used.(13) However, because high-grade coal (coking coal) tends to be expensive with limited availability, the utilization of biomass (mainly wood) as a substitution for coal (which is a non-renewable carbonaceous material) also gained much attention in an attempt to reduce greenhouse gas emissions. Furthermore, utilization of any individual biomass material normally faces several problems, such as seasonal harvesting, which limits year-round availability, higher transportation costs, and lower fuel qualification properties.(14)...

The chemistry of biomass is extremely complex, especially since practical sources of it involves hundreds if not thousands of species grown under variable conditions. Further adding to this complexity, a plethora of strategies for processing it into gaseous compounds exist. The authors offer a brief description of a current highly sophisticated effort to rationalize some of these parameters by referring to what is called the "Distribution Activation Energy Model" or DAEM, which evokes a beautiful looking equation.

The authors write:

The basic assumption of the DAEM is that many solid fuel decomposition reactions take place during pyrolysis. It can be simply approached as a sum of an unlimited number of parallel first-order decomposition reactions. When multiple Gaussian distributions of activation energy are applied, the DAEM equation can be written as

where Xcalc is the calculated residual volatile fraction of solid fuel at a given time, n is the number of activation energy distributions, β is the heating rate (K s–1), k0i is the pre-exponential factor of constituent i (s–1), σi is the activation energy variance of constituent i (kJ mol–1), E0i is the mean activation energy of constituent i (kJ mol–1), R is the gas constant (J mol–1 K–1), and T is the absolute temperature (K).

The authors walk us through a few iterations of this equation to get an even more beautiful looking equation, this one:

At this point, I plainly confess that the actual use of this equation if over my head, despite the obvious appeal to the Arrhenius law in the integral in the exponent of another integrated exponential, but that's OK, because this is the first time in my life I ever heard about DAEM related work with respect to biomass gasification. Playing with that equation has to be fun. I do hope to find the time to get to the references some day and learn about this beautiful thermodynamics.

You learn something every day...if you're lucky, and I am lucky, bourgeois piece of crap that I am.

Anyway, the authors get down to performing some experiments with biotars and coal tars.

Here's a schematic of their apparatus:

The caption:

Figure 1. Apparatus configuration for integrated pyrolysis–tar decomposition–carbon deposition over iron ore.

It looks like a mini-retort.

They study their process by the use of thermogravimetric analysis, (TGA), a TGA being a device that measures the loss of mass as a substance is heated. This is plotted along with the DTG, the "Differential Thermogravimentric" curve, which represents the rate of decomposition, in essence the derivative of the TGA output as a function of temperature.

The caption:

Figure 2. TG/DTG profiles and the highest decomposition rate temperatures for coal–biomass blending with different BBRs during pyrolysis. Coal and biomass particle size = 125–355 μm.

Here "BBR" refers to the biomass blending ratios, the ratio of biomass to coal.

It is useful to stop here to speak about the coal component of this system, since many of my writings on the internet are adamant that coal mining and use should be phased out rapidly. With due deference to the exceptional mind of Vaclav Smil, I do believe that synthetic coal that will be superior to mined coal is in the realm of possibility and further, with input of energy, and I also believe it is technically feasible to make synthetic coal from, um, carbon dioxide. The path for doing this would involve (besides procuring the carbon dioxide) a metal based carbon dioxide splitting thermochemical system driven by nuclear heat or by reformation of either waste plastic or biomass with carbon dioxide as an oxidant. The resultant carbon monoxide could then be disproportionated into pure carbon and carbon dioxide using a chemical equilibrium - also a function of temperature - known as the Boudouard equilibrium, CO2 <-> CO + C.

All that is required is energy, which at least in theory is available in unlimited supply since uranium is available in unlimited supply, since there is so much uranium on this planet that humanity could never consume all of it without vaporizing the planet, something that is obviously to be avoided, even if it is possible.

With appropriately Rube Goldbergish heat flows, this need not be all that expensive for future generations, who couldn't possibly be more stupid than our generation, a generation that has allowed an orange baboon with a poor intellect and a non-existent ethical matrix that is Ayn Randian in dimension into the White House.

In any case, coal that finds its way into steel making is at least partially sequestered more or less permanently, at least in high carbon steels.

On this score, it is popular on the American left - and I say this criticizing my own demographic - to pretend that "coal is dead," because the orange baboon has represented that he was going to restore allegedly "dead" coal in the United States. The American left also likes to pretend that the "fastest growing source of energy" on this planet is so called "renewable energy," one component of which, wind energy, is highly reliant on access to steel.

Neither of these pretensions are even remotely true, as I repeatedly point out by reference to the International Energy Agency's World Energy Outlook 2017 report:

IEA 2017 World Energy Outlook, Table 2.2 page 79

Converted MTOE in the original cited table table in the report to the SI unit exajoules in this text one can learn that allegedly "dead" coal has been for the entire 21st century the fastest growing source of energy on this planet, having increased by 60.1 exajoules in the period between 2000 and 2016, 2016 being the last year for which data has been fully compiled. Overall the consumption of coal has risen to 157.2 exajoules out of 576 exajoules the report says was being consumed as of 2016. This makes coal only second to dangerous petroleum as a source of energy on the planet, which grew by "only" 30.1 exajoules to a total of 183.7 exajoules.

The entire so called "renewable energy" scheme, after sucking trillions of dollars out of the world economy does not produce even 10 exajoules of energy, 9.4 to be more precise, having grown by only 6.9 exajoules in the 21st century, or a little more than 11% as fast as coal, never mind dangerous petroleum and dangerous natural gas.

Anyway, back to steel making with biomass cut with a little dangerous coal:

The authors work to explore the parameters in the DAEM equations evoked above and, then, continuing to look at the pictures as a way of understanding this work they produce the following bar graph:

The caption:

Figure 4. Carbon yield product distribution of integrated pyrolysis–tar decomposition in a N2 atmosphere at a pyrolysis temperature of 1073 K and a tar decomposition temperature of 873 K for 40 min. Case A, co-pyrolysis only; case B, co-pyrolysis with tar decomposition over porous iron ore (3 g).

Here's a blurb from the text discussing the bar graph:

The integrated coal–biomass co-pyrolysis–tar decomposition over low-grade iron ore was designed to reduce the tar product while simultaneously converting it to carbon deposited into the iron ore. Moreover, production of high carbon content carbonized ore is desired. Figure 4 shows the product distribution carbon yields from integrated coal–biomass pyrolysis, for both pyrolysis only (case A) and pyrolysis–tar decomposition over porous iron ore (3 g) (case B). The observed pyrolysis products were the carbon yield of char, heavy tar, light tar, deposited carbon in iron ore (case B only), and gas at any BBR. Heavy tar and light tar in this experiment were separated by the boiling point according to the International Energy Agency (IEA) tar protocol, in which the components with the boiling point higher than 378 K could be categorized as the heavy tar fraction.(35) The deposited carbon in iron ore is the carbon amount of solid fuel that deposited in the iron ore bed during the CVI process, which was evaluated from mass balance. In contrast, the carbon content in iron ore was measured by the CHN/O/S elemental analyzer. The term of the deposited carbon and the carbon content in CVI ore were introduced to distinguish the different points of view. It was obvious that the total carbon yield of the biomass pyrolysis product is lower than the coal product because biomass has a lower carbon content than coal. Total carbon yields of the coal–biomass blends gradually decreased at elevated BBRs.

Note that the main product here in terms of mass is gas. It is important to consider what these gases are, since coal is involved and the potential for dumping gases into the planetary atmosphere as fossil fuel waste is not acceptable, even if almost universally practiced.

Another figure from the text, showing gas compositions:

The caption:

Figure 7. Effect of co-pyrolysis at different BBRs on gas H2, CH4, CO, and CO2 product distribution of integrated pyrolysis–tar decomposition in a N2 atmosphere for 40 min at a pyrolysis temperature of 1073 K and tar decomposition temperature of 873 K. Case A, co-pyrolysis; case B, co-pyrolysis with tar decomposition over porous iron ore (3 g).

The point here was to convert a low grade iron ore, goethite, the table scraps we leave for future generations as an expression of our generalized contempt for our children and their decedents - our contempt for humanity as a whole - into an ore of a quality that we enjoyed but squandered on quixotic enterprises like cars and idiotic wind turbines, magnetite. This has been achieved by this process.

By reference to the immediate figure above, a note is in order about the composition of the gas component.

Here is the chemical equation for the pyrolysis reactions:

The authors write:

The significant increase of H2 and CO2 at higher BBRs could be correlated to the presence of water from biomass pyrolytic tar-promoting steam reforming, as in eq 8, and water-gas shift reaction (WGSR), as in eq 9.

The "water gas shift reactions" are these:

The gases above, as mixtures of carbon oxides and hydrogen are forms of what are known as "synthesis gas" or "syn gas" for short, from which pretty much any modern commodity carbon compound may be formed. (Such practices may require hydrogen from thermochemical or biomass reforming based water or carbon dioxide splitting.) To the extent that such practices result in polymers, or engineered carbon products such as carbon fibers, graphene or carbon based ceramics such as metal carbides and MAX phases, they represent economically valuable carbon sequestration.

They need not be dumped in the atmosphere as waste, despite our current practice.

A better world is possible, even if it is less and less likely.

Enjoy the weekend, and if you come from a Christian cultural background, have a happy Easter.

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Reply Upgrading Low Quality Iron Ores With Biomass Gasification/Coal Tars. (Original post)
NNadir Mar 2018 OP
hunter Apr 2018 #1
byronius Apr 2018 #2
NNadir Apr 2018 #3

Response to NNadir (Original post)

Mon Apr 2, 2018, 01:43 PM

1. I'm wary of *ANY* biomass schemes...

... in a world that worships the false god of economic "productivity" and consumerism.

I can't help but recall the various palm oil biodiesel schemes. Those were something worse than stupid fossil fuel burning diesel automobiles with fraudulent emission control systems, or future solar and wind energy electronic waste. Fuck you and your mother, baby orangutan, my biodiesel car is "green." Monoculture vegetable oil or ethanol ain't much better, there's no buffalo and wolves and aboriginal Americans wandering those bleak plains.

If the cheapest steel was made directly from the corpses of endangered species and welfare recipients there would be some worshiper of the Ayn Randian magic-hand-of-the-free-market willing to trade in it.

I'm of a Christian cultural background and had a very fine Easter with family and community, thank you. Very well sprinkled with water. Nope, didn't melt like the Wicked Witch, so there's still some hope for my twisted immortal soul...

I suppose it is comforting that our descendants, should they choose a far more rational path than we have, will be able to make the steel required to raise the living standards of every human being with minimal environmental impacts.

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Response to hunter (Reply #1)

Tue Apr 3, 2018, 04:10 PM

2. Too bad most of these lessons are kinda fatal.

Any consumer of science fiction longs to leap over all this crap. The religion of consumerism and the domination of nature are basic assumptions in almost any economic scheme, much like they are for colonies of bacteria that multiply until the food and air are gone.

Later, they'll be soil.

I hope I grow a nice tree.

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Response to hunter (Reply #1)

Tue Apr 3, 2018, 10:53 PM

3. I hear what you're saying and in fact, I've written many times about the palm oil thing...

...most often when describing the 1998 CO2 surge from the Malaysian/Indonesian palm oil plantation fires, but the work described here is not quite the same as biomass crops grown to fuel so called "renewable stuff."

One can eloquently debate the demerits of consumerism and be right on the mark, but the question that I am asking myself is not really about prevention. We have already failed to prevent a disaster; the disaster is on going.

The question I am asking is concerns whether it is possible to clean up this mess; whether or not some portion of what was or what remains can be restored. The entire planet is now a superfund site.

The technology here is gasification, and gasification works with any carbon source, including "waste" biomass. This includes things like straw, food waste, waste wood, grass clippings, and in fact, water contaminated with heavy amounts of biomass, such as that in destroyed ecosystems like the Mississippi delta, and portions of the Great Lakes and even open oceans.

Whenever we engage in the thermal decomposition of biomass (of any source) we will generate some fraction of tars and/or asphaltenes. We may adjust the amounts somewhat by careful manipulation of process conditions, but we will always get some.

From my perspective there are only two possible pathways for the removal of carbon dioxide from the atmosphere; one is biomass, the other is processing seawater. Both have environmental drawbacks, but I regard them as being possible to address.

In the biomass case, the big issues are both tar and phosphorous flows (and other mineral flows).

This is no panacea. On another website where I was banned for telling the truth, I once calculated that the carbon content of "all the straw in China" assuming it could be perfectly recovered - which it can't be - is relatively modest, on the order of a quarter billion tons.

All the Straw In China, a B.O.E. Calculation for Carbon Capture Potential.

We are now dumping about 35 billion tons of carbon dioxide into the planetary atmosphere each year, corresponding to roughly 10 billion tons of carbon.

The scales are astounding.

So biomass will never be anything but a baby step unless all carbon dioxide dumping is stopped; something for which there is no moral or political will to do.

Nevertheless, this paper, which is laboratory scale only and is thus probably meaningless, suggests some modest pathways to treat low grade iron ores and to break down biomass tars. It's "waste to materials" and this is what I think that future generations will need to explore in order to clean up the awful mess we've made for them with our irresponsibility and our lotus eating faith in so called "renewable energy."

Thanks for your comment.

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