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:
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:
(1)
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:
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:
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:
Here's a blurb from the text discussing the bar graph:
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:
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 "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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