Clean fuel from dirty coal?
Posted by Heading Out on February 27, 2006 - 1:53am
Topic: Supply/Production
Tags: coal, coke, fischer-tropsch, montana, tech talk, town gas, wyoming [list all tags]
This is another in the short technical posts that show up at weekends, dealing with one aspect or another of fossil fuel production. Given that, as Super G noted the Governor of Montana was on 60 minutes tonight, it seemed like a good time to return to a coal-related theme. A list of related posts will be appended at the end of this one, and relate to the mining of coal, either on the surface or from underground, though it is the surface mining of coal, that currently entices the Montana Governor. It should be noted that the adjacent state of Wyoming produces around 400 million short tons a year of coal, about ten times the current production from Montana.
The problems of using coal, particularly unwashed coal, with the pollution it caused have been recognized for decades. Back in the 1960's much of Europe still burned coal in stoves and open fires for heating and cooking, and the resulting fumes and soot meant that buildings were blackened, and, on foggy days a combination of smoke and fog generated smog which reduced visibility to the point that you could not see your hand in front of your face (personal experience), and which had serious health consequences to those caught in one. During the London Smog of 1952 it was estimated that 12,000 people prematurely died. These smogs led to Clean Air Acts, which led to the development and use of smokeless fuels, coal that had been cleaned so that soot was not produced, and the encouragement of gas fires.
At that time in Europe the North Sea Oil and Gas fields were not developed, and so the gas was, particularly in the UK, generated from coal. It was known as town gas and often produced concurrently with coke (which is a smokeless fuel). Coke is made by heating coal, that has been washed and crushed, in larger vertical retorts, but with no air present. This drives off the gases and any volatile matter in the coal (such as hydrocarbons, tars, gasses etc).
The basic process of coke production is also that used for manufacture of town gas. Bituminous coal of the gasmaking type is perhaps 86% carbon, 5.5% hydrogen, 6% oxygen, and 2.5% or so nitrogen and sulfur. An elemental analysis is all that can be meaningfully given, since coal is a complex substance. When heated in the absence of air, coal produces carbon (coke) and a mixture of many gases, (crude coal gas). The heat for the carbonization of coal is provided by use of some of the the coke product in the strongly exothermic producer gas reaction:Until the 1950's up to 80% (pdf file) of British homes were connected to the town gas grid. Electricity replaced some of that energy, but it was the advent of North Sea gas that led to the change to natural gas, a change completed in 1974. (It required different burners on stoves and other changes that I was not there to see). Gasification from coal, however, had been the major source of gas in the UK from 1920.C + O2 --> CO2, DH0 = -393.509 kJ/mole
which in the presence of insufficient oxygen drives the endothermic formation of carbon monoxide:
CO2 + C --> 2CO, DH0 = +172.459 kJ/mole
Partial use of the endothermic water gas shift reaction equilibrium:
C + H2O(g) <--> CO + H2, DH0 = +131.293 kJ/mole
permits control of the temperature of the reaction zone and raises the heating value of the output producer gas slightly. The final composition of producer gas is about 12% hydrogen, 25% carbon monoxide, 7% carbon dioxide, and 56% nitrogen; the nitrogen comes from the air used in the producer gas reaction.
Producer gas is mixed with crude coal gas to give crude town gas. Impurities are condensed out as the gas cools (water, tar, napthalene, ammonium chloride) or by absorption in water (NH3, H2S, CO2). The rest of the H2S is removed by reaction with Fe2O3, and the purified town gas is ready for delivery. A typical composition of town gas would be about 51% hydrogen, 15% carbon monoxide, 21% methane, 10% carbon dioxide and nitrogen, and about 3% other alkanes.
The Fischer-Tropsch process is developed from these gases. As the Bureau of Mines reported
The catalyst employed in the pilot plant was nickel-manganese-aluminum oxide supported on kieselguhr and prepared by precipitating from the nitrates with potassium carbonate. Synthesis gas was prepared by conversion of coke-oven gas with steam over coke and freed from organic sulfur by heating to 400 degC in the presence of an iron catalyst and subsequent scrubbing with alkaline ferrocyanide solution. Operating conditions were specified as 1 atmosphere pressure and a temperature of 190 to 210 deg C. The catalyst was re-activated every 1,000 hours by extraction of the solid paraffin with gasoline. The catalyst chambers, suspended in an oil bath for temperature control, were narrow boxes 1.2 by 10 by 500 cm. The gasoline product of the synthesis consisted mainly of straight-chain hydrocarbons, of which 15 to 38% were olefins. The fraction of the oil product boiling over 220 deg C was better than gas oil for diesel fuel. The solid paraffin had a melting point of 48 deg C. These materials were produced in the ratio of gasoline:oils boiling above 220 deg; paraffin of 4:1:0.2.
The Bureau report goes on
If and when natural-gas reserves are exhausted, coal could be substituted for natural gas with a gasoline cost of about 10 cents per gallon, exclusive of possible cost-lowering technological advances, according to an estimate by Hydrocarbon Research ,Inc.Should I mention that this was written in 1946?
Tonight the Montana Governor showed that the fuel produced is hard to distinguish visually from water, and stated that the fuel is more beneficial to engines than petroleum-based fuel. He also commented that the carbon dioxide produced in the process could be used relatively locally to enhance oil recovery, as we have discussed here earlier.
This is a part of a series of talks that has, most recently, dealt with coal mining.
As usual any concerns, corrections, or questions, should be addressed in comments.



I've wondered if people would feel guilty about driving a car on CTL (while wearing clothes made in sweatshops). I think the answer is no, hence the need for government to keep it in check.
Actually, not quite a direct reply, but Dave's post was so long (you should have resisted, respectfully speaking), that I didn't want to get buried 150 lines below.
I seriously suggest the governor, and anyone not skeptical of his claims, go to the home page of the Northern Plains Resource Council, out of Billings, at www.northernplains.org, and download their PDF "Old, dirty and insecure" near the bottom of the homepage.
Some talking points from it:
After that comes an excellent reference chart noting just how much water would be needed for a one million barrel/day of oil offset industry and 20.000 and 80,000 barrel/day individual plants. (which is of modest size).
One million bpd of Fischer-Tropsch industry would require half again as much water as the entire Tongue River annual flow.
I agree with your comments.
Re: "excellent reference chart noting just how much water would be needed for a one million barrel/day of oil offset industry and 20.000 and 80,000 barrel/day individual plants."
Excellent point. The same water problems apply to coal bed methane and so-called "tight gas" recovery here in the Rocky Mountain regions out west where I live. Water supplies here depend on winter snowfall and depleting deep water aquifers is not a good idea. Since climate change is bound to dry out these regions (there will be no operating ski areas in 20 years), then it seems crazy to think that large-scale oil & natural gas operations requiring large amounts of water could ever work here in the time-frame we care about (next 5 to 15 years).
best, Dave
If you don't do it the right way then others will do it the cheap way. The smog and the smells will return.
Sadly, that's what's showing in my crystal ball. And I don't like it. Not one bit.
The cynic in me sees us burning through every possible energy source at the max sustained rate, consequences be damned.
But the hopeful dreamer part wants to help avoid that future. Y'all keep up the excellent posting around coal, GW, production data, etc. As I try to influence those around me, TOD is a significant source of hard, cold data.
So.. look again in that crystal ball; I think you will see this:
not this:
Oceans are producing million times as much vapor as all human activities combined. It would be interesting though to see how GW plays on this - we can expect with rising temperatures the air humidity to grow producing a positive feedback. On the other hand the water cycle (evaporation -> precipitation) will intensify, taking away some of the energy absorbed by the oceans thus cooling them off. I have to check but probably the total efect would be neutral because it is absent in the climatographic models I've seen.
Maybe Kunstler would turn out being right that it is mostly Suburbia to blame for our worries.
Two possibilities: build a water pipeline from the East/North to the west; or ship the coal to where it will be used, and FT it there.
Any comments? Is this feasible?
Considering how much fresh water would be wasted maybe it would be economically and enviromentally better decision to build a pipeline to deliver it... just a wild idea :)
The down side of the high moisture content is you have to heat up all that water along with the coal to very high temperatures, which is inefficient and costly. You also need a lot more water for cooling.
We are a very long way from the ocean here in Montana. It's hard to judge since there are no plants in the world like what is being proposed, but it's safe to say this is an economically marginal prospect, even at a lot higher than $35 or $40 a barrel or whatever the going rate on guesses about breakeven price is nowadays.
We have no where near the extra capacity in our existing mines you'd need to supply the first plant, and we'd need tons of infrastructure (railroads, roads, hospitals, jails, towns, apartments, trailer courts, municipal water systems, drug treatment centers) for it/them, too.
Then you've gotta have a pipeline and compressors to send the CO2 wherever it is you're going to sequester it.
Can't tell you if you'd have to have a desalinization plant. With or without that, I think I'd rather buy people hybrid cars with the several hundred billion you'd need to build enough plants to replace a significant percentage of foreign oil.
If there's some left over we could spread some cellulosic ethanol plants and a couple of biodiesel plants around Eastern Montana (1/10th the investment cost per daily barrel of capacity) in amongst the windmills. That's more appropriate to the scale of economic development we need.
Western coal in general is lower sulfur than some of the Midwestern and Eastern coals, though I have not checked the numbers (they are in the EIA data files).
We have devoted some column feet to discussing how the natural gas supply in the United States is depleting. Thus the option of a Gas-to-liquid conversion may not be realistic. Further, some of the countries abroad that have been considering this have decided not to.
Bear in mind that the oil shortage will not be solved by a single silver bullet, but rather by a whole variety of bb's - of which this could well be one - all contributing their portion.
The opponent was pushing biofuel, and if I remember, the Governor pointed out that this would produce much less oil than his choice.
It is correct that the oil shortage will not be solved by a single silver bullet. Beyond efficiency (mileage investments e.g. hybrids), the question becomes what is the best investment that will be fastest, cleanest, cheapest. Montanans are also interested in something that maximizes economic benefits to local people.
Using these criteria biofuels are a better fit than F-T diesel. The Governor said that if the U.S. diverted our food crop exports, it would only replace 15% of our liquid fuel needs. However, biofuels can be produced from non-feed crops, and from perennials (e.g. switchgrass) that can be grown on acres not suitable for row crops like corn, soybeans and wheat.
The unstated assumption was that there are not more severe obstacles to producing 5% or 15% of our liquid fuel needs from coal. As you can see here, the obstacles are environmental, economic, and physical.
Conventional coal usage (as in power plants for electricity) is simply a climate change disaster happening as we speak. The governor of Montana's solution offers little else beyond boosterism of the local economy and political ambition without CO2 markets and sequestration. He says he can sell the captured CO2 and sell it to oil producers for EOR (assuming sequestration after EOR on their part) to make the whole thing work out. Really? That's a really small market right now as far as I can see.
How about something, as Monty Python said, "... for something completely different..."? Still waiting for that....
Good luck and good night.
If we respond to PO by rolling up our sleeves and getting serious about conservation, efficiency, R&D, and deploying clean technologies / energy sources, I like our chances in the long run at building a more sustainable civilization.
On the other hand, if we respon in large part with CTL and evermore ambitious tar sand / heavy oil projects, we will only dig a deeper hole for ourselves with climate change.
What concerns me more than PO is that the longer we delay option 1, the more likely we are to reach for option 2 in large measure (we'll probably see a little bit of everything) when things get interesting.
Okay, I'll stop ranting about stuff you already know and get back to work now. ; )
I have an unrelated question that I have been studying and need some help on. I keep reading in different sources that one indicator of the coming of a "peak" in oil production, or of the existence of the peak itself is volatility in prices. This seems to be the consensus opinion. The market will supposedly respond to events that cause uncertainty about the future of oil with both increased price and volatility - so the argument goes, if peak-oil is in fact becoming closer.
However, I've never seen anybody explain what price volatility is or how it is measured, never mind present an analysis of volatility over the last several years. Can anybody provide some guidance or links to price-volatility analysis?
For instance, if the price of oil goes up by 5% in January, down by 6% in February, and then up by 7% in March, does this mean the price was more volatile in February and March and therefore that the trend(from this theoretical data)is that the price is becoming more volatile? Or is my example off base? Should I be using straight dollar amounts instead of percentages?
Any help would be greatly appreciated.
Yours is as useful as any for most purposes, though. Stick to percentage change.
It's been mentioned on this site a few days ago. And Deffeyes has said -- somewhere -- that it might be useful in modeling price volatility at PO.
Yes, yes, I know that you cannot use infinitesimal caluclus with discontinuous functions; that is not the point. I am looking for the discontinuities in a rough-and-ready way.
Nobody knows how to find the point where expectations turn on a dime; my technique is just tossing a few straws into the wind.
Some aditional questions:
. Is there any study on F-T EROI? Any idea of what it might be?
. What wieght of coal is needed to make a liter (or a boe) of synfuel?
In order to assess the feasability of F-T we'll need to know if we have the needed coal reserves.
That would indicate a conversion efficiency of only 43% according to my rough calculation.
Sasol's Potential Climate Solution
Basically what I'm saying is, if even we on TOD, home of an intelligent and educated minority, can't keep a reasonanbly civilised tone and debate form, then it really doesn't look good for the rest of the planet! Maybe I am just an incurable optimist as my partner insists! Let's do our best to remain part of the reality based and rational community, without letting ourselves be provoked unduly. What's so funny about peace, love and understanding!
You're right. I do make the occasional attempt at humor (sometimes fails). I am sometimes at a loss as to what to do with ignorant trolls on the website.
A public forum has its attendant problems, doesn't it? On this thread, I would say that coal is dirty and any way you process it is going to yield lots of CO2 which can either be sequestered underground at great depth underground or simply emitted into the atmosphere. There is no getting around it.
Thanks for participating.
Only conservation is free of these issues - the only issue with conservation is if it can be done without crashing our economy (although I would think it could create whole new industries).
But as I've said before, I don't think the environmental issues will carry much weight, concerns about global warming notwithstanding. We'll do whatever it takes to keep from changing our lifestyle, until we absolutely cannot pull it off anymore. Then there will be hell to pay.
I've often said that there will be plenty for people from all parts of the political spectrum to hate, but those objections won't last long once peak oil and peak natural gas really start to have an effect.