Two Coal-Fueled Ethanol Plants Under Construction
04 November 2005
Two ethanol plants under construction in the Midwest are apparently vying (indirectly) to become the first coal-fueled ethanol plants in the country.
Each plant has a 50-million gallon per year production capacity, uses corn as the feedstock and will use coal combustion as the direct energy source for steam and drying. The decision to go with coal was based strictly on economics; the groups calculate they will thereby reduce their production energy costs up to 70% compared to using natural gas.
The Heron Lake Bioenergy project (Heron Lake, Minnesota) is due online in the spring of 2006. The Red Trail Energy project (Richardton, North Dakota) is scheduled to open in November 2006.
Heron Lake plans to use Powder River Coal (lower in mercury and sulfur), mined from the North Antelope Rochelle Mine in Campbell County, Wyoming. Red Trail will use North Dakotan lignite coal.
Planned combustion and emissions management is conventional. The Heron Lake plant, for example, will use fluidized bed combustion, a technology that Interior Department’s Office of Coal Research, one of the forerunners of the Energy Department, began studying in the early 1960s.
Fluidized beds suspend solid fuels on upward-blowing jets of air during the combustion process. The result is a turbulent mixing of gas and solids. The tumbling action, much like a bubbling fluid, provides more effective chemical reactions and heat transfer.
Fluidized-bed combustion evolved from efforts to find a combustion process able to control pollutant emissions without external emission controls (such as scrubbers). The technology burns fuel at temperatures of 1,400º to 1,700º F, well below the threshold where nitrogen oxides form (at approximately 2,500º F, the nitrogen and oxygen atoms in the combustion air combine to form nitrogen oxide pollutants).
The mixing action of the fluidized bed results brings the flue gases into contact with a sulfur-absorbing chemical, such as limestone or dolomite. More than 95% of the sulfur pollutants in coal can be captured inside the boiler by the sorbent.
The coal combustion will, however, still produce mercury, dioxin and other emissions and require mitigation.
Resources:
If nothing else this will certainly allow people to claim that ethanol is a dirty fuel, like coal fired electricity generation is dirty. Too bad they can't be made to use ethanol as the source of energy, after all it's supposed to be clean!
Posted by: Schwa | 04 November 2005 at 06:45 PM
Why not use some of the ethanol that they make to fuel the plant? Perhaps it takes more energy to make the ethanol than they get from the ethanol. Let's hope not.
Posted by: tthoms | 04 November 2005 at 09:20 PM
If they fueled the plant with ethanol, they'd use upwards of 40% of their output.
Neither site mentions electric generation. What a waste; if a gallon of ethanol takes 33,000 BTU of heat to produce, a 50 million gal/yr plant with a 25%-efficient steam plant using the spent steam to heat the mashing tuns and the stills would produce 550 billion BTU (161 million kWh) of work from the turbine. That's 18.4 megawatts, a non-trivial amount of power.
Best of all, the extra coal it burned to make electricity would displace about 3 times as much coal (and its toxic emissions) from another plant. And they're not doing it. That's a crime.
Posted by: Engineer-Poet | 04 November 2005 at 11:28 PM
With the NOx emmision from coal this is a good thing?
Are they going to recycle the emissions or gasify the coal?
http://www.pbs.org/saf/1506/video/watchonline.htm
Shows how we can recylce NOx reducing he emissions to
something not harmful.
Bob
Posted by: Bob | 05 November 2005 at 06:31 AM
From a conservation standpoint this is certainly much more logical than burning natural gas, or a liquid fossil fuel. And I presume that coal-fired-ethanol produces more liquid fuel per ton of coal & etc. than coal-to-liquids.
And hey, coal's cheap.
The only thing to watch (as everybody notes) is that the emissions are handled in the best possible way.
Posted by: odograph | 05 November 2005 at 08:06 AM
Once again, the decision to use low cost high pollution COAL, to produce the heat required, was admittedly based strickly on economics. The same argument is going to be used over and over again, specially in China and the USA, where abondance of cheap low grade polluting COAL exist, to produce low cost heat and electricity for the next 50 + years. Those operators purposely ignore the enormous downward cost of the pollution created by CAOL burning.
With such an approach, we may as well continue with ICE vehicles to the last drop of OIL. Burning fossil fuel directly in vehicles with cleaner more efficient diesel engines may not produce much more pollution than with COAL produced corn-ethanol.
However, most of the heat required could be supplied by nearby or remote high efficiency wind farms, complemented when required with natural gas, to produce corn-ethanol with much less pollution. Short term cost and savings forbid?
Posted by: Harvey D | 05 November 2005 at 08:14 AM
I have worked in "emissions monitoring" for the electric power industry (gas and coal fired). I'm aware that there are plants ranging from semi to very dirty. I'm also aware that the working engineers and plant operators are happy to satisfy air quality regulations. The working stiffs like to be "pushed into it."
Unfortunately top management has this strange need to lobby government for reduced regulations. Silly, because coal is still going to be "cheap" even with emission controls.
Wind & stuff is great. We'll need it too. Go ahead and build as much as you can ... in my back yard if you want to.
Have you really figured out a way for it to provide base power production across the whole country though?
Posted by: odograph | 05 November 2005 at 08:57 AM
How about combining wind and solar with the production of electricity from the production of charcoal from biomass, e.g. grass
Storage is the bugaboo here, but if you've got ice storage for your A/C (so calm/cloudy days just run fans and pumps) and 100 miles or more of electric range in your GO-HEV (so you can go a couple of days without charging), you can just wait for the wind to blow again.
Posted by: Engineer-Poet | 05 November 2005 at 10:08 AM
No doubt all those happy campers driving around in the F 350s using ethanol will be touting how environmentally sensitive they are. If we have to burn coal to get ethanol, let's just forget it. I don't care how clean they claim to be, they're not going to get rid of the carbon dioxide. With respect to global warming forcings, cleaning the coal of negative forcing like aerosols, but not sequestering the CO2 may be worse than just burning the coal without controls.
Posted by: t | 05 November 2005 at 11:28 AM
Does it truly make sense from a conservation standpoint? What about all the petroleum used to produce the corn?
Posted by: tom | 05 November 2005 at 11:33 AM
"No doubt all those happy campers driving around in the F 350s using ethanol will be touting how environmentally sensitive they are."
So tax the ethanol, or the F-350s, but don't ignore the physics.
"Does it truly make sense from a conservation standpoint? What about all the petroleum used to produce the corn?"
It would be nice to cut the subsidies and see how it holds up.
Posted by: odograph | 05 November 2005 at 11:56 AM
The combination Wind-Hydro seems to be ideal. Hydro water reservoirs become huge energy stores (batteries) to be used when wind energy slows down. This combination allows the use of more over-equipment at hydro sites to handle peak demands. Large Wind farms are being built close to existing hydro power lines for that purpose and cost effectiveness. The existing 40 000 + megawatts of installed hydro power in our province will be coupled with 20 000 + megawatts of wind power within a few years.
As hydro power builds up towards full potential of 70 000 + megawatts, wind power will be increased proportionally. Wind power potential is about 95 000 megawatts. By 2020/2030 we could (if the market is there) produce between 2 and 3 times the electricity we need and export huge amount of CLEAN electricity to our immediate neighbours and to USA east coast where the price is much higher.
This cheap (less than 8 US cents/KWh) surplus CLEAN electricity could be sufficient to satisfy 50 + million PHEVs at about 10 KWh each per day for a very long time (indefinately?).
Posted by: Harvey D | 05 November 2005 at 02:08 PM
This is where a CO2 licence could work out. It may be true that with joint fuel and electricity co-production each ton of coal could create more bang for a buck in energy terms. Since overall CO2 would be capped the most profitable coal users would outbid the staight coal users who would be forced to cut back or change their technology. In a world of mainly clean energy there may still be room for coal provided the overall CO2 cap isn't exceeded.
Incidentally in Perth, Western Australia the new sea water desalination plant was to be powered by a coal station but the power plant will now be a wind farm.
Posted by: Aussie | 05 November 2005 at 02:52 PM
Either make ethanol with existing waste heat or forget about it. The WASTE heat of a nuclear plant (or other symbiotic industrial process) can be used instead of burning anything. Coal is about the dirtist thing I can think of, and natural gas is just too precious. So many industrial processes make waste heat or steam, including electrical generation. Just put them together.
Posted by: little shop | 05 November 2005 at 07:57 PM
Wasn't there a post a while back that reported a plan to gasify coal, cooling the syngas by making steam to generate electricity, then bubbling the syngas through a bacterial culture which produced ethanol?
Posted by: tom | 05 November 2005 at 08:17 PM
Yes, tom, there was. On one hand, the process was not terribly efficient; on the other hand, getting rid of waste saves money even if you turn it into nothing.
Posted by: Engineer-Poet | 05 November 2005 at 08:41 PM
Rather, it was a scheme to gasify trash, not coal.
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