Subjectivist wrote:http://peakoil.com/forums/underground-coal-gassification-t69418.html
Have a look, includes links for videos about underground coal gasification. They inject oxygen and water vapor and extract H2 and CO.
dissident wrote:Subjectivist wrote:http://peakoil.com/forums/underground-coal-gassification-t69418.html
Have a look, includes links for videos about underground coal gasification. They inject oxygen and water vapor and extract H2 and CO.
What a waste of energy. Burning the coal directly and producing CO2 is the proper choice.
pstarr wrote:CO and CO2 belch from the exhaust pipe of ICE's, a byproduct of combustion power-generation. It just doesn't seem to make sense that the fart can feed the animal? Right?
I think the problem with that would be efficiency. There's would be nothing wrong with recycling CO, if it was easy but I believe the problem is it's not very easy to separate still burnable CO. It would require cooling, filtering, then gas separation and even using an efficient gas pressure swing gas separation system, I doubt it would be efficient enough to be worth while to use with an internal combustion engine.pstarr wrote:CO and CO2 belch from the exhaust pipe of ICE's, a byproduct of combustion power-generation. It just doesn't seem to make sense that the fart can feed the animal? Right?
pstarr wrote:I am in no way a chemist, but this just feels craxy. CO2 is reduced. Entropy. What burns in a gasifier is the H2 and the char, ie the carbon, the C. CO2 is a waste product. How can a waste product be a fuel source?Sounds like perpetual energy to me.
ROCKMAN wrote:Interesting discussion. But we have tech to make fuel out of many substances. In the end all that matters is the net cost to do so on a commercial scale. So what is that number for carbon monoxide conversion?
Several estimates have been made of the cost of an electricity plant based on UCG syngas. The main physical variables are the quality of the coal, depth and thickness of the coal seam, linking distance of the injection and production well, distance between the cavities, and sweep efficiency. The calculations based on theoretical and actual operations point to a cost range of 1 to 8 USD per GJ of produced syngas. The main cost variation is the usage of air or enriched oxygen for injection, the thickness of the coal seam, and the depth of drilling. The later two factors determine the number of wells that need to be drilled and their required length. Oxygen-blown gasification is preferred in case of adding Carbon Capture and Storage technology.
• The estimate of Marc Mostade of Clean Coal is a production cost of 2.5 to 4.5 USD per GJ of syngas, based on a 800 meter deep 500 MW thermal size UCG plant and a coal seam of 4 to 6 meters thickness at 800 meters of depth. The difference is caused by the usage of air-blown or oxygen-blown syngas. Information about the variables underlying his calculation can be found in his ASPO 9 presentation.
• Based on the Chinese ENN Pilot a total cost of 0.9 to 1.7 USD cents per cubic meters of syngas was documented, which translates into 1 to 1.9 USD per GJ of syngas assuming a higher heating value of 9 MJ/Nm3
• In 2007, GasTech carried out an analysis of costs based on coal in the US Powder River Basin using air-blown and oxygen-blown gasification. These were estimated at a cost of 1.5 to 2.4 USD per GJ of syngas.
• In 2011, the School of Public and Environmental Affairs of Indiana University calculated the production costs for air-fired syngas via UCG in the state of Indiana in the US at 4.6 to 7.7 USD per GJ of syngas for respectively syngas produced via enriched or air, assuming a coal seam thickness of 2 to 3.5 meters at 200 meters of depth or more.
These cost levels are when averaged equal to or below the present day price of natural gas in the US, EU and Asian markets, as shown in figure 4 below. The lower cost range is on par with today’s coal price on a GJ energy basis.
ROCKMAN wrote:Sub - I feel you pain, bro, really. Such nausea is one of my worst fears. I actually feel like I've been beaten with a baseball bat. So OK: some apparent positive results with pilot projects and such. So how many commercial operations have been built... or at least under construction today? I'm not implying that it won't happen. Just that it doesn't matter until it does. Remember: I've spent four decades listening to hundreds of folks telling how their projects were going to make money. And most of them didn't. LOL.
The Soviets' UCG efforts continued, hit and miss, until the 1960s, when they were put aside by the discovery of huge natural gas reserves. One of the Soviet-era UCG sites, dating from 1961, is still in operation in Uzbekistan. In the West, there were a number of experimental efforts until the 1980s. But interest in UCG then waned—mainly because of the relative abundance of natural gas, and because American researchers learned the process could pollute nearby groundwater supplies.
Stanford University scientists have found a new, highly efficient way to produce liquid ethanol from carbon monoxide gas. This promising discovery could provide an eco-friendly alternative to conventional ethanol production from corn and other crops, say the scientists. Their results are published in the April 9 advanced online edition of the journal Nature.
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"The oxide-derived copper produced ethanol and acetate with 57 percent faradaic efficiency," Kanan said. "That means 57 percent of the electric current went into producing these two compounds from carbon monoxide.
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For the process to be carbon neutral, scientists will have to find a new way to make carbon monoxide from renewable energy instead of fossil fuel, the primary source today.
I remember a story that the wet coal gas would corrode the (black iron?) pipes but it wasn't a problem because the corrosion would swell and plug any leaks. When they switched to NG the corrosion dried out and shrank, resulting in leaks and explosions.Subjectivist wrote:as soon as they start getting water vapor out of the production side they switch back to another Blow Cycle
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