SHEC to Build Solar Plant to Convert Landfill Gas to Hydrogen
07 December 2005
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| Sketch of the solar station |
Solar Hydrogen Energy Corporation (SHEC) and its partners will deploy the world’s first solar hydrogen production station using landfill gas (LFG) (methane) as a feedstock at the Fleet Street landfill in Regina, Saskatchewan.
The plant (SHEC Station #1), based on SHEC’s Dry Fuel Reformation process—will use an array of 30 modules each of which comprises a solar mirror array and advanced solar concentrator and shutter system, and two thermocatalytic reactors to convert methane, carbon dioxide, and water into hydrogen.
SHEC Station #1 will have the capacity of producing 1.2 million kg of hydrogen per year (40,000 kg/module) and has a projected 40-year life.
The Dry Fuel process essentially substitutes solar heat for the steam heat used in steam methane reforming. SHEC feeds carbon dioxide (CO2) and methane (CH4) into a reactor heated by a solar mirror array where the gases react to form hydrogen gas (H2) and carbon monoxide (CO). A water cooled iris dilates to control the amount of radiant energy directed to this reaction phase.
The intermediate products feed into a water gas shift reactor (WGSR), controlled at near atmospheric pressure. The resulting gas stream contains H2and CO2 and is saturated with water.
In a demonstration unit, SHEC’s Dry Fuel solar hydrogen generator operated for approximately 1,200 hours with no noticeable coking or degradation of the catalysts. Hydrogen production is near the theoretical maximum at approximately 66% in the product gas stream with a 98.2% mol conversion of the feed methane.
Landfills account for approximately 25% of greenhouse gas (GHG) emissions in Canada. The SHEC project will reduce Regina’s GHG emission by 25% bringing the city close to the Kyoto requirements in this one project alone.
This first project will prevent more than 1.6 million tonnes of carbon dioxide equivalent (CO2e) from entering the atmosphere over the next twenty years and will significantly improve local air quality and reduce smog.
The Dry Fuel process can be used with biogas, flare gas and vent gas from the oil and gas industry, stranded gas, coal bed methane and conventional natural gas as well.
SHEC’s partners in the project are Giffels Associates Limited (Ingenium) and Clean 16 Environmental Technologies, working in conjunction with the University of Toronto Department of Chemical Engineering and Applied Chemistry.
SHEC is also targeting solar-driven direct water splitting and biomass conversion as pathways to hydrogen production.
Now that is a worthwhile advance. Converting CH4 + 2 H2O to CO2 + 4 H2 converts a mole of methane at 213 kcal/mol into 4 moles of hydrogen at 70.6 kcal/mol is an increase in energy of about 1/3. SHEC claims 3.9 volumes of hydrogen per volume of methane, so they are getting most of that boost.
I recall something like this being proposed many years ago as a way to make fuel for the US Navy; I think it was on the cover of Popular Mechanics. Here we are, reading about it coming from Canada. Are you listening, Washington?
Posted by: Engineer-Poet | 07 December 2005 at 04:30 PM
Methane is 23 times worse as a greenhouse gas. Does converting methane that would otherwise go walkabout into H2+CO2 have a net reduction in global warming even releasing the CO2?
Next question is... Why convert to H2? Can't the biogas be used to power a turbine at a higher efficiency rather than cracking the methane into H2?
Posted by: Lance Funston | 07 December 2005 at 05:30 PM
In this case, no. The thermal cracking process increases the chemical energy of the products, so the hydrogen has about 29% more energy than the methane input.
This would be even more slick if other sources of methane were thermally "hopped up" to stretch them. Perhaps California could do something about their gas-fired generators; if they had a source of CO2 to feed this process, they could use solar cracking to cut their natural gas requirements by about 23%.
Posted by: Engineer-Poet | 07 December 2005 at 07:47 PM
And I just realized that CO2 can be recovered from the products of the shift reaction and recycled to the cracking process.
Posted by: Engineer-Poet | 07 December 2005 at 09:58 PM
In Canada?? I wonder whether this can be cost-efficient, considering annual irradiation and the not too cheap infrastructure. Further in the south it could be used more efficiently, I guess.
Posted by: Ray | 08 December 2005 at 04:12 AM
Canada in the summer can have as much as 18 hours of daylight per year. The number of daylight hours per year is not dependent on latitude. This is one way to store summer energy for use in the winter.
Posted by: tom deplume | 08 December 2005 at 07:49 AM
Of course, for the direct use of solar irradiation it is most important to have cloud-free conditions. Still, latitude does have a big influence on the total energy you can harvest annually. The highest potentials lie roughly between 10-30° latitude. I am just asking myself: If such a plant can be economic (these solar concentrators are simply not cheap), why aren't similar plant concepts built where more energy can be harvested, also in winter?
Posted by: Ray | 09 December 2005 at 04:20 AM
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Posted by: Ayele Thalema | 09 December 2005 at 04:21 PM
It would be interesting to know how much of the focused solar energy is captured as chemical energy in the hydrogen output.
Using the figure of 40,000 kg H2 / year for each module, I get 20 million moles H2 /yr, which I believe is an average of 2/3 moles / second over the course of a day. If the gain in chemical energy is 17.3 kcal / mole of H2 output, that's 11.5 kcal / second per module. If the 17.3 kcal / mole is correct and I haven't botched a conversion somewhere, that's a rather astonishing energy gain rate of 48 kW per module. Astonishing, because that's the average over 24 hours; since it actually produces only during sunny daylight hours, that probably means about 150 kW / module during operation. That's 100% of the focused sunlight from a 12 x 12 meter mirror.
Could the modules really be that big and that efficient? Doesn't seem likely. I must have botched the calculation somewhere.
Posted by: Roger Arnold | 09 December 2005 at 10:46 PM
I can't find anything at SHEC's site which says how big the modules are or how much solar input is required to process a given amount of gas.
Maybe if you look at it you can find it.
Posted by: Engineer-Poet | 11 December 2005 at 10:21 PM
"Landfills account for approximately 25% of greenhouse gas (GHG) emissions in Canada"
I am slightly skeptical of this claim, considering that Methane only accounts for about 18%(can't find the exact figure) of global warming, and is released into the atmosphere from many other sources such as agraculture, natural gas leaks, and resovours. Probably all methane sources account for 25% of GHGs in Canada. The CO2 from landfills is probably negligable.
How would this process compare to steam reforming of methane? Does steam reforming have a net energy loss?
Posted by: me | 12 December 2005 at 05:18 PM
Yes, steam reforming is a net energy loser. Anything which adds energy is quite an advance.
Posted by: Engineer-Poet | 15 December 2005 at 10:08 PM
How much methane per year would need to be collected to meet the 1.2 million kg mark ?
Market price per Kg ?
What is the market price for methane ? and the price negotiated for this project ?
How much electricity could be generated from the methane ?
This is interesting stuff, hope you can answer my questions.
Posted by: Reggie | 06 January 2006 at 09:12 PM
Yes SMR typically loses 30%-35% of the energy of the methane that is inputed to the process.
Posted by: SMRKid | 15 February 2006 at 04:52 PM
hydrogen and methane are about equal as vehicle fuels:
one third of the energy in h2 is used to compress it to 10,000 psi in the on board vessel.
methane can be stored as LNG at atmospheric pressure or CNG at 250-3,000 psi
so does not incur 1/3 energy of storage penalty,
but does incur a 1/3 drop in energy from pure hydrogen.
then the tie breaker in favor of methane is that it can be used in CNG vehicles.
This is A great advantage, since we will be waiting twenty years for affordable Fuel cell cars.
If the methane was made from solar cracked H2 from water, combined with atmospheric Co2, in the sabatier reaction, then
the methane fuel would be carbon neutral,
even when burned in an internal combustion engine.
the point is to think of methane as a convenient way to store solar hydrogen,
that obviates the need for expensive compression or liquifaciton of H2, and thier attendant bulky insulated H2 gas tanks.
Posted by: robert carlson | 07 June 2006 at 05:16 PM