One hopes that this caliber technology becomes the base level for all new power plants burning carbon fuels. IGCC sounds highly promising if it can actually do what it claims. Long term problem with coal gasification project is the non-sustainable component. However as a relatively clean source of electricity and H2 - it seems good.

The LCSF tubes apparently need high temperatures to work their magic. I wonder if they could be used to remove virtually all of the oxygen from the raw exhaust gas of a lean-burning ICE (diesel, CNG or stratified GDI). If so, a cheap regular three-way catalyst might be sufficient to meet emissions standards. A DPF may also be required when combusting diesel fuel, possibly upstream of the LCSF tube.

The pure oxygen produced would usually be vented into the atmosphere. However, during engine warm-up and transient acceleration, it might make sense to feed some of it back into the intake after intercooling in a stainless steel heat exchanger. Doping the fresh charge with extra oxygen would yield extra power during transients, with the higher exhaust temperatures reducing turbo lag. This would permit the use of a smaller, lighter, cheaper engine in LDV applications for which part load is the regular case. The extra NOx produced due to the oxygen doping would be taken care of by the three-way catalyst and a slightly rich mixture.

Presumably the tube oxygen separator has a lower power requirement than the pressure swing zeolite method, but the article doesn't say how much. I also note that it envisions gasified coal which is also mentioned by some fuel cell researchers. However if the tests use lab quality methane that is a lot different to gas containing particulate and sulphur.

With regard to the LSCF oxygen separator tubes, maybe someone can help me out. What I don't understand is this. If they have a tube which is permeable enough to oxygen at regular combustion temperatures for this purpose, why wouldn't they just use it as a standalone oxygen separator? The incoming air could be heated with waste heat using a heat recovery heat exchanger, pressure would be applied, and you would draw oxygen out of the tubes. This could then be fed to a separate turbine generator that burns gas/hydrocarbon fuel at a really high temperature, using ceramic turbine blades, giving unrivaled turbine efficiency (perhaps even better than fuel cell) without the traditional NOX barrier getting in the way. The CO2 is ready to sequester. NASA by the way has done some very interesting work in developing silicon carbide fiber composite turbine blades, so that part of the technology is available.

It looks to me like the connection between these two clever innovations is that they're direct competitors. Though in practice one would be used for radical new designs and the other for retrofits.

Combustor technology isan art formas much as a Science i n my experience. There has been lots of money invested in precisely htis ara. I questioon whether thsi is rellynew ,but if it is counter-intuitive to current best-design practice, it may well be so. Technology advances in expected and unexpected ways.

Regarding the gas seperator, I wonder what the permeability is at working temperature. It would have to be pretty high to overcome the work inefficiencies in separating the O2 from N2. Not all N2 oxidizes; in most controlled combustion, If I am correct I suspect that only a tiny per centage does burn. It may still be better to seek out and control that tiny percentage than to separate 20% (O2), of the inbound air flow from its other 80% (N2).

P Schager

Excellent point.

Though I cannot claim to know the answer, I think, 800 degree C is too hot for intake air. Also, the technology of pure oxygen cobmustion is nor developed yet. Gases burns more vigorously in pure oxygen and produce more heat. A completely new engine needs to be developed to enable pure oxygen IC engine.

Are there lower temp methods for separating the oxygen and nitrogen? I thought I have seen a poly cartridge tube. My interest is to reduce the nitrogen prior to going into a gasification process. The shell and tube method is much preferred if the pressure delta is not too high.

Regards, Toby Seiler

@ SM -

I'm not entirely sure your statement is correct. The amount of heat produced depends on both the available oxygen and the available fuel. If you have a global excess of oxygen, as you do in a diesel or stratified GDI engine, the unused portion merely ends up in the exhaust. Apart from the risk of accelerated oxidation, the only problem it causes there is that NOx cleanup becomes much harder; however, if there was no nitrogen in the intake gas, no NOx will be produced.

So, if pure oxygen were available and the engine construction sufficiently strong, you could achieve higher specific power (i.e. smaller and/or fewer cylinders). This may reduce engine weight and/or internal friction - presuming your oil is up to the job. For a given absolute power level, the total air mass flowing through the air filter would be comparable. However, the nitrogen would bypass the engine rather than pass through it.

The main reason you actually DO want a significant fraction of inert gas in the fresh charge is a different one: it slows down combustion. Near-isochoric heat release (cp. HCCI) is thermodynamically efficient but it also generates very high mechanical stresses and combustion noise levels. Unfortunately, the inert gas that's already in the atmosphere is nitrogen, which oxidizes at the high temperatures encountered in flame fronts.

Thanks Rafael, I was wrong on the "more heat" part. My main point was, a new type of engine needs to be developed to use pure oxygen - which I think you confirmed.

If pure oxygen is used in combustion for steam power plants, the combustion temperature can be much higher than with air. This can increase the efficiency by not needing to heat up and release hot nitrogen to the atmosphere as well as having a higher temperature to super-superheat the steam. It might even be useful to have a closed cycle steam compressor-turbine at low pressure and high temperature as a topping cycle. Several power plants attempted to use mercury vapor at the highest temperatures because steam at those temperatures has very high pressures and mercury does not. While new materials and technologies would prevent the release of any mercury vapor, such machines are now politically incorrect. Sodium vapor is much harder to deal with than mercury but its use in producing electricity with AMTEC cells (High pressure sodium forced through sodium ion conducting alumina at high temperatures.) would be facilitated by the higher temperature of pure oxygen combustion. Waste heat at very high temperatures from the AMTEC cells would be used to run regular steam turbines. Pure oxygen cannot be used in combustion turbines because the high temperatures would melt or otherwise destroy the combustion chamber and turbine blades. The oxygen could be diluted with steam or cooled recycled exhaust gas to lower the temperature as is done now with piston engines to lower the NOX production. Piston engines cannot withstand the temperature of the pure oxygen combustion either. The use of nitrous oxide, with its increased oxygen content stresses most engines as it is.

I am also interested to see if such tubes can produce pure oxygen gas.

This ceramic material allows for a simple zero pollution car to operate on the road and burn any liquid fuel. After combustion the exhaust gases are fed to a compressor that allows for the water to be condensed into a liquid and the carbon dioxide to be also condensed if the temperature is less than 88 Farenheit, 31 centigrade. There is enough space in a car to store the CO2 under pressure, even if not liquified, until it can be dropped off at a service station. Multiple small pressure tanks can be installed in free space and even pressure tubes could be used as structure elements. The tanks or tubes can be made of cheap steel or lighter materials if the expense can be tolerated. The water can be released or saved. Cooling the CO2 to liquid in hot climates may not be necessary. Evaporating the liquid water into dry air might provide some cooling.

The high temperature combustion can be used to operate a small stirling engine generator with heat pipes. Batteries with a ten mile capacity and high power are all that are needed; such batteries are made today even out of lead. Just a single extra Prius battery installed in a Prius with electronics that can put its full charge into the regular battery when needed would give the Prius 30 miles of extra full electric range.

The car could fuel up at service stations every 200 or 300 miles and drop off its CO2 while picking up more fuel. Any liquid or gaseous fuel could be used, but ordinary liquids like ethanol, vegetable oils, diesel, heating oil,colman lantern fuel, methanol and filtered used motor oil can all be used and compensated for by the car computer and oxygen sensor. No special qualities like octane rating or cetane rating or volatility are needed. There is no reason to make biodiesel, as the original oils can be used. A separate tank for some starting fuel could be useful. Even pure carbon nano particles suspended in a fluid could be a fuel. The fluid could be CO2.

A cheap simple steam car could be built to demonstrate the technology. A steam car with a vacuum insulated tank and home plug in electric heaters would have the instant take off capability. Fuel powered heaters could also keep the steam hot.

Fuel powered heaters are now built into some European diesel cars that are so efficient that enough heat is not produced to keep the car and engine warm at some cold temperatures. They might even have to invent exhaust gas heat recovery.... HG....