Airplanes and Climate Change?

Are you reffering to turning crops into fuel ? Like ethanol or more advanced stuff ?

I'm sure you know that back in WW2 the Nazis had a huge program making oil out of coal. I'm sure it was messy & dirty but is it possible to do this today and make it a lot cleaner w modern tech & filters etc ?

 

Not in this case. I'm talking about turning biomass (could be wood waste, corn stover, dedicated energy crops) into oil via pyrolysis or Fischer-Tropshe. Substitute biomass for Coal and it's the same process. The germans developed F-T in the 20's (Fischer and Tropsche) and used it during WW2 as you mentioned. You can apply those processes to biomass though,which would be preferable to Coal.

 

Cool stuff, where can I read more on this ?
Thanks

 

WH,

Start with pyrolysis. Once you've got that move on to Fischer-Tropsch. The coal to liquids uses F-T. I think a lot of the new biomass to liquids use a process called fast pyrolysis. Googling that term brings up several potentially interesting links.

 

excellent, Thanks

 

There are two distinct classes of airplane travel: commercial airlines and general aviation. "General Aviation" not only includes the small Cessna types, but also private jets and just about any aircraft not certified by the FAA under regulations covering airlines.

There is considerable effort being expended by both the commercial airline industry and the military to find some alternative to imported petroleum fuel for jet aircraft. The military, for obvious reasons, sees its dependence on foreign oil as a security threat; the airlines see an ever increasing fuel bill and diminishing supply.

General aviation piston aircraft are facing a looming shortage of the rare 100 octane Low Lead fuel currently used. Diesel engines are making inroads, and the flight school I work for currently has three twin engine airplanes capable of using diesel fuel but now run on Jet-A fuel, same as the airlines; diesel engines will burn Jet-A quite well. The research into alternative fuel here is focused on biodiesels. You should know that the cost of certifying a new aircraft engine is in the millions, and can take years. Because the market for these engines is very small, the cost to certify measured against the profits to be made doesn't give much incentive to engine manufacturers. (interesting commentary on human nature, isn't it, that in order to keep us from poisoning ourselves, we need to make a profit). Lycoming and Continental, the two biggies of small aircraft engines, are more likely to respond to fuel shortages than to greenhouse gas/environmental issues.

Two big problems arise, however, in trying to provide alternative fuels:1. For jet engines, at the cold of high altitudes, current formulations of biodiesel would turn into gelatinous masses unless the tanks were heated which both increases the cost and complexity of the system and introduces a new level of risk (heater failure, fuel gelling and engine starvation). Experimental formulations of biodiesel are ok at temps as low as +12deg F, but at 35,000 feet, the temperature averages 60deg F below Zero. 2. For gasoline piston engine aircraft, at present, there is no adequate substitute for gasoline. Ethanols are less energy dense, requiring larger tank capacity to deliver the same range, and with less climb performance. Ethanols are also subject to freezing at high altitudes. Some high performance piston engine aircraft can reach altitudes in the low 20s, where the outside temperature would be about minus 40 degrees F.

I've been nutty on this issue for several years; my partner and I are committed environmentalists (he is a local expert on biodiesel). My flight school currently operates the most fuel efficient airplanes in current production, and our syllabus relies much more on simulators than it used to. I can live with this for the present, especially knowing that management is concerned about environmental and financial aspects of our fuel use.

The reason more isn't being written about fuel issues and the global warming effects of airliners is (as was pointed out in another post) our near absolute reliance on air transport and our refusal to confront the issue head on. I have seen articles in Flying, AOPA Pilot, and other aviation magazines, but not much in the general media. The effect of small piston engine general aviation airplanes on climate change is miniscule; there are not very many small airplanes to begin with. The effect of jetliners, however, is much more serious, not only because of the enormous quantity of fuel used, but the altitudes at which that fuel is burnt. At high altitudes, the production of greenhouse gasses is more efficient. As beautiful as the Concorde was, I don't rue its passing; it was a hideous environmental disaster.

 

The vast majority of air travel is due to the convenience of cheap air fares, not necessity. It's economics that created the crowded airways....and it will be economics that will reduce the crowding if this is what is needed.

The other lesson of 9/11 was to show that business (except airlines obviously) can still run without air travel. There was LOTs of hardship, but not collapse.

Not mentioned was how dense the airways are already. The only way air traffic is going to increase is to allow the plane spacing to decrease from the present day values. It's really crowded up there.

 

Well, it's not really that crowded. I've flown around up there (including in the L.A. basin, which has more planes per cubic centimeter than probably anywhere else on Earth), and there's still a lot of room. The sky is really big!

As you say, changing the rules will fix the air traffic "crowding". More direct routing and some (expensive) software will solve that.

The real bottleneck right now is the departure and arrival points. The current hub system is becoming more untenable with time. We'd need more hubs or more direct flights with fewer seats (and therefore a little more expensive).

In addition, a lot more telecons/videocons and more virtual touristing would be a good idea.

 

Why you would want to stop air traffic is beyond me. If you want to live in the 19th C move into an Amish Village

As for efficiency, a new blended wing design for airliners thats appears similair in shape to the B2 bomber improves efficiency by 25%. Several of these designs have been created by NASA, Boeing, and MIT

combine the new design with modern very efficient turbofans and your fuel usage will plummet

They say this aircraft will actually be 4 mpg more efficient per passenger than a Prius

 

The ultimate point is how does one fly around when the gas is gone? Could there be a Hydrogen option? Or when gas gets expensive would aviation get the first priority...or the last priority?

My crystal ball (which has never worked well) is rather cloudy on these issues.

 

The air traffic controllers that I have talked to don't have the same opinion. (Their opinion, not mine.) Likewise, the burden placed on private pilots has continued to increase to the point where flying for personnel travel is getting too painful to sustain as an individual.

Your post is sensible from a passenger aircraft viewpoint, but with companies like Eclipse Aviation, Honda, and others getting into the Lightweight Jet market, this room will be used up fast....with private/general aviation getting the short end of the airspace.

 

If it's only 25% more efficient, then it would be a few mpg more efficient than a Prius with one passenger. A Prius with four passengers is about four times as efficient per mile than a current commercial aircraft per seat.

Even so, you're unlikely to drive your Prius for four to five days across the continental US when given with the alternative of a five-hour flight for a few hundred bucks.

Though a four-passenger car with one passenger and a seat on a plane are comparable per mile, the planes end up dominating my carbon budget since they can cover so dang many miles so fast and so cheaply. My Prius put out about one tonne of C last year. My commercial flying put out 2.7 tonnes C, and my family on our vacations added another 3.4 tonnes, for a total of 6.1 tonnes.

 

We can produce liquid fuels suitable for aircraft using solar / nuclear heat and generated electricity, and water and carbon dioxide from the air. Either methanol or dimethyl ether. The efficiency isn't great, but it isn't awful either. That can provide sustainable liquid fuel for aircraft indefinitely, and would be carbon neutral.

 

Under the current air traffic available data and operational rules, yes, they have a very tough job. But there's no reason with the planned scheme (instead of RADAR, using GPS receivers on each aircraft broadcasting their exact position and velocity), that the routing can't be vastly simplified from the point of view of the controllers. There really is plenty of room up there.

I'm a private pilot, and so far I'm not complaining. I'm not sure what burden they're talking about.

 

1st jets dont use gas, they burn kerosine

then of course you have gliders which dont have any engines

then you have solar and human powered aircraft

There were designs for nuclear powered bombers and one flew w a reactor in it but the reactor was never turned on

and of course in WW2 the Nazis flew plenty even jets w fuel made from coal

 

I'm not sure what you're responding to. Anyway, my ratios are on the basis of carbon emitted. Since gas and kerosene are both approximately CH2, the ratios could also be considered on the basis of heat content of the fuel.

I couldn't figure out if there was a point to the rest of your post.

 

Sorry madler, I was replying to FL_Prius

and the article stated the new aircraft was about 25% more efficient than the best current airliners, not the B2

sorry for the miscommunication

 

I see you are from Pasadena

are you with JPL ?

 

Yep.

 

Conceptually, that could work. It would make it even more tightly interlocked, so a accident could have big ripple effects. However, at 50000 deaths a year on the road, I really could not make a point that it would be more dangerous than driving. Not even close.

Vastly more airspace classified as restricted is one of the major points.