quite a nice breakthrough, if it, eh, breaks through
I quite fancy the prospect of them adding deep-fried Mars bars to the in-flight menus.
Aircraft maker extraordinaire Boeing has joined forces with its Chinese equivalent to engineer a way of converting discarded cooking oil into aviation fuel. The project is being overseen by Hangzhou Energy Engineering & Technology, an alternative energy specialist, at a brand new R&D centre set up by Boeing and Commercial …
I think it's a bad idea myself. The plane takes off and the faintest whiff of cooking oil floats through the cabin, putting you in just the right frame of mind for a fry up and instead you get served an undercooked chicken swimming in a sauce technically described as "red shit".
If it pollutes the air more than what they already have, what good is it?
Consider the total cycle. Recycling used cooking oil into aviation fuel could reduce demand for aviation fuel refined from crude, and the total energy and environmental cost of the recycling process could be less than the total cost of the refining (from crude) process. Evaluating it just on the basis of a single metric (such as air pollution produced by the final consumption stage) is misleading.
I don't see why used cooking oil isn't ALL being turned into diesel already, not just in China but everywhere. Diesel doesn't have to be as high-quality as aviation fuel, and the conversion process is extremely simple (I know a guy who does it in his shed and has been running his 4WD on it for years).
Maybe the cost of making diesel from fossil fuel is cheaper than making it from free used cooking oil?
I think the problem with large scale use of cooking oil is one of collection. You'll need to operate a fleet of tankers and relatively local sites to do the processing, and I think this is what makes it uneconomic rather than the costs of the process itself.
Just how much cooking oil will it take to get a single 747 from London to New York? A lot. Unless there's some other application for this process, I'm inclined to view it as publicity material rather than anything that has a practical application in aviation.
"Almost all of our restaurants recycle their cooking oil in this way, and those that can’t at the moment are working hard to make it possible. For example, our restaurants in Northern Ireland plan to convert all of their oil by the end of 2012."
"I think the problem with large scale use of cooking oil is one of collection."
After several years of paying people to take away their used vege oil and locking them into supply contracts (which means that hobbyist can no longer obtain WVO easily), most of the collectors are now charging to take the oil away.
The collection mileage makes it much more economic to make the diesel from cooking oil locally. Given how simple the conversion is, and that I also know someone who drives his car this way using a plant in his back garden, use of cooking oil for locally-produced diesel seems to make much more sense. Mind you, those doing this need to be careful about the use of methanol - it's a highly toxic substance.
It could all be used for fuel.
The process cost is tiny for biodiesel production, for me it's 10 pence per litre all in (chemicals and electricity for heating/pumping/Methanol distillation) and I'm not doing it on a large scale. The main costs are the feedstock and duty. I'm constantly being pestered by Chinese companies trying to sell their used oil in 14 ton loads, so they must have lots of it if they're willing to ship it around the world.
I can see the problem with aviation being the variability of the feedstock, and the many thermal characteristics of the final fuel. Unlike fractional distillation which gives nice uniform grades of hydrocarbon, biodiesel has a wide spectrum of fatty acid chains, each with their own cold filter plug points. Add in problems with oxidisation to contend with and it can be a world of pain. Sadly theregister article is a bit light on the technical details of what this company are doing that would address these issues.
As fossil fuels start to become unaffordable for the volume market, we will have better things to do with the remaining supplies than using them to fly tourists and businesspeople around the world in Boeing and Airbus craft powered by precision engineered aircraft turbine engines which require precision engineered fuels to deliver decent power to weight and decent maintenance intervals.
Someone might perhaps want a supply of nice clean fossil fuels for military aircraft rather than civil aircraft,'cos there'll surely be wars to think about.
We might also want lots of (not necessarily quite as clean) fossil fuel substitutes for feedstock for the petrochemical industry. No cheap petrochemicals => no cheap fertilisers for industrial-scale agribusiness, no cheap plastics for anyone, won't that be fun.
But reprocessed waste cooking oil for civil aircraft makes neither engineering sense nor economic sense.
Half the energy in cooking oil is thrown out when you esterise it to make diesel, plus you end up with a mountain of glycerine and akaline byproducts to dispose of.
It's far more efficient to use the oil directly and turbine engines can eat anything from methane to coal dust (what do you think they feed 'em in power stations?), so no (or only minor) modifications are needed for the flame cans.
For the same reason it's far more economic to convert cars to run on vege oil (modification performed once) than to continuously convert oil to biodiesel and dispose of the byproducts.
Making biodiesel out of any kind of cooking oil is NOT "green" or efficient when diesel engines can quite happily handle the raw product with only minor modifications. The environment agency only puts up with people doing it because it's slightly less damaging than having people dump their oil down drains or into landfill.
Yes, I'm arguing for tighter regulation of biodiesel manufacture - and that's despite having a WVO converted car. If making the stuff becomes associated with toxic waste because of cowboys and backyarders then the entire reuse will become regarded with suspicion. By way of comparison, by using filtered WVO directly, I end up with less than 1% byproduct (mostly heavy animal fats and flour from batter plus the odd fish in the oil) which makes a good base for bird suet - end result =no toxic waste to dispose of.
"It's far more efficient to use the oil directly and turbine engines can eat anything from methane to coal dust..."
Actually Mr. Diesel also planned to run his engine on solid fuels such as coal dust. His patent, US 542,846 specifically mentions "... any kind of fuel, whether solid, liquid, or gaseous." and "Solid fuels may be introduced in a pulverulent or comminuted condition." Granted, ground up pre-diamonds are probably hell on the piston rings and cylinder walls and probably accounts for why there aren't too many conspiracy theories about the oil companies killing the coal dust diesel that gets 370 miles per firkin of coal dust or in local units 442 Brontosauruses / Brontosauri per Jub.
... and the junk from the grease-traps helps to power a slightly modified 25KW Generac gen-set during power outages, and one of the Kubota tractors. Burning hydrocarbons to drive pistons and/or spin generators ain't exactly rocket science.
Mind you, I'm not flying my local power-plant or Kubota ... The aircraft have somewhat more reliable fuel supplies. You picks yer battles & takes your chances ;-)
we take used cooking oil and then spend money and generate pollution converting it into a taxable product when it can mostly be used as is. Maybe not for cars but as far as I can tell cooking oil will burn just fine in an aga and I've see a design for burning the oil seed rape seeds more or less as they come off the plant with just a couple of prods a day to keep things moving.
You can use it directly in landrovers (I do). Apparently it can cause some problems but I've yet to have any. The real reasons of course that cover why its not more widely used can be summed up as greed.
The oil companies are desperate to keep their captive audience of profit producing users. These companies are worse than any cocaine or heroin dealers in that regard. This accounts for many of the scare stories and of course much of the legislation preventing you trading in the stuff for the purpose of using it to drive cars.
The governments are panicing about their tax take. You can see this all over europe at the moment with the plethora of talk about 'congestion' and 'road' pricing. The ONLY reason to introduce road pricing is to tackle the chance of the motorist finding an alternative to the massive tax burden imposed on fuel by european governments addicted to tax and spend.
"There's great potential for converting the waste cooking oil into sustainable aviation fuel."
No there isn't. If there was, you'd be hearing about it from an engine manufacturer talking about it as a commercially viable exercise, not from a planemaker running it as a desperately needed PR exercise.
Martin Budden and jake have both spotted that there are much simpler ways to reuse cooking oil. These are also ways which aren't likely to knacker the very expensive, safety-critical, engines when something goes wrong in the reprocessing.
Remember it's not all that long since Heathrow nearly had a crash because a big one had a multiple engine failure because the fuel filters got clogged with ice because the plane had stayed in cold weather a bit too long (or something like that, oversimplified anyway), and consequently the engines didn't want to play to the agreed rules on final approach and when the driver put his foot down on final approach the engines didn't respond as commanded. Who remembers the details? Gordon Brown was in the area at the time and there was much spook-related speculation, later ruled irrelevant. It was an RR Trent engine, but lots of them are, there's a lot of them about.
As noted above, you could run a legacy oil-fueled boiler or similar (an Aga?) on this stuff quite easily and quite safely, not to mention large scale industrial steam boilers, process heat, etc. Something like a railway diesel engine might be less sensible - the engine is sensitive to the lubrication and other characteristics of the oil; there are plenty of sad and expensive cases where the wrong oil has been used and bad things happened quite quickly and expensive repairs were then needed.
You *might* even run these fuels in a CCGT power station which typically use de-rated, less critical, versions of aircraft engines. But why would you, if ordinary fuel is cheaper? And anyway, Boeing don't make CCGT power stations, or the engines for them.
Suggesting running a modern ultra-precision-engineered jet engine on this stuff is technically insane. Probably commercially insane too. It's a PR exercise, and nothing more, and not a very good one.
While I'd agree that we should probably be reusing it in more mundane ways, such as cars and electricity generation, I don't think we shouldn't explore other uses, such as aviation. Once the dino-juice is gone, then it'll be back to biplanes and blimps for air travellers, and that I'm sure you'll agree is a sobering prospect. It seems to be for at least two of the worlds largest aircraft manufacturers.
You argue the jets are delicate things, but ice in the filters could happen no matter what the fuel, it's not like they're just going to dump the used oil right into the tanks, scraps* and all!
*colloq. Batter crumbs left over from frying battered fish.
Vegetable oils are a perfectly good substitute for diesel and just need some minor adjustments to the engines. Presumably if you crack the oil correctly you could create the kind of fuel that jet engines need. But, as you say, ordinary fuel is cheaper before tax. If it wasn't there would be a huge displacement of food crops by fuel crops everywhere.
I think it would be possible to used cooking oil - cleaning it is less of a problem than knowing exactly what you've got - but burning it in local power plants is probably the best approach.
"You *might* even run these fuels in a CCGT power station which typically use de-rated, less critical, versions of aircraft engines. "
A few smaller ones do use derated aircraft engines, but most CCGT are actually much larger, slower turning turbines, generating say two or four times the power output of an aviation derived engine. Often made by companies that don't have anything to do with aviation propulsion. If you think about it, there's a need for continuous running for days without attention at the power stations, whereas aviation turbines can be inspected at (almost) every landing if required. There's no weight consideration on a power station, but a need for vast output. And for a power station you want torque on the output shaft, whereas with an aircraft engine you want thrust (yeah, similar but not identical, and with different engineering implications).
A gas turbine wil actually run on just about anything that burns - even coal dust, although as you'd expect the thing wears out in minutes in that case. Natural gas from the mains is ideal because there's few impurities to gunk up the nozzles or blades, the energy input is consistent and easily measured. Aircraft use a form of paraffin (avtur or related terms) because it has the highest practical energy density, and compressed gas would be too heavy. Running a gas turbine off refined cooking oil is the same as running it off diesel - it can be made to work, but it has multiple downsides and few advantages, and you probably wouldn't do it even if the fuel were cheaper than gas.
The other thing about running aircraft on cooking oil (agreeing that it's a rubbish idea) is that the energy density of refined cooking oil is (usually) somewhat lower than diesel. I'd guess you end up with very poor conversion rates for fractionating to an avgas surrogate, and failing that you'd need a lot more fuel to go the same distance.
Ay you say, PR stunt.
"I go through one 46 ounce jar of cooking oil about every 4 years."
OK, so you don't actually cook at home, for the most part (are you serious? You only use an average of about 0.85ish grams of oil per day?). Hopefully you store that oil in the fridge ... Most cooking fats have an un-refrigerated shelf-life of about 3 months, max. Less if it's animal fat, except gawd/ess's gift, Mantica :-)
"What the heck do the Chinese do with 29 million tons a year? Fill their swimming pools with it?"
Do you really not grok how many Chinese folks there are in China? Honestly, the level of comprehension here has been plummeting recently ...
Okay, roughly 1.3 billion people in China = 1,30,000,000
29 million tons = 26 million tonnes = 26,000,000 tons = 26,000,000,000 Kg
So that would be 200 Kg of oil per person per year, so 0.54 Kg per person per day, 540 grams.
Density of cooking oil is about 0.894g/ml.
So that's about 480 ml of cooking oil per person per day, less than a pint. Certainly more oil than I use in a day, but not an impossible amount. Obviously I've made no allowances for wastage.
29 million tonnes appears to be widely quoted as China's edible oils consumption. But that's not the same as per capita consumption, and certainly different to waste oil volumes, which I'd guess to be about half the consumption level. Even then, distributed across China you'd only be able to collect the food service waste, perhaps a fifth of the waste. So that magical 29 million tonnes becomes more like 3 million tonnes. A lot of oil, worth reusing if it economic, but not really going to fuel China's aviation industry.
Two other thingies:
Proper wok cooking (over a 65K BTU+ wok-station) evaporates a good portion of the cooking oil, often over 80% (mine is collected by the ventilation system & recycled as fuel).
Not all "cooking oil" is used for cooking. As an example, "virgin corn oil" (maize oil, to you brits) being used as fuel is causing people to starve to death, world-wide.
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29 M tonnes - that is about 25Kg per person per year. Less than a litre a week. Assume a 70% conversion rate to fuel, and you get about 30 billion litres. China has about 100 million cars, so that is about 300 litres per car per year. Enough to drive each one about 2,500 miles ar 35 mpg That will help the fuel bill.
Even if it does turn out to be technically possible (and it seems to me like the aviation industry is just pushing the dream of abundant supplies of biofuels in order to argue for expansion), aviation would still be an incredibly fuel inefficient form of travel, so you'd still be better off using the fuel in buses, trains, even small cars instead of gas guzzling planes.
"A full 747-400 manages about 90 passenger miles per gallon. I wish my card did that well"
Most full loaded cars will easily beat that. With four passengers it has only to achieve 22.5 mpg to do so. A two seater has to do better than 45 mpg, of course, but that's easily managed by driving carefully. Even at average UK car occupancy (1.4 people), you'd still be doing better than the 747 with the car managing 65 mpg (quite easily achievable in a modern diesel saloon on a longer run - I used to target 90 mpg in the wife's 2001 Skoda Octavia).
Strictly speaking a further adjustment needs to be made for the different energy density of the fuels (diesel has more energy per unit mass than avtur), but ICBA to work that out.
"A full 747-400 manages about 90 passenger miles per gallon. I wish my card did that well"
Most full loaded cars will easily beat that.
Agreed, and that's been an easy goal to achieve for decades, if you routinely put enough people in the vehicle in question. When I were a lad, part of a family of seven, we generally got about in a 1978 Dodge van, with a ridiculously overpowered and inefficient 380 cu in V8 engine (carbureted, of course, with a heavy truck chassis and all the options). But with all seven of us in it - as it usually had - it would still get close to 15 mpg, which is comfortably more than 90 pmpg.
Heck, on the weekend trip I just took with the wife and kid, we averaged either 75 or 100 pmpg, depending on whether prenatal passengers count. (Maybe I should pro-rate based on term?)
This is an interesting answer from a lot of people. Why stop at waste oil though? If you visit Cambridge (UK one that is) there is the museum of technology. Basically this is an old sewage pumping station in the centre of town. Once upon a time this did stirling work shifting crap from the centre of town to the then out of town sewage works (now really in town but there we go). To do this work they took the cities waste and chucked it in damned great fires to create steam to drive the pistons. This had two useful effects, first the sewage could be pumped without the need to import (from elsewhere) expensive fuel like coal, and second getting rid of the waste so you didn't end up with it in a huge pile on the edge of town.
'Progress' and the EU now dictate that we burn Russian gas (bloody expensive) in French/Belgium/occasionally our own power stations and ship the electricity across to power the pumps. Meanwhile we pay tax on the volume of rubbish now carted out of town to be left to rot (and create methane) in huge dumps. Does this seem stupid only to me?
Trouble is that in the intervening century, we've gotten a better grasp of what happens when you burn trash. One of the unfortunate realizations is that there can be some very nasty byproducts. Burn anything subject to bleach, and you can easily end up with a very nasty substance called dioxin: a known airborne carcinogen. Toxic at tiny concentrations (1 part/billion) and known to be the key agent that resulted in two American communities being razed to the ground (Love Canal, NY and Times Beach, MO) and incinerated (you have to burn it at very high temperatures to render it safe). Who knows what else you might unleash if you carelessly burn trash? That's why many communities have burn ordinances.
You're both behind the times. Most landfills in current use now have gas collection fields and use the methane to generate electricity (likewise sewage sludges), and scrubbing dioxins from flue gas isn't a particular problem (although costly if you need to add it after you build your incinerator, and didn't factor the costs in).
Having said that, waste to power is very slowly gaining traction in the UK, but locals are resistant to any form of incineration which makes planning permssion a problem, and the public sector is resistant to new fangled technology such as pyrolysis (not new, proven in Europe).
Interestingly, if you have a pyrolysis plant, then it should change the recycling regime, and that's something else the tree huggers don't like. Everything goes into the pyrolysis plant, except metals (worth recovering), and glass (probably not worth recovering, but equally not worth burning). So all this separation of food waste, plastics, fabrics, paper, plastic etc can stop. And the pyrolysis plant would be quite happy to accept the waste oil that started this thread.
Thing is, pyrolysis is an ENDOthermic reaction, which means you need to feed it energy to keep it going, so it's hard to picture how a process that absorbs energy can then produce energy. Pyrolysis is good for turning waste products into other products you can use like biochar, but what's the ratio of waste in to useable product out? Somehow I suspect it's something greater than 1:1, which will make the tree huggers scream that it's inefficient and that we should still recycle like we did because we get more out of the process.
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