CO2 emissions
 

Anyone care to make a stab at the hourly CO2 emissions of my 150HP Lycoming? Just wondering how many forests I need to plant.

Not a lot.

No Catalyst = bugger all CO2. There will be a lot of Carbon Monoxide, Hydrocarbons, NOx etc, that would have normally been catalysed (if there is such a word) into Carbon Dioxide.

It has occured to me (in the last thirty seconds) that the carbon footprint of GA is actually very small! The detailed research I've carried out in the last five minutes indicates that there is a miniscule amount of CO2 emitted from non catalyst engines. Catalysts make CO2, Engines make VOC's, NOx, CO, water and hydrocarbons, ergo we're low carbon. The harmful effect of these emissions has got to be small considering the amount of flying that takes place so therefore we're green too, and catalysts are bad for the environment.

I thank you.

JC
Petrolhead

Anyone else got anything to add?

Not sure what catalytic converters have to do with it, if only it was that simple.

Mixing units, it's about 10kg of CO2 per imperial gallon of gasoline. Roughly. Planting a tree will only be effective until the tree dies.....

Some one put asked the same question a few weeks ago, ill just say what i said in that post. That the amount of pollution GA make in a year in the UK is about the same cars in the UK make in 8 minutes!!!

If we make a few (wrong!) assumptions:

1. Avgas has a chemical formula of C8H18.
2. It is 100% oxidised to CO2 (clearly not according to the above, but some of the emissions of partial oxidation are greenhouse gases as well, so let's go with this assumption for now).
3. You burn 30 litres / hour.

You will emit 66.7 kg of CO2. Carbon offset companies would charge you about £0.50 to offset that. Whether that actually does any good or not is open to debate - I suspect that there are a few carbon offset companies that have unscrupulous and rich shareholders.

Thanks, Adrian! It's not quite as terrible as I thought.

Carbon offsetting has the feel of a salve for the middle class conscience, but not much more. We shall see...

Ok, humble pie time..

I was wrong - plant them trees! Well maybe just the one anyway.

From the Bosch Automotive Handbook:

"When combustion of pure fuel is complete and ideal, i.e. complete combustion of fuel and oxygen without any unwanted secondary reactions, only the following would be produced:
-Water
-Carbon dioxide"

It's been a few years since I worked on emissions (back when no one really cared!).

Ooops!

JC

QDM,

This is like the film "The Invasion of the Body Snatchers". It seems they have got you too :uhoh:

Adrian,

So burning .72kg of Avgas creates 2.2kg of C02 :eek: I'm really clueless when it comes to this stuff. I must admit I'm a bit stumped. My clueless thinking would be:

If the atomic mass of Carbon is 12 and 16 for Oxygen then for every Carbon atom there would be a bond with two Oxy atoms and so 32/12 = a 2.7 times increase in mass.

So if Avgas is 44% carbon (8/18) and a litre weighed 0.72kg then that would produce 0.32kg of carbon multiplied by 2.7 producing 0.9kg of C02. So 30 litres of fuel would create 27.6kg of C02 :confused: Well it would be less because, I presume, inefficiencies produce other stuff besides like CO and H2O. :confused::confused:

Haulp!

Therein is your error. Gasoline (and I presume similarly, AVGAS) is about 87% Carbon, by mass Most of the rest of the atoms are Hydrogen, which don't weigh nearly as much, despite being more numerous!

0.72kg at 87% = 0.63kg of C, which, multiplying by 44/12, converts to 2.3kg of CO2

Duh! Thanks for taking the time to help Andy.

So, how much C02 does a tree remove per annumn?

Dublin,

http://forestmanagement.enr.gov.nt.c...tree_facts.htm

Thank you HWD

That depends how much it grows. But you should not see trees as being removers of atmospheric CO2.

A tree converts CO2 and water into glucose and oxygen (and water again...). Here's the (simplified) forumula:

6 CO2 + 12 H2O + light → C6H12O6 + 6 O2 + 6 H2O

The glucose is then used to make the various structural bits of the tree, such as cellulose, and it is also used as the tree's source of energy for its cellular respiration. During this latter process it is broken down to form CO2 once again. So, while the tree is alive and growing it absorbs CO2 from the atmosphere. But once it dies, it decomposes and all the organic material (i.e. the molecules that contain carbon) are broken down to produce CO2 and perhaps CH4 (methane, another greenhouse gas). A tree is a temporary store of CO2, but planting trees is not the solution to global warming even if it does help in the short term and can produce beneficial local climate effects such as increased rainfall.

Cut down swathes of forests in their prime and bulldoze them into vast landfills. In 250 million years, global warming will be sorted and there will then be vast swathes of fossilised carbon in holes in the ground and the whole cycle can start again.

Simple.

I also heard that there was a C02 spike during Autumn because of the all the carbon released from the decaying leaves.

But going with the 48lbs per tree per year. A bit of Googling suggests that the UK contains about 2bn trees, enough woodland and forest to 'absorb' 17m cars per year. In more general terms, we need 6bn trees for all transport related emissions and 8bn for all emissions.

Not that I believe the is a GW threat, just in case anybody gets the wrong idea!

Looking at another way... Assume it's octane

C8H18 + 12.5 O2 -> 8 CO2 + 9 H2O

C8H18 has mass 114
8 CO2 has mass 356

So that's 3.1 kg of CO2 per kg of AvGas or 2.3 kg/litre.

We've already established that the chief combustion product is CO2. But just before everyone goes off and tries to make CO by incomplete combustion thinking they're doing the world a favour, just bear in mind that the CO will oxidise to CO2 in the atmosphere over a few months anyway.

Just to keep things in perspective, a fully laden 747 on a 12 hour flight will probably produce about 350 tonnes of CO2. To achieve the same effect in my O-360 engined puddle-jumper, I would need to fly it for around 4200 hours. I just might achieve that much if I continue flying at my current rate until my 70th birthday, but I suspect I will fall short.

(Assumptions for the 747 figure - fuel is uniform C11H24, 12 hour flight, 9400kg / hour in the cruise and an extra 700kg burnt on the ground.)