Sue's The Road Warrior Review

[duckie]

Well, time for me to chime in.

Now we know from the little kid in Jerry Maguire that the human head weighs 8 pounds. If, for simplicity sake, we were to assume that the majority of that mass was brain matter, and that it had a density of 1.8 kg/liter, that would mean that the most the brain could be is 10 liters, or approximately 2.5 gallons.

If we then assume that the calorific value of the brain matter is approximately equal to that of most hydrocarbons (which is probably an overestimate, given the fact that we all know that one can have water on the brain, thereby reducing the energy content), we can assume that you could travel approximately the same distance as 2.5 gal of gasoline (or petrol, depending upon where you're at).

So, on a good day, you'll need to consume one hitchhiker's brain every 40 miles or so, in order to keep your SUV running.

Now, there's probably a research project in there somewhere... I'd be looking for funding, to determine if a higher IQ is due to increased brain matter density and, if so, whether that would lead to an improved fuel economy for your vehicle.

[Lissa]

Is that assumption valid though? (I did mine by guessing at the volume of a brain.) The kid's head is eight pounds, sure, but a lot of that is bone and as you said water (which must be removed or it will greatly inhibit the transesterification process). Although I agree that IQ and brain size should be investigaged. Rich with his IQ of 150 might make more fuel from his brain than mere mortals.

Excuse us. Duckie is reading this response over my shoulder and we're having a debate as to whether the transesterification process is necessary (that's when you react it with alcohol). I say it is because it increases the energy you can get out of the brain fuel, and you can use your brains in colder temperatures. And yes, the hydrocarbons in fat have a lower energy content than the hydrocarbons in petroleum diesel.

Duckie declines to comment at this point. I think it's cause he needs time to refute my excellent point.

The other issue is these veggie cars you hear about where people dump fat/used cooking oil into the engine require a kit to facilitate the process. If you react your brain with alcohol, then you don't need this additional kit- you can just put it right into your fuel tank. Transesterification is the way to go. (And not just because that's what I research for a living, thanks.)

Anyone know the weight of a brain, and what percentage of that is water?

[pfrsue]

So setting aside the transmogrification, transvestrification or whatever the word is, are you suggesting that the savvy commuter would be well advised to pick up alcoholic hitchikers? Particularly the variety that are already half in the bag? Would that then translate to better mileage? Say... fifty miles per brain instead of forty?

And are these highway miles or city miles?

[Hucklebubba]

Lissa said:

the brain is mostly fat,

Everytime I'm reminded of this, I get depressed. It's just such a bummer to think that the purest physical representation of "being"--the seat of the soul, if you will--is primarily composed of one of the most reviled substances in existence. In the European fashion circuit, leastwise.

Say, since the rest of my body is also mostly fat, shouldn't I be able to use pyrokinesis, or something?

duckie said:

So, on a good day, you'll need to consume one hitchhiker's brain every 40 miles or so, in order to keep your SUV running.

If there's somebody out there foolish enough to make a sequel to Maximum Overdrive, I dearly hope they read this thread first.

[bladestarr]

*reads the ongoing discussion of using brains for gas*

I love you guys. *tear rolls down a cheek* ;D

[DocD83]

Now we know from the little kid in Jerry Maguire that the human head weighs 8 pounds. If, for simplicity sake, we were to assume that the majority of that mass was brain matter, and that it had a density of 1.8 kg/liter, that would mean that the most the brain could be is 10 liters, or approximately 2.5 gallons.

Either your conversion or your assumption is off here, because my head could almost fit into a gallon jug. If you removed the nose, lower jaw, all the vertabrae, and hair (I desperately need a haircut).

[pfrsue]

You know how they say you are what you eat?
This does answer the fat content question though.

www.kellydorfman.com/pages/459019/

[Magill]

Sue--I saw some program talking about gasoline pipelines and how gas is shipped around the country through them. They said that there really wasn't a lot of separation of the different brands/octanes, and that all gas is pretty much the same until the sellers add additives. So, are polynuclear aromatics a normal additive that Amoco gold doesn't contain, or am I just being too cynical?

Now, on to the brain stuff.

From here I find that the average mass of a human brain is 1500 grams.

This says the human brain is 70% fat. I'll assume that's by mass. I am a bit nervous, because that seems like a sketchy site.

Thus, the average person has 1050 g of fat in their brain.

Instead of assuming the energy in the fat is equivalent to that of hydrocarbons, I'll use the nutritional label shortcut and proclaim 1 gram of brain fat provides 9 Calories (which we all know is really 9 kcal) of energy.

Thus, the fat in a brain could provide 9450 kcal of energy. Now's the time for you fuel scientists to tell me how many gallons of gas that's equivalent to.

[pfrsue]

Okay, so I actually did some research, based on Magill and Lissa's comments and I found out that.....
Amoco Ultimate does contain very low amounts of PNA's.

www.bpdirect.com/pdfs/Crystal_Clear_Amoco_Ultimate_Gasoline.pdf

Very low though, since the Amoco premium is a clear color as oppsed to the standard yellowish hue. (And no brains in it. I double checked.)

Anyway, see? I can admit when I'm wrong.
But to think I trusted that lecturer! He was so perky and enthusiastic and... and convincing in his BP shirt and neatly pressed dockers!

[Magill]

So gasoline really is yellowish? I saw Zoolander this weekend, and during the gas fight scene I was surprised that it was yellow.

I feel really dumb. Buy hey, as far as I know, the gas goes from a buried tank, through and opaque hose, and into my gas tank. I guess I've really never seena large batch in a clear container.

[duckie]

I can see this as a word problem: "Little Jimmy wants to head from New York City to Alburquerque, but only has enough money for food. If we assume that he can realize all the energy potential locked up in the human brain as transport fuel, how many drunken hitchhikers will he need to pick up as he heads westward, in order to keep his vehicle running?"

We're morbid

Anyway, I did a little bit of additional research as well (the web is an amazing thing!). The numbers that Magill was quoting for brain size and fat content are similar to those I was able to find from legitimate sources (i.e., medical journal articles, located online). And, so if you approach this by looking at the calorific value of the fat content, this compares to the energy content of ~1L of gasoline. So, you might only be able to travel 4 or 5 miles on a single brain's energy.

Oh, and DocD83, I guess my assumptions were a little bit off - the average human brain must be more dense than I originally thought. ;D

I will say that I can't fit my head into a gallon milkjug... but then again, I've been told many times that I've got a big head

[duckie]

Magill said:

Sue--I saw some program talking about gasoline pipelines and how gas is shipped around the country through them. They said that there really wasn't a lot of separation of the different brands/octanes, and that all gas is pretty much the same until the sellers add additives. So, are polynuclear aromatics a normal additive that Amoco gold doesn't contain, or am I just being too cynical?

This reminds me of the Simpson's episode, where they showed all the types of Duff beer, coming from one central vat.



In terms of the fuel difference - Here's a fairly non-technical article that outlines the distribution system. Essentially, my understanding is that there are some differences between the base fuels, due to the refinery processes. But, once it gets to the terminal, that's when the additive packages are included, and the fuels really become unique.

BTW, PNA's are in the base fuel due to the crude oil that was used. Different degrees of processing (e.g., distallation, hydrotreatment, etc) will remove them, to different degrees. A highly-refined base fuel (such as Amoco's ultra) might be low in PNA, due to the effort at the refinery.

I don't work in the oil industry, so this is based upon what I've learned during my last trip through school. But, Lissa would probably have a more definitive answer; after all, she taught a number of Petroleum Processing classes in grad school...

[Lissa]

Petroleum Processing 101, as taught by Lissa

Gasoline does have a yellowish tinge to it, as does diesel (although diesel is a darker yellow). (If you have red diesel, it's been dyed. And it's dyed because it's acceptable for certain uses, but not all uses.)

What happens is them refinery recieves crude oil. You know how you can draw a molecular structure for water or salt? Well, you can't do that for oil. Oil is made up of literally thousands of different compounds, from methane to those polynuclear aromatics Sue was talking about. The percentage of these compounds is also not the same from oil to oil. The compounds are broken down into four classes: alkanes (carbons strung together, sort of like beads on a wire), napthenes (carbons strung into rings, sort of like lace), aromatics (carbons strung into rings like napthenes, but instead of one bond between each carbon, ever other bond is a double bond), and heteroatomic compounds (compounds that have other atoms besides hydrogen and carbon in them). Depending on what sort of plant/animal life the oil was formed from, the conditions of formation, and how old the oil is, the proportions of these compounds vary. Some oils have a lot of alkanes (this is good), and some have a very high percentage of aromatics (this is bad).

So the crude gets to the refinery, and enters the distillation tower. Remember how I said there are thousands of compounds in oil? Well, each of those compounds has a different boiling point. The refineries use the boiling points to distill off different fractions. Now, obviously they're not going to distill each and every compund individually. What they do is break the crude down into different fractions based on a range of boiling points. Components in gasoline, for instance, starts boiling at... oh shoot... maybe 25 degrees C? As you increase the temperature more and more compounds are boiled off, and the last ones come off around 150 C. The next set of compounds are what go into kerosene, and the next diesel, then fuel oil, etc. (precise boiling ranges to be inserted tomorrow- if I remember.)

Some polynuclear aromatics have boiling points in the right range for gasoline, which is how they get in there.

Anyway, the amount of gasoline you can get by just distilling the fuel isn't enough here in America. So you need to wring gasoline from other, less profitable streams in your refinery. So you make it, and a lot of times when you make it, you end up with the more aromatic compounds. However, you still separate out appopriate compounds by distillation.

The other problem with "straight run" (just distilled) gasoline is that it doesn't always have a high enough octane rating for engines. We used to put tetraethyl lead into gasoline to increase the octane rating. However, pollution became a problem, and the catalytic converter was added to cars. Lead will cling to the catalyst, making your catalytic converter useless and your car will pollute more. So lead was removed from gasoline.

But how to get the octane rating up without lead? Hey, did you know that benzene- a single ring of six carbons with alternating double bonds- has an octane number of 100?

Aromatics really increase the octane rating of gasoline. PLUS, when you try to make aromatics, you also produce hydrogen. Why is that important? Well, you use hydrogen to get rid of those nasty heteroatomic compounds that I mentioned early on and seemed to forget about. So it seems like a win-win situation.

The problem is twofold. One: aromatics are carcinogens. (That's bad.) Two: soot is a conglomeration of aromatic compounds. That's REALLY bad. You can still make soot from a fuel that doesn't have aromatics in it, but first you have to make those straight chains of carbons into rings, and then you have to remove hydrogens to make double bonds. But if you start with aromatics already, it's much easier to make soot. All gasolines have some aromatics: polynuclear aromatics mean you have more than one ring fused together.

Not such a big deal in gasoline engines, to be truthful, because they have good pollutions technology to deal with it. But it's a huge deal in diesel engines.

Anyway the moral of the story is that Amoco has polynuclear aromatics in their gasoline because they fall into that boiling range and aromatics raise the octane number.

Oh yeah! The other thing I was getting at:

I'm not too clear on distribution. But I do remember touring Sunoco's Marcus Hook refinery and seeing the where they transported JP-8, the military jet fuel. The kerosene came down to the ship that it was being transported in, and then at the last minute the (extremely stinky) additive package was added- before the fuel left the refinery.

So to summarize: oil companies drill oil, and send it to their refineries or sell it to refineries. Refineries break the crude oil down, make their fuels, add additives at the appropriate time, and then ship them off to fueling stations (or the other way around). At least, that's my understanding.

And I'm not positive why it's yellow. It may be due to the presence of heteroatomic compounds, but also may be due to additives that they put in.

Thus concludes petroleum processing 101. WAKE UP!

[bladestarr]

So maybe you oil geniuses can explain this to me. What is ethanol, what does it do and why is the ethanol gas the cheapest around here instead of plain old Regular? You'd think that a fuel with an additive would be MORE expensive than one without it.

[pfrsue]

I'm no genius and this is mostly a guess, but ethanol does have a corn base. So I would imagine that because ethanol isn't imported and because the government probably does some subsidizing in its production and distribution, it's a little cheaper than normal gasoline. (In this area, it's not much cheaper - a matter of only one or two cents - but my state has one of the highest gas taxes in the nation.)

However, if I remember right, ethanol can be a little more caustic on some engine componants over time.

I'll leave it to the real experts to confirm this... or otherwise.