Wednesday, October 31, 2012

Anthropogenic Global Warming - Part 3 - Oil Refining and Combustion


Chipmunk gnawing on nut
I'm currently working on building an argument supporting Anthropogenic Global Warming, one chunk at a time.

Previous Parts:

Today's part is about how humans pull the hydrocarbons out of the ground and refine it and burn it.

Personal Commentary

I'm going through this somewhat pain-stakingly, but I'm trying to make sure my argument is solidly backed up by citation and fact. I actually didn't know the process behind photosynthesis and plant growth. All I knew was that there was something about plants pulling CO2 out of the air. I was curious to know how this worked, and even if it worked. It's been nice to actually learn this stuff.

Argument so far

Plants pull CO2 out of the atmosphere to build plant matter. 

Plant matter can die, be buried, and through a process called thermochemical conversion, turn into hydrocarbons, whether it's a liquid crude oil, natural gas or coal. This has been happening for at least 475 million years, with the amount of CO2 stored in the ground accumulating during that time.

Knowledge

Focusing more specifically on crude oil, the substance we pull from the ground is not initially ready for use. Crude oil can range from 50% to 95% hydrocarbon by weight, as a mixture of different types. A distillation  process is used to separate the different types of hydrocarbons. [1] From each barrel of crude oil, the typical U.S. refinery produces 50% gasoline, 40% diesel, heating oil, kerosene and jet fuel, and 10% residual oil. [2]

The combustion process releases CO2, among other molecules, with either complete or incomplete combustion. [3] We can measure the chemical output of vehicles, and have done many studies on the effects of temperature and equipment on the car emissions. For instance, a standard vehicle (year 2000) at 20F can emit anywhere from 20 to 60 grams per mile, depending on speed (estimates from MOBILE5a, fleet average, low altitude). [4]

How this ties into the argument

I first wanted to make sure that oil refineries weren't doing something magical like removing the CO2 from the chemistry. It's a straight forward question - what does "refining" the oil mean? So that's answered.

Secondly, I wanted to get some kind of grounding in the idea that we know what the chemical reactions were that produce CO2, and more importantly, that we can measure them coming out of vehicles.

This is all basically establishing that I'm not just delusional about the idea that humanity is pumping CO2 into the atmosphere by burning fossil fuels.

I probably could have just skipped past this point, and to the agreement that we're doing that. I don't think anyone denies that fact. It's the results that are in dispute. Still, I want to make sure I'm grounded in fact.

Woah

I came across a diagram that caught me off guard. The chart was titled something to the effect of "quadrillions of BTUs released". It hadn't dawned on me before that the actual heat released by combustion might play a role. I was focused on the long term problem of a greenhouse gas buildup.

After all, we don't burn heating oil up here in Maine merely to convert one set of chemicals into another. We do it for heat. That heat eventually dissipates into the surrounding environment - as would the heat from all things burned ever.

Honestly, that brings up an important question. How much of that heat is directly contributing to the increase in temperature globally? Is it just a small fraction? Is it 100%? I don't know.

This can be a potential problem when making the case that greenhouse gases are increasing the temperature. I'm going to have to see if I can figure out how many BTUs we've released - at least a conservative estimate. Then, I'll need to figure out how many BTUs are required for the corresponding temperature increase. Maybe then I'll be able to establish some difference between the two.

Of course, the net temperature of the planet is the combination of many factors, from geological activity within the Earth, solar radiation being adsorbed (into the oceans, or goth kids wearing their goth clothing outside), solar radiation being retained through the greenhouse effect (which really accounts for most of the persistence of temperature in the first place), etc.

This may get complicated. I'm trying not to just have the answers handed to me. I'm trying to figure them out.

This is technically all for a video, but I may have to switch to some other video topic for this next month while I continue to research.

Works Cited

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