Industrialized Cyclist Notepad


Butane
October 13, 2013, 22:06
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Blending butane into gasoline is why gas prices fall in the fall, according to Robert Rapier. RVP = Reid vapor pressure, the higher the RVP the faster the evaporation. EPA sets limits on RVP of gasoline which are more stringent in summer months than in winter, allowing the increased blending of cheap, yet highly evaporative (word?) butane:

Butane has an RVP of 52 psi, which means pure butane is a gas at normal pressures and temperatures. But butane can be blended into gasoline, and its fractional contribution to the blend roughly determines its fractional contribution to the overall vapor pressure of the mixture. As long as the vapor pressure of the total blend does not exceed normal atmospheric pressure (again, ~14.7 psi) then butane can exist as a liquid component in a gasoline blend.

But with a vapor pressure as high as 52 psi, butane can’t make a large contribution to summer blends where the vapor pressure limit is 7.8 psi. For example, if a gasoline blend contained 10 percent butane, butane’s contribution to the vapor pressure limit is already 5.2 psi and you would still have 90 percent of the blend to go. It isn’t feasible to blend much butane into gasoline when the vapor pressure requirement is low. But when the limit increases by 5 or 7 psi, it becomes feasible to blend large quantities of butane.

Why do we care about blending butane anyway? Because it is abundant and cheap. Butane can routinely trade at a $1/gallon discount to crude oil or gasoline. Butane is a byproduct of oil refining, but is also a component of natural gas liquids (NGLs), which are condensed out during natural gas production. Given the huge expansion of natural gas production in the US, it should come as no surprise that NGL production is also on the rise.

via Why Gasoline Prices are Falling.



From the Department of Did He Just Say That

“Our people want to know why the flood of new domestic crude oil isn’t lowering prices at the pump,” said Ron Wyden, an Oregon Democrat and chairman of the Senate Energy and Natural Resources Committee. “There is no question that the lower oil costs are not getting through to Americans’ wallets.”

via Senators Grill Refiners Over High Prices Amid Oil Boom – Bloomberg.

If Wyden is this clueless about energy — what “lower oil costs”? — it does not give a fellar confidence that he is an effective guardian of civil liberties (Wyden is on the Senate Intelligence Committee which is supposedly a check on the executive branch’s surveillance fetish). Is he just trying to get someone from the industry to admit the truth, or is he really that out of it.



Gas Prices
April 17, 2013, 22:32
Filed under: Uncategorized | Tags: , , , , ,

The long view.

gaspricesgraph
click to enlarge



EIA price predictions

Always kind of funny. Flat-line forever.

eiagaspricechart



Democrats press O. for SPR release

And that leaves me in weird agreement with Mitch McConnell, one of the most objectionable individuals in the entire den of thieves on Capitol Hill:

“The [SPR] is there for an emergency situation. You have to ask the question: If there were release from the [SPR], would it have the desired effect, and how long would it have the desired effect?” McConnell said.

via Worried Dems pressing Obama on gas prices – TheHill.com.



U.S. average retail gasoline prices

Another look, via Barry Ritholtz’ Big Picture Blog:

http://www.ritholtz.com/blog/2012/02/prices-at-the-pump-on-the-rise/



James Hamilton on crude oil and gas prices

My rule of thumb has been that for every $1 increase in the price of a barrel of crude oil, U.S. consumers are likely to pay 2-1/2 more cents for a gallon of gasoline.

Hamilton points to the lack of adequate pipeline infrastructure in the US to explain the gap between Brent and WTI.

via http://www.econbrowser.com/archives/2012/02/crude_oil_and_g.html




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