![]() | One big sigh... (Sarkozy on lowering gas taxes) | The Oil Drum | Richard Heinberg: Coal in the United States | ![]() |
48 comments on Refining 201: The Assay Essay
Comments can no longer be added to this story.
| Show without comments | PDF version
48 comments on Refining 201: The Assay Essay
Comments can no longer be added to this story.
| Show without comments | PDF version
Search The Oil Drum with Google
Support The Oil Drum
Recently on TOD:World
TOD:Campfire
TOD:Europe
- Peak Gold, Easier to Model than Peak Oil? - Part I
- Carbon Capture and Storage
- Oilwatch Monthly November 2009
TOD:Canada
- In this house, we obey the laws of thermodynamics!
- The Round-Up: October 24, 2008
- Compressed Air Energy Storage - How viable is it?
TOD:Australia/NZ
- International Energy Agency calls 'Peak' on OECD Oil Demand
- Australian Senate: Peak Oil motion defeated 31:6
- The Bullroarer - Friday 20th November 2009
TOD:Net Energy
Blogroll
Energy Sites
- The Coming Global Oil Crisis
- Die Off
- Dry Dipstick
- Energy Bulletin
- From the Wilderness
- Life After the Oil Crash
- Peak Oil Crisis
- Peak Oil News and Message Boards
- Powerswitch
- Rigzone
- Matthew Simmons
- Wolf at the Door
Environment & Sustainability Sites
- The Daily Green
- EcoGeek
- Eco Street
- Green Car Congress
- Green Options
- green.alltop.com
- Gristmill
- RealClimate
- Sustainablog
- Treehugger
- WorldChanging
Blogs
- Casaubon's Book
- Cleantech Blog
- Clusterf
k Nation (Jim Kunstler) - The Cost of Energy
- David Strahan
- Early Warning
- The Energy Blog
- European Tribune
- GraphOilology
- Health After Oil
- jeffvail.net
- Mobjectivist
- Peak Energy (Australia)
- Peak Energy (USA)
- R-Squared
- Resource Insights
Finance & Economics Blogs
- The Big Picture
- Calculated Risk
- The Crash Course
- Ecological Economics
- Econbrowser
- Environmental Economics
- Infectious Greed
- The Mess That Greenspan Made
- Mish's Global Economic Trend Analysis
Organizations
Peak Oil Primers
Beware email scams!
Beware email scams claiming to be from this site. We do not have any job openings. If anyone contacts you about a job at The Oil Drum, do not reply to them, and definitely do not give them any personal information or send them money. Read more here.
“We have only two modes—complacency and panic.”
—James R. Schlesinger, the first energy secretary, in 1977, on the country's approach to energy
User login
Contact
- Content: editors at theoildrum dot com
- Tech support: support at theoildrum dot com
Personnel
- Editors: Nate Hagens, Gail the Actuary, Prof. Goose
- DrumBeat Editor: Leanan
- Contributors: ace, Engineer-Poet, Heading Out, jeffvail, JoulesBurn, Sam Foucher, Robert Rapier
- TOD:Campfire: Glenn, Jason Bradford
- TOD:Europe: Chris Vernon, Euan Mearns, Francois Cellier, Jerome a Paris, Luís de Sousa, Rembrandt, Rune Likvern, Ugo Bardi
- TOD:Canada: benk, Libelle
- TOD:ANZ: Big Gav, Phil Hart, aeldric
- Emeritus: Stuart Staniford
- Technician: Super G
License
This work is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.










GAIA Host Collective
Thanks for the great explanation. I have tried in my own inept way to differentiate between Light Sweet and Heavy Sour grades for friends and family, and get met with blank stares. I will get them to read your version.
I do have a couple of questions.
Crude gatherers, in Oklahoma and Texas at least, buy different grades and blend them to 40 gravity, or more specifically in the 36.5 to 40.5 gravity, to minimize the penalty when they do a pipeline tender. In effect, they are blending condensate (for the most part) and heavy crude. Have you ever had any experience with this at the refining end, and what does this do to the refining process and to the assay? Is this specific to the final blended crude or is there a general result of about the same as the sample assay you show for Light Sweet?
As we import more finished product, would you anticipate asphalt becoming proportionately more expensive than other refinery products, or has this already happened?
Chuck
Have you ever had any experience with this at the refining end, and what does this do to the refining process and to the assay? Is this specific to the final blended crude or is there a general result of about the same as the sample assay you show for Light Sweet?
Two comments on this one. Yes, I have experience with some Canadian blends that they mix together from several fields to meet a gravity spec. The good thing about that is that you get a pretty consistent crude. This is one thing that makes operating a refinery more difficult - when you crude quality is swinging.
But, there are multiple ways to get to a certain gravity, as you indicate. And I have seen some of those middle cuts essentially missing. In that case, you know they did something like mix up condensate with very heavy stuff.
As we import more finished product, would you anticipate asphalt becoming proportionately more expensive than other refinery products, or has this already happened?
I don't know if it has been rising at the same rate, but asphalt prices have run up with crude oil. But what makes asphalt at risk of rising disproportionately is the fact that refiners are installing cokers, and taking asphalt off the market and turning it into gasoline.