The document summarizes a study on the implications of higher level ethanol blends on greenhouse gas emissions from petroleum refineries. The study found that increasing ethanol content in gasoline resulted in significantly lower greenhouse gas emissions from refining operations, due to decreases in crude oil processing and more efficient refinery unit operations. However, the study noted greenhouse gas emissions from refineries vary depending on the ethanol content and octane specifications of gasoline, and these factors should be considered in lifecycle analyses of higher ethanol blends. Changes in refinery operations from increased ethanol use could also impact other environmental regulations.

1. Stationary Source GHG Emissions from
Petroleum Refinery Operations:
Implications for Higher Level Ethanol Blends
February 17, 2016
National Ethanol Conference
New Orleans, LA
Dr. Vincent Kwasniewski
President
Confluence Consulting LLC

2. Objective
2
Moving to higher level ethanol blends: what would be the
impact on stationary source emissions of greenhouse gases
from oil refineries?

3. The Broader Context
3Data Source: M. Wang, et. al. (2014)
12% of the
GHG emissions
“LCA Stack”
-13
4
31
4
14
10
9
Bio-refining
Transportation
Combustion
Farming
Fertilizer N2O
Fertilizer
Production
Land Use
Change
60 gCO2eq/MJ
73.3
11.2
5.5
Combustion
Refining
Crude Recovery
Transportation
93 gCO2eq/MJ
Refinery BOB
Fuel Ethanol
(from corn starch)
N
E
T

4. Natural Gas
& Utilities
Reformer
Isomerizatio
n Unit
Alkylation
Unit
BOB
Blending
Catalytic
Cracking Unit
Model PADD 2 Refinery
4
D
I
S
T
I
L
L
A
T
I
O
N
Crude
Distillate
Hydrotreater
Gas Oil
Hydrotreater
Coker
Naphtha
Hydrotreater
Distillate
Blending
Other
Products

5. Petroleum Refinery Planning
5
Profit
Variable B
Variable A
Optimum
• “Linear Programming” (LP) tools & methodology
• Many physical, market, & regulatory constraints
Optimum
constrained by A
Min A
Constraint
Optimum
constrained
by A & B
Min B
Constraint

6. Refinery BOB versus Fuel Ethanol
6
Ethanol:
• Single component
• Fixed blending properties
Refinery BOB:
• Many components
• Many refinery streams
• Variable blending properties
which vary with refinery,
season, and market factors
Composition by component
Fuel Ethanol Refinery A Summer Refinery B Winter
Broad
Distribution
of Hydro-
carbons
Broad
Distribution
of Hydro-
carbons

7. Gasoline Blending
7
Refinery
BOB
Ethanol
Refinery
Stream A
Refinery
Stream B
Purchases

8. Refinery Emissions Study Methodology
• Hypothetical end state where all gasoline contains high levels of
ethanol – no transition analysis:
8
 E10 base case plus
eight “corners” of an
octane × ethanol
content × gasoline pool
volume space
 Survey study only -
ethanol blend levels
and the minimum
octane specifications
are not to be taken as
recommended values
Ethanol Content
Octane
Rating
Gasoline
Pool
E20
88 AKI
Equal Volume
E30
97 AKI
Equal Energy
Base Case
E10
88 AKI
• 2011 Energy Information Agency projections for 2017 with Oil
& Gas Journal published unit capacities
• Modeled with detailed PADD 2 refinery
operational planning tools and
methodology from Jacobs Consultancy

9. Refinery Unit Operations Results
• Cat cracker
throughput 
(make less gasoline)
• Reformer
throughput 
(make less octane)
9
Max octane:
Current octane:
• Cat cracker
throughput ,
but less so
(make less gasoline)
• Reformer
throughput 
(make more octane)

10. Gasoline Blending Results
Low octane requirements  Reformate  / naphtha 
High octane requirements  Reformate  / naphtha  10

11. Refinery Greenhouse Gas Emissions
Increased levels of ethanol in finished gasoline resulted
in significantly lower GHG emissions in refining
11

12. Refinery Greenhouse Gas Emissions
12
Decreased GHG emissions in refining due to both extensive
effects (lower crude run) AND intensive effects (lower
emissions per barrel of crude)

13. Conclusions and Implications
• GHG emissions caused by the refining process vary
significantly with ethanol content and minimum octane
specifications in finished gasoline
• Using a fixed GHG emissions intensity for BOB is
incorrect  ethanol content and minimum octane
specifications should also be factors in determining the
lifecycle GHG emissions associated with higher level
blends of ethanol
• Changes in refinery operations could also have
implications for other environmental policies:
• CAFE standards compliance
• Tier 3 compliance (sulfur)
• regulation of stationary source and vehicular toxic air emissions
• possible future stationary source GHG emissions regulations
13

14. Thank You!
Key references on refinery greenhouse gas emissions:
• Kwasniewski, V., Blieszner, J. and Nelson, R. (2015), Petroleum refinery
greenhouse gas emission variations related to higher ethanol blends at
different gasoline octane rating and pool volume levels. Biofuels, Bioprod.
Bioref.. doi: 10.1002/bbb.1612
• Han, Jeongwoo, Elgowainy, Amgad, Michael Wang and Vincent Divita (2015),
Well-to-Wheels Greenhouse Gas Emissions Analysis of High-Octane Fuels
with Various Market Shares and Ethanol Blend Levels. United States.
doi:10.2172/1212715. http://www.osti.gov/scitech/servlets/purl/1212715
• Hirshfeld, D.S., Kobl, J.A., Anderson, J.E., Studzinski, W. and Frusti, J.
(2014), Refining Economics of U.S. Gasoline: Octane Ratings and Ethanol
Content. Environmental Science & Technology 48, 11064-11071. doi:
10.1021/es5021668
• Speth, R.L., Chow, E.W., Malina, R., Barrett, S.R.H., Heywood, J.B., Green,
W.H. (2014), Economic and Environmental Benefits of Higher-Octane
Gasoline. Environmental Science & Technology 48, 6561-6568. doi:
10.1021/es405557p
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