Natural Oil Polythiols and Polyols– A Life Cycle Comparison Thomas A. Upshaw, William J. Fisher, Eric J. Netemeyer Chev

1. Natural Oil Polythiols and Polyols– A Life Cycle Comparison Thomas A. Upshaw, William J. Fisher, Eric J. Netemeyer Chevron Phillips Chemical Co., LP ACS Green Chemistry & Engineering Conference June 25, 2008 ACS Green Chemistry and Engineering Conference 2008

2. Outline • Study objectives • Modeling tools and information sources • Modeled systems and assumptions • Mercaptanized soybean oil (MSO) • Petrochemical (flexible polyether) polyol • Castor oil • Soy-based polyol • LCA Methodology • Impact category results • Conclusions ACS Green Chemistry and Engineering Conference 2008

3. Soy Polythiol – MSO (Polymercaptan 358) ACS Green Chemistry and Engineering Conference 2008

4. Objectives • Develop a soy polythiol life cycle inventory (LCI) platform for product life cycle assessment through the product manufacturing stage (cradle-to-customer) • Compare life cycle environmental impacts using updated LCI data for vegetable oil and petrochemical (polyether) polyols to quantify the benefit of using a renewable oil as raw material • Future: assess process changes and new process technology for reduced environmental impact ACS Green Chemistry and Engineering Conference 2008

5. Life Cycle Modeling Tools • SimaPro 7.0 software, using SimaPro 7.0 database and U.S. LCI database • BEES (Building for Environmental and Economic Sustainability) impact model • NIST sponsored & EPA supported • Methodology used by USDA BioPreferred program • Conducted in accordance with ISO 14040:1997(E) standard • TRACI (Tool for the Reduction and Assessment of Chemical and other Environmental Impacts) – EPA life cycle impact assessment method ACS Green Chemistry and Engineering Conference 2008

6. Data Sources • Soybean data • Agriculture data from U.S. LCI database (NREL) • Processing data from NREL LCA report on biodiesel 1998 • Soy Polythiol – Chevron Phillips Chemical Co. • Process inputs estimated from commercial production facility, assuming conventional H2S process technology • Soy-based Polyol • 2004 manufacturer-specific BEES input streams • Petroleum (flexible polyether) polyol • U.S. LCI database • Castor oil • Purdue University article and various internet sources • Incomplete process data supplemented by analogous data on other seed oils in U.S. LCI database ACS Green Chemistry and Engineering Conference 2008

7. LCA System Boundaries LCI INPUTS LCI OUTPUTS Upstream Production of Raw Materials Crop oil Feedstocks Petroleum Feedstocks Agricultural production Process energy Raw materials production Air emissions Water effluents Materials production, transport Vegetable oil production & refining Waste Process energy Product Polyol or Polythiol Manufacturing Stage Air emissions Water effluents Materials production, transport Waste Transportation to the customer Energy, materials Air emissions ACS Green Chemistry and Engineering Conference 2008

8. MSO Polythiol Assumptions • Commercial process design based on known reaction conditions from trial runs at Philtex plant (Borger TX): • UV reactor • Estimated stoichiometric excess of H2S • Stripping and recycle of H2S • Known reaction conditions from lab/pilot work • Conventional energy sources (nat. gas) ACS Green Chemistry and Engineering Conference 2008

9. Petrochemical Polyol Assumptions • Consolidated proprietary information for 5 North American plants, 2003-5 data • Polyether polyol, glycerin-initiated, 3500 mol wt (on average) • KOH-catalyzed, solvent, water-washed • 7.6 to 1 wt ratio PO/EO ACS Green Chemistry and Engineering Conference 2008

10. Castor Oil Assumptions • Complete data were not available • Significant uncertainty, need better data • Analogous LCI data for other seed oils were used for some LCI inputs (fertilizer usage, energy) • Since growth and modernization of castor agriculture has been occurring, mechanized production and irrigation were assumed for 75% of production • 8200 mile transport from India to U.S. market assumed before distribution in the U.S. ACS Green Chemistry and Engineering Conference 2008

11. Soybean Oil Polyol Assumptions • 2004 manufacturer-specific BEES data • Produced by simple air oxidation of soybean oil • No further refinement, purification or derivatization • Soy agricultural model • Not sure if waste/off-grade is taken into account • 1000 mile transport to customer This probably represents the most environmentally benign vegetable oil polyol process possible; a benchmark for comparison of other renewable products ACS Green Chemistry and Engineering Conference 2008

12. LCA Methodology • Life Cycle Inventory – quantified listing of inflows and outflows per 1000 lbs of product (built in SimaPro 7.0) • Converted to equivalent units per 1000 lbs and combined into LCIA impact categories (BEES impact model) • Normalized to unitless dimensions corresponding to fraction of total U.S. impact per year per capita • Overall BEES environmental score: sum of normalized impacts weighted by importance • 2006 BEES Stakeholder Panel ACS Green Chemistry and Engineering Conference 2008

13. LCA Methodology • Life Cycle Inventory – quantified listing of inflows and outflows per 1000 lbs of product (built in SimaPro 7.0) • Converted to equivalent units per 1000 lbs and combined into LCIA impact categories (BEES) • Normalized to unitless dimensions corresponding to fraction of total U.S. impact per year per capita • Overall BEES environmental score: sum of normalized impacts weighted by importance • 2006 BEES Stakeholder Panel ACS Green Chemistry and Engineering Conference 2008

14. Impact Comparison (Cradle-to-customer) ACS Green Chemistry and Engineering Conference 2008

15. ACS Green Chemistry and Engineering Conference 2008

16. ACS Green Chemistry and Engineering Conference 2008

17. ACS Green Chemistry and Engineering Conference 2008

18. ACS Green Chemistry and Engineering Conference 2008

19. Conclusions • LCA is a valuable tool to help assess environmental impact of products and processes at a more detailed level. • more standards and complete, up-to-date publicly available data are needed to improve general utility and consistency. • Global warming potential and fossil fuel use of MSO and vegetable oil polyols are significantly lower than for the petroleum-based polyether polyol due to the crop oil raw material source. • Agricultural practices, oil extraction methods and shipping also have a significant impact. • Future use of renewable energy for MSO production would result in a significant reduction in global warming potential (GWP) and fossil fuel consumption. ACS Green Chemistry and Engineering Conference 2008

20. Conclusions • Next generation process technology currently under development may significantly reduce energy consumption, GWP and SOx generation (i.e., criteria air pollutant and acidification impacts). • Castor oil was comparable to MSO overall (BEES), but better life cycle input data for castor oil is needed • Castor suffered from the use of the solvent extraction process and (probably high) estimated water and fertilizer use (vs MSO) and eutrophication and smog potential were high vs soybean oil polyol. • A best case soy oil based polyol showed less than 16% the overall impact relative to a petroleum-based polyol • But: best case (simple) process does not necessarily give a product with acceptable end-use properties ACS Green Chemistry and Engineering Conference 2008

21. Acknowledgements • American Chemical Society • Jim Pollack, OmniTech International Ltd. • Anne Landfield Greig, Four Elements Consulting, LLC • Chevron Phillips Chemical Company, LP ACS Green Chemistry and Engineering Conference 2008