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A Technoeconomic and Environmental Life Cycle Comparison of Green Diesel to Biodiesel and Syndiesel
Tom N. Kalnes,a Ken P. Koers,b Terry Marker,a and David R. Shonnardb a UOP LLC, A Honeywell Company, Des Plaines, IL b Department of Chemical Engineering, Michigan Technological University, Houghton, MI; drshonna@mtu.edu (for correspondence)
Published online 20 March 2009 in Wiley InterScience(www.interscience.wiley.com). DOI 10.1002/ep.10319

Green diesel, a renewable diesel fuel produced via the UOP/Eni EcofiningTM process, has the same fuel quality attributes as syndiesel but, over its life cycle, consumes less fossil fuel and generates less greenhouse gas emissions than petroleum diesel. From an investment standpoint, the production of green diesel is competitive with biodiesel.Moderately sized units consistent with current large-scale biodiesel production can be economical, especially when integrated into an existing petroleum refinery. Ó 2009 American
Institute of Chemical Engineers Environ Prog, 28: 111–120, 2009

Keywords: LCA, biodiesel, green diesel, syndiesel

INTRODUCTION

Over the past decade, the production of biodiesel from plant oils such as soybean (SBO),rapeseed (RSO), and palm oils has experienced rapid growth and increased international market demand. Projected future shortages of crude oil coupled with the growing worldwide demand for transportation fuels has also piqued interest in synthetic diesels (syndiesels) produced by Fischer Tropsch (FT) synthesis of a syngas stream derived from either coal (coal-to-liquid), stranded natural gas (NG;gas-to-liquid, GTL), or biomass (biomass-to-liquid, BTL).
Ó 2009 American Institute of Chemical Engineers

Green diesel is a renewable diesel fuel produced via the UOP/Eni EcofiningTM process. Similar to FT diesel, green diesel is a paraffin-rich, fully deoxygenated alternative diesel fuel that burns very cleanly. Similar to biodiesel, green diesel is produced directly from natural oils and fatsand, as such, provides significant benefit as an alternate fuel with respect to greenhouse gas (GHG) emission reduction. The goal of this article is to briefly introduce the Ecofining process and highlight the advantages and limitations of green diesel relative to petroleum diesel, biodiesel, and syndiesel. The processing steps, product quality, and life cycle assessment (LCA) for each alternativefuel are compared with conventional petroleum diesel. The LCAs reported here have been conducted using several different method assumptions and with data from different geographic regions in order to make the comparison to green diesel more comprehensive. Although many different study assumptions are included, the effects of land use change are still being investigated and are not included in thispublication. The economics of producing green diesel are also discussed.
BACKGROUND

To date, most new capacity for producing diesel fuel substitutes from triglyceride-rich plant oils has centered on transesterification with methanol to produce fatty acid methyl esters (FAME), referred to as biodiesel. While environmental benefits have been
April 2009 111

Environmental Progress & SustainableEnergy (Vol.28, No.1) DOI 10.1002/ep

demonstrated for biodiesel relative to petroleum diesel [1–3], there are some fuel quality limitations with biodiesel that may ultimately limit future growth. These limitations include fuel storage stability, cold flow properties in winter climates, and excessive solvency that can lead to engine compatibility issues. Syndiesel is a clean fuel having highenergy content (44 MJ/kg) and very low combustion emissions [4, 5]. Although FT is an established technology that has already been applied on a large scale, its growth has been hampered by the uncertain and volatile price of crude oil. Also, the use of NG as a feedstock (GTL) competes with the direct sale of NG to consumers, which, depending upon well location and pipeline availability, can be more...