Analyzing the energy intensity and greenhouse gas emission of Canadian oil sands crude upgrading through process modeling and simulation

Abstract

This paper presents an evaluation of the energy intensity and related greenhouse gas/CO₂ emissions of integrated oil sands crude upgrading processes. Two major oil sands crude upgrading schemes currently used in Canadian oil sands operations were investigated: coking-based and hydroconversion-based. The analysis, which was based on a robust process model of the entire process, was constructed in Aspen HYSYS and calibrated with representative data. Simulations were conducted for the two upgrading schemes in order to generate a detailed inventory of the required energy and utility inputs: process fuel, steam, hydrogen and power. It was concluded that while hydroconversion-based scheme yields considerably higher amount of synthetic crude oil (SCO) than the coker-based scheme (94 wt-% vs. 76 wt-%), it consumes more energy and is therefore more CO₂-intensive (413.2 kg CO₂/m³_SCO vs. 216.4 kg CO₂/m³_SCO). This substantial difference results from the large amount of hydrogen consumed in the ebullated-bed hydroconverter in the hydroconversion-based scheme, as hydrogen production through conventional methane steam reforming is highly energy-intensive and therefore the major source of CO₂ emission. Further simulations indicated that optimization of hydroconverter operating variables had only a minor effect on the overall CO₂ emission due to the complex trade-off effect between energy inputs.

Keywords

Oil sands crude upgrading / hydroconversion / process modeling / greenhouse gas emissions

References

[1] McKellarJ M, CharpentierA D, BergersonJ A, MacLeanH L. A life cycle greenhouse gas emissions perspective on liquid fuels from unconventional Canadian and US fossil sources. International Journal of Global Warming, 2009, 1(1-3): 160-178

[2] BurkhardJ, ForrestJ, GrossS. Oil sands, greenhouse gases, and European oil supply: Getting the numbers right. IHS CERA Special Report, April 2011

[3] Environment Canada. 1990-2010: Greenhouse Gas Sources and Sinks in Canada. National Inventory Report, 2012

[4] FurmiskyE. Emissions of carbon dioxide from tar sands plants in Canada. Energy & Fuels, 2003, 17(6): 1541-1548

[5] Environment Canada. Canada’s Emissions Trends. October 2013

[6] Ordorica-GarciaG, CroisetE, DouglasP, ElkamelA, GuptaM. Modeling the energy demands and greenhouse gas emissions of the Canadian oil sands industry. Energy & Fuels, 2007, 21(4): 2098-2111

[7] CharpentierA D, BergersonJ A, MacLeanH L. Understanding the Canadian oil sands industry’s greenhouse gas emissions. Environmental Research Letters, 2009, 4(1): 1-11

[8] Alvarez-MajmutovA, ChenJ, MunteanuM. Simulation of bitumen upgrading processes. Petroleum Technology Quarterly, 2013, Q2: 31-35

[9] SaylesS, RomeroS. Understand differences between thermal and hydrocracking. Hydrocarbon Processing, 2011, September: 37-44

[10] YuiS. Producing quality synthetic crude oil from Canadian oil sands bitumen. Journal of the Japan Petroleum Institute, 2008, 51(1): 1-13

[11] YuiS, ChungK H. Processing oil sands bitumen is Syncrude’s R&D focus. Oil & Gas Journal, 2001, 99(17): 46-53

[12] MorawskiI, Mosio-MosiewskiJ. Effects of parameters in Ni-Mo catalysed hydrocracking of vacuum residue on composition and quality of obtained products. Fuel Processing Technology, 2006, 87(7): 659-669

[13] Danial-FortainP, GauthierT, MerdrignacI, BudzinskiH. Reactivity study of Athabasca vacuum residue in hydroconversion conditions. Catalysis Today, 2010, 150(3-4): 255-263

[14] YuiS, SanfordE. Mild hydrocracking of bitumen-derived coker and hydrocracker heavy gas oils: Kinetics, product yields, and product properties. Industrial & Engineering Chemistry Research, 1989, 28(9): 1278-1284

[15] YuiS. Removing diolefins from coker naphtha necessary before hydrotreating. Oil & Gas Journal, 1999, 97(36): 64-67

[16] ChangA F, LiuY A. Predictive modeling of large-scale integrated refinery reaction and fractionation systems from plant data. Part 1: Hydrocracking processes. Energy & Fuels, 2011, 25(11): 5264-5297

[17] AncheytaJ. Modeling and simulation of catalytic reactors for petroleum refining. Hoboken, N J: John Wiley & Sons, Inc., 2011, 211-308

[18] NyoberJ. A review of energy consumption in Canadian oil sands operations: Heavy oil upgrading 1990, 1994 to 2001. Canadian Industry Energy End-use Data and Analysis Centre, 2003

[19] SpathP L, MannM K. Life cycle assessment of hydrogen production via natural gas reforming. Technical Report NREL/TP-570-27637, National Renewable Energy Laboratory, February 2001