3-Stage hauling of biomass residues and its impact on reducing fossil energy footprint of oil sands derived crude

摘要

The Government of Canada has implemented measures to reduce greenhouse gas emissions, including a carbon tax and its proposed Clean Fuel Standard. Alberta's Oil Sands industry, arguably one of Canada's largest and most energy intensive industries, has made significant progress towards improving energy efficiency and reducing its fossil energy footprint, including investigating options for integrating bio-based feedstocks into bitumen extraction and processing. Nevertheless, developing sustainable bioenergy supply chains remains a crucial challenge to reaching this goal.This paper investigates pathways for harvesting and hauling biomass residues to produce bio-oil that can replace fossil fuels used in oil sands bitumen processing. A 3-stage grid model is developed, comprising a square grid distribution of harvesting fields and district centres. Biomass is collected and hauled to fast pyrolysis units centrally located within square harvesting fields. Raw bio-oil is hauled from fields to the centre of one of 11 District centres, where it is stabilized and blended. Stage1 and Stage-2 estimate hauling distance using hypothetical roads described by geometric equations and tortuosity factors. Stage-3 hauling of stabilized bio-oil from District centres to upgraders at Scotford AB and Fort McMurray AB is estimated by using web-based mapping tools and actual road networks. Total diesel requirements for hauling are calculated using total distances obtained from the 3stage hauling model.Average diesel consumption obtained from the model is 0.32 L per 1000 L of bio-oil produced, increasing to 3.45 L per 1000 L bio-oil delivered to district centres. Total diesel consumption is 10.23 and 14.40 L per 1000 L bio-oil delivered to Scotford and Ft. McMurray, respectively. The model shows that co-processing of biomass residues can reduce the fossil energy footprint of processing oil sands synthetic crude oil by 22-28%. The quantity of delivered bio-oil is sufficient to replace petroleum coke and synthetic crude oil used for combustion as well as a substantial fraction of natural gas fuel. Moreover, the model can help to determine the most suitable processing and hauling options at each stage in order to minimize diesel fuel requirements, and the model framework can be extended to other jurisdictions as well as other industries. Crown Copyright (C) 2019 Published by Elsevier Ltd. All rights reserved.