GHG emissions from a novel partial upgrading technology
Process Ecology was engaged by a technology company to estimate the GHG emissions of a novel partial upgrading technology for partial upgrading of oil sands derived bitumen. The study considered the integration of this new technology in a SAGD Central Processing Facility, in an oil sands mine and extraction facility and in a crude oil terminal with different heavy oil feedstocks.
The GHG wells-to-tank life cycle assessment (WTT LCA) was used to quantify the GHG impact of the technology and compare it to baseline configurations. The following elements were included in the analysis:
- Upstream – scope 1: Aspen HYSYS simulation models were developed for each configuration which were used to estimate the stationary fuel combustion. Industry data was used to estimate other GHG emissions such as flaring, venting, fugitive, and on-site transportation.
- Upstream – scope 2: GHG emissions associated with import or export of electricity were estimated using grid emission benchmarks. Different scenarios were developed to capture future trends on grid emissions including a “net zero” case.
- Downstream – crude transport: emissions associated with the transportation of the crude blend or partially upgraded bitumen to a refinery in the US Midwest.
- Downstream – crude refining: the Petroleum Refinery Life Cycle Inventory Model (PRELIM) tool was used to estimate the GHG emissions associated with the processing of each crude in a refinery.
- Downstream – product transport: emissions resulting from the transportation of final refined products were part of the analysis.
SAGD Central Processing Facility
This baseline was developed using the COSIA SAGD Reference Facilities which is publicly available. The selected case is based on a bitumen production of 33,000 bpd using a steam-oil-ratio (SOR) equal to 3.0, mechanical lift at the reservoir (higher emulsion temperature), evaporators for water treatment, once-through steam generators (OTSG) for boilers and no cogeneration.
Using the Heat & Material Balance for standalone application of the new partial upgrading technology, Process Ecology developed different configurations to maximize the integration between the SAGD CPF and the new technology. In one of the configurations, Process Ecology demonstrated that it is possible to recover waste heat from the upgrading process to generate steam in a heat exchanger instead of a conventional boiler. This configuration has many advantages when compared to the typical water treatment + steam generators scheme used in industry. As a result of the tight heat integration, some of the configurations showed lower upstream (scope 1 + 2) emissions.
Because of the high quality of the partial upgraded product, the downstream emissions are lower than the baseline in all configurations, so that as a result, the WTT LCA emissions are lower in all configurations analyzed in the study.
Oil Sands Mining and Extraction
The study looked at a paraffinic froth treatment configuration, based on the COSIA Reference Facility which is publicly available.
The new partial upgrading facility takes as feedstock the neat bitumen out of the solvent recovery unit. Excess heat from the partial upgrading process is used to preheat the process water in the extraction process, resulting in a reduction of upstream scope 1 emissions. When upstream scope 1 and 2 emissions are combined, the emissions of the new partial upgrading technology are slightly higher than the baseline.
Like the SAGD configurations, the downstream emissions for refining the partially upgrader bitumen are lower than the PFT dilbit baseline, so that the WTT LCA emissions are lowered when the novel partial upgrading technology is employed.
Crude Terminals
The proposed new bitumen partial upgrading technology can also be deployed as standalone in crude terminals. Although there is no host to use any waste heat from the process, it is possible to use the offgas byproduct to generate electricity and export to the grid. Waste heat can also be used to generate electricity in an Organic Rankine Cycle. Some configurations were developed where a diluent recovery unit is used to fractionate diluent prior to upgrading. Diluent can be returned to producers while the partially upgraded bitumen is shipped to refiners. The WTT LCA emissions of the paths processing the new partial upgrading technology are lower than the corresponding baseline feedstocks.
Selected results are summarized in the figure below:
Process Ecology expertise in conceptual process design, process simulation, GHG quantification was critical for the success of the study. We are proud to have helped this technology developer in bringing their innovative process to market.
By Denis Westphalen, Ph.D, P.Eng. - Sr. Technical Advisor
