The goals of this project are to develop a process where alkali metal will reduce and scavenge sulfur and nitrogen contained in shale oil in the presence of hydrogen, and also to demonstrate electrolysis of the alkali polysulfide to alkali metal and sulfur.

Ceramatec, Inc

Collaborators
Companies providing oil samples of at least five (5) gallons include Chevron, Oil Shale Exploration Company (OSEC), and Red Leaf Resources, Inc.

Work performed by Esso/Exxon in the 1970s found sodium to be effective at removing sulfur and heavy metals from bitumen and oil refinery residues and bottoms; in one case, nitrogen level was also reduced. That effort was expanded to examine the effectiveness of sodium and lithium for nitrogen removal. Previous work by Esso/Exxon also proposed using beta aluminum as a membrane for electrolytic regeneration of sodium. This work builds on that concept, but instead uses NaSicon and LiSicon-based membranes to eliminate water reactions.

This project will develop a new technology to upgrade shale oil by utilizing alkali metals to remove nitrogen, sulfur, and other heavy metals, as well as a method to electrolytically regenerate the alkali metals used in the process. The three technical focus areas include:

• Upgrading the technology development process by reacting shale oil under various conditions that are designed to increase product quality and minimize resource utilization.
• Developing an electrolytic process to regenerate alkali metal from alkali metal sulfide, as well as performing research to develop the seals and ionically-conductive membranes used in the process.
• Performing a cost and benefits analysis of these processes.

Successful development of this technology may provide potential developers of shale oil resources the ability to upgrade oil after retorting, but prior to refining. Currently, only the hydro-treating process is available, which requires considerable hydrogen and may over saturate the oil. The Green River Basin shale oil resource contains over one trillion barrels. This technology may contribute toward developing this important energy resource and reduce our nation’s dependence on foreign oil supplies.

• Experiments using a Coker Diesel feedstock were conducted and results showed 98% sulfur removal.
• Two Athabasca bitumen feed stocks were tested. In both cases, the API gravity of the feedstock increased from 8 to 20, with removal of up to 95% of the sulfur. Also, volumetric liquid yields in excess of 90% were obtained.
• A thermal pre-treating process to improve the efficiency of separating sodium sulfide from the solids generated in the upgrading reactions was developed and tested.
• Electrolysis of pretreated sodium sulfide-containing solids obtained from a hydrogen upgrading run of Athabasca bitumen was successfully demonstrated.
• An analysis of the operational and capital costs associated with the electrolytic process to produce sodium metal from sodium hydroxide was conducted. The estimates are based on a 25,000 barrel per day upgrading plant. Operating costs are estimated at $1.98 per kilogram of sodium and capital costs range from $0.08 to $0.15 per kilogram of sodium.
• Electrolysis of sodium sulfide at temperatures of molten sodium was conducted and showed very encouraging results.
• A method to synthesize sodium polysulfides by electrochemically reacting sodium metal with sulfur across an NaSicon membrane was successfully implemented.
• An improved lithium conductive membrane was fabricated hermetically for the first time. This material is over 10x more conductive than the membrane material previously demonstrated to be hermetic. Sodium conductive membranes are on the order of 2–3mS/cm conductivity at room temperature and lithium conductive membranes are about 0.2 mS/cm.
• The lithium conductive membrane was tested for a total of 176 hours at 60°C with no apparent deterioration.
• A sodium conductive membrane was tested for over 40 hours at 110°C with no apparent deterioration.
• Reactor runs with shale oil resulted in 66.6% nitrogen and 97.7% sulfur removal with sodium as the alkali metal and hydrogen gas as the hydrogen source. Those runs using methane as the hydrogen source resulted in 54.4% nitrogen and 40.4% sulfur removal.

The project has been completed and the process has demonstrated high levels of sulfur and metals removal from a variety of shale oil, heavy oil, or bitumen feedstocks while in most cases increasing API gravity. Nitrogen removal was less successful. Ceramatec is currently communicating with potential industry partners. DOE is awaiting a final technical report.

$3,788,736

$947,186

NETL – Robert Vagnetti (robert.vagnetti@netl.doe.gov or 304-285-1334)
Ceramatec, Inc – John Gordon (johng@ceramatec.com or 801-978-2138)

Heavy Oil Upgrading Without Hydrogen [PDF-814KB] Paper presented at the 2011 Gas and Oil Expo and Conference, June 7-9, 2011

Progress Reports

Final Project Report [PDF-1.60MB] January, 2013