The EKS-DT process is a technology designed to dewater difficult-to-dewater materials like fluid fine tailings (FFT).
How does the EKS-DT process work?
The EKS-DT process is based on the physics of electrokinetics. Electrophoresis causes fines to break free of electrostatic colloidal forces and to settle rapidly out of suspension. A second electrokinetic reaction, electro-osmosis, causes the bound water in colloidal suspensions and in soils to become mobile; the water is released to the surface. Electrophoresis and electro-osmosis work together to accelerate dewatering.
The EKS-DT process involves two stages. During Stage 1, slurries are dewatered to the point that a soil matrix is formed. Stage 2 involves further dewatering of the soil until a desired water content/strength is achieved. The physics of Stage 1 differ somewhat from those occurring during Stage 2 but both stages involve the same dewatering equipment. The primary difference is modifications to how the power is applied during each stage.
Has the EKS-DT process been proven to work on FFT?
Yes. EKS has been successfully conducting experiments dewatering FFT with the EKS-DT process since 2010. The process has been used successfully by EKS to dewater FFT at various scales using different setups. Through these experiments, EKS has gained considerable understanding and confidence in the technology.
In 2015, EKS set up two larger scale tests (i.e. 130 m3 and 25 m3) at the C-FER facility in Edmonton. These tests were designed to confirm the scalability of the technology among other things. The results confirmed that the technology is scalable and that major energy efficiencies can be achieved during Stage 1 of the process when it is scaled up.
Is the EKS-DT process commercially viable for dewatering FFT?
Yes. EKS has developed a deployment strategy for dewatering FFT commercially at scale in oil sands tailings ponds. This strategy lays out the details for commercially deploying and operating the process. The dewatering costs associated with this deployment and operating strategy are highly competitive.
What remains to be done before the process can be commercially applied to dewater FFT?
EKS is currently in the final stages of its technology development process. The current research is focused on optimising the engineering design and operation of commercial-scale EKS-DT installations. A number of significant innovations have emerged from this research. The results will maximise dewatering reliability and minimised dewatering costs.
The final stage before full-scale commercialisation is to conduct a field demonstration. A large-scale field demonstration is planned for 2019. Commercialisation will follow immediately thereafter.
What are the capital costs associated with the EKS-DT process?
The unit dewatering costs are highly scale dependent. Major economies of scale are available. The larger the mass of FFT to be dewatered, the lower are the unit dewatering costs. The primary fixed capital cost is the electrodes.
The other major capital costs are the power supply and distribution system and the operating control centre. These capital components are not fixed but rather are reusable and transportable from one site to another. As a result, these costs are spread over multiple applications of the technology.
EKS has produced first-order capital cost estimates for a hypothetical mine producing 100,000 bbl/day. Over the life of this case study mine, the capital costs worked out to less than $2.00 per cubic metre of FFT dewatered. These costs would be less for a larger mine. As well, these costs could be reduced by integrating the EKS-DT process in the tailings management plan and optimising the dewatering sequencing.
Are the EKS-DT dewatering costs competitive with existing dewatering technologies?
Yes. EKS does not have access to the actual dewatering costs of individual companies but based on publicly available information, the EKS-DT process is highly cost competitive with existing technologies.
What are the operating costs associated with the EKS-DT process?
The EKS-DT process has no moving parts and requires minimal labour during the dewatering process. The automatic control system is connected via internet and can be operated remotely. The rate of dewatering is directly controlled throughout the dewatering process. Dewatering can be accelerated or slowed down by adjusting the applied power.
Electricity is the major operating cost. The total required electricity depends on:
• The initial water content of the FFT,
• The desired final water content, and
• The rate at which the FFT is to be dewatered.
The EKS-DT process does not require a constant supply of electricity. This allows power to be used during off-peak periods. The system can be shut down during the day when electricity demand is high and restarted when electricity demand is less. The process can be run using onsite renewable energy system. Large variations in the instantaneous power supply do not affect the process negatively.
EKS has produced first-order operating cost estimates for a hypothetical mine producing 100,000 bbl/day. Over the life of this case study mine, the operating costs worked out to less than $1.00 per cubic metre of FFT dewatered. These costs are not based on any balancing of the power usage with power demand or supplementing the power with renewable energy supplies.
What are the material handling costs associated with the EKS-DT process?
The EKS-DT process is designed to be applied in situ. For that reason, the FFT does not need to be dredged out of existing ponds, pumped to a treatment site and then transported to a final disposal area. This feature of the technology results in major cost savings.
Where can the EKS-DT process be used in the oil sands?
As part of its assessment of the commercial viability of the EKS-DT process, EKS has evaluated how the process might be deployed for different applications. The process can be effectively deployed to:
• Dewater legacy FFT in large tailings basins,
• Dewater freshly produced FFT that has not undergone any other dewatering process,
• Further dewater FFT that has been partially dewatered with existing technologies,
• Consolidate the bottom sediments of end-pit lakes,
• Form impervious geotechnically stable caps over unstable partially dewatered FFT deposits,
• Strengthen soft spots in off-spec areas of partially dewatered FFT deposits, and
• Stabilise tailings basin berms.
Can the EKS-DT process be used for other commercial applications?
Yes. Some of the other commercial applications that EKS is pursuing include: