Direct contact steam generation technology has been developed by a group of research scientists, engineers, and technicians by CanmetENERGY-Ottawa. The technology was developed to clean tailings ponds, while producing clean steam that was initially intended to be put back into reservoirs.
DCSG technology has been developed to run in a variety of conditions. It uses water as a moderator during combustion of solid, liquid, or gaseous fuel. This can be performed in a pressurized air, oxygen-rich, or pure oxygen environment. The steam created is sent on to a quench section where more water is added creating a superheated steam/CO2 mixture at elevated pressures. During testing, the DCSG was run at pressures of 30, 55, and 80 bar in an oxygen-rich environment using natural gas as a fuel.
DCSG technology treats the water by passing it through an oxy-fired flame. This creates a molten slag from the inorganic contaminants within the water source. The flame also removes any residual hydrocarbons from within the water source. The steam is then sent through a quench and scrubber to further remove contaminants and results in a steam/CO2 mixture that is suitable for injection back into a reservoir. This technology should reduce the cost of water treatment; however, it poses new issues such as CO2 capture and the cost of oxygen generation vs CO2 utilization.
The final products of the technology are a steam/CO2 mixture and an inorganic molten slag. The consistency of the inorganic slag is similar to gravel. More testing needs to be done to test the leachability of the slag produced, and if there is significant evidence that it has no negative environmental impacts, the slag could be landfilled, or more ideally, used in paving applications in the North. The steam/CO2 mixture would ideally be able to be pumped back into the well for more bitumen mining, or the CO2 could be captured. Results have been promising thus far.