September 25, 2021
CO2 Capture and Multiphase Pumping
As the world moves towards a lower carbon environment the industry is taking a hard look how to handle and transport CO2. It is expected that CO2 sequestration at power plants and larger industrial facilities will be major future undertaking driven by government regulations and carbon taxation. Several of the major independent oil companies have come up with strategies, in some cases detailed plans how to go about capturing, transporting and re-injecting CO2 back in the ground. This business model also contributes to offset some of the effects of their legacy and traditional business. Already some are using CO2 injection as an important EOR tool and are already contributing to the goal of lowering the industry carbon footprint.
CO2 is an omnipresent product that appears in different phases depending on temperature and pressure. For gathering and transport of CO2, the liquid, gas, and miscible phases are of interest. As both conventional liquid pumps and gas compressors are useful in a single-phase operation, there is no option except the multiphase pump that can cover all the different phases, which CO2 can appear in. As phase shift is a prevalent condition when pressure and temperature vary, there are transitory conditions in which liquid and gaseous CO2 exist in pipeline transport, which only a multiphase pump can master. (Attached diagram)
The multiphase pump is of the twin-screw type, which is designed for very high gas load. Accepting low inlet pressure, it is well suited for pressure boosting not restricted by conventional pressure ratio limitations. The pump is adopted for CO2 operations, built in materials not subject to stress corrosion and equipped with a mechanical seal system that can live with the low lubricity of CO2.