Transporting the Next Generation of CO_2 for Carbon, Capture and Storage: The Impact of Impurities on Supercritical CO_2 Pipelines

摘要

Climate change has been attributed to greenhouse gases with carbon dioxide (CO_2) being the major contributor. Most of these CO_2 emissions originate from the burning of fossil fuels (e.g. power plants). Governments and industry worldwide are now proposing to capture CO_2 from their power plants and either store it in depleted reservoirs or saline aquifers ('Carbon Capture and Storage', CCS), or use it for 'Enhanced Oil Recovery' (EOR) in depleting oil and gas fields. The capture of this anthropogenic (man made sources of CO_2) CO_2 will mitigate global warming, and possibly reduce the impact of climate change.rnThe United States has over 30 years experience with the transportation of carbon dioxide by pipeline, mainly from naturally occurring, relatively pure CO_2 sources for onshore EOR. CCS projects differ significantly from this past experience as they will be focusing on anthropogenic sources from major polluters such as fossil fuel power plants, and the necessary CO_2 transport infrastructure will involve both long distance onshore and offshore pipelines. Also, the fossil fuel power plants will produce CO_2 with varying combinations of impurities depending on the capture technology used.rnCO_2 pipelines have never been designed for these differing conditions; therefore, CCS will introduce a new generation of CO_2 for transport. Application of current design procedures to the new generation pipelines is likely to yield an over-designed pipeline facility, with excessive investment and operating cost. In particular, the presence of impurities has a significant impact on the physical properties of the transported CO_2 which affects: pipeline design; compressor/pump power; repressurisationrndistance; pipeline capacity. These impurities could also have implications in the fracture control of the pipeline. All these effects have direct implications for both the technical and economic feasibility of developing a carbon dioxide transport infrastructure onshore and offshore.rnThis paper compares and contrasts the current experience of transporting CO_2 onshore with the proposed transport onshore and offshore for CCS. It covers studies on the effect of physical and transport properties (hydraulics) on key technical aspects of pipeline transportation, and the implications for designing and operating a pipeline for CO_2 containing impurities.rnThe studies reported in the paper have significant implications for future CO_2 transportation, and highlight a number of knowledge gaps that will have to be filled to allow for the efficient and economic design of pipelines for this 'next' generation of anthropogenic CO_2.