(7c) CO2 Major Accident Hazards Awareness

Carbon dioxide (CO2) capture, transportation, injection and geological storage (CCS) requires the linking and integration of separate process activities to capture CO2 at an emitter facility, transport it to designated storage sites, and then inject it deep underground for permanent geological storage.

In terms of scale, the amount of CO2 to be handled within a commercial CCS operation may be in the order of thousands of CO2 tonnes per hour, with transportation systems likely to have inventories 10 times more. CCS operations may range in complexity from relatively simple point-to-point chains with a single capture facility, storage site and interconnecting pipeline, to multiple capture plants feeding CO2 into a network of pipelines from which the CO2 is supplied to multiple storage sites.

Many aspects of CCS have been successfully deployed in various industries and therefore there is a wealth of experience available. The challenge facing the emerging CCS industry is to take existing and new technologies, experience and practices, ensure their suitability for use in CCS, and then integrate the various links in the CCS chain together to create an efficient, optimized and demonstrably safe operation.

Appreciation of the potential hazards posed by large scale CO2 releases will be discussed, including the inhalation effects. There are several integrity threats related to CO2 and potential stream impurities that are also recognized. Also the phase behavior of CO2 and the potential impact of impurities is discussed. Propagating pipeline cracks are a concern for CO2 pipelines to be considered in design.

CO2 has unique properties that must be understood and managed when handling such large quantities over different systems and potentially different locations. Over the last decade, DNV has participated in joint industry projects and large-scale testing to understand the potential hazards of CO2. Guidance has been developed to focus and raise awareness of important CO2 properties that may lead to or contribute to major accident events.