Capturing CO2 with Geosequestration

Carbon capture and storage (CCS) processes are emerging as a way for reducing carbon dioxide emissions from fossil fuel-based, power generation facilities. Also referred to as geosequestration, it is:

…a natural or manmade reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period.

I exchanged some emails with Murray Cox who had some background on Emerson’s role in Australia’s first geosequestration project. It was designed to demonstrate the deep geological storage or geosequestration of CO2. The Emerson Australian team provided technologies like the DeltaV automation system and DeltaV SIS safety instrumented system, Rosemount measurement devices, Fisher valves, and Micro Motion flow and density measurement in addition to project management and project engineering services. This process was commissioned and has been operating since April 2008.

Murray describes the process of geosequestration. It begins with having the right geological formation to hold the CO2 gas. The site had thick layers of porous sandstone covered with mudstone to prevent leakage of the carbon dioxide gas back into the atmosphere.

For this demonstration project, the CO2 gas is initially collected from a source well that was more than 85% CO2 with the balance methane and other hydrocarbon gases. Separation is the first process to isolate the CO2 gas. It is next compressed to generate a stream of supercritical CO2, which is transported 2-3 km by pipeline to gas injection wells in the natural gas-depleted sandstone formation.

Since this is a pilot project, monitoring the CO2 injected into the formation is a key part of the project. This monitoring will continue for several years to understand how CO2 behaves or changes over time. The trial is meant to determine if this process and method is a viable way to capture and store CO2 produced from fossil fuel-based generating facilities.

A quick check of Wikipedia shows a number of countries involved in geosequestration projects. The viability of these types of projects will be determined as these demonstration projects accumulate run-time data.

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