Projects

Projects: Projects for Investigator

To investigate the impact on performance and cost of coal based gasification plant of the installation and operation of CO₂ capture equipment at high pressure.

• Establishing three design cases. A medium pressure CO₂-in Base Case, a medium pressure CO₂-removed case and a high pressure CO₂-removed case.
• Outline the advantages and risks of high pressure IGCC operation compared to medium pressure.
• Carry out an assessment to identify areas in which improvements to equipment are desirable and, if possible, propose solutions. Address expected problem areas namely the operation of lockhoppers at high pressure.
• Develop a device giving improved accuracy in the measurement of dense phase coal flow.

Removal of CO₂ from fossil fuels used in electricity generation is most easily facilitated pre-combustion, and for coal this would imply using Integrated Gasification Combined Cycle (IGCC) technology. The pressure at which IGCC plants operate has, until now, usually been chosen to provide syngas at the right conditions for the gas turbine. Efficiency of these processes is slightly higher than for an equivalent conventional coal-fired power station, and emissions of SO_X, NO_x, particulates, and mercury are significantly better. CO₂ extraction is also possible at these medium pressures (MP) using existing commercially proven equipment. There is, however, some scope to further improve the efficiency of coalfed medium pressure IGCC with or without CO₂ removal: for example using dry- instead of slurryfeeds. The potential return on these could be high in both economic and environmental terms.A financial model will therefore be developed for the medium pressure, CO₂ not removed base case incorporating the best of the above and the effect of removing the CO₂ will be examined. This will provide a basis upon which the advantages of dry-feed high pressure quench gasification can be measured.

There are theoretically a number of advantages in increasing the gasification pressure as high as possible, the limit being the ability of air separation units to supply oxygen. These include the easierremoval of CO₂ suitable for export from the site for long-term storage or use in Enhanced Oil Recovery (EOR). The confidence with which higher gasification pressures can be used is influenced by the extent to which exisiting equipment is required to operate beyond the envelope of current experience. An appraisal is need to establish whether the benefits of HP operation are sufficient to outweigh these costs. The work will therefore also include the results of a high pressure, CO₂ removed financial model, and a clear statement of the techno-economic advantages of high pressure dry fed water quench gasification coupled with CO₂ removal.