(43c) A Novel High Pressure Oxyfuel Process with Staged Combustion

The application of pure oxygen for the combustion of coal provides the advantage to reduce the gas flow significantly and to operate the combustion and steam production at higher pressure. This results in higher electrical net efficiency and a reduction of investment costs.   A novel approach to high pressure oxyfuel process with staged combustion has been developed and will be presented in this paper.  In this approach, the coal is first gasified to form syngas at high pressure and the syngas is burnt in several stages within compact heat exchangers for steam production.  The recycle of CO₂ is avoided in this approach compared to traditional low pressure oxyfuel processes.  The process also minimizes cooling water.  The main benefits from the application of the above high pressure oxyfuel and staged combustion process include: (i) significant increase in electrical efficiency, (ii) substantial reduction of specific investment costs, (iii) reduction of plant size and footprint for a given power generation capacity, (iv) reduction of steel used for boiler construction, and potential advantages of introducing 700^oC boiler technology.