As general restrictions for the design of Oxyfuel pulverised coal-fired (PC) steam generators are commonly known, the purpose of this work is to show general restrictions for the design of an Oxyfuel coal-fired steam generator using a circulating fluidised bed combustor (CFBC) with external heat exchangers (EHEs). For the CFBC restrictions result on the one hand out of the used fuels composition. On the other hand certain restrictions out of state-of-the-art and steam generator geometries have to be considered within the design.