The Energy Research Center in co-operation with Vitkovice Power Engineering ltd. designed and tested a new device which can serve as an integral part of a zero emission combined cycle with the CES combustor. In the primary circuit of the decarbonizing steam generator condensation of steam and separation process take place at increased pressure (approx. 3-6 bar). The released heat is transferred to the secondary circuit where a pure low-pressure steam is produced. The experimental runs proved that effective separation is possible even at low temperature gradient caused by high concentration of CO2 which prevents steam from reaching the heat transfer surface. Nevertheless some additional upgrades were required in order to utilize relatively substantial amount of waste heat in exiting mixture. This is a possible way how to improve CO2 purity and thermal efficiency of the separator, thus another supporting exchanger has been installed directly behind the separator for the purpose of feedwater preheating. This so-called aftercooler was made in two variations in order to investigate effect of flow regime and surface arrangement on intensity of heat transfer between the mixture and feedwater. The article presents results of performance of the separator with the aftercooler at various mixture compositions and pressure differences.
