Oxygen supply for oxyfuel CO2 capture

This paper presents the results of a study to develop Air Products’ air separation unit (ASU) offerings for oxyfuel coal CO2 capture projects. A scalable “reference plant” concept is described to match particular sizes of power generation equipment, taking into account factors such as safety, reliability, operating flexibility, efficiency, and low capital cost. We describe the selection of a process cycle to exploit the low purity requirements, as well as the options for compression machinery and drivers as the scale of the plant increases and the sizes of referenced equipment limit the possibilities. We also explore integration with other elements of the system, such as preheating condensate or heating and expanding pressurised nitrogen. In addition, we consider how the ASU affects the flexibility of the oxyfuel system and discuss how its power consumption can be reduced during periods of high power demand. Finally, the advantages and disadvantages of different execution strategies for air separation unit projects are discussed, as well as alternative commercial models for the supply of oxygen.

► We present Air Products’ development of air separation units for oxyfuel coal CO2 capture.
► The power consumption of five ASU process cycles is compared on a normalised basis.
► Potential for integration of the ASU with the power cycle and nitrogen consumers is explored.
► We present a scalable reference plant design and describe some commercial models for oxygen supply.