More efficient electric power generation can be achieved using supercritical carbon dioxide (sCO2) technologies. For these power generation systems to operate cost effectively, the system joints, especially piping, should be able to withstand stresses induced by high operating temperatures and pressures, and the associated thermal expansion, without sCO2 leaking across the seals. These advanced couplings contribute to maximizing the efficiency of advanced fossil energy power generation systems and containing capital and operating costs. Currently, there is no cost-effective sealing method that can meet industry requirements. For this proposal, the focus is the development of a coupling assembly which comprises a dynamic seal mechanism capable of handling the thermal expansion coming from high-temperature environments and yet seals under the high-pressures sCO2 conditions. The coupling will be designed so it is readily welded to pipe runs or flange connection. More importantly, in either case, it allows for a quick connect/disconnect mechanism. To achieve the objectives of this proposal, the proposer will leverage their decades of expertise gained from previous works including: 1) High-pressure/high-temperature seals for static applications; 2) High-pressure/low-temperature seals for dynamic applications; 3) High-pressure/high-temperature dynamic seals for heat exchangers. This knowledge base will be combined with new materials and coatings to design an advanced coupler scalable to piping sizes from 8 to 24 inches. During Phase 1 this work will focus on 1) increasing the advanced couplings operating temperature and pressure range to 700-800°C at sCO2 pressures of 300 bar; 2) designing a reliable dynamic seal; and 3) designing for a quick connect/disconnect mechanism. Key activities include material selection and tribology testing under representative environmental conditions. An advance coupler that serves as a joining technology that can handle these extreme conditions would open up power plant design space and allow for some design freedom leading to lower plant costs and therefore, the lower cost of electricity. A further benefit of this development is that the same concept can be also used for lower- temperature quick disconnect couplings. Currently quick disconnect couplings that accommodate linear expansion do not exist. The result of this effort will be the development of a quick coupling mechanism that is ready for mass production driving the cost down and providing an economically viable solution for high temperature/pressure sCO2joints and a host of other commercial applications.
