CERAMIC TUBULAR PRODUCTS, LLC — Department of Energy SBIR Phase I: 30f

Description

In Topic 30.f. DOE requests small business proposals to develop advanced components for energy conversion systems that support supercritical carbon dioxide (sCO2) Brayton power cycle systems. Such power cycles offer increased conversion efficiency, over 50%, as compared to current systems, and are therefore of interest for advanced high temperature nuclear power plants, as well as for Generation 3 Concentrated Solar Power and more efficient advanced fossil power plants. Specifically, DOE asks for proposals to develop piping systems that can accommodate 900 oC turbine inlet temperature conditions. Previous work sponsored by the DOE have focused on using high nickel alloy piping systems that can handle temperatures up to 750 oC. However these alloys showed significant corrosion when exposed to sCO2 at these high temperatures, and also lose much of their strength at such high temperatures requiring extremely thick and costly piping. Silicon Carbide (SiC) ceramic materials demonstrated better corrosion behavior in sCO2, and are known to retain high strength capability up to 1200 oC, thus allowing reasonable thickness piping leading to much lower cost. However, this SiC ceramic material has not been seriously considered for high temperature piping because of concerns over brittle failure. Ceramic Tubular Products has solved this problem with an innovative approach that combines an inner layer of monolithic Silicon Carbide ceramic which is hermetic, with an outer layer of Ceramic Matrix Composite that is not brittle and behaves with a stress - strain relationship similar to metals. We have demonstrated the ability of our product to serve as Accident Tolerant Fuel cladding for current LWR nuclear power plants, with commercial demonstration planned in the next few years as part of a joint DOE - industry program. We believe our product can also be applied to the very high pressure, high temperature, Brayton energy cycle systems, operating initially at temperatures up to 720 oC, and eventually at temperatures up to 900 oC. We are also evaluating the application of this material for use as Solar Receiver tubes in molten chloride salt based Concentrated Solar Power systems operating at temperatures up to 800 oC, under a Small Business Voucher program at Sandia Labs sponsored by DOE EERE. We believe our unique tubular material can be adapted to the larger diameter piping systems (6 to 14" diameter) needed for commercial Brayton power cycles, operating at temperatures up to 900 oC. We are proposing an SBIR project to demonstrate this potential. In Phase 1 we will demonstrate feasibility by fabricating multilayered ceramic piping using existing off the shelf Hexoloy 3 inch SiC tubes, winding the composite layer using two different low cost commercial grade ceramic fibers and then infiltrating the composite layer with a low cost Silicon Oxy- Carbide polymer. CTP will then perform a series of mechanical and thermal tests on sections of these tubes to determine properties. We have also arranged for a 2000 hour test at DOE's Sandia Laboratories to demonstrate the compatibility of SiC piping with supercritical CO2 at 900 oC. Pending success of the Phase 1 project, we propose a Phase II project to scale up the size and manufacturing capability and pipe size as needed to support a Brayton cycle demonstration project (cost shared with industry) currently being considered by DOE under nuclear, fossil and EERE programs. Phase II will include longer term high pressure durability tests, demonstration of recently developed joining techniques to replace the field welding function used for metal alloy piping systems, and acquiring the data needed to achieve certification of our piping material by ASME code committees. Commercial Applications: This work proposed, if successful, will enable the completion of one or more joint industry-DOE Brayton cycle demonstration projects, and subsequent commercial projects using the high efficiency Brayton cycle to convert advanced nuclear energy, concentrated solar energy, and advanced fossil energy heat sources into low cost electricity for US consumers.