Off-Nominal Component Performance in a Supercritical Carbon Dioxide Brayton Cycle

Abstract

Bechtel Marine Propulsion Corporation (BMPC) is testing a supercritical carbon dioxide (sCO2) Brayton system at the Bettis Atomic Power Laboratory. The integrated system test (IST) is a simple recuperated closed Brayton cycle with a variable-speed turbine-driven compressor and a constant-speed turbine-driven generator using sCO2 as the working fluid designed to output 100 kWe. The main focus of the IST is to demonstrate operational, control, and performance characteristics of an sCO2 Brayton power cycle over a wide range of conditions. Therefore, the IST was designed to operate in a configuration and at conditions that support demonstrating the controllability of the closed sCO2 Brayton cycle. Operating at high system efficiency and meeting a specified efficiency target are not requirements of the IST. However, efficiency is a primary driver for many commercial applications of sCO2 power cycles. This paper uses operational data to evaluate component off-nominal performance and predict that design system operation would be achievable.

Search for optimum renewable mix for Australian off-grid power generation

“…Recuperator approach temperature difference (conservative value and can easily be achieved using commercial units) The efficiency of the sCO 2 Brayton cycle increases with increasing turbine inlet temperature. The assumed efficiency at each temperature considered in this study is presented in Table 3 [15,35,36]. Higher temperatures necessitate high performance materials in the power cycle and receiver to prevent degradation, thereby increasing component costs [15].…”

Numerical Analysis of Labyrinth Seal Performance for the Impeller Backface Cavity of a Supercritical CO2 Radial Inflow Turbine

“…Due to this, improving radial inflow turbine (RIT) performance is one of the major topics in both academic researches and industrial practices. Many institutions such as Sandia National Laboratory (SNL) [4,5], Bechtel Marine Propulsion Corporation [6,7] and Nuclear Power Institute of China [8] have investigated RIT performance through experiments. Other researchers, e.g., Zhou et al [9,10] and Unglaube et al [11] have conducted theoretical analyses or numerical simulations to clarify the flow mechanism in S-CO 2 RIT.…”

Off-design and annual performance analysis of supercritical carbon dioxide cycle with thermal storage for CSP application

“…Linares et al [13] proposed a modification to RCBC that facilitate heat addition at a lower pressure to enable the use of conventional shell and tube heat exchangers in order to reduce the cost of the PHEX for CSP applications. Clementoni et al provided the steady-state [14], off-design [15] and transient [16] operational results of a 100kWe experimental facility at the Naval Nuclear Laboratory, USA. Clementoni et al [17] also reported the operational results of the test facility for different compressor inlet temperature (CIT).…”

“…Inventory control turndown is limited, however, by the size of the CO2 storage tank and the pressure pinch between that storage tank pressure and the system pressure. Although a bigger inventory storage tank can push the sCO2 cycle turndown ratio further, the optimal size is an economical trade-off between the CAPEX and improvement in annual energy generation [15].…”