Steady-State Power Operation of a Supercritical Carbon Dioxide Brayton Cycle With Thermal-Hydraulic Control

Abstract

The Bechtel Marine Propulsion Corporation (BMPC) Integrated System Test (IST) is a two shaft recuperated closed Brayton cycle using supercritical carbon dioxide (sCO2) as the working fluid. The IST is a simple recuperated Brayton cycle with a variable speed turbine driven compressor and a constant speed turbine driven generator 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. IST operation has reached the point where the system can be run with the turbine-compressor thermal-hydraulically balanced so that the net power of the cycle is equal to the turbine-generator output. In this operating mode, power level is changed by using the compressor recirculation valve to adjust the fraction of compressor flow that goes to the turbines as well as the compressor pressure ratio. Steady-state operational data and trends are presented at various system power levels from near zero net cycle power to maximum operating power using a simplified thermal-hydraulic based control method. Confirmation of stable steady-state operation of the system with automatic thermal-hydraulic control is also discussed.

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).…”

“…Several research groups have performed transient simulations of the standard recompression cycle [10][11][12][13][14], finding that inventory control provides higher efficiency at part load compared to other control techniques such as turbine bypass, turbine inlet temperature and throttling control. 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.…”

Development of Pump-Drive Turbine Module with Hydrostatic Bearing for Supercritical CO2 Power Cycle Application

“…Accordingly, owing to these advantages of sCO 2 power generation, numerous studies are underway, primarily in developed countries. Sandia National Lab (SNL) proposed and tested a 250 kW sCO 2 Brayton cycle [1,2]; Bechtel Marine Propulsion Corporation (BMPC) also proposed a 100-kW CO 2 Brayton cycle integrated system [3,4]. Echogen developed a 7.3-MW sCO 2 power cycle for waste heat recovery system [5].…”