Abstract: Aspects of the invention disclosed herein generally provide a heat engine system, a turbopump system, and methods for lubricating a turbopump while generating energy. The systems and methods provide proper lubrication and cooling to turbomachinery components by controlling pressures applied to a thrust bearing in the turbopump. The applied pressure on the thrust bearing may be controlled by a turbopump back-pressure regulator valve adjusted to maintain proper pressures within bearing pockets disposed on two opposing surfaces of the thrust bearing. Pocket pressure ratios, such as a turbine-side pocket pressure ratio (P1) and a pump-side pocket pressure ratio (P2), may be monitored and adjusted by a process control system. In order to prevent damage to the thrust bearing, the systems and methods may utilize advanced control theory of sliding mode, the multi-variables of the pocket pressure ratios P1 and P2, and regulating the bearing fluid to maintain a supercritical state.

Abstract: Aspects of the invention disclosed herein generally provide a heat engine system, a turbopump system, and methods for lubricating a turbopump while generating energy. The systems and methods provide proper lubrication and cooling to turbomachinery components by controlling pressures applied to a thrust bearing in the turbopump. The applied pressure on the thrust bearing may be controlled by a turbopump back-pressure regulator valve adjusted to maintain proper pressures within bearing pockets disposed on two opposing surfaces of the thrust bearing. Pocket pressure ratios, such as a turbine-side pocket pressure ratio (P1) and a pump-side pocket pressure ratio (P2), may be monitored and adjusted by a process control system. In order to prevent damage to the thrust bearing, the systems and methods may utilize advanced control theory of sliding mode, the multi-variables of the pocket pressure ratios P1 and P2, and regulating the bearing fluid to maintain a supercritical state.

Abstract: Aspects of the invention disclosed herein generally provide a heat engine system, a turbopump system, and methods for lubricating a turbopump while generating energy. The systems and methods provide proper lubrication and cooling to turbomachinery components by controlling pressures applied to a thrust bearing in the turbopump. The applied pressure on the thrust bearing may be controlled by a turbopump back-pressure regulator valve adjusted to maintain proper pressures within bearing pockets disposed on two opposing surfaces of the thrust bearing. Pocket pressure ratios, such as a turbine-side pocket pressure ratio (P1) and a pump-side pocket pressure ratio (P2), may be monitored and adjusted by a process control system. In order to prevent damage to the thrust bearing, the systems and methods may utilize advanced control theory of sliding mode, the multi-variables of the pocket pressure ratios P1 and P2, and regulating the bearing fluid to maintain a supercritical state.

Abstract: Aspects of the invention generally provide a heat engine system and a method for activating a turbopump within the heat engine system during a start-up process. The heat engine system utilizes a working fluid circulated within a working fluid circuit for capturing thermal energy. In one exemplary aspect, a start-up process for a turbopump in the heat engine system is provided such that the turbopump achieves self-sustained operation in a supercritical Rankine cycle. Bypass and check valves of a start pump and the turbopump, a drive turbine throttle valve, and other valves, lines, or pumps within the working fluid circuit are controlled during the turbopump start-up process. A process control system may utilize advanced control techniques of the control sequence to provide a successful start-up process of the turbopump without over pressurizing the working fluid circuit or damaging the turbopump via low bearing pressure.

Abstract: Systems and methods for controlling a heat engine system are provided. One method includes initiating flow of a working fluid through a working fluid circuit having a high pressure side and a low pressure side by controlling a pump to pressurize and circulate the working fluid through the working fluid circuit and determining a configuration of the working fluid circuit by determining which of a plurality of waste heat exchangers and which of a plurality of recuperators to position in the high pressure side of the working fluid circuit. The method also includes determining, based on the determined configuration of the working fluid circuit, for each of a plurality of valves, whether to position each respective valve in an opened position, a closed position, or a partially opened position and actuating each of the plurality of valves to the determined opened position, closed position, or partially opened position.

Abstract: Aspects of the invention disclosed herein generally provide a heat engine system, a turbopump system, and methods for lubricating a turbopump while generating energy. The systems and methods provide proper lubrication and cooling to turbomachinery components by controlling pressures applied to a thrust bearing in the turbopump. The applied pressure on the thrust bearing may be controlled by a turbopump back-pressure regulator valve adjusted to maintain proper pressures within bearing pockets disposed on two opposing surfaces of the thrust bearing. Pocket pressure ratios, such as a turbine-side pocket pressure ratio (P1) and a pump-side pocket pressure ratio (P2), may be monitored and adjusted by a process control system. In order to prevent damage to the thrust bearing, the systems and methods may utilize advanced control theory of sliding mode, the multi-variables of the pocket pressure ratios P1 and P2, and regulating the bearing fluid to maintain a supercritical state.

Abstract: Aspects of the invention generally provide a heat engine system and a method for activating a turbopump within the heat engine system during a start-up process. The heat engine system utilizes a working fluid circulated within a working fluid circuit for capturing thermal energy. In one exemplary aspect, a start-up process for a turbopump in the heat engine system is provided such that the turbopump achieves self-sustained operation in a supercritical Rankine cycle. Bypass and check valves of a start pump and the turbopump, a drive turbine throttle valve, and other valves, lines, or pumps within the working fluid circuit are controlled during the turbopump start-up process. A process control system may utilize advanced control techniques of the control sequence to provide a successful start-up process of the turbopump without over pressurizing the working fluid circuit or damaging the turbopump via low bearing pressure.

Abstract: Embodiments of the invention generally provide a heat engine system, a method for generating electricity, and an algorithm for controlling the heat engine system which are configured to efficiently transform thermal energy of a waste heat stream into electricity. In one embodiment, the heat engine system utilizes a working fluid (e.g., sc-CO2) within a working fluid circuit for absorbing the thermal energy that is transformed to mechanical energy by a turbine and electrical energy by a generator. The heat engine system further contains a control system operatively connected to the working fluid circuit and enabled to monitor and control parameters of the heat engine system by manipulating a power turbine throttle valve to adjust the flow of the working fluid. A control algorithm containing multiple system controllers may be utilized by the control system to adjust the power turbine throttle valve while maximizing efficiency of the heat engine system.

Abstract: Provided herein are heat engine systems and methods for starting such systems and generating electricity while avoiding damage to one or more system components. A provided heat engine system maintains a working fluid (e.g., sc-CO2) within the low pressure side of a working fluid circuit in a liquid-type state, such as a supercritical state, during a startup procedure. Additionally, a bypass system is provided for routing the working fluid around one or more heat exchangers during startup to avoid overheating of system components.

Abstract: A heat engine system and a method for generating electrical energy from the heat engine system are provided. The method includes circulating via a turbo pump a working fluid within a working fluid circuit of the heat engine system. The method also includes transferring thermal energy from a heat source stream to the working fluid by at least a primary heat exchanger, feeding the working fluid into a power turbine and converting the thermal energy from the working fluid to mechanical energy, and converting the mechanical energy into electrical energy by a generator coupled to the power turbine. At least one valve operatively coupled to a control system is modulated in order to synchronize the generator with an electrical grid. A generator breaker is closed such that the generator and electrical grid are electrically coupled and the electrical energy is supplied to the electrical grid.

Abstract: Provided herein are a heat engine system and a method for managing a working fluid in the heat engine system during an emergency shutdown. The heat engine system utilizes a working fluid (e.g., sc-CO2) contained within a working fluid circuit to absorb and transport heat. An inventory system is coupled to the working fluid circuit and configured to receive and store at least a portion of the working fluid in the working fluid circuit during an emergency shutdown process. An attemperation line is coupled to the working fluid circuit upstream one or more heat exchangers and configured to direct a portion of the working fluid flow around at least one or more heat exchangers, thereby managing the temperature of the working fluid in the working fluid circuit.

Abstract: Systems and methods for controlling a heat engine system are provided. One method includes initiating flow of a working fluid through a working fluid circuit having a high pressure side and a low pressure side by controlling a pump to pressurize and circulate the working fluid through the working fluid circuit and determining a configuration of the working fluid circuit by determining which of a plurality of waste heat exchangers and which of a plurality of recuperators to position in the high pressure side of the working fluid circuit. The method also includes determining, based on the determined configuration of the working fluid circuit, for each of a plurality of valves, whether to position each respective valve in an opened position, a closed position, or a partially opened position and actuating each of the plurality of valves to the determined opened position, closed position, or partially opened position.

Abstract: Embodiments of the invention generally provide a heat engine system, a method for generating electricity, and an algorithm for controlling the heat engine system which are configured to efficiently transform thermal energy of a waste heat stream into electricity. In one embodiment, the heat engine system utilizes a working fluid (e.g., sc-CO2) within a working fluid circuit for absorbing the thermal energy that is transformed to mechanical energy by a turbine and electrical energy by a generator. The heat engine system further contains a control system operatively connected to the working fluid circuit and enabled to monitor and control parameters of the heat engine system by manipulating a power turbine throttle valve to adjust the flow of the working fluid. A control algorithm containing multiple system controllers may be utilized by the control system to adjust the power turbine throttle valve while maximizing efficiency of the heat engine system.

Abstract: Provided herein are heat engine systems and methods for starting such systems and generating electricity while avoiding damage to one or more system components. A provided heat engine system maintains a working fluid (e.g., sc-CO2) within the low pressure side of a working fluid circuit in a liquid-type state, such as a supercritical state, during a startup procedure. Additionally, a bypass system is provided for routing the working fluid around one or more heat exchangers during startup to avoid overheating of system components.

Abstract: Aspects of the invention disclosed herein generally provide heat engine systems and methods for recovering energy, such as by generating electricity from thermal energy. Generally, the heat engine system has a working fluid circuit containing a working fluid (e.g., sc-CO2) for absorbing thermal energy from the heat source stream via a heat exchanger. In one aspect, the method includes controlling a power turbine by modulating a turbo pump throttle valve and a power turbine bypass valve to adjust the flowrate of the working fluid entering the power turbine while monitoring and controlling process operation parameters of the heat engine system to synchronize the frequency of the power generator to the frequency of the electrical grid during a synchronization process.