Thermal Storage for Flexible Carbon Capture
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Solution Overview
Problem
Existing carbon capture systems in power plants are not cost-effective at low capacity factors and flexible operating conditions, especially in high-variable renewable energy penetration markets, due to high energetic requirements for solvent regeneration and reduced net power production.
Innovation Solution
A power plant system incorporating a carbon capture system and a thermal storage system with heat pumps, allowing for the storage and release of thermal energy to support solvent regeneration in the carbon capture system, thereby enhancing net plant capacity and peak power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon capture systems are sized based on maximum CO2 flow rates, then CO2 capture capability is ensured, but net power production is reduced and levelized cost of electricity increases
Solution Approach 1:
The patent implements dynamic sizing of the carbon capture system by introducing a thermal energy storage system that allows the capture system to operate at reduced capacity during low-demand periods while maintaining full capture capability during peak periods. The thermal storage buffer enables the capture system to be sized for maximum capacity but operate flexibly at variable loads, resolving the contradiction between ensuring capture capability and maintaining net power production.
Solution Approach 2:
The patent changes the operational parameters of the carbon capture system by using thermal energy storage to decouple the capture system's sizing from its continuous operation at maximum capacity. The thermal storage allows the system to maintain full CO2 capture capability while operating the capture equipment at lower thermal input during periods of low electricity demand, thereby improving net power production while preserving capture reliability.
2Reliability
If thermal energy is continuously supplied for solvent regeneration, then CO2 capture efficiency is maintained, but net plant capacity is reduced
Solution Approach 1:
The patent applies preliminary action by storing thermal energy in advance during periods of high electricity demand when the carbon capture system operates at full capacity. The thermal energy storage system accumulates heat that can be used later for solvent regeneration during low-demand periods, allowing the plant to maintain CO2 capture efficiency while reducing the immediate thermal energy demand that would otherwise reduce net plant capacity.
Solution Approach 2:
The patent ensures continuous CO2 capture efficiency by maintaining the thermal energy storage system that can supply heat for solvent regeneration at any time. This continuous availability of thermal energy allows the carbon capture system to maintain its efficiency regardless of the plant's current operating mode, while the stored thermal energy prevents continuous thermal energy extraction from reducing net plant capacity during low-demand periods.
3Adaptability or versatility
If power plants operate dynamically to respond to electricity prices, then market flexibility is improved, but capacity factor is reduced and cost pressures increase
Solution Approach 1:
The patent segments the power plant's operational functions by separating the carbon capture system's thermal energy requirements from the main power generation cycle through the introduction of thermal energy storage. This segmentation allows the power plant to dynamically adjust power generation in response to electricity prices while the thermal storage independently manages the carbon capture system's thermal needs, maintaining capacity factor despite dynamic operation.
4Productivity
If heat is extracted from flue gas for power generation, then net power production is increased, but thermal energy available for carbon capture is reduced
Solution Approach 1:
The patent introduces thermal energy storage as an intermediary between the heat recovery steam generator and the carbon capture system. This intermediary buffers the thermal energy flow, allowing heat to be extracted for power generation while the thermal storage system compensates for the reduced thermal energy available for carbon capture by releasing stored heat when needed, thereby maintaining both net power production and thermal energy availability for capture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively increases net plant capacity and peak power output while maintaining high CO2 capture rates, even at low energy demand periods, by utilizing thermal energy storage to support carbon capture operations.
Implementation Method 1
a heat pump configured to transfer heat from the thermal storage system to the carbon capture system
Implementation Method 2
a heat recovery steam generator including at least one heat exchanger and at least one steam turbine, the at least one heat exchanger configured to receive the flue gas and transfer heat from the flue gas to a fluid
Implementation Method 3
a thermal storage system including a hot storage unit configured to store thermal energy at a hot temperature, the hot temperature greater than ambient temperature
Data Source
AI summary
A power plant system is disclosed. The power plant system includes a combustor configured, a turbine configured to generate electricity, a heat exchanger and a steam turbine, a carbon capture system configured to remove at least a portion of carbon-based gasses from the flue gas downstream from the heat recovery steam generator, and a thermal storage system including a hot storage unit configured to store thermal energy at a hot temperature, the hot temperature greater than ambient temperature. The power plant is configured to operate in at least a first mode for storing thermal energy in the thermal storage system and a second mode for releasing the stored thermal energy from the thermal storage system and during the second mode, heat stored in the hot storage unit is transferred to the carbon capture system.