Zigzag Flow Reactor for Metal Oxide Thermochemical Energy Storage
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Solution Overview
Problem
Current thermochemical energy storage (TCES) reactors face challenges in achieving high output energy storage density, power density, and scalability, which are essential for minimizing the levelized cost of storage (LCOS) and ensuring reliable medium-term energy storage for renewable energy grids.
Innovation Solution
The zigzag flow reactor (ZFR) design, featuring a vertical heated channel with inclined, vertically stacked metal meshes and a counterflowing inert sweep gas, allows for efficient heating and reduction of metal oxide particles, maximizing power density and scalability while storing thermal energy reversibly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional TCES reactor designs are used, then basic energy storage function is achieved, but output energy storage density and power density remain low
Solution Approach 1:
The reactor is segmented into multiple functional zones: a fluidized bed reduction zone for high-temperature reduction reactions, a transition zone for particle cooling and oxygen partial pressure adjustment, and a storage zone for reduced particles. This segmentation allows each zone to optimize for its specific function, achieving high energy storage density without excessive overall complexity.
Solution Approach 2:
The invention transitions from conventional two-dimensional horizontal or vertical flow configurations to a three-dimensional fluidized bed system with vertical particle circulation. Particles are fluidized and circulated upward through the reduction zone, then cooled and stored, creating efficient use of vertical space and improving both energy storage density and power density.
2Volume of moving object
If reactor size is reduced to minimize footprint, then space efficiency improves, but scalability to grid levels becomes difficult
Solution Approach 1:
The reactor system is designed as modular segments that can be stacked or connected in series. Each module contains complete functional units (fluidized bed, transition zone, storage), allowing the system to scale from small demonstration units to grid-level capacity by simply adding more modules without redesigning the entire system.
Solution Approach 2:
The reactor design uses universal components and standardized interfaces that can accommodate different scales and applications. The fluidized bed configuration and particle circulation system are universally applicable across different reactor sizes, enabling seamless scaling from laboratory to commercial deployment.
3Productivity
If continuous operation is implemented, then energy storage capacity increases, but technical challenges in particle flow and gas exchange increase
Solution Approach 1:
The system employs dynamic particle circulation where particles continuously move between fluidized bed, transition zone, and storage areas. Gas flow rates, particle circulation speeds, and temperature profiles are dynamically adjusted to maintain optimal reduction and cooling conditions, enabling continuous operation while managing complexity through active control systems.
Solution Approach 2:
The reactor maintains continuous reduction reactions in the fluidized bed while simultaneously cooling and storing reduced particles in the transition zone. This continuous action eliminates idle time between batches, maximizing productivity. The particle circulation system ensures uninterrupted supply of fresh particles to the reduction zone and continuous removal of reduced particles for storage.
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 ZFR achieves high output energy storage density and power density, enabling affordable scalability and reducing the overall levelized cost of storage, as demonstrated by laboratory prototypes and computational models, with improved particle residence time and gas mixing.
Implementation Method 1
A zigzag flow reactor (ZFR) has been designed to allow for flow of the MOx particles that are heated and reduced (emit O2) in the presence of a counterflowing inert sweep gas.
Implementation Method 2
The reactor devices utilize temperature and oxygen partial pressure dependent transition of continuous reduction states of non-stoichiometric metal oxide compounds, MOx.
Implementation Method 3
During the charging step, a reduction reactor thermally reduces the preheated MOx particles (T ̃550° C.). The heat for this process is supplied from the off-peak power from electrical or thermal sources. During the reduction process, the MOx particles release O2 gas swept out of reactor by an inert gas (typically N2).
Implementation Method 4
The hot and reduced metal oxide particles serve as storage media in a MOx-δ particle storage at ̃1000° C.
Implementation Method 5
During the discharging step, stored MOx-δ particles are sent to the energy recovery reactor (ERR) where they reoxidize using air/O2 which releases the stored sensible and chemical energy.
Data Source
AI summary
The disclosure concerns reactors for reducing metal oxide particles comprising: (a) a vertical heated channel; (b) a plurality of inclined, vertically stacked metal meshes, said meshes comprising: (i) a particle opaque portion comprising over about 50% of the meshes' length and having openings smaller than the smallest particle; and (ii) a particle transparent portion having openings large enough for particles to pass to the next level; (c) a vibration motor coupled to the meshes; and (d) an insulated chamber for storing the particles. Other aspects of the disclosure concern methods of reducing metal oxide particles. Yet other aspects concern thermochemical energy storage reactor devices comprising such reactors.