Rotating Drum Calciner With Hermetic Seal For CO2 Capture
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Solution Overview
Problem
Fossil fuel-based power plants using Fully Integrated Regenerative Calcium Cycle (FIRCC) systems face inefficiencies due to suboptimal mixing of heat-transferring particles with limestone in calciners, leading to reduced CO2 capture efficiency and leakage issues from non-hermetically sealed calciners.
Innovation Solution
A system and method that includes a calciner with a rotating drum and an outer shell for hermetic sealing, where heat-transferring particles are mixed with loaded sorbent particles to facilitate endothermic calcination, and an uplift gas stream separates lean sorbent particles, reducing the need for a separate classifier and minimizing air ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a transport gas is used to mix limestone with heat-transferring particles in the calciner, then the limestone can be heated, but optimal mixing is not achieved which reduces calcination efficiency
Solution Approach 1:
The patent uses a fluidized bed system where air is introduced through distributors at the bottom of the calciner to fluidize both the limestone particles and heat-transferring particles. This pneumatic approach creates intense mixing through bubble-induced turbulence and particle circulation, achieving optimal contact between reactants and heat transfer media without complex mechanical mixing devices.
Solution Approach 2:
The patent optimizes operating parameters including air flow rate, particle size distribution, and temperature to achieve optimal fluidization quality. By controlling the gas velocity and particle characteristics, the system maximizes mixing efficiency and heat transfer while maintaining stable fluidization, thereby improving calcination efficiency without increasing device complexity.
2Device complexity
If the calciner is not hermetically sealed, then the structure is simpler, but limestone, heat-transferring particles, and CO2 leak which decreases efficiency
Solution Approach 1:
The patent employs flexible sealing elements including expansion joints and flexible seals at the drum rotation seal to prevent leakage of limestone, heat-transferring particles, and CO2 while accommodating the thermal expansion and rotation of the calciner drum. These flexible sealing mechanisms maintain hermetic sealing without requiring rigid, complex sealing structures.
Solution Approach 2:
The patent maintains a controlled atmosphere within the calciner by hermetic sealing, preventing air ingress that would cool the particles and reduce calcination efficiency. The sealed environment allows maintenance of high temperature conditions necessary for efficient calcination while preventing loss of process materials and CO2 emissions.
3Device complexity
If the calciner is not hermetically sealed, then the structure is simpler, but air ingress is high which reduces efficiency
Solution Approach 1:
The patent uses flexible seals and expansion joints that maintain hermetic sealing while accommodating thermal expansion and drum rotation. These flexible sealing elements prevent air ingress effectively without requiring overly complex rigid sealing mechanisms, thus reducing energy loss from air leakage while maintaining practical device complexity.
4Productivity
If a separate classifier is used to separate HT solids from lean sorbent, then separation is achieved, but the system complexity increases
Solution Approach 1:
The patent combines the classification function with the existing cyclone separator that is already part of the FIRCC system. The cyclone performs dual functions of separating CO2-rich gas from the particle stream and classifying particles by size, eliminating the need for a separate classifier device. This merging of functions achieves effective separation while minimizing system complexity.
Solution Approach 2:
The cyclone separator is designed to perform multiple functions: gas-particle separation, particle classification, and serving as the inlet to the calciner. This multi-functional design eliminates the need for dedicated classification equipment while maintaining effective particle size separation, thereby reducing system complexity without compromising separation efficiency.
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
Enhances CO2 capture efficiency by ensuring optimal mixing and hermetic sealing, reducing thermal energy loss and air ingress, thereby improving the overall FIRCC system performance.
Implementation Method 1
heat-transferring particles are mixed with loaded sorbent particles to facilitate endothermic calcination
Implementation Method 2
The drum rotates such that at least some of the loaded sorbent particles are mixed with heat-transferring particles
Implementation Method 3
The calciner includes an outer shell disposed around the drum so as to hermetically seal the drum
Implementation Method 4
an uplift gas stream separates lean sorbent particles, reducing the need for a separate classifier
Data Source
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AI summary
A system (10) for reducing carbon dioxide emissions from a flue gas is provided. The system (10) includes a carbonator (22) and a calciner (18). The carbonator (22) receives the flue gas and lean sorbent particles such that the lean sorbent particles absorb gaseous carbon dioxide from the flue gas and become loaded sorbent particles. The calciner (18) includes a drum (92) that defines a cavity (94) having a first opening (96) and a second opening (98). The first opening (96) is fluidly connected to the carbonator (22) such that the loaded sorbent particles flow into the cavity (94) from the carbonator (22). The drum (92) rotates such that at least some of the loaded sorbent particles are mixed with heat-transferring particles so as to release the absorbed gaseous carbon dioxide and exit the drum (92) via the second opening (98) as lean sorbent particles.