CO2 Capture Solvent System Heat Rate Reduction
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Solution Overview
Problem
Current carbon dioxide capture processes using chemical solvents are energy-intensive, leading to high costs and increased CO2 emissions due to the need for heat generation, which complicates the capture process and reduces plant output.
Innovation Solution
A solvent system comprising a chemical solvent, a high dielectric physical solvent, and water, where the physical solvent replaces part of the water, reducing the heat rate by minimizing steam vaporization and optimizing ionization, and includes a process configuration with a splitter, cross-exchanger bypass, and lean vapor compressor to enhance energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional chemical solvent processes are used to capture CO2, then CO2 absorption capacity is improved, but energy consumption increases due to high heat rate requirements
Solution Approach 1:
The patent changes the chemical composition parameters of the solvent system by introducing a physical solvent (triethylene glycol) alongside the chemical solvent (MEA). This compositional parameter change modifies the absorption mechanism to reduce the heat rate required for CO2 capture while maintaining absorption capacity
Solution Approach 2:
The patent employs a composite solvent system combining chemical solvent (MEA) and physical solvent (triethylene glycol) in specific ratios. This composite approach leverages the CO2-reactive properties of MEA and the low-volatility, heat-reducing properties of TEG to achieve both high absorption capacity and reduced energy consumption
2Productivity
If steam is generated in the reboiler to regenerate solvent, then CO2 is released from rich solvent, but additional CO2 emissions are produced and plant output is reduced
Solution Approach 1:
The patent changes the physical-chemical parameters of the solvent system by replacing部分water with triethylene glycol. This parameter change reduces the vaporization temperature and steam generation requirements in the reboiler, thereby reducing CO2 emissions and improving overall plant productivity
3Loss of energy
If cross exchanger is used to exchange heat from lean solvent to rich solvent, then energy efficiency is improved, but heat losses still occur
Solution Approach 1:
The patent changes the thermal parameters of the solvent system through the addition of triethylene glycol, which has different heat capacity and thermal conductivity properties compared to water. This parameter change reduces the overall heat loss in the system, making the cross-exchanger more effective and reducing the need for additional heat exchange equipment
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 reduces the total heat rate by 10-15% by minimizing steam generation and heat losses, improving carbon dioxide absorption capacity and overall energy consumption while maintaining a non-corrosive and stable solvent mixture.
Implementation Method 1
an aqueous chemical solvent (typically an aqueous solution of MEA, AMP, and/or piperazine) is utilized in an absorber to absorb CO2 in the form of chemical complexes with the solvent species and water
Implementation Method 2
A stripper is utilized to release CO2 from the rich solvent through the application of heat, to produce a lean solvent
Implementation Method 3
applying heat to the rich solvent system using the reboiler, generating a vapor stream within the reboiler
Implementation Method 4
In such processes a cross exchanger is utilized to improve efficiency by exchanging heat from the lean solvent into the rich solvent
Implementation Method 5
transferring the vapor stream to a condenser
Data Source
AI summary
A system for carbon dioxide capture from a gas mixture comprises an absorber that receives a lean solvent system stream (containing a chemical solvent, physical-solvent, and water) from the stripper, a stripper that receives the rich solvent stream from the absorber and produces the product carbon dioxide and the lean solvent through the use of a reboiler in fluid communication with a lower portion of the stripper, a condenser in fluid communication with a vapor outlet of the stripper, a cross-exchanger in fluid communication with a rich solvent system outlet from the absorber and a rich solvent system inlet on the stripper, and a splitter. The splitter is configured to separate the rich solvent system stream into a first portion and second portion, where the first portion directly passes to the stripper and the second portion passes through the cross-exchanger prior to passing to the stripper.