Chilled Ammonia Process Control for CO2 Capture
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Solution Overview
Problem
The chilled ammonia process for CO2 capture faces challenges in controlling process conditions, particularly in maintaining a desired mole ratio of ammonia to CO2, which affects CO2 removal efficiency and ammonia slip, especially under short-term or long-term changes in chemical or physical parameters.
Innovation Solution
The process involves controlling the temperature and pressure of the regeneration vessel in the chilled ammonia process to achieve a desired mole ratio of ammonia to CO2 in the CO2 lean ammonia-comprising medium, utilizing a correlation between these parameters to optimize CO2 capture efficiency and minimize ammonia emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the regeneration vessel operates at elevated pressure and temperature to strip CO2 from the ammoniated solution, then CO2 removal efficiency is improved, but ammonia emissions increase
Solution Approach 1:
The patent applies parameter changes by precisely controlling the regeneration pressure and temperature within specific ranges (pressure: 1-30 bar, temperature: 40-150°C) to optimize the stripping process. By adjusting these parameters, the system achieves effective CO2 removal while minimizing ammonia emissions, resolving the contradiction between removal efficiency and emission control
Solution Approach 2:
The patent implements feedback control by continuously monitoring the mole ratio of ammonia to CO2 in the regenerated solution and adjusting the regeneration parameters accordingly. This ensures the solution maintains the desired composition for efficient CO2 absorption while preventing excessive ammonia loss
2Productivity
If the mole ratio of ammonia to CO2 in the CO2 lean ammonia-comprising medium is increased to improve CO2 capture efficiency, then CO2 absorption capacity increases, but ammonia slip increases
Solution Approach 1:
The patent optimizes the mole ratio parameter of ammonia to CO2 in the CO2 lean ammonia-comprising medium within a specific range (0.3-0.7). This parameter optimization allows the system to achieve sufficient CO2 capture efficiency while minimizing ammonia slip, balancing performance and emissions
Solution Approach 2:
The system uses feedback control to monitor and adjust the mole ratio of ammonia to CO2 in real-time based on process conditions. This ensures the optimal balance between CO2 absorption capacity and ammonia emissions is maintained under varying operating conditions
3Manufacturing precision
If the regeneration pressure is increased to produce high purity pressurized CO2 gas stream, then CO2 purity increases, but energy consumption increases
Solution Approach 1:
The patent applies parameter changes by optimizing the regeneration pressure within the range of 1-30 bar to achieve the desired CO2 purity while minimizing energy consumption. The system identifies the optimal pressure point that balances purity requirements with energy 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
This approach allows for precise control of the CO2 capture process, maintaining desired CO2 capture rates with acceptable ammonia emissions, even under varying flue gas flow rates and concentrations, thereby optimizing the overall efficiency and integration with power plants.
Implementation Method 1
contacting in an absorber a flue gas comprising CO2 with a CO2 lean ammonia-comprising medium to absorb CO2 from the flue gas into the CO2 lean ammonia-comprising medium
Implementation Method 2
heating the CO2 rich ammonia-comprising medium to release CO2 from the CO2 rich ammonia-comprising medium
Implementation Method 3
heating the CO2 rich ammonia-comprising medium to release CO2 from the CO2 rich ammonia-comprising medium
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
A process of CO2 removal from a flue gas, comprising: (a) contacting a flue gas with a CO2 lean ammonia-comprising medium to produce a CO2 rich ammonia-comprising medium; (b) heating the CO2 rich ammonia-comprising medium to produce a regenerated CO2 lean ammonia-comprising medium; and (c) supplying the regenerated CO2 lean ammonia-comprising medium to said absorber; (d) identifying a desired mole ratio of ammonia to CO2 of the CO2 lean ammonia-comprising medium; (e) predicting a desired temperature of regenerated CO2 lean ammonia-comprising medium present in a sump of a regeneration vessel or predicting a desired operating pressure of a regeneration vessel; (f) controlling the temperature of regenerated CO2 lean ammonia-comprising medium present in the sump of the regeneration vessel or the operating pressure of the regeneration vessel. A system for removal of CO2 from a flue gas, comprising: i.a. a control unit.