Ammonia Absorption CO2 Removal Process
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Solution Overview
Problem
Existing CO2 removal systems using ammonia solutions face inefficiencies due to high energy consumption, costly high-pressure designs, and contamination issues when handling stripper offgas streams, which contain ammonia, CO2, and non-condensable contaminants.
Innovation Solution
A method involving a three-stage gas-liquid mass transfer process using ammonia solutions, where CO2 is absorbed in a first stage, ammonia is absorbed and separated in a second stage, and then reabsorbed in a third stage, allowing for efficient recycling and reducing the burden on the CO2 absorption process by using low-pressure steam and separate mass transfer devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ammonia is removed from the gas in a wash step by scrubbing with wash liquid, then residual ammonia is removed from the treated gas, but the wash liquid contains absorbed ammonia that requires additional stripping process and energy consumption
Solution Approach 1:
The patent combines the CO2 absorption and NH3 removal functions into a single absorption liquid circulation system. The absorption liquid performs both CO2 absorption and NH3 removal simultaneously, eliminating the need for separate wash and stripping processes, thereby reducing energy consumption while effectively removing residual ammonia from the treated gas
Solution Approach 2:
The absorption liquid is designed to perform multiple functions: absorbing CO2 from the gas stream, removing residual NH3 through circulation, and being regenerated in situ. This multi-functional approach eliminates the need for separate wash liquid systems and reduces the overall energy requirement for gas treatment
2Quantity of substance
If the stripper offgas stream is discharged to the atmosphere or introduced into a regenerator unit, then ammonia is separated from the wash liquid, but CO2 is separated and removed requiring additional equipment and operational complexity
Solution Approach 1:
The patent extracts and removes the need for separate regenerator units and complex offgas handling systems. By using a circulation-based absorption liquid system, ammonia separation occurs naturally through the circulation and regeneration process, eliminating the need for additional separation equipment and simplifying the overall process design
Solution Approach 2:
The absorption liquid system is self-regenerating through circulation. The liquid absorbs CO2 and NH3, then regenerates in situ by releasing the absorbed gases, and circulates back to repeat the process. This self-service mechanism eliminates the need for external regenerator units and complex offgas treatment equipment
3Productivity
If high-pressure designs are used for CO2 removal systems, then CO2 absorption efficiency is improved, but the cost and complexity of the system increases
Solution Approach 1:
The patent changes the operational parameters from high-pressure to atmospheric or near-atmospheric pressure conditions. By optimizing the absorption liquid composition and circulation rate, the system achieves effective CO2 removal at lower pressures, significantly reducing equipment cost and complexity while maintaining high removal 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 enhances CO2 removal efficiency, reduces energy consumption, and minimizes contamination in the CO2 product stream by utilizing low-pressure steam and separate mass transfer devices, making the process more economical and environmentally friendly.
Implementation Method 1
contacting a flue gas stream comprising CO2 with a first absorption liquid comprising NH3 such that the flue gas stream is depleted in CO2
Implementation Method 2
contacting the flue gas stream depleted in CO2 of step a) with a second absorption liquid such that NH3 from the flue gas stream is absorbed in said second absorption liquid
Implementation Method 3
separating NH3 from the second absorption liquid such that a gas stream comprising NH3 is obtained
Implementation Method 4
contacting said gas stream comprising NH3 separated in step c) with a third absorption liquid such that NH3 is absorbed in said third absorption liquid
Data Source
Figure 1
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AI summary
A method for removal of CO2 from a flue gas stream, comprising the steps of : a) contacting (101) a flue gas stream comprising CO2 (102) with a first absorption liquid comprising NH3 (103) such that the flue gas stream is depleted in CO2; b) contacting (106) the flue gas stream depleted in CO2 (105) of step a) with a second absorption liquid (107) such that NH3 from the flue gas stream is absorbed in said second absorption liquid to form a flue gas stream depleted in CO2 and NH3 (109); c) separating (110) NH3 from the second absorption liquid such that a gas stream comprising NH3 (114) is obtained; d) contacting (113) said gas stream comprising NH3 separated in step c) with a third absorption liquid (115) such that NH3 is absorbed in said third absorption liquid. A system for removal of CO2 from a flue gas stream, the system comprising: a CO2 absorption stage; an NH3 absorption stage; and a reabsorption stage.