DefinePK

Research Objective

To optimize the parameters and characterize the products obtained from CO2 capture using ammonium bicarbonate in a lab-scale stripping batch process, focusing on ammonia recovery and CO2 capture.

Methodology

A lab-scale experimental setup was used, involving bubbling pure CO2 gas through aqueous ammonium hydroxide solutions of varying concentrations (5%, 10%, 15%) at temperatures below 5°C. The experiment varied absorption times (60, 90, 120, 140 minutes) and CO2 flow rates (0.2, 0.3, 0.4, 0.5 L/min). The precipitated product was analyzed using Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), FTIR, and pH measurements.

Methodology Flowchart

                        graph TD;
    A[Prepare NH4OH Solution] --> B[Bubble CO2 Gas];
    B --> C[React and Precipitate];
    C --> D[Analyze Precipitated Product];
    D --> E[Characterize Product];
    E --> F[Record Data];
    F --> G[Optimize Parameters];
    G --> H[Formulate Conclusion];                    

Discussion

The study highlights the effectiveness of aqueous ammonia in capturing CO2 and producing ammonium bicarbonate. The findings on the effect of time and CO2 flow rate align with previous research, indicating that higher flow rates enhance absorption. The research also clarifies the relationship between NH4OH concentration, pH, and precipitation time, suggesting that while higher concentrations yield more product, they necessitate longer reaction times to reach the optimal pH range for precipitation. The characterization techniques confirmed the formation of ammonium bicarbonate, a valuable byproduct.

Key Findings

- The optimal conditions for maximizing ammonium bicarbonate (NHHCO3) production were found to be 110 minutes of absorption time, a CO2 gas flow rate of 0.5 L/min, and a 15% NH4OH solution.
- Product quantity increases with reaction time up to approximately 110 minutes, after which it plateaus.
- Higher CO2 flow rates lead to increased product formation.
- Higher concentrations of NH4OH solutions (specifically 15%) result in increased product quantity, although they require more time to precipitate due to higher initial pH.
- The precipitated product was confirmed to be ammonium bicarbonate (NHHCO3) and ammonium carbonate (NHCO3) through XRD, FTIR, and microscopic analysis.

Conclusion

The lab-scale stripping batch process is effective for capturing CO2 and recovering ammonia by producing ammonium bicarbonate. The study identified optimal parameters for maximizing product yield and confirmed the identity of the produced compounds. The research suggests that this method has potential for industrial implementation in sectors with CO2 and NH3 emissions.

Fact Check

- The optimal absorption time for maximizing NHHCO3 production was identified as 110 minutes.
- The optimal CO2 gas flow rate for maximizing NHHCO3 production was identified as 0.5 L/min.
- The optimal NH4OH solution concentration for maximizing NHHCO3 production was identified as 15%.

Mind Map