Modeling of Nanofiltration Process Using DSPM-DE Model for Purification of Amine Solution

Area of Science:

• Chemical Engineering
• Separation Processes
• Environmental Science

Background:

• Heat stable salts (HSS) formation in natural gas sweetening using amine solvents leads to operational problems like corrosion and reduced efficiency.
• Amine solvent degradation necessitates costly replacement and impacts the overall economic viability of gas sweetening processes.

Purpose of the Study:

• To develop and validate a nanofiltration (NF) model for removing heat stable salts (HSS) from methyl di-ethanol amine solutions.
• To investigate the impact of membrane characteristics and operating conditions on HSS removal efficiency and amine solution recovery.

Main Methods:

• A mathematical model was developed to simulate the nanofiltration process, incorporating parameters like pore radius and membrane charge.
• Experimental data was used to correlate feed and permeate concentrations (C_i,p = f (C_i,f)) for model validation.
• The study analyzed the influence of operating conditions, including feed pressure and flow rate, on ion rejection and recovery ratios.

Main Results:

• The developed model demonstrated good agreement with experimental results, achieving a coefficient of determination (R²) between 0.75 and 0.90.
• Nanofiltration effectively removed ternary ions from the methyl di-ethanol amine solution.
• Ion rejection and recovery ratios were found to be dependent on the driving pressure, which is influenced by feed flow and pressure.

Conclusions:

• Nanofiltration is a viable technology for removing heat stable salts (HSS) from amine solutions, facilitating solvent reuse in natural gas sweetening.
• The developed model provides a valuable tool for optimizing NF process parameters to enhance HSS removal and maximize amine recovery.
• Understanding the relationship between operating conditions and membrane performance is crucial for efficient and sustainable gas sweetening operations.