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Hedayat, Mahdi | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41722 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Soltanieh, Mohammad; Seifkordi, Ali Akbar
  7. Abstract:
  8. Using membrane contactors for acid gas removal, combines the advantages of membrane based separation processes and traditional ones. In this project we aim to study the use of a membrane absorption system for sweetening gas streams containing mixed acid gases with composition similar to raw natural gas. H2S and CO2 exist in the gas stream simultaneously which can be removed by mixture of alkanolamine solvents, including MDEA, DEA and MEA, are used for treating. A lab-scale membrane absorption setup with feed capacity of 2 lit/min, was designed, constructed and commissioned. Several hollow fiber modules equipped with PSf and PVDF membranes were fabricated. Our results revealed that reaching high removal efficiency of H2S is possible. Both membranes were wetted by the solvent, but PSf suffers more. Presence of CO2 in feed gas decreases the H2S removal. However, increase of CO2 concentration, has more influence on its removal efficiency. Pressure has positive effect on separation. Temperature increase has negative effect in two component systems, but increases the H2S selectivity in three component systems. Increasing MDEA concentration will accelarate the wetting in two component systems, however, in the presence of CO2 it has a positive effect on removal efficiency, especially on itself. Adding DEA has no important effect. On the other hand, addition of MEA into the solvent will gratefully enhances CO2 removal. The liquid side has no contribution to the overall mass tranfer resistance. In two component systems, gas side has a great resistance, but in three component systems the main resistance is in membrane side, due to aggregation of solute components at the gas-liquid interface. When the goal of the system is high selectivity, using lean MDEA solution is preferred. But when we want to have just high removal efficiencies, it’s better to use MEA-MDEA mixtures as the solvent
  9. Keywords:
  10. Membrane Contactor ; Polymer Membrane ; Wetting ; Membrane Absorption ; Multi-Component Acid Gases ; Alkanolamine Solvents Mixture

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