Tailoring the Stabilization and Pyrolysis Processes of Carbon Molecular Sieve Membrane Derived from Polyacrylonitrile for Ethylene/Ethane Separation

For ethylene/ethane separation, a CMS (carbon molecular sieve) membrane was developed with a PAN (polyacrylonitrile) polymer precursor on an alumina support. To provide an excellent thermal property to PAN precursor prior to the pyrolysis, the stabilization as a pre-treatment process was carried out. Tuning the stabilization condition was very important to successfully preparing the CMS membrane derived from the PAN precursor. The stabilization and pyrolysis processes for the PAN precursor were finely tuned, and optimized in terms of stabilization temperature and time, as well as pyrolysis temperature, heating rate, and soaking time. The PAN stabilized at >250 °C showed improved thermal stability and carbon yield. The CMS membrane derived from stabilized PAN showed reasonable separation performance for ethylene permeance (0.71 GPU) and ethylene/ethane selectivity (7.62), respectively. Increasing the pyrolysis temperature and soaking time gave rise to an increase in the gas permeance, and a reduction in the membrane selectivity. This trend was opposite to that for the CMS membranes derived from other polymer precursors. The optimized separation performance (ethylene permeance of 2.97 GPU and ethylene/ethane selectivity of 7.25) could be achieved at the pyrolysis temperature of 650 °C with a soaking time of 1 h. The separation performance of the CMS membrane derived from the PAN precursor was comparable to that of other polymer precursors, and surpassed them regarding the upper bound trade off.

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Carbon Molecular Sieve Membranes from Polyetherimide: Effect of Pyrolysis Temperature on O2/N2 Selectivity

Journal of Applied Membrane Science & Technology ◽

10.11113/amst.v14i1.96 ◽

2017 ◽

Vol 14 (1) ◽

Author(s):

M. A. Ahmad ◽

N. K. A. Rashid ◽

B. H. Hameed

Keyword(s):

Molecular Sieve ◽

Pyrolysis Temperature ◽

Gas Permeability ◽

High Surface ◽

High Surface Area ◽

Carbon Layer ◽

Separation Performance ◽

Carbon Molecular Sieve ◽

Carbon Structures ◽

Thin Carbon

Carbon molecular sieve (CMS) membranes with excellent separation performance and stability appear to be promising candidate for gas separation. In this work, CMS membranes were formed by a thin carbon layer obtained by pyrolysis of a coated polyetherimide solution onto porous disk support. The pyrolysis temperatures were varied under inert condition. Results showed that the pyrolysis temperature played an important role in determining the gas permeability of CMS membranes. The CMS membrane prepared at pyrolysis temperature of 700°C shows high surface area and narrow PSD with well developed microporous carbon structures. The development of large pore occurs at higher pyrolysis temperature. The O2/N2 permselectivities of 2.86, 2.61 and 2.22, respectively were attained by CMS membranes prepared at pyrolyzed temperature of 700, 800 and 900°C.

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A Mini Review on Carbon Molecular Sieve Membrane for Oxygen Separation

Journal of Modern Manufacturing Systems and Technology ◽

10.15282/jmmst.v4i1.3800 ◽

2020 ◽

Vol 4 (1) ◽

pp. 23-35

Author(s):

Fatin Nurwahdah Ahmad ◽

Norazlianie Sazali ◽

Mohd Hafiz Dzafran Othman

Keyword(s):

Molecular Sieve ◽

High Performance ◽

Separation Performance ◽

Carbon Membrane ◽

Carbon Molecular Sieve ◽

Carbon Membranes ◽

Advantages And Disadvantages ◽

Polymer Precursors ◽

And Performance

Membrane-based technology has proved its practicality in gas separation through its performance. Various type of membranes has been explored, showing that each type of them have their own advantages and disadvantages. Polymeric membranes have been widely used to separate O2/N2, however, its drawbacks lead to the development of carbon molecular sieve membrane. Carbon molecular sieve membranes have demonstrated excellent separation performance for almost similar kinetic diameter molecules such as O2/N2. Many polymer precursors can be used to produce carbon molecular sieve membrane through carbonization process or also known as heat treatment. This paper discusses the variety of precursors and carbonization parameters to produce high quality and performance of carbon molecular sieve membranes. This paper covers the evaluation in advancement and status of high-performance carbon membrane implemented for separating gas, comprising the variety of precursor materials and the fabrication process that involve many different parameters, also analysis of carbon membranes properties in separating various type of gas having high demand in the industries. The issues regarding the current challenges in developing carbon membrane and approaches with the purpose of solving and improving the performance and applications of carbon membrane are included in this paper. Also, the advantages of the carbon membrane compared to other types of membranes are highlighted. Observation and understanding the variables affecting the quality of membrane encourage the optimization of conditions and techniques in producing high-performance membrane.

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Effect of polymer precursors on carbon molecular sieve structure and separation performance properties

Carbon ◽

10.1016/j.carbon.2010.08.002 ◽

2010 ◽

Vol 48 (15) ◽

pp. 4432-4441 ◽

Cited By ~ 71

Author(s):

Mayumi Kiyono ◽

Paul J. Williams ◽

William J. Koros

Keyword(s):

Molecular Sieve ◽

Separation Performance ◽

Carbon Molecular Sieve ◽

Performance Properties ◽

Polymer Precursors

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Enhanced Performance of Carbon Molecular Sieve Membranes Incorporating Zeolite Nanocrystals for Air Separation

Membranes ◽

10.3390/membranes11070489 ◽

2021 ◽

Vol 11 (7) ◽

pp. 489

Author(s):

Chong Yang Chuah ◽

Kunli Goh ◽

Tae-Hyun Bae

Keyword(s):

Polymer Matrix ◽

Upper Bound ◽

Molecular Sieve ◽

Gas Permeation ◽

Separation Process ◽

Air Separation ◽

Separation Performance ◽

Mixed Matrix ◽

Carbon Molecular Sieve ◽

Polymer Precursors

Three different zeolite nanocrystals (SAPO-34, PS-MFI and ETS-10) were incorporated into the polymer matrix (Matrimid® 5218) as polymer precursors, with the aim of fabricating mixed-matrix carbon molecular sieve membranes (CMSMs). These membranes are investigated for their potential for air separation process. Based on our gas permeation results, incorporating porous materials is feasible to improve O2 permeability, owing to the creation of additional porosities in the resulting mixed-matrix CMSMs. Owing to this, the performance of the CMSM with 30 wt% PS-MFI loading is able to surpass the upper bound limit. This study demonstrates the feasibility of zeolite nanocrystals in improving O2/N2 separation performance in CMSMs.

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