Separation Performance of Si-CHA Zeolite Membrane for a Binary H₂/CH₄ Mixture and Ternary and Quaternary Mixtures Containing Impurities

Abstract

The separation of H2/CH4 mixtures is very common in the natural gas and petrochemical industries. There are some higher C2–C4 hydrocarbons and water vapor that are used as impurity gases. Si-CHA zeolite membranes display a high H2 permeance of 1.44 × 10–6 mol/(m2 s Pa) (permeability of 10800 barrers) and H2/CH4 selectivity of 85 for an equimolar H2/CH4 mixture at 298 K and 0.2 MPa pressure drop. A third gas decreased H2 permeance and H2/CH4 selectivity of the membrane. Hydrogen permeance was reduced in an order similar to the adsorption amount in zeolite: H2O > C3H8 > n-butane > ethane. The effects of temperature, pressure, and feed concentration were studied on separation performances of the membrane in the binary and ternary mixtures. A simple model was built up to predict the reduction of permeance and selectivity when multi impurities were contained, and the predicted value agreed well with the tested one. A stable performance was obtained within several hours in all the tests. The separation performance of the membrane was recovered to the original level when the impurity gas was removed.

A Microporous Poly(arylene ether) Platform for Membrane-Based Gas Separation

“…Industrial gas streams often contain impurities such as other small hydrocarbons such as C2H6 . [58][59] Refinery off-gas mixtures usually consist of around 20 mol% of C2 gases, whereas ethylene off-gas mixtures usually consist only trace amount of H2 and C2H6 with a large amount of CH4. 60 To evaluate how C2H6 impurities affect the H2/CH4 separation capability of P5, the gas permeabilities were measured for ternary mixtures of H2/CH4/C2H6 of varying H2 and C2H6 compositions fed at a total pressure of 6.9 bar.…”

Virtual Special Issue of Research Highlights on Sustainable Energy and Clean Fuels at State Key Laboratory of Materials-Oriented Chemical Engineering (SKL-MCE), China

“…Huang et al report a new supramolecular porous material, named NTU-69, which has a one-dimensional (1D) channel with an alternating cage and tube associated with reversible crystal transformation. Activated NTU-69 shows complete C 2 H 2 capture from the C 2 H 2 /C 2 H 4 mixture associated with a high ideal adsorbed solution theory (IAST) selectivity and uptake ratio at 298 K. Wu et al report H 2 /CH 4 separations using a Si-CHA zeolite membrane, which displays high H 2 permeance and H 2 /CH 4 selectivity for an equimolar H 2 /CH 4 mixture at 298 K and 0.2 MPa pressure drop. A third gas decreases the H 2 permeance and H 2 /CH 4 selectivity of the Si-CHA zeolite membrane, and the hydrogen permeance was reduced in an order similar to the adsorption amount in zeolite: H 2 O > C 3 H 8 > n -butane > ethane.…”

A Facile Method to Synthesize b-Oriented Silicalite-1 Thin Film

“…The zeolite thin film/membranes are among inorganic membranes which consist of hydrated crystalline aluminosilicates with open three-dimensional framework structures, made up of SiO 4 and AlO 4 tetrahedrons linked by sharing their oxygen atom to form regular intracrystalline cavities and channels of atomic dimensions. The research of zeolite thin film/membrane is an attractive topic of inorganic membrane technology due to their various applications, such as gas or liquid separation [ 1 , 2 , 3 , 4 , 5 ], chemical sensors [ 6 , 7 , 8 ], catalytic membrane [ 9 , 10 ], dielectric thin films [ 11 , 12 ], corrosion-resistant coatings [ 12 , 13 ] and biological application [ 14 ].…”