A study of a novel membrane-based liquid-gas contactor

Abstract

Two dual-membrane configurations were conceptually proposed to improve the performance of the ordinary single-membrane contactor. In Configuration 1, a second porous membrane was added and a flow of sweeping gas was introduced on the permeate side of the second membrane; in Configuration 2, the second membrane was a nonporous one, and a low pressure was applied on the permeate side of the nonporous membrane. Theoretically both configurations can partially regenerate the solvent stream simultaneously with the absorption process. Since the rate of acid gas absorption is a function of the concentration of acid components in the solvent, by continuous removal of these components from the solvent, a better absorption efficiency can be obtained. The new ideas were first simulated using partial differential equations and corresponding initial and boundary conditions based on one-component absorption, and the Crank-Nicholson method was used to obtain the numerical solutions. The solutions showed that the novel dual-membrane contactors can remove acid components more efficiently than the ordinary membrane contactor. Based on a single-component absorption simulation, analyses were carried out to examine the effects of a variety of parameters on the removal efficiency. In addition, the mathematic model for multi-component system in which more than one component participated in absorption was developed and solved to simulate acid gas removal in natural gas handling.