Process parametric testing and simulation of carbon membranes for H2 recovery from natural gas pipeline networks

Abstract

The construction of H2 infrastructure is crucial for accomplishing an H2 economy in the future, however, the current cost of H2 transportation is relatively expensive due to the lack of infrastructure. One of the alternatives is to inject H2 into the existing natural gas pipeline networks, which is subsequently recovered by membrane technology for end-users. In this work, the high-performance cellulose-derived asymmetric carbon hollow fiber membrane developed in previous work was tested for H2/CH4 separation. The experimental results demonstrated the outstanding separation performance and good stability of the developed carbon membrane with H2 permeance of up to 21.3 GPU and H2/CH4 separation factor of up to 96 at 50 ℃ under different feed pressures of 5–40 bar and H2 concentrations of 5–25 vol%. The techno-economic feasibility analysis for H2 recovery from the natural gas pipeline networks was conducted. A two-stage carbon membrane system was designed to produce high-purity H2 (>99.7 vol%) by UniSim simulation. Notably, the higher 1st-stage feed pressure (8–40 bar) and the higher feed H2 content (5–25 vol%) significantly lessened the required membrane areas, contributing to reducing the major expense on H2 recovery cost. Moreover, the influences of the process operating factors (e.g., feed H2 content, feed pressure, etc.) on H2 recovery cost were systematically explored, and the results indicated the considerable impact of process design on H2 recovery cost.