Hybrid membrane distillation system for energy-efficient ethylene/ethane separation

Title : Hybrid membrane distillation system for energy-efficient ethylene/ethane separation

Abstract:

The conventional technique for separating close-boiling-point systems is highly energy-intensive. A hybrid membrane distillation system (HMD) is an alternative approach for reducing energy consumption and increasing separation efficiency. However, the simulation, design, and optimization of HMD are highly challenging due to the high complexity and interaction between the separation units and the associated utility systems.

This study presents a systematic framework for evaluating membrane-assisted distillation separation systems. MATLAB, integrated with Aspen HYSYS, is used to design, simulate, and optimize hybrid membrane–distillation configurations, enabling both preliminary design and parametric analysis. The approach combines membrane cross-flow modeling with Fenske–Underwood–Gilliland (FUG) shortcut methods for distillation design, while operating conditions and membrane placement are optimized via nonlinear programming to minimize total operating cost.

A case study on ethylene/ethane separation using a facilitated transport membrane demonstrates the effectiveness of the framework. The membrane has an ethylene permeability of 0.3×10⁻¹⁴ mol.m.s⁻¹·m⁻².Pa⁻¹, and a membrane selectivity of 54. The feed flow rate is assumed to be 100 kmol·h⁻¹ with a composition of 54 mol% C₂H₄ and 46 mol% C₂H₆. The distillation column operates at 20 bar, and the reflux ratio is fixed at 1.05 times the minimum reflux ratio (R/Rmin).

The results highlight the potential of hybrid configurations to enhance separation performance while reducing energy consumption and operating costs, achieving high ethylene purity (99.9 mol%). The optimization results show that the parallel hybrid scheme is the best option, reducing the condenser duty by approximately 33% compared to a conventional distillation column. Additionally, the parallel hybrid scheme reduces the total operating cost by 28%, while the sequential hybrid scheme achieves a 14% reduction. In conclusion, the integration of hybrid membrane–distillation with advanced modeling and optimization presents a promising, energy-efficient, and cost-effective alternative for the separation of light hydrocarbon mixtures.

Biography:

Dr. Assma Etoumi is a Senior Specialist in the Process Engineering Department at PRC and holds a PhD in Chemical Engineering from the University of Manchester. Dr. Etoumi has extensive experience in petroleum and process engineering, with specialized expertise in the modeling of refrigeration systems, evaluation and assessment of asphaltene and wax behavior in crude oil, and advanced hybrid process modeling and optimisation. Her research interests focus on the application of innovative methodologies to address complex engineering challenges, enhance operational performance, and promote sustainability within the oil and gas sector.