Simulation of Hydrogen Production from Crude Glycerol Using Steam Reforming

Abstract

The rising global production of biodiesel has led to a surplus of crude glycerol, a byproduct accounting for about 10% of biodiesel’s weight. Crude glycerol contains various impurities, including unreacted alcohol, soap, free fatty acids, water, and leftover reagents, which are often considered waste. Several methods have been explored to utilise this surplus, such as combustion for energy recovery, composting, animal feed, and purification. However, purification can be expensive and is often not economically viable. While there is growing interest in hydrogen production via the steam reforming of glycerol, there is a significant lack of detailed information and research on simulating this process using ChemCAD 8.1.0 software. This study aimed to simulate glycerol steam reforming (GSR) using ChemCAD, a process that converts crude glycerol from biodiesel into hydrogen. The process operates on a Gibbs free energy reactor, simulating GSR using the UNIFAC thermodynamic model under various conditions: temperatures ranging from 200 °C to 1000 °C, steam-to-glycerol mass ratios from 2:1 to 12:1, and a nickel catalyst maintained at 1 wt.%. The results demonstrate maximum glycerol consumption at temperatures above 600 °C and at a steam-to-glycerol mass ratio of 6:1. The optimum conditions for achieving a hydrogen yield of 65.23% occur at 800 °C and a ratio of 8:1 while minimising the formation of byproducts such as CO2, CO, and CH4. These findings provide valuable insights for optimising GSR processes and promoting the sustainable utilisation of renewable energy sources, thereby contributing to the circular economy and supporting the United Nations Sustainable Development Goal 7 (Affordable and Clean Energy).