Application of Aspen HYSYS for Predicting the Effects of Impurities on Thermodynamic Performance of Glycerol Autothermal Reforming for Hydrogen Production

Sarafadeen Ayinde Azeez ,Usman Garba ,B G Danshehu

doi:10.5829/ijee.2020.11.01.08

Sarafadeen Ayinde Azeez , Usman Garba + Show 1 more

Open Access

https://doi.org/10.5829/ijee.2020.11.01.08

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Abstract

Hydrogen production from glycerol via autothermal reforming (ATR) has been widely investigated. However, little is known about the influence of impurities in glycerol on thermodynamic performance of the process. This study focused on the effects of impurities in glycerol on hydrogen productivity, energetic and exergetic efficiencies. The model of the entire process was simulated under thermoneutral condition in Aspen HYSYS using pure glycerol (PG) and crude glycerol (CG) as feeds. The two cases were optimized for maximum hydrogen production. From the optimized results, the hydrogen production per mole of the feed was 4.937 and 6.160 for the case of PG and CG, respectively. The thermal and exergetic efficiency of PG as feed were computed as 79.51% and 57.04% while that of CG were obtained to be 77.7 and 54.08%, respectively. The exergy destroyed to produce 1 mole of H2 was found to be 133.5kJ and 157.3kJ for the case of PG and CG, respectively. It could be concluded that the presence of other constituents in CG contributed to increase in hydrogen productivity by increasing the energy demand of the plant but due to increase in both energy and exergy input, they decrease both the thermal and exergetic efficiencies.

Highlights

The continuous release of greenhouse gases into the atmosphere and sudden change in climate conditions causing detrimental effect on our environment accounted for growing research in finding energy source that can replace fossil fuels
Most of the works carried out in this field is concentrated on evaluation of thermodynamic performance of pure glycerol autothermal reforming (ATR) reactor and/or catalysis in the system, but energetic and exergetic assessment of the entire process of hydrogen production from crude glycerol through ATR is very scarce in literature
Simulation results The components molar flow rate of effluents from reformer and PSA using pure glycerol (PG) and crude glycerol (CG) as feeds are presented in Table 2. 346.786 kgmole/h of hydrogen was obtained from PG which was later increased by 40% via shift and partial oxidation reactions installed for CO clean-up process

Summary

Introduction

The continuous release of greenhouse gases into the atmosphere and sudden change in climate conditions causing detrimental effect on our environment accounted for growing research in finding energy source that can replace fossil fuels. The reforming technology considered for simulation in this study was autothermal reforming due to its energy efficiency and process stability For these reasons, many works have been centered on improving hydrogen productivity in ATR of glycerol. Hajjaji et al [16] studied the process simulation of production of hydrogen via autothermal reforming of PG They obtained 78.7 and 67.8% as the optimum thermal and exergetic efficiencies, respectively. This research work is aimed to determine the effect of impurities in crude glycerol on thermal efficiency, exergetic efficiency and hydrogen productivity of glycerol autothermal reforming process This was achieved by modeling and thermodynamic analysis of an optimized system of hydrogen production from both PG and CG through autothermal reforming

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