Process Modeling, Optimization, and Heat Integration of Ethanol Reforming Process for Syngas Production with High H2/CO Ratio

Dong Xiang,Xiaoyou Yuan,Peng Li

doi:10.3390/pr7120960

Abstract

The process modeling, parameter optimization, and heat integration of reforming ethanol to hydrogen is conducted in this paper. Modeling results show that the optimum reaction pressure for ethanol steam reforming is 1 bar. When the 7.4:1 is selected as a moderate water/ethanol ratio, the optimum reaction temperature is about 755 °C. As for heat integration, the composite curve and optimum heat-exchange network are given out by pinch technology, of which adding a heat exchanger can reduce 10,833 kW of heating duty and 10,833 kW of cooling duty and make the energy saving reach about 57.4%. Another two heat-integration plans are proposed for the ethanol steam-reforming process, to further decrease the high-level heat duty. Finally, similar heat integration was also carried out for the oxidative steam reforming, and the system is autothermal when the oxygen/ethanol is about 0.5:1 on the basis of above steam-reforming process, while the hydrogen molar purity is decreased from 69% to 66%.

Highlights

Hydrogen has always been considered the most attractive and promising energy carrier, since only water is generated during combustion or oxidation process [1]
The purpose of this study is to establish two options of ethanol reforming, optimize the key operating parameters for the maximum hydrogen production at different H2 /CO ratio, and carry out the energy integration for the whole processes
The optimal reaction temperature is significantly decreased with the increase the equilibrium always moves toward the direction of pressure reduction, i.e., in the negative reaction direction for the ethanol reforming due to its small gas coefficient in the negative reaction

Summary

Introduction

Hydrogen has always been considered the most attractive and promising energy carrier, since only water is generated during combustion or oxidation process [1]. The main hydrogen production methods include water electrolysis, coal and biomass gasification, and reforming [2]. Among them, reforming of hydrocarbons, i.e., natural gas, is the most commonly used process for hydrogen production, owing to its mature technology and economic competitivity [3]. Natural gas is a kind of fossil fuel, and its usage will inevitably lead to a large amount of CO2 emissions caused by heating the steam reformer. The search for renewable feedstock for hydrogen production is urgently needed. Among different biomass-based compounds, ethanol is a promising hydrogen production feedstock for reforming technology because of its relatively high hydrogen content, availability, and storage safety [4]

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Results

Conclusion