Green Hydrogen Production from Raw Biogas: A Techno-Economic Investigation of Conventional Processes Using Pressure Swing Adsorption Unit

Gioele Marcoberardino,Giampaolo Manzolini,Marco Binotti,Francesco Spinelli,Dario Vitali

doi:10.3390/pr6030019

Gioele Marcoberardino, Giampaolo Manzolini + Show 3 more

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https://doi.org/10.3390/pr6030019

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Journal: Processes	Publication Date: Feb 25, 2018
Citations: 78	License type: CC BY 4.0

Affiliation: Politecnico di Milano

Abstract

This paper discusses the techno-economic assessment of hydrogen production from biogas with conventional systems. The work is part of the European project BIONICO, whose purpose is to develop and test a membrane reactor (MR) for hydrogen production from biogas. Within the BIONICO project, steam reforming (SR) and autothermal reforming (ATR), have been identified as well-known technologies for hydrogen production from biogas. Two biogases were examined: one produced by landfill and the other one by anaerobic digester. The purification unit required in the conventional plants has been studied and modeled in detail, using Aspen Adsorption. A pressure swing adsorption system (PSA) with two and four beds and a vacuum PSA (VPSA) made of four beds are compared. VPSA operates at sub-atmospheric pressure, thus increasing the recovery: results of the simulations show that the performances strongly depend on the design choices and on the gas feeding the purification unit. The best purity and recovery values were obtained with the VPSA system, which achieves a recovery between 50% and 60% at a vacuum pressure of 0.1 bar and a hydrogen purity of 99.999%. The SR and ATR plants were designed in Aspen Plus, integrating the studied VPSA model, and analyzing the behavior of the systems at the variation of the pressure and the type of input biogas. The SR system achieves a maximum efficiency, calculated on the LHV, of 52% at 12 bar, while the ATR of 28% at 18 bar. The economic analysis determined a hydrogen production cost of around 5 €/kg of hydrogen for the SR case.

Highlights

The current challenges of energy saving and reduction of CO2 emissions must deal with the significant growth of energy demand
The global hydrogen production is nowadays within the range of 600–720 billion Nm3 /year, 80 billion of which is produced in the European Union [1], and it is continuously increasing at a rate of 5–6% per year
Almost 50% of the global hydrogen production is currently generated via steam methane reforming (SR), using natural gas (NG) as feedstock, while less than 3–4% is produced without using fossil fuels [2]

Summary

Introduction

The current challenges of energy saving and reduction of CO2 emissions must deal with the significant growth of energy demand. Hydrogen is a promising energy carrier that can replace fossil fuels in power generation and transportation, drastically reducing local pollution and CO2 emission when produced by renewable sources. The global hydrogen production is nowadays within the range of 600–720 billion Nm3 /year, 80 billion of which is produced in the European Union [1], and it is continuously increasing at a rate of 5–6% per year. Almost 50% of the global hydrogen production is currently generated via steam methane reforming (SR), using natural gas (NG) as feedstock, while less than 3–4% is produced without using fossil fuels [2]. Hydrogen production is still bounded to non-renewable sources. Conventional plants lead to large CO2 emissions to the atmosphere (about 380–420 kgCO2 /Nm3 H2 ), associated with the combustion of off-gas and of the additional fuel required to provide heat for the endothermic reforming reactions

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