Modelling of Landfill Gas Adsorption with Bottom Ash for Utilization of Renewable Energy [Elektronische Ressource] / Chen Miao. Gutachter: Renatus Widmann ; Tim Ricken

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• Publié par: universitat_duisburg-essen
• Publié le: 01 janvier 2011
• Nombre de lectures: 26
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

Modelling of Landfill Gas Adsorption with Bottom Ash
for Utilization of Renewable Energy
Dissertation submitted to the Department of Civil Engineer,
University of Duisburg-Essen
for the degree of “Doktor-Ingenieur” (Dr.-Ing.)
by Chen Miao
born on January 5, 1979 in Jiangsu, P.R. China
Date of examination: 06 October 2011
Reviewer: Prof. Dr.-Ing. Renatus Widmann
Prof. Dr.-Ing. Tim RickenPreface and Acknowledgement
This work is carried out at the ‘Abteilung Siedlungswasser- und Abfallwirtschaft’ of Faculty of
Engineering in Duisburg-Essen University in close cooperation with the ‘Lehrstuhl Mechanik-
Statik-Dynamick’ of Faculty of Architecture and Civil Engineering in TU Dortmund.
I am heartily grateful to my doctoral supervisor Professor Renatus Widmann for supporting me
in terms of development of my scientific and professional skills through my study in Univer-
sity of Duisburg-Essen. I particularly thank the supervisor Professor Tim Ricken of Faculty of
Architecture and Civil Engineering in TU Dortmund. He gives me great support in modelling
development.
This work could never be realized without the opportunity offered by Professor J.-D. Herbell
at Institute of Waste Technology of Duisburg-Essen University, that is my first chance to study
abroad in life. I am thankful for the support of the China Scholarship Council. As a beneficiary
of ‘State-Sponsored Graduate Scholarship Program for Building High-level Universities’, I am
able to give undivided attention to scientific research.
Many thanks belong to my colleagues and every one who gives me advice and help. I particularly
thank Mr. Serdar Serdas and Mr. Daniel Werner. Their warm and friendly cooperation touches
me deeply.
I wish to extend to my personal thanks:
To my beloved family. Thanks for my parents’ great support, their encouragement gives me
intense confidence and passion in study through these years.
I also owe my sincere gratitude to my friends. They give me their time in listening to me and
accompanying me patiently during the difficult course of the thesis.
Chen Miao
Duisburg, Germany
August 2011Summary I
Summary
Energy crisis, environment pollution and climate change are the serious challenges to people
worldwide. In the 21st century, human being is trend to research new technology of renewable
energy, so as to slow down global warming and develop society in an environmentally sustain-
able method.
Landfill gas, produced by biodegradable municipal solid waste in landfill, is a renewable energy
source. In this work, landfill gas utilization for energy generation is introduced. Landfill gas is
able to produce hydrogen by steam reforming reactions. There is a steam reformer equipment in
the fuel cells system. A sewage plant of Cologne in Germany has run the Phosphoric Acid Fuel
Cells power station with biogas for more than 50,000 hours successfully. Landfill gas thus may
be used as fuel for electricity generation via fuel cells system. For the purpose of explaining
the possibility of landfill gas utilization via fuel cells, the thermodynamics of landfill gas steam
reforming are discussed by simulations.
In practice, the methane-riched gas can be obtained by landfill gas purification and upgrading.
This work investigate a new method for upgrading-landfill gas adsorption with bottom ash ex-
perimentally. Bottom ash is a by-product of municipal solid waste incineration, some of its
physical and chemical properties are analysed in this work. The landfill gas adsorption experi-
mental data show bottom ash can be used as a potential adsorbent for landfill gas adsorption to
remove CO . In addition, the alkalinity of bottom ash eluate can be reduced in these adsorption2
processes. Therefore, the interactions between landfill gas and bottom ash can be explained by
series reactions accordingly.
Furthermore, a conceptual model involving landfill gas adsorption with bottom ash is developed.
In this thesis, the parameters of landfill gas adsorption equilibrium equations can be obtained by
fitting experimental data. On the other hand, these functions can be deduced with theoretical
approach. In this thesis, both of them are discussed respectively. Additionally, the diffusion
phenomena of landfill gas mixtures can be expressed by Maxwell-Stefan equations and Fick’s
law. According to the relation between Maxwell-Stefan equations and Fick’s law, the diffusion
coefficients of landfill gas mixtures can be estimated in theory.
The major part of this model is based on the theory of mass transfer through porous media.
In which, mass balance, momentum balance and constitutive relations among multi-phase are
employed for modeling. Landfill gas adsorption processes in two-dimension porous media can
be thus simulated with application of this model.Contents III
Contents
List of Figures VII
List of Tables IX
List of Symbols and Abbreviations X
1 Introduction 1
1.1 Overview and Problem Analysis . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Scope of This Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 Municipal Waste Management 3
2.1 Waste Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1.1 Waste reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1.2 Recycling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1.3 Composting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1.4 Re-use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1.5 Energy recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.6 Landfill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Integrated Waste Management . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2.1 Waste generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.2 Waste pretreatment at source . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.3 Collection and transport . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.4 Processing of solid waste . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.5 Transfer and transport . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.6 Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 Municipal Solid Waste(MSW) . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3.1 Municipal solid waste generation . . . . . . . . . . . . . . . . . . . . 7
2.3.2 Municipal solid waste composition . . . . . . . . . . . . . . . . . . . 9
2.4 Municipal Solid Waste Treatment and Disposal . . . . . . . . . . . . . . . . . 11
2.4.1 MSW treatment in EU . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4.2 MSW treatment in Germany . . . . . . . . . . . . . . . . . . . . . . . 12
2.4.3 MSW treatment in China . . . . . . . . . . . . . . . . . . . . . . . . . 15
3 Landfill Gas Utilization 18
3.1 Landfill Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18IV Contents
3.2 Landfill Gas Utilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.2.1 Overview of landfill gas utilization . . . . . . . . . . . . . . . . . . . . 18
3.2.2 Utilization of landfill gas . . . . . . . . . . . . . . . . . . . . . . . . . 19
4 Utilization of Landfill Gas for Fuel Cells 22
4.1 Fuel Cell Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.1.1 Unit cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.1.2 Cell stack assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.1.3 Processing systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2 Fuel Cell Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2.1 The Nernst equation . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2.2 Thermodynamics of a fuel cell . . . . . . . . . . . . . . . . . . . . . . 25
4.2.3 PAFC analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.3 Landfill Gas Reforming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.3.1 Scope on thermodynamic properties . . . . . . . . . . . . . . . . . . . 31
4.3.2 Steam reforming reactions . . . . . . . . . . . . . . . . . . . . . . . . 34
4.3.3 Simulation results and discussion . . . . . . . . . . . . . . . . . . . . 34
4.4 Conclusion and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5 Landfill Gas Adsorption with Bottom Ash 40
5.1 Municipal Solid Waste Incineration Bottom Ash . . . . . . . . . . . . . . . . . 40
5.1.1 Bulk composition of bottom ash . . . . . . . . . . . . . . . . . . . . . 40
5.1.2 Chemical properties of bottom ash . . . . . . . . . . . . . . . . . . . . 41
5.1.3 Water content and ignition loss . . . . . . . . . . . . . . . . . . . . . . 43
5.1.4 Porosity and pore size distribution . . . . . . . . . . . . . . . . . . . . 44
5.1.5 Heat capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.2 Landfill Gas Adsorption with Bottom Ash . . . . . . . . . . . . . . . . . . . . 46
5.2.1 Fixed bed adsorption processes . . . . . . . . . . . . . . . . . . . . . 46
5.2.2 Adsorption results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
5.3 Landfill Gas Adsorption Equilibrium . . . . . . . . . . . . . . . . . . . . . . . 55
5.4 Interactions Between Landfill Gas and Bottom Ash . . . . . . . . . . . . . . . 57
5.5 Conclusions . . . . . . . . .