Meet the editors

Valter Silva is a senior researcher in the area of environment and energy at the Portuguese Collaborative Laboratory for Integrated Forest & Fire Management and Senior Collaborator Researcher at the Polytechnic Institute of Portalegre, Portugal He graduated in Chemical Engineering from the University of Porto, Portugal, in 2004, obtained his Ph.D. in Chemical and Biological Engineering at the same university in 2009, and his degree as

Specialist in Numerical Simulation (combustion and fluid dynamics) at Technical University of Madrid and Ansys, Inc., in 2017. Since 2012, he has led a research team devoted to the application of experimental and numerical solutions on the environment and energy topics (gasification, combustion, fuel cells, techno-economic analysis, LCA, CFD, and optimization). In the last five years, he coordinated national and international projects with leading universities across the world (e.g., MIT and Carnegie Mellon) raising approximately \$2.5 million in funds. He has supervised more than thirty students (postdoc, Ph.D., master, and diploma students). He has participated in more than twenty-five national and international projects in energy and environment and has authored two books, eleven book chapters, and more than sixty papers in international peer-reviewed journals.

Celso Eduardo Tuna is a mechanical engineer who graduated from the São Paulo State University (UNESP), Brazil, in 1989. He obtained a master's degree and Ph.D. in Mechanical Engineering from UNESP, where he is also an associate professor, in 1995 and 1999, respectively. Dr. Tuna is a CNPq research and productivity fellow, professor of the post-graduate course in Mechanical Engineering, and coordinator of the Bioenergy Research Institute

laboratory of UNESP in Guaratinguetá. He has published six book chapters and twenty-eight indexed scientific articles. His research interests include bioenergy, hydrogen generation, renewable energy, and cogeneration.

Contents

**Section 1**

**Section 2**

The Methanol Route

*and Runar Unnthorsson*

Multi-Staged Reactors

*and Soydan Ozcan*

in Brazil and Mexico

*and Luís A.C. Tarelho*

**Preface XI**

Pyrolysis **1**

**Chapter 1 3**

**Chapter 2 43**

**Chapter 3 65**

Gasification **83**

**Chapter 4 85**

**Chapter 5 105**

**Chapter 6 123**

Review Chapter: Waste to Energy through Pyrolysis and Gasification

*Danielle Regina Da Silva Guerra, Daniela Eusébio, João Sousa Cardoso* 

*Georgy Aleksandrovich Sytchev, Vladimir Aleksandrovich Sinelshchikov, Vladimir Aleksandrovich Lavrenov and Olga Mihailovna Larina*

Chemical Carbon and Hydrogen Recycle through Waste Gasification:

*by Alessia Borgogna, Gaetano Iaquaniello, Annarita Salladini,* 

*by Oleg Aleksandrovich Ivanin, Viktor Zaichenko Mikhailovich,* 

Co-Pyrolysis of Biomass Solid Waste and Aquatic Plants

*by José Antonio Mayoral Chavando, Valter Silva,* 

Two-Stage Pyrolytic Conversion of Biomass

*by Md. Emdadul Hoque and Fazlur Rashid*

*Emanuela Agostini and Mirko Boccacci*

Dioxin and Furan Emissions from Gasification *by Seyedeh Masoumeh Safavi, Christiaan Richter* 

Solid Waste Gasification: Comparison of Single- and

*by Xianhui Zhao, Kai Li, Meghan E. Lamm, Serdar Celik, Lin Wei* 

## Contents



Preface

Gasification is the thermochemical process of converting carbonaceous material in the presence of an oxidant less than stoichiometric to form a gaseous product at a high temperature. This gas is known as synthesis gas or syngas. Depending on quality, the gas produced can have different uses, including driving internal combustion engines and gas turbines, direct burning, and synthesis of chemical components.

Gasification transforms a solid material into a gas that can be used as fuel or raw material (methane, ammonia, methanol, gasoline). Different from pyrolysis, which mainly aims to obtain solids and sometimes to obtain liquids, gasification seeks a high production of gases, fundamentally containing CO (10%–20%), H2 (4%–17 %), CH4 (2%–5%), and N2 (40%–60%). This difference in objectives characterizes the operating conditions since gasification operates at temperatures higher than those used in pyrolysis and in the presence of gasifying agents such as water vapor

The main objective of gasification is the conversion of biomass into fuel gas, through its partial oxidation at elevated temperatures. Syngas is an intermediate energy source and can be used later in another conversion process to generate heat or mechanical or electrical power, adapting to systems in which solid biomass cannot be used. This fuel gas has a relatively low calorific value, around 4 to 6 MJ/Nm3

When the biomass enters a gasifier, it first heats up, causing it to dry. Once the temperature is above 400°C, pyrolysis starts, giving rise to a carbon residue (char) formed mainly by carbon and condensable gases (light and heavy hydrocarbons) and non-condensable gases (CH4, water vapor, CO, H2, CO2). When the temperature of the "char" exceeds 700°C, gasification reactions take place, which are divided into heterogeneous (gas-solid) and homogeneous (gas-gas) reactions. This "char" reacts with O2, water vapor, CO2, and H2, and the gases react with each

The result of the process is a gas, whose main constituents are CO, H2, N2, CO2, water vapor, and hydrocarbons or tar (tar). The composition of this gas varies with the characteristics of the biomass, the gasifying agent, and the process conditions. As the C, H, and O reactions for different types of biomass are very similar, the main biomass parameter that influences the gas composition is its moisture content. Thus, with higher moisture content in the biomass, more gasifying agent is needed because the water has to be heated and evaporated. A gas that comes from wet biomass contains relatively large amounts of steam, H2, and N2, compared to dry biomass. For gasification with air, the mixture obtained is a lean gas or gas with a low calorific value (4000 to 6000 kJ/Nm3) since it contains 40 %to 60% N2. The addition of water in the gasifying agent is necessary when one intends to enrich the

gas with H2, producing a gaseous mixture of average calorific value.

Overall, thermochemical gasification takes place inside a reactor, which is classified according to the way in which the reactions are carried out: concurrent or

to force the production of H2 and CO.

(using air as a gasifying agent).

other to produce the final gas mixture.
