Mania Abdollahi-Neisiani, Jean-Philippe Laviolette, Rouzbeh Jafari and Jamal Chaouki

Abstract Bioreflnery is the object of significant research and development efforts due to the scarcity of economically viable crude oil, renewable energy source, and its environmental benefits. This has prompted chemical corpo-rations to look for alternative sources of carbon and hydrogen to produce chemicals, biologics, and other products such as biomass and waste matter. Two main reaction pathways are currently explored for biorefinery: thermochemical and biochemical. The thermo­chemical pathway proposes significantly higher reaction rates compared to current biological processes that use non-genetically modified organisms. One of the thermo­chemical pathways for biomass conversion is gasification which is a decomposition of solid fuels at high temperatures and oxygen-lean atmosphere. The successful development of biomass gasification processes requires addressing several critical technical difficulties including biomass diversity, feedstock treatment, gasification mechanism and reactions, gasifier types, and their performances. This chapter re­views key features of biomass gasification as a pretreatment for biorefining which can be used as a practical guide for gasification process. This chapter consists of six sections that include types of biomass for gasification, their properties, and pretreat­ment steps; gasification mechanism and reactions; syngas cleaning and conditioning; different gasifier, their characteristics, and modeling.

Keywords Biomass gasification ■ Pretreatment ■ Gasifier ■ Gas cleaning ■ Tar removal ■ Catalytic gasification

J. Chaouki (H) ■ M. Abdollahi-Neisiani ■ J.-P. Laviolette ■ R. Jafari Department of Chemical Engineering, Ecole Polytechnique de Montreal, C. P. 6079, succ. Centre Ville, Montreal, H3C 3A7, Canada e-mail: jamal. chaouki@polymtl. ca

M. Abdollahi-Neisiani

e-mail: mania. abdollahineisiani@polymtl. ca

J.-P. Laviolette

e-mail: jean-philippe. laviolette@polymtl. ca R. Jafari

e-mail: rouzbeh. jafari@polymtl. ca

Z. Fang (ed.), Pretreatment Techniques for Biofuels and Biorefineries,

Green Energy and Technology,

DOI 10.1007/978-3-642-32735-3_10, © Springer-Verlag Berlin Heidelberg 2013

10.1 Introduction

The beginning of industrial civilization has triggered the frantic use of non-renewable fossil-fuel resources (coal first, followed by oil and gas), which has grown worldwide ever since. Today, the price of fossil fuels is increasing due to depleting “conven­tional” resources, rising demands from developing countries and the establishment of a low-carbon economy. In this context, significant investments and research are focusing on the development of new processes to extract energy and goods from renewable resources, such as biomass.

Biomass is a carbonaceous matter, known as a renewable energy source from living or recently living organisms. Examples include forest residue, agricultural wastes, and even, municipal solid waste. To convert biomass, two main reaction pathways are currently considered: biochemical and thermochemical. Gasification is a thermo-chemical pathway, which transfers the combustion value of the solid fuel to the gas phase whose composition maximizes its chemical energy rather than sensible heat. Syngas, a mixture of CO and H2, is one of the products of the gasification process, which could be used as a fuel or building block for many hydrocarbons. The products derived from syngas can be divided into three categories: (1) chemicals, such as ammonia and methanol; (2) transportation fuels, such as synthetic natural gas and synthetic diesel; (3) and energy feedstock, such as methane. Currently, syngas is produced mainly from fossil fuels; however, there is a growing interest in generating “green chemicals” and “green fuels” from the gasification process.

To successfully design an industrial gasification process, a thorough knowledge of biomass pretreatment, gasification reaction kinetics, and reactor technologies is essential. This chapter discusses the subject of biomass gasification through a detailed review of the scientific and industrial literature.