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Über dieses Buch

This book provides important insights into the combustion behavior of novel energy crops and agricultural fuels. It describes a new experimental approach to combustion evaluation, involving fundamental, bench-scale and commercial-scale studies. The studies presented were conducted on two representative biomass energy crops: a woody biomass poplar (Populus sp. or poplar) and an herbaceous biomass brassica (Brassica carinata or brassica). Moreover, agricultural residues of Manihot esculenta or cassava were also analyzed. The main accomplishments of this work are threefold. Firstly, it offers an extensive characterization of the above-mentioned fuels, their ash chemistry and their emissions of both solid particles and gaseous compounds that form at typical grate combustion conditions. Secondly, it presents an in-depth analysis of ash fractionation processes for major ash species. Thirdly, it describes the role of some critical and volatile key elements (K, Cl, S and P) in grate-fired combustion systems and elucidates the main differences in the ash chemistry during combustion of Si-rich and P-rich fuels. All in all, this work provides novel insights on the basic and fundamental mechanisms of biomass grate combustion with a special focus on ash transformation and highlights important issues and recommendations that need to be considered for an appropriate conversion of ash-rich fuels and for the development of future technology in the context of both small- and medium-scale biomass-based heat and power production.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract
During the past decade, biofuels, such as stemwood assortments, have been substantially considered to satisfy the increasing European energy market needs based on non-fossil fuels.
Maryori C. Díaz-Ramírez

Chapter 2. Biofuel Characteristics and Grate Conversion

Abstract
Energy crops share many characteristics with other solid fuels, such as coal and wood. Nevertheless, they are clearly differentiated with regard to the fuel chemical properties and, particularly, the ones linked to the inorganic matter.
Maryori C. Díaz-Ramírez

Chapter 3. Research Methodology

Abstract
In this chapter, a description of the research methods applied to gather relevant data needed to fulfill the main objectives of this thesis is presented.
Maryori C. Díaz-Ramírez

Chapter 4. Combustion Performance in a Medium Scale Grate-Fired Unit

Abstract
In the previous chapter, important fuel property differences, particularly with regard to the ash matter characteristics, were identified not only between the two studied species poplar and brassica pellets but also with respect to other species, such as standardized stemwood assortments. In order to achieve more insight on the fuel properties of brassica and poplar energy crop species, knowledge of the grate combustion behavior of these fuels is needed to elucidate factors of importance on the fuel combustibility as well as main ash matter implications during conversion on the grate.
Maryori C. Díaz-Ramírez

Chapter 5. Ash Fractionation Behavior During Fixed-Bed Combustion

Abstract
The experiences carried out with the 250 kW\(_{th}\) fixed-grate combustion unit provided a general knowledge about the combustion performance of brassica and poplar. They have highlighted the implications that the peculiarities of the fuels and, particularly, the ash attributes and fractionation behavior during combustion had on the overall combustion process efficiency.
Maryori C. Díaz-Ramírez

Chapter 6. Transformation Routes of K, Cl, S and P

Abstract
In the two previous chapters, the combustion conditions and fuel properties has been identified as influencing factors for the energy crop grate conversion.
Maryori C. Díaz-Ramírez

Chapter 7. Overall Assessment

Abstract
In previous chapters, the experimental background of this thesis has been presented. Results from the experimental research have shown important distinctions among the species tested at grate conditions. Special relevance was recognized for the ash matter fractionation behavior, the ash-related implications and the severity level of these ash-effects. The aforementioned aspects exhibited an influence on the interrelationship between the biofuel attributes and the applied fuel conversion conditions and were shown to be the determining factors on the overall combustion performance of grate-fired systems.
Maryori C. Díaz-Ramírez

Chapter 8. Conclusions, Research Contributions and Prospects for Future Work

Abstract
This chapter highlights the more relevant conclusions and research contributions derived from this research. In addition, prospects for future work are also included.
Maryori C. Díaz-Ramírez

Backmatter

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