Sustainability, Business Models, and Techno-Economic Analysis of Biomass Pyrolysis Technologies

The objective of this chapter is to review and discuss sustainability and techno-economic criteria to integrate pyrolysis, biochar activation, and bio-oil refining into sustainable business models. Several business models such as the production of biochar with heat recovery and bio-oil refining are discussed. Cost data needed by engineering practitioners to conduct enterprise-level financial analyses of different biomass pyrolysis economy models are presented. This chapter also reviews life cycle assessments of pyrolysis business models. If the feedstock used is produced sustainably and if the pyrolysis vapors are used for bio-oil or heat production, both, the production of biochar through slow pyrolysis and its use as a soil amendment to sequester carbon, and the production and refining of fast pyrolysis oils to produce transportation fuels could have a positive environmental impact.

Energy and Exergy Analysis on Gasification Processes

In recent years, attention has focused on exergy analysis, a type of thermodynamic analysis which is an important tool for the efficiency assessment and the processes optimization when dealing with energy conversion and, particularly, thermochemical processes such as gasification. Thus, this chapter aims to introduce the fundamental concepts of energy and exergy and describe the energy and exergy evaluation tools, elucidating its importance for calculations applied to gasification processes. A case study was performed to show the proposal of energy and exergy analysis. Therefore, a single global gasification chemical reaction was used to represent the gasification process. This analysis can provide a tool to assess and develop models, simulations, calculations, and to optimize real gasification processes. Information and experiences covered in this chapter help to be put into perspective the technology, research and overcoming of challenges.

Fluid Dynamic and Mixing Characteristics of Biomass Particles in Fluidized Beds

The study of fluid dynamic and mixing characteristics of biomass particles in fluidized beds is fundamental for comprehension of thermal conversion processes. In this chapter a review of literature showed a large lacks of technical information about the quality of fluidization and representative models concerning binary mixtures (biomass and inert). A case study was presented involving Eucalyptus grandis wood and tucumã endocarp in order to obtain fluid dynamic parameters such as the characteristic fluidization, velocity and porosity, and the bed expansion. These parameters were more significant for mixtures with smaller diameter and mass fraction ratios, and sphericity ratio, due to the facility of beds to fluidize. A map was presented to identify the limits of effective mixtures considering four classes as a function of the complete fluidization Reynolds' and Archimedes' numbers. Empirical correlations have been proposed and showed a good agreement with the experimental work.

Effect of Steam Explosion Pretreatment on Size Reduction and Pellet Quality of Woody and Agricultural Biomass

Steam explosion is a thermo-chemical pretreatment widely used to disrupt the ultra-structure of the cell wall of the ligno-cellulosic fiber to improve the fractionation of the major ligno-cellulosic components of the biomass for biochemical conversion. In recent years, steam explosion pretreatment has been applied on the fibers for improving the pellet quality of woody and agricultural biomass for thermo-chemical conversion. The improved qualities include high bulk density, low equilibrium moisture content, higher heating value, mechanical strength and moisture resistance. All of these desirable properties allow the steam exploded pellets to be handled and stored outdoors safely, similar to coal. This also raises lots of interests in considering pellets as preferable feedstock for the thermal power plant or bio-refinery facilities. In this chapter, the state of art of research findings on the effect of steam explosion on size reduction and pellet quality of woody and agriculture biomass will be discussed.

Microwave Heating Assisted Biorefinery of Biomass

This chapter debates the potential of the biorefinery of biomass using microwave heating. First, the essential information regarding electromagnetic radiation is explained and the pros and cons of microwave heating versus conventional heating, especially in the thermochemical treatment of biomass, are discussed. Different methodologies for predicting and measuring the temperature gradient within a material subjected to electromagnetic waves are demonstrated. The chapter summarizes the key conclusions of various investigations regarding the effects of microwave heating on chemical reactions and presents how electromagnetic radiation can assist the biorefinery of biomass. Finally, the issues and limitations regarding scaling-up microwave heating are elucidated, along with possible solutions to these problems.

Liquid Products Characterization from Pyrolysis and Gasification

In this chapter there is described a tentative of obtain and characterize pyrolysis liquids from cashew nut shell, using a suggested classification of tars. The large amount of tar definitions and measurement methods, as well as the wide spectrum of organic compounds, makes it almost impossible to capture “tars” with a clear definition. And so, in order to facilitate the study of the evolution of liquid fraction composition, the compounds have been grouped according to their chemical nature, but differently from other works, it was extended the range of compounds in order to evaluate the influence of the reactor parameters in liquid fraction compositions. It is described, as well, the pyrolysis and gasification of cashew nut shell, that has been studied in a laboratory scale reactor. It was quantified and classified the production of liquids (tar) and evaluated the final temperature influence (800, 900 and 1000 °C) and the use of N2 in pyrolysis case, and a mixture of N2 and steam or air in the gasification case. Finally, it is described the identification and quantification of tar compositions, by CG-MS and CG-FID analyzes. Around 50 different compounds have been detected in the liquid fraction obtained, most of them being present at very low concentrations and it is observed that in the pyrolysis and gasification processes, phenol and benzene were the major chemical groups, and this fact agree with others works, presented here in a bibliographic revision.

Modeling Size Reduction and Fractionation for Cellulosic Feedstock

Biomass has attracted attention as a source of renewable energy. It is available in different forms such as lignocellulosic stalks of herbaceous and woody biomass. These forms of biomass should be prepared to go through bioconversion process or biofuel production. One of the major unit operations for preparation is size reduction, which increases the surface area available and breaks the structure of biomass. Size reduction is energy intensive and an expensive step of feedstock preparation. The characteristics of ground particles are the result of interactions between material properties and the modes of size reduction like shear, impact, and attrition. The fundamentals of size reduction of fibrous biomass are not well understood. This chapter summarizes the latest studies on modeling of size reduction of lignocellulosic and woody biomass.

Modeling the Kinetics of Lignocellulosic Biomass Pyrolysis

The study of the kinetics involved in lignocellulosic biomass pyrolysis has received great attention in the last decades and different mathematical models have been derived. In this chapter, a literature review was performed in order to summarize the existing models that use thermogravimetric data to estimate the kinetic parameters, which are important to improve and optimize the process. Additionally, a case study was presented exemplifying the application of kinetic modeling for the residue of one Brazilian species (Brazil nut woody shell). The isoconversional models of Ozawa-Flynn-Wall, modified Coats-Redfern, and Friedman were applied, as well as three and four independent parallel reactions models. The four reactions model presented the best fit between experimental and theoretical data, providing a better representation of the biomass pyrolysis reaction.

Technical and Marketing Criteria for the Development of Fast Pyrolysis Technologies

The management of projects regarding the use of biomass requires human resources with specific technical knowledge and tools to assess the real potential of raw materials within one or several production chains. Storage and transportation logistics, conservation and handling of the biomass, available technologies of transformation, and consumer market for the products are critical stages in the management process. The following chapter will present the technical, financial, and market criteria for managing production chains that use biomass as raw material in processes of fast pyrolysis.

Biomass Processing Routes for Production of Raw Materials with High Added Value

In this chapter sugarcane bagasse may be submitted to a biological route in which the technologies used to obtain lignocellulosic ethanol (2nd generation ethanol) from lignocellulosic materials involve pre-treatment and the hydrolysis of the polysaccharides in the biomass into fermentable sugars for subsequent fermentation. Taking into consideration the use of sugarcane bagasse as a raw material for 2nd generation ethanol, the acid hydrolysis / pretreatment of sugarcane bagasse could be more feasible that others, and must be evaluated in this context. On the other hand, from biomass is possible to obtain products with high added value and energy, mainly by the use of thermochemical processes (e.g. pyrolysis and gasification) and biochemical processes (e.g., fermentation and anaerobic digestion). However, the products obtained from the thermochemical processes can be used as raw material for biochemical processes which multiplies the quantity of products to be obtained from biomass.