Application of Analytical Chemistry in the Production of Liquid Biofuels

Silvio Vaz Jr. and Jennifer R. Dodson

Abstract Analytical techniques are vital for the development of new added-value materials and products from biomass, such as liquid biofuels, by evaluating the quality and chemical composition of the raw materials and all materials and byprod­ucts in the production process. This also enables the evaluation and implementation of environmental laws and better understanding of the economics of new biomass processes. Different analytical techniques are applied to different biomass feed­stocks, such as sugarcane, soybean, corn, forests, pulp and paper, waste and agri­cultural residues, dependent on the final end biofuel product. This chapter highlights how the use of analytical chemistry can be used as a tool to ensure quality and sus­tainability of the biomass and liquid biofuels, with, some aspects of green analysis also considered.

1 Introduction

The technological development of modern society is increasingly resulting in the need for methods to control products and processes, to ensure that they fulfill quality standards, and to prevent negative impacts on the environment. The increasing demand from society for more sustainable and lower impact products has become important across all aspects of production, including in agricultural sector. The agri­cultural sector has proposed in recent years to reduce the generation of greenhouse

S. Vaz Jr. (*)

Brazilian Agricultural Research Corporation (EMBRAPA), Brasilia, DF, Brazil e-mail: silvio. vaz@embrapa. br

J. R. Dodson

Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil

A. Domingos Padula et al. (eds.), Liquid Biofuels: Emergence, Development and Prospects, Lecture Notes in Energy 27, DOI: 10.1007/978-1-4471-6482-1_9, © Springer-Verlag London 2014

gases through increased yields combined with the application of sustainable practices, e. g., lower tillage per area, a decrease in the use of agrochemicals, and a decrease in the water usage. One example of how agriculture could contribute to reductions in greenhouse gases worldwide is through the use of biomass for bio­energy applications, particularly the production of liquid fuels such as bioethanol and biodiesel from agricultural crops and waste products to replace petroleum feedstocks (Grafton et al. 2012; Norse 2012; Rathmann et al. 2010; Balat and Balat 2009; Goldemberg et al. 2008).

There are four main types of biomass which can be used to produce liquid bio­fuels: oleaginous, sugary, starchy, and cellulosic (International Energy Agency 2013). For instance, soybean (Glycine max) and oil palm (Elaeis guineensis) gen­erate oils for biodiesel production; sugar from sugarcane (Saccharum spp.) and sorghum (Sorghum bicolor (L.) Moench) and starch from corn (Zea mays) can be used to produce first-generation ethanol (1G ethanol); while bagasse, straw, and cellulosic wood are applicable for second-generation ethanol (2G ethanol). Each one has unique structural and chemical characteristics, which therefore require different analytical technologies and approaches to better understand the process­ing of the materials, the products formed and economic aspects. Analytical meth­ods are vital for enabling quality control of raw materials and products, providing accurate knowledge for the regularization of products and markets (Scarlat and Dallemond 2011; Orts et al. 2008). Analytical techniques can therefore support the development of new products and processes from biomass, helping to promote a bioeconomy (Gallezot 2012). Chemical analyses, either based on classical or instrumental techniques, play an important role in the exploitation of biomass as supporting technologies for all stages of biomass processing and for different bio­mass sources, including sugarcane, soybean, corn, forests, pulp and paper, waste and agricultural residues, among others (Feng and Buchman 2012; Sluiter et al. 2010; Orts et al. 2008).

Fundamentally, a liquid biofuel is defined as:

• Liquid state under normal conditions of temperature and pressure (25 °C and 1 atm, respectively);

• Lower vapor pressure and high energy content;

• Presence of oxygen in almost all biofuels;

• Obtained from a chemical synthesis process: biodiesel by transesterifica­tion (Meher et al. 2006); biokerosene by transesterification and esterification, followed by distillation (Llamas et al. 2012); and gasoline and diesel by Fischer-Tropsh (Balat and Balat 2009);

• Obtained from a fermentation process: ethanol by Saccharomyces cerevisiae strain (Balat and Balat 2009), and n-butanol by Clostridium acetobutylicum strain (Lu et at. 2012).

The practical application of analytical techniques for chemical analysis of feed­stocks and biofuels is discussed in this chapter in order to convey their potential use for technical or scientific applications. Alongside, some aspects of green anal­ysis, quality control, and technological trends are considered.

Fig. 1 Some chemical structures of fatty acids from oleaginous plants such as soybean. Author Silvio Vaz Jr

Table 1 Chemical composition of oils extracted from oleaginous biomass (Gunstone 2004)

Plant

Palmitic acid

Stearic acid

Oleic acid

Linoleic acid

Triacylglycerols

(% m/m)

(% m/m)

(% m/m)

(% m/m)

(% m/m)

Palm oil

44

4

39

10

3

Soybean

11

4

23

8

1