**6. Conclusions**

*Biotechnological Applications of Biomass*

renewable fuel for baseload power can be achieved.

ment costs, transportation costs, pre-treatment, etc. [4].

**3. Economics of biomass torrefaction**

for production with CAPEX.

**4. Sustainability of biomass torrefaction**

challenges. It can cause deforestation and it is not entirely clean.

Sustainability concept of biomass torrefaction can be properly broadly categorized into three factors; (1) economic factor, (2) environmental factor, and (3) social factor [4]. Generally speaking, the economic factor is majorly related to the fossil fuels dependence and renewable energy consumption whereas the

power plants.

energy, hydrophobicity, increased energy density, and lower moisture content. As a source of a power source, with torrefied biomass, low net carbon energy source and

While ensuring the conversion of biomass into renewable energy for the benefits of mankind, it is necessary to consider the economics aspect of biomass torrefaction. That is, the costs of generating high-grade fuel should be affordable. The economic features of the torrefaction process covers the total production cost, total capital investment, production capacity, feedstock input, feedstock type, procure-

For effective economy analysis, economic optimization of the system, including the extended fuel supply to application system, and integrated process between torrefaction and gasification as well as torrefaction and gasification should be properly looked into. The cost of the torrefaction process which is higher than that of coal at times can be greatly reduced by improving the empirical cumulation and torrefaction plant equipment size and as well as the utilization of carbon credits market. The total costs during the torrefaction process is often influenced by the important sensitivity parameters including the torrefaction plant CAPEX and torrefaction mass yield, drying technology, biomass moisture content, logistics equipment, biomass premium, and the quantity of the available biomass [2, 3]. Meanwhile, the depreciation, biomass delivery costs, energy consumption, labor, capital expenditure, biomass delivered costs are the common influencing factors

Biomass torrefaction is widely regarded as a breakthrough technology accounting for the world largest renewable energy which reduces the investment for co-firing application as well as decreasing the storage and handling costs thereby making the process economically viable and serving as a potential way of replacing coal in

Biomass torrefaction involves the conversion of biomass into a coal-like material with improved fuel properties as compared with the original biomass. It is presently a vital tool for the sustainable development in many developed and developing countries with the aim of supporting large scale utilization of bioenergy through the reduction of carbon dioxide (CO2) at source and other emissions which may be harmful to the community. That is, the production of solid sustainable energy can be obtained through biomass torrefaction. It is important to note that biomass torrefaction can pose threats to humanity since some harmful toxins and greenhouse gases are usually generated and released into the atmosphere during biomass combustion resulting into environmental problem. Carbon dioxide (CO2) remain the greenhouse gas with the largest volume and percentage released into the atmosphere when compared to other greenhouse gases. Biomass as a renewable energy which has some similar features with fossil fuels still have some environmental

**600**

Biomass upgrading for the production of high-grade solid fuels with greater energy density, excellent grindability, and enhanced durability can be achieved by subjecting the original raw biomass to thermal mild pretreatment process under inert atmosphere without the presence of air or oxygen. This process is commonly referred to as torrefaction. The major aim is to improve the chemical, thermal, and physical properties of biomass for a long-term storage through the elimination of oxygen, reduction of moisture content and change of chemical compositions. After torrefaction, some challenges pertaining to technological applications of biomass such as difficulty to obtain a small particle size and high oxygen–carbon ratio, can be properly addressed.

Upon the mild thermal pyrolysis of raw biomass in oxygen-free or N2 atmosphere at moderate temperatures over a period of time, the biomass fiber structure tends to break down which makes the biomass easy to grind, hence an enhanced energy density. By this process, the properties of raw biomass including low calorific value, grindability, hydrogen-carbon and, hygroscopicity, can be greatly improved. At first, torrefaction process can reduce the weight of the biomass to about 30%, but the final solid biofuel produced can retain about 90% of the original biomass energy content.

As compared to the original raw biomass, torrefied biomass can serve as a good replacement for coal in the generation of heat and electricity, as well as input for gasification, densification, and iron making processes, with many positive attributes, like grinding and burning like coal, lower ash and sulfur content, lower transport and shipping costs, lower feedstock costs, and the ability to produce non-intermittent renewable energy. Hence, further studies to understand the mechanism behind the torrefaction process in producing more uniform biomass products and the influence of torrefaction process parameters on the biomass feedstock upgrading is necessary to open the market for the mass production of high-grade solid biofuels with enhanced energy density and hydrophobicity for a long-term storage.

Attributed to the several reactions involved, biomass torrefaction is sometimes referred to as the complex reactions including the decomposition of the common biomass components including lignin, cellulose, and hemicellulose as well as moisture evaporation. The economic, environmental, and social factors are the three major concepts of sustainability as regards the biomass torrefaction. While the economic factor is majorly related to the renewable energy consumption, the environmental factor focused more on the sustainable forest management while the regeneration of rural areas and more jobs is related to social factor. The economics of biomass torrefaction including the total production cost, total capital investment, production capacity, feedstock input, feedstock type, pre-treatment, and procurement costs, transportation costs are necessary to evaluate the efficiency of the torrefaction process as well as the reactor performance.

**603**

**Author details**

Temitope Olumide Olugbade

Technology, P.M.B. 704, Akure, Ondo State, Nigeria

provided the original work is properly cited.

\*Address all correspondence to: tkolugbade@futa.edu.ng

Department of Industrial and Production Engineering, Federal University of

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Economics, Sustainability, and Reaction Kinetics of Biomass Torrefaction*

*DOI: http://dx.doi.org/10.5772/intechopen.94400*
