Page 35 - Refining Biomass Residues for Sustainable Energy and Bioproducts

14 Refining Biomass Residues for Sustainable Energy and Bioproducts

immiscibility with other fuels.
Apart from using pyrolysis, there are others methods can be used for the produc-
tion of bio-oil from the sewage sludge, such as liquefaction or hydrothermal lique-
faction (Lin et al., 2018).

1.7 Overview of the conversion of biomass to fuel

Biomass can be used directly as biofuel or can be converted into gaseous fuel or
liquid. Mostly there are two ways in which energy obtained from the biomass either
by burning the biomass and get some energy otherwise that can be allowed for sev-
eral biological conversion methods for the production of high quality fuel.
Conversion technologies can be classified into three different types based on the
products obtained from the biomass.

1. Thermochemical conversion
2. Biochemical conversion
3. Oil extraction
For generation and utilization of biomass, three main approaches are adopted:
gathering of urban and industrial wastes as beneficial fuel in boilers and as a feed-
stock for methane and fuel production; agriculture and forest residues collected for
fuel production, organic manures, and chemical feedstock; growth of some particu-
lar energy plants for use as energy feedstock and development of commercial
ranger service, aquatic and marine plants for various products. Liquid biofuels are
categorized into three different types such as
1. alcohol,
2. plant seed oil, and
3. biocrude and synthetic oil.
Biofuels are produced through several conversion processes of biomass, such as
pyrolysis, gasification, combustion, and fermentation. In these methods, biomass
can be converted into different valuable products such as charcoal, fuel, and gas by
reacting with factors such as heat and environmental oxygen. Fuel from biomass
can have the three main objectives:
Production of clean burn fuel with less smoky and without generation of any by-products
like tar
Production of high calorific value fuel than that of initial feed materials
Production of more reactive fuel
In gasification the fuels and other products can be produced by using gasifier. It
occurs in three stages, oxidation and other exothermic reaction, pyrolysis, and gasi-
fication or reduction. Two types of gasifiers are most commonly used for the con-
version process, such as fixed-bed gasifier and fluidized-bed gasifiers (Mittal,
1996). The production of fuel from biomass was shown in Fig. 1.4.