**4. Potential biomass feedstocks**

Biomass being considered for bio-oil production includes woody biomass, grass and most recently different types of micro- and macroalgae. The characteristics of these feedstocks will be introduced here giving more emphasis on oil palm biomass which is selected as one of the main materials investigated in this work.

### **4.1. Oil palm biomass**

Malaysia is one of many agricultural countries in the world, producing main agricultural crops such as oil palm, rubber, cocoa, rice and coconut [16]. Hence, the amount of production of agricultural wastes and residues is staggering with 47762 ktons of biomass generated as of year 2007. These biomass feedstocks have been long identified as a source of renewable energy which could reduce the dependency of fossil fuels as the main source of energy supply and multiple fine chemicals. The abundance of various biomass feedstocks has provided a good potential for their utilization. Thus, this has been extensively investigated more especially in looking for the best technology applicable for this conversion into either fuels or fine chemicals more efficiently, effectively and economically. Among the many available biomass feedstocks, those that are abundantly present in the Southeast Asian region are mostly derived from oil palm plantation.

Oil palm plantation in Malaysia is the most important agricultural crop, producing biomass close to about 37.0 million tons in 2008. This biomass consists of 22% empty fruit bunch (EFB), 13.5% fruit press fiber (FPF) and 5.5% shell. This high amount of oil palm biomass wastes could be utilized in the production of bio-oil, a promising future renewable energy source. In this research, the oil palm wastes such as empty fruit bunch (EFB), mesocarp fiber (MCF) and palm kernel shell (PKS) will be utilized as feedstocks for the hydrothermal liquefaction process to produce bio-oil using sub- and supercritical water technologies as depicted in Fig. 1. Fig. 3 shows images of the samples and the lignocellulosic composition with respect to the lignin, hemicellulose and cellulose contents. The EFB has lower lignin content at about 18%. The PMF and PKS have almost similar composition consisting of about 30–33% lignin, 22% hemicellu‐ lose and 24% cellulose. These changes in composition could have significant effect on its liquefaction. Table 1 summarizes the ultimate analysis and high heating value (HHV) of the samples. The EFB has the lowest carbon content at 43.6%, but has the highest oxygen content at 50.2%. The HHV of EFB and PMF are almost the same at 16.3 MJ/kg, while PKS has about 17.5 MJ/kg of heat value.

8 Book Title

2 Empty fruit brunch (EFB) Palm mesocarp fiber (PMF) Palm kernel shell (PKS)

1

3

challenging and hot topic, a device for direct observation of channel-tee mixing has been developed for this purpose [14]. Further, a reactor for the studies of in-situ X-ray scattering studies of nanoparticle formation in supercritical water system was also developed [15]. The advantages of supercritical fluids with regard to its physicochemical properties are summar‐ ized in Fig. 2, including easily tunable physical properties which make the water suitable for

Biomass being considered for bio-oil production includes woody biomass, grass and most recently different types of micro- and macroalgae. The characteristics of these feedstocks will be introduced here giving more emphasis on oil palm biomass which is selected as one of the

Malaysia is one of many agricultural countries in the world, producing main agricultural crops such as oil palm, rubber, cocoa, rice and coconut [16]. Hence, the amount of production of agricultural wastes and residues is staggering with 47762 ktons of biomass generated as of year 2007. These biomass feedstocks have been long identified as a source of renewable energy which could reduce the dependency of fossil fuels as the main source of energy supply and multiple fine chemicals. The abundance of various biomass feedstocks has provided a good potential for their utilization. Thus, this has been extensively investigated more especially in looking for the best technology applicable for this conversion into either fuels or fine chemicals more efficiently, effectively and economically. Among the many available biomass feedstocks, those that are abundantly present in the Southeast Asian region are mostly derived from oil

Oil palm plantation in Malaysia is the most important agricultural crop, producing biomass close to about 37.0 million tons in 2008. This biomass consists of 22% empty fruit bunch (EFB), 13.5% fruit press fiber (FPF) and 5.5% shell. This high amount of oil palm biomass wastes could be utilized in the production of bio-oil, a promising future renewable energy source. In this research, the oil palm wastes such as empty fruit bunch (EFB), mesocarp fiber (MCF) and palm kernel shell (PKS) will be utilized as feedstocks for the hydrothermal liquefaction process to produce bio-oil using sub- and supercritical water technologies as depicted in Fig. 1. Fig. 3 shows images of the samples and the lignocellulosic composition with respect to the lignin, hemicellulose and cellulose contents. The EFB has lower lignin content at about 18%. The PMF and PKS have almost similar composition consisting of about 30–33% lignin, 22% hemicellu‐ lose and 24% cellulose. These changes in composition could have significant effect on its liquefaction. Table 1 summarizes the ultimate analysis and high heating value (HHV) of the samples. The EFB has the lowest carbon content at 43.6%, but has the highest oxygen content at 50.2%. The HHV of EFB and PMF are almost the same at 16.3 MJ/kg, while PKS has about

highly selective extraction and reaction processes involving biomass samples.

**4. Potential biomass feedstocks**

main materials investigated in this work.

**4.1. Oil palm biomass**

462 Biofuels - Status and Perspective

palm plantation.

17.5 MJ/kg of heat value.

**Figure 3.** Lignocellulosic composition of Malaysian oil palm biomass samples.


4 **Fig. 3.** Lignocellulosic composition of Malaysian oil palm biomass samples.

10 Nitrogen (N) (%) 2.0 1.4 0.5

**Table 1.** Ultimate analysis and HHV of various Malaysian oil palm biomass samples

### **4.2. Algal biomass (microalgae or macroalgae)**

Algae are considered to be primitive plants lacking in roots, stems and leaves [17]. This inherent structure of these type of plants makes it very suitable for energy production [18]. Thus, its use as feedstocks for bio-oil production is gaining popularity in recent years due also to the presence of some functional components including oils, proteins and carbohydrates [8]. Among the various types of algae, microalgae are the most potential energy source because cultivation and production of these biofeedstocks do not match those for food production [5]. The concept of bio-oil conversion using these materials has been introduced in 1970s, but mainly focused on direct thermochemical method. Recently, liquefaction under hydrothermal condition has also received increasing attention because of the advantages the method can offer for rapid reaction, no pre-drying of samples and no restrictions due to lipid contents [8]. Hydrothermal liquefaction (HTL) converts biomass feedstocks into four phases including the biocrude oil (or simply referred to as bio-oil), aqueous products, solid residue and gaseous products.
