Different kind of catalyst used in biomass gasification using different kind of reactors has been published in the literature. Corella et al. (2008a, b) used small pine wood chips as biomass in fluidized bed gasifier along with steam reformer reactor and two shift reactors for hydrogen production. They have reported 73 vol.% of hydrogen with 140 g/kg of biomass yield using Ni-based commercial catalyst. Furthermore, they stated that 90 % CO conversion to H2 via water gas shift reaction due to using of catalyst in the shift reactors. Along with the high production rate they have stated that not only the system is very complex with fluidized bed, steam reformer, and two shift reactors but also the hydrogen production cost is very high. Along with this they stated that the overall process is technically feasible, meaning that there are no technical major problems.

Li et al. (2009) studied the palm oil waste (mixture of EFB + fiber + shell) for hydrogen production. They used fixed bed reactor with pure steam as gasification agent and tri-metallic catalyst, i. e., NiLaFe/y-Al2O3. They have investigated the effect of steam/biomass ratio, temperature, and particle size on the hydrogen pro­duction. They reported 59 vol.% hydrogen with yield of 133.25 g/kg of biomass at 1,173 K and steam/biomass ratio of 1.33. Their results showed that hydrogen is increased by increasing temperature. For steam/biomass ratio, initially hydrogen increased by increasing steam/biomass ratio, but at high steam/biomass ratio hydro­gen decreased. This is due to the decrease of temperature at high steam/biomass ratio in fixed bed reactor. Furthermore, the smaller biomass particles produced more hydrogen compared to the bigger particle size. They have reported that the catalyst has a strong impact on the hydrogen yield in steam gasification of biomass. Hydrogen yield without catalyst was reported 39.75 g/kg of biomass and by using catalyst hydrogen yield increased till 101.78 g/kg of biomass under the same condi­tions. Furthermore, the type of catalyst also plays important role for hydrogen pro­duction in biomass steam gasification.

He et al. (2009) studied the catalytic steam gasification of municipal solid waste in bench scale fixed bed gasifier using calcined dolomite as catalyst. They reported that the catalyst not only increased the hydrogen yield but also completed decom­posed tar in the system in the presence of steam at high temperature. The highest hydrogen concentration was obtained 53.29 mol% with the yield of 84 g/kg of bio­mass. Furthermore, they reported that the system has potation to produce 140 g/kg of biomass hydrogen yield at high temperature. The use of catalyst has proved that there is remarkable increase in the hydrogen yield and concentration and decrease of CO and CH4 due to the water gas shift reaction and steam reforming of the hydro­carbons. They did not detect any tar during the catalytic steam gasification.

Xiao et al. (2010) utilized large amount of animal waste (livestock manure com­post) as biomass. They investigated the effect of temperature, steam, and catalyst using fluidized bed gasifier and Ni-Al2O3 as catalyst. They reported that the both temperature and steam are in favor of hydrogen concentration and yield in catalytic steam gasification, as the methane reforming and water gas shift reaction moves to the product side. Furthermore, catalyst simultaneously promotes tar cracking and steam reforming reactions.

Short bamboo fiber reinforced epoxy composites with varying fiber length, when tested for resistance to acetic acid, hydrochloric acid, toluene, carbon tetrachloride, benzene, ammonia, sodium carbonate, sodium hydroxide, and nitric acid show varia­tion in tensile load. This proves that bamboo fiber length affects the tensile load. The tensile load is found to be maximum at the fiber length of 30 mm (Rajulu et al. 1998).

2.4.5 Tensile Modulus

The tensile modulus of permanganate treated bamboo polyester fiber is seen to be increased by 118 % and that treated with benzoyl chloride is 118 % (Kushwaha and Kumar 2010). Bamboo fiber reinforced polypropylene composites show a signifi­cant increase in tensile modulus after addition of maleic anhydride polypropylene (MAPP) content in concentration of 24 % by weight. The composite is shown to have the tensile modulus of 5-6 GPa (Chen et al. 1998) . Due to high tensile modulus, bamboo fibers are excellent material for making composites (Rao and Rao 2007). By the addition of glass fiber by 20 % mass the tensile modulus of bamboo glass fiber reinforced polypropylene composite increases by 12.5 %. The reduction of tensile modulus in bamboo glass fiber reinforced poly propylene hybrid composites is two times more than reduction of tensile modulus in bamboo fiber reinforced poly propylene composites after 1,200 h of aging in water (Thwe and Liao 2002b). Tensile modulus of poly propylene based bamboo composites which use steam exploded fibers increases to about 30 %, due to well impregnation and reduction in void numbers (Okubo et al. 2004). The tensile modulus improves significantly with the addition of silane coupling agent Si69 in bamboo fibers (Ismail et al. 2002).

The chapter explored sugarcane world scenario, processing techniques, and also discussed the properties of bagasse fibers. Bagasse fibers extracted from sugarcane do not require very typical or complicated technical process. For the determination of physical properties like length of fibers Scion Image Software has also been dis­cussed in this chapter. The image method discussed in this chapter provides simple way for determination of bagasse fineness. The model used in this method can be used contrarily for evaluating the cross-sectional area when the fineness is known. The applications of bagasse fibers used in the various field were also discussed in this chapter. The other application of bagasse fiber is also found in composites making. It can be used as reinforcer in polymer matrix or concrete matrix compos­ites. These composites have good mechanical properties and can be used in house­hold, aircraft structures, and building structural applications.

Acknowledgement The authors are thankful and grateful to the Elsevier Ltd. for granting permissions to reproduce figures and tables to include in this chapter from their journals.

Cost evaluation for dry fiber production from A. comosus leaves is presented in Table 7.4. A slight increase of the production costs was found in the first crop plants compared with the plants from the second crop, which was due to the difference in productivity between both crops (Table 7.4). However, a similarity was found in the distribution of costs; fuel was the rubric which had most influence on the cost of the product, accounting for an average 70.1 % of the total cost, followed by manpower costs, with 29 % of total cost. Three workers were considered in the manpower rubric: one to operate the machine, the second to hand the leaves to the machine operator, and the third to collect and arrange plants for transportation or for drying.

Finally, the lowest cost was depreciation of the equipment with 0.9 % of the production costs. The cost of the equipment was of US$3,000 with a lifetime of 12

years which means that for plantations of 70,000 plants/ha, this rubric has little influence on the total cost. Costs of raw material or drying were not considered since the first comes from wastes and air-drying was used.

7.2 Conclusions

The quantity of leaves as well as the distribution by leaf length of A. comosus plants from the first and the second crops was different. The plants from the first crop produced less quantity of leaves per plant, therefore less quantity of leaves and less fiber per area unit (hectare). With respect to the scrapping machine prototype, pro­ductivity tests showed that the average processing capacity was 113 A. comosus plants/hour, slightly higher in the second crop than in the first crop, for the reason that the second crop plant had more leaves, thus allowing production of 4.9 kg/h of dried fiber. The fiber produced had an average 74 % moisture content and presented a greenish shade, which can be bleached with water, hydrogen peroxide 5 %, or chlorine 1 %, the most effective being chlorine 1 %, which gives the highest color change for pineapple fiber.

Lastly, a slight increase in production costs of the first crop plants was found compared with the second crop, due to the difference in the level of productivity of each type of crop. However, the distribution of costs was similar for both crops, since fuel accounted for 70.1 % of the total cost, followed by manpower with 29 %, and lastly by depreciation of the equipment with the lowest cost at 0.9 %. In addition, the average cost to produce 1 kg of dry fiber was US$0.49.

Fibres from Malvaceae family, in particular the most studied Kenaf fibre (Hibiscus cannabinus) from the Hibiscus family, have been investigated in detail and many reports can be found on the enhancement of composite properties through the incor­poration of this type of short natural fibre in non-biodegradable (Akil et al. 2011) and biodegradable matrices (Russo et al. 2013; Lee et al. 2012). The same approach was considered for the use of another similar fibre coming from the same family, okra (Abelmoschus Esculentus), and the recent study of thermal and mechanical behav­iour of this reinforcement confirmed that okra fibres can be efficiently used for the production of biodegradable composites (De Rosa et al. 2010a; Monteiro et al. 2012).

Up to now, okra fibres in materials have been mainly used in mucilage-based moisture absorbers (Gogus and Maskan 1999) or in its gum form as a source of poly­saccharides (BeMiller et al. 1993), which can be used after an appropriate chemical grafting (e. g. using poly-acrylonitrile) for the synthesis of biodegradable polymers or as a drug delivery system (Avachat et al. 2011) and viscosity modifiers for starches (Alamri et al. 2012). However, the possibility of using agro residuals in polymeric matrices implies, in the specific case of this herbaceous plant, a sound rethinking process, whose principal aim should be the possibility of using not only these fibres just as a waste material, but also ideally offering some reinforcement to a poly­meric matrix. Our previous studies on okra fibres demonstrated that well-known chemical treatments usually applied for natural fibres, such as bleaching or alkaliza­tion, do not significantly improve the fibre properties (Moniruzzaman et al. 2009; De Rosa et al. 2011), so the use of okra reinforced composites in structural applications seems to be difficult to be considered. On a lower profile, which can be recom­mended for materials aimed at large volume applications, where the compostability is a fundamental requirement, the use of easily available biomass, such as herbaceous plants, hardly appropriate for the production of textiles, coupled with the biodegrad­able polymer can be successfully exploited. In this case, the use of short fibres is also recommendable, in particular because the large presence of defects and the uneven fibre diameter result in a rather ineffective stress transfer and as a consequence in lower mechanical performance of the composite for fibres exceeding 5-10 mm length (Kirwan et al. 2007; Juntuek et al. 2012).

The use of okra fibres as reinforcement in thermoplastic biodegradable matrix also belongs to the latter domain. An example of application of okra fibres in ther­moplastic matrices comes from Fortunati et al. (2013c), in which poly(lactic) acid composites containing okra fibres were successfully produced and characterized. This study proved the potential of okra fibres in a context of applications for biode­gradable packaging and also suggested that an alkali treatment on okra fibre can have some positive effect on their use for the fabrication of composites with biopolymer matrix. Specifically, PLA/okra composites were prepared with several amounts of okra fibres (10, 20 and 30 wt%) by using both pristine (UOF) and alkali — treated fibres (ODC, okra derivative cellulose), considering a treatment procedure able to remove the amorphous fraction of the raw fibres. Specifically, okra fibres were firstly treated with 0.7 wt/vol% of sodium chlorite, after that a treatment with sodium bisulphate solution (5 wt/vol%) was carried out. Following this pretreat­ment, holocellulose (a-cellulose+hemicellulose) was obtained by gradual removal of lignin (Chattopadhyay and Sarkar 1946). The obtained holocellulose was treated with 17.5 wt/vol% NaOH solution, then filtered and washed several times with dis­tilled water. After that, the cellulose fibres were dried at 60 °C in a vacuum oven until constant weight. The introduction of these fibres in the polymer always resulted in a higher stiffness of the obtained composite system with an increase of about 30 % in Young’s modulus value with respect to the matrix. Moreover, the addition of okra fibre to the PLA matrix led to a significant nucleation effect, which improved in turn the ability of the polymer to crystallize: this effect was more evident in the composites containing ODC. A disintegration test in composting condition has been

also performed (Fig. 11.3), in order to have useful information about the post-use of the studied composite systems.

The introduction of 10 and 20 wt% of both untreated and treated fibres increased the disintegrability rate of PLA matrix; this behaviour can be explained considering that the hydroxyl groups of the cellulose structure act as catalysers for the hydroly­sis of the ester groups of the polymer. This result suggests the possibility to induce an acceleration of PLA weight loss due to the natural fibre introduction useful for the environmental impact of these composites during their post-use.

Optimized culture technologies are the key elements to regulate the effective cost of production of algal biomass for biogas production. There are various approaches for cultivation of algae, starting from solutions that are technically advanced in which the procedure is methodically checked and measured, to the low expected methods con­sisted of open tanks. Algal biomass is usually taken from the natural, degraded and eutrophic water bodies for the production of biogas (Zhong et al. 2012).

There are two processes by which algae is grown, (1) open culture system and (2) closed systems (also named as photobioreactors). In the course of the Second World War, Germans were the first, who comprehended the idea of growing algae in open ponds. Before that, algae were cultivated and used as food supplements. For CO2 reduction, mass harvesting of algae was initiated by a bunch of staff at Carnegie Institute in Washington when industrial development originated (Burlew 1953). Algae were commercially produced during early 1970s and late 1970s in Israel, Eastern Europe, and Japan. It was cultivated as nutritious diet in open ponds during 1970s period. Lake Chadand and Lake Texcoco in Africa were the main sources of production of Spirulina specifically for the families living in these zones. Cultivation of algae was also influenced by food and nutritious requirement of people living in these area. For water management in the United States, algal open pool system was established and the recovered enriched algal biomass was then transformed into methane, which was considered as the chief energy source (Burlew 1953). With the passage of time, in the aquaculture field, algal biomass production was considered as the most important (Muller-Feuga 2000). Algae have gained a lot of attention in recent years because of its capaci­ties in chemical production (Borowitzka 1999; Lorenz and Cysewski 2000) and also due to its use as the food supplement by both animals and humans (Dallaire et al. 2007). Some other applications of algae include the biosorption of heavy metals (Wilde and Benemann 1993; Lodeiro et al. 2005; Karthikeyan et al. 2007) and fixation of CO2 (Benemann 1997; Sung et al. 1999; Chae et al. 2006). There are certain advantages of closed system as compared to open pond system. The recommendations for photobioreactors have been made from laboratory to indus­trial scale. Because of the improved customized and controlled cultivation set­tings, closed photobioreactors have gained a lot of attention than open pond system. Adulteration can be avoided and greater algal biomass production can be attained in closed photobioreactor. A large number of photobioreactors have been examined for biomass production and cultivation of algae but only a limited num­ber of them are able to use solar energy. The main hindrance in the algal biomass production is the deficiency of effective photobioreactors. Transferal of photobio­reactor and detailed study of certain parts of hydrodynamics is essential for the improvement of algal biomass production. Characteristics of maximum number of open-air photobioreactors include uncovered illuminating areas. Flat and cylin­drical photobioreactors are considered favorable apart from facing the difficulty in surmounting the photobioreactor up. There are bioreactors that have better scaling ability but their usage in open-air cultures is restricted due to having less illuminating exterior. Such bioreactors include airlift, stirred tank, and bubble — column (Prajapati et al. 2013).

Homogeneous catalysts can be base catalysts, such as sodium hydroxide (NaOH) and potassium hydroxide (KOH) (Shimada et al. 2002), or acid catalysts, such as sulfuric, sulfonic, phosphoric, and hydrochloric acids (Georgogianni et al. 2009). Base catalysts possess higher catalytic efficiency, lower cost (Wen et al. 2010), and lower reaction temperature and pressure (Freedman et al. 1984) so they are preferred over acid catalysts. Heterogeneous catalysts also classified as acidic and basic. Such as sulfated metal oxide, heteropolyacids, acidic ion exchange resin, and sulfonated amorphous catalysts (Sakai et al. 2009) Ni-Ca-hydroxyapatite solid acid catalyst (Chakraborty and Das 2012) zinc oxide (ZnO), calcium oxide (CaO), stron­tium oxide (SrO) (Lam and Lee 2011), and Na/SiO2 (Akbar et al. 2009) and (Yusuf et al. 2012). Researchers used calcined washed Rohu fish scale (Labeo rohita) as a heterogeneous base catalyst with a maximum biodiesel yield of 97.73 % and up to six reuses (Chakraborty et al. 2011). Fly-ash-supported CaO catalyst from eggshell waste shows a performance of 96.5 % for biodiesel production (Chakraborty et al.

2010) . Some of the commonly used heterogeneous base catalysts are K/y-Al2O3 catalyst (Alonso et al. 2007), HTiO2 hydrotalcite catalyst (Barakos et al. 2008),

Ca and Zn mixed oxide (Ngamcharussrivichai et al. 2008), Al2O3 supported CaO and MgO catalysts (Umdu et al. 2009), alkaline earth metal oxides (Mootabadi et al. 2010), KF/Ca-Al, basic zeolites, alkali metal loaded alumina (Narasimharao et al. 2011). Basic heterogeneous catalysts have higher activity than acidic catalysts owing to shorter reaction times lower temperatures requirement in comparison to acidic catalyst.

The fruits of J. curcas are about 2.5 cm long and are ovoid in shape. Average fruit yields are about 3.5 tons ha-1, and, yields of 1-1.25 tons ha-1 are common when grown in wastelands under rain-fed conditions (Kumar et al. 2003). The fruit is made up of the shell and seeds. Two to three seeds are present in each fruit. It has nearly 400-425 fruits per kg and 1,500-1,600 seeds per kg weight (Singh et al.

2008) . In dry J. curcas fruit, shell accounts for 35-40 % and seed for 60-65 % of weight (Vyas and Singh 2007). All these components of the J. curcas fruit have been used as sources of bioenergy.

17.4.1 The Shell

The shell is removed mechanically during oil extraction from the fruit. One hectare of land under Jatropha plantation produces about one ton of shell material which can be used as energy source. The shell contains 34 % cellulose, 12 % lignin, and 10 % hemicelluloses. The shells have 16 % fixed carbon content, 15 % Ash, and 69 % volatile matter respectively (Singh et al. 2008). The J. curcas shell has caloric value of 16.9 MJ kg-1 (Vyas and Singh 2007) to 17.2 MJ kg-1 (Openshaw 2000) implying one hectare plantations can supply energy of 16.9-17.2 GJ vice shells alone. J. curcas shells owing to their chemical composition are also a good feed­stock for briquetting, bio-methanation and pyrolysis (Singh et al. 2008; Manurung et al. 2009; Sotolongo et al. 2009).

Biological pretreatments use microorganisms viz. fungi to solubilize the lignin. Biodelignification is the biological degradation of lignin by microorganism. Fungi have distinct degradation characteristics on lignocellulosic biomass. In general, brown and soft rots mainly attack cellulose while imparting minor modifications to lignin, and white-rot fungi more actively degrade the lignin component (Sun and Cheng 2002). Several white-rot fungi such as Phanerochaete chrysosporium, Ceriporia lacerata, Cyathus stercoreus, Ceriporiopsis subvermispora, Pycnoporus cinnabarinus, and Pleurotus ostreatus have been examined on different lignocellu — losic biomass showing high delignification efficiency (Kumar and Wyman 2009; Shi et al. 2008). Biological pretreatment by white-rot fungi has been combined with organosolv pretreatment in an ethanol production process by simultaneous sacchari­fication and fermentation (SSF) from beech wood chips (Itoh et al. 2003).

The biological pretreatment appears to be a promising technique and has very evident advantages, including no chemical requirement, low energy input, mild envi­ronmental conditions, and environmentally friendly working manner (Kurakake et al. 2007; Salvachua et al. 2011). However, its disadvantages are as apparent as its advantages since biological pretreatment is very slow and requires careful control of growth conditions and large amount of space to perform treatment. However, the main drawback to develop biological methods is the low hydrolysis rate obtained in most biological materials compared to other technologies (Sun and Cheng 2002).

It is known that the chemical composition of the natural fibers is of paramount in determining their suitability for different industrial applications particularly for NFRPC. That is, several characteristics of these composites like degradability and

Disorderly arranged

crystalline cellulose

microfibrils

Fig. 1.6 Structure of bio-fiber. Adapted from Azwa et al. (2013) recyclability, weather resistance, fungi attack, etc., strongly depend on the chemical composition of filler (fiber) (Al-Oqla and Sapuan 2014; Azwa et al. 2013). Actually, a variation in the fiber quality can be achieved for the same fiber type due to several factors. Some of these factors are: soil quality, fiber location on the plant, weather conditions, crop variety, fertilization, climate, and harvest timing (Dittenber and GangaRao 2011; Kalia et al. 2011b). In addition, extraction processing methods, fibers cross-sectional area variation, and the differences in drying processes will also affect the quality of the natural fibers (Dittenber and GangaRao 2011). Consequently, differences of natural fiber chemical and physical properties can be found in literature. Plant fibers consist mainly of cellulose fibrils embedded in lignin matrix. The bio-fiber structure is shown in Fig. 1.6 ; A primary cell wall and other

three secondary walls form the fiber’s complex layered structure whereas secondary thick middle layer of the cell walls consists of a series of helically wound cellular micro-fibrils formed from long chain cellulose molecules can determine the mechanical properties of fiber. Each cell wall is formed from three main compo­nents which are cellulose, hemicelluloses, and lignin. The lignin-hemicelluloses have a matrix-like role while the micro-fibrils which are made up of cellulose mol­ecules act as fibers (Dittenber and GangaRao 2011; John and Thomas 2008). Pectin, oil, and waxes can be found as other components (John and Thomas 2008; Wong et al. 2010). Due to the existence of Lumen, the natural fiber has a hollow structure unlike synthetic ones (Liu et al. 2012).

Cellulose and lignin are the most important structural components in many natu­ral fibers. In plants, cellulose is usually found as a slender rod like crystalline micro-fibrils and aligned along the fiber’s length (Azwa et al. 2013). Although Cellulose is resistant to hydrolysis, strong alkali, and oxidizing agents, it is degrad­able to some extent when exposed to chemical treatments (Azwa et al. 2013). Lignin is a complex hydrocarbon polymer. It usually gives rigidity to plant and assists in water transportation. It is hydrophobic, resists most of microorganisms attacks as well as acid hydrolysis, it is usually soluble in hot alkali, readily oxi­dized, and easily condensable with phenol. The nature of cellulose and its crystal­linity can determine the reinforcing efficiency of natural fibers (John and Anandjiwala 2007). Filaments are bonded into a bundle by lignin and are attached to stem by pectin. Lignin and pectin are weaker polymers than cellulose. They have to be removed by retting and scotching for effective composite reinforcements (Dittenber and GangaRao 2011). The average weight percentage of chemical com­position of the date palm tree frond and their fiber properties (Mirmehdi et al. 2014; Sbiai et al. 2010) are shown in Table 1.2.

It can be noticed that there are some variation in the measured values of the date palm fiber’s chemical composition due to inherent parameters mentioned previ­ously. A comparison between average values of both cellulose and lignin for the date palm fiber with other natural fibers can demonstrate the appropriateness and competitiveness of the date palm fibers for being potential type of fillers for natural fiber composites. Such comparison is demonstrated in Fig. 1.7.

It can be seen from the comparison that the date palm fiber has an added value over both hemp and sisal, because it has less cellulose content than they do which reduces the ability of the date palm fiber to absorb water comparing with hemp and sisal (Al-Oqla and Sapuan 2014). On the other hand, this can give the date palm fiber more desired mechanical properties over the coir one. Moreover, the cellulose content in date palm fiber is greater than that of lignin, which allows it to be competitive for automotive applications (Al-Oqla and Sapuan 2014).