Biocomposite industry is acknowledged as an important contributor to the eco­nomic growth of other industries. The biocomposite industry value chain begins from the preparation of agricultural biomass raw materials and resin production to produce consumer products (Fig. 5.11). Reduction in the supply of raw materials has caused concern and, in this context, agricultural biomass raw material is used as an alternative material for the industry to produce value-added biocomposite prod­ucts. Therefore, research and development sectors are encouraged to explore the potential of natural resources for the production of new value-added products to enhance growth, competitiveness and sustainability of biocomposite industry.

Biomass raw material

Wood waste/saw dust

Oil palm-based fibres

Bamboo

Kenaf

Coconut

Rice husk

Bagasse

Banana stem

Pineapple leaf

Fig. 5.11 Value chain of the biocomposite industry

9.3.1 Straw Quality and Availability

The first and foremost investigating issue is the residual amount on standing crops as well as the amount left on the ground after harvesting of green cane. A wide variation is observed in the documented data and the available information does not allow complete comparison due to lack of knowledge on a number of essential issues like methodology followed, varieties of sugarcane studied, moisture content of yield and straw, etc.

Hassuani et al. (2005) summarized the results of a seven-year project covering many aspects of availability of sugarcane straw, its quality, routes of recovery and related cost, agronomic impact, impact on the environment, and use for power gen­eration in advanced systems (biomass integrated gasification/gas turbine). Hassuani et al. reported three varieties of sugarcane in three (3) different ages, i. e., first har­vest, third harvest, and fifth harvest. The straw amount varied from 10 to 18 mg ha-1; dry basis and the ration of straw (db) to stalk (wet basis) lied in the range of 11-17 %. The literature showed that the yield of straw ranged from 7.4 to 24.3 mg ha-1 (db), whereas the straw to stalk ratio was between 9.7 and 29.5 %. The average was

14.1 mg ha-1 and 18.2 %, respectively (Hassuani et al. 2005). In potential assess­ments, it is normally accepted that the straw to stalk ratio lies between 14 and 18 %, which clearly reveals that the total amount of straw available is highly dependent on the sugarcane yield.

With regard to the characteristics of straw, the main focus is on two of the most promising uses of straw, i. e., fuel for generation of power and provision of feedstock for the biofuel of second generation. As far as fuel for power generation is concerned, it is mandatory to gather all the information about the proximate and ultimate analyses including the ultimate analysis of the mineral content as the comparison with bagasse is of extreme importance since bagasse can be burned in the same type of equipment, either separated or mixed. The studies further reveal that analyses for three main straw components were carried out: green leaves, dry leaves, and tops. This separation was generated because it had the tendency to display characteristics with marked differences and their role in the final composition of the recovered straw, which depends on the methods used for its collection and the procedures used in harvesting, for instance, whether or not the tops should be removed by the har­vester. Several field experiments were conducted in which the average participation was 31, 62, and 7 % for green leaves, dry leaves, and tops, respectively (dry basis) (Leal et al. 2013).

Similar results were presented by straw and bagasse except for the content of moisture, i. e., in terms of combustion chamber design; the bagasse-fired boiler could be used for straw burning. Other than that, the higher content of chlorine, especially in the tops, could cause corrosion in the boilers. The highlighting differ­ences between the components of bagasse and straw are as follows:

1. Increased content of potassium in straw (mainly in the tops) that can be the rea­son of the deposits found on hot surfaces, ash slags, and corrosion.

2. Levels of magnesium and calcium in the straw. Even though they are in higher concentration when compared with bagasse, still it is expected that they do not cause any problem in the boilers (Leal et al. 2013).

The microwave remote sensing technology can be used to acquire the qualitative and quantitative information related to earth’s surface from space or airborne plat­forms and is not influenced by the presence of clouds, light conditions and heat reaching towards it. The microwave systems are principally well suited for the assessment of woody biomass and other applications related to agriculture due to the fact that the signals of different wavelengths interact with particular part of the vegetation structure at different range of wavelengths. Thus interacting microwave radiation enables the rescue of vegetation structure parameters and related compo­nents of the standing woody biomass, rather than just the greenness of the top layer of a canopy which is depicted by the visible and infrared remote sensing technology (Koch et al. 2008; Woodhouse 2006a, b). The microwave radiation used for interac­tion with woody vegetation is categorized according to the applied parameters such as frequency, wavelength, reflection, refraction, diffraction, interference, polariza­tion and scattering. When compared to each other, these characteristics leads to the distortion of incident waves following the interaction in different forms of scattering such as reflection, diffraction and reflection by the elements present in biomass and this distortion is similar in size or less than for what can be observed during the change of wavelengths. However, the occurrence of reflection is due to the scatter­ing of waves from vegetation surfaces with specific features that are much smaller than the wavelength scale and similarly, the generation of diffraction signal are due to the scattering of incident waves at distinct boundaries. The radar remote sensing technology utilizes the backscattering signal, i. e. the intensity of signal which is reflected by the target and is received by the antenna. For point that is coherent tar­gets, the radar equation provides the estimation for magnitude of received power and is shown in Eq. 12.12 (Woodhouse 2006a).

Fig. 12.1 Schematic representation of Fresnel reflection onto a natural surface

where Pr and Pt corresponds to the received power and transmitted power, respectively; R is the distance between radar site and the location of target; G is the signal gain by the antenna; Ae is the effective area of the antenna; and a is the radar cross section of the object. The radar cross section (a) is the measure of radar reflec­tivity which indicates the strength of radar signal reflected from unit area of the target (Boyd and Danson 2005). When dealing with distributed targets especially the incoherent targets, a is replaced by sigma nought (a°)10 which is defined as the radar cross section per unit area (Woodhouse 2006a; Raney 1998).

An activated carbon is amorphous-based material and can be defined as “a material exhibiting a high degree of porosity and a prolonged inter-particulate surface area” (Bansal et al. 1988). A black solid substance resembling granular or powder charcoal regarded as activated carbon that possesses highly internal surface area, highly developed porosity, relatively high mechanical strength (Sahu et al. 2010). Activated carbon is the best example of heterogeneous acid catalyst. Adsorption and desorp­tion are the process through which catalyst works. The two processes help in the reaction of molecules to make them attract and attach to one another. Activated carbon is best, effective adsorbents for the purification or recovery of different chemicals. Turnover frequency usually expresses the efficiency of a catalyst. It is a chemical reaction rate and not a rate constant. Equation 15.1 is used for calculating the TOF of a catalytic process (Boudart 1995)

TOF = number of molecules of a given product /

(number of active sites) x(times) (15.1)

It is the best method of comparing the activities of different catalysts, however seldom used for the heterogeneous catalysts.

The ultimate product of an activation process of carbonaceous materials is acti­vated carbon with carbon contents in the range 72-90 %. The activation sequence generally commences with an initial carbonization of the raw material to obtain samples with high carbon content (Daza et al. 1986). Any organic material that is rich in carbon content but with low content in inorganic matter can be used as pre­cursor material for the preparation of activated carbon.

The seed accounts for 70 % weight of the fruit and is made of about kernel and husk (Singh et al. 2008). The seed is about 17.5 mm in length and 11.5 mm width and contains oil which is about 34 % of its total weight (Singh et al. 2008). The Jatrpoha fruit seeds have an energy value of 24 MJ kg-1, which is higher than coal (Augustus and Jayabalan 2002). Seed kernel represents 70 % of seed weight and has calorific value of 29.8 MJ kg-1 (Openshaw 2000) to 31.6 MJ kg-1 (Martinez — Herrera et al. 2006). J. curcas seed contains about 42 % seed husks. The seed husks contain 4 % ash, 25 % fixed carbon, and 71 % volatile matter (Vyas and Singh 2007; Singh et al. 2009). The seed husk has calorific value of 16 MJ kg-1 (Vyas and Singh 2007). Seed husks have a high bulk density (223 kg m-3) which makes them acquiescent to briquetting and hence an energy source. Syngas is obtained from J. curcas seed in an open core down draft gasifier (Vyas and Singh 2007).

Hydrolysis is the process to break down the pretreated cellulosic molecules into cellobiose, which is then further converted to simple sugar, such as glucose molecules and short chains. Hydrolysis can be carried out biologically through enzymatic reaction or chemically using acid.

20.3.2.1 Saccharification by Enzymatic Processes

One of the basic methods of hydrolysis is enzymatic hydrolysis. Enzymatic hydro­lysis occurs when enzymes are exposed to the pretreated biomass to decompose the cellulosic materials into simple sugars. Cellulose in nature is mostly decomposed by cellulolytic fungi and bacteria enzymatically. Some of the microbes that can produce cellulose enzyme are Trichoderma reesei, Trichoderma viride, and Aspergillus niger.

Enzymatic degradation of cellulose to fermentable sugar is generally accom­plished by synergistic action of high specific cellulose. This group includes at least 15 protein families and some subfamilies (Rabinovich et al. 2002). Enzymatic deg­radation of cellulose to glucose is generally accomplished by synergistic action of at least three major classes of enzyme: endocellulase, exocellulase, and p-glucosidase. These enzymes are usually called together cellulose or cellulolytic enzymes (Wyman 1996). To work, enzymes must obtain access to the molecules to be hydro­lyzed. Therefore, pretreatment process is needed to break the crystalline structure of the lignocellulose and remove the lignin to expose the cellulose and hemicellulose molecules.

The enzymes digest the lignin surface yielding cellulose. The endocellulase and exocellulase digest the cellulose into polysaccharide molecules. The polysaccharide molecules are then digested by the p-glucosidase yielding the final glucose product (Klass 2008). The reaction occurs around 40-50 °C and at a pH of about 5. Below, the figure demonstrates how the reaction path occurs.

However, enzymatic hydrolysis can be problematic. The hydrolysis products (glucose and cellulose chains) inhibit the ability for enzymes to convert cellulose to glucose. As more products are formed, the enzymes become more inhibited by the excess glucose present. This ultimately slows down the hydrolysis process yielding low levels of usable hydrolysis product (D’amore 1991). Another disad­vantage of using enzyme is the high enzyme cost. The enzyme cost takes a part as much as 53-65 % of total chemical cost, while the chemical cost is around 30 % of the total cost.

Enzymatic hydrolysis of lignocellulose is facing a number of obstacles that diminish the enzyme performance. Recently, although enzyme price has decreased due to intensive research by giant enzyme producers, such as Novozymes and Genencor, minimization of enzyme loading is still needed in order to reduce the production cost. Thus affecting the time needed to complete the enzymatic hydrolysis process. Furthermore, high substrate concentration increases the problem of product inhibition which also results in lower performance of the enzymes. Then, lignin presence in the substrate, which shields the cellulose chains and absorbs the enzymes, is also a major obstacle for efficient hydrolysis. Moreover, the activity of enzymes could be lost due to denaturation or degradation.

In this method, bamboo is pretreated with chemical substances to dissolve the lignin, glia, and hemi-cellulose and to weaken the binding force between fibers. The fibers are then formed by mechanical external force. Deshpande introduced a chem­ical mechanical processing system, which can extract the bamboo fiber. It combines traditional techniques to molding grinding processes. The extracted bamboo fiber can be used for processing of isotropic composite material. This method has low fiber rate, requires more chemicals, fiber has a certain pH, and the process is com­plex and costly (Yao and Zhang 2011; Deshpande et al. 2000).

The above-mentioned method of production of bamboo fiber can be used as strengthening method to make a variety of composite materials. The products are further developed, and bamboo fiber produced in these methods cannot be used for weaving (Yao and Zhang 2011).

Sugarcane area and productivity differ widely from country to country (Table 4.1). Brazil has the highest area. On the other side, Australia has the highest productivity. Out of 121 sugarcane producing countries, 15 countries (Brazil, India, China, Thailand, Pakistan, Mexico, Cuba, Columbia, Australia, USA, Philippines, South Africa, Argentina, Myanmar, Bangladesh) present 86 % of the area and 87 % of production (Table 4.1). Out of the total white crystal sugar production, approxi­mately 70 % comes from sugarcane and 30 % from sugar beet.

7.2.1 Proposal for Industrialization

A prototype model for the industrialization of A. comosus fiber was developed, based on the following principles: (1) it should be adaptable to the A. comosus leaf mor­phology; (2) the scale of production should be no more than 4 kg dried fiber/hour; (3) it should be portable, handled by three people, and transportable in a less than 2,000 cc engine pick up; and (4) it can be operated by staff with low training.

7.2.2 Testing Sites of the Model

The prototype machine was tested in four A. comosus plantations of the variety MD-2, two located in the North region and two in the South Pacific. All of the plan­tations had the same density with 70,000 plants/ha. In each region, the machine was tested with plants from the first crop (11 months old) and from the second crop (18 months old).

Bleaching type Description

The fiber was placed under running water at room temperature until it lost the green coloration given by the chlorophyll The fiber was put into a recipient with 250 ml of a hydrogen peroxide 5 % solution during 5 min. Then the fiber was washed under running water at room temperature

The fiber was introduced into a recipient with 250 ml of a hydrogen peroxide 1 % solution during 5 min. Next, it was washed under running water until the hypochlorite smell was lost

The hand lay-up technique is extensively used for natural fibre-thermosetting polymer composites for simple processing procedures. In this process, short fibres, unidirec­tional and woven fabrics can be fabricated in resin. The resins are laid on the fabric by using a roller. Sreekala et al. (2002) have prepared the short random oil palm/glass hybrid fibre-PF resin composites by very simple hand lay-up along with compres­sion moulding methods.

10.3.2.2 Vacuum-Assisted Resin Infusion Moulding

This method is used for making multilayer laminated composite. Unidirectional, nonwoven or woven mats are sized according to the shape of the mould chamber used in this process. The mould is set in between the resin container and pump. The resin and hardener are infused slowly for wetting mats by vacuum pump. Thereafter, curing is continued for a long time at ordinary temperature (Yuhazri et al. 2010).