Category Archives: Bioenergy

Okra Fibre as the Reinforcement for Thermosetting Polymers

Using unconventional plant fibres, such as okra, as the filler for conventional thermosetting matrices can be considered a preliminary step towards the fabrication of fully biodegradable composites. The use of thermosets enables a reflection on a

Category

Fibre type

Species

Cellulose (%)

Hemicellulose (%)

Lignin (%)

Source

Leaf

Sisal

Agave sisalana

56.5-78

5.6-16.5

8-14

Bledzki et al. (1996), Fuqua et al. (2012), Malkapuram et al. (2009)

New Zealand Flax

Phonnium Тепах

45.1-72.0

30.1

11.2

Carr et al. (2005), Fuqua et al. (2012), De Rosa et al. (2010b)

Abaca

Musa textilis

56-63

20.8

7-12.4

Fuqua et al. (2012), Mohanty et al. (2005), Sun et al. (1998)

Henequen

Agave fou rcroydes

77.6

4-8

13.1

Fuqua et al. (2012), Malkapuram et al. (2009)

Pineapple

Ananas comosus

70-82

15-19

5-12

Fuqua et al. (2012), Malkapuram et al. (2009), Saha et al. (1990)

Banana

Musa acuminata

63-64

10-19

5

Fuqua et al. (2012), Mohanty et al. (2005)

Bast

Flax

Liman usitatisshnum

71-81

18.6-20.6

2.2-3

Bledzki et al. (1996), Fuqua et al. (2012)

Hemp

Cannabis sativa

70.2-74.4

17.9-22.4

3.7-5.7

Bledzki et al. (1996), Fuqua et al. (2012)

Jute

Corchorus capsularis

61-73.2

13.6-20.4

12-16

Bledzki et al. (1996), Fuqua et al. (2012)

Ramie

Boehmeria nivea

68.6-76.2

13.1-16.7

0.6-1

Bledzki et al. (1996), Fuqua et al. (2012)

Okra

Abelmoschus esculentus

60-70

15-20

5-10

Arifuzzaman Khan et al. (2009), Shamsul Alam and Arifuzzaman Khan (2007)

Kenaf

Hibiscus cannabinus

31-57

21.5

8-19

Mohanty et al. (2005)

Table 11.1 Fibre constituent content

11 Okra Fibres as Potential Reinforcement in Biocomposites

Table 11.2 Decomposition temperatures for selected natural fibres (De Rosa et al. 2010a)

Table 11.3 Fibre mechanical properties

Category

Fibre type

Diameter

(pm)

Tensile

strength

(MPa)

Young’s

modulus

(GPa)

Source

Leaf

Sisal

50-200

80-640

1.46-15.8

Fuqua et al. (2012), Jayaraman (2003), Mishra et al. (2004)

Abaca

28

756

31.1

Shibata et al. (2002)

Henequen

180

500

13.2

Herrera-Franco and Valadez — Gonzalez (2005)

Pineapple

20-80

413-1,627

34.5-82.5

Mishra et al. (2004)

Curaua

9-10

913

30

Gomes et al. (2007)

Date palm

100-1,000

170-275

5-12

Al-Khanbashi et al. (2005)

Sansevieria

80-90

630-670

5-7.5

Munawar et al. (2006), Sreenivasan et al. (2011)

Bast

Flax

30-110

450-1,500

27.6-38

Arias et al. (2013), Barkoula et al. (2009), Malkapuram et al. (2009)

Hemp

53.7

690-873

9.93

Fuqua et al. (2012); Graupner et al. (2009)

Jute

25-200

393-773

2.5-26.5

Fuqua et al. (2012); Malkapuram et al. (2009)

Kenaf

43.3-140

223-624

11-14.5

Fuqua et al. (2012); Malkapuram et al. (2009)

Ramie

34

400-938

24.5-128

Angelini et al. (2000); Goda et al. (2006)

Okra

40-180

234-380

5-13

De Rosa et al. (2011); De Rosa et al. (2010a)

number of aspects. These include, for example, the possible maximum amount of fibres leading to an improvement of the composite properties, before effective impregnation gets hindered by an excessive amount of filler, and the evaluation of effectiveness of chemical treatment to provide a sounder fibre-matrix interface. It needs to be noted that plant fibre composites including kenaf fibres, which are botanically similar to okra, in thermosetting matrices are quite diffuse and a number of studies have been performed. In particular, it was demonstrated that alkali treat­ment with NaOH has some positive effect on fibre density and assists in improving the mechanical interlocking and chemical bonding between polyester resin and the

fibre, resulting in superior flexural and impact properties (Aziz and Ansell 2004). Another significant observation is that kenaf is very suitable to manufacture fabrics, therefore producing composites with a sufficiently high amount of fibres, compati­ble, e. g. with the requirements of the automotive industry as regards the envisaged substitution of fibreglass (Na and Cho 2010). It is not surprising, therefore, that fibres such as okra are having some minor interest for application in thermoset matrix composites.

In particular, unsaturated polyester matrix was reinforced with a maximum of 36 vol% okra fibres: the fibres were defined as “woven” in that the whole usable length of the stem, equal to around 60 cm, is employed to reinforce the composites (Srinivasababu et al. 2009). The fibres were introduced either without treatment or subjected to two different procedures, both including an alkali pretreatment with sodium hydroxide, followed by a long-time (14 h) or short-time (5 min) treatment with a very diluted acid solution of potassium permanganate (Srinivasababu and Rao 2009; Srinivasababu et al. 2009). Both treatments brought to some improve­ment of tensile modulus and especially to a more consistent increase of it with the introduction of a higher amount of fibres, which may depend on their more uniform geometry after treatment. In contrast, tensile strength only shows some improve­ment for the highest volume of fibres introduced (36 %), being reduced at lower volumes of reinforcement with respect to untreated okra fibre composites (Srinivasababu et al. 2009). Another study was performed on the introduction of a limited amount, up to 20 wt%, of okra fibres bleached with sodium hypochlorite, in a Bakelite matrix. Here, the introduction of fibres did not result in an increase of tensile and flexural strength with respect to the pure matrix, even for the maximum amount of fibre introduced and the situation was not substantially improved by bleaching, although this treatment did lead to an increased strength of the fibres alone (Moniruzzaman et al. 2009).

To summarize these results, the problems linked to the reduced interface strength and to the anomalous section of the okra fibres, as extracted from the bast, appear still limiting factors for possible applications as reinforcement for semi-structural components.

Gravity Sedimentation

Gravity sedimentation is a simple process used for the separation of algae in water and wastewater treatment, which is often supported by flocculation to upsurge the effectiveness of gravity sedimentation (Chen et al. 2011). Another model of gravity sedimentation procedure is flotation, which is considered more effectual and advan­tageous as compared to sedimentation and can capture the bits with thickness of less than 500 pm (Yoon and Luttrell 1989). The operative and efficient methods for harvesting of algal biomass include centrifugation and chemical precipitation (Chen et al. 2011). These procedures are not economically practicable for harvesting of algae due to high procedure charge of centrifugation or chemical flocculants for the production of biogas. Filtration also appears to have great prospective for condens­ing algal biomass from bulk culture, integration of different techniques such as floc­culation, gravity sedimentation, or flotation can also be done. For biogas production, concentrated slurry is considered as a good substrate for anaerobic digestion (Prajapati et al. 2012, 2013). The consumption of wet algal biomass reduces the water necessity, which is required in excessive amount for the digestion of conven­tional biomass, for biogas production.

Diluted Acid Hydrolysis

Dilute acid pretreatments can free hemicellulose and cellulose at moderate tempera­tures and disrupt the lignin through releasing the cellulose during the enzymatic reactions (Knappert et al. 1981; Yang and Wyman 2004) . Suhardi et al. (2013) reported that the highest ethanol production was obtained from 3 to 4 % sulfuric acid-treated biomass. The acid hydrolysis pretreatment and the enzymatic catalysis have been proved effectively for increasing the bioethanol production using both cellulose and pentose sugar fermenting recombinant E. coli; On the other hand, recombinant plasmids can be used to produce strains of Saccharomyces that are capable of fermenting sugars. Ho et al. (1998) reported that diluted acid hydrolysis was involved for the use of three xylose-metabolizing genes such as xylose reduc­tase, xylitol dehydrogenase, and xylulokinase, which was converted xylose to xyli — tol, xylitol to xylulose, and xylulose to xylulose-5-phosphate.

16.5.1.2 Fungal Pretreatment

The sugarcane straw with pretreatment of both fungi, Ceriporiopsis and Phanerochaete, has produced the maximum ethanol in 6 days of fermentation. The fungi such as brown rot and white rot fungi are capable of decomposing the fallen leaves naturally using trees and other plants for humic and water-soluble com­pounds (Lynn et al. 2010). These fungi produced different types of enzymes such as lignin peroxidase, phenol oxidase, manganese peroxidase, and laccase (Kuhad et al. 1997; Lenowicsz et al. 1999; Howard et al. 2003). Osma et al. (2007) reported that these fungi can produce enzymes under both submerged fermentation (SmF) and solid-state fermentation (SSF). Suhardi et al. (2013) reported that the solid — state fermentation pretreatment showed effective removal of lignin for higher etha­nol production from the fungal pretreated energy sugarcane compared to control treatment.

Steam Gasification for Hydrogen Production

Several scientific studies have been carried out using steam gasification for higher yield of hydrogen from different biomasses. Gil et al. (1999) have analyzed the effect of gasification agents on the product gas obtained from biomass gasification in fluidized bed using small chips of pine as biomass. Air, Steam-O2 mixture, and pure steam have been studied for hydrogen production. They conclude their results for hydrogen purity as follows in this order:

Pure steam (53-55 vol.%) > Steam-O2 (25-30 vol.%) > Air (8-10 vol.%)

Their results show that for hydrogen production the steam gasification is the best option. But on the other hand the steam gasification produced maximum tar yield compared to other gasification agents.

Franco et al. (2003) have studied the biomass steam gasification in fluidized bed reactor at atmospheric pressure. They operated gasifier with three different types of biomass, i. e., soft wood, hard wood, and globules. Temperature and steam/biomass were studied on the product gas composition, energy conversion, and higher heating value. They reported that both temperature and steam are in favor of more hydrogen yield. They predict that water gas shift is dominant in the biomass gasification with pure steam in the main five reactions of biomass gasification as follows.

Char gasification

C + H2O ® CO + H2

Boudouard

C + CO2 ® 2CO

Methanation

C + 2H2 ® CH4

Steam reforming

CH4 + H2O ® CO + 3H2

Water gas shift

CO + H2O ® CO2 + H2

They reported that the rise in temperature forecast increase in hydrogen and decreases in carbon monoxide. Furthermore, they also proved that hydrogen amount through biomass steam gasification is higher compared to pyrolysis. The maximum of hydrogen purity was obtained at 1,073 K and steam/biomass ratio of 0.5, i. e., 45 mol%.

Ahmed and Gupta (2009) studied experimentally both pyrolysis and steam gasification using paper as biomass within the temperature range of 873­1,273 K. They investigated the syngas flow rate, hydrogen flow rate, yield, and thermal efficiency of the product gas. They reported that hydrogen yield is much higher in gasification compared to pyrolysis. They obtained around 60 vol.% of hydrogen at 1,173 K. They reported that gasification process has advantage due to mainly char gasification reaction.

Weerachanchai et al. (2009) investigated the effect of steam gasification on the product gas composition using larch wood as biomass in fluidized bed reactor. Along with the temperature they also investigated the different types of bed materials. The maximum hydrogen was obtained at 1,023 K with 55.68 vol.%, 96 % of carbon conversion efficiency, 75.88 % cold gas efficiency, and 14.76 of lower heating value of product gas.

Umeki et al. (2010) have studied high temperature steam gasification process for hydrogen-rich product gas from wood as biomass. Both temperature and steam/car — bon ratio have been investigated on the product gas composition, carbon conversion efficiency, H2/CO ratio, cold gas efficiency, higher heating value, and total gas yield. In the experiment results they reported that the most dominant reaction is water gas shift reaction in steam gasification. The highest cold gas efficiency was predicted

60.4 % with the hydrogen of 55 vol.% at the outlet of the updraft fixed bed gasifier.

Date Palm Fibers

The date palm biodiversity is obvious all around the world where about 5,000 date palm cultivars can be found (Jaradat and Zaid 2004). Based on botanical descrip­tions, about 1,000 cultivars can be found in Algeria, 400 in Iran, 370 in Iraq, 250 in Tunisia, 244 in Morocco, and 400 in Sudan, as well as many additional cultivars in the other countries (Benkhalifa 1999; Osman 1983; Zaid and De Wet 1999). The date palm trees (Phoenix dactylifera L.) is the tallest Phoenix species, it can be found with heights of more than 30 m and has fruit reaching up to 100 mm x 40 mm in size. The fruits are very tasty and nutritious (Jaradat and Zaid 2004). Date palms have characteristics that adapt them to varied conditions. Date palm trees can grow well in sand, but it is not arenaceous. It can also grow well where soil water is close to the surface because they have air spaces in their roots. Although date palm tree can grow well in saline conditions, it can do better in higher quality soil and water. The leaves of the date palm are adapted to hot and dry conditions, but it is not a xerophyte and requires abundant water (Benkhalifa 1999; Jaradat and Zaid 2004).

The date palm tree is characterized by numerous offshoots produced at its trunk’s base. The trunk of the date palm tree is covered with persistent grayish leaf bases. It is surmounted by a handsome array of pinnate divided long leaves and needle sharp fronds. Usually, around 10-20 new leaves are produced annually. The leaves of the date palm are subtended by a cylindrical sheath of reticulate mass of tough, fibrous material, at their bases. These together form a tight protective envelope for the terminal bud (Benkhalifa 1999; Dakheel 2003). A young actively bearing date palm tree showing offshoots is shown in Fig. 1.2 and fruit of the date palm is seen in Fig. 1.3 . Detailed morphological traits of date palm tree leaf can be shown in Fig. 1.4. where different parameters of the leaf can be demonstrated like the leaf length, thickness, angle, length of leaflet part, rachis thickness, leaf lets number as well as others (Salem et al. 2008).

Once the date palms’ fruit are harvested, large quantities of date palm rachis and leaves wastes accumulated every year in agricultural lands of different countries. These amounts of important and valuable biomass wastes are of potential interest in different countries since they can be considered as new cellulosic fiber sources. Thus, innovative ways of valorizing this abundant renewable resource should be found (Chandrasekaran and Bahkali 2013). One of these ideas is to use such natural fibers in natural fiber composites suitable for different industrial applications. This can be one way of meeting the increasing demand in renewable and biodegradable materials. Therefore, the agricultural residues of date palms mainly rachis and leaves can be viewed as sources of reinforcing fibers for polymeric matrices in com­posite. The competitiveness of the date palm fibers in forming natural composites suitable for automotive industrial applications was demonstrated (Al-Oqla and Sapuan 2014). On the other hand, several studies proved that date palm fibers have the potential to be an effective filler in both thermoplastics and thermosetting mate­rials to be used in different industrial applications (Abdal-hay et al. 2012; Agoudjil et al. 2011; Al-Oqla and Sapuan 2014).

image2

Fig. 1.2 Date palm tree

image3

Fig. 1.3 Date palm fruit

Key to the diagram

image4Parameter Label

Подпись:Leaf length Leaf width Leaf angle Spinctcd part length Length of lcaflcted part Petiole width

Rachis thickness between the last spine and the first leaflet

Подпись:Leaf lets number

Terminal leaflet length

Terminal leaflet width

Ventral angle of middle leaflet

Middle leaflet width

Middle leaflet length

Leaflets spacing index at the middle

Angle of leaflets on both sides of

terminal one

Spine number SN

Middle spine width WS

Middle spine length LS

PW

Fig. 1.4 Detailed morphological traits of date palm tree leaf (Salem et al. 2008)

Date palm tree can produce annually large number of natural fibers that can be utilized in different industries. It is estimated that the annual date palm agricultural wastes are more than 20 kg of dry leaves and fibers for each date palm tree (Al-Oqla and Sapuan 2014). Moreover, the date palm tree produces another type of wastes as date pits which are about of 10 % of the date fruits (Barreveld 1993). Unfortunately, these agriculture wastes are not properly utilized in any biological process or industrial applications, in most of countries, despite of their contents of potential amount of cellulose, hemicelluloses, lignin, and other compounds. Typical date palm fibers can be seen in Fig. 1.5.

Textile Industry

Natural bamboo fibers have some of the excellent properties, which make it a very potent material to be used in textile industry. Refined bamboo fibers with low non — cellulosic content can be used in textiles (Liu et al. 2011). Bamboo fiber luster is closer to that of silk. It can be used for knitting and weaving purposes (Yi 2004). Study on bamboo fibers revealed that its chemical composition is same as that of all the bast fibers, which means cellulose content is in majority and lignin content is present in small amount. The structural properties of bamboo are different from those of other textile producing plants. Bamboo is shown to have high potential in textile industry (Yueping et al. 2010). They are used for the formation of socks, under wears, T-shirts, bathing suits, bathing suit cover ups, towels, Sleep wear, face masks, sani­tary napkins, bed sheets, pillows, baby diapers, bullet proof vests, table cloth, blinds, and mattresses. Bamboo fibers are observed to have excellent characteristics for spinning and weaving (Hengshu 2004). Dyeability of bamboo can be enhanced by plasma treatment. Longer the treatment time, higher the roughness and hence higher is the dyeability, which leads to increase in potential to be used as textile.

Current and Future Applications of Agricultural Biomass

Biodegradable/bio-based polymeric products is based on renewable plant and agri­cultural biomass as a basis for sustainable portfolio with eco-efficient products that can compete in markets, which currently dominated by petroleum-based products. Through intensive research and development, the large quantities of biomass have now found applications in commercially viable bio-based products. The utilization of lignocellulosic materials from biomass for a number of value-added products is very significant through chemical, physical and biological innovations to invent such innovative and competitive products in various fields, as shown in Fig. 5.9.

Sugarcane Straw and Bagasse

Rida Rehman and Alvina Gul Kazi

Contents

9.1 Introduction…………………………………………………………………………………………………….. 142

9.2 Green Management of Sugarcane……………………………………………………………………………. 142

9.3 Traits of Sugarcane Straw…………………………………………………………………………………….. 143

9.3.1 Straw Quality and Availability…………………………………………………………………… 143

9.3.2 Recovery of Straw and Its Final Use………………………………………………………….. 144

9.4 Agronomic Issues……………………………………………………………………………………………… 146

9.4.1 Erosion of Soil……………………………………………………………………………………… 146

9.4.2 Impact of Water…………………………………………………………………………………….. 148

9.4.3 Soil Stocks of Carbon……………………………………………………………………………… 149

9.5 Additional Impingement……………………………………………………………………………………… 151

9.6 Final Remarks…………………………………………………………………………………………………. 152

References…………………………………………………………………………………………………………… 153

Abstract For centuries now, sugarcane is being cultivated and is acting as a source of sugar production. This production is the source of many breeding programs all around the world. The sugarcane straw usually considered as trash is normally burned or is left in the soil depending on the harvesting system. There is an immense amount of straw being wasted yearly. Besides utilizing the straw for energy production or its requirement, there are a lot of other agronomic benefits that enhance the possibility of the straw blanket placed/left on the ground includ­ing protection of soil avoiding erosion, increasing organic ratio of content of car­bon in the soil, inhibition of growth of weed, recycling of nutrients in textile fiber, and soil water reduction. Although consumption of sugarcane is very popular worldwide, certain factors are to be kept in mind regarding postharvest storage of

R. Rehman • A. G. Kazi (*)

Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Islamabad, Pakistan e-mail: alvina_gul@yahoo. com

K. R. Hakeem et al. (eds.), Biomass and Bioenergy: Processing and Properties,

DOI 10.1007/978-3-319-07641-6_9, © Springer International Publishing Switzerland 2014 stalk that involves enzymatic browning. This chapter focuses on ways sugarcane straw can be utilized as a primary source for the production of products having great agronomic value. Balancing the pros of keeping sugarcane fields with a percentage of straw, which significantly outnumber the cons, economists are keen to find out beneficial properties and economic aspects of keeping straw on the ground rather than using it all as possible energy source. The most challenging factor is to main­tain the straw quality rendering it useful.

Keywords Sugarcane straw • Soil • Agronomic benefits • Energy • Carbon content

9.1 Introduction

For many centuries, sugarcane has been cultivated. Many breeding programs, all over the world, are driven by production of sugar that resulted in the so-called noble varieties of sugarcane being commercially used at present. Initially, a high value specialty, sugar has now gained laurel of being one of the cheapest calorie food due to immense and rigorous reduction in the cost of its production. Sugarcane is known to be a food crop of high yield. It has also been demonstrated as a splendid feed­stock for energy because of its high content of primary content per mg of cane. For whole sugarcane (140 kg of straw included; dry basis), higher heating value (HHV) is 7.4 GJ mg-1 of stalks of cane (which include moisture content up to 70 %), based on average quality of Brazilian cane. The amount of primary energy produced by energy products such as ethanol and bagasse is nearly 2.2 GJ mg-1 or less than 30 % (Leal 2007). Bagasse is the fibrous residue obtained from extraction of juice on industrial scale. Bagasse is consumed in the boiler mills in order to fulfill the energy demand of the mill. In the preharvest, the fibers in the leaves and tops of sugarcane known as straw or trash are normally burned. In the case of nonmechanized harvest­ing operations, i. e., manual harvesting, the cost of harvesting sugarcane is reduced by practices, which include burning of sugarcane in order to facilitate harvesting and transportation.

Due to certain agronomic, economic, and environmental reasons, mechanical operations have taken over the manual harvesting of sugarcane with dry leaves maintenance (straw) on the ground, in a system named as green cane management in Brazil.

Methods for the Estimation of Woody Biomass

12.6.1 Destructive Sampling-Based Biomass Estimation

Estimating the total biomass in forest ecosystems is challenging due to the difficulties associated with the assessment of carbon stocks below-ground. The above-ground biomass can be easily estimated with highest accuracy in most cases; however, the below-ground biomass estimation is still labour intensive and time consuming. To overcome these limitations, the destructive sampling approach was introduced. The first step in this method involves the chopping of selected trees within some definite plots or transects, and digging out their root systems in order to establish the bio­mass above — and below-ground with the highest possible accuracy. Further, the field inventory measurements are collected by making use of the tools such as diameter tapes, spring scales, clinometers, pruning saws and shears, shovels, measuring tapes, field data recording accessories and paper bags (Avitabile et al. 2008; Chidumayo 1997; Japanese International Cooperation Agency JICA 2005). In the following step, the segments of stems and branches are weighed first in wet form in the field itself and then in an oven dried form in the laboratory for different significant purposes (De Gier 2003; Nogueira etal. 2008). Up to this level of data analysis provides cumulative information about the biomass levels per tree (both above — and below-ground). To obtain the complete information in a broad way to the whole area of interest by destructive sampling approach, the Allometry equation is employed.

Homogeneous and Heterogeneous Catalyst

The rate of a chemical reaction changes due to the participation of heterogeneous catalyst. The product generally desorbs from the surface of the catalyst and diffuses away after the completion of reaction. The catalytic site determined the surface area of the catalyst and hence it is very critical and important. Adsorption and desorption are the two phenomena associated with the heterogeneous catalysts functions. The two processes help in the reaction of molecules to make them attract and attach to one another. Homogeneous catalysts are in the same phase as the reactants. When catalysis in a single liquid phases this type of catalyst is called homogeneous cataly­sis. Table 15.3 shows the comparison of main advantages/disadvantages of homoge­neous vs. heterogeneous catalysts. A main disadvantage of homogeneous catalysts is the problem of their recovery from the reaction medium because of its hygro­scopic nature along with its hazardous nature for the environment as compared to heterogeneous catalysts; this led to flourishing activity attempting to heterogenize homogeneous catalysts.