An Evaluation of Different Nonwoody and Woody Biomass of Gujarat, India for Preparation of Pellets—A Solid Biofuel

Energy Sources, Part A, 33:2078–2088, 2011

Copyright © Taylor & Francis Group, LLC

ISSN: 1556-7036 print/1556-7230 online

DOI: 10.1080/15567030903503183

An Evaluation of Different Non-woody and Woody

Biomass of Gujarat, India for Preparation of

Pellets—A Solid Biofuel

B. GAMI,1 R. LIMBACHIYA,1 R. PARMAR,1 H. BHIMANI,1

and B. PATEL1

1Abellon CleanEnergy Ltd., Research and Development, Bodakdev,

Ahmedabad, India

Abstract Agricultural residues and woody by-products are promising alternatives

to virgin wood fiber as an industrial feedstock. Residues are abundant, cheap, andtheir use will yield economic, as well as environmental, dividends. We must, however,

answer some pressing questions and take action before the full potential of thisfiber source can be realized. The present article attempts to evaluate 74 biomass for

proximate analysis, higher heating value, and feasibility for preparation of densifiedbio-pellet. Large-scale pellets production was performed from selected biomass as

a whole or in combination with other residues to achieve maximum combustiblestandards for any industrial application.

Keywords biofuel, biomass, biopellets, higher heating value, proximate analysis

1. Introduction

Agricultural residues and woody by-products are an excellent alternative to energy. The

advantages of using agricultural residues are three-fold: economic, environmental, and

technological. Aside from their abundance and renewability, using agricultural residues

will benefit farmers, industry, and human health and the environment. Using agricultural

residues for industrial purposes is a much more environmentally friendly practice than

many residue disposal methods currently in use. Until recently, many farmers disposed

of agricultural wastes by burning or landfilling them.

The search for suitable sources of biomass for generation of biofuels is actively

going on in different parts of the world. Biomass, being a renewable source of energy, is

seen as a long-lasting and sustainable solution to the energy crisis. In this context, every

country can look for the suitability of biomass depending upon its geographical position,

energy needs, and abundance of biomass. India is an agricultural country where different

states of India have different crop patterns as per different climatic conditions. In India,

Address correspondence to Dr. Beena Patel, Abellon CleanEnergy Ltd., Research and Devel-opment, Old Premchandnagar Road, Opp. Satyagrah Chhavani, Bodakdev, Ahmedabad 380054,India. E-mail: [email protected]

Rajendra Parmar and Ridhdhi Limbachiya are no longer with Abellon CleanEnergy Ltd.

2078

Dow

nloa

ded

by [

Bee

na P

atel

] at

10:

14 2

2 Se

ptem

ber

2011

Non-Woody and Woody Biomass for Pellets 2079

Figure 1. Overall process flow from biomass collection to production. (color figure available

online)

we have a lot of forest residue, agricultural residue, wild grasses, non-fodder crops, etc.,

which may be diverted to the biofuel program. But a thoughtful selection of the biomass

is required as it should meet all possible criteria for combustion as fuel.

Currently, both production and demand for wood pellets is increasing. Many indus-

tries are coming up with wood pellet plants (Gerold and Ingwald, 2004), and such activity

is emerging all over the world to sustain their energy security. Conversion of timber,

timber co-products, and agricultural residue into fuel pellets has become a major business.

However, one must be concerned for availability of continuous feedstock supply, cost of

feedstock, and quality of feedstock (www.glasu.org.uk). To the best of our knowledge,

many commercial firms and educational institutes in India have started working on this

subject now. In the present article, our attempt is to evaluate several agro-residue and

woody biomass for their potential as solid biofuel preparation and production of pellets at

small laboratory scale as well as large-scale industrial pellet mills as shown in Figure 1.

2. Experimental

1. All biomass were collected from their source place. Authenticity of the samples

were confirmed with the agricultural expert team of our R & D division. Ta-

ble 1 shows a list of the biomass samples and their parts used in the present

investigation.

2. The biomass were chopped in small pieces and kept in an oven at 105ıC overnight.

The next day the samples were cooled down in the atmosphere and subjected to

proximate analysis and high heating value (HHV).

Dow

nloa

ded

by [

Bee

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atel

] at

10:

14 2

2 Se

ptem

ber

2011

Ta

ble

1

Lis

to

fth

eb

iom

ass

use

din

pre

sen

tin

ves

tig

atio

n

No

.F

eed

sto

ckT

yp

es

Mo

istu

re,

%

VM

,

%

Ash

,

%

Cf

ix,

%

HH

V,

Kca

l/k

gP

elle

tp

ote

nti

al

1G

rou

nd

nu

tS

hel

l1

0.1

68

2.8

19

.14

,00

8G

oo

db

iom

ass,

low

ash

,av

aila

ble

inla

rge

qu

anti

ty.

2C

oco

nu

tS

hel

l3

65

.81

.23

04

,16

3G

oo

db

iom

ass,

low

ash

,h

ard

tocr

ush

top

ow

der

,av

aila

bil

ity

isp

oo

r.

3C

asto

rS

hel

l3

.66

9.9

4.6

21

.93

,72

7G

oo

db

iom

ass,

chea

pbu

tn

eed

com

bin

atio

nw

ith

oth

er

bio

mas

sto

imp

rov

ep

elle

tq

ual

ity.

4C

ott

on

Sh

ell

2.5

67

.94

.22

5.4

3,8

49

Go

od

bio

mas

s,ch

eap

,la

rge

qu

anti

tyav

aila

ble

bu

tn

eed

to

rem

ov

eco

tto

nfi

ber

sb

efo

rep

elle

tiza

tio

n.

5C

occ

oS

hel

l7

68

81

73

,82

4H

ard

tocr

ush

,n

ot

avai

lab

lein

larg

eq

uan

tity

.

6B

amb

oo

Lea

ves

7.7

68

.71

2.3

11

.33

,75

6V

ery

hig

has

h,

also

no

tav

aila

ble

inp

len

ty,

cru

shin

gis

ver

y

dif

ficu

lt.

7D

ate

pal

mL

eav

es6

.44

68

.39

.61

5.6

64

,13

3

8P

roso

pis

Lea

ves

47

9.8

2.3

31

3.8

75

,54

5G

oo

db

iom

ass

wit

hlo

was

h,

bu

tco

llec

tio

nin

larg

eq

uan

tity

isd

iffi

cult

.

9G

ard

enla

wn

Lea

ves

6.9

72

.63

.21

7.3

3,6

41

Go

od

bio

mas

s,fo

rco

llec

tio

nn

eed

stra

teg

yp

lan

nin

g,

chan

ces

of

con

tam

inat

ion

wit

ho

ther

bio

mas

san

dso

ilp

arti

als.

10

Su

gar

can

eL

eav

es8

.82

71

.56

8.7

10

.92

3,9

04

Hig

has

h,

qu

anti

tyav

aila

ble

bu

tal

sou

sed

info

rag

e.

11

Co

tto

nS

tem

7.5

70

.32

.51

9.7

3,9

91

Ver

yg

oo

db

iom

ass,

ple

nty

of

qu

anti

tyav

aila

ble

.

12

Pro

sop

isS

tem

7.7

78

.90

.51

2.9

4,2

37

Ver

yg

oo

db

iom

ass,

ple

nty

of

qu

anti

tyav

aila

ble

,h

arv

esti

ng

is

dif

ficu

lt.

13

Ty

ph

aS

tem

8.2

71

.44

.61

5.8

3,7

89

Bio

mas

sw

ith

low

ash

bu

td

ue

toh

yd

rop

hy

tes,

har

ves

tin

gan

d

avai

lab

ilit

yis

no

tg

oo

d.

14

Cas

tor

Ste

m2

0.5

63

.52

.11

3.9

3,4

96

Go

od

bio

mas

s,d

iffi

cult

tom

ake

pow

der

asst

emco

ver

ed

wit

hfi

ber

s,bu

lkd

ensi

tyis

low

.

15

Ipo

mea

Ste

m1

1.7

66

3.4

18

.93

,67

0G

oo

db

iom

ass,

avai

lab

ilit

yis

po

or,

bu

lkd

ensi

tyis

low

.

16

Su

nh

emp

Ste

m1

7.1

58

.74

.91

9.3

3,8

00

Go

od

bio

mas

s,av

aila

bil

ity

isp

oo

r.

17

Ses

ban

iaS

tem

14

.86

2.3

6.3

16

.63

,43

4G

oo

db

iom

ass,

avai

lab

ilit

yis

po

or,

bu

lkd

ensi

tyis

low

.

(co

nti

nu

ed

)

2080

Dow

nloa

ded

by [

Bee

na P

atel

] at

10:

14 2

2 Se

ptem

ber

2011

Ta

ble

1

(Co

nti

nu

ed)

No

.F

eed

sto

ckT

yp

es

Mo

istu

re,

%

VM

,

%

Ash

,

%

Cf

ix,

%

HH

V,

Kca

l/k

gP

elle

tp

ote

nti

al

18

Bri

ng

leS

tem

19

.25

0.9

11

.61

8.3

2,9

45

No

ta

go

od

bio

mas

sfo

rp

elle

t,st

emh

asst

ick

yn

atu

re,

and

cov

ered

wit

hse

nd

soil

.

19

To

mat

oS

tem

19

.45

4.1

11

.21

5.3

2,6

94

20

Cap

sicu

mS

tem

21

.45

17

.52

0.1

3,1

05

21

Su

Bav

alS

tem

9.8

74

0.5

15

.74

,01

8G

oo

db

iom

ass,

avai

lab

ilit

yis

po

or.

22

Per

ryg

rass

Ste

m1

5.6

59

.75

.61

9.1

3,4

77

No

ta

go

od

bio

mas

s,av

aila

bil

ity

isv

ery

po

or.

23

Ok

har

aS

tem

19

.55

9.2

9.8

11

.52

,95

3N

ot

ag

oo

db

iom

ass

for

pel

let,

stem

has

stic

ky

nat

ure

,an

d

cov

ered

wit

hse

nd

soil

.

24

Pu

wad

Ste

m6

.67

2.8

3.4

17

.24

,07

1G

oo

db

iom

ass.

Avai

lab

lep

len

tyin

fore

st,

con

tam

inat

ion

may

occ

ur

du

rin

gco

llec

tio

n.

25

Co

con

ut

Ste

m4

.65

68

.93

23

.45

3,4

88

Go

od

bio

mas

s,av

aila

bil

ity

isp

oo

r.

26

Pin

eS

tem

4.7

70

0.8

24

.54

,34

6G

oo

db

iom

ass

for

pel

lets

.

27

Ty

ph

aS

tem

7.5

75

11

.36

.23

,78

9B

iom

ass

wit

hh

igh

ash

and

du

eto

hy

dro

ph

yte

s,h

arv

esti

ng

and

avai

lab

ilit

yis

no

tg

oo

d.

28

So

rgh

um

Ste

m5

.38

69

.46

.41

8.8

23

,98

1B

iom

ass

go

od

for

pel

leti

zati

on

bu

tav

aila

bil

ity

isp

oo

ras

use

info

rag

e.

29

Pig

ion

pea

Ste

m1

2.4

66

.96

.61

4.1

4,1

02

Bio

mas

sg

oo

dfo

rp

elle

tiza

tio

nbu

tav

aila

bil

ity

isp

oo

ras

use

info

rag

e.

30

Mu

star

dS

tem

4.2

27

1.2

5.2

19

.38

4,1

48

Bio

mas

sg

oo

dfo

rp

elle

tiza

tio

n.

31

Bla

ckg

ram

Ste

m4

.96

8.2

3.5

23

.43

,91

6B

iom

ass

go

od

for

pel

leti

zati

on

,av

aila

bil

ity

ism

od

erat

eas

peo

ple

use

for

ho

use

ho

ldh

eati

ng

pu

rpo

se.

32

To

bac

coS

tem

3.4

71

6.8

18

.82

,79

6N

ot

ag

oo

db

iom

ass

for

pel

leti

zati

on

asd

ust

wh

ile

gri

nd

ing

stem

pro

du

ceal

lerg

icef

fect

.

33

Co

rien

der

Ste

m1

.57

1.2

3.6

23

.73

,67

3G

oo

db

iom

ass

for

pel

lets

.E

asy

tocr

ush

,bu

tp

rod

uce

typ

ical

smel

ld

uri

ng

bu

rnin

gan

dlo

wbu

lkd

ensi

ty.

34

Wh

eat

Ste

m0

.67

2.1

3.4

23

.93

,69

4B

iom

ass

go

od

for

pel

leti

zati

on

.B

ut

coll

ecti

on

isb

itd

iffi

cult

.

35

Wh

eat

Ste

mw

ith

hu

sk0

.67

0.1

4.3

25

3,6

61

(co

nti

nu

ed

)

2081

Dow

nloa

ded

by [

Bee

na P

atel

] at

10:

14 2

2 Se

ptem

ber

2011

Ta

ble

1

(Co

nti

nu

ed)

No

.F

eed

sto

ckT

yp

es

Mo

istu

re,

%

VM

,

%

Ash

,

%

Cf

ix,

%

HH

V,

Kca

l/k

gP

elle

tp

ote

nti

al

36

Ban

ana

Ste

m3

.57

2.6

4.6

19

.33

,47

4N

ot

ag

oo

db

iom

ass

for

pel

let,

har

dto

mak

ep

ow

der

and

dif

ficu

ltto

dry

,sm

ok

ew

hil

ebu

rnin

gp

rod

uce

alle

rgic

effe

ct.

37

Cu

min

Ste

m2

.67

33

.12

1.3

4,1

25

Go

od

bio

mas

sfo

rp

elle

ts.

Eas

yto

cru

sh,

bu

tp

rod

uce

typ

ical

smel

ld

uri

ng

bu

rnin

gan

dch

ance

so

fco

nta

min

atio

nw

hil

e

coll

ecti

on

asp

lan

tis

ver

ysm

all.

38

Co

con

ut

Hu

sk1

3.4

56

.72

.42

7.5

3,8

00

Go

od

bio

mas

sfo

rp

elle

ts.

Bu

tav

aila

bil

ity

isv

ery

po

or.

39

Ric

eH

usk

7.2

61

.81

6.4

14

.63

,72

9A

lth

ou

gh

ash

con

ten

tis

hig

hit

isv

ery

go

od

bio

mas

sfo

r

pel

leti

zati

on

du

eto

easy

han

dli

ng

.

40

Jatr

op

ha

DO

C7

.36

5.1

8.3

19

.34

,72

5G

oo

db

iom

ass

for

pel

lets

.B

ut

avai

lab

ilit

yis

ver

yp

oo

r.

41

Cas

tor

DO

C2

.46

8.9

4.2

24

.53

,94

5G

oo

db

iom

ass

for

pel

lets

.

42

Su

gar

can

eB

agas

se4

.57

7.1

2.4

16

4,5

47

Go

od

bio

mas

sfo

rp

elle

ts.

Bu

td

ue

tofi

bro

us

nat

ure

nee

d

spec

ial

care

inp

elle

tm

ill.

43

Ele

ph

ant

Bag

asse

11

.56

3.4

5.4

19

.73

,60

1V

ery

go

od

bio

mas

s,av

aila

bil

ity

isp

oo

r.

44

Dry

flow

erF

low

er1

0.7

66

.95

.21

7.2

3,9

50

Go

od

bio

mas

sfo

rp

elle

ts.

Bu

tav

aila

bil

ity

isv

ery

po

or.

45

Co

con

ut

Flo

wer

4.8

77

3.1

6.2

21

5.8

14

,37

7

46

Ty

ph

aF

low

er1

56

51

73

2,8

85

No

ta

go

od

bio

mas

sfo

rp

elle

t.

47

Wat

erh

yac

inth

Wh

ole

pla

nt

12

63

.82

13

.23

,77

1N

ot

ag

oo

db

iom

ass

for

pel

let.

48

Kan

jaru

Wh

ole

pla

nt

21

.74

8.4

13

.31

6.6

2,3

35

49

Pam

aro

saW

ho

lep

lan

t6

.67

2.7

4.4

16

.34

,24

4G

oo

db

iom

ass

for

pel

lets

.B

ut

avai

lab

ilit

yis

ver

yp

oo

r.

50

Saf

flow

erW

ho

lep

lan

t1

0.6

16

88

.91

2.4

95

,66

6

51

Pin

ed

ust

Saw

du

st9

.27

11

.51

8.3

4,1

06

Go

od

bio

mas

sfo

rp

elle

ts.

52

Saw

du

stty

pe

1S

awd

ust

10

.56

8.7

0.9

81

9.8

24

,07

5

53

Saw

du

stty

pe

2S

awd

ust

10

65

.81

.32

2.9

4,0

08

54

Saw

du

stty

pe

3S

awd

ust

12

70

.10

.51

7.4

3,1

01

(co

nti

nu

ed

)

2082

Dow

nloa

ded

by [

Bee

na P

atel

] at

10:

14 2

2 Se

ptem

ber

2011

Ta

ble

1

(Co

nti

nu

ed)

No

.F

eed

sto

ckT

yp

es

Mo

istu

re,

%

VM

,

%

Ash

,

%

Cf

ix,

%

HH

V,

Kca

l/k

gP

elle

tp

ote

nti

al

55

Saw

du

stty

pe

6S

awd

ust

11

.06

7.5

1.1

20

.43

,78

0G

oo

db

iom

ass

for

pel

lets

.

56

Saw

du

stty

pe

4S

awd

ust

86

9.5

0.4

52

2.0

53

,65

4

57

Saw

du

stty

pe

5S

awd

ust

12

68

.20

.38

19

.42

3,2

58

58

Car

ton

bo

xP

aper

1.2

75

.84

.91

8.1

3,8

59

Go

od

bio

mas

sbu

tg

rin

din

gan

dp

elle

tiza

tio

nis

dif

ficu

lt.

59

Pri

nte

dp

aper

Pap

er2

.27

6.4

5.8

15

.64

,34

4

60

Wo

od

chip

sW

oo

d7

.87

7.5

61

.47

13

.17

4,3

59

Go

od

bio

mas

s,bu

tg

rin

din

gis

req

uir

edfo

rp

elle

tiza

tio

n.

Fo

r

coll

ecti

on

stra

teg

yp

lan

nin

gis

req

uir

ed.

61

Mat

chst

ick

wo

od

Wo

od

6.4

47

9.6

0.3

13

.66

4,7

80

62

Ply

wo

od

Ou

ter

4.5

68

.15

1.6

62

5.6

92

,56

0

63

Ply

wo

od

Inn

er9

.09

68

.90

.71

21

.34

,64

3

64

Fir

ewo

od

Wo

od

25

.68

60

.73

.33

10

.29

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3. Ash content, fixed carbon (Cfix), moisture content, volatile mater (VM), and HHV

in the biomass were analyzed as described by James (2005).

4. All listed biomass were grinded to powder (3 mm) with a grinder and hammer

mill. Two kilograms of each biomass powder was subjected to pelletization by the

mini pellet mill and the well pelletized material was subjected to check feasibility

of production at a commercial scale.

2.1. Pelletization

The fuel pellet was manufactured by first processing the input material to reduce the size

to about 10 to 50 mm, by running through a shredder, where the input material size was

reduced so that about 60 to 70% of the material was about 20 to 30 mm, 15 to 20% of

the material was about 10 to 20 mm, and the remaining 15 to 25% of the material was

about 30 to 50 mm in size. The reduced input material was then dried using a three-pass

belt conveyor-type drier, where material was dried by hot air blown at temperatures from

about 100 to 200ıC. Moisture content of the dried material was from about 10 wt% to 12

wt%. Dried material was passed on to a hammer mill (RK Hammer Mill Model RKHM

125; R K Machines, Halol, Gujarat, India) to grind the material to about 2 to 3 mm. The

powdered material was conveyed to the batch mixer, and water was sprinkled as per the

requirement so as to moisten the material. The moist, well-mixed material was conveyed

to the pellet mill through a conditioner equipped with multi-point steam injection and an

adjustable paddle for mixing. Hot water or steam may be injected into treated material

at about 125 to 150ıC, the pellet mill (Inovo 52-14, R K Machines) having a die of

520 mm inner diameter, 140 mm width, and 50 holes of 6 mm diameter. The extruded

pellets were cut by an adjustable cutter assembly producing pellets of about 6 to 10 mm

diameter and about 6 to 20 mm length. The temperature of the extruded pellets was about

50 to 80ıC, pellets were air cooled in a counter flow cooler (Model RKM 18 � 18, R K

Machines), and then are passed through a screen before packing.

2.2. Batch Wise Production of Pellets

Eight batches of biofuel pellets (750 kilograms) were made using different input materials

as per the combinations described in Table 2 using a pelletization process. The input

material was weighed out and mixed in a mixer for about 3–5 min. The well-mixed

material was steamed and then pelletized. Pellets were cooled and screened to remove

any remaining fine material and were subjected to analysis (proximate analysis and HHV).

Table 2

Different combination of biomass selected for trial in large-scale batch-wise production

Wt%

Input

material Batch 1 Batch 2 Batch 3 Batch 4 Batch 5 Batch 6 Batch 7 Batch 8

Cotton stalk 100 0 0 0 0 50 00 00

Groundnut shell 0 100 0 0 0 00 50 00

Castor DOC 0 0 100 0 0 50 50 50

Saw dust type 2 0 0 0 100 0 00 00 00

Wood chips 0 0 0 0 100 00 00 50

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3. Results and Discussion

Worldwide photosynthetic activity is estimated to store 17 times as much energy as is

consumed annually by all nations in the world. Even if the energy required for collection,

processing, and conversion into other useful forms is taken into account, biomass still

holds the promise to meet the complete energy needs of the world, if managed and used

effectively and sustainably. To use these huge resources of energy in a systematic way, we

should know the proximate analysis and higher heating value of all feedstocks. Table 1

shows proximate analysis and higher heating value for 74 feedstocks available in Gujarat.

Gujarat has eight climatic zones with 112 lakh ha of total cultivated area. Different kinds

of pulses, cereals, fruits, horticultural, and many more crops are cultivated in Gujarat.

Millions of the agricultural residues are generated on a yearly basis, which could be

utilized for bioenergy (www.agri.gujaratgov.in).

Biomasses were screen for basic properties and palletized at lab scale. While per-

forming all processes from collection to pelletization, several observations were recorded

for each feedstock with large-scale production point of view (Table 1). Several biomasses,

such as perry grass, okhara, bringle, tomato, capsicum, banana stem, typha, and water

hyacinth, are not good candidates for the pellet preparation (Table 1). Among these

biomasses, typha and water hyacinth contain high amounts of ash at 17 and 21%,

respectively. The high ash content is not due to external contamination but because

of the absorption of several inorganic matters dissolved in water by their root systems.

These biomass are hydrophytes; therefore, collection and drying is quite difficult as

compared to other terrestrial land plants. Feedstocks, such as coconut shell, husk and

stem, jatropha DOC, elephant grass bagasse, pamarosa, safflower, and fermented fruit

residue, showed good HHV and proximate analysis value (Table 1), however, a constant

supply of these biomasses is questionable. Therefore, apart from high heating value,

constant availability is also a major concern to be considered before going for pellet

production.

For evaluating biomass materials for an energy generation point of view, useful prop-

erties like moisture content, ash content, and heat of combustion (HHV) are important.

Among these, ash content and its elemental analysis are the most significant parameters to

solve potential technical problems like reactor slagging and pollution problems (Domalski

and Milne, 1985). The ash content of woody biomass without bark is, in general, below

1%. In contrast, fast growing biomass has an ash content up to 20% or more. All fast

growing herbaceous biomass, such as straw, hay, leafs, etc., contain about an order of

magnitude more ash than wood. Higher ash and concentrations are also an indication

of higher fertilizer requirements for the faster growing species (Henrich and Weirich,

2004). In the present investigation, very low ash content was found in wood and saw

dust (Table 1). It is depicted from Table 1, that among woody biomass, ash content ranges

from 0.3% (match stick wood) to 3.58% (ply wood); these could be due to the external

contamination of some inorganic material or binding agent.

The distribution of ash and specific inorganic components in herbaceous biomass may

vary significantly among different plant fractions. Summers et al. (2001) determined total

ash and silica in different botanical fractions of rice straw (leaf, stem, node, panicle) and

concluded that ash and silica content varied significantly among straw fractions: leaves

contained 18–19% total ash, whereas stems only contained 12% ash. Distribution of

inorganic constituents among plant parts is often specific and can have a direct impact

on the application of the biomass type. Similar variations in ash % were observed

in coconut shell, flower and stem, sugarcane leaves and bagasse, and typha leaves

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and flower (Table 1). High ash levels will also be a problem if a portion becomes

fly ash that can foul flues and heat exchangers (www.glasu.org.uk). Ash content also

influences the choice of the appropriate combustion technology, deposit formation, fly

ash emissions, logistics concerning ash storage and ash utilization/disposal (Ingwald et al.,

2006).

Moisture content also affects the quality of the pellets; biomass with high moisture

content directly influences the production cost as a dryer was employed before pelleti-

zation (Gerold and Ingwald, 2004). Feedstock with high moisture content are not good

candidates for pelletization. Same way volatile matter has a significant impact for end

use of pellets to select proper combustion technology. Biomass with high volatile gases

is easy to ignite with smoke while with low volatile value biomass can be burnt cleanly

(http://www.fao.org/docrep/X5555E/x5555e03.htm). Like volatile matter, fixed carbon is

also important to select combustion technology for end users. The fixed carbon content is

the most important constituent in metallurgy since it is the fixed carbon that is responsible

for reducing the iron oxides of the iron ore to produce metal (http://www.fao.org/docrep/

X5555E/x5555e03.htm), and before selection of fuel for a furnace, fixed carbon of the

selected fuel is always measured.

Out of 74 biomass, all woody biomass are the best materials for large-scale pelleti-

zation. But in a bio-based economy like India, renewable herbaceous biomass, such as

straw and perennial grasses, will become important cellulosic feedstocks for conversion to

biofuels, chemicals, electricity, and heat. These biomasses contain some amount of heat as

mentioned in Table 1, it is lesser than the woody biomass but they are available in plenty.

Now combustion is commercially available and proven technology for converting biomass

to energy; however, improvements are continuously being made in fuel preparation and

combustion technologies as a result of demand to utilize new or uncommon fuels, improve

efficiencies, minimize costs, and reduce emissions (ECN, 2004). Properties of analysis

of herbaceous materials in Table 1 can be useful to prepare a ration of biomass with coal

during co-firing. The co-firing with biomass pellets technology has been demonstrated

at commercial scales in many system configurations, however, there are only a few

commercialized preparation and handling systems. The fuel preparation, storage, and

handling are the major technical challenges associated with biomass co-firing (Baxter,

2005; Jarvinen and Alakangas, 2001).

However, nearly all kinds of lignocellulosic biomass feedstocks fall in the range of

15–19 MJ/kg, which is correlated in this study. In the present investigation, range of

HHV was found to be from 2,335 to 5,666 kcal/kg. Furthermore, all values for most

woody materials are 4,059–4,537 Kcal/kg and for most agricultural residues, the HHV

are about 3,582–4,059 Kcal/kg (Ebeling and Jenkins, 1983). Woody biomass in present

investigation, such as all types of saw dust, wood chips, and all types of woody materials,

shows HHV � 4,000 Kcal/kg (Table 1).

Eight batches of selected biomass, such as cotton stalk, groundnut shell, castor doc,

sawdust type 2, and wood chips, were prepared as mentioned in Table 2. Pellets prepared

out of these selected biomass were analyzed for proximate analysis and HHV (Table 3).

HHV of pellets prepared from cotton stalk, groundnut shell, castor doc, sawdust type 2,

and wood chips did not much differ as compared to HHV analysis in raw form. Pelleting

itself does not change the calorific value of any material. It merely puts the material in a

different physical form with higher density, better storage, handling, and transportation

characteristics. However, if in the front end stock preparation, moisture is removed by

dryers, the calorific value is improved since this value is directly related to the moisture

content of the material.

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Table 3

Different parameters analyzed for pellets produced in each batch

Wt%

Parameter Batch 1 Batch 2 Batch 3 Batch 4 Batch 5 Batch 6 Batch 7 Batch 8

Moisture, wt% 8.1 5.2 5.7 7.3 9.0 6.6 9.7 10.1

Ash, wt% 2.44 0.98 4.3 0.54 0.5 0.71 1.2 1.5

Volatile matter, wt% 68.2 64.5 68.0 67.5 67.2 68.2 67.1 68.12

Fixed carbon, wt% 21.26 29.32 22.0 24.66 23.3 24.49 22.0 20.28

HHV, Kcal/kg 4,126 4,200 4,056 4,238 4,098 4,231 4,100 4,209

Mostly the wood- and straw-based pellets burn well, while other agricultural/food

co-products are harder to ignite and burn with greater difficulty, but a mixture of a

proportion of, per say, de-oiled cake with wood or other materials burns well. Pellets

produced in each batch were analyzed for proximate analysis and HHV (Table 3); results

represent more or less the same in respect of raw material value and good quality.

4. Conclusion

The present evaluation of 74 biomasses has shown that it is technically possible to produce

pellets from a range of alternative materials. But there may be issues associated with the

ash, moisture, and calorific value, so that one has to ensure before pelletization and

commercialization for particular targeted end users. The proper combination of biomass

is advisable to manage the quantity and quality of feedstock for continuous production.

There is a limited amount of wood-based raw material, however, with a combination of

different biomass based on different heating values and characteristics, one can produce

compatible pellets.

References

Baxter, L. 2005. Biomass-coal co-combustion: Opportunity for affordable renewable energy. Fuel

84:1295–1302.

Domalski, E. S., and Milne, T. A. 1985. Thermodynamic Data for Biomass Materials and Waste

Components. New York: The American Society of Mechanical Engineers.

Ebeling, J. M., and Jenkins, B. M. 1983. Physical and chemical properties of biomass fuel. American

Society of Agricultural Engineers, Winter Meeting, Chicago, Illinois, December 13–16.

ECN. 2004. Biomass pre-treatment and feeding. Available from http://www.ecn.nl/biomassa/

research/central/pretreatment.en.html

FAO. 2009. Wood carbonization and product it yields. Available from www.fao.org (accessed on

October 3, 2009).

Gerold, T., and Ingwald, O. 2004. Wood pellet production costs under Austrian and in comparison

to Swedish framework conditions. Biomass & Bioenergy 27:671–693.

Glasu. 2009. An investigation of the feasibility of preparing fuel pellets from a range of agricultural

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An Evaluation of Different Nonwoody and Woody Biomass of Gujarat, India for Preparation of Pellets—A Solid Biofuel

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