generate power from-biomass

THINK ABOUT BIOMASS FOR POWER

SOURCES, CLASSIFICATION, CHARACTERISTICS, PROPERTIES, CRITERIA FOR CHOOSING TREE SPECIES

FOR ENERGY PLANTATIONS

BIOMASS CONVERSION METHODS

WOODY Agro AQUEOUS WASTE

IMPORTANCE OF ENERGY SOURCES

INCREASING POPULATION WITH

INCREASED PER CAPITA ENERGY CONSUMPTION

FOR

AGRICULTURAL ACTIVITIES ,TRANSPORT, INDUSTRY AND PRODUCTION OF ELECTRICITY

INCREASES THE DEMAND FOR ENERGY

THERE IS NEED FOR USING NON-FOSSIL SOURCES OF ENERGY

INCREASED PER CAPITA ENERGY CONSUMPTION

AS POPULATION HAS INCRESAED RAPIDLY

3

1965 - 2005

AT PRESENT, WE DEPEND MOSTLY

ON COAL, OIL AND NATURAL GAS (FOSSIL FUELS).

THERE IS NEED FOR USING NON-FOSSIL SOURCES OF ENERGY

5

At present, nuclear, wind and hydro are the

dedicated non-fossil fuel sources of energy that

contribute to electricity generation; supplementing

coal [major role], natural gas and oil. Contribution of

biomass is small.

What is the role of biomass in electricity generation at present?

• At present, nuclear, wind and hydro are the non-fossil fuel sources of energy that are fully used for electricity generation supplementing coal [major contributor], natural gas and oil.

• Where cane sugar industry is thriving, with bagasse as fuel, electricity is produced along with process steam for the sugar industry.

• Contribution of biomass gasification with combined cycle or micro-gas turbine for power is yet to be fully established.

6

7

Change projected over a period of about twenty years.

The social, economic and environmental benefits of biomass

power are accepted for long term sustainability. The technologies

are progressively getting upgraded, attaining maturity, and

reaching commercialization. This is one of the renewable sources.

biomass

2002 to 2030

Two recently published renewable energy text /

reference books

Available in India

(see next slides)

Reference book Chapters

12 to15

10

The Energy and Resources Institute (TERI)

Another Reference book: Chapter 4 & 5

Fundamentals of Renewable Energy Sources

By

G. N. Tiwari and M. K. Ghosal

Narosa Publishing House, N.D. 2007

Chapter 4: Biomass, Biofuels and Biogas

Chapter 5: Biopower

11

What does it take to produce energy from biomass?

Route

From BIOMASS to ENERGY

Route From BIOMASS to ENERGY

13

What does it take to produce energy from biomass?

• Input for producing biomass: Seed, Land with soil, water, N P K + minor nutrients, sunlight and [manual + animal energy].

• How to Make it a usable Fuel: Biomass Residue from other uses maybe used as biofuel for combustion [heat-> Engine] or may be converted by conversion methods into derived S/L/G biofuel

• End use conversion devices: Thermodynamic cycles, Stoves, kilns, furnaces, steam turbines, gas turbines, engines and electricity Generators.

14

BIOMASS UTILIZATION

15

Environment Impact Assessment scope

16

17

Discuss a set of factors that explain the slow

growth on the biomass utilization.

They include:

1. High costs of production

2. Limited potential for production

3. Lack of sufficient data on energy

transformations coefficients.

4. Low energy efficiency

5. Health hazard in producing and using biomass.

23

Biomass conversion technologies

A number of modern biomass conversion

technologies are now available, which allow for

conversion of biomass to modern energy forms

such as electricity or gaseous (biogas, producer

gas), liquid (ethanol, methanol, fatty acid methyl

ester), and solid (biomass briquette) fuels.

Biomass conversion technologies can help in

meeting different types of energy needs,

particularly electricity. Key technologies for

power generation that have been promoted in

India are gasification, combustion,

cogeneration and biomethanation.

Technology specific incentives by MNRE

• Improved cook stoves: Central government subsidy is provided in the range of Rs. 80- to Rs. 150- per fixed model cook stove and Rs. 50- to Rs. 75- per portable cook stove. There are incentives for construction and maintenance, dealership support, support for publicity, technical backup and training.

• Biogas: A central subsidy of up to Rs. 6000- per plant for family-size biogas plants. Rs. 44,000 to 200,000 for community biogas plants. Rs. 44,000 to 150,000 for institutional biogas plants and concessional loans are made available through various schemes. The financial incentives (grants) are in the range of Rs. 2,000- to 3,000 – per cubic meter for large biogas plants. Incentive is also provided for operation and maintenance. Thus the government meets a significant part of the cost of the community biogas plant.

25

Technology specific incentives by MNRE

Biomass Gasifiers: Capital subsidy up to 60 % of the cost of a biomass gasifier and additional incentives up to 100 % are made available for selected components of village electrification projects. Additional incentives are also available for selected sited and other components. Soft loans are extended through IREDA for the remaining costs.

Biomass / bagasse co-generation: Capital subsidy of Rs. 4.5 million/ MW subject to a maximum of Rs. 81 million per project for demonstration projects in the joint venture or independent power producer (IPP) mode in co-operative / public sector sugar mills; soft loans (1% to 3% interest subsidy on loans) for commercial projects is provided by the MNES.

Source: MNES 2001; Note 1US$ = Rs. 40- in 2002

26

What is Biomass? What are its sources and how are

they classified?

BIOMASS • Biomass is material derived from plant and

animal sources.

• Products of Forestry, Agriculture, Urban and Industrial Waste Disposables are sources of biomass that may be converted into biofuels.

28

Sources of biomass

Primary:

• Forestry-Dense, Open;

• Social Forestry

• Agriculture,

• Animal Husbandry,

• Marine

Secondary:

• Industry,

• Municipal Waste

30

32

Technological advancements in biomass energy conversion:

• This comes from three sources – (1) enhanced efficiency of biomass energy conversion technologies, (2) improved fuel processing technologies and (3) enhanced efficiency of end-use technologies.

• Versatility of modern biomass technologies to use variety of biomass feedstock has enhanced the supply potential. Small economic size and co-firing with other fuels has also opened up additional application.

Classification of biomass based on physicochemical properties:

• WOODY,

• NON-WOODY or AGRO RESIDUE (cultivated),

• WET [AQUEOUS] ORGANIC WASTE (effluents)

34

Forests

Discuss forests as multifunctional natural resource that can also yield

woody biofuel.

Forest resource base-India

• 1 % of World's forests on 2.47 % of world's geographical area

• Sustaining 16 % of the world's population and 15 % of its livestock population

• Forest area cover—63.3 mill. hectares, is 19.2% of the total geographical area of India.

37

Causes of tremendous pressure on Forest resource base

• Exponential rise in human and livestock population

• increasing demand on land allocation to alternative uses such as agriculture, pastures and development activities.

• Insufficient availability, poor purchasing power of people in rural areas for commercial fuels like kerosene & LPG drives poor people to use firewood inefficiently as a cooking fuel.

38

• A minimum of 33 % of total land area under

forest or tree cover from present 19.2%

cover.

•Recognize the requirements of local people

for timber, firewood, fodder and other non-

timber forest produce-- as the first charge on

the forests,

• The need for forest conservation on the

broad principles of sustainability and

people’s participation.

The National Forest Policy

39

15.5 m. ha of degraded forest land has natural root

stock available, which may regenerate given proper

management under the JFM

•Another 9.5 m. ha is partially degraded with some

natural rootstock, and another six m. ha is highly

degraded. These last two categories together

constitute another 15.5 m. ha, which requires

treatment through technology-based plantation of

fuel, fodder and timber species with substantial

investment and technological inputs.

Joint Forest Management system.

40

• Fuelwood and fodder plantations to meet

the requirements of rural and urban

populations.

•Plantations of economically important

species (through use of high-yielding clones)

on refractory areas to meet the growing

timber requirement.

• Supplementing the incomes of the tribal

rural poor through management and

development of non-timber forest products.

The emphasis will be on:

41

• Developing and promoting pasture on suitable

degraded areas.

• Promoting afforestation and development of

degraded forests by adopting, through micro-

planning, an integrated approach on a watershed

basis.

• Suitable policy initiatives on rationalization of tree

felling and transit rules, assured buy-back

arrangements between industries and tree

growers, technology extension, and incentives like

easy availability of institutional credit etc.

The emphasis will be on cont…

42

To sum up, tropical India, with its adequate

sunlight, rainfall, land and labour,

is ideally suitable for tree plantations.

With the enhanced plan outlay for

forestry sector and financial support

from donor agencies, the country will

be able to march ahead towards the target

of 33 percent forest cover.

Forestry in the New Millenium:

43

What are agro-forestry, ‘trees-outside-forests [T o F]’ and

Energy Plantation?

Other than Forests we have thinner sources of trees.

44

Integrates trees with farming, such as lines

of trees with crops growing between them

(alley cropping), hedgerows, living fences,

windbreaks, pasture trees, woodlots, and

many other farming patterns.

Agro-forestry increases biodiversity,

supports wildlife, provides firewood,

fertilizer, forage, food and more, improves

the soil, improves the water, benefits the

farmers, benefits everyone.

Agro-forestry

45

46

agroforestry - A dynamic, ecologically based

natural resources management system that,

through the integration of trees in farmland and

rangeland, diversifies and sustains production for

increased social, economic and environmental

benefits for land users at all levels. Agroforestry,

the intercropping of woody and non-woody plants,

although age-old in practice, has now established

itself as a new science.

Energy Plantation: Growing trees for their fuel

value

• ‘Wasteland’-- not usable for agriculture and cash crops, useful for a social forestry activity

• A plantation that is designed or managed and operated to provide substantial amounts of usable fuel continuously throughout the year at a reasonable cost-- 'energy plantation'

48

Criteria for energy plantation-1

• 'Wasteland‘--sufficient area, not usable for agriculture and cash crops, available for a social forestry activity

• Tree species favorable to climate and soil conditions

• Combination of harvest cycles and planting densities that will optimize the harvest of fuel and the operating cost--12000 to 24000 trees per hectare.

49


• Multipurpose tree species-fuel wood supply & improve soil condition

• Trees that are capable of growing in deforested areas with degraded soils, and withstand exposure to wind and drought

• Rapid growing legumes that fix atmospheric nitrogen to enrich soil

50


• Species that can be found in similar ecological zones

• Produce wood of high calorific value that burn without sparks or smoke

• Have other uses in addition to providing fuel -- multipurpose tree species most suited for bio-energy plantations or social forestry

51

Give examples of trees suitable for Indian climatic zones

Fast growing nitrogen fixing trees that can withstand arid wasteland

Indian TREES / WOOD:

• Leucaena leucocephala (Subabul)

• Acacia nilotica (Babool)

• Casurina sp

• Derris indica (Pongam)

• Eucalyptus sp

• Sesbania sp

• Prosopis juliflora

• Azadiracta indica (Neem)

53

Forage legume = vegetable,

• Regeneration of earthworm populations in a

degraded soil by natural and planted fallows under

humid tropical conditions

• Use of Leucaena leucocephala: Fodder,

fuelwood, erosion control, nitrogen fixation,

alley cropping, staking material

• Ntrogen fixation legume: Due to Leucaena

leucocephala crop wasteland is reclaimed

Leucaena leucocephala Crop Use:

54

55

neem tree (Azadirachta indica)

Tree used in windbreaks, fuel wood plantations, and silvo-pastoral systems, for dry zones and infertile, rocky, sandy or shallow soils. The leaves, bark, wood and fruit of the neem tree either repel or discourage insect pests, and these plant parts are incorporated into traditional soil preparation, grain storage, and animal husbandry practices.

Several neem-based biological pest control (BPC) products have been developed. The neem tree can provide an inexpensive integrated pest management (IPM) resource for farmers, the raw material for small rural enterprises, or the development of neem-based industries.

56

JATROPA CURCAS [PHYSIC NUT]

Jatropha curcas [ physic nut], is unique among

biofuels. Jatropha is currently the first choice for

biodiesel. Able to tolerate arid climates, rapidly

growing, useful for a variety of products,

Jatropha can yield up to two tons of biodiesel fuel

per year per hectare.

Jatropha requires minimal inputs, stablizes or even

reverses desertification, and has use for a variety of

products after the biofuel is extracted.

57

Jatropha, continued

What makes Jatropha especially attractive to India is that it is a drought-resistant and can grow in saline, marginal and even otherwise infertile soil, requiring little water and maintenance.

It is hearty and easy to propagate-- a cutting taken from a plant and simply pushed into the ground will take root. It grows 5 to 10 feet high, and is capable of stabilizing sand dunes, acting as a windbreak and combating desertification.

58

Acacia nilotica: babul

A useful nitrogen fixing tree found wild in the

dry areas of tropical Africa and India

plantations are managed on a 15-20 year

rotation for fuel wood and timber.

calorific value of 4950 kcal/kg, making

excellent fuel wood and quality charcoal. It

burns slow with little smoke when dry

The bark of ssp. indica has high levels of

tannin (12-20%)

59

Pongam pinnata

A nitrogen fixing tree for oilseed

Also called as Derris indica, karanga,

Produces seeds containing 30-40% oil.

is a medium sized tree that generally attains

a height of about 8 m and a trunk diameter of

more than 50 cm

natural distribution of pongam is along coasts

and river banks in India and Burma

60

HYDROCARBON PLANTS, OIL PRODUCING SHRUBS:

• Hydrocarbon-- Euphorbia group

• & Euphorbia Lathyrus

• OIL Shrubs-- Euphorbia Tirucali

• Soyabean

• Sunflower

• Groundnut

• Jatropa

Discuss Properties & characteristics of

biomass

Wood – Agro residue – aqueous Waste

Properties of Solid Biomass :

62

Chemical Composition of Solid Biomass :

• Total Ash %,

• Solvent soluble %,

• Water Soluble %,

• Lignin %,

• Cellulose %,

• Hemi-cellulose %

63

Elemental Composition:

• Carbon

• Hydrogen

• Oxygen

• Nitrogen

• Sulphur

64

Properties of Wet and Biodegradable biomass:

• C O D value

• B O D value

• Total dissolved solids

• Volatile solids

65

What intervention is needed in traditional and primitive

rural utilization of biomass as fuel?

By overcoming poor purchasing power for LPG /Kerosene [to eliminate biofuel]

and investing in Energy Plantations

Make biofuel use economical and use efficient with new technology.

Problems in use of bio-fuels

Traditional biomass use is characterized by

• low efficiency of devices, scarcity of fuelwood, drudgery associated with the devices used,

• environmental degradation (such as forest degradation) and low quality of life.

67

68

• In the twenty-first century, energy is not as it

always was.

• Yesterday’s world was entirely dependent on

biomass, particularly wood for heating and

cooking.

• A century ago biomass was eclipsed by fossil

fuels. Biomass is generally viewed with disfavor

as something associated with abject poverty.

• Yet there is another side to biomass; there is

now something of a resurgence going on. As

fossil fuel prices increase, biomass promises (?)

to play a more active role as a utility fuel, a motor

vehicle fuel, and a supplement to natural gas.

Rural India & ‘bio-energy’ • Before the advent of fossil fuels, energy needs for all activities

were met by renewable sources such as solar, biomass, wind, animal and human muscle power.

• In rural India, traditional renewables such as biomass and human and animal energy continue to contribute 80 % of the energy consumption [MNES, 2001].

69

Share of bio-energy in primary energy consumption in India

In India, the share of bio-energy was estimated at

around 36 % to 46 % of the total primary energy

consumption in 1991 [Ravindranath and Hall, 1995], and has

come down to around 27 % in 1997 [Ravindranath et al.,

2000].For cooking, water heating and village industry,

use of firewood may have been substituted by LPG,

kerosene and diesel. Though availability has improved,

now prices are increasing. Improved cook stoves?

70

71

Eliminate excess use of fuel wood as rural Heating and

cooking Fuel: Fuelwood accounts for 60% of the total fuel

in the rural areas. In urban areas, the consumption pattern

is changing fast due to increased availability of commercial

fuel (LPG, kerosene, and electricity). During 1983–1999, the

consumption of traditional fuel declined from 49% to 24%

and LPG connection to households increased from 10% to

44%. Developments in the petroleum sector facilitate the

availability of (subsidized) LPG and kerosene, the two most

important forms of energy preferred as substitutes for

fuelwood in households for cooking.

72

Commercial fuel =

(LPG, kerosene, and

electricity).

What are modern bioenergy technologies, barriers to their

development and what programmes are needed?

Biomass conversion to usable fuels and the end use devices are to be

developed and marketed

76

India has over two decades of experience of implementing

bioenergy programmes. The Ministry of Non-conventional

Energy Sources (MNES or MNRE), the prime mover of the

programmes in India, has now responded with a

comprehensive renewable energy policy to give a

further fillip to the evolving sector. The need for climate

change mitigation provides an opportunity for promoting

the renewable energy (RE) sector. This calls for an

assessment of the policy barriers to the spread of

bioenergy technologies (BETs) in India.

77

• The experience shows that despite several financial

incentives and favourable policy measures, the rate of

spread of BETs is low because of the existence of

institutional, technical, market and credit barriers.

• These barriers are by and large known, but what still

remains to be understood is the type and size of barriers

from the stakeholders’ perspective, which varies for a

given technology and the stakeholder.

• Policy options suggested to overcome such barriers

include:

78

Bioenergy technologies : Remove Barriers:

(1) rational energy pricing: Explain the withdrawal of subsidy to Oil &

Gas products from economic & environmental point of view.

(2) Incentives for bioenergy to promote private sector participation,

(3) institutions to empower and enable community participation,

(4) financial support for large-scale demonstration programmes and for

focused research and development on bioenergy technologies

(BETs) for cost reduction and efficiency improvement, and finally,

(5) favourable land tenurial arrangements to promote sustained

biomass supply.

The global mechanisms for addressing climate change such as the

Clean Development Mechanism (CDM) and the Global Environment

Facility (GEF) provide additional incentives to promote BETs.

•Offer opportunities to conserve biomass

through efficiency improvements, and for

conversion to electricity and liquid and

gaseous fuels.

• Bio-energy technologies based on

sustained biomass supply are carbon

neutral and lead to net CO2 emission

reduction if used to substitute fossil fuels.

Modern Bio Energy Technologies

79

80

Bio Energy Technologies and their products

Thermo-chemical production of fuels from Biomass

Pyrolysis, Gasification and Catalytic conversion

( Techno-economic development is a research area for these technologies)

Biomass Fast Pyrolysis to Transportation Fuels

• Biomass fast pyrolysis is a thermochemical process that

converts feedstock into gaseous, solid, and liquid products

through the heating of biomass in the absence of oxygen.

• The liquid is called ‘Bio-oil’ and can be upgraded as a usable fuel

for an engine. A techno-economic study of transportation

biofuels via fast pyrolysis and bio-oil upgrading is needed in

India. The upgraded pyrolysis oil products may be modeled as

C8 and C10 hydrocarbons.

83

85

An overall description of the biomass fast pyrolysis process to

produce naphtha and diesel is shown in Figure. To produce

hydrogen employ optional equipment. Biomass with 25%

moisture content is dried to 7% moisture and ground to 3-mm-

diameter size prior to being fed into a fluid bed pyrolyzer

operating at 480°C and atmospheric pressure. Standard

cyclones remove solids consisting mostly of char particles

entrained in the vapors exiting the pyrolyzer. Vapors are

condensed in indirect contact heat exchangers, yielding liquid

bio-oil that can be safely stored at ambient conditions prior to

upgrading to transportation fuels.

86

Non-condensable gases are recycled to the pyrolysis reactor

after being combusted to provide process heat. Also,

pyrolysis solid products may be sent to a combustor to

provide heat for the drying and pyrolysis process. Excess

solid char is a low-heating-value coal substitute. Bio-oil

upgrading generates a fuel compatible with existing

infrastructure. Ash content can cause fouling and plugging of

high-temperature equipment. Minerals catalyze thermal

decomposition reactions that are detrimental to the

production of quality pyrolysis oil. Biomass washing using

water or acid-removal techniques can reduce alkali content

in biomass.

87

Hydrotreating and hydrocracking (catalytic processing with hydrogen)

are commonly employed in the petroleum industry to remove undesired

compounds such as sulfur from crude oil and to break large

hydrocarbon molecules to produce clean naphtha and diesel.

Bio-oil typically contains significant quantities of oxygenated

compounds that are undesirable for combustion in vehicle engines.

Hydrotreating can convert oxygen found in bio-oil to water and carbon

dioxide molecules, leaving hydrocarbons that are suitable for internal

combustion engines.

Complex hydrocarbon compounds are found in bio-oil, and

hydrocracking is a potential method to decompose these heavy

compounds into naphtha and diesel.

Biomass gasification

89

Updraft Gasifier • Here, the biomass

moves down from the top of the gasifier while the gases released being light move up, resulting in a counter-current. The quality of producer gas obtained from the up-draft gasifier is fair since it has impurities like tar.

90

However, this resultant producer

gas has a higher capacity to

generate heat on burning (due to

the impurities) and can be used

well for heat generation

activities.

Downdraft Gasifier

• Biomass moves down from the top of the gasifier and the resultant gas also moves downward—a co-current process. The gas quality is good though it generates less heat on burning. The gas released from such gasifiers is used mainly for electricity generation.

91

How can biomass supplement coal as a feedstock for power

plants?

For decentralised small / medium scale power plants

Biomass Power Programmes are available

100

Biomass energy is not necessarily the ‘poor man’s

fuel’, its role is rapidly changing for a combination of

environmental, energy, climatic, social and

economic reasons. It is increasingly becoming the

fuel of the environmentally-conscious, rich society.

The use of biomass energy has many pros and

cons. One of the major barriers confronting

renewable energy is that the conventional fuels do

not take into account the external costs of energy,

such as environmental costs.

101

It is important to create a new situation in which all

sources of energy are put on a more ‘equal footing’.

For biomass energy, which has little or no

environmental costs, the internalisation of the cost

of energy could be a major determinant for its large-

scale implementation. This, together with

agricultural productivity and technological advances,

could be a key determinant in ensuring greater

competitiveness with fossil fuels.

103

The Biomass Power Programme of India has reached the take off

stage, after dedicated and sustained efforts over the last decade.

The total potential is about 19,500 MW, including 3,500 MW of

exportable surplus power from bagasse-based co-generation in

sugar mills, and 16,000 MW of grid quality power from other

biomass resources.

106

The Program could CONSISTS OF the following Components:

· Interest Subsidy for Bagasse/Biomass Co-generation projects,

including IPP mode projects;

· Interest Subsidy for Biomass Power Projects, including captive power

projects;

· Grants to MW-scale projects with 100% producer gas engines, and

Advanced Biomass Gasification projects;

· Promotion of Industrial Co-generation projects in core industry sector

for surplus power generation;

· Promotional Incentives for awareness creation, training and

preparation of Detailed Project Reports; and

· Grants for Biomass Resource Assessment Studies.

109

BIOMASS INTEGRATED GASIFIER /GAS TURBINE (BIG/ GT) TECHNOLOGY

• HIGH THERMODYNAMIC CYCLE EFFICIENCY

GAS TURBINES TECHNOLOGY IS MADE AVAILABLE NOW AT REASONABLE COSTS

LOW UNIT CAPITAL COST AT MODEST SCALES FEASIBLE

IT IS EXPECTED THAT THIS TECHNOLOGY WILL BE COMMERCIALLY SUCCESSFUL IN THE NEXT TEN YEARS.

112

Briquetting: Briquetting

improves the energy density of

loose biomass, which is either

charred and compacted or

directly compacted in the form

of briquettes.

Biomass briquettes made

through manual processes can

be used as cooking fuel in

homes. Briquettes produced

through mechanical processes

can be used in boilers and

furnaces.

113

Fuel derived from compacting the biomass into

dense block is known as Briquette. It is cheaper

and requires no other raw material and produce

heat equivalent to other fuel. Now a days

biomass briquetting is used by the same

industries where the low-density biomass is

produced. Jute waste, groundnut shell, coffee

husk, coir pith and rice husk is used for

Briquetting.

What is Biomass Briquetting?

114

Biomass briquettes in Malawi.

• The briquette evaluation was made in terms of physical and chemical characteristics (like material content, size, weight, energy content), costs for the fuel and usability in household cooking stoves. The feasibility of the production method for each briquette type was also evaluated.

• The briquettes were compared with the characteristics of firewood and charcoal.

115

Agro-residues and agro-industry residues-1

• Agricultural or agro-industrial biomass is

generally difficult to handle because of its

bulky and scattered nature, low thermal

efficiency and copious liberation of smoke

during burning. It will be useful to compress

them into manageable and compact pieces,

which have a high thermal value per unit

weight.

116

Agro-residues and agro-industry residues-2

• Biomass residues and by products are

available in abundance at the agro processing

centres (rice husk, bagasse, molasses,

coconut shell, groundnut shell, maize cobs,

potato waste, coffee waste, whey), farms

(rice straw, cotton sticks, jute sticks).

117

briquetting or pelleting

• The process is called

biomass briquetting or pelleting.

• Compressed biomass briquettes are usually cylindrical in shape with a diameter between 30 to 90 mm and length varying between 100 to 400mm.

• Briquetting consists of applying pressure to a mass of particles with or without a binder and converting it into compact aggregate. Ram type and screw type machinery are used for the manufacture of briquettes.

118

Briquetting technology

• Ram type consists of a plunger or rod which forces the material received from a hopper into a die, which is not usually heated by external means.

• The screw type machine employs a screw auger which forces the material into a pipe heated by electricity.

• The choice of the type of machinery depends on many factors.

119

Ram type [piston type] briquetting machine

• Ram type consists of a

plunger or rod which

forces the material

received from a hopper

into a die, which is not

usually heated by

external means.

120

Ram type briquetting press

• Common in India, alternate to screw type.

• Material is compressed in horizontal press, made into a cylindrical continuous log; Cut to pellets later.

• Log diameter is 50 mm for a 500 kg per hour machine and 90 mm for a 1500 kg / hr machine

121

Screw type briquetting machine

• The screw type machine

employs a screw auger

which forces the

material into a pipe

heated by electricity.

122

Screw type briquetting Press

• The material is extruded under compression continuously in the form of a log, under screw.

• These logs are partially carbonized and free of volatile compounds.

• They can supplement charcoal / lignite as solid fuel for small scale uses.

• Wear of screw is a problem and designers of machine have solved this.

124

PELLETISING

• Biomass material is compressed

through many holes by giving very high

pressure from rollers to the material.

125

Preparing biomass for pellet making

126

PELLETISING: High pressure, smaller size

• In pelletising, the biomass material

is compressed through many holes by giving very

high pressure from rollers to the material.

• The stick is continuous but the size of pellet is

smaller (6-25 mm in diameter) than briquettes.

• Pelletizing is more efficient and recognized as a

good method because of low investment.

127

• Pelletizing, though introduced very recently, is

considered to be most wanted method due to its

high bulk density.

• Ring and Flat Die are two types found in this

category.

• The Ring die method is mostly used for making

animal feed, which has high bulk density.

• The flat die is used for low bulk density.

PELLETISING: Ring and Flat Die

130

Combustion: A chemical process _ Oxidation of reduced forms of carbon

and hydrogen by free radical processes. Chemical properties of the bio-

fuels determine the higher heating value of the fuel and the pathways of

combustion.

136

Table: 1.

Chemical composition of some biomass material

Species Total ash% Lignin% Hemi-

cellulose%

Cellulose %

Bagasse 2.2 18.4 28.0 33.1

Rice Straw 16.1 11.9 24.1 30.2

Wheat Straw

6.0 16.0 28.1 39.7

140

To determine the quantity of air required for complete combustion

• To determine the air, the ultimate analysis is useful.

• C + O2 = CO2 +97644 cal /mole [[15 o C]

• H2 +O2 = H2O + 69000 cal / mole [15 o C]

• Excess air % = (40*MCg)/(1- MCg) where MCg is moisture

content on total wt basis (green). For typical biomass fuels at

50 % moisture content, for grate firing system about 40%

excess air may be required.

• For suspension fired and fluidized bed combustion, air

required may be 100 % excess

• Distribution of air and whether it is pre-heated is also

important

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Higher Heating Value

• Calorific value of a fuel is the total heat produced when a unit mass of a fuel is completely burnt with pure oxygen. It is also called heating value of the fuel. When the c.v. is determined, water formed is considered as in vapour state, net c. v. is got.

• Gross calorific value or higher heating value of a fuel containing C, H and O is given by the expression:

• Cg =[C x 8137 + (H--O/8) x 34500]/100 where C, H and O are in % and Cg is in calories.

• Net calorific value is the difference between GCV and latent heat of condensation of water vapor present in the products

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Fluidized Bed Combustion

• The remainder of the heat is available for direct

transmission to heat transfer surfaces immersed within the

bed; in boiler applications these comprise a set of steam

raising tubes.

• The heat transfer to immersed surfaces is uniformly high in

comparison with the variation of radiation heat transfer

through a conventional combustion chamber.

• Less heat transfer surface is required for a given output

and a boiler system occupies a smaller volume.

Liquid Fuels from Biomass

Ethanol & Biodiesel

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Liquid and gaseous transport fuels derived from a range of

biomass sources are technically feasible. They include

• methanol,

• ethanol,

• dimethyl esters,

• pyrolytic oil,

• Fischer- Tropsch gasoline and distillate and

• Biodiesel from (i) Jatropha , Pongamia pinnata, Salvadora

persica, Madhuca longifolia and

• ( ii) hydrocarbon from Euphorbia species.

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Sugar cane, like other plants, absorbs carbon dioxide from the

atmosphere during photosynthesis. Burning ethanol made from

sugar thus returns to the atmosphere what was recently there, rather

than adding carbon that was previously underground. Unfortunately,

turning sugar cane into ethanol uses more energy, and thus causes

more greenhouse-gas emission, than making petrol from crude oil.

Nevertheless, says Lew Fulton of the International Energy Agency, a

sister body of the OECD, studies suggest that Brazil's present

method of making ethanol fuel from sugar leads to net savings of

about 50% in greenhouse-gas emissions per kilometre travelled,

compared with running cars on petrol.

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• Photosynthetic organisms include plants, algae and some

photosynthetic bacteria.

• Photosynthesis is the key to making solar energy available

in useable forms for all organic life in our environment.

• These organisms use energy from the sun to combine

water with carbon dioxide (CO2) to create biomass.

• While other Biofuels Programs can focus on terrestrial

plants as sources of fuels,

• Microalgae Program can be concerned with photosynthetic

organisms that grew in aquatic environments.

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Microalgae are, as the name suggests, microscopic

photosynthetic organisms. Like macroalgae, these organisms

are found in both marine and freshwater environments.

Microalgae generally produce more of the right kinds of

natural oils needed for biodiesel.

Biologists have categorized microalgae in a variety of classes,

mainly distinguished by their pigmentation, life cycle and basic

cellular structure. The four most important (at least in terms of

abundance) are: The diatoms (Bacillariophyceae), The green

algae (Chlorophyceae), The blue-green algae

(Cyanophyceae) and The golden algae (Chrysophyceae).

Algae-for-fuel

• Among algal fuels' attractive characteristics:

• they do not affect fresh water resources,

• can be produced using ocean / wastewater,

• are biodegradable

• relatively harmless to the environment if spilled.

• As of 2008, such fuels remain too expensive, with the cost of

various algae species typically between US$5–10 per kg dry

weight.

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165

Algae cost more per pound yet can yield over 30

times more energy per acre than other, second-

generation biofuel crops.

It is claimed that algae can produce more oil in

an area the size of a two-car garage than an

football field of soybeans, because almost the

entire algal organism can use sunlight to

produce lipids, or oil.

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• Studies show that algae can produce up to 60% of their

biomass in the form of oil.

• Because the cells grow in aqueous suspension where

they have more efficient access to water, CO2 and

dissolved nutrients, microalgae are capable of producing

large amounts of biomass and usable oil.

• Either high rate algal ponds or photo-bioreactors may be

used for the growing of the algae.. This oil can then be

turned into biodiesel used in automobiles. Regional

production of microalgae and processing into biofuels will

provide economic benefits to rural communities.

Name a recently published Reference book and point out the bioenergy related chapters in it.

See the next three slides

172

Reference book Chapters 12 to15

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The Energy and Resources Institute

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The promotion of energy using biomass available

in form of natural waste such as agricultural

residue, sugarcane bagasse, banana stems,

organic effluents, cattle dung, night soil, fuelwood

and twigs holds considerable promise. A National

Programme on Biomass Power/Cogeneration was

launched to optimise the use of a variety of

forestry-based and agro-based residues for power

generation by the adoption of state-of-the-art

conversion technologies.

Reference book from T. E. R. I.

Chapters 12 to15

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SOME MORE BOOKS ON BIOENERGY

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generate power from-biomass

Engineering

energy consumption

energy route

role of biomass

biomass utilization

biomass residue

manual animal energy

low energy efficiency

power sources