By

Dr. Virendra K. Vijay

Centre for Rural Development & TechnologyIndian Institute of Technology, Delhi

Hauz Khas, New Delhi, IndiaE-mail: vkvijay@rdat.iitd.ernet.in,

vkvijay14@hotmail.com

IITD

Biogas enrichment and bottling technology

for automobile fuel-IIT Delhi Technology -

Case study of goshala in Rajasthan

Introduction

Biogas is an important renewable energy resource for rural areas in India.

It is produced by anaerobic digestion of biological wastes.

It is an environment friendly, clean, cheap and versatile fuel.

Biogas generally comprise of 55-65 % methane, 35-45 % carbon dioxide,0.5-1.0 % hydrogen sulfide and traces of water vapour.

Average calorific value of biogas is 20 MJ/m3 (4713 kcal/m3).

Biogas like Liquefied Petroleum Gas (LPG) cannot be liquefied undernormal temperature and pressure.

Critical temperature required for liquefaction of methane is -82.1oC at 4.71MPa pressure, therefore use of biogas is limited nearby thebiogas plant.

An estimate indicates that India has a potential of generating 6.38 X 1010

m3 of biogas from 980 million tones of cattle dung produced annually.

The heat value of this gas amounts to 1.3 X 1012 MJ. In addition, 350million tones of manure would also produce along with biogas.

Organic Wastes & their Estimated Availability in India

Sr.

No.

Organic Wastes Estimated Quantity

1. Municipal Solid waste 30 million tons/year

2. Municipal liquid waste 12000 million litres/day

3. Distillery (243 units) 8057 kilolitres/day

4. Press mud 9 million tons/year

5. Food & fruit processing wastes 4.5 million tons/year

6. Willow dust 30000 tons/year

7. Dairy industry waste 50-60 million litres/day

8. Paper & pulp industry waste (300 mills) 1600 m3/day

9. Tannery (2000 units) 52500 m3 waste water/day

Source: MNES Report, Renewable Energy in India and business opportunities,

MNES. Govt. of India, New Delhi, 2001

Biogas Production Potential from different Wastes

Utilization of Biogas

Cooking: Biogas can be used in a specially designed burner for cooking

purpose. A biogas plant of 2 cubic metres capacity is sufficient for

providing cooking fuel needs of a family of about five persons.

Lighting: Biogas is used in silk mantle lamps for lighting purpose. The

requirement of gas for powering a 100 candle lamp (60 W) is 0.13 cubic

metre per hour.

Power Generation: Biogas can be used to operate a dual fuel engine to

replace up to 80 % of diesel-oil. Diesel engines have been modified to run

100 per cent on biogas. Petrol and CNG engines can also be modified

easily to use biogas.

Transport Fuel: After removal of CO2, H2S and water vapour, biogas can

be converted to natural gas quality for use in vehicles.

Biogas Technology Status

India has been pioneering country in developing simple and easy to operate

biogas plants.More than 4 million family type biogas plants have installed so

far.

The government of India has been running National Biogas and Manure

Management Program (NBMMP) for the welfare of the weaker section of the

society.

100% Biogas engines are in operation in the country.

95% methane to make it suitable to be used as a transport fuel and for

blending with natural gas where the gas grid is available.

From small to large size , large no. of biogas systems are in place across the

country - 1cum/day to more than 20,000 cum/day

and there exists large potential in this area

New Initiative by MNRE

BGFP Program: Demonstration of an Integrated Technology

Package on Biogas-Fertilizer Plants (BGFP) for Generation,

Purification/ Enrichment, Bottling and Piped distribution of

Biogas towards harnessing ‘Near Total Potential of suitable

Biomass in Rural Areas in India.

The Ministry of New and Renewable Energy support of 50% can be

made available for taking up such technology projects. Balance 50% of the

cost of the project is required to be invested/ mobilized by the

entrepreneur/ developer. However, at least 20% of the cost of the project

is to be met by the entrepreneur/user agency in case loan is availed from

banks/ financial institutions including NABARD and IREDA.

The capacity of BGFP could be 200, 400, 500, 1000 m3 biogas/ day and

multiples there of depending on the availability of suitable biomass feed-

materials and cattle-dung.

Need for the Biogas Refining and Bottling

Potential of biogas is not fully utilized and commercialized so far.

For commercialization, its area of application may widen; from cookingfuel to vehicle fuel/or transportable fuel

For use as a vehicle fuel, it should be bottled like CNG.

Before bottling, it should enriched in methane content from 55 % to 95%; similar to CNG.

Refining and Compression of Biogas

Purification is carried out to enrich biogas by scrubbing off the unwantedcomponents i.e. carbon dioxide (CO2) and hydrogen sulfide (H2S).

It is essential to have more energy per unit volume of compressed biogasand to get rid of the corrosive effect of H2S.

Various purification processes include absorption into water, absorptionby chemical, pressure swing adsorption and membrane separation.

One of the simple and cheap method is the use of pressurized water as anabsorbent liquid.

Design of Water Scrubbing System

Water scrubbing method is found suitable for biogas

enrichment in rural areas.

Water is good solvent for CO2.

The solubility of CO2 in water is governed by variation in

pressures and temperatures.

Approximate solubility of CO2 in water

Pressure

(atmo-spheric)

Solubility, kg of CO2 per kg of water at different temperatures.

0 ˚C 10 ˚C 20 ˚C 30 ˚C

1 0.40 0.25 0.15 0.10

20 3.15 2.15 1.30 0.90

50 7.70 6.95 6.00 4.80

Biogas Enrichment and Bottling System

11

Fig.1: Experimental setup for biogas purification and bottling

5

1

3

2

4

6 7

1-Biogas plant

2-Ball valve

3-Water remover

4-Receiver mounted compressor

5-Pressure gauge

6-Gas Storage Vessel

7-Rotameter

8-Supporting stand

9-Reshching rings

10-Scrubber

11-Safety valve

12-Water sprayer

13-Flange

14-View glass

15-Water outlet

16-Water pump

17-Gas filter

18-Pressure reducer

19-Three stage gas compressor

20-CNG Cylinder10

9

12

8

15

16

19

18

13

17

14

NOT TO SCALE

20

Success Case Study of Biogas as Automotive Fuel

Rajasthan Go Sewa Sangh, Durgapura,

Rajasthan: ( 50 years old NGO established for upliftment

of rural poor bycow and cow products)

More than 30 acre campus in Jaipur consisted of :

•goshala - 250 cows, 3 biogas plants

•naturopathy & ayurvedic indoor hospital,

•milk processing and medicine making units,

•products retail out let,

•biogas slurry drying and vermi -compost making

unit,

•agricultultural farm for organic vegetable & fodder

cultivation,

•Biogas Plants: 3 biogas plants

85 cum +60 cum+30 cum = 175 cum/day

•Biogas enrichment and power generation

started in July 2006

•Biogas bottling Plant started in Dec 2007

since then it has been running successfully.

A three wheeler runs on biogas daily about 100

km. and approximate 4 kg Bio-CNG is required .( Demonstration support from DST, Govt of India)

Produce locally and consume locally

for sustainability of resources on mother

earth - Mahatma Gandhi

Decentralised production and utilisation of

energy is the only solution for energy security

in rural areas

BIOGAS UTILIZATION

1.Automobile Fuel:

Three wheeler luggage carrier –runs 100-110 km/day on enriched

biogas

Till now run more than 12500 km on biomethane

2. Power Generation

100% Biogas Genset : 12 kW - 5 hrs/ day

Water pumping

Lighting in the complex

3. Thermal Application :

gas consumption for cooking in their naturopathy hospital kitchen and

Ayurvedic medicine preparations

3 Biogas Plants at Goseva Sangh

Jaipur

Biogas slurry dried and vermicomposted –filled in bags

KVIC/Jan0828

Comparison of Gaseous Emissions for Heavy Vehicles (Bus)

in g/km

CO Hydro Carbons NOX CO2 Particles

Diesel 0.2 0.4 9.73 1053 0.1

Natural gas 0.4 0.6 1.1 524 0.022

Biogas 0.08 0.35 5.44 223 0.015

Source: A report on biogas technology and biogas use in Sweden, Traffic and Public

Transport Authority, City of Gothenburg, November 2000.

Emission Benefits of Biogas

Possible entrepreneurial avenues which can have PoA- CDM benefits in Rural Areas with Biogas

Large Scale/ Community level Biogas Enterprises for

1. Cooking needs- Pipeline supply

2. Electricity Production and Supply

3. Rural sanitation & bio manure production

4. Cylindering of methane available from biogas plantfor tractors and rural vehicles and production ofbio manure

Large Scale/ Community level Biogas Enterprises forCooking needs- Pipeline supply and Rural Sanitation andbio manure production

I. Size of Biogas Plant- 85 m3/day No. of families Beneficiaries—50

Cow dung required—2 Tons/day- 250/Ton

A complex of 20 community toilets

Gas utilization—Cooking

If for Cooking – 2 hrs. morning & 2 hrs. evening(1.5 m3/familyper day)

Pipeline length—up to 1km. distance

Pipe quality—HDPE, pressurize system—0.3 kg./cm2(Rs. 2.5 lacscost)

Gas charge—150/month-family

II. Raw material—Cow dung+ Toilet (community-20 toilets costs 1.5lacs)

III. Slurry Management—Biogas digested slurry

Four options-

1. Liquid slurry

2. Recycle water (upto 40 to 50% only)

3. Dry slurry

4. Semi dry

•Local consumption of slurry is advised

•Quality of slurry should be maintained

Cost estimates

Non- recurring cost—Rs. 8,20,000 ($ 20,500)

Recurring/ Variable cost—Rs. 2,12,000 ($ 5300)

Manpower-- Rs.96,000 ($ 2400)

Depreciation—Rs.80,000 ($ 2000)

Sum of recurring cost- 3,88,000 ($ 9700)

Revenue generation- 5,90,000-3,88,000=Rs.2,02,000 (& 5050)

Note- In addition to this Carbon credit benefit to thetune of Rs.71,000/yr. ($ 1775) will also be available.

Large Scale/ Community level Biogas Enterprises for Electricity

Generation and supply for domestic consumption, water supply and

community consumption and Rural sanitation

15 KVA Power Generating System from - 85 m3/day Biogas Plant

No. of families Beneficiaries—50

No. of Animals—200

Cow dung required—2 Tons/day- 250/Ton

Gas utilization— Electricity

Domestic connection—2CFL, 1 Fan= 100 Wt.*50=5000Wt.

Water supply connection—4000 Wt.

Community Hall—2 CFL, 2 Fan & 1 TV.= 500 Wt.

Cost estimates

A. Non recurring

Sum =8,50,000 ($ 21,250)

B. Recurring

Sum=3,87,000 ($ 9675)

Income—

Electricity supply 130 unit @ Rs.6 per unit *365 = Rs.2,84,700/yr. ($7117)

Slurry—Rs.1500/day= Rs.5,00,000/yr. ($ 12,500)

CDM benefits – Rs.71,000/yr. ($ 1775)

Sum= Rs.7,84,000 ($ 19,600)

Surplus—

Rs. 7,84,000-3,87,000= Rs. 3,97,000 ($ 9925)

Cylindering of methane available from biogas plant

for tractors and rural vehicles and production of bio

manure

Biogas plant of 300 M3 per day capacity with enrichment and bottling

CAPITAL COST – Rs. 28,00,000.00 ($ 70,000)

OPERATION COST –

A. Fixed operational cost-3,00,000 per annum ($ 7500)

B. Annual Running (Operational) Cost: -12,00,000 per annum

Total cost of Operation = Rs. 15,00,000 /- ($ 37,500)

Income:-

income generate by selling CBG and slurry = Rs. 22,00,000/- ($ 55,000)

Profit = Rs. 7,00,000/- ($ 17,500)

Payback Period = 4 years

Advantages of this biogas

programme under PoA-CDM

Reduction of methane & CO2emission from cattle dung

Replacement of diesel/petrol by enriched Biogas in

vehicles/ pump sets

Replacement of LPG/ biomass/ kerosene from biogas for

cooking needs

Electricity

Issues: Monitoring

Verification

Conclusions

India has second largest biogas programme in the world at ruraland as well as urban levels.

Technologies/models have been successfully developed forbiogas enrichment and bottling for automobile applications inIndia

There is need to develop a sustainable renewable energyprogramme on biogas for replacing petroleum products byutilization of biogas in the country as commercial enterprises.

This will help in green energy technology and reducing greenhouse gases emissions.There is good scope of taking it underPoA- CDM activity.