Long term operation of a small biogasdiesel dual fuel engine for on farm electricity generation

Seminar Topic-Long–term operation of a small biogas/diesel dual-fuel engine for on-farm electricity generation

Presented by:Ravikant Sainath GhotekarM.Tech 1st year, FMP, AGFE, IIT Kharagpur.(13AG61R16) 1

Author-N. Tippayawong, Promwungkwa & P. Rerkkriangkrai.Department of Mechanical Engineering, Chiang Mai University, Thailand

Introduction Objectives Material & Methods Results & Discussion Conclusions References

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Content:

1. Energy requirement: Energy is the ‘prime mover’ for the development of any

country

Day by day its demand is increasing because of economic development, rapid growth of population and change in living standard

Out of 6,38,596 villages of India 1,12,574 villages are still un-electrified. Indu R. Pillai & Rangan Banerjee (2009)

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Introduction: Need of research

2. Problems associated with the use of fossil fuels: Exhaustible thus highly stressed

Increase in cost day by day making it unsuitable for use in rural areas

Responsible for environmental pollution

Thus it is important to identify alternative sources of energy which can replace fossil fuel partially or completely

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Need of research continued….

3. Scope of use of biogas: Animal dung is the primary source of biogas production. Total

livestock population in India is 529.7 million out of which bovine population is 304.4 million (highest in the world). (National dairy development board report 2012)

India produces over 83 MT of dry dung cake which is used annually by rural households as domestic fuel for cooking. (Dikshit and Birthal, 2010)

960 million tonnes of solid waste is generated every year out of which 600 MT of wastes from agricultural sources alone. (Asokan et al. 2007)

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Need of research continued….

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Need of research continued…. Economically feasible and environmental friendly

Biogas generated by cattle dung available in the country would be equivalent to nearly 195 billion kW-h of energy annually or equivalent to 24 billion liters of kerosene. (Venkatraman, 1991)

In addition of this 236 billion tones of manure with a nitrogen content of 3.5 million tones can also be produced. (Venkatraman, 1991)

1. To minimize the amount of diesel used and maximize its replacement by biogas while maintaining acceptable engine operation

2. To evaluate the effect of long-term operation on performance and wear of the dual-fuel engine

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Objectives:

A biogas is produced from anaerobic biodegradation of organic material in the absence of oxygen and in the presence of anaerobic micro-organisms

In this work, biogas from swine manure was used

It was stored and compressed to approximately 245 Pa in a closed, collapsible rubber dome from where it was fed to an engine intake port at a pressure of about 100–150 Pa

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Materials & Methods:1) FUELS: A) Primary Fuel- Biogas

The feed pipelines were fitted with a condensation trap and a gas treatment unit i.e. H2S & CO2 removal to filter moisture and react with trace of sulphur compounds present in the biogas prior to entering the engine

The biogas was regularly collected and analysed for its properties and composition. Major gaseous constituents were analysed by gas chromatography

B) Secondary Fuel- DieselComparison of biogas and diesel

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Material & Methods contd…

Engine Specification: (Mitsubishi DI-800 model) Rated power- 5.5 kw at 2400 rpm, Single Cylinder Four stroke CI, Cubic Capacity: 411cc, Bore- 82mm, Stroke- 78 mm, Compression ratio- 8:1, Maximum torque developed- 25 Nm at 1900 rpm. Diesel engine is modified to use biogas & diesel as a

fuel in it i.e. dual-fuel mode

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2) ENGINE SETUP:


Engine is Connected to 5 kw, 220 v single phase AC 50 Hz Alternator acting as a dynamometer to allow for accurate manual speed and load control.(Test set-up)

The electrical loading is obtained through a load bank consisting of light bulbs.

Biogas was supplied through a plastic pipe and mixed inlet air in a ventury type mixer upstream of inlet manifold.

Diesel consumption was measured by timing a fixed amount of diesel used in a calibrated burette.

Engine speed was measured by digital tachometer. Data logger was used to measure and store all readings.

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Material & Methods contd…3) PROCEDURE:

The air and biogas flow rates were regulated using a Dwyer mass flow meter and a biogas meter, respectively

Type K thermocouples connected to a data logger were installed to measure inlet air and exhaust temperatures, the cylinder wall as well as coolant temperatures.

Initially, the engine was conditioned by running at idle for 24 h on diesel fuel. Subsequently, the test procedure began with normal operation at idle for about 15 min. The engine speed was then increased gradually to 1400 rpm.

Once stability was attained, a constant speed testing was carried out with a load applied.

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Material & Methods contd…3) PROCEDURE continued….

The test were conducted at a number of constant speeds from 1400 to 2000 rpm under both diesel and dual mode.

Under biogas/diesel dual-fuel operation, an effort has been made to keep the pilot amount of diesel fuel constant, while the engine power output was adjusted through the amount of biogas.

For long term operation engine was set to run on dual mode at constant speed of 1500 rpm to generate electricity continuously.

The voltage and frequency of generation were monitored and the unit automatically shut down if there were deviation outside set limits

The engine was set to run all day and night, accumulating about 200h durability test in about 10 days.

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Engine check and services were performed twice at first 200 and second at 500 hour.

All critical components were taken apart, weighed, inspected and photographically recorded.

The engine was later cleaned and reassembled in strict accordance with all furnished specifications.

Oil change were carried out after 500 h at an interval of 200-250 h according to the engine manufacturer.

A detailed record of attention and maintenance required was kept throughout the durability test.

Test was carried out for 2000 h and then engine components were dissembled weighed, inspected visually and given rating for wear.

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Percentage of diesel replaced by biogas

Where is diesel consumption rate in normal

diesel operation. (kg/s)

is diesel consumption rate in dual- fuel operation. (kg/s)

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Total specific fuel consumption and thermal efficiency (ɳ)

W: Engine power output (kW),H: Fuel heating value (kJ/kg)


Biogas/diesel dual-fuel was found to give acceptable operation & power output up to 1800 rpm, with biogas substitution or diesel replacement rate over 90% by mass.

The total specific fuel consumption was not found to fluctuate significantly with engine speed. They were, on average, about 550 and 450 g/kWh for dual-fuel and normal diesel operations, respectively.

Dual-fuel operation have higher thermal efficiency than that under normal diesel operation. Maximum thermal efficiency was found approximately 23% at 1500 rpm for electricity generation.

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1) Short term engine performanceResults:

At the end of the endurance test, the engine was taken apart and subjected to final inspection. Only a thin layer of hard carbon deposit was observed.

Engine component wear as mass loss over 2000h operation was calculated & it was found that connecting rod bush that had the highest mass loss of 20.9%, but other components have percentage mass loss generally in the range of 0.5 – 4.3%.

Lubricating oil did not appear to thicken and its colour was not observed to differ from its unused state.

Long term engine durability tests for 2000h showed no problems of unusual wear.

The power output was attained to the initial level after maintenance and appeared to stabilize throughout the remaining test period.

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2) Long term engine performanceResults contd….

From analysis of the experimental results, it was demonstrated that over 90% substitution rate by biogas can be achieved.

Dual-fuel operation had slightly higher power output than normal diesel operation by about 7% on average.

With respect to energy conversion, dual fuel operation showed superior efficiency compared to normal diesel operation within the range of engine speeds considered.

As far as the engine durability test is concerned, the use of biogas/diesel dual-fuel operation up to the first 2000h did not appear to affect the engine performance and wear adversely.

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Conclusions:

The engine experienced no significant change in power output and energy efficiency. Unusual wear on critical components was not detected.

There was a small degree of carbon deposits building up inside the combustion chamber, periodic maintenance and service can solve this problem.

Biogas/diesel dual-fuel engine operation is a promising technique for on-farm electricity generation. Significant amount of diesel can be replaced by biogas. Successful long-term operation was demonstrated without any major drawback.

Adoption of this technology can boost the farms’ renewable energy usage and reduce diesel fuel cost.

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Conclusions contd….

The model biogas plant that uses wet waste to generate biogas/electricity on the University of Agricultural Sciences-Bangalore campus has been functioning well from nearly a year.

The plant generates 90 kg of cooking gas/day that is used to generate around 320 units of power/day.

This takes care of 25% of the university’s electricity requirement.

The raw material for power generation comprises cow dung from around 175 cattle at the university apart from leftovers at the students’ hostels. The plant requires 4.5 to 5 tonnes of organic waste a day for its operation.

The total cost of the 20-kW plant is about Rs. 40 lakh.

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A model biogas plant in Bangalore that produces 320 units of power a daySource: http://www.thehindu.com dated: September 10, 2012

Example indicating potential of Biogas

Tippayawong, N., Promwungkwa, A., Rerkkriangkrai P.,(2007). Long-term operation of a small biogas/diesel dual-fuel engine for on-farm electricity generation. Biosystems Engineering 98 ( 2007 ) 26 – 32.

Pillai, R., Banerjee R.,(2009).Renewable Energy in India:Status and potential. Energy, 34, 970-980.

Venkataraman, P.(1991).Biogas programes in India.TIDE, Tata energy research institute, New Delhi, 1, 1-18.

Asokan, P., Saxena, M., Shagam, R., (2007). Solid waste generation in India. Building and environment, 42, 2311-2320.

Dikshit A. K., Birthal S. P. Environmental value of dung in mixed crop-livestock systems. Indian journal of animal sciences, 80(7) : 679-684, July 2010.

Stefan M., Biogas fuel for internal combustion engines. Annals of faculty of engineering hunedoara. University of Novisad, montenegro 2004.

http://www.nddb.org http://www.greenetik.eu/en/solutions/biogas-production

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References:

http://www.nddb.org/

24http://www.greenetik.eu/en/solutions/biogas-production

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BIOGAS FORMATION

Final Methanogenesis Reaction:CO2 + 4 H2 → CH4 + 2H2OCH3COOH → CH4 + CO2

Component %Methane 65.6Carbon dioxide 26.4Nitrogen 6.0Oxygen 2.0H2S Traces

Biogas Composition

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Biogas yields from different biomass

Some facts about potential of Biogas

Temperature needed:The two most widely used types of microorganisms are mesophiles, which undergo mesophilic digestion, and thermophiles, which undergo thermophilic digestion.• Mesophilic : 25-40°C • Thermophilic: 45-80°C

Retention time :• Cattle manure - 12 – 18 days• Pig manure - 10 – 15 days

pH requirement:• The microorganisms that are responsible for the creation of

methane require an environment between the pH ranges of 6.5-8.0

Water : Dung proportion- 2:127


A 4m3 digester produces 1m3 of gas/day, enough for daily cooking and heating. Source: SURUDE (Foundation for Sustainable Rural Development) NGO, Tanzania

It takes from 2 to 8 weeks to digest a load of waste, depending on the temperature.

The average calorific value of biogas is about 21-23.5 MJ/m³, so that 1 m³ of biogas corresponds to 0.5-0.6 Litre diesel fuel or about 6 kWh. Source: FNR, Agency for Renewable Resources, Germany, 2009.

According to www.spaceproject.com1. 1m³ of biogas can give as much light as a 60-100 Watt bulb for 6 hours2. 1m³ of biogas can cook 3 meals for a family of 5 - 63. 1m³ of biogas can replace 0.7 kg of petrol4. 1m³ of biogas can generate 1.25 kW hours of electricity

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According to Ministry of new & renewable energy (MNRE )2011…


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Source: http://www.vivamgroup.co.in/small_biogas.html


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Modifications required in diesel engine to use biogas


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Engine test set-up


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Material & Methods contd…Biogas –inlet air mixing

device

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GAS CHROMATOGRAPHY


Source: www.wikipedia.com

Stationary phase: Microscopic layer of liquid Mobile Phase: carrier inert gases

Why…? Biogas To be used as fuel for internal combustion engines,

it has been recommended a CH4 concentration greater than 90% (Harasimowicz et al, 2007).

However CO2 has a typical concentration of ~ 40%. This high CO2 concentration reduces the engine power output proportionally to its concentration, limiting the use of biogas in electrical power plants driven by internal combustion engines.

The high content of H2S (~3500 ppm) causes corrosion in the metallic parts at the interior of the engine.

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H2S & CO2 Removal


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Amine based H2S and CO2 biogas scrubberJ.I. Huertas, N. Giraldo and S. Izquierdo, Automotive Engineering Research Center, Mexico


H2S removing efficiency: 98% to 95% CO2 removing efficiency: 87% to 50%

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Comparison between short-term engine power outputfrom diesel (o) and dual-fuel (□) operations, and fraction of biogas replacement (∆) in dual-fuel operation.

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Comparison between short-term engine fuel economy and thermal efficiency from diesel (o, ●) and dual-fuel (□, )))) operations

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Engine component wear shown as mass loss over 2000h of operation

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Comparison between engine components before and after the 2000h endurance test

(a) cylinder head

(b) piston

(C) Exhaust valve

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Variation of average electrical power generated with operation time

Long term operation of a small biogasdiesel dual fuel engine for on farm electricity generation

Technology

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