PRESENTED BY :PRESENTED BY :

SAURABH UMRAOSAURABH UMRAO B.TECH 3’rd YEAR B.TECH 3’rd YEAR

(CHEMICAL ENGINEERING) (CHEMICAL ENGINEERING)

MNNIT ALLAHABADMNNIT ALLAHABAD

Method of Producing Syngas from Gasification of Bagasse

NEED OF SYN-GASNEED OF SYN-GAS As the amount of fossil fuels available decreases and the As the amount of fossil fuels available decreases and the

cost of petroleum-based fuels increases, there is a greater cost of petroleum-based fuels increases, there is a greater need for alternative fuel sources.need for alternative fuel sources.

One promising process for biofuel production involves One promising process for biofuel production involves the formation of synthesis gas which can then be the formation of synthesis gas which can then be converted to useful compounds.converted to useful compounds.

Syngas is formed by a variety of processes with sources Syngas is formed by a variety of processes with sources ranging from commonly-used fossil fuels to completely ranging from commonly-used fossil fuels to completely renewable organic compounds.renewable organic compounds.

But the more efficient source for the production of But the more efficient source for the production of syngas is bagasse as it is cheap & easily available.syngas is bagasse as it is cheap & easily available.

The main components of syngas are carbon monoxide, The main components of syngas are carbon monoxide, carbon dioxide, and hydrogen. Each of these components carbon dioxide, and hydrogen. Each of these components can be converted to valuable products.can be converted to valuable products.

Syngas is the direct end-product of the gasification Syngas is the direct end-product of the gasification process. process.

The energy density of Syngas is only about 50 percent The energy density of Syngas is only about 50 percent that of natural gas and is therefore mostly suited for use that of natural gas and is therefore mostly suited for use in producing transportation fuels and other chemical in producing transportation fuels and other chemical products. products.

USES OF SYN-GASUSES OF SYN-GAS

Synthesis gas is can also be used as an intermediary Synthesis gas is can also be used as an intermediary building block for the final production (synthesis) of building block for the final production (synthesis) of various fuels such as synthetic natural gas, methanol and various fuels such as synthetic natural gas, methanol and synthetic petroleum fuel. synthetic petroleum fuel.

In a purified state, the hydrogen component of Syngas In a purified state, the hydrogen component of Syngas can also be used to directly power hydrogen fuel cells for can also be used to directly power hydrogen fuel cells for electricity generation.electricity generation.

Production of syngas with a high heating value or Production of syngas with a high heating value or high CO + Hhigh CO + H22 content to be used as a fuel for content to be used as a fuel for cogeneration in sugar industries.cogeneration in sugar industries.

Using free fall reactor & packed bed reactor for Using free fall reactor & packed bed reactor for almost complete conversion of bagasse to syngas with almost complete conversion of bagasse to syngas with a little ash content.a little ash content.

OBJECTIVEOBJECTIVE

India is second largest producer of sugar in world India is second largest producer of sugar in world hence producing a huge amount of bagasse around hence producing a huge amount of bagasse around 1.2 giga tone as a waste.1.2 giga tone as a waste.

Low economic state of sugar industry in India due to Low economic state of sugar industry in India due to high consumption of power .high consumption of power .

Syngas is a ultimate fuel which can be used in I.C. Syngas is a ultimate fuel which can be used in I.C. Engines.Engines.

CAUSE ANALYSISCAUSE ANALYSIS

ElementElement Sugarcane leavesSugarcane leaves

(% w/w;dry) (% w/w;dry)

BagasseBagasse

(% w/w;dry)(% w/w;dry)

Fixed carbon Fixed carbon 14.914.9 20.120.1

VolatileVolatile 77.477.4 75.875.8

Ash contentAsh content 7.77.7 4.24.2

Higher heating Higher heating value, MJ /kgvalue, MJ /kg

17.4317.43 18.1118.11

PROXIMATE ANALYSIS

CONTENTS OF BAGASSE

ElementElement Sugarcane leavesSugarcane leaves

(% w/w; dry) (% w/w; dry)

BagasseBagasse

(% w/w; dry)(% w/w; dry)

Carbon Carbon 39.839.8 44.144.1

HydrogenHydrogen 5.5 5.5 5.265.26

Oxygen Oxygen 46.8 46.8 44.444.4

NitrogenNitrogen 0.190.19 --

ULTIMATE ANALYSIS

The rapid pyrolysis of the bagasse is conducted in the The rapid pyrolysis of the bagasse is conducted in the free-fall reactor .free-fall reactor .

The char from the rapid pyrolysis is further pyrolyzed The char from the rapid pyrolysis is further pyrolyzed in nitrogen atmosphere in a thermo-balance with a in nitrogen atmosphere in a thermo-balance with a slow heating rate (20°C/mm) up to 850°C .slow heating rate (20°C/mm) up to 850°C .

Gasification of char particles is done in packed bed Gasification of char particles is done in packed bed reactor for the generation of syngas.reactor for the generation of syngas.

PROPOSED IDEA

Now syngas can be used in furnace for heating in sugar Now syngas can be used in furnace for heating in sugar industries as well as to counter the need of power in these industries as well as to counter the need of power in these industries and even for other purposes.industries and even for other purposes.

Syngas produced can also be used for I.C. Engines.Syngas produced can also be used for I.C. Engines.

PYROLYSIS OF BAGASSEPYROLYSIS OF BAGASSE

The rapid pyrolysis of the bagasse is conducted in the The rapid pyrolysis of the bagasse is conducted in the free-fall reactor .free-fall reactor .

The bagasse samples are placed on a circular stainless The bagasse samples are placed on a circular stainless steel net plate (sample holder).steel net plate (sample holder).

Nitrogen gas at atmosphere pressure passes downwards Nitrogen gas at atmosphere pressure passes downwards the column from the plate in which the biomass sample the column from the plate in which the biomass sample is placed.is placed.

MECHANISM INVOLVED

FREE FALL REACTOR

NN22 gas is passed to assure oxygen-free environment gas is passed to assure oxygen-free environment and to evacuate the produced gas during the treatment.and to evacuate the produced gas during the treatment.

Nitrogen flow of 2L/min is used in the pyrolysis.Nitrogen flow of 2L/min is used in the pyrolysis.

The gases produced during the thermo-chemical The gases produced during the thermo-chemical treatment are evacuated from the net plate downwards treatment are evacuated from the net plate downwards and cooled before exiting it.and cooled before exiting it.

The char produced are evacuated from the net plate The char produced are evacuated from the net plate downwards and collected in the char hopper.downwards and collected in the char hopper.

The residence time of the particles in the free fall reactor The residence time of the particles in the free fall reactor is not enough for the final pyrolysis.is not enough for the final pyrolysis.

The char obtained by rapid pyrolysis contains a fraction The char obtained by rapid pyrolysis contains a fraction that can be further volatilized by slow pyrolysis.that can be further volatilized by slow pyrolysis.

So the char from the rapid pyrolysis is further pyrolyzed So the char from the rapid pyrolysis is further pyrolyzed in nitrogen atmosphere in a thermo-balance with a slow in nitrogen atmosphere in a thermo-balance with a slow heating rate (20°C/mm) up to 850°C for the final heating rate (20°C/mm) up to 850°C for the final conversion up to 57%.conversion up to 57%.

COMPARISON BETWEEN SLOW AND COMPARISON BETWEEN SLOW AND RAPID PYROLYSISRAPID PYROLYSIS

Slow PyrolysisSlow Pyrolysis

Char yield (wt % maf)Char yield (wt % maf) 1010

Reactivity in gasificationReactivity in gasification

(wt. % loss/min)(wt. % loss/min)

.7.7

Rapid PyrolysisRapid Pyrolysis

Char yield (wt % maf)Char yield (wt % maf) 2.42.4

Reactivity in gasificationReactivity in gasification

(wt. % loss/min )(wt. % loss/min )

3.43.4

PRODUCTS OF PYROLYSISPRODUCTS OF PYROLYSIS

Gaseous productGaseous product COCO22, H, H22, CO, CH, CO, CH44, C, C22HH22, C, C22HH44, C, C22HH66,Benzene etc,Benzene etc..

Liquid productsLiquid products Tar, High Molecular Weight Hydrocarbons, WaterTar, High Molecular Weight Hydrocarbons, Water..

Solid productsSolid products CharChar..

EFFECT OF TEMERATURE ON THE EFFECT OF TEMERATURE ON THE PYROLYSISPYROLYSIS

The temperature markedly influences the heating rate.The temperature markedly influences the heating rate.

The heat flux is proportional to the driving force & The heat flux is proportional to the driving force & the temperature difference between the particle and the temperature difference between the particle and the environment.the environment.

At higher temperature , the heat flux and the heating At higher temperature , the heat flux and the heating rate are higher. The higher heating rate results in rate are higher. The higher heating rate results in decrease char yield.decrease char yield.

Higher temperatures favor cracking of the hydrocarbons Higher temperatures favor cracking of the hydrocarbons in the gaseous products and thus increase the yield of in the gaseous products and thus increase the yield of hydrogen.hydrogen.

Higher temperature has also decreased the content of Higher temperature has also decreased the content of COCO22 in the gases and increased the content of CO . in the gases and increased the content of CO .

The char yield decreases when temperature is increased The char yield decreases when temperature is increased from 800°C to 1000°C.from 800°C to 1000°C.

INFLUENCE OF PARTICLE SIZE ININFLUENCE OF PARTICLE SIZE IN

THE PYROLYSISTHE PYROLYSIS

The size of the particles affects the heating rate.The size of the particles affects the heating rate.

The heat flux and the heating rate are higher in small The heat flux and the heating rate are higher in small particles than in large particles.particles than in large particles.

The higher heating rate decreases the char yield.The higher heating rate decreases the char yield.

Smaller particle size has affected also the composition Smaller particle size has affected also the composition of the gas. of the gas.

Smaller particle has favored the cracking of Smaller particle has favored the cracking of hydrocarbons with increases of hydrogen yield.hydrocarbons with increases of hydrogen yield.

In smaller particle the produced gas leaves the particle In smaller particle the produced gas leaves the particle faster than the large particles.faster than the large particles.

Particle Size,mmParticle Size,mm 0.5-0.86 0.5-0.86 0.86-1.0 0.86-1.0

Temperature, Deg. cent.Temperature, Deg. cent. 800 900 1000 800 900 1000 800 900 1000 800 900 1000

Gas yield , wt % mafGas yield , wt % maf 81.5 83.8 87.5 81.5 83.8 87.5 79.1 81.2 87.0 79.1 81.2 87.0

Tar yield, wt % mafTar yield, wt % maf 0.5 0.5 0.3 0.5 0.5 0.3 0.4 0.3 0.2 0.4 0.3 0.2

Char yield, wt % mafChar yield, wt % maf 5.0 4.7 4.1 5.0 4.7 4.1 6.6 5.5 4.7 6.6 5.5 4.7

Final slow pyrolysisFinal slow pyrolysis

Char yield after total Char yield after total pyrolysis, wt % maf pyrolysis, wt % maf

2.6 3.3 2.6 2.6 3.3 2.6 2.8 2.4 2.3 2.8 2.4 2.3

Char removed by slow Char removed by slow pyrolysis, wt % maf pyrolysis, wt % maf

49 30 37 49 30 37 57 56 5157 56 51

Reactivity,wt loss% minReactivity,wt loss% min 1.8 1.5 1.8 1.8 1.5 1.8 3.1 3.4 3.0 3.1 3.4 3.0

EFFECT OF TEMPERATURE ON THE YIELD OF PRODUCTS OBTAINED BY RAPID PYROYSIS OF

BAGASSE IN A FREE FALL REACTOR

GASIFICATION OF CHAR PARTICLES IN GASIFICATION OF CHAR PARTICLES IN

PACKED BEDSPACKED BEDS

Packed bed reactor configuration results in a high Packed bed reactor configuration results in a high conversion of pyrolysis intermediates and hence a conversion of pyrolysis intermediates and hence a relatively clean gas can be obtained. relatively clean gas can be obtained.

It is a high temperature process in which a solid It is a high temperature process in which a solid fuel is reacted with steam, carbon dioxide, air or fuel is reacted with steam, carbon dioxide, air or hydrogen under very low oxygen giving a mixture hydrogen under very low oxygen giving a mixture of gases including hydrogen and carbon monoxide.of gases including hydrogen and carbon monoxide.

Gasification reaction is :Gasification reaction is : C + 1/2OC + 1/2O22 CO + Heat CO + Heat C + HC + H22O(Steam) CO + HO(Steam) CO + H22 –Heat –Heat

EXPERIMENTAL SET-UP FOR THE PACKED BED REACTOR

MECHANISMMECHANISM

In the packed bed reactor the flame front moves In the packed bed reactor the flame front moves upwards, towards the top from where air is being upwards, towards the top from where air is being drawn and, eventually the front reaches the top. drawn and, eventually the front reaches the top.

Experiments are stopped when the flame front reaches Experiments are stopped when the flame front reaches the top. the top.

The system is run at fixed flow rates and the upward The system is run at fixed flow rates and the upward rate of propagation of the flame front is measured.rate of propagation of the flame front is measured.

The exit gas composition is determined using on-line The exit gas composition is determined using on-line analyzer for hydrogen, carbon monoxide, carbon analyzer for hydrogen, carbon monoxide, carbon dioxide and oxygen. dioxide and oxygen.

TEMPERATURE PROFILE AT DIFFERENT LOCATIONS

(FROM BOTTOM OF THE REACTOR) IN A PACKED BED AT A FLUX OF 0.06 KG/m2.S

TEMPERATURE PROFILE PREDICTION ALONG THE LENGTH OF THE REACTOR

AT A FLUX OF 0.1 KG/m2.S

Now the temperature profile is further used to obtain Now the temperature profile is further used to obtain the propagation front movement, i.e. velocity.the propagation front movement, i.e. velocity.

It is observed that the glowing zone is approximately It is observed that the glowing zone is approximately 25-35 mm deep (3-4 particle depth) and the peak 25-35 mm deep (3-4 particle depth) and the peak temperature measured in the bed is in the range of temperature measured in the bed is in the range of 1000-1230 K depending upon the mass flux. 1000-1230 K depending upon the mass flux.

At low mass flux, i.e. below about 0.05 kg/m2.s, the gas At low mass flux, i.e. below about 0.05 kg/m2.s, the gas is not combustible and the CO level is very low is not combustible and the CO level is very low

(1 per cent). (1 per cent).

In most of the cases, measured hydrogen in the gas is In most of the cases, measured hydrogen in the gas is about 2.0-4.5 per cent.about 2.0-4.5 per cent.

Finally from the blower we get a mixture of CO and Finally from the blower we get a mixture of CO and HH22 (i.e. Syngas) which is filtered out and cool it by (i.e. Syngas) which is filtered out and cool it by using cooler to maintain its temperature till 40 °C. using cooler to maintain its temperature till 40 °C.

Then cool gas is send to engine from where Then cool gas is send to engine from where electricity is generated.electricity is generated.

Bagasse have high moisture content around 11 % Bagasse have high moisture content around 11 %

so it is need to be dried before feeding in free fall so it is need to be dried before feeding in free fall reactor.reactor.

It has low calorific value in comparison to coal gas.It has low calorific value in comparison to coal gas.

LIMITATIONS

Bagasse gasification is more efficient than direct Bagasse gasification is more efficient than direct combustion .combustion .

However in spite of its potential ,the use of bagasse However in spite of its potential ,the use of bagasse as a source of energy is not so common.as a source of energy is not so common.

A liter of liquid fuel can be saved with 4-5 kg. Of A liter of liquid fuel can be saved with 4-5 kg. Of biomass.biomass.

CONCLUSION

A Programme on Biomass Based Power Plants at Taluka Level. A Programme on Biomass Based Power Plants at Taluka Level. Report of the Task Force constituted by Ministry of Non-Report of the Task Force constituted by Ministry of Non-conventional Energy Sources, Government of India, New Delhi, conventional Energy Sources, Government of India, New Delhi, (March 1995).(March 1995).

Jain, Bio-Resource Gasification Sharing of Experiences; Book of Jain, Bio-Resource Gasification Sharing of Experiences; Book of Abstracts – BioResource 94 –Biomass Resources : a means to Abstracts – BioResource 94 –Biomass Resources : a means to sustainable development, Bangalore, India 13 (October 1994).sustainable development, Bangalore, India 13 (October 1994).

H. S. Mukunda, S. Dasappa, P. J. Patel, N. K. S. Rajan and U. H. S. Mukunda, S. Dasappa, P. J. Patel, N. K. S. Rajan and U. Shrinivasa, Gasifiers and Combustors for biomass technology and Shrinivasa, Gasifiers and Combustors for biomass technology and field studies, Energy for Sustainable Development, field studies, Energy for Sustainable Development, 1( 3)1( 3), 27-38 , 27-38 (1994).(1994).

Ph. Hasler and R. Buhler, Gasification of urban waste wood Ph. Hasler and R. Buhler, Gasification of urban waste wood (allholtz); Report submitted to the International Energy Agency, (allholtz); Report submitted to the International Energy Agency, Biomass Gasification Working Group, 1-35 (September 1994).Biomass Gasification Working Group, 1-35 (September 1994).

REFERENCES

Design and Development of 10-15 kW Gasifier Running on Design and Development of 10-15 kW Gasifier Running on Loose Sugarcane Leaves. Final Project Report submitted to Loose Sugarcane Leaves. Final Project Report submitted to Ministry of Non-conventional Energy Sources (MNES), Ministry of Non-conventional Energy Sources (MNES), Government of India, New Delhi by Nimbkar Agricultural Government of India, New Delhi by Nimbkar Agricultural Research Institute (NARI), Phaltan, (May 1992).Research Institute (NARI), Phaltan, (May 1992).

R. M. Jorapur, A. K. Rajvanshi, Development of a Sugarcane R. M. Jorapur, A. K. Rajvanshi, Development of a Sugarcane Leaf Gasifier for Electricity Generation, Biomass and Leaf Gasifier for Electricity Generation, Biomass and Bioenergy, Bioenergy, 88, 91-98 (1995)., 91-98 (1995).

A.K. Rajvanshi, M. S. Joshi, Development and operational A.K. Rajvanshi, M. S. Joshi, Development and operational experience with topless wood gasifier running a 3.75 kW diesel experience with topless wood gasifier running a 3.75 kW diesel engine pumpset, Biomass engine pumpset, Biomass 1919, 47-56 (1989)., 47-56 (1989).

Use of Low Density Biomass Gasification System for Process Use of Low Density Biomass Gasification System for Process Heat Applications in Metallurgical and Agro-based Industry; Heat Applications in Metallurgical and Agro-based Industry; Final Project Report submitted to The Rockefeller Foundation, Final Project Report submitted to The Rockefeller Foundation, New York by Nimbkar Agricultural Research Institute (NARI), New York by Nimbkar Agricultural Research Institute (NARI), Phaltan, (January 1996). Phaltan, (January 1996).

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