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SYNGAS production

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Presented & published the paper in a national level chemical engineering conference “ACHEME 2009”.

SYNGAS production

  1. 1. PRESENTED BY : SAURABH UMRAO B.TECH 3’rd YEAR (CHEMICAL ENGINEERING) MNNIT ALLAHABAD Method of Producing Syngas from Gasification of Bagasse
  2. 2. NEED OF SYN-GAS <ul><li>As the amount of fossil fuels available decreases and the cost of petroleum-based fuels increases, there is a greater need for alternative fuel sources. </li></ul><ul><li>One promising process for biofuel production involves the formation of synthesis gas which can then be converted to useful compounds. </li></ul>
  3. 3. <ul><li>Syngas is formed by a variety of processes with sources ranging from commonly-used fossil fuels to completely renewable organic compounds. </li></ul><ul><li>But the more efficient source for the production of syngas is bagasse as it is cheap & easily available. </li></ul><ul><li>The main components of syngas are carbon monoxide, carbon dioxide, and hydrogen. Each of these components can be converted to valuable products. </li></ul>
  4. 4. <ul><li>Syngas is the direct end-product of the gasification process. </li></ul><ul><li>The energy density of Syngas is only about 50 percent that of natural gas and is therefore mostly suited for use in producing transportation fuels and other chemical products. </li></ul>USES OF SYN-GAS
  5. 5. <ul><li>Synthesis gas is can also be used as an intermediary building block for the final production (synthesis) of various fuels such as synthetic natural gas, methanol and synthetic petroleum fuel. </li></ul><ul><li>In a purified state, the hydrogen component of Syngas can also be used to directly power hydrogen fuel cells for electricity generation. </li></ul>
  6. 6. <ul><ul><li>Production of syngas with a high heating value or high CO + H 2 content to be used as a fuel for cogeneration in sugar industries. </li></ul></ul><ul><ul><li>Using free fall reactor & packed bed reactor for almost complete conversion of bagasse to syngas with a little ash content. </li></ul></ul>OBJECTIVE
  7. 7. <ul><li>India is second largest producer of sugar in world hence producing a huge amount of bagasse around 1.2 giga tone as a waste. </li></ul><ul><li>Low economic state of sugar industry in India due to high consumption of power . </li></ul><ul><li>Syngas is a ultimate fuel which can be used in I.C. Engines. </li></ul>CAUSE ANALYSIS
  8. 8. PROXIMATE ANALYSIS CONTENTS OF BAGASSE Element Sugarcane leaves (% w/w;dry) Bagasse (% w/w;dry) Fixed carbon 14.9 20.1 Volatile 77.4 75.8 Ash content 7.7 4.2 Higher heating value, MJ /kg 17.43 18.11
  9. 9. ULTIMATE ANALYSIS Element Sugarcane leaves (% w/w; dry) Bagasse (% w/w; dry) Carbon 39.8 44.1 Hydrogen 5.5 5.26 Oxygen 46.8 44.4 Nitrogen 0.19 -
  10. 10. <ul><li>The rapid pyrolysis of the bagasse is conducted in the free-fall reactor . </li></ul><ul><li>The char from the rapid pyrolysis is further pyrolyzed in nitrogen atmosphere in a thermo-balance with a slow heating rate (20°C/mm) up to 850°C . </li></ul><ul><li>Gasification of char particles is done in packed bed reactor for the generation of syngas. </li></ul>PROPOSED IDEA
  11. 11. <ul><li>Now syngas can be used in furnace for heating in sugar industries as well as to counter the need of power in these industries and even for other purposes. </li></ul><ul><li>Syngas produced can also be used for I.C. Engines. </li></ul>
  12. 12. <ul><ul><li>PYROLYSIS OF BAGASSE </li></ul></ul><ul><ul><li>The rapid pyrolysis of the bagasse is conducted in the free-fall reactor . </li></ul></ul><ul><ul><li>The bagasse samples are placed on a circular stainless steel net plate (sample holder). </li></ul></ul><ul><ul><li>Nitrogen gas at atmosphere pressure passes downwards the column from the plate in which the biomass sample is placed. </li></ul></ul>MECHANISM INVOLVED
  13. 13. FREE FALL REACTOR
  14. 14. <ul><ul><li>N 2 gas is passed to assure oxygen-free environment and to evacuate the produced gas during the treatment. </li></ul></ul><ul><ul><li>Nitrogen flow of 2L/min is used in the pyrolysis. </li></ul></ul><ul><ul><li>The gases produced during the thermo-chemical treatment are evacuated from the net plate downwards and cooled before exiting it. </li></ul></ul><ul><ul><li>The char produced are evacuated from the net plate downwards and collected in the char hopper. </li></ul></ul>
  15. 15. <ul><li>The residence time of the particles in the free fall reactor is not enough for the final pyrolysis. </li></ul><ul><li>The char obtained by rapid pyrolysis contains a fraction that can be further volatilized by slow pyrolysis. </li></ul><ul><li>So the char from the rapid pyrolysis is further pyrolyzed in nitrogen atmosphere in a thermo-balance with a slow heating rate (20°C/mm) up to 850°C for the final conversion up to 57%. </li></ul>
  16. 16. COMPARISON BETWEEN SLOW AND RAPID PYROLYSIS Slow Pyrolysis Char yield (wt % maf) 10 Reactivity in gasification (wt. % loss/min) .7 Rapid Pyrolysis Char yield (wt % maf) 2.4 Reactivity in gasification (wt. % loss/min ) 3.4
  17. 17. PRODUCTS OF PYROLYSIS <ul><li>Gaseous product </li></ul><ul><li>CO 2 , H 2 , CO, CH 4 , C 2 H 2 , C 2 H 4 , C 2 H 6 ,Benzene etc . </li></ul><ul><li>Liquid products </li></ul><ul><li>Tar, High Molecular Weight Hydrocarbons, Water . </li></ul><ul><li>Solid products </li></ul><ul><li>Char . </li></ul>
  18. 18. EFFECT OF TEMERATURE ON THE PYROLYSIS <ul><li>The temperature markedly influences the heating rate. </li></ul><ul><li>The heat flux is proportional to the driving force & the temperature difference between the particle and the environment. </li></ul><ul><li>At higher temperature , the heat flux and the heating rate are higher. The higher heating rate results in decrease char yield. </li></ul>
  19. 19. <ul><li>Higher temperatures favor cracking of the hydrocarbons in the gaseous products and thus increase the yield of hydrogen. </li></ul><ul><li>Higher temperature has also decreased the content of CO 2 in the gases and increased the content of CO . </li></ul><ul><li>The char yield decreases when temperature is increased from 800°C to 1000°C. </li></ul>
  20. 20. INFLUENCE OF PARTICLE SIZE IN THE PYROLYSIS <ul><li>The size of the particles affects the heating rate. </li></ul><ul><li>The heat flux and the heating rate are higher in small particles than in large particles. </li></ul><ul><li>The higher heating rate decreases the char yield. </li></ul>
  21. 21. <ul><li>Smaller particle size has affected also the composition of the gas. </li></ul><ul><li>Smaller particle has favored the cracking of hydrocarbons with increases of hydrogen yield. </li></ul><ul><li>In smaller particle the produced gas leaves the particle faster than the large particles. </li></ul>
  22. 22. EFFECT OF TEMPERATURE ON THE YIELD OF PRODUCTS OBTAINED BY RAPID PYROYSIS OF BAGASSE IN A FREE FALL REACTOR Particle Size,mm 0.5-0.86 0.86-1.0 Temperature, Deg. cent. 800 900 1000 800 900 1000 Gas yield , wt % maf 81.5 83.8 87.5 79.1 81.2 87.0 Tar yield, wt % maf 0.5 0.5 0.3 0.4 0.3 0.2 Char yield, wt % maf 5.0 4.7 4.1 6.6 5.5 4.7 Final slow pyrolysis Char yield after total pyrolysis, wt % maf 2.6 3.3 2.6 2.8 2.4 2.3 Char removed by slow pyrolysis, wt % maf 49 30 37 57 56 51 Reactivity,wt loss% min 1.8 1.5 1.8 3.1 3.4 3.0
  23. 23. GASIFICATION OF CHAR PARTICLES IN PACKED BEDS <ul><ul><li>Packed bed reactor configuration results in a high conversion of pyrolysis intermediates and hence a relatively clean gas can be obtained. </li></ul></ul><ul><ul><li>It is a high temperature process in which a solid fuel is reacted with steam, carbon dioxide, air or hydrogen under very low oxygen giving a mixture of gases including hydrogen and carbon monoxide. </li></ul></ul><ul><ul><li>Gasification reaction is : </li></ul></ul><ul><ul><li>C + 1/2O 2 CO + Heat </li></ul></ul><ul><ul><li>C + H 2 O(Steam) CO + H 2 –Heat </li></ul></ul>
  24. 24. EXPERIMENTAL SET-UP FOR THE PACKED BED REACTOR
  25. 25. MECHANISM <ul><li>In the packed bed reactor the flame front moves upwards, towards the top from where air is being drawn and, eventually the front reaches the top. </li></ul><ul><li>Experiments are stopped when the flame front reaches the top. </li></ul><ul><li>The system is run at fixed flow rates and the upward rate of propagation of the flame front is measured. </li></ul><ul><li>The exit gas composition is determined using on-line analyzer for hydrogen, carbon monoxide, carbon dioxide and oxygen. </li></ul>
  26. 26. TEMPERATURE PROFILE AT DIFFERENT LOCATIONS (FROM BOTTOM OF THE REACTOR) IN A PACKED BED AT A FLUX OF 0.06 KG/m2.S
  27. 27. TEMPERATURE PROFILE PREDICTION ALONG THE LENGTH OF THE REACTOR AT A FLUX OF 0.1 KG/m2.S
  28. 28. <ul><li>Now the temperature profile is further used to obtain the propagation front movement, i.e. velocity. </li></ul><ul><li>It is observed that the glowing zone is approximately 25-35 mm deep (3-4 particle depth) and the peak temperature measured in the bed is in the range of 1000-1230 K depending upon the mass flux. </li></ul><ul><li>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 </li></ul><ul><li>(1 per cent). </li></ul>
  29. 29. <ul><li>In most of the cases, measured hydrogen in the gas is about 2.0-4.5 per cent. </li></ul><ul><li>Finally from the blower we get a mixture of CO and H 2 (i.e. Syngas) which is filtered out and cool it by using cooler to maintain its temperature till 40 °C. </li></ul><ul><li>Then cool gas is send to engine from where electricity is generated. </li></ul>
  30. 30. <ul><li>Bagasse have high moisture content around 11 % </li></ul><ul><li>so it is need to be dried before feeding in free fall reactor. </li></ul><ul><li>It has low calorific value in comparison to coal gas. </li></ul>LIMITATIONS
  31. 31. <ul><li>Bagasse gasification is more efficient than direct combustion . </li></ul><ul><li>However in spite of its potential ,the use of bagasse as a source of energy is not so common. </li></ul><ul><li>A liter of liquid fuel can be saved with 4-5 kg. Of biomass. </li></ul>CONCLUSION
  32. 32. <ul><li>A Programme on Biomass Based Power Plants at Taluka Level. Report of the Task Force constituted by Ministry of Non-conventional Energy Sources, Government of India, New Delhi, (March 1995). </li></ul><ul><li>Jain, Bio-Resource Gasification Sharing of Experiences; Book of Abstracts – BioResource 94 –Biomass Resources : a means to sustainable development, Bangalore, India 13 (October 1994). </li></ul><ul><li>H. S. Mukunda, S. Dasappa, P. J. Patel, N. K. S. Rajan and U. Shrinivasa, Gasifiers and Combustors for biomass technology and field studies, Energy for Sustainable Development, 1( 3) , 27-38 (1994). </li></ul><ul><li>Ph. Hasler and R. Buhler, Gasification of urban waste wood (allholtz); Report submitted to the International Energy Agency, Biomass Gasification Working Group, 1-35 (September 1994). </li></ul>REFERENCES
  33. 33. <ul><li>Design and Development of 10-15 kW Gasifier Running on Loose Sugarcane Leaves. Final Project Report submitted to Ministry of Non-conventional Energy Sources (MNES), Government of India, New Delhi by Nimbkar Agricultural Research Institute (NARI), Phaltan, (May 1992). </li></ul><ul><li>R. M. Jorapur, A. K. Rajvanshi, Development of a Sugarcane Leaf Gasifier for Electricity Generation, Biomass and Bioenergy, 8 , 91-98 (1995). </li></ul><ul><li>A.K. Rajvanshi, M. S. Joshi, Development and operational experience with topless wood gasifier running a 3.75 kW diesel engine pumpset, Biomass 19 , 47-56 (1989). </li></ul><ul><li>Use of Low Density Biomass Gasification System for Process Heat Applications in Metallurgical and Agro-based Industry; Final Project Report submitted to The Rockefeller Foundation, New York by Nimbkar Agricultural Research Institute (NARI), Phaltan, (January 1996). </li></ul>
  34. 34. THANK YOU

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