Production of Gaseous Fuels Pongamia Residue P M V Subbarao Professor Mechanical Engineering Department Indian Institute of Technology Delhi, New Delhi Enhance the value of Fuel Energy ….

Pongamia Residue De-oiled cake – Rich Proteins Shells – Rich Cellulose

The Mind of Inventor Robert Boyle 17th-century natural philosopher, chemist, physicist, and inventor, also noted for his writings in theology. Scientific interest in the manufacturing of gas produced by the natural decomposition of organic matter, was first reported in the seventeenth century by Robert Boyle

Major Biological Events in Anaerobic Digestion hydrolytic bacteria

Fitness De-oiled Cakes for Hydrolysis Dry Pongamia Seed Cake Dry Jatropha Seed Cake Seed Cakes soaked in water

Ultimate Methane Potential of A Feed Material C a H b O c N d + X H 2 O  Y CH 4 + Z CO 2 + d NH 3 X = (4a – b + 2c + 3d)/4 Y = (4a + b – 2c – 3d)/8 Z = (4a – b + 2c + 3d)/8 Buswells equation Number of moles per mole of ’organic matter’

8 Ultimate Methane Potential B ult = 22.4 Nl/mol * (4a + b – 2c – 3d) mol 1000 l/m 3 8 * (12a + b + 16c + 14d)g [Nm 3 /g] B ult = * (1/2a + 1/8b – 1/4c – 3/8d) (12a + b + 16c + 14d) [Nm 3 /ton] [Nm 3 ] = one cubic meter of gas at standard state: 1 atm and 0 o C

Proximate analysis of feed materials (As Received Basis) Feed material Moisture content % Oil content % Total solids % Volatile solids % Non- volatile solids % Cattle dung 81.6Nil Jatropha oil seed cake Pongamia oil seed cake

Ultimate Analysis and carbon-nitrogen ratio : VM of feed materials Sr. No. Feed materialC (%)H (%)N (%)C/N ratio 1 Cattle Dung Jatropha oil seed cake Pongamia oil seed cake

1.Entire VS in feed material cannot be degraded. 2.The degradable material can only be completely converted to gas if a longer Hydraulic Retention Time (HRT) is used. 3.Part of the input material is inorganic (even though it may contain H). 4.The digestion process may not be optimal (inhibition). Practical Methane Production

The Inoculum Living element(s) of the parasite are able to contaminate a host feed material. It is the "primary inoculum" that enters the host and induces the degradation. The "secondary inoculum", resulting from the fructification of part of the contaminated host population, causes the spread in the host population

Preparation of Substrates and Determination of Their Properties  Mixing of de-oiled cake with Inoculum.  Dilution ratio and solids concentration.  To keep TS in between % and to maintain flow ability of substrates.  More surface for Bacterial hydrolysis.  An inoculation ratio of 1:10 used in laboratory experimentation.  With and with out cow dung.  A dilution ratio of 3:1 and 4:1 for jatropha cake  and, 3:1 and 3.5:1 for pongamia cake.

Preliminary Batch Biomethanation Study Experimental setup for batch biomethanation study Range of ambient temperature variation 24.5 to 35.1 °C Range of substrate temperature variation 24 to 34.5 °C Period of Experimental Study:15 th March 2006 to 12 th June 2006

Composition of prepared substrates and their C/N ratio, TS, VS and their dilution ratio [as received (live dilution ratio) and absolute dilution ratio (dry basis)] Sl. No. Treatment designation Substrate constituents Dilution ratio, Water : Cake C/N ratio Substrate concentration Cake, g Water, ml Dung, g Inoculum, g LiveAbsolute% TS% VS 11.0 DR [CD] :111.6: Jatropha Oil Cake Substrates 23.0 DR [5JC:0CD] :13.4: DR [5JC:1CD] :13.5: DR [5JC:2CD] :13.5: DR [5JC:3CD] :13.6: DR [5JC:4CD] :13.6: DR [5JC:5CD] :13.7: DR [5JC:0CD] :14.5: DR [5JC:1CD] :14.5: DR [5JC:2CD] :14.5: DR [5JC:3CD] :14.6: DR [5JC:4CD] :14.6: DR [5JC:5CD] :14.6:

16 Sl. No. Treatment designation Substrate constituents Dilution ratio, water : cake C/N ratio Substrate concentration Cake, g Water, ml Dung, g Inoculum, g LiveAbsolute% TS% VS Pongamia Oil Cake Substrates DR [5PC:0CD] :13.7: DR [5PC:1CD] :13.7: DR [5PC:2CD] :13.8: DR [5PC:3CD] :13.9: DR [5PC:4CD] :13.9: DR [5PC:5CD] :13.9: DR [5PC:0CD] :14.3: DR [5PC:1CD] :14.3: DR [5PC:2CD] :14.3: DR [5PC:3CD] :14.4: DR [5PC:4CD] :14.4: DR [5PC:5CD] :14.4: Continued… 16

17 Experimental Setup used for Preliminary Batch Study 17

Conclusions from Characterization of Feed Materials and Preliminary Batch Biomethanation Study  Low yield and very poor quality of biogas was observed during the preliminary batch biomethanation study.  A major challenge in biomethanation of these deoiled cakes is lacking of inherent bacteria like cattle dung.  Lack of these inherent bacteria demands a special attention for operation of digester with cake.  Other major deficiency of cake is the presence of long chain free fatty acids, which are prone to destroy the population of bacteria.  Thus the microbes present in cattle dung inoculum could not survive in new environment.  There may be a continuous drop in population of bacteria in the inoculum.

Need for Development of New Inoculums  The microbes present in cattle dung inoculums could not survive in deoiled cake-water environment.  The substrates of jatropha and pongamia oil cakes might have created a sudden and drastic change in environment for the bacterial activity resulting in their inhibition.  There was a continuous drop in population of bacteria in the inoculums.  This is due to effect of bacterial inhibition since the substrates were new for the bacteria present in the cattle dung inoculum.  This proves that production of effective (special) inoculum in a small aspirator bottles with little amount of initial inoculum (taken from a cattle dung digester) is not feasible.

Biogas plant (20 m 3 /d) capacity available at IIT Delhi 20

Development of Special Inoculum 20 m 3 /d BGPAbout 12 m 3 CD inoculum Feeding of pongamia oil cake in 3:1 DR for 15 days No feeding of CD before last 3 months Schedule I 2 kg pongamia oil cake with 6 kg water for 5 days Start of gas production Continued 5 kg pongamia oil cake with 15 kg water for 10 days Schedule II Drop in gas yield Increase in gas yield Constant gas yield (10-15 day) at 30 cm height 10 cm height 21 Biogas Plant before Feeding Started

Biogas Plant After Feeding of Oil Cake Slurry

Evolution of Microbes  This shows the adaptation of bacteria to the environment offered by new substrates possibly by developing into a suitable strain.  This acclimatization is due to fact that,  when the concentrations of inhibitory or toxic materials were slowly increased within the environment,  many microorganisms could rearrange their metabolic resources, thus overcoming the metabolic blockage produced by the normally inhibitory or toxic material.  However, sufficient time should be made available for this rearrangement to take place where there is drastic change in environment (feed material).  The slurry of the biogas plant stabilized with pongamia oil seed cake was used as inoculum for further studies.