Production of Gaseous Fuels Pongamia Residue
P M V SubbaraoProfessor
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
CaHbOcNd + X H2O Y CH4 + Z CO2 + d NH3
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
Bult = 22.4 Nl/mol * (4a + b – 2c – 3d) mol
1000 l/m3 8 * (12a + b + 16c + 14d)g
[Nm3/g]
Bult = 22400 * (1/2a + 1/8b – 1/4c – 3/8d)
(12a + b + 16c + 14d)
[Nm3/ton]
[Nm3] = one cubic meter of gas at standard state: 1 atm and 0 oC
Proximate analysis of feed materials(As Received Basis)
Feed material
Moisture content
%
Oil content
%
Total solids
%
Volatile solids %
Non-volatile solids %
Cattle dung 81.6 Nil 18.4 14.4 4.0
Jatropha oil seed cake
7.5 8.3 92.5 86.4 07.0
Pongamia oil seed cake
10.5 7.2 89.5 85.3 05.2
Ultimate Analysis and carbon-nitrogen ratio : VM of feed materials
Sr. No.
Feed material C (%) H (%) N (%) C/N ratio
1 Cattle Dung 35.20 4.60 1.55 22.7
2 Jatropha oil seed cake
48.80 6.20 3.85 12.7
3 Pongamia oil seed cake
47.80 6.50 5.50 8.7
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 18-22 % 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
5 L Aspirator Bottle[DIGESTER]
5 L Aspirator BottleFilled With Water
Gas Contituents Analysis(Biogas Analyzer)
Valve Valve
Valve
Cork Cork
Cork
Gas Volume Measurement(Measuring Cylinder)
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:15th March 2006 to 12th 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.
Treatmentdesignation
Substrate constituentsDilution ratio,Water : Cake
C/Nratio
Substrate concentration
Cake, g
Water, ml
Dung, g
Inoculum, g
Live Absolute % TS % VS
1 1.0 DR [CD] 0.00 2000 2000 200 1:1 11.6:1 22.7 7.9 6.1
Jatropha Oil Cake Substrates
2 3.0 DR [5JC:0CD] 500 1500 0.00 50 3:1 3.4:1 12.7 22.8 21.2
3 3.0 DR [5JC:1CD] 500 1500 100 50 3:1 3.5:1 12.8 22.5 20.7
4 3.0 DR [5JC:2CD] 500 1500 200 50 3:1 3.5:1 12.9 22.2 20.3
5 3.0 DR [5JC:3CD] 500 1500 300 50 3:1 3.6:1 13.1 21.9 20.0
6 3.0 DR [5JC:4CD] 500 1500 400 50 3:1 3.6:1 13.2 21.6 19.7
7 3.0 DR [5JC:5CD] 500 1500 500 50 3:1 3.7:1 13.3 21.4 19.4
8 4.0 DR [5JC:0CD] 500 2000 0.00 50 4:1 4.5:1 12.7 18.2 16.9
9 4.0 DR [5JC:1CD] 500 2000 100 50 4:1 4.5:1 12.8 18.1 16.7
10 4.0 DR [5JC:2CD] 500 2000 200 50 4:1 4.5:1 12.9 18.1 16.6
11 4.0 DR [5JC:3CD] 500 2000 300 50 4:1 4.6:1 13.1 18.0 16.4
12 4.0 DR [5JC:4CD] 500 2000 400 50 4:1 4.6:1 13.2 17.9 16.3
13 4.0 DR [5JC:5CD] 500 2000 500 50 4:1 4.6:1 13.3 17.8 16.1
16
Sl. No.
Treatmentdesignation
Substrate constituentsDilution ratio,water : cake C/N
ratio
Substrate concentration
Cake, g
Water, ml
Dung, g
Inoculum, g
Live Absolute % TS % VS
Pongamia Oil Cake Substrates
143.0 DR
[5PC:0CD]500 1500 0.00 50 3:1 3.7:1 8.7 21.3 20.3
153.0 DR
[5PC:1CD]500 1500 100 50 3:1 3.7:1 8.8 21.1 19.9
163.0 DR
[5PC:2CD]500 1500 200 50 3:1 3.8:1 9.0 20.8 19.5
173.0 DR
[5PC:3CD]500 1500 300 50 3:1 3.9:1 9.1 20.6 19.2
183.0 DR
[5PC:4CD]500 1500 400 50 3:1 3.9:1 9.3 20.4 18.9
193.0 DR
[5PC:5CD]500 1500 500 50 3:1 3.9:1 9.4 20.2 18.6
203.5 DR
[5PC:0CD]500 1750 0.00 50 3.5:1 4.3:1 8.7 19.0 18.0
213.5 DR
[5PC:1CD]500 1750 100 50 3.5:1 4.3:1 8.8 18.8 17.8
223.5 DR
[5PC:2CD]500 1750 200 50 3.5:1 4.3:1 9.0 18.7 17.5
233.5 DR
[5PC:3CD]500 1750 300 50 3.5:1 4.4:1 9.1 18.6 17.3
243.5 DR
[5PC:4CD]500 1750 400 50 3.5:1 4.4:1 9.3 18.5 17.1
253.5 DR
[5PC:5CD]500 1750 500 50 3.5:1 4.4:1 9.4 18.4 16.9
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.
F
A
B1 BC
DD
30 30
15 T
hick
Par
tion
Wal
l
Cen
tral
Gui
de F
ram
e
Fla
nge
Pla
tes
30
15
7.523237.5All dimensions in centimetres
10 D
iam
ter
AS
B/C
EM
Pip
e
10 D
iam
ter
AS
B/C
EM
Pip
e
CC
Fou
ndat
ion
(1:3
:6)
Ear
th F
illin
g
Ground Level
Gas Holder Supporting Structure
Biogas plant (20 m3/d) capacity available at IIT Delhi
20
Development of Special Inoculum
20 m3/d BGP
About 12 m3 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
1 2 3 4 5
Sta
rt of g
as
pro
du
ctio
n
Con
tinu
ed
5 kg pongamia oil cake with 15 kg water for 10 days
Schedule II
Drop in gas yield
6 7 8 9 10 11 12 13 14 15
Increase in gas yield
Constant gas yield (10-15 day) at 30 cm height
10 cm height
2121
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.