1. ENERGY GENERATION FROM BIO GAS PRODUCED AT STP
PRESENTATION ON
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ENERGY GENERATION FROM BIO GAS PRODUCED AT STP
GUIDED BY:
Dr A.B. Gupta
Professor
Civil Department
Presented By:
K M Jaiswal
M.Tech. Ist Sem.
ID-2012 PCE5237

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Excreta and wastewater sludge are resources. Finding ways to put them to their best uses is part of developing sustainable technologies.
At the same time, excreta and wastewater sludge – if not managed properly – can be dangerous to human health and the environment.
Source :-GLOBAL ATLAS OF EXCRETA, WASTEWATER SLUDGE, AND BIOSOLIDS MAGEMENT: UN-HABITAT

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WE CAN GENERATE ELECTRICITY AT PLANT, RUN IC ENGINES AND USE AS FUEL BY BOTTLING THE BIO GAS PRODUCED AT STP DURING ANAEROBIC DIGESTION OF WASTE WATER, WHICH OTHERWISE CAN BE HARMFUL FOR ENVIRONMENT IF ALLOWED TO ESCAPE IN ATMOSPHERE.
BY DOING THIS WE CAN SAVE ELECTRICITY BILL OF STP THERE BY MAKING THEM SULF SUSTAINING
BY REDUCING GHGs WE CAN EARN CARBON CREDITS

4. Case studies (1) 2 62.5 MLD Capacity DELWAS STP in JAIPUR (2) Welissa Farms -- Bantayan, Cebu (3) Anaerobic co-digestion of sewage and brewery sludge for biogas :Thammasat University, Thailand (4) Biogas from Sewage Treatment used to Energy Generation, by a 30 kW (ISO) Micro turbine (5) Bio Gas Production In Indian Perspective (6)Power Generation from gases at STP(Germany) (7)Some case studies to reduce H2s and increase CH contents in Bio Gas
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5. POWER GENERATION AT A GLANCE IN WORLD(2009)
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Country
Total electricity generated (GWhE) [1
Electricity generated from sewage biogas (GWhE) [3]
Population [1]
Electricity from sewage biogas per capita (kWhE)
Percent of total electricity from sewage biogas (%)
Luxembourg
6,500 6
497,500
12.1
0.09
United States
345,000
638
60,587,000
10.5
0.18
Netherlands
124,000
150
16,639,800 9
0.12
Czech Republic
62,000 83
10,256,700
8.1
0.13
3,873,000
2,400
310,232,800
7.7
0.06
Denmark
34,300 38
5,515,500
6.8
0.11
Australia
222,000
125
21,515,000
5.8
Austria
68,300 39
8,214,100
4.7
Poland
129,300
123
38,463,700
3.2
0.1
Sweden
134,500 19
9,074,100
2.1
0.01
France
447,000 45
63,601,000
0.7
Italy
315,000 20
59,715,600
0.3

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Basics of Anaerobic digestion process
Stage of Anaerobic digestion
Factors affecting production of Methane
Power generation units
Bio gas improvement..\power generation\Biomethane power.pdf
Scrubber
Chiller
Gas engine
How to increase methane
Case studies to increase Methane quantity
(reduction of Hydrogen Sulphide methods in various case studies )
Comments on Delawas Power Plant
Case studies referred

7. FROM WHERE CH4 COME FROM………?
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During Anaerobic treatment process of sewage (carried out in the absence of O2) for the stabilization of organic materials CH4 ,CO2, NH3, H2O, H2S are end product .
Organic materials + Nutrients CH4 + CO2 +NH3 + Biomass
Anaerobic microorganisms
Anaerobic processes
Anaerobic fermentation
Anaerobic respiration

8. COD Balance Aerobic Biodegradation
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COD Balance Aerobic Biodegradation
COD Balance Anaerobic Biodegradation

9. Anaerobic digester microbiology
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1:  Extracellular hydrolysis (e.g. cellulose) (page 1) (
2: Fermentation leading to organic acids (VFAs), acetate, CO2 and H2 (page 7-8)
3: Fermentation leading to acetic acid (CH3COOH), H2 and O2
4: Methanogenesis leading to CH4,CO2 and H2O

10. STEPS IN ANAEROBIC DIGESTION
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H2 and CO2
HIGHER ORGANIC ACIDS
COMPLEX ORGANICS
CH4
Insoluble organic material and high molecular weight compounds (lipids, polysaccharides, proteins and nucleic acids) into soluble organic substances e.g. amino acids and fatty acids .Further split during acidogenesis,
ACETIC ACID

11. Overview Anaerobic Biodegradation
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COMPLEX ORGANIC MATTERS
Proteins
Carbohydrates
Lipids
Amino Acids, Sugars
Fatty Acids, Alcohols
hydrolysis
INTERMEDIARY PRODUCTS
(C>2; Propionate, Butyrate etc)
acidogenesis 1 2 3 5 4
Acetate
Hydrogen, Carbon dioxide
Homoacetogenesis
acetogenesis
methanogenesis
Acetotrophic Methanogenesis
Hydrogenetrophic Methanogenesis
Methane
Carbon dioxide

12. FACTORS AFFECTING CH4 PRODUCTION IN ASD
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PH (6.6 TO 7.6) (page 11)
NUTRIENTS AVAILABLITY.
TEMPERATURE (35C TO 55 C) (Page 10)
SOLIDS RETENTION TIME (SRT), (Page 8-9)
VOLATILE FATTY ACIDS (VFA) (page 12,18 -23)
MIXING OF SLUDGE
TOXIC AND INHIBITORY COMPOUNDS ( viz sulphide, light metal cations, ammonia, and heavy metals )

13. FACTORS AFFECTING CH4 PRODUCTION IN ASD ……...
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PRE-TREATMENT PRIOR TO ANAEROBIC DIGESTION : (During hydrolysis, cell walls are ruptured and extracellular polymeric substances are degraded resulting in the release of readily available organic material for the acidogenic micro-organisms. By means of efficient pre-treatment ,the suspended substrate can be made more accessible for the anaerobic bacteria, optimizing the methanogenic potential of the waste to be treated.
Various sludge disintegration pre-treatment: include mechanical grinding, ultrasonic disintegration, chemical methods, thermal pre-treatment, enzymatic and microbial pre-treatments. )

14. BIO GAS PROPERTIES ……………
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S.N.
Properties of Bio Gas 1
Composition
55-70%methane, 30-45%carbon dioxide, .5 TO 2 % H2S , H2O,NH3 and traces of other gases 2
Energy content
kWm-3 3
Fuel equivalent
L oil/m3 biogas 4
Explosion limits
6-12%biogas in air 5
Lgnition temperature ºC 6
Critical pressure
75-89 bar 7
Critical temperature
-82.5 ºC 8
Normal density
1.2kgm-3 9
Odour
Bad eggs (the smell of hydrogen sulphide)

15. Boiling/sublimation point
BIO GAS PROPERTIES………
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Methane
Carbon dioxide
Formula
CH4
CO2
Molecular weight
g/mole
g/mole
4 Å Å
Density (S.T.P.)
kg/m3
1.977 kg/m3
Boiling/sublimation point °C
-78.5°C
Water solubility 20°C
0.035
0.8704

16. POWER GENERATION FROM BIOGAS PRODUCED AT DELAWAS PLANT
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CAPACITY STP MLD UNIT I.
AMOUNT OF GAS GENERATED
FROM ONE 62.5 MLD PLANT : 6000 M3/DAY 250 M3/hr
CALORIFIC VALUE OF GAS : 5000 TO 5600 KCAL/M3
TOTAL HEAT ENERGY OF GAS : KCAL/hr
TOTAL ENERGY IN KW HOUR :
EFFICIENCY OF POWER : 28 %
GENERATION UNIT INCLUDING
ENGINE AND GENERATOR
ELECTRICAL ENERGY PRODUCTION : KWH
EXISTING PLANT PRODUCING BIO GAS CONTINUOUSLY AND EXCESS GAS IS FLARED.
Data made available from Delawas plant

17. LAYOUT OF 62.5 MLD STP AT DELAWAS
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MAIN GATE
PLANTION AROUND THE BOUNDRY WALL
FUTURE SPACE FOR 62.5 MLD (II PHASE)
ROAD
GRIT
SEPERATOR
4 NOS.
PRIMARY
SLUDGE SUMP
GAS FLARING
SYSTEM
MCC
TRANSFORMER
2 NOS
COARSE SCREENS
PRIMARY
SLUDGE
THICKNER
ROAD
INLET CHEMBER
BLOWERS
PMCC CUM
CONTROL ROOM
LAB& OFFICE
BUILDING
SECONDARY
CLARIFIER
2 NOS.
AERATION
TANK
DIGESTERS
2 NOS
RAW SEWAGE
SUMP
FINE MH
SCREENS
RETURN
SLUDGE SUMP
PRIMRY
CLARIFIER
PLANTION AROUND
THE BOUNDRY WALL
OUTLET PIPE
FOR TREATED
WATER
OUTLET
CHEMBER
UNTREATED SEWAGE
FALLING IN NALAH
CENTRIFUGE
UNIT

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Malabar STP process flow diagram ( page 17)

19. REQUIRED FOR ONE ENGINE
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UNITS REQUIRED FOR POWER GENERATION SYSTEM
GAS HOLDER
INTER CONNECTING PIPING
GAS ENGINES
GAS SCRUBBER FOR REMOVAL OF H2 S (By NaOH at Delawas)
CHILLER UNIT : To remove moisture from gas coming gas from the Scrubber through the Blower, by cooling the gas to low temperature by condensing the moisture. A shell and tube type Heat Exchanger will be used for this purpose.

20. Gas Holders at Delawas (Double membrane type)
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21. H2S Scrubber
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22. Biogas upgrading (H2S Scrubbing)
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H2S Removal is needed to
reduce air pollution As it is toxic and odorous and gives sulfur dioxide on burning
protect power generation equipment from corrosion
increase safety of the operations

23. How to minimize H2S in bio Gas
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1. By reducing H2S by Process Control
(a) bio scrubber; bio filter; and bio trickling filter.( H2s is absorbed by Chemotrophic bacteria and elemental sulfur is produced)
2. By Scrubbing, carbon adsorption, and chemical and thermal (page 2)
Oxidation from Bio Gas
Scrubing is being done at DelawasUsing NaoH
H2S gets absorbed in water,
The gas from the bottom of the Scrubber enters the packed Column while liquid is collected in the Tank for recalculation.
In the II stage of scrubbing, gas is scrubbed with caustic solution in a packed Column. The Column is provided with ceramic rings to have enhanced surface area for mass transfer. This is a counter current scrubber and provides high scrubbing efficiency.
caustic solution ensures effective reaction of H2S and CO2 and their removal.

24. Gas Engine
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25. Flaring of excess Gas
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26. SELECTION OF TYPE OF ENGINE
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POWER CAN BE GENERATED FROM BIO GAS FROM
FOLLOWING MACHINES.
DUAL FUEL ENGINE
GAS TURBINE
GAS ENGINE
GAS ENGINE IS MOST SUITABLE AND EFFICIENT FOR PRESENT APPLICATION.
AMONG THE THREE TYPES OF ENGINE GAS TURBINE IS NOT USED FOR BIO GAS FUEL SINCE IT IS NOT SUITABLE FOR LOW CAPACITY.
DUAL FUEL ENGINE IS USED IN REMOTE AREA WHERE NORMAL POWER SUPPLY IS NOT AVAILABLE OR ERRATIC. THIS ENGINE CAN BE RUN EITHER WITH DIESEL OR WITH BIOGAS & DIESEL COMBINATION.
DUAL FUELENGINE NEEDS MORE MAINTENANCE AND DIESEL STORAGE.

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TOTAL GAS GENERATION : 6000 M3/DAY
STORAGE CAPACITY IS
NORMALLY MAINTAINED : 25 % OF TOTAL
IN POWER GENERATION
STORAGE VOLUME REQUIRED : 1500 M3
NO OF GAS HOLDER : 2 FOR EACH 62.5 MLD PLANT
CAPACITY OF EACH GAS HOLDER : 750 M3

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CAPITAL COST : 750 LAKHS
PER KW RUNNING COST : /KW hr
PURCHESE COST OF POWER : Rs 6/- KWhr.
PAY BACK PERIOD : YEARS

29. HOW OPTIMISE GAS PRODUCTION AND OPTIMUM USE OF ENERGY AT STPs
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BY EFECTIVE CONTROL OF PROCESS
AMONIA STRIPPING
THERMAL PRETREATMENT OF SLUDGE BY UTILIZING HEAT OF EXHAUST GASES
SCUM AND GREASE CAN BE FED IN DIGESTER
USE THERMOPHILIC STAGE FOR MORE GAS PRODUCTION BUT THIS NEED EFFECTIVE CONTROL
BIOLOGICAL REMOVAL OF SULPHER SO THAT H2S PRODUCTION CAN BE MINIMISED
IN WINTER DUE TO LOW ATMOSPHERIC TEMPERATURE GAS GENERATION IN DIGESTER IS REDUCED.
OTHER COST EFFECTIVE TECHNOLOGIES CAN BE USED TO REDUCE HYDROLYSIS TIME AND OVER ALL SRT OF ANAEROBIC PROCESS, MINIMIZATION OF TOXICANTS AND INHIBITION FACTORS TO INCREASE QUALITY AND QUANTITY OF BIO GAS.

30. THANK YOU
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QUESTIONS ?

31. Downloaded from CivilDigital.com Complex organic material
(starch, protein fats)
Hydrolysis
Simple organic material
(sugar, amino acids)
Acidogenesis
Volatile fatty acids
(propionate, butyrate etc.)
Acetogenesis
Acetate
H2 + CO2
Methanogenesis
Methanogenesis
CH4 + CO2

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Overall process of anoxic decomposition, showing the manner in which various groups of fermentative anaerobes cooperate in the conversion of complex organic materials ultimately to methane 1 CH42 and CO2. Acetate and H2 + CO2 from primary fermentations can be directly converted to methane, although H2 + CO2 can also be consumed by homoacetogens. But note how the syntrophs play a key role in anoxic decomposition by consuming highly reduced fermentation products in a secondary fermentation. By activities of the syntrophs, fatty acids and alcohols are converted to the substrates for methanogenesis and acetogenesis. This picture holds for environments in which sulfate-reducing bacteria play only a minor role, for example, in freshwater lake sediments, sewage sludge bioreactors, or the rumen. If alternative electron acceptors are abundant, as for example, sulfate in marine sediments, anaerobic respiration prevails, as syntrophs cannot compete for fatty acids/alcohols with sulfate-reducing bacteria or bacteria carrying out other forms of anaerobic respiration.
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Figure: 19-24
Caption:
Overall process of anoxic decomposition, showing the manner in which various groups of fermentative anaerobes cooperate in the conversion of complex organic materials ultimately to methane 1CH42 and CO2. Acetate and H2 + CO2 from primary fermentations can be directly converted to methane, although H2 + CO2 can also be consumed by homoacetogens. But note how the syntrophs play a key role in anoxic decomposition by consuming highly reduced fermentation products in a secondary fermentation. By activities of the syntrophs, fatty acids and alcohols are converted to the substrates for methanogenesis and acetogenesis. This picture holds for environments in which sulfate-reducing bacteria play only a minor role, for example, in freshwater lake sediments, sewage sludge bioreactors, or the rumen. If alternative electron acceptors are abundant, as for example, sulfate in marine sediments, anaerobic respiration prevails, as syntrophs cannot compete for fatty acids/alcohols with sulfate-reducing bacteria or bacteria carrying out other forms of anaerobic respiration.