Biogas Engr. Baral

7/30/2019 Biogas Engr. Baral

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BIOGAS:GENERATION,UTILIZATION

AND PIPING SYSTEMEDWIN B. BARAL rmp/ce

Chair, University Technical Working GroupPhysical Plant and Site Development Services

Nueva Vizcaya State University

Bayombong, Nueva Vizcaya


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Introduction:

Biogas is a major by product of anaerobicprocesses. All decaying organic matters

produced biogas when it undergoes

decomposition. The process of decompositioneven without the presence of oxygen isanaerobic decomposition. Anaerobic digestion

is a process of allowing bacteria to allowbacteria to grow through metabolic process offermentation where organic materials is brokendown.


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Biogas is produced when bacteria digestbiomass in condition when air is lacking. Garbage

buried deep in the land fill produces biogas andany biodegradable materials place in air tight tanksor Anaerobic digesters

Biogas A mixture of gases, about two thirds

methane & other one third is made up of carbondioxide, water vapor and small proportion ofother gases.


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Biomass Method to change plants andanimal materials into high quality fuel.

- It can be use directly as fuel

- It can be carbonized first and then used as

fuel.

- To produced ethanol yeast is added for a

biomass placed inside a container to changesugar into ethyl alcohol.


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Methane, the simplest HydrocarbonA carbon atom has four valence electrons

and forms for covalent bonds. Therefore, thesimplest hydrocarbon consists of one carbonatom to which four hydrogen atoms are bonded.

The C-H bonds in this simplest hydrocarbon,

called methane, are formed from tetrahedrallydirected sp3 hybrid orbitals on the carbon atom.

You can represent the structure of methane by its

molecular formula, CH4, which gives the numberand kind of atoms in the molecule, or by itsstructural formula, which shows how the atoms

are bonded to one another: (Ebbing and Gamon, General Chemistry,6th edition, Houghton Mifflin Company, 1999)


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Adapted from Robert D. Whitaker et al., Concepts of General, Organic and Biological, p.231 as

cited byEbbing and Gammon, General Chemistry, Sixth Edition p.1038, published by: HoughftonMifflin Com an 1999


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Why is it necessary to tap biogas as

an alternative source of energy?

It is a renewable energy

It is better to burn the methane than let it

escape in the atmosphere because its heattrapping effect is 21 times than that of CO2(Methane is 21 times harmful than CO2)

It is a contributory factor in global warming astwo thirds of biogas is methane


10/27Source: Nebel & Wright, Environmental Science, 6th Edition, Prentice Hall, 1998, p.412

Anthropogenic Greenhouse Gases in

the Atmosphere


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Anthropogenic - referring to the pollutantsand other forms of impact on natural

environments that can be trace to humanactivities

Greenhouse gasses- Gases in the atmospherethat absorb infrared energy and contribute to

the air temperature. These gases are like a heat

blanket and are important in insulating Earths

surface. They include CO2, water vapor, CH4,

N2O, and CFCs and other halocarbons.


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Why we have to tap biogas from land fill

and sewage treatment facilities

To control methane gas emission into

the atmosphere As a source of alternative energy

Ratification of Kyoto Protocol

Proper waste management & sewage

effluent treatment


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Energy Flow Diagram

(Biogas from Landfill)


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Energy Flow Diagram

(Biogas from Anaerobic Digester)


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How much biogas can recover from

garbage on landfill

Landfill biogas recovery = landfill biogas

generation x collection efficiency

Methane generation potential of garbage:

depends on the quantity of volatile solid

present , type of waste, acidity/alkalinity


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Energy Flow Diagram

(Household Application)


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Estimated Biogas per kilogram of

waste/manure

1. Swine (pig)manure - 3.75 kg/head per day

estimated quantity biogas in cubic meters:

0.0403 m3/kg - 0.0504 m3/kg

2. Cow/Bufallomanure 8 -12 kg/head per day

estimated quantity biogas in cubic meters:

0.023 m3/kg - 0.04 m3/kg


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Required Diameter of Gas Pipe from

Processed Biogas

By Darcy-Weisbach Equation

D = f L V2 / 2 hL gwhere: f = frictional factor

hL= head loss

L = length of processed biogaspipe

V= flow velocity of processedbiogas

g = acceleration due to gravity


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Gas Requirements for Some AppliancesSource: Philippine Agricultural Engineering Standard, 2002

Appliances (Type) Gas Requirements(m3/h

1. Gas Burner (non-continuous)

5 cm, 10 cm, 14 cm - 0.2267; 0.2800; 0.42002. Mantle Lamp (non-continuous)

ordinary lamp - 0.0710

25-watt equivalent - 0.100060-watt equivalent - 0.1950


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Cont.

3. Gas Refrigerator (continuous)

0.01 m3 - 0.0530

0.17 m3 - 0.0670

0.225 m3

- 0.0780

4. Engine (per KW output)

gasoline (non-continuous) - 0.5690diesel (non-continuous) - 0.7000


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List of Companies

SCS ENGINEERS (Environmental Consultants andContractor, http//www.scsengineers.com/)

FIRST BALFOUR (A Lopez group of company,

www.firstbalfour.com) BIOGAS TECHNOLOGY (INDIA) PVT.LTD

(http://www.biogasindia.com/services.html)

CHENGDU ENERGY- ENVIRONMENT

INTERNATIONAL CORPORATION (CEEIC) China APPLIED FILTER TECHNOLOGY INC.- company that

design construct and built LFG processing system thatremoved CO2 and contaminants from gas stream.
http://www.biogasindia.com/services.htmlhttp://www.biogasindia.com/services.html


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Biogas Engr. Baral