Pine Process Fundamentals

8/6/2019 Pine Process Fundamentals

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Anaerobic Digesters:Process Fundamentals andEnvironmental Emissions fromPig Farms

JESSE M. PINEJESSE M. PINE

SRS II, DOST-PSTC-Oriental Mindoro


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Hyu Hlafus!


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BACKGROUND


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Philippine Livestock Production for 2005-2007


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Recent Growth in the Swine Industry in the Philippines


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Swine Industry Performance Report (January, 2010-BAS)

Swine Inventory 13.4 million heads

71% raised in backyards

29% raised in commercial farms


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Waste Management Scenario


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Conventional Waste Management Schemes

DIRECT DISCHARGE


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LAGOON


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FISHPOND


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SETTLING PONDS


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MANURE PILING


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ANAEROBIC DIGESTION


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Stages of Anaerobic Digestion

(Methane Production)


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BIOGAS PRODUCTION PROCESS

ANIMAL WASTE

HUMAN WASTE

CROP

RESIDUES

OTHERORGANIC

WASTES

DIGESTER

BIOGAS

SLUDGE

CH4 (60-70%)

CO2 (30-40%)

H2S (Traces)

O2 (Traces)

CO (Traces))

Solid (10-20%)

Liquid (80-90%)


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Anaerobic Digestion at a Glance

biological

process

organicmatter

degradation

(oxygen-

free)

biogas


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Advantages of Anaerobic Digestion

Economic advantages: Revenue from sale of carbon credits

Reduction of manure purchase

Lowers demand for natural gas and fossil fuel

thus saving precious dollars

Fully renewable


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Agronomic advantages:

Improves agri / agro-waste management

Reduces build up of manure solids in farm

storage lagoons

Recycles fiber for use in bedding or soil

enhancements

Conversion of the liquid manure and the solid

manure fertilizer


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Environmental advantages:

Reduces GHG emissions (captures and utilizesmethane gas from manure thus making air of better

quality)

Improves soil and water treatment (controls

pathogenic bacteria in soil and surface watersupplies)

Reduces piggery odor and inhibits pollution

Insect elimination at the storage pit Sustainable management of organic waste


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What are Anaerobic Digesters?

Biological treatment/stabilization systems

Applicable to liquid, slurry, and semi-solid

waste that collect and combust off-gases.

Digesters separate manure treatment from

storage functions which can result in lower

initial installation costs for new o expanding

farms.


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Types of Anaerobic Digesters

1. Micro digester

Fixed-dome type

Bag-type

Portable type

2. Advanced Systems

Covered lagoon

Complete mix

Upflow digesters

High solid digesters


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Principles of Digester Sizing

Maintain microbial populations by balanced acid phase

with methanogenic phase

Control acid and methanogenic phase with HRT and

Loading Rate

HRT = Hydraulic retention time = digester volume

(V, m3) / daily influent volume (Q, m3/day)

Loading rate is the amount of volatile solids (VS) put

into the system

HRT is temperature dependent


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Critical Digester Sizing Parameters

Hydraulic Retention Time (HRT)

the residency time (days) that manure and process

water (influent) remain in the lagoon to achieve

waste stabilization and maximum methaneproduction.

Lagoon may be retention-time limited when

high volumes of process water are used.


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Critical Digester Sizing Parameters

Loading Rate

The mass of organic load per unit lagoon volume

lbs. VS/1,000 ft3 lagoon volume or kg/1,000 m3lagoon volume

Lagoon may be loading rate-limited when low

volumes of process water are used.


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ENVIRONMENTAL EMISSIONS


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Volatile Solids manure constituent generally representative of the organic

matter content excretion rates vary with breed and feeding practice

2006 IPCC* VOLATILE SOLIDS EXCRETION RATE DEFAULT VALUES,

KG/HEAD-DAY, FOR BREEDING AND MARKET SWINE

*Intergovernmental Panel on Climate Change


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Maximum Methane Production Potential

*Intergovernmental Panel on Climate Change

The maximum methane production potential (Bo) is

an experimentally determined estimate of the

maximum volume of methane that will be produced

per unit mass of volatile solids under anaerobicconditions.

Bo varies with animal species and feeding

practices. IPCC default values are listed below.


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Maximum Methane Production Potential


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Methane Conversion Factor

An estimate of the fraction of Bo that actually

will be converted to methane as a function of

temperature and manure management

practice.

Varies by manure management system and

climate. Generally, 90 percent should be

assumed for anaerobic digestion.


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Methane Conversion Factor


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Gas Production

Based on the VS and B0, and assuming a 90 percent

MCF for a covered anaerobic lagoon, the estimated methaneproduction values for swine are:


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Methaneredu

ction,m3/year


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Fixed-dome Digester

waste

and

water

slurry

gas hydraulic

pressure

tank

settling ponds

biogas pipeline

service

area

piggery

cover

cover


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DOST-Assisted Biogas Adoptors in Five

Regions of the Country (2009)

REGION Number of

Biogas Facilities

AggregateDigester

Capacity

(cu. m.)

Annual Biogas

Production

Region 1 2 50 9,125 m

Region 2 1 12 2,190 m

Region 3 74 1,056 192,741 m

Region 4A 109 1,650 301,158 m

Region 4B 54 489 89,252 m

Totals 240 3,257 594,466 m


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Annual Biogas Production and its

Equivalent to LPG in Tanks (2009)

REGIONAnnual Biogas

GeneratedEquivalent

LPG tanks

Amount

(pesos)

Region 1 9,125 m 333 216,450.

Region 2 2,190 m 80 52,000.

Region 3 192,741 m 7,034 4,572,100.

Region 4A 301,158 m 10,991 7,144,150.

Region 4B 89,252 m 3,257 2,117,050.

Total 594,466 m 21,695 14,101,750.


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Biogas Utilization in Oriental Mindoro

Cooking Lighting


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Brooding House Heater


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Quick Facts

A 1 cu. m. biogas facility can produce 0.40 cu. m.

methane daily

A person needs only 0.25 0.30 cu. m. biogas in

daily cooking

An ordinary stove requires 0.425 cu. m. biogas daily

An LPG or Biogas-fed engine needs 0.425 cu. m.

biogas every hour


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Quick Facts

A light bulb requires 0.15 cu. m. biogas per hour while a3HP engine needs 0.28 cu. m. biogas per hour

An 11-kg. LPG tank is equivalent to about 16 cu. m.

biogas

One (1) cu. m. biogas is equivalent to 0.5 - 0.6 liter

kerosene

Butane (C4H10) and Propane (C3H8) in LPG tank are

readily combustible than biogas or methane (CH4)


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Quick Facts

Odor Slight odor

Color Colorless but turns blue (as LPG) while

burning

Weight Lighter than air

Energy One (1) cubic meter biogas has 5,000-6,000kcal heat which is equivalent to: 600ml

kerosene in stove, 1.5kgs charcoal and

3.5kgs fire wood

Composition Methane (CH4), 60-70%

Carbon dioxide (CO2), 30-39%, Other gases, 1-3%


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Methanes global warming potential

is 21 times as potent as CO2in warming the

earth

it stays in the atmosphere for

about

12 years!


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Tey bong

nawa hukuy!

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Pine Process Fundamentals