Transcript Document

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MUNICIPAL SOLID WASTE (MSW)
• MATERIAL RECOVERY FACILITY(MRF)
• WASTE TO ENERGY PLANT(WTE)
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WHAT IS
TYPICAL
GARBAGE ?
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AVERAGE WASTE CHARACTERISTIC FOR
GARBAGE (% BY WEIGHT)
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CURRENT LOGISTICS IN MSW HANDLING
AND TREATMENT
COLLECTION
RESIDENTIAL
TRANSFER STATION
LANDFILL
TRANSFER
STATION
(VOLUME
REDUCTION)
COMMERCIAL
LARGE OBJECTS,
CONSTRUCTION MATERIALS, ETC.
LANDFILL
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PROPOSED REPLACEMENT OF
TRANSFER STATION WITH
MATERIAL RECOVERY FACILITY (MRF)
WASTE TO ENERGY PLANT (WTE)
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THERMAL REDUCTION STATION
COLLECTION
WASTE TO ENERGY PLANT
MRF
LANDFILL
Main stream
Urea
injection
RESIDENTIAL
Material
Recovery
Facility
CONNECT TO
TNB GRID
Turbine
RSF
EnvirOcycler
Fuel Input
COMMERCIAL
Heat
Recovery
Boiler
External
Dust
Control
Dioxin
Control
Unit
ID FAN
Chimney
Steam for
ejector
ID EVAPORATIVE
COOLING
TOWER
STEAM
CONDENSER
0.2
BARs
HOT
WELL
STORAGE
Cooling water
return
Gasification/
Combustion air
Water
evaporation
loss
CIRCULATION
WATER
PUMPS
Feed Water Pumps
2 x 100% capacity
pumps
CONDENSATE EXTRACTION PUMP
DEARATOR
MAKE UP WATER PUMP
-2% of feed water
-2 x 100% capacity)
Cooling
water flow
Cooling water Pumps
(2 x 100% capacity)
DM
Water
Tank
BLOW DOWN
-1% of circulation
water
Cooling water
make up pump –
3% of circulation
water
DM Plant
cap=-3%
feed water
BOTTOM ASH
LARGE OBJECTS CONSTRUCTION MATERIALS ETC.
LANDFILL
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100% MSW
BIG OBJECTS
BAG SPLITTER
PLASTICS ( 8-10%)
PICKING LINE
FERROUS
3%
NON-FERROUS
0.9%
RECYCLING AND
REFUSE
SEPARATED FUEL
(RSF) PLANT
SHREDDER
TROMMEL
30% FOOD WASTE/
ORGANICS (TO LANDFILL
OR COMPOSTING )
RSF
STORAGE OF RSF
2 TO 3 DAYS STORAGE
TO HEAT PLANT
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WHAT IS RSF FUEL
IT HAS:-
• LESS FUEL PREPARATION
• MOISTURE AROUND 60 – 65 %
• LOW CALORIFIC VALUE < 1500KCAL/KG
• HIGH ASH CONTENT
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RSF TO BE GASIFIED IN A 2- STAGE
GASIFIER WITH CHARACTERISTICS
:
- HIGH MOISTURE CONTENT
- LOW CALORIFIC VALUE
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EnvirOcycler
More photos
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EnvirOcycler

1st Stage: gentle updraft gasification on very
large grate
 2nd Stage: vigorous, double vortex, cyclonic
combustion
 Emissions: CO < 1ppm, NOx < 15 ppm,
particulate < 100 mg/Nm3 (< 0.125 lb/106
Btu; < 0.04 gr/dscf)
 Units in continuous operation for 29 years
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FUEL SOURCE

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Separated MSW (RSF)
Empty Fruit Bunch(EFB)
Saw Dust & Timber Waste
Partially Dried Municipal Sewage Sludge
Rice Husk
Cattle Manure
Pig Manure
Poultry Litter
Etc.
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SIGNIFICANT FEATURES, 1
Four air sources:
 Underfire air gasifies biomass in the 1st stage
 Overfire air preheats 1st stage producer gas to
ensure ignition in the 2nd stage
 Primary combustion air ignites the preheated
producer gas at the bottom of the 2nd stage
 Secondary combustion air completes
combustion of producer gas in the 2nd stage
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SIGNIFICANT FEATURES, 2
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Very large 1st stage grate area
o
Resulting in grate temperature < 650 C
Essentially zero slag
Very low underfire air flow
(to gasify RSF/ Biomass)
Therefore, very low particulate carry-over
from pile
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SIGNIFICANT FEATURES, 3

Staged combustion permits operating
excess air levels to as low as 15%

Staged combustion and low temperatures
(due to wet fuels) combine to produce
virtually zero thermal NOx
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SIGNIFICANT FEATURES, 4

Dioxins and Furans Destroyed
 Chlorine can react with cellulose to form
dioxins and furans in the 1st stage
 However, these gases are destroyed in the 2nd
stage at 1,100oC
 No black waterwalls are present to chill – and
lock in - dioxins or furans in the 2nd stage
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SIGNIFICANT FEATURES, 5

The EnvirOcycler can burn RSF and
Biomass with moisture contents up to 65%
(wet basis) and ash contents up to 35%
 5:1 turndown ratio is standard; 9:1 is not
uncommon
 15 second response time to step change in Btu
Demand signal
 Abort valve permits rapid dumping of
products of combustion in an emergency
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What About Alkali deposits?

When agricultural waste was burned in wood
residue boilers, boiler tubes became coated with
slag-like deposits
 The deposits were due to condensed salts of
Potassium (K) and Sodium (Na)
 K (vapor temp = 760oC) and Na (vapor temp =
o
880 C) vaporized off the potash and soda in the
o
ash on the 980 C – 1,100oC grate
 K and Na then formed salts with chlorine and
sulphur compounds in the furnace gases
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Deposit Buildup

The K and Na salts condensed and formed
sticky, flypaper-like coatings on the boiler tubes
 Particulate lifted off the grate fuel pile, and up
through the furnace by rising products of
combustion, adhered to the coated tubes
 A progressive buildup of alkali deposits ensued,
particularly at a change in the flow path of the
gases through the boiler
 Hence the term “alkali deposits”
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Alkali Deposits – Not in
EnvirOcycler
Because the EnvirOcycler’s grate temperature
o
does not exceed 650 C, K and Na do not vaporize
 Rather, K and Na remain as potash and soda on
the EnvirOcycler’s grate and are removed by the
built-in ash removal system
 Similarly, phosphorus in poultry litter, the
suspected cause of Pfiesteria outbreaks, also
remains on the EnvirOcycler’s grate

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ELEVATION
WASTE HEAT RECOVERY BOILER
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More photos
WASTE HEAT RECOVERY BOILER
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SELF-REGULATING
BRUSHLESS
GENERATOR
(TYPICAL)
TYPICAL STEAM TURBINE
More photos
- Steam consumption rate - 4.3 kg/hr
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EMISSIONS CONTROL
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FABRIC BAG FILTERS
Fabric filter with cleaning by back-flushing
COLLECTION PRINCIPLE
When dust-laden gases flow
through a porous fabric, the
dust is separated from the
carrier gas and deposited on
the filter colth. It is removed
periodically and falls into the
dust hopper.
OBJECTIVE
To reduce particulate
emissions to less than
10mg/Nm3
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DIOXIN REMOVAL-PRESENT TECHNOLOGY
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SUMMARY: SHELL DIOXIN DESTRUCTION SYSTEM
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COMPARISON OF SDS VERSUS HONEYCOMB
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COMPARISON OF SDS VERSUS HONEYCOMB
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CRI SCR REACTOR SYSTEM
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TYPICAL DIOXIN DESTRUCTION PERFORMANCE
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EMISSIONS
Particulate
CO
NOx
Dioxin
<
<
<
<
10 mg/Nm3
1 ppm
80 mg/Nm3
0.1 mg/Nm3
VORTEX EFFECT
IN EnvirOcycler
CLEAN HEAT
EMISSION
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