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FLUE GAS DESOXSOLUTIONS
19/09/2018
OVERVIEW
• Redecam Power Group Overview• Redecam Air Pollution Control Technologies
Redecam Dry Scrubber (RDS) Pulse Jet Fabric Filter (PJFF) Dry Injection Desulphurisation (DID) Activated Carbon Injection (ACI) Electrostatic Precipitator
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REDECAM GLOBAL REACH
3Projects over 85 countries and on every continent
SOLUTIONS FOR ACID GAS MITIGATION
• Dry Injection Desulphurisation(DSI) -lime or sodium based systems injection system
4May 14, 2015
• Dry (semi-dry) Scrubbing – zero effluent discharge
Redecam Dry Scrubber(CDS)
ACID GAS REACTIONS
• SO2 + Ca(OH)2 CaSO3 + H2O
• SO3 + Ca(OH)2 CaSO4 + H2O
• 2HF + Ca(OH)2 CaF2 + 2H2O
• 2HCl + Ca(OH)2 CaCl2 + 2H2O
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Redecam Dry Scrubbing Technology
DRY SCRUBBING OVERVIEW
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• Redecam Dry Scrubber (RDS)
Redecam Fluidized Bed Technology
REACTOR VESSEL DESIGN
• No Internal Moving Parts Eliminates high speed rotating
atomizer• Improved drying efficiency
SDA water to solids ratio is 2:1 RDS water to solids ratio is 1:20
(5% moisture)• Fast Response to SO2 Fluctuations• Enhanced design supports stable
operation at 50% of flow without gas recirculation
• Extended vessel life with reduced erosion
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THREE PRIMARY CONTROL LOOPS
T – Reactor Temperature control with process water
SO2 – Hydrated Lime injection rate based on SO2 signal
dP – Fluidized Bed control of by-product recirculation
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Boiler
PAC Silo
Fabric Filter
StackID Fan
HydratedLime
Water
Reactor Vessel
TSO2
FabricFilter
dP
Waste Product Discharge
GENERIC DESIGN PARAMETERS FOR RDS
Hold up time
o Flue gas treatment time for coal applications -4 seconds
o Drying CaSO3 and CaSO4
Geometry
o Gas Velocityo Single vetury for small gas flows
o Multiple Venturi higher gas flow
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VENTURI DESIGN
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Bottom Entry View
Top Discharge View
RDS – NO INTERNAL MOVING PARTS
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GENERIC DESIGN PARAMETERS FOR RDS
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• Operating Temperature
o Solids Loading in the Reactor
o Safe Operating Temperature
o (~17 C above saturation)
o Flue Gas Adiabatic Saturation Temperature
RDS DESIGN AND OPERATION CONSIDERATIONS• Removal efficiency up
to > 98-99%+ SO2
removal > 99%+ HCl and SO3
removal > 90% HF removal
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PROCESS WATER INJECTION
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AIR SLIDE BYPRODUCT RE-CIRCULATION
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Simple, Reliable, Few Moving PartsLow Auxiliary Power Very High Mass Flow Capacity
MATERIAL HANDLING
• Air slide technology low energy consumption reliable high flow material handling
• Recirculation injection point is above venturis results in improved operating turndown
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The air chamber (bottom) and
conveying duct (top) are
separated by a porous membrane
DOSING CONTROL VALVE
• Flow control dosing valve installed under each PJFF hopper to control byproduct recirculation
• Reliable solids flow control for proper reactor vessel performance
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RDS EXPERIENCE
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Redecam Dry Scrubber (RDS) Technology – Case Studies
CASE STUDY: NSPCL – 2X20 MW TPP
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CASE STUDY: NSPCL – 2X20 MW TPP
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Dry Injection Desulphurisation(DID) Technology
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DID TECHNOLOGY:
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Reagents: Ca(OH)2, NaHCO3, Mg enhanced lime (FSI) SO2 reduction depending on residence time, moisture in the flue gas,
gas temperature, reagent used, gas-solid mixing, inert dust content, starting baseline
Necessary dedusting downstream multi-injection point possible ideal for retrofit application -> no extra-footprint required
CFD simulation of particle
distribution
DID HYDRATED LIME PROCESS
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Chemical reactions of Hydrated Lime:
Ca(OH)2+ 2HCl → CaCl2 + 2H2O
Ca(OH)2 + SO2 → CaSO3 + 2H2O
2SO2 + 2Ca(OH)2 → 2CaSO3*1/2H2O + H2O
2CaSO3*1/2H2O + O2 + 3H2O → 2CaSO4*2H2O
Ca(OH)2 + 2HF → CaF2 + 2H2O
DID HYDRATED LIME PROCESS:
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• High purity lime over 95% of Ca(OH)2
• Specific surface area measures the total surface area per unit of mass (m2/g, BET method) to take into consideration the hydrodynamic surface + open pores
• Specific porous volume measures the total volume of the open pores per unit of mass (m3/g)
Surface Pore volume Particle size18-20 m2/g ± 0,1 m3/g ± 3 mm22-25 m2/g ± 0,1 m3/g ± 8 mm~ 40 m2/g ± 0,1 m3/g
Standard
Enhanced
Medium
DID HYDRATED LIME PROCESS:
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DID HYDRATED LIME PROCESS:
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DID SODIUM BICARBONATE PROCESS:
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Chemical reactions of Sodium Bicarbonate2NaHCO3 → Na2CO3 + CO2 + H2O (T>150°C)
Na2CO3 + SO2 + 1/2O2 → Na2SO4 + CO2
Na2CO3 + 2HCl → 2NaCl + H2O + CO2
Na2CO3 + 2HF → 2NaF + H2O + CO2
At temperatures >150°C Bicarbonate decomposes to Carbonate, thus increasing greatly the specific surface of the particles
Bicarbonate cannot be stored long time in pulverized form, so a special crusher is used to reduce size just before injection
DID REACTOR
Dosing silo
ESP orBag Filter
Stack
Water
By Product
Dosing system
Gas Flow
DID REACTOR:
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Reactor proposed in case of:
high efficiency required (up to 80%), or lower reagent consumption
required, or layout issues (low residence time)
Main features:
Enhanced residence time
Enhanced gas-solid mixing
Local extraction of deposits and by-products
Venturi zone: reagents injection and mix (gas at 35 m/s)
Reaction zone: in the upper part of the tower
Higher pressure drop (~ 40 daPa) with respect to a simple DID
ADVANTAGES OF DID SOLUTION:
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Low capex solution with very low impact on plant layout.
Very low expected dust emission <10 mg/Nm3 (guarantee value will be 30 mg/Nm3), much lower than required. Usually this kind of result helps Owner’s visibility with local authorities.
DeSOx system flexibility to accommodate different boiler operating load conditions and/or SO2 input figures.
Possibility to reduce reagent consumption.
It is a nice and clean solution.
COMPARISON OF DID AND RDS
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Item DID RDS
Reagent Hydrated Lime Hydrated Lime
Removal efficiency 80-85% 95+
Reagent Quality High Good
Reagent Usage Medium Very Good
Water Injection Yes/No Yes
Pressure Drop Very Low Medium
Foot Print Existing Reactor
Balance of plant impact Low High
DID Technology: Case Studies
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DID CASE STUDY
Hindalco Renusagar – 80 MW Boilers
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6.415 6.400 6.400 6.400 6.415
11.282
Field Inlet Dust 92.700 23.175 5.794 1.738 243 110 Outlet Dust Field Recovered Dust 69.525 17.381 4.056 1.130 134 (mg/Nm3)
Field Efficiency 75% 75% 70% 65% 55%
6.415 6.400 6.400
11.282
Field Inlet Dust 92.700 23.175 6.953 10 Outlet Dust Field Recovered Dust 69.525 16.223 4.519 (*) 5.623 (mg/Nm3)Field / BF Efficiency 75% 70% 65%
(*) Ca(OH)2 Injection (worst case).
OUT
608365
60%
5ESP
Existing ESP
Hybrid Filter + DeSOx
Bag FilterDeSOx:
Reagent injection and Distribution
system
9.615
38.430
9.600
W 1ESP
2ESP
3ESP
5.6332.433
6.400
-3.20099,82%
4ESP
L
L
6ESP
W OUT1ESP
2ESP
3ESP
38.430
RDS & DID Technology: By Product Utilization
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Dry FGD Residue in Coal Fired Power Plants– Typical Composition
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The composition of residue from a DFGD plant also depends on the fly ash content andcomposition as well as the purity of the used lime.
Utilization of DFGD Residue
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The residue of DFGD is used in the following ways:
Fertiliser Re-cultivation Additive for production of screed and mortar Additive for production of gas concrete Additive for production of building bricks. Manufacture of fibreboard Additive for production of lime sand brick Cement coagulation regulator. Additive for binding material. Utilization in road construction. Erection of land filling. Utilisation in the field of surface and underground mining. Production of Anhydrite Conditioning of Sewage Sludge Landfill
Thanks!!!!
Isgec Heavy Engineering LimitedAPCE Division
A-5, Sector – 63,Noida – 201301, U.P
E-Mail: Saurabh.sinha@isgec.co.in/soumik.saha@isgec.co.inM: 9810682195/8826616617
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