Upload
others
View
5
Download
0
Embed Size (px)
Citation preview
WÄRTSILÄ
EXHAUST GAS CLEANING
SOX/Scrubbers
30 March 2015 WÄRTSILÄ ENVIRONMENTAL SOLUTIONS PRODUCTS / MORTEN LETNES 1 © Wärtsilä
NOx
Acid rains
Tier II (2011)
Tier III (2016??)
SOx
Acid rains
3.5% (2012)
ECA 0.1% (2015)
CO2
Greenhouse
gas
Under evaluation
by IMO
Emissions and Environment
2 © Wärtsilä. STRICTLY CONFIDENTIAL. This document is the property of Wärtsilä Corporation and shall not be copied or reproduced without the consent of the owner.
Doc.ID: Revision: Status: 51 / © Wärtsilä
IMO SOx Emission Control Areas
30 March 2015
Options for SOx
CHANGE TO MGO
Run full time on Marine Gas Oil
(MGO).
Convenient
No change over
High operating cost
Future availability?
CONVERT TO LNG
Convert engines to run on gas
(LNG).
A solution which also reduces
NOx and particulates
Investment cost
LNG availability
USE SCRUBBERS
Install an exhaust gas
cleaning system (scrubber).
Works with high S HFO
Lowest total lifecycle cost
Use everywhere
Easy operation
ROI depends on fuel oil price
difference between low S fuel
oil and high S HFO
FUEL SWITCH
Switch to low sulphur fuel in
SECA.
Flexible
Small investment
High operating cost in SECA
Fuel change over procedures
Lube oil TBN management
Fuel availability?
Seawater scrubbing system chemistry
Engine Exhaust Chemistry:
S + O2 → SO2 (~95%)
SO2 + 1/2 O2 → SO3 (~5%)
Scrubber Chemistry:
SO2 + H2O → H2SO3 (Sulphurous Acid)
SO3 + H2O → H2SO4 (Sulphuric Acid)
Scrubber Reactions:
CaCO3 + H2SO3 → CaSO3 + H2O + CO2
2CaSO3 + O2 → 2CaSO4 (Calsiumsulphate)
Alkalinity (Bicarbonates (HCO3-) and carbonates (CO3
2-))
– neutralize and help to buffer the pH rapidly
Doc.ID: Revision: Status: 51 / © Wärtsilä
Example alkalinity level
30 March 2015 6 Wärtsilä Scrubber Systems / J.Snickars
Scrubber approval alternatives according to IMO
SCHEME A – Exhaust gas cleaning (EGC) system approval, survey and
certification using parameter and emission checks
• Compliance demonstrated by emission tests
• Possible to obtain for serially manufactured units and for a certain
production range
SCHEME B – Exhaust gas cleaning (EGC), survey and certification using
continuous monitoring of SOx emissions
• Compliance demonstrated in service by continuous exhaust gas
monitoring
Wärtsilä Scrubber Types
Yes No Partly
No Yes Partly
OPEN LOOP
Ocean-going ships
Low-alkalinity waters
and for zero discharge
Ships operating in
both types of waters
or requiring full
flexibility of operations
CLOSED LOOP HYBRID
Seawater NaOH NaOH / Seawater
Dependable on
seawater alkalinity
Zero discharge
possible
Applications
Alkaline reactant
30 March 2015 8 Wärtsilä Scrubber Systems / J.Snickars
Selection according to
the Ship Op Profile
30 March 2015
9
30 March 2015
Closed Loop Scrubber System
30 March 2015
SOx Scrubbers and Survey Schemes
12 © Wärtsilä This document is the property of Wärtsilä Corporation and shall not be copied or reproduced without the consent of the owner. © Wärtsilä
Freshwater closed loop Seawater open loop Hybrid (seawater closed
loop)
Not dependent on seawater alkalinity
Dependent on seawater alkalinity (issue for limited
areas such as lakes, few ports close to estuaries,
Northern and Eastern part of Baltic Sea; limitation:
1000 umol / L)
Possibility to operate independently from
seawater alkalinity for a limited period (
limitation: 1000 umol / L)
Zero effluent discharge for some time No possibility for zero discharge Zero effluent discharge for limited period
Needs caustic soda as a reagent
No need of NaOH (and logistics) Needs caustic soda for intended closed
loop operations
Low power demand (0,5-1,0 % additional
engine power demand)
Slightly higher power demand (2,0 % additional
engine power demand)
Slightly higher power demand (2,0 %
additional engine power demand)
Slightly more complex system Simple system Slightly more complex system
Needs FW (possibility to use AWP treated
water)
No need for additional FW No need for additional FW
No issues related to sea chests Sea chest capacity (retrofits) Sea chest capacity (retrofits)
More tank requirements (alkali, buffer tank,
holding tank, sludge tank)
Lower tank space demand (residence tank, sludge
tank)
More tank requirements (alkali, 2x
residence tanks, holding tank, sludge tank)
Types of Scrubber Units
30 March 2015
Scrubber with venturi
• SOx reduction from
3,5% to 0,1%
• PM reduction up to
80%
• By-pass needed
• Existing silencer
recommended to be
kept
Inline scrubber
• Smaller footprint
• No by-pass – can
run hot
• Pressure drop at
design: 150 mm
WG
• SOx reduction
from 2,5% to 0,1%
• Can replace
silencer
Wärtsilä Integrated Scrubber
1
3
4
5
2
6 7
8
9
1. Diesel engine
2. Oil-fired boiler
3. SCR
4. Exhaust gas boiler
5. Silencer
6. By-pass valve
7. Exhaust gas manifold
8. Scrubber unit
9. Exhaust gas fan
Main features
• For diesel engines and oil-fired boilers
• One common scrubber unit with suction fan for all
combustion units onboard
• Suction branches with by-pass valves from all
exhaust gas and flue gas pipes
• Constant under-pressure at scrubber inlet
prevents undue flow of gases
Benefits
• Completely avoids increased exhaust gas back
pressure
• Minimizes the amount of equipment
Ideal for
• Single engine cargo ships with HFO gensets
• Multi engine ships
• Tankers with large boilers
14 © Wärtsilä. STRICTLY CONFIDENTIAL. This document is the property of Wärtsilä Corporation and shall not be copied or reproduced without the consent of the owner.
Sludge Seawater Systems
The collected sludge:
Non-hazardous by legislation
To be disposed of ashore
Can be disposed with the vessels waste oils/sludge
Estimated amount closed loop: 2 l/MWh
Estimated SFOC use ~ 0.1 g/kWh
The amount depends on silt content in water and engine running profile
Sludge is collected in standard 1m3 plastic container
Example – APL England
• Vessel : APL England
• Size of SWS : 1 x 8 MW with 3 inlets
Each inlet for a 2,94 MW
engine
• Installation type Retrofit
• Delivery : January 2011
• Performance :
– 97% SOx Removal
– 85 % Particulate Removal
– 3,5% fuel sulphur content
An installation in cooperation with Port of Long Beach and APL
Wärtsila Inline Scrubber
17 © Wärtsilä This document is the property of Wärtsilä Corporation and shall not be copied or reproduced without the consent of the owner.
Scrubber Retrofit
For existing ships, the retrofit of a scrubber requires tailor-making.
Some aspects to be considered for retrofits are:
• Space; design of exhaust gas funnel
• Ship stability
• Space available for tanks, pumps and water treatment unit(s)
• Power demand for the scrubber system
• Sea chest , capacity of supplying water to the scrubber system
• Fresh water capacity (closed loop and hybrid scrubber only )
NaOH Consumption
Alkali Consumption
References Summary
21
Closed loop Open loop Hybrid Total
10
25
30
65
Scrubber Reference Installations
Closed loop Open loop Hybrid Total
As at End of 2014
WÄRTSILÄ
EXHAUST GAS CLEANING
NOX/SCR
30 March 2015 WÄRTSILÄ ENVIRONMENTAL SOLUTIONS PRODUCTS / MORTEN LETNES 22 © Wärtsilä
Revised Marpol Annex VI Regulation 13
Tier I >130 kW New ships 2000
Tier II >130 kW New ships 2011
Tier III >130 kW Upcoming requirement, New ships inside Emission Control Areas (ECA)
Rated engine speed (rpm)
0
2
4
6
8
10
12
14
16
18
0 200 400 600 800 1000 1200 1400 1600 1800 2000
NOX (g/kWh)
Wärtsilä NOR operation area
Primary methods operation area
Secondary methods operation area
18 February 2014
Wärtsilä standard NOR is dimensioned for reaching the IMO Tier 3 level.
23 © Wärtsilä Wärtsilä NOx Reducer
NOX formation and reduction
• Nitrogen Oxides (NOx) are formed during the combustion process
from oxygen (O2) and nitrogen (N2) in air.
• In atmosphere NOX reacts to form smog, acid rain and ozone.
• The Wärtsilä NOX Reducer SCR catalyst converts NOX molecules
back to harmless water (H20) and nitrogen (N2) molecules by means
of urea.
18 February 2014 Wärtsilä NOx Reducer 24 © Wärtsilä
Engine exhaust
Urea injection
Wärtsilä NOX Reducer – Description
• The Wärtsilä NOx Reducer (NOR) is based on selective
catalytic reduction (SCR) technology.
• The NOR is optimized and validated for Wärtsilä medium
speed engine portfolio for marine applications in terms of
reliability, flexibility and size. It is available for both distillate
and heavy fuel oils.
18 February 2014 Wärtsilä NOx Reducer 25 © Wärtsilä
Main components
Injection and
Mixing unit
Reactor Soot blowing unit
Catalyst elements
Control unit
Pump unit Air unit
Dosing unit
18 February 2014 26 © Wärtsilä Wärtsilä NOx Reducer
Reactors availabe in different shapes for
flexible and easy installation
Short and wide 2 layers
vertical reactor
Long and narrow 3 layers
vertical reactor
Short and wide 2 layers
horizontal reactor Long and narrow 3 layers
horizontal reactor
18 February 2014 27 © Wärtsilä Wärtsilä NOx Reducer
NOX reduction functional principle (SCR)
Operating temperature
~ 300 – 450 °C
Nitrogen oxides (NOX) are
reduced into nitrogen (N2) and
water vapour (H2O) using
ammonia or urea at a suitable
temperature on the surface of the
catalyst.
18 February 2014 28 © Wärtsilä Wärtsilä NOx Reducer
Wärtsilä NOx Reducer - System overview
18 February 2014 Wärtsilä NOx Reducer 29 © Wärtsilä
System overview - Multiple installation
18 February 2014 Wärtsilä NOx Reducer 30 © Wärtsilä
The control unit, air unit and pump
unit are centralized units, meaning that same
units can be utilized in multiple NOR installations.
Minimum recommended temperature in the SCR
inlet vs fuel sulphur content
18 February 2014 31 © Wärtsilä Wärtsilä NOx Reducer
Optimised engines for specific requirements
• Majority of the Wärtsilä engines have been
tuned to fulfill SCR temperature
requirements
• The tuning is done to minimize the effect
on SFOC or thermal load
• Temperature control strategies include:
– Air waste-gate control
– Exhaust gas waste-gate control
– Air by-pass control
– Valve timing
• Majority of the Wärtsilä engines have been
developed to cope with a higher back
pressure tolerance
– Install several exhaust gas equipment
– Install smaller equipment
18 February 2014 32 © Wärtsilä Wärtsilä NOx Reducer
Wärtsilä NOR performance
• Compact and Flexible design
• Optimized and validated system
• Efficient SCR process
• Durable catalyst elements
• Possibility to integrate NOR reactor
with silencers
Performance
NOx emission levels as per IMO Tier III as standard
Other NOx levels upon request
Urea consumption (40% solution)
Typically 15 l/h / MW
Operation
Fuels: MGO / MDO / HFO
Compatible with SOx scrubber systems
Typical noise reduction for the NOR reactor: 8-10 dB(A)
18 February 2014 Wärtsilä NOx Reducer 33 © Wärtsilä
Integrated silencer
SCR reactor
Integrated SCR reactor + silencer + spark arrestor
Integrated spark arrestor
22 January 2015 34 © Wärtsilä
Urea solution
18 February 2014
• Safe carrier of reducing agent ammonia (NH3)
• Classified as non toxic and non dangerous goods
• Decomposes to ammonia when exposed to heat (+100°C)
• Non flammable
• Odourless or has a slight smell of ammonia
• Delivered as colourless, aqueous solution
• ISO 22241 standard defines the purity and material requirements
Vehicles typically use
32,5 wt-% urea due to
the lowest possible
freezing point (-11 °C)
Marine vessels typically
use 40 wt-% urea due to
lower tank capacity need
and adequate enough
freezing point (0°C)
35 © Wärtsilä Wärtsilä NOx Reducer
Exhaust gas equipment arrangement example
18 February 2014
• The NOR mixing duct and reactor are the
first components after the engine due to the
temperature requirement of the NOx
Reducer operation.
• NOR designed for high sulphur HFO is
compatible with SOx Scrubbers.
NOR reactor
Boiler
Silencer
Scrubber
NOR mixing duct
36 © Wärtsilä Wärtsilä NOx Reducer
Low Pressure SCR
18 February 2014
First Tier III SCR on 2-S RTFlex58T
Benefits with Wärtsilä NOR solution
• More than 500 Wärtsilä engines with SCR in operation or on order today
• Optimized and validated for Wärtsilä medium speed engines in terms of
reliability and size.
• Fuel flexibility, including high sulphur fuels
• Flexible and optimized size according to engine characteristics and NOx
reduction targets
• Sound attenuation features
• Ability to integrate and optimize engine + SCR (+boiler+silencer+scrubber)
• Pre-fabricated and tested modularity, built in redundancy
• One supplier, single point of responsibility
• Worldwide service network in 70 Countries
18 February 2014 39 © Wärtsilä Wärtsilä NOx Reducer
Thank You!
18 February 2014 Wärtsilä NOx Reducer 40 © Wärtsilä
51 / © Wärtsilä
WÄRTSILÄ MARINE CEMS
CONTINUOUS EMISSION MONITORING SYSTEM
Wärtsilä CEMS, Feb. 2014 41
51 / © Wärtsilä
What is continuous emission monitoring?
• Continuously measuring concentration of specific components in
the exhaust gas
– Typically NOX, CO and SO2 emissions.
– Normally requires specialized equipment.
– Selecting right equipment is critical for robustness.
• WHY?
– Verification of compliance with
emission limits
– Reporting for emission trading or
taxation schemes
– Process feedback for control purposes
– “Voluntary” monitoring
• Stakeholder reporting
• Green certificates
• Optimisation of operation
Wärtsilä CEMS, Feb. 2014 42
51 / © Wärtsilä
CEMS – Extractive systems
• Exhaust gas sample is taken from the exhaust gas stack with a sampling probe
• The sample is conveyed in heated sampling lines to a gas analyser via sample
conditioning
Sampling probe Heated
sampling
lines
Gas sampling
and analysis
Data acquisition
and handling system
Wärtsilä CEMS, Feb. 2014 43
51 / © Wärtsilä
Time-sharing principle
• Several stacks are monitored by the same analyser (CEMS)
• Gas intake and measurements are automatically controlled by the analyser /
PLC
• Cost optimised solution as less components are needed
• Suitable for multi-engine installations
• Applicability depending on the regulation
Note: Systems based on timesharing principle are considered continuous monitoring systems.
Wärtsilä CEMS, Feb. 2014 44
51 / © Wärtsilä
Measured components
• CO2
– Range: 0-15 %
• CO
• NO – Range: 0-2000 ppm
• NO2
– Range: 0-300 ppm
• H2O – Range: 0-35 %
– Required as measurement is done o a wet-basis
• O2 (optional)
– Range: 0-21 %
• SO2 (optional)
– Range: 0-2000 ppm
• CH4 (optional) All components are
measured with NDIR
technology except O2,
which uses paramagentic
sensor.
Wärtsilä CEMS, Feb. 2014 45
Thank You!
18 February 2014 Wärtsilä NOx Reducer 46 © Wärtsilä