Clean Marine AS
Version
PRE
Reg. no. NO 990 237 689 MVA
Status
Issued for Information
Issue date
2012-03-15
Made by
PMA
www.cleanmarine.no
Checked by
TN
Approved by
NHP
PROCESS DESCRIPTION
EXHAUST GAS CLEANING SYSTEM (EGCS)
DEVELOPED BY
CLEAN MARINE A/S
T HIS DOCUMENT CONTAINS CLEAN M ARINE LEGAL ENTITY PROPRIETARY AND CONFIDENTIAL INFORMATION THAT IS LEGALLY PRIVILEGED AND IS
INTENDED ONLY FOR THE PERSON OR ENTITY TO WHICH IT IS ADDRESSED AN D ANY UNAUTHORIZED USE IS STRICTLY PROHIBITED. IT IS PROVIDED
FOR LIMITED PURPOSE AND SHALL NOT BE REPRODUCED, STORED ELECTRONICALLY , TRANSFERRED TO OTHER DOCUMENTS, DISSEMINATED OR
DISCLOSED TO ANY THIRD PARTIES WITHOUT THE PRIOR WRITTEN CONSENT OF THE RELEVANT C LEAN M ARINE LEGAL ENTITY . A NY ATTACHMENTS ARE
SUBJECT TO THE SPECIFIC RESTRICTIONS AND CONFIDENTIALITY REGULATIONS STATED THEREIN AND SHALL BE TREATED ACCORDINGLY . T HE
DOCUMENT IS TO BE RETURNED UPON REQUEST AND IN ALL EVENTS UPON COMPLETION OF USE FOR WHICH IT WAS PROVIDED .
Process description
Exhaust Gas Cleaning System
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TABLE OF CONTENTS
1.
INTRODUCTION ..................................................................................................................................................... 4
2.
ABBREVIATIONS ................................................................................................................................................... 4
3.
HEALTH, SAFETY AND ENVIRONMENT .............................................................................................................. 5
4.
5.
6.
3.1.
Health ................................................................................................................................ 5
3.2.
Safety ................................................................................................................................ 5
3.3.
Environment ....................................................................................................................... 5
TECHNICAL DESCRIPTION................................................................................................................................... 6
4.1.
Working principle – exhaust gas and liquid interface ........................................................... 6
4.2.
Chemistry principle – sulphur trapping ................................................................................ 7
4.3.
Effluent water – monitoring and treatment........................................................................... 7
DESCRIPTION OF MAIN COMPONENTS ............................................................................................................ 8
5.1.
Exhaust inlet section .......................................................................................................... 8
5.2.
Coaxial pipe ....................................................................................................................... 8
5.3.
BDR ................................................................................................................................... 8
5.4.
Fans................................................................................................................................... 9
5.5.
AVC ................................................................................................................................... 9
5.6.
Nozzle assembly ................................................................................................................ 9
5.7.
Water supply pumps........................................................................................................... 9
5.8.
Water supply and overboard connections ........................................................................... 9
5.9.
Recycling pump.................................................................................................................. 9
5.10.
Cooler ................................................................................................................................ 9
5.11.
High pressure pumps ......................................................................................................... 9
5.12.
NaOH dosage pumps ....................................................................................................... 10
5.13.
System Tank .................................................................................................................... 10
5.14.
WTU tank ......................................................................................................................... 10
5.15.
WTU ................................................................................................................................ 10
5.16.
Sludge tank or WATU unit ................................................................................................ 10
5.17.
Holding Tank .................................................................................................................... 10
5.18.
NaOH Tank ...................................................................................................................... 10
5.19.
Distribution and control cabinets ....................................................................................... 10
5.20.
Variable Frequency Drives VFDs ...................................................................................... 11
5.21.
Monitoring system ............................................................................................................ 11
5.22.
Supporting structures ....................................................................................................... 12
5.23.
Piping............................................................................................................................... 12
5.24.
Cabling............................................................................................................................. 12
SYSTEM OVERVIEW and OPERATION............................................................................................................. 13
6.1.
Introduction ...................................................................................................................... 13
6.2.
Modes of Operation .......................................................................................................... 13
Process description
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6.3.
System capacity regulation ............................................................................................... 13
6.4.
Monitoring and Control ..................................................................................................... 14
6.5.
Start-Up and Operational Procedure ................................................................................. 14
Process description
Exhaust Gas Cleaning System
1.
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INTRODUCTION
The purpose of this document is to describe and explain the process of the Exhaust Gas Cleaning
System (EGCS) developed by Clean Marine A/S.
The EGCS system is designed to reduce Sulphur Dioxide, SO2, in the exhaust gas emitted from
marine machinery prior to atmospheric release through the funnel. The SO2 is removed by way of
absorption by NaOH and seawater.
The description needs to be read together with the Process & Instrument Diagram (P&ID).
PLC configuration and operator screen layout/functionality is not part of this document and as such
not covered.
2.
ABBREVIATIONS
AVC
Advanced Vortex Chamber
BDR
Gas Bypass, Droplet catcher and Re-circulation device
CM
Clean Marine as
CO2
Carbon dioxide
EGCS
Exhaust Gas Cleaning System
EGC unit
Exhaust Gas Cleaning (gas/liquid interface) unit
FTU
Measurement unit for turbidity
GPS
Global positioning system
IMO
International maritime organization
NaOH
Sodium hydroxide (or Caustic soda)
NOx
Nitrogen oxide
PAH
Polycyclic Aromatic Hydrocarbons
pH
Measurement of acidity or alkalinity of a solution
PLC
Programmable Logic Controller
PM
Particulate Matters
RPM
Revolutions Per Minute
SOx
Sulfur Oxide
VFD
Variable Frequency Drive
WTU
Water Treatment Unit
WATU
Water After Treatment Unit
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3. HEALTH, SAFETY AND ENVIRONMENT
3.1.
Health
50% NaOH (Caustic soda) solution is used to boost the cleaning process and/or to compensate for
fluctuating content of base material in ambient cleaning water. NaOH is corrosive and toxic and can
cause blindness, chemical burns, or scarring in contact with unprotected eyes or tissue. There should
be no direct contact between NaOH-solution and any parts of the body. NaOH must not be ingested
and its vapors should not be inhaled.
If NaOH-solution has been in contact with eyes or skin, the exposed area should be washed with
large amounts of water for minimum 15 minutes and wet clothes should be removed immediately, to
prevent damages due to etching and burns.
3.2.
Safety
All personnel must wear personal protective equipment, such as safety shoes, gloves, protective
goggles and hardhat (if required) when work is performed on any part of the Exhaust gas cleaning
system. When handling NaOH-solution, rubber gloves, safety clothing and safety goggles must be
worn.
Personnel working in height must wear proper safety harness and be secured to a fixed point at all
times. All major maintenance operations should be performed when in port and a proper scaffolding
should be installed to prevent falling objects and to secure personnel.
NaOH-solution shall not be exposed to aluminum at any point due to the production of hydrogen gas
in the reaction between sodium hydroxide and aluminum.
2Al(s) + 6 NaOH(aq)  3 H2(g) + 2 Na3AlO3(aq)
3.3.
Environment
The EGCS is designed to capture SO2 as sulfate in an interacting liquid. In this cleaning process also
waste products such as soot and ash particles are contained in the cleaning liquid. The level of
contaminants is monitored according to the IMO Guidelines and if exceeded, water cleaning is
initiated. This may produce sludge which will be collected onboard for disposal ashore.
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4. TECHNICAL DESCRIPTION
4.1.
Working principle – exhaust gas and liquid interface
The EGCS include an integrated multi stream gas/liquid interface unit – the EGC unit – consisting of
exhaust inlets, two fans, a cyclone and an exhaust piping system allowing part of the exhaust
automatically to be re-circulated through the unit as the exhaust production varies (i.e. when the
engine loads varies). This particular feature, allows all exhaust emitting sources to be connected to
one gas/liquid interface unit without affecting the backpressure in respective exhaust lines. Thereby,
the system works totally independent of engine loads and allowable backpressure produced by turbo
chargers or scavenging fans.
The raw exhaust gases from one or more sources are collected via separate inlets at the top of the
EGC unit. From the inlet collection point, the gas passes through exhaust inlet pipes consisting of one
common pipe (the outer ring of a co-axial pipe) and two branch pipes by two fans. The gas is ejected
into an Advanced Vortex Chamber (AVC) by two fans before being discharged to air, or recycled back
through the system.
Clean exhaust pipe
Main engine exhaust inlet
Aux. engine and boiler inlets
NaOH and pre-injection nozzles
Co-axial pipe
EGCS Fans
Water injection
Advance Vortex Cyclone
Effluent water outlets
outlets
The gas streaming through the system, being either raw or recycled gas, is exposed to two
subsequent interface processes with water at two different locations:
1. NaOH 50% solution and sea water is sprayed into the gas stream via separate nozzles
strategically located in the exhaust inlet pipes of the gas/liquid interface unit (pre-injection). The
nozzles as well as the subsequent fans ensure that the liquid is well mixed with the gas stream
2. Before the cyclone at the inlet to the AVC, the main bulk of liquid, being seawater or fresh water
pending operation mode, is injected. The gas and liquid mixture is provided both by the nozzles
and the cyclone created inside the AVC
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Being a retrofit or a new build installation, the exhaust from all sources connected to the system is
drawn through the pre-injection phase by two fans and injected into the second phase in the AVC.
The fans are dimensioned to take the highest relevant accumulated engine loads such as propulsion
engines, auxiliary engines and boilers.
Unless the accumulated load is very low, the fan speed will be kept constant.
When the fan speed and water flow has been set, the regulation of sulfur in exhaust gas is governed
by the NaOH addition versus the SO2 / CO2 -relation measured at the clean exhaust gas outlet.
4.2.
Chemistry principle – sulphur trapping
Water is the main dissolving and capturing liquid in the exhaust gas cleaning process. Commercial
available NaOH solutions (50%) are added to the process just after the water pre-injection point to
boost the SO2 or SO3 to sulfite (NaHSO3) or sulfate (NaHSO4) transformation process. This addition of
NaOH will also compensate for any fluctuating base content in the water and will also limit the amount
of sea-, brackish- or fresh water used. The NaOH addition is also used to regulate pH in effluent water
as required.
When dissolved in the liquid, SO2 originating from the burnt crude oil, will bind to base material
through an acidic transformation to harmless sulfites/sulfates.
SO2 + H2O  H2SO3 and/or SO3 + H2O  H2SO4
Na+ + OH- + H2SO3  Na+ + HSO3- + H2O
Na+ + OH- + H2SO4  Na+ + HSO4- + H2O
4.3.
and/or
Effluent water – monitoring and treatment
The cleaning liquid do also captures organic compounds, minerals and other species in the exhaust
gas. Polycyclic Aromatic Hydrocarbons (PAH) and turbidity levels of incoming and outgoing water are
monitored continuously and compared with permissible limits.
If the PAH and/or the turbidity level for any reason should exceed the permissible limits, water
cleaning will be initiated.
The EGC unit has two different effluent streams one from the two fan housings and one from the
bottom of the AVC. The former stream stems from the pre injection water and carries most of the soot
captured by the system. This stream is led to a Water Treatment Unit (WTU) tank and from this tank
either straight to the system tank (no cleaning) or via a back flush filter (cleaning) to the system tank
(cleaned water) and to either A) a sludge tank or B) a Water After Treatment Unit (WATU) (the
contaminated water).
A) The contaminated back flush water is contained in a sludge tank until discharged to shore.
B) The contaminated back flush water is filtered through a bag filter where the filtered water goes to
the system tank while the loaded bag filter is landed for disposal.
Process description
Exhaust Gas Cleaning System
5.
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DESCRIPTION OF MAIN COMPONENTS
An EGCS consists of the following main components:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
5.1.
Exhaust inlet section (1 off) – part of EGC unit
Coaxial pipe (1 off) – part of EGC unit
BDR (1 off) – part of EGC unit
Fans (2 off) – part of EGC unit
AVC (1 off) – part of EGC unit
Nozzle assembly – (1 off) – part of EGC unit
Water supply pump (2 off)
Water supply and overboard connections (1 off)
Recycling pump (1 off) – if closed loop operation
Cooler (1 off) – if closed loop operation
High pressure pumps (2 off)
NaOH dosage pumps (2 off)
System tank (1 off)
WTU Tank (1 off)
WTU (1 off)
Sludge tank or WATU unit (1 off)
Holding tank (1 off) – if closed loop operation
NaOH tank (1 off)
Switch and distribution board (1 off)
Monitoring system (1 off)
Supporting structures (1 set)
Piping (1 set)
Wiring (1 set)
Exhaust inlet section
Each exhaust source has a separate inlet channel that meets at a common gas meeting point before
the water pre injection nozzles. Each inlet channel is designed to take the full exhaust load from the
source. The exhaust inlet section is connected to the outer section of the coaxial pipe.
5.2.
Coaxial pipe
The coaxial pipe has an outer pipe (raw exhaust pipe) connected to the exhaust inlet section and to
the two branch pipes leading to the fans, and an inner pipe (clean exhaust pipe) running from the
AVC to the clean exhaust outlet. A section of the clean exhaust pipe will have slots (BDR) to allow
gas to pass from inlet pipe to outlet pipe and vice versa. The gas passing through the BDR from outlet
pipe to inlet pipe when exhaust loads are less than the fan capacities, meets at the common gas
meeting point. Water and NaOH 50% solution are strategically injected into the gas stream just after
the gas meeting point.
5.3.
BDR
A combined Bypass, Droplet catcher and Recirculation feature (BDR) is incorporated in the EGC unit.
The BDR fulfills three functions:
1. In case of fan failures, the exhaust gas will automatically escape through the EGC unit and the
openings in the BDR device and thereby ensure that the machinery integrity is intact.
2. The exhaust gas will move through the inlet pipe in a spiral and droplets will separate and escape
through the slots in the BDR.
3. The exhaust gas production is less than the fan capacity and more or less exhaust gas will be
recirculated through the BDR slots as engine loads change.
Process description
Exhaust Gas Cleaning System
5.4.
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Fans
The EGC unit is equipped with two (2 x 60%) fans with VFD at the AVC inlet. The raw exhaust gases
from one or more sources and any recycled clean gas meets and passes through the outer section of
the coaxial pipe and the two branch pipes leading to the fans. The gas is injected into an Advanced
Vortex Chamber (AVC) by the fans before being discharged to air or recycled back through the
system.
The fans together with the automatic re-cycling (BDR) excess clean gas allows all exhaust emitting
sources to be connected to one EGC unit without affecting the backpressure in respective exhaust
lines, and hence the efficiency of the emitting sources.
5.5.
AVC
The AVC is an advanced cyclone where gas and liquid interacts and separates at high speed. The
exhaust gas enters the AVC inlet chamber and is mixed with water sprayed into the gas stream
before the gas and liquid mixture is forced into a vortex in the AVC cone. Water is subsequently
separated from the gas stream and is collected in the AVC bottom sump, from where it is drained by
gravity flow through a pipe to the sea or to a holding tank via a system tank.
The outlet of the AVC is connected to the inner coaxial clean exhaust pipe.
5.6.
Nozzle assembly
Liquids are injected at two locations – at the upper part of the coaxial pipe as pre injection water and
NaOH 50% solution dosage, and at the AVC inlet chamber. The nozzle assembly consist of three
types of nozzles serving the liquid injection purpose. The water nozzle pressures are:
 Pre injection – about 10 bar
 AVC inlet chamber – about 1,5 bar
5.7.
Water supply pumps
Two (100% redundant) water supply pumps with VFDs draw ambient water from dedicated or
common sea chests. In open loop mode the pumps deliver water to the AVC inlet chamber nozzles
and the high pressure pre injection pumps. In closed loop mode the pumps deliver water to the
recirculation cooler.
5.8.
Water supply and overboard connections
Ambien water may be taken from existing common sea chest or separate sea chests may be
arranged with strainers. The ambient water is filtered to avoid subsequent clogging of nozzles.
Effluent sulphate/sulphite rich water is eventually discharge back to sea through dedicated discharge
connections.
5.9.
Recycling pump
In case of closed loop operation, a water recycling pump with VFD is provided. This pump will draw
water from system tank and supply same to AVC inlet chamber nozzles and high pressure pre
injection pumps.
5.10.
Cooler
In case of closed loop operation, a cooler shall be installed to maintain the temperature in the
recirculated water. Cooling water will be supplied by the water supply pump.
5.11.
High pressure pumps
Two (100% redundant) high pressure pumps with VFDs provide the water to the pre injection
nozzles.
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5.12.
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NaOH dosage pumps
Two (100% redundant) NaOH dosage pumps will supply the NaOH 50% solutions to the dosage
nozzles.
5.13.
System Tank
Effluent water from the EGC unit will either go directly to the system tank or via WTU tank and
subsequent cleaning to the system tank. From the system tank the water will either be discharged
overboard (open loop operation) or go to the circulation pump (closed loop operation). The system
tank has a fresh water filling line for make up water and a water bleed to holding water tank (closed
loop operation).
5.14.
WTU tank
The EGC unit has two sources of effluent water:
 Pre injected water is tapped from the fan housings.
 Water is collected and discharged from the bottom of the AVC cone.
The former source carries most contaminants and is the focus of any water cleaning. Said water is led
to the Water Treatment Unit (WTU) tank and if cleaning is required the water is filtered through the
WTU. If cleaning is not required, the water flows to the system tank.
5.15.
WTU
The WTU is a back flush filter. Effluent water is fed by gravity (10 mwc) or via separate pump from the
WTU tank to the WTU unit. Filtered water is fed from WTU unit to the system tank and flushed water
is led to sludge tank or the WATU unit (optional).
5.16.
Sludge tank or WATU unit
The back flush water is either collected in a sludge tank for subsequent discharge ashore, or the
water is led to a Water After Treatment Unit (WATU). The back flush water is then filtered through
the duplex bag filters of the WATU. The filtered water is led to the system tank while the loaded
filter bags when well drained are landed ashore.
5.17.
Holding Tank
In closed loop mode sulphate/sulphite saturated water is bled to a holding tank. From the holding tank
the water is discharged to sea or to shore. If discharged to sea, the water is first mixed with open loop
water before PAH and turbidity is measured.
5.18.
NaOH Tank
The NaOH tank shall be able to store NaOH 50% solution (1,5 mt/m3). If exposed to low temperature,
the tank shall have heating facilities. The tank shall have proper ventilation, drip trays and quick
closing valve. Eye wash shower and personal protective equipment shall be provided
5.19.
Distribution and control cabinets
A 440V distribution cabinet and a control cabinet shall be provided. The 440V cabinet is for 440V
distribution and 440V/230V transformer. Control cabinet contains PLC, all necessary I/Os, 24DC and
230V distribution.
Process description
Exhaust Gas Cleaning System
5.20.
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Variable Frequency Drives VFDs
The VFDs will either be grouped and located close to distribution and control cabinet, or locally close
to respective user.
5.21.
Monitoring system
The following parameters are monitored and recorded:







GPS – position signal
Turbidity PAH, temperature, pH of entering water and discharged water
Flow of NaOH and other liquids entering and leaving the system
CO2 and SO2 of cleaned gas
Gas temperature at manifold inlet and exhaust gas outlet
Gas pressure at inlet exhaust manifold, before the fans, after the fans and after the AVC
Level in NaOH tank and holding water tank
The data is stored in a central PLC and the following parameters are presented tamper free as
function of time and geographical position for compliance assessment and documentation:


SO2 / CO2 ratio and corresponding equivalent Sulfur content in fuel oil
PAH, turbidity, pH and temperature in liquid supplied to the system and discharged overboard and
the differences
The main controlling mechanisms of the system are:





SO2 [ppm]/CO2 [%] governing the NaOH dosage
The programmed load functions governing any capacity reduction of the EGC unit (see section
2.2.2). This in turn is linked to the frequency controls of the pumps and fans.
The switch in operation mode and activation of motor valves
The activation of bypass mechanism (dampers) in case of malfunctions
The startup of redundant equipment
The system has the following alarm functions:






Excessive gas pressure at exhaust gas meeting point
High SO2 [ppm]/CO2 [%]
Low liquid flow
High/low liquid pressure
Low level NaOH storage tank
High temp exhaust outlet
Exhaust by pass dampers are activated (opened) and pumps are stopped:




at high gas pressure at exhaust gas meeting point
if both fans stops
at high exhaust outlet temperature
at high pressure in AVC cone (liquid build up in system).
Process description
Exhaust Gas Cleaning System
5.22.
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Supporting structures
The EGC unit is supported below the AVC inlet cover and below the exhaust inlet section. The weight
is equally shared by the two supports.
5.23.
Piping material
The NaOH dosage system allows the pH of effluent water to be kept above 6,5 also in open loop
mode. This will allow use of heavy schedule mild steel piping both for supply and discharge piping.
GRE is a relevant alternative for water supply and discharge.
5.24.
Cabling
440V supply cabling shall be arranged from main switch board to 440V distribution cabinet and
control cabinet. From distribution and control cabinet 440V, 230V and 24V DC cabling shall be
arranged to VDFs and respective components.
Process description
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SYSTEM OVERVIEW AND OPERATION
6.1.
Introduction
This chapter covers the basic principles for the EGCS operation. PLC configuration and operator
screen layout/functionality is not part of this document and as such not covered. A full logic program
document will be issued for PLC program development.
The objective is to control the EGCS in a safe and proper manner. This includes:





To allow safe start up, synchronizing, running operation and shut down.
To maximize the availability.
To incorporate the maximum level of automatic control.
To minimize mechanical and thermal stresses in start-up and shut down.
To maximize SOx capturing efficiency at minimum consume of water, NaOH and power.
In normal operation the EGCS will be controlled from a designated control station being the engine or
cargo control room or the bridge. The PLC may well be interlinked with other control systems on
board. Local push buttons for maintenance activities will be provided on MV motors and integral
motorized valves.
6.2.
Modes of Operation
In normal operation all control is performed from operator screens. As a general rule each elementary
system is sequentially controlled from the operator workstation through automatic start-up / shutdown
sequences. Manual control of single equipment can be done also by local push buttons.
Being a hybrid system with the adding of base material NaOH 50% solution, the system may be
operated in several different modes. The two main operating modes are:
Open loop:
Ambient water being sea water, brackish water
or fresh water is used as main cleaning agent
and pass through the EGC unit once. NaOH
50% solution is dosed into the water stream to
achieve the desired SOx capturing level and pH
level.
If required due excessive PAH or turbidity
levels, effluent bleed streams from the fan
housings will be filtered through the WTU unit.
6.3.
Closed loop:
Water I circulated through the EGC unit, the
system tank, the circulation pump and the cooler
while NaOH 50% solution is added. As water is
saturated with sulphite/sulphate fresh water is
added while saturated water is bled to the holding
tank.
The effluent bleed streams from the fan housing is
collected in the WTU tank and filtered through the
WTU before reintroduced into the loop.
System capacity regulation
The EGCS is designed such that no interface with exhaust sources and their loads are required. When
the speed of the fans have been set the system can handle any exhaust amount equal or less the fan
capacity. The operator can choose to run the system at maximum capacity even at very low exhaust
loads or the capacity can be aligned with the requirements to reduce energy consumption.
The capacity of the system can then either be regulated by selecting a fan and water pump speeds as
per operational requirements (buttons for sea mode, port stay etc.) or by analogue adjustment of
capacity as required to maintain a neutral pressure level at the exhaust gas meeting point and.
Process description
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6.4.
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Monitoring and Control
The system is monitored and controlled by PLC. All signals from sensors will control water amount,
fan power and NaOH consumption. Fans and pumps in the system are run by VFD and every system
will be tuned for optimal performance during commissioning.
Environmental data from the system will be logged to tamper free storage unit together with GPS
signal for documentation purposes. Environmental data includes pH, turbidity and PAH level in water
and the SO2/CO2 ratio in the cleaned exhaust gas. All other parameters will also be logged as
historical data.
Human interface to the system will be screen mounted on a PLC cabinet with access to all
parameters. The screen will display a process picture. In addition, the system can be connected to
the ships LAN and will here be monitored via web browser and give access to all parameters. The
system can then be monitored from any computer in the ships LAN. In addition to this, the system
can be linked via satellite from Clean Marine office and remote service can be done.
6.5.
Start-Up and Operational Procedure
The operation procedure will be thoroughly described in the onboard maintenance manual included
with delivery. Typical start-up sequence and operation checklists are referred below for information.
Start-up sequence
Ensure all liquid in the system is prepared for start up
Start main pumps at low RPM
Start fans at low RPM and gradually increase RPM to design point
Start pre-injection pump
Increase main pump RPM to design point
Start WTU if required
Close permanent bypass hatch
Start NaOH pre-injection pump
Normal operation check-list
Frequency
Signs of any leaks
Daily
Signs of vibrations
Daily
Signs of excessive heat
Daily
NaOH storage level
Daily
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When shutting down the system, the reverse startup sequences are used.
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