What is Exhaust gas cleaning systems (EGCS)?

25 Sep, 15:10

Sept. 25, 2021, 3:10 p.m.
KnowledgeBase's gravatar image


Exhaust gas cleanings systems (ECGS) is an alternate means of compliance to MARPOL Reg. 14 of Annex VI. This regulation requires use of 0.5% Sulphur fuel worldwide and 0.1% Sulphur fuels in ECA from 1 January 2020.

SO2(ppm) / CO2 (%) ratio values in the exhaust emission is the basis for compliance.

ME, AE, Boilers and any other equipment using HSFO are normally connected to the EGCS. Use compliant low Sulphur fuel for any combustion equipment not connected to the EGCS.

Please note US State of California requires the use of 0.1% Sulphur distillates and does not permit the use of alternate facilities like EGCS.

EGC systems must comply with the IMO Scheme A or Scheme B requirements as below:

Scheme A    
Scheme B 
Initial CertificationEGCS Unit certification(SECC) issued after confirming the parameters and exhaust gas emission testEGCS Unit certification not required but continuous emission monitoring and parameter verification required on board. 
Onboard verification and continual complianceContinuous monitoring of EGCS operating parameters, daily checks of exhaust emissions and continual monitoring of washwater dischargeContinuous emission monitoring together with daily spot check of EGCS operating parameters and continual monitoring of washwater discharge

a) SECP (SOx emissions compliance plan)

b) SECC (SOx emission compliance certificate)

c) ETM- A (Technical Manual for Scheme A)

d) OMM (Onboard Monitoring Manual)

e) EGC Record Book or Electronic Logging system (operational and maintenance records)


b) ETM- B

c) OMM

d) EGC Record Book or Electronic Logging System

EGC systems (SOx scrubbers) fitted normally on ships are wet scrubbers - open, closed or hybrid types.


a) Uses untreated seawater (i.e. the natural alkalinity of SW) to neutralize the sulphur from exhaust gases. Monitor PH closely while using in FW areas (some ports/rivers).

b) Washwater processed and discharged overboard.

b) No purchase and handling of caustic soda and processing of wash water required.


a) Typically uses FW (rarely SW) treated with Caustic Soda (NaOH) to neutralize the wash water.

b) Most of washwater recirculated and a small bleed-off is treated for residual/ sludge removal for shore disposal. The treated water is either discharged overboard or stored in a holding tank for subsequent overboard discharge.

c) Allows use in ports/inland waters which prohibit EGCS discharge.

d) Scrubber works with same efficiency independent of where the ship is operating.


Allows operation in either open or close loop mode depending on area of ships operation and local regulations.

Utilizes the advantages of both open and closed loop system


Does not use water but exposes the exhaust gas to hydrate lime to remove SOx compounds.

Can be installed before the economizer or in conjunction with SCR units for NOx reduction

permanent link

25 Sep, 15:53

Sept. 25, 2021, 3:53 p.m.
cheng's gravatar image

add your answer

MarineProHelp 2018 - 2021