slow steaming solutions

Slow Steaming Solutions for fuel consumption reduction

2013-05-17

QMD

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Background

1. Background

Duo to ever rising fuel oil prices, owners and

operators of larger-bore two-stroke low-speed

engines have been looking for different ways to

save on fuel expenses without having to

compromise on engine reliability and emissions.

Since the worldwide financial crisis developed in

the second half of 2008, low-load operation or slow

steaming has been the standard of the day for

many owners operating two-stroke engines. In the

early days of slow steaming, mainly container

vessel operators requested to operate at low load.

Today, also operators of tankers, bulkers, etc. are

beginning to operate continuously at low loads.

QMD

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Background

Slow steaming operation

Low-speed two-stroke crosshead diesel engines are normally operated in a load

range above 40% CMCR.

Todays increasing fuel costs require rather slow vessel service speeds resulting

in an continuous engine operation between 20% and 40% engine load.

When running the engine continuously at loads lower than Normal Load , it is

called Slow Steaming.

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Background

Low load operation disadvantage without any modification :

1. Low turbocharger efficiency.

2. Higher exhaust gas temperatures.

3. Continuous operation in the Very Low Load range may result in increased

cold corrosion due to low combustion chamber temperatures, increased deposit

formation, and general engine fouling.

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Slow Steaming _Running with T/C cut off

Service Letter ( SL) RT-139, Running of main

engines with turbocharger cut-off

To protect engine against excessive high load,

temperature and stress while T/C cut off

operation

Introduction of power limit guidance for

unlimited continuous operation with T/C cut- off

operation

Special attention to monitor performance

parameters if engine operate above guided limit

Emergency operation due to unexpected T/C

failure are not intended

Service Letter RT-139

WRTSIL 2-STROKE SERVICE EXPERIENCE Big Bore May 2013

All TC in operation (25%,45% & 50% load), 8 RT-flex96C

1 TC in Operation (25%,45% & 50% load), 8 RT-flex96C

Excessive high

P max with T/C

cut off operation

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Slow Steaming _Running with T/C cut off

Installations with Wrtsil slow steaming upgrade kit

Wrtsil SSUK service product has Automatic limitation function for power limit

- 90% of max allowed T/C speed

- 90% Scav. pressure from FAT

proper setting of alarm to be monitored

Installations with turbocharger cut- off not supplied by Wrtsil

- Reset manual fuel limiter setting on Speed control system

- Reset Speed set point

- Monitoring of Shaft power meter

- On-line power monitoring system ( i.e ICC/ ICM )

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Engine operation in the load range between 20% and 100% CMCR without any

additional restrictions.

Electronically-controlled turbocharger cut-off without compromising on engine

reliability.

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The Upgrade Kit Slow Steaming enables:

Operating the engine at lower load without operation of the auxiliary blower

Reduction the risk of turbocharger and economiser fouling

Significant reduction of specific fuel consumption

Additional fuel cost savings, on top of the savings due to low-load operation

QMD

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With fitting blind flanges between the turbocharger and

exhaust manifold. Continuous operation between

20%~ 50% (2 T/Cs), and 20% ~ 66% (3 T/Cs).

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Flap valve is closed because seal air is supplied from engine side through seal air pipe.

In the result, sealing air is supplied to the seal air passage in bearing pedestal without

leakage to scroll.

QMD

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Flap valve is opened because seal air is supplied from scroll. In the result, sealing air is

supplied to the seal air passage from scroll and seal air pipe.

015

CONFIRMATION TRIAL

Engine Type : QMD-Wartsila 6RT-flex82C

Data : Sept. 22, 2012

Place : QMD assembly shop

016

CONFIRMATION TRIAL

Engine performance and emission

confirmation


T/C Type : MET 66MA x 2 sets

Pmax at 100% CMCR : 159 bar

Pscav at 100% CMCR : 2.95 bar

T/C speed nmax : 14,300 r/min Remove expansion joint between

the turbocharger and exhaust

manifold and fit blind flanges.

Remove expansion joint between

the turbocharger air outlet and

diffusor, and fit blind flanges.

017

PERFORMANCE


Data : Sept. , 2012

Place : QMD

018

FUEL CONSUMPTION


Data : Sept. , 2012

Place : QMD

Annual fuel saving at 45% load operation

168

170

172

174

176

178

180

182

184

186

10% 15% 20% 25% 30% 35% 40% 45% 50%

FOCNormal

Fuel Consumption comparison

019

EMISSION

NOx measurement result

020

APPLICATION EXAMPLE

Vessel Information

Vessel Type : 3,100 TEU Container Carrier

Vessel Name : Niledutch Beijing


Classification : GL

QMD modified the main engine of vessel

Nileductch Beijing with blink flanges from

normal condition to slow steaming condition

according to the requirement of the ship

owner.

After No. 2 turbocharger cut off, main engine

show good performance during main engine

normal operation and fuel consumption meet

expected value.

021

APPLICATION EXAMPLE

Vessel Information

Vessel Type : 3,100 TEU Container Carrier

Vessel Name : Niledutch Beijing


Classification : GL

Date : 2013, 04

Normal voyage fuel consumption operation with slow steaming

022

THANK YOU FOR YOUR ATTENTION.

Qingdao Qiyao Wartsila MHI Linshan Marine Diesel Co., Ltd.

Add:501 Li Jiang East Road, Economic and Technological Development

Zone, Qingdao, China

Tel : 086-0532-86708080

Fax : 086-0532-86708080-788

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