man b&w stationary engines alternative fuels

MAN B&W Stationary EnginesAlternative Fuels

Contents

Abstract .......................................................................................................5

Business concept .........................................................................................5

Definition of alternative fuels..........................................................................5

Experience with alternative fuels....................................................................6

Fuel supply system .......................................................................................8

Other auxiliary systems .................................................................................8

Selection of cylinder lube oil ..........................................................................8

Emission control ...........................................................................................9

Status in 2015..............................................................................................9

Evaluation of alternative fuels ...................................................................... 10

Outlook ...................................................................................................... 10

MAN B&W Stationary Engines – Alternative Fuels 3


MAN B&W Stationary EnginesAlternative Fuels

Abstract

The demand for energy and technologi-

cal development is increasing world-

wide.

Ideas, proven by operational experi-

ence on reciprocating engines with the

highest possible efficiency level, are

subject to renewed interest.

This paper deals with the use of alter-

native fuels in MAN B&W two-stroke

low speed engines for stationary ap-

plication.

Business concept

The MAN B&W two-stroke engines for

marine and stationary application, see

Fig. 1, are developed and designed by

MAN Diesel & Turbo. The actual sale

and production takes place via licen-

sees placed worldwide, see Fig. 2.

The MAN B&W two-stroke stationary

engines are applied for base-load op-

eration, peak-load operation, power

barges, direct drive of machines with

low rpm, or as part of energy storage

solutions. Both MAN Diesel & Turbo

and the licensees are available for tech-

nical clarification in connection with the

application of MAN B&W two-stroke

engines.

Definition of alternative fuels

Alternative fuels cover a wide range of

liquid fuels created by the processing of

different types of feedstock into liquid

fuels that can be applied to the energy

supply to electrical grids.

This technical paper focuses on alter-

native fuels that can be injected into

reciprocating internal combustion en-

gines of the MAN B&W engine design.

Liquid fuels may originate from the pro-

cessing of vegetables and plants, ani-

mal fats, used cooking oils and waste

products, resulting in pyrolysis oil.

In 1995, the general perception that

conventional fossil fuels were unlimited

was challenged by estimations predict-

ing that fossil fuel in liquid form was

limited. Consequently, new ideas have

emerged in the search for alternative

utilisation of liquid substances which,

potentially, can be fired into recipro-

cating internal combustion engines to

3,605 kW 79,520 kW

Fig. 1: MAN B&W two-stroke low speed engine programme

Fig. 2: Licensees for MAN B&W engines

CroatiaUljanik 1954Split 1967

KoreaHyundai 1976Doosan 1983STX 1984

ChinaHHM 1980DMD 1980YMD 1989CMD 2007STX 2007JAD 2007CMP 2008ZHD 2008RPM 2008YungPu 2008GMD 2011QMD 2014

PolandCegielski 1959Japan

Mitsui 1926 Makita 1981 Diesel United 2008Hitachi incl. IMEX 1951Kawasaki incl. Hanshin 1911

VietnamVinashin 2004

MAN B&W Stationary Engines – Alternative Fuels6

provide the highest possible efficiency

and secure the power supply in a world

with scarce resources. This is why we

choose to apply the designation alter-

native fuels.

Alternative fuels from vegetables cover

crude rapeseed oil, crude sunflower oil

and crude soya oil.

Alternative fuels from plants cover

crude palm oil and crude jatropha oil.

Alternative fuels with the designation

animal fats covers fats produced by the

processing of any type of meat in the

meat processing industry.


used cooking oil covers both vegetable

and animal-based products that have

already been applied in cooking pro-

cesses either in private homes or, more

likely, at restaurants.


“pyrolysis oil” are derived from the pro-

cessing of waste products according

Fig. 3: Components in direct contact with alternative fuel on MC-S engines. A: fuel pump. B: fuel valve.

to the pyrolysis process. Feedstock for

this fuel type may vary from used tires

to wasted or unconsumed food.


tall oil is a waste product from the pa-

per processing industry.

Common for these fuels are that the

lower calorific value is low compared

with those of fossil fuels. Average is ap-

proximately 36 MJ/kg.

Experience with alternative fuels

In 2001, the first experience with the

combustion of alternative fuel was

A

B

Table 1: Biofuel comparison sorted by TAN value

Biofuel Composition

Test Unit 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Acid number (TAN) mg KOH/g 0.57 4.15 4.72 6.40 6.70 7.20 7.60 7.85 9.40 11.17 11.20 14.00 17.00 24.96 40.5 42.00 48.30 52.40 59.80 83.50 133.00 154.50

Carbon residue % wt 0.14 0.34 0.36 0.56 0.19 0.42 0.00 0.52 0.50 2.00 0.74 1.5 0.43 2.20 9.30 16.40 15.30 28.20

Water by distillation % vol 0.11 0.50 <1 0.10 0.40 0.00 0.10 <0.05 22.00 6.50 26.00 17.80

Flash point °C 190 99 214 206 200 182 192 196 198 >230 239 200 >60 150 >200 > 200 206 68 >99 46 > 94

Phosphorous mg/kg 32 8 3 26 30 5 22 4 96 4 15 100 26 20 121 69 21 12

Lower calorific value MJ/kg 37.17 37.02 37.14 36.88 36.84 36.84 36.78 36.92 36.91 36.94 36.90 36.00 38.00 35.50 36,810 37.05 36.37 37.95 22.75 23.86 15.48 23.43

Density at 15°C g/ml 0.9217 0.9138 0.9235 0.9194 0.9184 0.9140 0.9198 0.9209 0.9192 0.9216 0.8888 0.9300 0.9050 0.9142 0.9165 0.9173 0.9271 0.9872 0.9710 1.1200

Viscosity at 50°C cSt 24.89 29.15 27.47 25.42 26.47 29.55 27.14 25.84 24.95 28.75 28.30 32.00 40.00 28.00 29.65 27.15 30.18 659.00 35.71 268.20 39.02 394.70

Sulphur ppm 4.3 1 10 <50 0.031

Ash % wt 0.027 0.006 0.006 0.015 0.016 0.017 0.014 0.005 0.001 0.002 <0.01 0.010 <0.1 0.005 0.039 0.019 0.054 0.130 0.092 0.010 0.098 0.040


Guiding Biofuel Specification 1)

Designation

Density at 15°C kg/m3 1010

Kinematic viscosity at 100°C 2) cSt 55

Flash point ºC >_ 60

Carbon residue % (m/m) 22

Ash % (m/m) 0.15

Water % (m/m) 1.0

Sulphur 3) % (m/m) 5.0

Vanadium ppm (m/m) 600

Aluminium + silicon mg/kg 80

Sodium plus potassium ppm (m/m) 200

Calcium ppm (m/m) 200

Lead ppm (m/m) 10

TAN (total acid number) mg KOH/g 4) < 25

SAN (strong acid number) mg KOH/g 0

1) Maximum values valid at inlet to centrifuge plant2) Pre-heating down to 15 cSt at engine inlet flange is to be ensured3) Lodine, phosphorus and sulphur content according to agreement with emission controls maker4) TBO of engine fuel systems to be adjusted according to actual value and experience

made with medium speed engines, and

MAN Diesel & Turbo’s office in Copen-

hagen, responsible for research, devel-

opment and design of MAN B&W two-

stroke low speed engines, was first

approached in 2005. It was acknowl-

edged that challenges for handling al-

ternative fuels with high total acid num-

ber (TAN) were to be expected in the

fuel supply system and in the fuel-injec-

tion equipment on the engine proper.

Table 1 shows that fuel characteristics

vary from fuel type to fuel type. It was

therefore evaluated that a new material

selection would be relevant especially

in the fuel injection system, as the con-

tent of TAN was expected to lead to

corrosion of any component in direct

contact with the alternative fuel, ref.

Fig. 3.

MAN Diesel & Turbo decided to test the

alternative fuel in the category tallow

with a TAN of 40. In 2006, at the Diesel

Research Centre in Copenhagen, a test

was conducted on one cylinder on the

research engine with standard mate-

rial for all engine components directly

in contact with the alternative fuel. The

test confirmed the expectations of the

necessity of changing the material se-

lection as well as the sizing of the fuel

injection equipment due to the calorific

value of the alternative fuel.

Table 2 shows the guiding biofuel speci-

fications. This guiding biofuel specifica-

Biofuel Composition

Test Unit 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Acid number (TAN) mg KOH/g 0.57 4.15 4.72 6.40 6.70 7.20 7.60 7.85 9.40 11.17 11.20 14.00 17.00 24.96 40.5 42.00 48.30 52.40 59.80 83.50 133.00 154.50

Carbon residue % wt 0.14 0.34 0.36 0.56 0.19 0.42 0.00 0.52 0.50 2.00 0.74 1.5 0.43 2.20 9.30 16.40 15.30 28.20

Water by distillation % vol 0.11 0.50 <1 0.10 0.40 0.00 0.10 <0.05 22.00 6.50 26.00 17.80

Flash point °C 190 99 214 206 200 182 192 196 198 >230 239 200 >60 150 >200 > 200 206 68 >99 46 > 94

Phosphorous mg/kg 32 8 3 26 30 5 22 4 96 4 15 100 26 20 121 69 21 12

Lower calorific value MJ/kg 37.17 37.02 37.14 36.88 36.84 36.84 36.78 36.92 36.91 36.94 36.90 36.00 38.00 35.50 36,810 37.05 36.37 37.95 22.75 23.86 15.48 23.43

Density at 15°C g/ml 0.9217 0.9138 0.9235 0.9194 0.9184 0.9140 0.9198 0.9209 0.9192 0.9216 0.8888 0.9300 0.9050 0.9142 0.9165 0.9173 0.9271 0.9872 0.9710 1.1200

Viscosity at 50°C cSt 24.89 29.15 27.47 25.42 26.47 29.55 27.14 25.84 24.95 28.75 28.30 32.00 40.00 28.00 29.65 27.15 30.18 659.00 35.71 268.20 39.02 394.70

Sulphur ppm 4.3 1 10 <50 0.031

Ash % wt 0.027 0.006 0.006 0.015 0.016 0.017 0.014 0.005 0.001 0.002 <0.01 0.010 <0.1 0.005 0.039 0.019 0.054 0.130 0.092 0.010 0.098 0.040

Table 2: Guiding biofuel specification

TAN limit of 25


Fig. 4: Fuel oil plunger at 5,855 running hours

tion enables clients to operate on crude

biofuel. This meant that for MAN B&W

two-stroke low speed engines there

was no need to install a special treat-

ment or cleaning system for biofuel

before the fuel enters the conventional

centrifugal system. Biofuels typically

have a low sulphur content – but as the

sulphur content does not influence the

fuel combustion, it was decided to allow

the high sulphur content in case alter-

native fuels with a high sulphur content

would eventually become available.

In 2007, the Polish licensee H. Ce-

gielski – Poznan S.A. got an order for

a 7L35MC-S engine to be installed in

Germany for operation on crude palm

oil. MAN Diesel & Turbo had agreed to

follow this installation closely to monitor

the condition of the engine components

in direct contact with the crude biofuel.

The components were inspected after

6,000 operating hours, and the condi-

tion of the fuel plunger is shown in Fig.

4. The parts from the fuel pump were

examined by detailed measuring equip-

ment, and the conclusion was that

the slight colouring of the surface was

cosmetic. No change of the surface

could be measured. The engine contin-

ued operation up to 10,000 operating

hours, after which the client decided

to stop operating on crude biofuel be-

cause a stable crude biofuel price could

not be ensured.

In 2008 the H. Cegielski – Poznan S.A.

secured the next order for a 7K60MC-

S engine to be installed in the UK for

operation on a wide range of bioliquids.

During the project, the client wished to

utilise the wide TAN range accepted by

MAN Diesel & Turbo, and the client also

decided to include fats, oils and grease

(FOG) in the fuel supply chain, which in-

cludes various types of animal fats and

recycled cooking oils.

Fuel supply system

A high TAN number is also to be con-

sidered for the design of the fuel supply

system, as the material selected must

prevent corrosion of fuel pipes and

fuel treatment systems. MAN Diesel &

Turbo recommends the application of

stainless steel or other corrosion resist-

ant material for both the pipes and the

fuel treatment system. The operating

experience from the fuel supply sys-

tem on the installation in Germany was

positive. Accordingly, we continue to

recommend this material selection for

the fuel supply system.

The fuel oil treatment system is shown

in Fig. 5.

It is important that the fuel treatment

makers receive a copy of the complete

biofuel specification and, even better

yet, a copy of the chemical analysis of

the biofuel.

The fuel treatment system components

are well-known in the marine industry.

Other auxiliary systems

As regards other auxiliary system com-

ponents, which are not in direct contact

with the biofuel, they may be designed

as per the standard guidelines for liquid

fuel handling systems.

Selection of cylinder lube oil

During operation on biofuel on the first

engine, it was observed that the choice

of cylinder lube oil and the application

of the lowest possible feed rate had

to be adapted to the ultra-low sulphur

content of the fuel injected. The forma-

tion of CaCO3 in the combustion cham-

ber is expected to be at a higher level

if the cylinder lube oil is not adapted.

Accordingly, the cylinder lube oil feed

rate must be lowered compared with

operation on high-sulphur liquid fuels.

2 mm


The power plant in Germany is there-

fore a good starting point for today’s fo-

cus on the reduction of SOx emissions,

where the marine market is moving in

the direction towards applying ultra-low

sulphur fuels, both in liquid form and in

gaseous form.

It is also worth noting that a cement

mill installation in Germany, with a di-

rectly coupled 4L35MC-S engine, has

been operating on ultra-low sulphur

fuel complying with the standard for

furnace oil for home appliances since

2007 without any technical problems.

In any case, it is important that the cyl-

inder lube oil maker selected receives

all information about the composition of

the alternative fuel.

Emission control

Relevant emission control equipment

is selected on the basis of the site re-

quirements for NOx, SOx and particu-

late matter (PM). For alternative fuels,

the very low sulphur content, which is

unaffected by the combustion process,

allows installation of SCR after the tur-

bocharger. Low-pressure SCR is there-

fore to be applied. For control of PM

emissions, it is suggested to apply an

electrostatic precipitator and monitor

the market for new emerging technolo-

gies for collection of PM.

Status in 2015

Operation of the MAN B&W 7K60MC-S

engine has started, and we have seen

varying TAN from the very beginning of

the operation, ranging from 1 to 25. The

calorific value varies around 36 kJ/kg.

The engine parts are in good condition,

and the mechanical operation follows

our expectations. This power plant has

been designed and constructed ac-

cording to the latest standards in order

to comply with the vision of the client

and the local legislation at site.

Heated pipe with insulation.

F

X

Heater

Option OptionTITIPIPI

Overflow back to storage tank

AF

Fuel oilsdrain tank

BD

To sludge tank Fuel oil

filter

Fuel oilmeter

Viscorator Circulating pumps

Start upservice

tank

Supply pumps

Aut. de-aerating valve

From centrifuges

Ventingbox

Biofuel service tank

To fresh water coolingpump suction

To biofuel service or settling tank

All fuel pipes and tanks to be made from stainless steel or other corrosion resistant material

Engine

Fig. 5: Fuel oil system, one engine


Evaluation of alternative fuels

MAN Diesel & Turbo always welcomes

questions about application of alter-

native fuels, and each request is ad-

dressed systematically step-by-step as

outlined in the following:

1. Clarification about the feedstock ap-

plied.

2. Explanation of the production pro-

cess.

3. The amount of the alternative fuel

available in the world market.

4. Expected fuel price when large scale

production is in place.

Items 1-4 provide information and a ba-

sic understanding. It is acknowledged

that what is at the initial stage today

may give new prospects tomorrow –

but it is always good to have a strategy

that is shared by all related parties.

5. One-litre sample (minimum) to be

sent to MAN Diesel & Turbo for

chemical analysis.

6. One-litre sample (minimum) to be

sent to MAN Diesel & Turbo for sta-

bility analysis.

7. Pump rig test without combustion at

the Diesel Research Centre in Co-

penhagen.

8. Combustion test for minimum 20

hours on one cylinder at the Diesel

Research Centre in Copenhagen.

9. Service test for minimum 4,000

hours.

The basic understanding of items 7-9 is

that the each step is commenced when

MAN Diesel & Turbo sees a possibility

of realising a positive outcome and, of

course, the steps 5-9 are subject to a

non-exclusive commercial and confi-

dential agreement.

With a positive outcome of step 9, it will

be possible for MAN Diesel & Turbo to

issue a no objection letter for the alter-

native fuel with a given specification.

Changes of the alternative fuel compo-

sition is to be reviewed and commented

by MAN Diesel & Turbo in each case, as

some of the steps may have to be re-

peated in order to clarify expected chal-

lenges relevant for the engine design.

Outlook

Fuel flexibility is important for MAN Diesel & Turbo as this can contribute posi-

tively to the diversity in the energy supply together with the unrivalled efficiency

of the MAN B&W two-stroke engine in a single cycle. Clients deserve the right

to select new possibilities that may become available as a result of the con-

stant technological development in any technical field. There is a first time for

everything, and we are ready to explore the combustion of alternative fuels in

reciprocating internal combustion engines of our design already at the early

stage of production.

Reference

Stationary MAN B&W MC-S Engine

For Biofuel Applications

5510-0098-00ppr

MAN Diesel & Turbo, Copenhagen,

Denmark, September 2010

MAN Diesel & TurboTeglholmsgade 412450 Copenhagen SV, DenmarkPhone +45 33 85 11 00Fax +45 33 85 10 [email protected]

MAN Diesel & Turbo – a member of the MAN Group

All data provided in this document is non-binding. This data serves informational purposes only and is especially not guaranteed in any way. Depending on the subsequent specific individual projects, the relevant data may be subject to changes and will be assessed and determined individually for each project. This will depend on the particular characteristics of each individual project, especially specific site and operational conditions. Copyright © MAN Diesel & Turbo. 5510-0177-00ppr Nov 2015 Printed in Denmark

man b&w stationary engines alternative fuels

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