additive solutions for low sulphur fuelsadditive solutions for low sulphur fuels july 10
DESCRIPTION
HFO Sludge problemsTRANSCRIPT
Additive Solutions toOperational IssuesCaused by the Use ofLow Sulphur Fuel
Presentation by Ian CrutchleyTechnical Co-ordinator – Marine SpecialtiesInnospec Ltd
Agenda
Introduction
Stability of Heavy Fuel oil (HFO)
Compatibility of HFO / Marine Gas Oil (MGO)
Lubricity of MGO
Stability of MGO
Discussion
MARPOL Annex VI, Regulation 14 – Sulphur Limit Schedule
ECA = Emission Control AreaSource - IMO
Source – Falmouth Oil Services Ltd
EU Directive 2005/33/EC
“From January 1, 2010, under the Directive, themaximum allowable sulphur content of fuel oil usedby ships ‘at berth’ in EU ports, other than those inthe outermost regions, will be 0.10% by mass”.
“Exception: Certain named ships, and ships whichare timetabled to be at berth for less than twohours, will be exempt from the requirements”.
Stability and Compatibility ofHeavy Fuel Oil
Fuel tank sludge caused by unstable blend of HFO
How is Sludge Formed?
Sludge can be formed due to instability. Stability is the fuels’ability to resist change as a function of time and temperature.
Sludge is formed due to the agglomeration of asphalteneswithin residual fuels.
Sludge can be formed due to incompatibility. Compatibility isthe ability of the fuels to remain stable when blended.
Instability and incompatibility are associated with the resin toasphaltene ratio within the fuel. Fuels that have beensubjected to secondary refining processes tend to be moreunstable due to the low resin content.
HFO can be naturally unstable or become unstable onceblended.
Stability is assessed with Hot Filtration Test (HFT), P-Value orthe Turbiscan method.
Solution: Dispersant / Stabiliser additive
Function of a Stabiliser:
Simulate natural resins thathave been removed bysecondary refining whichkeep the asphaltenesemulsified.
Function of a Dispersant:
Re-emulsify the existingagglomerations - clean upeffect, make good fuelfrom sludge.
How to increase Stability?
Turbiscan Heavy Fuel – Measuring Principle
The Turbiscan testuses light scatteringto measure thephase separation ofthe oil and expressesstability in terms ofSeparability Number
Illustration of stability test – ASTM D 7061
0 min 1 min 2 min 3 min 4 min 5 min 6 min
Without additive
0 min 60 min
With Octamar™BT-8 Plus
What is blending and why do we do it?
Compose a product that is “fit – for – purpose” complying withthe agreed quality limits, usually with regard to Viscosity andDensity.
Make the product at “minimum cost”.
With new legislation on Sulphur limits, blending is set tobecome even more complex and abundant.
Potentially, blending of fuels can take place several timesbefore reaching the engine:
By refinery to meet ISO 8217 requirements.
By trader or supplier to meet customer requirements.
On board in fuel tanks, or during changeover.
HFO Day Tank95°C
MixingColumn
100% HFO
100% MGO
MGO Tank25°C
HFO & MGO Compatibility During Changeover
To Engine
Blending of HFO & MGO During ChangeoverTurbiscan test method – ASTM D7061-05
SN < 5: good stability reserve, pass5 < SN < 10: limited stability reserve, fuel oil may flocculateSN > 10: unstable fuel oil, likely flocculation of asphaltenes
TSP (total sediment potential) – IP390A/IP375 Max: 0.10
Separability Number
0.32
0.27
0.10
0.10
TSP
13.02
12.90
10.63
10.65
NoAdditive
60%HFO40%MGO
65%HFO35%MGO
70%HFO30%MGO
HFO
Sample
0.43
0.31
0.25
0.18
100ppm Octamar™BT-8 Plus
Additive Solutions to Instability & Incompatability
Stabilise vis-broken residues so that, when blendedwith cutter-stock or MGO, the asphaltenes will remainin suspension.
Remove existing asphaltene agglomerations by thedispersancy effect.
Field Trials have resulted in 50 – 60% sludgereduction.
Reduced cost for sludge disposal, reduced tankcleaning requirement, more homogenous fuel equalsbetter ignition and combustion, reduced workload onseparators, reduced PM emissions, extendedmaintenance schedules.
Untreatedasphaltenes
Treatedasphaltenes
Octamar™ BT fuel treatments for stability
Typical PropertiesAppearance clear, reddish-black liquidDensity ...............1010 kg/m3 at 15°CFlash point…….………….……> 61°C
Dosage Rate: 1 : 10,000
ApplicationA unique product for stability &combustion improvement in bunkerfuel driven marine diesel engines.
Typical PropertiesAppearance ……dark, brownish liquidDensity ................870 kg/m3 at 15°CFlash point…….…..….….……> 62°C
Dosage Rate: 1 : 10,000
ApplicationA unique product for stabilityimprovement & sludge reduction inbunker fuel driven marine dieselengines.
Octamar™ BT-25
Typical PropertiesAppearance …….…dark, brownish liquidDensity .......................930 kg/m3 at 15°CFlash point…….……………...……> 61°C
Dosage Rate: 1 : 25,000
ApplicationA unique product for sludge reduction,stability and combustion improvementsas well as fuel savings in bunker fueldriven marine diesel engines
Octamar™ BT-8
Lubricity of MGO
What is Lubricity?
Lubricity – “The intrinsic ability of afluid to prevent wear on contactingmetal surfaces”
What reduces lubricity in middle distillate fuels?
Hydroprocessing at the refinery to reduce sulphurlevels also removes
N species
O species
Polyaromatic
Others
High sulphur fuel has natural lubricity from theminor species
Remove the sulphur the lubricity is removed
Low Lubricity – Consequences and Solutions
Diesel lubricity problems manifested by:excessive wear of fuel injection equipment
Potential solutions:Increase sulphur levelsLess hydroprocessing - not possible for high sulphur crudesimproved pump metallurgy - increased cost to FIEmanufacturers and many old pumps already in the fielduse of lubricity additives - preferred choice
Requirements for additive use:acceptable method for measurement of lubricityperformance in real life pump situationslack of interaction with fuels, lubricants or other additives
Diesel Pump Lubricity – Pump Rig
Low sulphur fuelsintroduced in Sweden &California 1990-1
Effects on engines & FIEnot recognised
Failures reported in 1990-1of distributor/rotary injectionpumps
World-wide across allmanufacturers 65 millionpumps have been affected
Pumps rely on fuel aslubricant
Diesel Pump Rig Rating
E.O.T Pump Is Dismantled
Critical Wear Components Are Rated
Rating 1 - 3.5 = Pass , > 4 = Fail
Rating System Developed By Bosch
Rating Components
Lubricity Specifications
Lubricity test methodHigh Frequency Reciprocating Rig (HFRR) 60 °CMeasures wear scar diameter (WSD) in µm
HFRR - Europe, Japan, SEAStandard Bench test CEC F-06-96 / IP450 / ASTM D6079European Diesel fuel standard EN 590 states amaximum 460 µm specificationUS ASTM standard states a maximum 520 µmspecificationProposed version of ISO8217, due in July 2010,specifies fuels below 0.05% S must be tested. Max520µm.
Upperspecimen
Lower Specimen
HFRR / Pump Rig Correlation
Source: Robert Bosch GmbH Stuttgart
How does a lubricity additive work?
Lower Specimen
Lubricity Additive
Upper Specimen
Impact of low sulphur
Typical HFRR Performance – Good Additive Response
200250300350400450500550600
0 50 100 150 200 250
500ppm Sulphur 350ppm Sulphur50ppm Sulphur 10ppm Sulphur
Typical PropertiesAppearance ……………………….…Yellow liquidDensity ...................................910 kg/m3 at 15°CViscosity……………………..……..16 cSt at 40°CPour point……………………………………- 12°CFlash point…….………………...……...…> 100°C
Dosage Rate1 : 10,000
ApplicationA proven product for lubricity improvement ofmarine diesel fuel and marine gas oil
Octamar™ LI 5
Octamar™ LI 5 demonstrates the following at recommended treat rates :
restore the natural lubricity of distillate fuel oils that has been reduced inthe process of removing sulphur.
reduce wear of fuel pumps and fuel injection equipment when operatingwith fuels of low intrinsic lubricity.
performance in the stringent Bosch pump rig lubricity test
excellent response in the High Frequency Reciprocating Rig (HFRR)bench test
protection against corrosion
absence of interaction with engine lubricants
complete compatibility with engine materials and fuel system.
Conclusions
Summary
Laboratory tests have proven that not all fuels with < 0.05%sulphur will fail ISO 8217 limit of 520µm.
Tests also prove that lubricity and sulphur content do not directlycorrelate.
Can marine fuels with >0.05% fail the test?
Based on automotive experience it is assumed that max WSD of520µm will provide sufficient engine protection.
In view of the severe conditions in a large bore marine dieselengine with regard to fuel pumps (in-line, rotary, reciprocating,common rail) & injectors, in order to ensure complete engineprotection the proposed limit for WSD may need lowering.
Alternatively – use of an established and proven lubricity improverwill provide engine protection from wear and corrosion even whenusing ultra low sulphur distillate fuels.
Stability of MGO
Middle Distillate Instability
Investigations into the causes of middle distillate instabilityhave indicated a number of possible pathways.
Acid-Base reactions
Polymerisation reactions
Esterification reactions
UV initiated reactions
Fuel degradation is a complex series of many reactions,therefore a blend of stability additives often deliver enhancedperformance
Fuel stability additives – benefits of use
11
3
0
2
4
6
8
10
12
Filt
erPa
dR
atin
g
1
Basefuel
Basefuel + Stabiliser
Filter Pad Fuel Stability Rating:1 to 3=Excellent; 4 to 6=Good; 7-9=Marginal; 10-15=Poor; 16-20= Very Poor
Improved thermal stability by ASTM D6468 in European diesel with FOA-31A@ 60mg / l
Innospec FOA Stabiliser Additive Performance
Unagedbase fuel
Agedbase fuel
Aged fuel containingInnospec Additive
Our Fuel Specialties business
MARINE HEATING REFINERY PERFORMANCE POWER FBC
Thank you for your time & attention !Any Questions?