Fuel energy conversion processes in gas turbines are not limited to those occurring in the combustion unit. It however extends to processes involving microbial conversion of fuel components and subsequent accumulation of biological material. This salient form of energy conversion occurs majorly in the fuel storage tank and along the fuel systems, where it exert effects such as metal corrosion in the tank, combustion chamber and downstream unit of the turbine, degradation of fuel components, fuel destabilization, clogging of fuel filtering and distribution units and other fuel physical and chemical changes. Of recent concerns are gas turbines operating on biofuels and blends, since biofuels are said to be more highly susceptibility to biodegradation than conventional fuels. This paper aims to review microbial contamination in gas turbines in recent years and discuss the effects of fuel quality on gas turbine performance and efficiency as well as highlight the benefits that can be gained from enhanced predictive maintenance and control.

1. Salient Energy Bio-Conversion Processes Limiting
Gas Turbine Engine Performance Efficiency
Tosin Onabanjo*; Giuseppina Di Lorenzo
School of Energy, Environmental and Agrifood (SEEA), Cranfield University
1

2. Outline 2
— Background on Bio-conversion
— Industry Overview
— Research Barriers
— Next Steps in Predictive Condition Monitoring

3. Bio-conversion (1) 3
 The conversion of organic matter, into a source
of energy through the action of microorganisms.
Organic
Matter
Carbon
Source
Energy
 Definition

4. Bio-conversion (2) 4
 microbial fuel cell
 anaerobic digestion
 fermentation
 bioremediation
 Concept of Bioenergy

5. Bio-conversion (3) 5
 Hydrocarbon loss
 Sludge accumulation
 Induced corrosion
 Physiological changes
 Chemical changes
 Observed effects

6. Bio-conversion (4) 6
 Component Failure
Injectors, Filters, Fuel line, Wall Liner, Blade fouling
 Reduced Engine Performance
 Increased smoke tendency and particulate emissions

7. Industry Overview (1) 7
 History

8. Industry Overview (2) 8
 History to Future

9. Industry Overview (3) 9
 Microbes: bacteria, mould, yeasts
 Mechanisms of contamination: rust, dust,
soil, air, water, fuel
 Mechanisms of hydrocarbon degradation:
aerobic, anaerobic, acid-producing,
symbiotic
 Successes & Challenges

10. Industry Overview (4) 10
 Ecology: fuel-water interphase
 Bio-surfactant, Biofilms
 TEA: O2, NO3, SO4, CO2
 Growth factors: pH, Temp., Water,
nutrients, enhancer/inhibitor
 By-products: sludge, sulphide, water, CO2
 Biocides
 Successes & Challenges

11. Industry Overview (5) 11
 Good Handling Practices
 Biocide Application
 Water Elimination
 Routine Inspection
 Successes & Challenges

12. Research Barriers (1) 12
How much degradation occurs during an
opportunistic window of growth
 Opportunistic gap
 Water consistent in fuels
 Complex microbial systems
 Asymptomatic reactions

13. Research Barriers (2) 13
 Hydrocarbon loss –degree?
 Sludge accumulation – microbial
% and chemical %?
 Induced corrosion – microbial %
 Physiological changes – Sig.?
 Chemical changes – Sig.?

14. Research Barriers (3) 14
 Component Failure
Injectors, Filters, Fuel line, Wall Liner, Blade fouling
 Reduced Engine Performance
 Increased smoke tendency and particulate emissions
 Metal Corrosion
Degree?

15. Research Barriers (4) 15
Root Cause Analysis
 Microbes identification
 Detection (simple to complex)
 Control including biocides
x Reactive
x Symptomatic
x Cost intensive
x Cause-effect relationship
 Traditional approach
Microbiological Examinations Engineering
x Misdiagnosis
x Non-detection
x Parallel research
x Underestimation/Overestimation
x Drug resistance

16. Next Steps for
Predictive Condition Monitoring (1) 16
Systematic Analysis
 Root cause analysis –advance microbiology
techniques
 Modelling: fuel chemical kinetics, microbial kinetics,
abiotic factors, bio-energetics
 Gross observation –representative sampling
 Engineering
x Proactive
x Reduce downtime
x Reduced associated
cost
x Increased
understanding
x Predictive
maintenance and
condition monitoring
x Reduced pressure on
microbial evolution
 Optimized approach

17. Next Steps for
Predictive Condition Monitoring (2) 17
 First time development of an engine
bio-fouling model
• Estimate hydrocarbon loss
• Relate to engine performance and
emission analysis
PowerEnergy2015-49657
July 01, 2015 01:00 PM - 02:45 PM
Application of BIO-fAEG, a biofouling assessment model in gas turbines …
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You