Dr D Daniel
Applications accepted all year round
Self-Funded PhD Students Only
About the Project
Fossil fuels are currently the major energy source with approximately 80% of total energy consumption of the world. Renewable energy including traditional biomass contributes to about 14%. The biomass energy itself is holding 9.6% of the consumption. There are many advantages of biomass energy source such as inexhaustible, landfill reduction, and relatively low cost. The sources of biomass can be rich husk, sugarcane, wooden chip, corn waste, and palm waste. Interest in the use of circulating fluidized bed boilers is rising fast especially in emerging economies. Its potential for reliable operation with difficult-to-burn fuels like petcoke, waste and biomass made it attractive to large number of industries ranging from small process plants to very large utility companies. It has many advantages including uniform temperature distribution, large solid–gas exchange area, high heat transfer coefficients between bed and heat exchanging surfaces, ability to handle a wide range of fuels having different sizes, shapes, moisture contents and heating values, and stable combustion operation at low temperatures (≈850 °C). However tube erosion and also corrosion on the heat exchanger surfaces can cause the boiler downtime.
It has been also reported that the corrosion problem associated with the alkali chloride deposits in biomass-fired boiler. The most severe corrosion problems in biomass-fired systems are expected to occur due to Cl-rich deposits formed on superheater tubes. The presence of alkali chloride salts in deposits may cause accelerated corrosion well below the melting point of the salt. Alkali chlorides, especially potassium chloride, increased the corrosion rate of the materials used as superheater tubes. Reactions between the metallic surface and this species, or other alkali-containing species such as carbonates, have to be avoided in order to increase the corrosion resistance of the superheaters. Therefore, their failure or/and corrosion mechanism should be extensively studied in order to extend the life time of the tubes in the service atmosphere.
The physico-chemical characterization of oxide scale should be first investigated by X-ray diffraction, SEM equipped EDS.
The oxide thickness and type of oxide should be also examined. It is possible that some of phase contamination may appear in the oxide scale. The mechanism of oxide growth can be predicted by these characterization.
After this analysis, the atmosphere can be simulated by mixing of basic gases. The study of corrosion kinetics of uncoated- and coated samples can be then carried out in the simulated atmosphere for predicting the life time in service atmosphere. The reaction mechanism can be further discussed in this study.
Objectives
• Understand the failure mechanism of uncoated samples under service conditions
• Study the abrasion/erosion resistant and thermal properties of uncoated and coated samples
• Study the corrosion kinetics of uncoated- , and coated samples at service temperature for longer duration of time.
• Predict life time of uncoated and coated samples subjected to service atmosphere
Funding Notes
There is no funding for this project: applications can only be accepted from self-funded candidates
References
[1] R. Saidur, E.A. Abdelaziz, A. Demirbas, M.S. Hossain, S. Mekhilef, A review on biomass as a fuel for boilers, Renew. Sus. Energ. Rev. 15 (2011) 2262–2289.
[2] A. Arjunwadkar, P. Basu, B. Acharya, A review of some operation and maintenance issues of CFBC boilers, App. Therm. Eng. 102 (2016) 672–694.
[3] A.A. Khan, W. de Jong, P.J. Jansens, H. Spliethoff, Biomass combustion in fluidized bed boilers: Potential problems and remedies, Fuel Process. Technol. 90 (2009) 21-50.
[4] H.P. Nielsen, F.J. Frandsen, K. Dam-Johansen, L.L. Baxter, The implications of chlorine-associated corrosion on the operation of biomass-fired boilers, Prog. Energ. Combust. Sci. 26 (2000) 283–298.
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