An Experimental Investigation of Fuel Additives in a Supercharged Boiler

1960 ◽  
Vol 82 (3) ◽  
pp. 169-178 ◽  
Author(s):  
R. J. Zoschak ◽  
R. W. Bryers

To permit the use of high-vanadium residual oil as fuel for combined super-charged-boiler gas-turbine power plants, it is necessary to determine the treatment required to prevent the high-temperature corrosion and deposit problems associated with this fuel. A test program has been undertaken wherein a number of magnesium and aluminum-bearing additives have been injected into washed residual oil when firing a laboratory-scale, simulated supercharged boiler. Different tube arrangements within the boiler have been tried. Ash collected on the tubes at various locations has been analyzed and its corrosive effect at high temperatures on some types of stainless steel has been evaluated. The results thus far obtained are presented together with some hypotheses regarding the formation of deposits.

Author(s):  
M. D. Bender ◽  
R. C. Klug

A field test program to validate the high temperature oxidation resistance of the ATI 20-25+Nb™ alloy in a Solar Turbines Incorporated Mercury™ 50 gas turbine engine has exceeded 66,000 operating hours. The primary goal of this program is to assess the effect of the actual recuperator operating environment on the high temperature degradation of primary surface recuperator (PSR) materials. As PSRs are generally fabricated from thin foil materials, excessive degradation can cause perforation or collapse, leading to decreased performance or failure. To avoid such issues, PSRs are generally fabricated from highly-alloyed austenitic stainless steels or nickel-base superalloys. This field test program evaluates and compares the long-term performance of the iron-based austenitic ATI 20-25+Nb™ stainless steel (UNS S35140) with the more highly alloyed nickel-based 625 alloy (UNS N06625) in an in-situ turbine exhaust environment. Sub-size air cell samples of alloy 625 and ATI 20-25+Nb™ alloy, exposed for 66,000 hours (running time) in turbine exhaust, were removed and tested for materials characterization. Analysis showed that both alloys exhibit excellent long-term resistance to environmental degradation, even after service exposures equivalent to over 7.5 years.


Alloy Digest ◽  
1995 ◽  
Vol 44 (3) ◽  

Abstract NICROFER 5520 Co is a nickel-chromium-cobalt-molybdenum alloy with excellent strength and creep properties up to high temperatures. Due to its balanced chemical composition the alloy shows outstanding resistance to high temperature corrosion in the form of oxidation and carburization. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ni-480. Producer or source: VDM Technologies Corporation.


Alloy Digest ◽  
1982 ◽  
Vol 31 (6) ◽  

Abstract Type HN is an iron-chromium-nickel alloy containing sufficient chromium for good high-temperature corrosion resistance and with nickel content in excess of the chromium. This alloy has properties somewhat similar to the more widely used ACI Type HT alloy but with better ductility. Type HN is used for highly stressed components in the 1800-2000 F temperature range. It is used in the aircraft, automotive, petroleum, petrochemical and power industries for a wide range of components and parts. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: SS-410. Producer or source: Various stainless steel casting companies.


Author(s):  
Michele Scervini ◽  
Catherine Rae

A new Nickel based thermocouple for high temperature applications in gas turbines has been devised at the Department of Material Science and Metallurgy of the University of Cambridge. This paper describes the new features of the thermocouple, the drift tests on the first prototype and compares the behaviour of the new sensor with conventional mineral insulated metal sheathed Type K thermocouples: the new thermocouple has a significant improvement in terms of drift and temperature capabilities. Metallurgical analysis has been undertaken on selected sections of the thermocouples exposed at high temperatures which rationalises the reduced drift of the new sensor. A second prototype will be tested in follow-on research, from which further improvements in drift and temperature capabilities are expected.


Author(s):  
Dieter Bohn ◽  
Nathalie Po¨ppe ◽  
Joachim Lepers

The present paper reports a detailed technological assessment of two concepts of integrated micro gas turbine and high temperature (SOFC) fuel cell systems. The first concept is the coupling of micro gas turbines and fuel cells with heat exchangers, maximising availability of each component by the option for easy stand-alone operation. The second concept considers a direct coupling of both components and a pressurised operation of the fuel cell, yielding additional efficiency augmentation. Based on state-of-the-art technology of micro gas turbines and solid oxide fuel cells, the paper analyses effects of advanced cycle parameters based on future material improvements on the performance of 300–400 kW combined micro gas turbine and fuel cell power plants. Results show a major potential for future increase of net efficiencies of such power plants utilising advanced materials yet to be developed. For small sized plants under consideration, potential net efficiencies around 70% were determined. This implies possible power-to-heat-ratios around 9.1 being a basis for efficient utilisation of this technology in decentralised CHP applications.


2019 ◽  
Vol 28 (8) ◽  
pp. 1789-1850 ◽  
Author(s):  
Esmaeil Sadeghi ◽  
Nicolaie Markocsan ◽  
Shrikant Joshi

Abstract High-temperature corrosion of critical components such as water walls and superheater tubes in biomass/waste-fired boilers is a major challenge. A dense and defect-free thermal spray coating has been shown to be promising to achieve a high electrical/thermal efficiency in power plants. The field of thermal spraying and quality of coatings have been progressively evolving; therefore, a critical assessment of our understanding of the efficacy of coatings in increasingly aggressive operating environments of the power plants can be highly educative. The effects of composition and microstructure on high-temperature corrosion behavior of the coatings were discussed in the first part of the review. The present paper that is the second part of the review covers the emerging research field of performance assessment of thermal spray coatings in harsh corrosion-prone environments and provides a comprehensive overview of the underlying high-temperature corrosion mechanisms that lead to the damage of exposed coatings. The application of contemporary analytical methods for better understanding of the behavior of corrosion-resistant coatings is also discussed. A discussion based on an exhaustive review of the literature provides an unbiased commentary on the advanced accomplishments and some outstanding issues in the field that warrant further research. An assessment of the current status of the field, the gaps in the scientific understanding, and the research needs for the expansion of thermal spray coatings for high-temperature corrosion applications is also provided.


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