High-Temperature Corrosion in Gas Turbines and Steam Boilers by Fuel Impurities—Part VII: Evaluation of Magnesium-Aluminum-Silicon Combinations as Corrosion Inhibitors

1976 ◽  
Vol 98 (4) ◽  
pp. 511-516 ◽  
Author(s):  
W. R. May ◽  
M. J. Zetlmeisl ◽  
R. R. Annand
Keyword(s):  
High Temperature ◽  
Linear Regression ◽  
Corrosion Inhibitor ◽  
Gas Turbines ◽  
Corrosion Inhibitors ◽  
High Temperature Corrosion ◽  
Regression Analyses ◽  
Stepwise Linear Regression ◽  
Fuel Ash ◽  
Steam Boilers

Aluminum, alone and in several combinations with magnesium and silicon, has been evaluated as a corrosion inhibitor and slag modifier for heavy fuel ash. Stepwise linear regression analyses were carried out on the data and the results are compared with earlier data on magnesium and silicon. The Mg-Al-Si combination gives superior tolerance to aggravation of corrosion caused by sodium. It gives the slag a friability equivalent to Mg-Si combinations.

High-Temperature Corrosion in Gas Turbines and Steam Boilers by Fuel Impurities: IV—Evaluation of Silicon and Magnesium-Silicon as Corrosion Inhibitors

1974 ◽  
Vol 96 (2) ◽  
pp. 124-128 ◽  
Author(s):  
W. R. May ◽  
M. J. Zetlmeisl ◽  
R. R. Annand
Keyword(s):  
High Temperature ◽  
Magnesium Sulfate ◽  
Vanadium Pentoxide ◽  
Sodium Sulfate ◽  
Gas Turbines ◽  
Corrosion Inhibitors ◽  
High Temperature Corrosion ◽  
Corrosion Rates ◽  
Steam Boilers

The corrosion rates of Udimet™ 500 in a variety of sodium sulfate-silica-vanadium pentoxide and sodium sulfate-magnesium sulfate-silica-vanadium pentoxide slag compositions were measured electrochemically at temperatures up to 950 deg. The weight ratios of the elements, sodium, silicon, and magnesium to vanadium were defined for acceptable corrosion rates. A simple burner test for slag evaluation is described. Characteristics of slags produced by magnesium, silicon, and magnesium-silicon in conjunction with sodium sulfate and vanadium pentoxide are discussed. Results indicate that the magnesium-silicon combination produces a slag which is equally as low as magnesium in corrosivity and superior in slag characteristics.

High-Temperature Corrosion in Gas Turbines and Steam Boilers by Fuel Impurities—Part V: Lead Containing Slags

1975 ◽  
Vol 97 (3) ◽  
pp. 441-447 ◽  
Author(s):  
M. J. Zetlmeisl ◽  
W. R. May ◽  
R. R. Annand
Keyword(s):  
High Temperature ◽  
Linear Polarization ◽  
Gas Turbines ◽  
Sodium Level ◽  
High Temperature Corrosion ◽  
Corrosion Rates ◽  
Polarization Technique ◽  
Steam Boilers

The effect of lead on the corrosivity and friability of slags containing various ratios of sodium, vanadium, magnesium, and silicon has been evaluated. The application of the linear polarization technique was demonstrated. Lead produces very corrosive melts and tenacious slags. Magnesium will inhibit corrosion to acceptable levels and produce friable slags at 800 °C with a 4 to 1 ratio of additive to vanadium plus lead and a sodium to vanadium plus lead ratio no greater than 0.1. To produce friable slags at 900°, sodium must first be reduced to a sodium to vanadium plus lead ratio of 0.01. Second, a magnesium-silicon additive must be used at a 6 to 1 ratio of additive to vanadium plus lead. The corrosion rates of lead containing melts increases rapidly with sodium level.

Fatigue in multiple sclerosis: relation to depression, physical impairment, personality and action control

2007 ◽  
Vol 13 (9) ◽  
pp. 1161-1167 ◽  
Author(s):  
I.-K. Penner ◽  
N. Bechtel ◽  
C. Raselli ◽  
M. Stöcklin ◽  
K. Opwis ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Linear Regression ◽  
Action Control ◽  
Physical Impairment ◽  
Healthy Controls ◽  
Regression Analyses ◽  
Physical Fatigue ◽  
Stepwise Linear Regression ◽  
Main Factor

Athough fatigue is one of the most common symptoms of multiple sclerosis, it is yet poorly understood and therefore difficult to manage. To clarify the nature of fatigue we investigated its relationship to depression, physical impairment, personality and action control and compared these variables between a sample of 41 MS patients and 41 healthy controls. Physical impairment was assessed by the EDSS and all other dimensions, using questionnaires. Stepwise linear regression analyses revealed that physical impairment was related to physical fatigue in MS patients. Depression was the main factor influencing fatigue among both, MS patients and controls. What clearly differentiated the two groups was the correlation between fatigue and action control. Decreased levels of action control imply attentional and motivational deficits and were only found in fatigued MS patients. Our study indicates that motivational disturbances might be specific for MS related fatigue. Multiple Sclerosis 2007; 13: 1161—1167. http://msj.sagepub.com

Use of Chromium Containing Fuel Additive to Reduce High Temperature Corrosion of Hot Section Parts

2000 ◽  
Author(s):  
Jean-Pierre Stalder ◽  
Peter A. Huber
Keyword(s):  
High Temperature ◽  
Hot Corrosion ◽  
Gas Turbines ◽  
High Temperature Corrosion ◽  
Fuel Oil ◽  
Fuel Additive ◽  
Fuel Quality ◽  
Common Belief ◽  
Heavy Fuel Oil ◽  
Fuel Treatment

The use of “clean” fuel is a prerequisite at today’s elevated gas turbine firing temperature, modern engines are more sensitive to high temperature corrosion if there are impurities present in the fuel and/or in the combustion air. It is a common belief that distillate grade fuels are contaminant-free, which is often not true. Frequently operators burning distillates ignore the fuel quality as a possible source of difficulties. This matter being also of concern in plants mainly operated on natural gas and where distillate fuel oil is the back-up fuel. Distillates may contain water, dirt and often trace metals such as sodium, vanadium and lead which can cause severe damages to the gas turbines. Sodium being very often introduced through contamination with seawater during the fuel storage and delivery chain to the plant, and in combination, or with air borne salt ingested by the combustion air. Excursions of sodium in treated crude or heavy fuel oil can occur during unnoticed malfunctions of the fuel treatment plant, when changing the heavy fuel provenience without centrifuge adjustment, or by inadequate fuel handling. For burning heavy fuel, treatment with oil-soluble magnesium fuel additive is state of the art to inhibit hot corrosion caused by vanadium. Air borne salts, sodium, potassium and lead contaminated distillates, gaseous fuels, washed and unwashed crude and residual oil can not be handled by simple magnesium based additives. The addition of elements like silicon and/or chromium is highly effective in reducing turbine blade hot corrosion and hot section fouling. This paper describes field experience with the use of chromium containing fuel additive to reduce high temperature corrosion of hot section parts, as well as the interaction of oil-soluble chromium and magnesium-chromium additives on material behaviour of blades and vanes, and their economical and environmental aspects.

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