Experimental Boiler Research Articles

Sulfuric Acid Corrosion in Oil-Fired Boilers—Studies on Sulfur Trioxide Formation

Abstract Experimental studies on economizer and air-heater corrosion resulting from the formation of sulfuric acid in residual-oil-fired boilers are described. Factors controlling the oxidation of sulfur dioxide to sulfur trioxide have been investigated in a small experimental boiler. The fuel used was a distillate oil to which synthetic compounds were added to simulate the sulfur and metallic components commonly found in residual oils. The sulfur trioxide content of the flue gases was determined indirectly by measuring the corrosion of and sulfate deposition on a steel specimen maintained at a controlled temperature. In an initially clean boiler, approximately equal quantities of sulfur trioxide formed in the flame, furnace, and convection sections, while less formed in the economizer-air heater section. Nickel, iron, sodium, and vanadium in the fuel each decreased the corrosion normally experienced by the test specimen, the magnitude of the effect increasing in the order given. Deposits of these metallic fuel-ash components in the boiler had a relatively small effect on the corrosion of the test specimen. Only the iron deposits indicated significant catalytic activity for the oxidation of sulfur dioxide to sulfur trioxide. Combinations of sodium and vanadium in the fuel were found to decrease corrosion in an initially clean furnace, but boiler deposits from certain combinations of these elements were found to increase corrosion substantially. This catalytic effect is predominant over extended periods of time.

Experimental Boiler Studies of the Breakdown of Amines

Abstract A report of the results obtained when several types of amines were tested for breakdown to ammonia in an experimental boiler. Test pressures ranged from 250 to 2500 psi and temperatures from 400 to 1200 F. Test results indicate that morpholine, which has been used successfully at 1600 psi and 1000 F, also shows relatively good stability at 2500 psi and 1200 F.

The New Kearny Generating Station: Public Service Electric and Gas Company

Abstract The author describes the more important features of the design of the new Kearny Generating Station and points out the significant differences between Kearny and Sewaren. Outstanding features are the steam conditions, 2350 psig, 1100 F–1050 F; pressurized firing of boilers; controlled circulation in boilers; gas recirculation; side-exhaust turbines with twin condensers and no expansion joint between turbine and condenser; an experimental high-speed boiler feed pump; and a completely austenitic main steam system.

Experimental Study, Feedwater Treatment for 1400-Lb Boiler Operating Pressure

Abstract Study has shown that the future steam and electrical loads of the Dye Works of the author’s company would he most economically supplied by a 1400-psi boiler-and-turbine installation, exhausting directly into the plant process mains, without the use of evaporators as are now-used at the Deepwater plant of the Deepwater Operating Company. The development of a satisfactory water-purification system to permit 100 per cent treated soft water to be used in a 1400-lb boiler would eliminate the necessity of using Intermediate evaporators with their consequent maintenance and loss of thermal potential. It has been calculated in connection with the study of increased steam and electrical capacity for the Dye Works that the elimination of the evaporators would permit the generation of up to 8000 kw of electricity from the same steam. Additional savings in maintenance would be realized. This paper reviews the various steps undertaken in developing, installing, and operating the experimental water-treatment system, followed later by the installation of a 1400-lb experimental boiler, operating with a heat absorption of 100,000 Btu per sq ft per hr. A 400,000-lb per hr boiler to operate at 1400 psi with 100 per cent treated soft water has been purchased and will start operation in January, 1942.

The Formation and Thermal Effects of Calcium Sulphate Boiler Scale

Abstract A fundamental study of the manner in which calcium sulphate scale forms upon an evaporative surface, a redetermination of the solubility values for calcium sulphate in the boiler temperature range, and measurements of the rate of formation and heat conductivity of calcium sulphate scales produced in an experimental boiler, are described in abstract in this paper. Evidence is presented to show that the initial deposition of calcium sulphate scale takes place as the result of the evolution of bubbles, either of dissolved gas or of steam, from an evaporative surface, and that the continued growth of scale is dependent upon the fact that the solubility of calcium sulphate decreases with temperature increase. The work of the authors thus presents a new explanation of the mechanism of initial scale formation, supports Hall’s theory of the growth of scale, negates the colloidal theory of scale formation, and offers a fundamental basis for the study of scale-prevention methods. Photomicrographs of the early stages of deposition and growth of calcium sulphate scale are shown, as well as photomicrographs of scales produced under varying conditions. From the results of their own work and from that of other investigators, the authors present a discussion of the present knowledge concerning calcium sulphate scale. While the effect of scale upon heat utilization in modern boilers is believed to be very slight, calculations based on the heat conductivity of anhydrite scale indicate the importance of preventing overheating of tubes due to the insulating effect of scale deposits within them.

Experimental steam boiler explosions

Experimental steam boiler explosions