The Role of Chemical Thermodynamics in Analyzing Gas-Side Problems in Boilers

Abstract

Part 1 deals with equilibrium concentrations of twenty-nine gaseous and five condensed constituents which were calculated for the combustion gases from two coals. Temperatures ranged from 440 to 3140 F and fuel-air ratios from 90 to 130 per cent of theoretical air. Results are presented in graphical and tabular form paying particular attention to sodium, sulfur, and chlorine compounds. A few of the many possible inferences relevant to fouling, corrosion, and air pollution are pointed out. Starting from the equilibrium-gas-composition results of Part 1, the regions of thermodynamic stability of various sodium and iron compounds are obtained in Part 2 as functions of temperature and fuel-air ratio. It is shown that purely thermodynamic considerations impose an upper temperature limit upon corrosion mechanisms involving complex iron sulfates. An explanation is advanced for the severe fouling tendency of high alkali coals.

Discussion: “Gas-Side Corrosion in Coal and Oil-Fired Utility Units” (Mount, C. L., and Wiedersum, G. C., 1965, ASME J. Eng. Power, 87, pp. 250–257)

“…347 corrosion rate was no different. 6 We have run thirty-day burn tests on four of our major coals using a corrosion probe to maintain desired high metal temperature. These tests have revealed one coal to have a much higher corrosion factor.…”

Optical methods and results of dew point and deposition rate measurements in salt/ash‐containing combustion gases—B2O3(I) deposition rates by interference methods and comparisons with theory

“…and the intake air contains sodium chloride (about 0.01-10 ppm by wt., as in the marine environment). Similarly, aggressive condensates result from the presence of vanadium in fuel oil, and ash and sulfur in coals used for conventional power generators (Boll and Patel, 1961;Jackson, 1977) or magneto-gas-dynamic (Dicks et al, 1977;Heywood and Womack, 1969) types. [See Halstead and Raask (1969), Stearns et al (1982), and Hedley et al (1966) for a useful overview of this area.]…”

Portable Total Energy Package for Advanced Base Functional Components

“…In a study which showed that 2.0 sulfidation is thermodynamically predicted if oxygen is absent from the metal 7. surface, Boll and Patel (1961) established ' a second important aspect of high-temperature corrosion. They found that at a 1.0 high temperatures, Na 2 SO 4 (a stable c liquid at about 1,6000F) in contact with ' high-alkali combustion gases allowed sulfidaticn to occur in marine gas 0 turbines rn which the temperature of 1,000 …”