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.