A Laboratory Slagging Test for Boiler-Furnace Refractories

Abstract

This paper gives particulars of a simulative service test of refractories with coal-ash slag made in a laboratory furnace in which the test brick form the lining of a cylindrical chamber rotated about a vertical axis. Powdered slag or a mixture of slag with powdered coal is fed at a uniform rate through the gas burner which heats the furnace, impinging on the vertical faces of the brick and flowing out through the bottom of the furnace. Temperature and atmospheric conditions are controlled and the test brick receive equal slag treatment. Comparison of slag effect on the refractories is made by volume loss per unit area of exposed surface.

Tests have been made with slags representing coals used at five power stations where field tests were conducted, and the results are presented by the author. He finds that the relative effects of these different slags at a furnace temperature of 2900 deg. fahr. varies with the composition and fusibility of the coal ash. Further, the erosion of the refractory is dependent on the viscosity of the slag and increases in direct proportion to the furnace temperature. Tests made at temperatures corresponding to those in the boiler furnaces produce similar action on the refractories, as indicated by petrographic examinations. The relative resistance of refractories of different composition and physical structure is not the same for different slags.