Some Problems Encountered in Sampling Open Hearth Stacks
J. H. Smith, G. L. Rounds, H. J. Matoi · Air Repair · 1953
A number of problems are encountered, in open hearth sampling, due to conditions inherent with basic open hearth furnace operations.A summary of some of these conditions will be presented.The summary will, in turn, be followed by a description of a typical sampling procedure, pointing out the specific problems introduced by these conditions.I. Stack Conditions A. The moisture content of the open hearth stack gases is about 7-8% by volume with a dew point in the neighborhood of 100°F.This necessitates heating portions of the sampling train to prevent undesired condensation from occuring in the equipment.B. Temperatures, in the stack at the sampling point, are approximately 1100°F without a waste heat boiler, and approximately 500°F with a waste heat boiler.This necessitates selection of equipment to withstand thermal failure.C. The presence of an oxidizing atmosphere at elevated temperatures introduces the problem of corrosion.The major gaseous constituents present in the stack are: Constituent Percent CO., 8-9%