-Boiler
PANEL DISCUSSION.
Water Chemistry
..
What’s New in Boiler Water Chemistry J
A. A. BERK, iMODERATOR
E. P. PARTRIDGE,
Zndustrial Water Branch,
COMODERATOR
Bureazc of Mines, College Park, M d .
Hall Laboratories, Pittsburgh, Pa.
T h e purpose of this session is to present an omnibus report on recent developments in the field of boiler-water chemical engineering. A panel of experts is ready to summarize for you the newer literature and, in some instances, unpublished information on chemical cleaning of boilers; on preparation of the boiler feedwater; on treatment to prevent corrosion, encrustation, and carry-over j and on chemical treatment to prevent corrosion by condensed steam. The evolution of the modern steam generator has been made possible by a partnership of advances in mechanical engineering design, progress in physical metallurgy, and new chemical engineering skills in water conditioning. It is an indication of this evolution that embrittlement cracking of boiler seams, relatively recently an important topic of panel discussions, can now be covered briefly as a minor aspect of boiler corrosion that we have learned to control. The emphasis now is on economy of fuel through clean boilers and clean turbines; the preservation of the expensive boiler and its auxiliaries from corrosion, fouling, and over-heating j and the dependable availability of the steam-generating and steam-utilizing plant. Each of the experts will summarize “what’s new” in his assigned topic.
Internal Cleaning of Boilers J. R11. MALONEY Hall Laboratories, Chicago, I l l .
R
EMOVING scales and deposits formed on the evaporative
metal surfaces of steam generating units has been successfully accomplished for the past several years by means of inhibited acid solvents. Because of the dangers involved in most chemical cleaning practices plus the difficulties encountered in adding large volumes of acid to the unit and controlling both temperature and acid strength, this work is usually assigned to specialists engaged in acid cleaning operations. In general, t h e chemical cleaning procedure is done in four major steps: May 1954
1. Sufficient inhibited acid solvent is added to the boiler through a lower boiler coniiectioii and the proper acid strength and temperature are maintained. 2. The chemical solvent remains in the unit from 6 to 8 hours. This is appropriately termed the “soaking period.” 3. The boiler is drained and sufficiently rinsed with clear water. 4. Finally, metal surfaces are neutralized by means of a 3to 4-hour boil with an alkaline solution.
The basic solvent used in removing the common constituents found in boiler deposits is approximately a 5 % solution of hydro-
I N D U S T R I A L AND E N G I N E E R I N G CHEMISTRY
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