The oxygen of low-pressure boiler corrodes problem and countermeasure
From;    Author:Stand originally
The anticorrosive problem of rolled steel gets all the time the attention of people, adopt measure to decrease to perhaps put an end to its to happen ceaselessly. With respect to the each metal component of low-pressure industry boiler, because its use condition is abominable, corrode a circumstance more serious, the harm that because corrode,causes is greater also. The article exists with respect to low-pressure industry boiler general and relatively serious oxygen is corroded, from theoretic to its mechanism, feature and influencing factor are mixed produced a process to give elaborate, offerred the way to deal with a situation that prevent.

One, the oxygen of boiler of treasure chicken city corrodes the current situation in recent years, the boiler gross of treasure chicken city already amounted to 1500 or so, because boiler uses an unit to cannot undertake deoxidize by the requirement of GB1576-85, cannot dominate water supply and heat water index effectively, the blemish of structure of oneself of together with boiler, run mode is unreasonable, boiler maintains with not classy, the oxygen that causes boiler pressure part corrodes a phenomenon very serious. According to statistic, the oxygen of different level corrodes boiler stage number to hold sum total about 10% , corrode with the oxygen of boiler of heating hot water especially most serious. In this boiler of 10% , light person make the wall of pressure part large decrease book, lowered the service life of boiler; The person that weigh makes component cannot satisfy working intensity requirement, need is repaired or be forced to discard as useless; More serious person the status that achieved critical explosion, the life property of direct and minatory people is safe.

It is a few models below paradigmatic:

The right header of KZL2-7 steam boiler of ① some unit (the bottom in φ159×mm) , when stopping furnace to examine discovery has the ulcer of one φ120mm to corrode, via eradicating corrosive, discover odd wall is large only 0.5mm;

Boiler of hot water of a DZL120×104-0.7/95/70 just ran ② some unit 2 heating period, the discovery when regular inspection, smoke is in charge of (φ57×3.5mm) ulcer corrodes deepness to already amounted to 2.5mm ~ 3.0mm;

Production of ③ some factory uses boiler KZL4-13, move 6 years, because oxygen corrodes a problem, boiler can step-down moves, cannot satisfy a requirement and discard as useless;

④ some factory SZL10-16 change hot water boiler, drum wall bedding face accumulates ulcer to corrode, deepness amounts to 3.0mm, bilge inside boiler take-over upright ulcer is corroded, ply of tube head the rest only 0.5mm.

2, the mechanism that oxygen corrodes and feature press mechanism, corrode cent for chemistry corrode two kinds big with electrochemistry. General chemistry corrodes the abortion that do not have report to be born, and the generation that electrochemistry corrodes companion to have electricity. To boiler pressure part, water side is corroded with electrochemistry give priority to, igneous side (or flue gas side) corrode with chemistry give priority to. Oxygen is corroded is a kind of electrochemistry is corroded actually, its mechanism is: Because boiler water is a kind of electrolyte that has polarity, below the attraction of the polarity element of water, the one part iron of rolled steel surface is atomic, begin immigrant heat water and become the iron ion that carries positive electricity, and the electron with the redundant reservation on rolled steel takes negative electric charge. If iron ion enters boiler water ceaselessly, make armor plate (canal) go up to appear gradually hole hole, arose to corrode. The dissolved oxygen in boiler water has depolarization to change intention, can make aggravate of this one process. And what depolarization changes intention is strong more or less to concern with the quantity that contain oxygen infirmly, that is to say what more or less is the content of dissolved oxygen deciding to corrode is strong weak, and direct ratio of both thread sex concerns, if pursue,1 is shown. The graph contains oxygen quantity and the relationship that corrode speed in 1 water
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