Prevention Methods and Mechanism Of Boiler Hot End Corrosion

Prevention Methods and Mechanism Of Boiler Hot End Corrosion

Mechanism Of Hot finish Corrosion

The Hot end Corrosion within the boiler is because of the presence of atomic number 11, vanadium, and sulfur within the fuel. throughout and once the combustion they react and kind oxides, sulfates, and vanadates.

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Even a small quantity of the higher than constituents could cause dross deposits on the boiler tubes and induce corrosion. this kind of corrosion is named Hot finish Corrosion.

The fuel having but regarding one hundred ppm of vanadium thought-about|is taken into account} an occasional vanadium fuel and higher than two hundred ppm it’s considered as high metallic element fuel.

Sodium and vanadium contamination cause corrosion and dross deposits only the temperatures ar at or higher than their melting points. once each vanadium and metallic element ar present, the tendency to cause corrosion is larger than once either is present alone.

The vanadium reacts with gas to make numerous oxides within the boiler chamber. because of warmth within the furnace region, the various variety of vanadium oxides continue the metal and forming dross.

The deposits promote the transport of O2 to the metal surface. Corrosion is caused by the mix of oxide layer fluxing and continuous oxidization by transported O2.

If the temperature is low, they submit to the boiler as ash. commonly this drawback happens once the steam temperature is quite 538oC or higher. there’s no sense due to cut back the vanadium content in heavy fuel.

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Prevention methods

The following ar the bar ways to manage hot finish corrosion in boilers.

Reducing Excess Air

The corrosion because of vanadates may be reduced by lowering the number of excess air into the combustion. Thereby it reduces the assorted variety of vanadium oxides and sulfur trioxide. the surplus air offer shall maintain but the five hundred of total airflow into the boiler

Material of Construction

Using of High-chromium alloys can cut back the new finish corrosion. a number of the high chromium alloys ar C-276, Alloy 625, five hundredth atomic number 28 five hundredth metal or 400 nickel 60 minutes chromium.

Fuel Additives

Fuel additives like metal and aluminum oxides are no-hit in dominant the high-temperature corrosion issues. The additives perform is to elevate the temperature of the deposits. Enough periclase should be added to alter the bimetallic constituents to stay within the solid section as they contact the metal surface.

Lower Fuel Ash Content

Fuel oil contains quite zero.05% ash ar thought of high ash fuels. On the opposite hand, if the fuel contains but zero.02% ash ar thought of low ash fuels.

If additional ash content is present within the fuel, it’ll produce additional deposition on the metal surface and cause corrosion.

It’s forever suggested to pick the fuel having lower ash contain.