Monthly Archives: June 2022

Sulfuric acid dew point Corrosion

Sulphuric acid dew point corrosion or cold end corrosion occurs due to the condensation of sulphuric acid and is commonly observed in components which are exposed to product of combustion . ie Boiler or an engine. sulphuric is present in heavy oil and during combustion, Sulphur oxide are generated . a small portion of which become SO3 , as the exhaust gas temperature reaches the dew point or lower , vapor-phase sulfuric acid form . f the sulphuric acid vapor contacts the lower – temperature metal surface it may condensate as liquid sulphuric acid and corrode the metal

Source – SA Hasan Linkedin

Mechanical Wear Protection calculation

How to calculate mechanical wear , Stribeck Curve explain how to increase protection equipment agains mechanical wear

control related wear , film thickness and coefficient of friction for boundary lubrication , mixed film lubrication and hydrodynamic lubrication

Factor Influence Corrosion

Factor Influence for Corrosion

Environment effect : Degree of Aeration , Flow Velocity , Impurities , pH , Temperature , Concentration of Corrodents

Material Effect : Surface Condition , Composition , Micro Structure , Hot/Cold Hardening

Stress Effect : Design Factor, Fabrication , Metallurgy Factor

Blast Furnace Construction

BLAST FURNACE

The blast furnace is a counter-current gas/solids reactor in which the descending column of burden materials [coke, iron ore and fluxes/additives] reacts with the ascending hot gases. The process is continuous with raw materials being regularly charged to the top of the furnace and molten iron and slag being tapped from the bottom of the furnace at regular intervals.

Key steps of the process are as follows:

1. upper part of the furnace – free moisture is driven off from the burden materials and hydrates and carbonates are disassociated.
2. lower part of the blast furnace shaft – indirect reduction of the iron oxides by carbon monoxide and hydrogen occurs at 700-1,000°C.
4. Bosh area of the furnace where the burden starts to soften and melt – direct reduction of the iron [and other] oxides and carbonization by the coke occurs at 1,000-1,600°C. Molten iron and slag start to drip through to the bottom of the furnace [the hearth].
   Between the bosh and the hearth are the tuyeres [water cooled copper nozzles] through which the blast – combustion air, preheated to 900-1,300°C, often enriched with oxygen – is blown into the furnace. Immediately in front of the tuyeres is the combustion zone, the hottest part of the furnace, 1,850-2,200°C, where coke reacts with the oxygen and steam in the blast to form carbon monoxide and hydrogen [as well as heat] and the iron and slag melt completely.
   Molten iron and slag collect in the furnace hearth. Being less dense, the slag floats on top of the iron. Slag and iron are tapped at regular intervals through separate tap holes. For merchant pig iron production, the iron is cast into ingots; in integrated steel mills, the molten iron or hot metal is transferred in torpedo ladle cars to the steel converters. Slag is transferred to slag pits for further processing into usable materials, for example raw material for cement production, road construction, etc.

Source : metalurgica engineering

Corrosion Risk Planning for Storage Tank

Risk Planning activity for a Storage Tank

What should form an integral part of a quality management system which includes corrosion risk planning for a tank?

What areas should one look at when planning for design/maintenance/inspection of a tank?

1.Inner walls – Risk :
Coating degradation
Corrosion due to water/dissolved oxygen

2. Outer walls/roof – Risk :
Atmospheric corrosion
coating degradation due to moisture + UV radiation + temperature

3. Pipes – Risk :
Atmospheric corrosion
Coating degradation

4. Railing – Risk :
Coating degradation
Wrong coating selection based on pure aesthetics
coating damage at joints and bends

5. Breather valve – Risk :
uniform corrosion/pitting depending on whether it is made up of carbon steel/stainless steel
Galvanic couple at the joining/welding point of valve to roof

Source : Linkedin , Pic : Pexel