Typical location of Corrosion on Heat Exchanger

There are 4 main reasons that cause corrosion in heat exchangers to need to be concerned during the inspection: Water impingement, Temperature, Vibration, Velocity. Refer to: Corrosion in Heat Exchanger Likely Location of Corrosion – Heat Exchanger Tubes at Baffle;  Heat Exchanger Tubes in the Baffle Plates area are highly prone to corrosion. Due to the possibility of vibration of the Tubes causing friction with the Baffle (Vibration fretting) or Erosion from Fluid flow in Heat Exchanger For smaller tubes, The corrosion of the Tubes on the Baffle can be checked using a hammer. If the Tubes in the Baffle area is thin … Continue reading Typical location of Corrosion on Heat Exchanger

What is Vibration induce cracking

Vibration Induced Fatigue;  Vibration Induced Fatigue is a form of fracture due to fatigue, mechanical (of mechanical Fatigue) due to Dynamic load caused by vibration ( with Vibration) had done so at the risk of Vibration Induced Fatigue is a point there. High stress and severe shaking points. This type of damage is usually found at the small branch connections of Pressure Vessel and Piping, which are naturally high-stress points because they are discontinuous (see Stress Analysis) and are the receiving points. Vibrating force Thus, if the Support inadequate and the Small Branch Connection with Vibration ( for example, near … Continue reading What is Vibration induce cracking

What is Vortex Breaker

Vortex in Vessels;  Vortex, or vortex in Vessels, is the rotation of a liquid’s core while releasing or transferring liquid from Vessels. This appears to be caused by the Earth’s rotation. Vortex can be easily observed. In everyday life, such as flushing the toilet Releasing water from the sink or bathtub Vortex in Vessels will take gas or vapor into the liquid stream that is transferred out. This will make the refining process less efficient, the system has more pressure drop, causing Erosion from the two-phase flow at the nozzle or pipe connecting to the vessel and causing cavitation at … Continue reading What is Vortex Breaker

What is Static Head of vessel

What is “Static Head” in ASME Section VIII Vessels?  In designing the Pressure Vessels according to the ASME Section VIII Division 1, aside from not only considering the design pressure that will occur within the Pressure Vessel, but we also need to consider the weight of the Liquid within the  Vessel acting on it. The pressure caused by the weight of Liquid in Vessel is the “Static Head” which is based on the density of the liquid (Liquid Density called the p) and will have greater value as the height of the liquid from the bottom of the tank or Bottom of … Continue reading What is Static Head of vessel

What is Caustic corrosion cracking

External Evidence of Caustic Leaking; Carbon Steel Piping used for Caustic Service (NaOH content) may be damaged by Caustic Cracking, especially in areas with welded and discrete areas that have high stress. Caustic leaks or leaks from the cracks will look like White salt, which can be seen with the naked eye. Therefore, when doing an external visual inspection for Caustic Piping, don’t forget to look for “White Salt” which is an Evidence that indicates that our Caustic pipe is leaking. External Evidence of Caustic Leaking – Caustic Cracking on Socket Welded Piping;  Example of Caustic leakage from Caustic (NaOH) Injection Piping … Continue reading What is Caustic corrosion cracking

Circumferential vs Longitudinal Stress

Circumferential vs Longitudinal Stress of a Cylindrical Shell in ASME VIII Vessels;  Let’s look at the formula for calculating the Cylindrical Shell thickness of the ASME Section VIII Pressure Vessel. We can see that the Minimum Thickness calculated from Circumferential Stress is approximate twice the thickness calculated from Longitudinal Stress. This is because the Circumferential Stress is twice as much as Longitudinal Stress. Therefore, when calculating Shell thickness, use the formula of Circumferential Stress. Refer to: What is Hoop Stress in pressure vessel? Continue reading Circumferential vs Longitudinal Stress

What is Soil Corrosion

Soil to Air Interface – Zone of Corrosion on API 570 Piping; The area where the pipelines fall underground, or soil-to-air interface, is the area that has a high chance of external corrosion if Wrapping or Coating is damaged. Due to the difference in temperature, humidity and oxygen in the area, the API 570 stipulates that 6 inches above and 12 inches below the soil surface is the Soil-to-air Interface zone that should be Reviewed. Inspection of Soil-to-air Interface for Underground Piping;  For example, to monitor underground pipes ( Underground, Piping) in a pipe underground or Soil-to-air Interface by digging tube down … Continue reading What is Soil Corrosion

Vessel rubber lining inspection

Vessel and Tank Inspection – Rubber Lining Inspection;  Within the Piping, Vessel or Tank, some will be done with Lining or Coating to Prevent Corrosion and Erosion. During inspection (in-service), damages that will occur to the Lining, such as separation, breakage, swelling. If we find that Lining damage. We have to dismantle the lining to check for damage to the metal surface of the Vessel beneath the lining (in the picture is an example of the Rubber Lining inside the tank that is very cracked and swollen, and the Corrosion that occurs on the metal surface of the tank under the Rubber Lining) Continue reading Vessel rubber lining inspection

Test Pressure vs MAWP (ASME VIII)

Hydrostatic Test Pressure vs MAWP of Section VIII Vessels;  An example of Hydrostatic Test Pressure compared to the MAWP of Pressure Vessel ( in the form of Shell & Tube Heat Exchanger) designed according to ASME Section VIII Div.1. What is Hydrostatic Test Pressure for Section VIII Vessels; The Hydrostatic Test of Pressure Vessel according to the ASME Section VIII Div.1 must be done at a pressure not less than 1.3 times of the Maximum Allowable Working Pressure (MAWP) of the Vessel multiplied by the Stress Ratio to compensate for the strength of the material. In case of use at high temperatures ( when Hydrotest is made at Ambient Temp.) , The Stress Ratio is the ratio of the Allowable Stress of the material to … Continue reading Test Pressure vs MAWP (ASME VIII)