how to develop dissimilar metal or galvanic corrosion prevention

what is dissimilar metal or galvanic corrosion prevention? Corrosion is a process of damage to a material due to environmental influences. This is a natural process in metals. Corrosion in metals and equipment in the oil and gas industry results in financial losses, pollutes the environment and can endanger human safety. Engineers and scientists do a lot of research on corrosion to prevent and control the corrosion rates. On this occasion, we will discuss Galvanic Corrosion or known as dissimilar metal corrosion. This corrosion occurs when 2 different metal or alloy metals in the same environment and interconnected. This corrosion occurs because of the potential difference between the metals so that one metal functions as the anode and the other metal functions as the cathode. The principle of galvanic corrosion is the same as the electro-chemical principle of electrodes (cathodes and anodes), electrolytes and electric current. Metal that functions as an anode is a metal which before being connected is more active or has a more negative corrosion potential. At the anode, corrosion will occur oxidation reaction or dissolution reaction. Whereas at the cathode there is a metal reduction reaction. Galvanic series is a list of the value of corrosion[…]

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CO2 removal from Natural gas in Ammonia Plant

CO2 removal unit in Ammonia Plant The raw material for the ammonia plant is natural gas. but unfortunately, many gas wells contain CO2 so that CO2 gas is very disturbing the process of making ammonia. In general, CO2 gas is discharged at the front of a factory or known as the front end process. Natural Gas will enter the CO2 removal unit. in this unit, an MDEA liquid will remove the CO2 gas from the natural gas stream. In general, there are 2 high vessels or columns which are the core part of this CO2 removal unit. On the left side, that is yellow is a CO2 absorber vessel. The function of this vessel is to capture or absorb CO2 gas from Natural Gas then CO2 gas will be carried by MDEA solution. MDEA solution which is rich in CO2 gas is channeled to the green right vessel. Here, CO2 gas will be released or separated from the MDEA solution. corrosion problem in CO2 removal unit there are some common corrosion problem in this CO2 removal unit inside the equipment and outside the equipment. CO2 gas is corrosive and erosive. This will create corrosion-erosion in piping especially in the elbow area[…]

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what is wet corrosion in oil and gas industry?

wet corrosion There are many ways to classify corrosion. However, in general, corrosion is divided into 3 major groups namely Wet corrosion, Dry corrosion, and biological corrosion. Wet corrosion, as the name implies, occurs only in the presence of an aqueous solution or an electrolyte. Dry corrosion or dry corrosion occurs when there is no fluid present or temperature above the dew point of the environment. Biological corrosion or biological corrosion is a specific type of wet corrosion that occurs in the presence of living organisms. sometimes wet corrosion is named as aqueous corrosion. Wet corrosion is an electrochemical process, and electrochemical reactions are used to explain it. Wet corrosion, as the name implies, occurs only in the presence of an aqueous solution (including condensation of moisture) or electrolyte and is the most common type of corrosion. Wet corrosion can be further categorized by the appearance of rusty metals : a. Uniform Corrosion b. Galvanic Corrosion c. Crevice Corrosion d. Pitting e. Intergranular Corrosion f. Selective Dealloying g. Erosion corrosion h. Stress Corrosion Cracking (SCC) Metals corrode through simultaneous oxidation and reduction reactions. The oxidation reaction generates electrons and places the ions in the solution. This reaction occurs at the[…]

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what is Stress corrosion cracking ?

Stress Corrosion cracking (SCC) this phenomenon can be defined as material cracking due to the combined effect of static stress and corrosion. The stress involved can be residual stress and actual stress from an external load. The corrosion that occurs is generally very localized. Localized corrosion on the surface of the material usually acts as a stress raiser or stress concentrator. This corrosive cracking can be either transgranular or intergranular cracking depending on the type of alloy, metallurgical and environmental conditions. there are 3 main causes that determine the occurrence of Stress Corrosion Cracking are: Tensile stress. This tensile stress can be a residual stress that occurs due to welding or metal forming and can be a real stress due to the workload received by the material. For example, a pipeline or pressure vessel that is operated with internal pressure. Temperature. In general, cases of Stress Corrosion Cracking occur at temperatures > 60 C The availability of certain ions, such as Chloride (Cl) ions. Until recently, engineers still have difficulty determining definite limits on the minimum limits for Stress Corrosion Cracking  triggers In general, Stress corrosion cracking resistant materials are stainless steel duplex or super-ferritic type. avoiding residual stress to[…]

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