We already know that an oil or petroleum refinery is a place where natural, raw oil is processed into refined products like petroleum, gasoline, heating oil, diesel fuel, kerosene, asphalt base and liquefied petroleum gas.
All these involve a lot of processes, and hence the refinery is somewhat similar to that of a chemical plant. All the crude oil feedstock that people talk about are got from oil production plants. An oil depot or a tank farm is usually seen near these oil plants that store liquid products that are produced.
The management of these sectors are very important in our world today. But the real bad story about these industries is when they are affected by corrosion and the expenditure caused to rectify it. In all places around the world, the industry of oil and gas does its level best in running these refineries as efficiently and trouble free as possible to reduce costs in this sector. One cankerous factor that is eating up these industries is corrosion. Corrosion is seen lining the oil plants that occur during hydrocarbon refining process. Corrosion which is commonly said to be the break down of a metal into its atomic form due to chemical reactions with its surroundings.
The effect of corrosion in an oil industry leads to the failure of parts which in turn leads to shut down, again to avoid this effect the plant has to be shut down to clean the facility. The amount spent in the cleaning and adverse effects of corrosion on a year amounts to US$ 3.7 billion. Well, this is a large sum and could be put to use in so many other ways, if only we could avoid the effects of corrosion.
There are various ways and reasons for the occurrence of corrosion. By knowing the causes we could come to a conclusion on the prevention of the occurrence.
Some reasons for the occurrence of corrosion in Oil and Gas Industries:
- are water droplets that cause pitting corrosion
- the steel becomes brittle from the exposure of heat and impurities from hydrogen
- and sulphide attack causing stress corrosion
Some of the ways adapted today to overcome the effects of corrosion are:
- Use of certain types of metal in certain areas of the plant to facilitate the plant to be longstanding inspite of the effects of corrosion
- For example, carbon steel is used for 80% of plant requirements as it is cost efficient and withstands most forms of corrosion due to hydrocarbon impurities below a temperature of 205 degree celsius. But as it is not able to resist other chemicals and environments, it is not used every where
- Other kinds of metals used are, low alloys of steel containing chromium and molybdenum, and stainless steel containing high concentrations of chromium for excessively corrosive environments
- Tougher metals like nickel, titanium, and copper alloys are used for the most corrosive areas of the plant which are mostly exposed to the highest of temperatures and the most corrosive of chemicals
Since, of late, with the increase in knowledge in the field gained over the years, it has become a lot easier and more effective in fighting the occurrence or corrosion. Some effective ways in preventing corrosion would be monitoring and preventing the occurrence of these effects even before they occur. "How do I do this" may be the question on your mind.
Monitoring is done both on-line and off-line. Offline monitoring refers to the monitoring of the effects of corrosion after it has happened and is usually identified while doing maintenance. Of course this isn't the most effective way of saving the plant but, this was used in older times. It used to be considered as a step taken that is better late than never. Today on-line system has evolved to make it more effective in solving problem before it gets worse.
Some of the methods of on-line corrosion monitoring are:
- Linear polarization resistance
- Electrochemical noise
- Electrical resistance
Previously, the processing of corrosion on-line seemed to be very slow and the details
given weren't enough to fill in the criteria required besides the data collected was not always accurate.
However, with the improvement in science we have newer technologies that give data twice as much as they used to be in the past and specific in their accuracy. This kind of assessment is known as real-time monitoring. This enables engineers to prevent and control corrosion and also enable better output by the plant. Any plants that have on-line corrosion information with accurate real time measurements help to detect and reduce high corrosion rates. These kind of technology advancements enable engineers to prevent and protect the plant by management systems called predictive management.
For more information about Corrosion and how to prevent it, contact us via our website at www.leopad.com
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