Caustic(Sodium Hydroxide) corrosion problem

  • Thread starter snr.sr2006
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    Corrosion
In summary: Up to 110°C, yes, but it might be a bit dangerous to do the corrosion test in the lab. You could try heating the beaker up to the desired temperature and checking the temp. increase.
  • #1
snr.sr2006
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I am using castic as heating / Cooling media for the reactors in my lab. MOC of my reactor and pipeline is CS. Can anyone tell how to prevent / minimise this?
 
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  • #2
You might try adding a bit of sodium carbonate with the hydroxide. The carbonate will produce a passivating iron carbonate coating on the interior of the CS (carbon steel?) tubes.

Why such an exotic teat transfer fluid?
 
  • #3
Thank you sir,
Let me tell you in somewhat detail, we are using caustic in the reactors for the PVC process. Since the reaction is exothermic and controlled at around 105°C to 115°C, we can not use water, so we use this as heating / cooling media. Now I am observing the lines are getting punctured mostly near bends or in between. so in the first observation I doubt on Hot Caustic solution which is corrosive as all know. We are using 12 to 15 % concentration caustic.

As suggested by you we have to use Sodium carbonate with caustic . Can we use Calcium carbonate? and If yes then How much we have to add in my system where I am using 12% caustic solution? Thanks in advance.
 
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  • #4
Calcium carbonate won't do any good. It's not soluble enough in the NaOH solution. It sounds like you are getting some galvanic corrosion near the bends due to stress or the welds. You might try to increase the carbonate levels and perhaps think of entirely replacing the NaOH with the carbonate.

Have you ever sectioned a bend to see if scaling is a problem as well?
 
  • #5
I will open the line but it will take some time but once I do that definitely will give feedback to you. Now can Calcium carbonate / sodium carbonate will give temperatures upto 110°C. How can I test that in my lab? will there be any problem of dipostion in my reactor which will then reduce the heat transfer? Can it be very simple as by keeping in the beaker and heating it and checking how much temp. increases? In the same test I can try the corrosion test also. What do you suggest?
 

1. What is Caustic (Sodium Hydroxide) corrosion problem?

Caustic (Sodium Hydroxide) corrosion problem refers to the damage caused by the chemical reaction between sodium hydroxide and certain materials, leading to the degradation and weakening of the affected material. This can occur in various industries, such as manufacturing, oil and gas, and wastewater treatment.

2. What are the common materials affected by Caustic (Sodium Hydroxide) corrosion?

Some of the common materials affected by Caustic (Sodium Hydroxide) corrosion include metals, such as steel, aluminum, and copper, as well as plastics, rubber, and concrete. The severity and rate of corrosion may vary depending on the concentration and temperature of the sodium hydroxide solution.

3. What are the main causes of Caustic (Sodium Hydroxide) corrosion?

The main cause of Caustic (Sodium Hydroxide) corrosion is the alkaline nature of sodium hydroxide, which can react with certain materials and break down their chemical structure. Other factors that can contribute to corrosion include high temperatures, prolonged exposure, and the presence of other chemicals or impurities in the solution.

4. How can Caustic (Sodium Hydroxide) corrosion be prevented?

There are several ways to prevent Caustic (Sodium Hydroxide) corrosion, including using corrosion-resistant materials, such as stainless steel or plastics, in equipment and pipelines. It is also important to monitor and control the concentration and temperature of the sodium hydroxide solution. Regular maintenance and inspections can also help identify and address any potential corrosion issues.

5. What are the potential hazards of Caustic (Sodium Hydroxide) corrosion?

Caustic (Sodium Hydroxide) corrosion can have serious consequences, including equipment failure, leaks, and environmental contamination. It can also pose a safety risk to workers, as exposure to high concentrations of sodium hydroxide can cause burns, irritation, and other health hazards. Proper handling, storage, and disposal of sodium hydroxide are crucial in preventing these hazards.

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