Should corrosion inhibitor or ammonia water be added to the oil and gas cooling system at the top of the catalytic fractionator?
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I would like to ask everyone: do you add corrosion inhibitors or ammonia water to the oil and gas stream at the top of your distillation towers? How is it added, and what is the effect?
This line is usually included in the design, but it’s hard to say in practice
We don’t pay attention to it at the moment; we keep the iron ion level below 2
The ammonia solution we used works quite well
Now, the tops of many units are modified to inject acidic water, which is fed in through the oil and gas outlet pipeline at the top of the tower. The effects vary significantly for high-sulfur or low-sulfur feedstocks.
What is the effect? We inject ammonia water; I would like to ask what happens when acidic water is injected into high-sulfur oil. What is the typical level of iron ions in that case, and vice versa?
These days, more acidic water is being used; acidic water can also become alkaline, and the results are good
For raw materials with high nitrogen content, the acidic water at the top of the tower is alkaline and sometimes has an ammonia smell. So either ammonia water or a corrosion inhibitor can be used, but in small amounts. However, for the air cooling of compressed rich gas, corrosion inhibitors can be added, which is effective; moreover, the wastewater produced is fed back to the inlet of the air cooler at the top of the large fractionation tower.
This is related to the sulfur content of the raw material. When Daqing oil is used, there is basically no serious corrosion even if it is not added, whereas with imported oil that is high in sulfur and acid, problems may arise within a month or so if it is not used.