Industrial cleaning knowledge popularization, teach you how to use pickling corrosion inhibitor correctly. Pickling corrosion inhibitor is used to slow down the corrosion of metal matrix by acid in metal pickling process and has good corrosion inhibition effect in various chemical pickling processes. When the process conditions and corrosion inhibitors are determined, there is still a problem of accurate use of corrosion inhibitors. Otherwise, even if the function is appropriate corrosion inhibitor, if not accurate use, also do not receive good results.
Accurate use of corrosion inhibitor is mainly reflected in the control of pickling conditions. It is right to say that after selecting the appropriate corrosion inhibitor according to the process parameters, the actual pickling should in turn limit the possible range of pickling process parameters according to the function of corrosion inhibitor.
For example, when pickling is determined to be carried out under the premise of 5%HCl and 50℃, the corrosion inhibition efficiency of the selected corrosion inhibitor for carbon steel tube is 98 ~ 99% at 40 ~ 60℃ and 4 ~ 7%HCl. Then, to ensure that the corrosion inhibition efficiency of 98 to 99% is indeed received, it is necessary to ensure that the acid concentration does not exceed 7% and the temperature does not exceed 60℃ during the entire pickling operation. This is not too difficult to do during normal pickling. But it is not so easy to be strict in the operation of acid feeding, acid mixing and pre-heating. Some necessary measures must be taken in process control. It is also necessary to note that “shall not exceed” here does not only refer to the data measured at the observation point and the data analyzed at the sampling point, but also refers to the whole pickling system including any local area and no specified parameters are exceeded at any moment.
Another important issue in the accurate use of corrosion inhibitors is inhibitor concentration. Any function of the inhibitor is manifested only after the inhibitor has reached a certain concentration. Therefore, to ensure the corrosion inhibition effect, it is not only to see how many tons of acid and how many kilograms of corrosion inhibitor, more important is to see whether the distribution of corrosion inhibitor is average. It is necessary to avoid the uneven phenomenon of high concentration of one local corrosion inhibitor and low concentration of others.
Corrosion inhibitor concentrations are often impossible to determine chemically. The control of its concentration is mainly guaranteed from the way of adding. The way of adding corrosion inhibitor should be different according to the function of choosing corrosion inhibitor. It can be added to the water in advance, or it can be added to the concentrated acid in advance or added to the corrosion inhibitor at the same time. Either way, it is necessary to make the corrosion inhibitor added at a rate proportional to the acid entering the boiler. In this way, when the whole boiler is full of acid, the corrosion inhibitor is equally distributed in the entire pickling system according to the designated amount. The addition of corrosion inhibitor can be manually added from the mouth of the acid tank, or injected into the pickling system with a metering pump and acid tube in parallel. Where there is a premise, it is better to use the latter way, so as to ensure the quality of corrosion inhibitor and save work safety
