The issue of neutralizing corrosion inhibitors
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There is such a by-product: a mixture of methylmorpholine, ethylmorpholine, and morpholine. Methylmorpholine 21.6%, ethylmorpholine 76%, morpholine 1%. Alkali value: 250 mg HCl/g; pH (1% aqueous solution) ≥ 10. Its corrosion inhibition efficiency is higher than that of triethanolamine, and it exhibits satisfactory neutralizing and corrosion-inhibiting properties. Since my company is engaged in the synthesis of fine chemicals, my knowledge of the petrochemical industry is only superficial; I would like to seek the insights of industry professionals to discuss this product together. If you have any suggestions, feel free to leave a message or call me at 13716358245, Dong Lei.
I personally don’t think mixed amines, as you mentioned, are suitable as neutralizing and corrosion-inhibiting agents in refineries. Firstly, it is clearly not very meaningful to choose only triethanolamine for comparison in terms of both neutralization capacity and corrosion inhibition rate. Secondly, there is a lot to consider when selecting the components of neutralizing and corrosion-inhibiting agents used in refineries, such as the solubility, volatility, boiling point, and salt-forming properties of the neutralizing agents, as well as the appropriate operating temperature for the corrosion-inhibiting components, their film-forming capabilities, and their tendency to emulsify. I have been in contact with morpholine waste (which is essentially the same as the mixed amine you mentioned); when its solution in water is left standing for a while, crystals or scale should form on the inner walls of the container.
Thank you for giving me advice. Actually, this doesn’t count as morpholine waste either, because our main product is manufactured using a continuous process, and the components of the by-products are stable; their boiling point is below 130 degrees Celsius. The mixed amines you mentioned, which appear to crystallize, likely contain large-molecule morpholine substances, such as long-chain morpholines or compounds that contain more than one morpholine ring. The mixture I’m talking about can be mixed with water in any proportion.
Have you observed or learned about the properties of the salts they form with hydrochloric acid?
I’m not really sure what specific reactions occurred, as I know very little about the petrochemical industry. Some manufacturers used it in the past, for neutralizing and corrosion-inhibiting purposes; it was used for about half a year, with a monthly purchase volume of 10 tons. It was stopped being used later because of the strong ammonia smell emitted by this product, and it seems that the salts formed do not crystallize. As far as I know, ethylenediamine is commonly used as a neutralizing agent in neutralizing corrosion inhibitors; ethylenediamine also has a rather strong odor, haha. Moreover, morpholine also possesses decent corrosion-inhibiting properties. The proportions of the various components in this by-product remain quite stable; each component alone accounts for around 20,000 units. However, this mixture is essentially an azeotrope, making separation difficult. Do you have any other better ideas? Thank you.