Technical paper
Neutralization Of Heat Stable Salts Revisited
Neutralization with caustic in amine systems has long been a debated topic and there is no shortage of experts weighing in on the pros and cons. This paper will revisit the historical practice of intentionally adding caustic to amine with the purpose of improving performance and reducing corrosion by "neutralizing" Heat Stable Amine Salts (HSAS) which have accumulated in the amine. The paper will briefly cover introductory concepts including electrolyte reactions, corrosion reactions, chelation, and the relationship between soluble iron and corrosion rate. A series of simulations will be used to demonstrate the effects of heat stable salts on the ionic speciation of amine, how adding NaOH affects the speciation, and what happens when too much NaOH is added to an amine system. Plant data from several amine units will be presented to show the effect of neutralization on soluble iron concentration as well as the impact of overneutralization on lean loading We will also use simulations to explore other relevant topics including the impact of neutralization on ionic strength / activity coefficients, and on potential volatility of HSS species such as acetate and formate in the regenerator reboiler.
Neutralization with caustic in amine systems has long been a debated topic and there is no shortage of experts weighing in on the pros and cons. This paper will revisit the historical practice of intentionally adding caustic to amine with the purpose of improving performance and reducing corrosion by “neutralizing” Heat Stable Amine Salts (HSAS) which have accumulated in the amine. The paper will briefly cover introductory concepts including electrolyte reactions, corrosion reactions, chelation, and the relationship between soluble iron and corrosion rate. A series of simulations will be used to demonstrate the effects of heat stable salts on the ionic speciation of amine, how adding NaOH affects the speciation, and what happens when too much NaOH is added to an amine system. Plant data from several amine units will be presented to show the effect of neutralization on soluble iron concentration as well as the impact of overneutralization on lean loading We will also use simulations to explore other relevant topics including the impact of neutralization on ionic strength / activity coefficients, and on potential volatility of HSS species such as acetate and formate in the regenerator reboiler.