关键词: K2CO3/Al2 O3, 固体碱, 酯化, 原油, 脱酸

Abstract: Developing esterification catalysts with high performance is considered to be a key factor to improve the efficiency of catalytic esterification. Compared with the conventional acidic esterification catalysts, the solid alkaline catalysts show better anti-poisoning property and higher stability. A series of alumina-supported K2CO3 catalyst is prepared by pore volume impregnation method and used in the esterification reaction to remove acid from crude oil. The property of catalysts is characterized by XRD and N2 adsorption-desorption. Hammett indicator and benzene carboxylic acid titration method are used to measure the basicity strength and basicity amount distribution on the
catalysts. The effects of K2CO3 content on catalysts’ property and deacidfication activity are investigated and the esterification reaction conditions are studied. It is shown that the poor dispersed multilayer K2CO3 crystallites are formed on the catalyst which contains 25% K2CO3, causing a great decrease of specific surface area and pore volume of catalyst. The total basicity amount (H–>9.3) and weak basicity amount (9.3increased with the increase of K2CO3 loading until it reaches 20%, and if the increase continues, it will lead to the decrease of basic sites. The results also indicated that the weak basic sites with 9.3major contribution to the catalyst’s deacidfication activity. The catalyst loaded with 20% K2CO3 has the greatest
amount of weak basic sites and thus the highest catalytic activity. It can remove 97.8% acid of Liaohe high acidity crude oil and the acid value of crude oil can be decreased from 11.17 mgKOH/g to 0.25 mgKOH/g under the optimal
reaction conditions of reaction temperature 200 ℃, reaction time 2 h, catalyst and glycol mass fraction 1% and 2%, respectively. Moreover, the K2CO3/Al2O3 catalyst shows good repeated-use performance.

Key words: K2CO3/Al2O3, solid alkaline, esterification, crude oil, deacidification