High dry point of alkylated oils: analysis of influencing factors

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This post was last edited by Green Lotus on 2018-11-5 at 15:15. An analysis of the factors affecting the dry point of alkylated oil was conducted; in light of the fluctuations in the quality of products produced by the alkylation unit, the main influencing factors were identified through examination of the original operation records. Data sets 1 to 30 show that the factors having the greatest impact on the dry point of alkylated oil are mainly related to the content of isobutylene and isopentane in the feed, as well as aspects such as the purity of isopentane within the entire reaction system, the concentration of circulating acid, the reaction temperature, and the processing load； 1. Groups 1–4 of data (February 22–24, 2017) show that when the amount of olefins in the feed is kept low, and the concentrations of isobutylene, isopentane, and circulating acid remain essentially constant, as the purity of isobutane in the reaction system increases, the reaction temperature decreases, and the processing load is reduced (from 4 compressors to 3), the dry point drops. For every 2% increase in the purity of isobutane in the reaction system (i.e., the refrigerant), the reaction temperature decreases by approximately 1°C, and the dry point drops by 1°C. The minimum purity limit for isobutane in the reaction system is set at 75%, with a minimum of 70%; otherwise, the dry point will get out of control ； 2. A comparison of the data from groups 1-4 and 5-8 (January 7–9, 2017) shows that as the purity of isobutane in the reaction system and the concentration of circulating acid increase, the dry point decreases significantly; when the purity of isobutane is >80% and the concentration of circulating acid is >91%, the dry point drops by 3–7°C. 3. The data from groups 9-12 (May 7–9, 2018) and 13-16 (May 27–29, 2018) show that as the contents of isobutylene and isopentane in the feed increase, the dry point of the alkylated product rises. When the isobutylene content exceeds 2% and the isopentane content exceeds 0.5%, the dry point of the alkylated oil increases significantly; this leads to a decrease in acid concentration, an increase in acid consumption, more side reactions, and further rise in the dry point ； When isobutylene > 2%, isopentane > 1%, and the circulating acid concentration is 86%-88%, the overall effect is an increase in the dry point by 4-10°C. (The data sheet will not be sent.)