Impact Study Of Atmospheric Tower Circulate Breakflow And Products Quality

Crude oil distillation unit was the first unit on refinery and consumed15%to17%energy of it. In this unit, the atmospheric tower, as an important component, made crude oil toproducts for downstream processes. Due to the characteristics of the crude oil distillationprocess, atmospheric tower had excess energy, and need to create refluxing to take awayenergy, especially the middle circulate breakflows, meanwhile adjusted product quality.Therefore, good atmospheric tower operation not only allow the unit to obtain high-qualityproduct, but also recycle as much useful energy, reduce energy consumption of refiningprocess. Therefore, influence of circulate breakflow and product quality was very important.This paper found the relationship of the product quality and circulate breakflow byapproximately linear refluxing equations on the atmospheric tower, and used it to optimizeoperations. The main contents of the article were following: presented approximately linearrefluxing equations by the atmospheric tower operating characteristics. The formula meanedthat, under certain conditions, the temperature variable, the load variable of the liquid andvapor of the column trays had a relatively linear relationship with circulate breakflows;through theoretical derivation, and process simulation software model to testify the formula.Experiments showed that, in addition to individual cases which had extreme circulatebreakflows, universal error of relationship were less than3%; under approximate linearformula and previous studies on product quality, this paper proposed relationship of productquality and circulate breakflows, and raise an empirical model and optimization method forquality of the atmospheric tower; established empirical models, and optimized circulatebreakflows to improve products quality in two actual cases.Case studies showed that the empirical model proposed in the article had good predictiveaccuracy of the plate temperature, gas and liquid load. More importantly, with the relationshipof product quality and circulate breakflows, the model could quickly and efficiently optimizedproduct quality by adjust circulate breakflows.