Operational excellence for Distillation Units and particularly for Crude Distillation Units is achieved by tight control of product quality which is usually estimated by inferential models. This article is focused on a novel approach leading to calculate an appropriate input to the inferential model strictly related to the characteristics of real feed to the column rectifying section where the separation of products occurs. The calculation simplicity based on usually available plant measurements is an additional feature of the proposed approach. This article introduces the definition of a novel curve characterizing hydrocarbon streams: the True Dew Point curve (TDP), whose name recalls the strong relationship with True Boiling Point curve (TBP). Inferential results obtained with the TDP curve have been performed adopting an approximation of the rectifying feed TDP curve with the assumption that any more accurate TDP curve description would give better results. Inferential validation has been carried out comparing the estimations with two different approaches: one based on model input derived from the crude feed TBP curve, assuming that is known and considering these results as benchmark, the other based on a pilot tray temperature (assuming available) as model input for each product. A general database has been built running rigorous simulation models of an atmospheric fractionator, with variations of most operating parameters affecting the distillation ASTM 95% quality chosen as product specification. This article suggests the way to solve problems deriving from high nonlinearity of feed TBP curves, showing the application of TDP methodology to a vacuum fractionator. An application to real laboratory and plant data of atmospheric fractionator is also shown.

中文翻译：

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基于真实露点曲线的在线产品质量估计器用于原油蒸馏装置的控制

蒸馏装置，特别是原油蒸馏装置的卓越运营是通过对产品质量的严格控制来实现的，这通常由推论模型估计。本文重点介绍一种新方法，该方法可计算推理模型的适当输入，该输入与发生产品分离的塔精馏段的实际进料特性严格相关。基于通常可用的工厂测量的计算简单性是所提出方法的附加特征。本文介绍了表征烃流的新型曲线的定义：真露点曲线 (TDP)，其名称让人想起与真沸点曲线 (TBP) 的密切关系。使用 TDP 曲线获得的推论结果已采用近似修正进料TDP 曲线，假设任何更准确的 TDP 曲线描述都会给出更好的结果。已经进行了推论验证，将估计与两种不同的方法进行了比较：一种基于来自原油进料的模型输入TBP 曲线，假设已知并考虑这些结果作为基准，另一个基于试验塔盘温度（假设可用）作为每个产品的模型输入。建立了一个通用数据库，运行大气分馏器的严格模拟模型，大多数操作参数的变化影响了蒸馏 ASTM 95% 的质量，被选为产品规格。本文提出了解决由进料 TBP 曲线的高度非线性引起的问题的方法，展示了 TDP 方法在真空分馏器中的应用。还展示了大气分馏器在实际实验室和工厂数据中的应用。