Advisory controls of desalter system

Abstract

The present invention concerns a method of providing advisory controls for a desalter system. The method allows a user to continuously monitor performance of the desalter system, to continuously monitor position of the emulsion band (or rag layer), to control the emulsion band using demulsifiers, and to recommend to users how to maintain optimal pressure drop at the mix valve of the desalter system. This is achieved by using a first principles based model combined with an ultra-sound sensor. The ultra-sound sensor measures the position, quality and size of the emulsion band. The first principles based model takes into account the geometry of the desalter system, physical properties of the crude oil and water, as well as the operating conditions. Thus, the method provides users with sensing of an emulsion layer through ultrasound measurements and also gives recommendations on appropriate corrective actions to be initiated during upsets.

Description

FIELD OF INVENTION[0001]The present invention pertains to a method of providing advisory controls for a desalter system. More particularly, the method continuously monitors performance of the desalter system, continuously monitors position of the emulsion band, controls the emulsion band using chemicals and provides recommendations for maintaining optimal pressure drop at the mix valve.BACKGROUND OF THE INVENTION[0002]Desalting is typically the first operation in oil refineries. Crude oil that is processed without desalting is detrimental to the refinery assets, leading to severe corrosion problems. The desalter system removes the majority of salts in the crude oil by injecting water into the system. Because of the higher solubility in water, salts move from the crude oil to the water phase. Thus, desalter systems are typically large gravity settling tanks that provide enough residence time for both the water and the crude oil to settle. Usually density of water is higher than that ...

AI Technical Summary

Problems solved by technology

Crude oil that is processed without desalting is detrimental to the refinery assets, leading to severe corrosion problems.

Typically, these emulsion bands can cause oil refiners to run less than optimum wash water rates and low mix valve pressure drops, which reduces its efficiency for salt and sediment removal.

Excessive growth of these emulsion bands can shorten the operational lifespan of the electrical grids in the desalter system, thus bringing the entire refinery operations to a halt.

Furthermore, operation of the desalter system is difficult and requires an expert with vast experience to make the right corrective decision.

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