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.

1 . A method of providing advisory controls for a desalter system, comprising:
 processing a crude oil blend in an oil refinery, wherein the crude oil blend creates an emulsion band;   utilizing a desalter system to desalt the crude oil blend;   continuously monitoring performance of the desalter system;   continuously monitoring position of the emulsion band;   controlling the emulsion band using chemicals; and   providing recommendations for maintaining optimal pressure drop at a mix valve of the desalter system.   
     
     
         2 . The method of  claim 1 , wherein the emulsion band comprises crude oil and water, positioned as a distinct layer between a water and crude oil interface. 
     
     
         3 . The method of  claim 2 , wherein the emulsion band is dynamic in position and size. 
     
     
         4 . The method of  claim 3 , wherein the chemicals used to control the emulsion band are demulsifiers. 
     
     
         5 . The method of  claim 4 , wherein the demulsifiers comprise oxyalkylated amines, alkylaryl sulfonic acid and salts thereof, oxyalkylated phenolic resins, polymeric amines, glycol resin esters, polyoxyalkylated glycol esters, fatty acid esters, oxyalkylated polyols, low molecular weight oxyalkylated resins, bisphenol glycol ethers and esters and polyoxyalkylene glycols. 
     
     
         6 . The method of  claim 5  further comprising adding the demulsifiers until point of inflection is reached. 
     
     
         7 . The method of  claim 1 , wherein an ultra-sound sensor is used to monitor position of the emulsion band. 
     
     
         8 . The method of  claim 7 , wherein the ultra-sound sensor measures the position, quality or size of the emulsion band. 
     
     
         9 . The method of  claim 8 , wherein a first principles based model is used to monitor performance of the desalter system. 
     
     
         10 . The method of  claim 9 , wherein the first principles based model utilizes geometry of the desalter system, physical properties of crude oil and water, and operating conditions of the desalter system. 
     
     
         11 . The method of  claim 10 , wherein a Model Predictive Controls utilizes the first principles based model to control the emulsion band using chemicals. 
     
     
         12 . The method of  claim 11 , wherein the Model Predictive Control can utilize performance measurements, salt removal, water removal, and oil content of brine to adjust model parameters. 
     
     
         13 . The method of  claim 12 , wherein the Model Predictive Controls doses the chemicals so that the sensed emulsion band is under control. 
     
     
         14 . The method of  claim 13 , wherein the Model Predictive Controls provides advisory solutions to users on effect of changing the mix valve delta pressure drop based on performance of the desalter system. 
     
     
         15 . The method of  claim 14 , wherein recommendations are provided to users based on effect variation in wash water flow rate and based on performance of the desalter system. 
     
     
         16 . The method of  claim 1 , further comprising: processing a new crude oil blend in the oil refinery; and recalculating the desalter system based on the new crude oil blend. 
     
     
         17 . The method of  claim 16 , further comprising: determining effectiveness of chemical treatment; and initiating appropriate corrective actions during upset conditions. 
     
     
         18 . The method of  claim 17 , wherein the chemical treatment comprises adding demulsifiers to keep position and size of the emulsion band under control. 
     
     
         19 . The method of  claim 18 , wherein advisory solutions and recommendations are provided to users when initiating appropriate corrective actions during upset conditions. 
     
     
         20 . The method of  claim 19 , wherein the advisory solutions are provided to users for changing the mix valve delta pressure drop based on performance of the desalter system.