Development of continuous online salt-in-crude analyzer

Patent metadata

Field	Value
Publication number	US-9512370-B2
Application number	US-201314077389-A
Country	US
Kind code	B2
Filing date	Nov 12, 2013
Priority date	Nov 12, 2012
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

The present invention relates to online analysis of crude oil from desalting processes. Online analysis of the crude oil that has been desalted will allow for real time adjustments to process operating parameters such that the salt concentration of the crude oil is maintained within acceptable parameters. This online analysis can yield a more efficient process, reduce energy consumption of the desalting process, and maintain corrosion rates within acceptable limits.

First claim

What is claimed is:

1. A process for monitoring salinity of a dry crude stream in a crude oil desalting process, the process comprising the steps of:
feeding, to a wet crude stream or a recycled water stream, at least one emulsion breaking chemical using an emulsion breaking chemical injection system having a predetermined range of operating conditions and feeding, to the wet crude stream, the recycled water stream using at least one recycled water pump having a predetermined range of operating conditions to produce an enhanced wet crude stream including water from the recycled water stream and the at least one emulsion breaking chemical, wherein the wet crude stream is fed to the crude oil desalting process by a wet crude stream pump;
feeding the enhanced wet crude stream to a first mixing apparatus having a predetermined range of operating conditions to produce a mixed wet crude stream;
feeding the mixed wet crude stream to a dehydrator vessel having a predetermined range of operating conditions to produce a reduced water content crude stream and a waste water stream;
feeding the waste water stream using at least one waste water stream pump having a predetermined range of operating conditions to a waste water facility;
feeding a wash water stream using at least one wash water pump having a predetermined range of operating conditions to the reduced water content crude stream to produce a hydrated crude stream;
feeding the hydrated crude stream to a second mixing apparatus having a predetermined range of operating conditions to produce a mixed hydrated crude stream;
feeding the mixed hydrated crude stream to a desalter vessel having a predetermined range of operating conditions to produce a dry crude stream and the recycled water stream;
feeding the dry crude stream to a first continuous online analyzing unit for determining basic sediment and water (BSW) real time data of the dry crude stream, wherein the first continuous online analyzing unit is in communication with an online analyzer and provides the BSW real time data to the online analyzer;
feeding the recycled water stream to a second continuous online analyzing unit for determining total dissolved solids (TDS) real time data of the recycled water stream from the desalter vessel, wherein the second continuous online analyzing unit is in communication with the online analyzer and provides the TDS real time data to the online analyzer;
determining, by the online analyzer, salt concentration real time data of the dry crude stream based on a predetermined correlation of BSW real time data and TDS real time data, wherein the online analyzer is in communication with a multivariable controller and provides the salt concentration real time data to the multivariable controller;
assessing, by the multivariable controller, operating parameters of any of the wet crude stream pump, recycled water pump, emulsion breaking chemical injection system, first mixing apparatus, dehydrator vessel, waste water stream pump, wash water pump, second mixing apparatus, and desalter vessel; and
adjusting, by the multivariable controller, one or more of the operating parameters to maintain the salt concentration real time data within a predetermined range to minimize power usage of the crude oil desalting process, wherein the operating parameters are adjusted when the salt concentration data is outside the predetermined range and the operating parameters are adjusted within the predetermined range of operating conditions for the respective operating parameters.

2. The process of claim 1 wherein the predetermined range of the salt concentration in the dry crude stream is less than 10 lb/1000 barrels.

3. The process of claim 1 wherein at least one emulsion breaking chemical is fed to the wash water stream using a second emulsion breaking chemical injection system.

4. The process of claim 1 wherein the at least one wash water pump is operated within the predetermined range of operating conditions at a lowest level of flow required to maintain the salt concentration in the dry crude stream at less than 10 lb/1000 barrels.

5. The process of claim 1 wherein the at least one emulsion breaking chemical is injected using the emulsion breaking chemical injection system at a lowest injection rate required to maintain the salt concentration in the dry crude stream at less than 10 lb/1000 barrels.

6. The process of claim 5 wherein the injection rate is such that it results in a concentration of emulsion breaking chemical of 3-10 ppm of the mixed wet crude.

7. The process of claim 1 wherein the first mixing apparatus is operated within the predetermined range of operating conditions at a lowest mixing efficiency and the least amount of time required to maintain the salt concentration in the dry crude stream at less than 10 lb/1000 barrels.

8. The process of claim 1 wherein the dehydrator vessel is operated within the predetermined range of operating conditions at a lowest level of energy consumption required to maintain the salt concentration in the dry crude stream at less than 10 lb/1000 barrels.

9. The process of claim 1 wherein the at least one waste water stream pump is operated within the predetermined range of operating conditions at a lowest level of flow required to maintain the salt concentration in the dry crude stream at less than 10 lb/1000 barrels.

10. The process of claim 1 wherein the at least one recycled water pump is operated within the predetermined range of operating conditions at a lowest level of flow required to maintain the salt concentration in the dry crude stream at less than 10 lb/1000 barrels.

11. The process of claim 1 wherein the wet crude stream pump is operated within the predetermined range of operating conditions at a lowest level of flow required to maintain the salt concentration in the dry crude stream at less than 10 lb/1000 barrels.

12. The process of claim 1 wherein the second mixing apparatus is operated within the predetermined range of operating conditions at a lowest mixing efficiency and the least amount of time required to maintain the salt concentration in the dry crude stream at less than 10 lb/1000 barrels.

13. The process of claim 1 wherein the desalter vessel is operated within the predetermined range of operating conditions at a lowest level of energy consumption required to maintain the salt concentration in the dry crude stream at less than 10 lb/1000 barrels.

14. The process of claim 1 wherein the desalter vessel is operated within the predetermined range of operating conditions at a temperature of between 50-150° C.

15. The process of claim 1 wherein the multivariable controller adjusts the operating parameters within the predetermined range of operating conditions of the wet crude stream pump, recycled water pump, emulsion breaking chemical injection system, first mixing apparatus, dehydrator vessel, waste water stream pump, wash water pump, second mixing apparatus, and desalter vessel, such that the energy consumption of the process is at a minimum level required to maintain a salt concentration in the dry crude stream of less than 10 lb/1000 barrels.

16. The process of claim 1 wherein the BSW in the dry crude stream is less than 0.2% by volume of said dry crude steam.

Assignees

• Saudi Arabian Oil Co

Inventors

• Soliman Mohamed Ahmed A

Classifications

• C10G2300/205

  Metal content · CPC title

• C10G33/08 Primary

  Controlling or regulating · CPC title

• C10G31/08

  by treating with water · CPC title

• C10G33/04

  with chemical means · CPC title