Online zeta-potential measurements for optimization of emulsion breaker dosage in ethylene plants

Patent metadata

Field	Value
Publication number	US-2019185763-A1
Application number	US-201716328092-A
Country	US
Kind code	A1
Filing date	Aug 22, 2017
Priority date	Aug 23, 2016
Publication date	Jun 20, 2019
Grant date	—

Abstract

A method for treating an emulsion emanating from a quenching process in production of ethylene that includes online monitoring of zeta potential of the hydrocarbon/water emulsion in a quench water tower and/or a quench water loop. In response to the online monitoring of zeta potential, the method changes the amount of demulsifier being added to the hydrocarbon/water emulsion such that the amount of demulsifier is effective in breaking the emulsion.

First claim

1 . A method for treating an emulsion emanating from a quenching process in production of ethylene, the method comprising:
adding a demulsifier to a hydrocarbon/water emulsion in a quench water tower and/or a quench water loop in use for ethylene production; online monitoring of zeta potential of the hydrocarbon/water emulsion in the quench water tower and/or the quench water loop; and in response to the online monitoring of zeta potential, changing the amount of demulsifier being added to the hydrocarbon/water emulsion such that the amount of demulsifier is effective in breaking the emulsion.

2 . The method of claim 1 , wherein the amount of demulsifier is changed so that the zeta potential of the emulsion is within a range of −30 to +30 mV.

3 . The method of claim 1 , wherein the amount of demulsifier is changed so that the zeta potential of the emulsion is within a range of −5 to +5 mV.

4 . The method of claim 1 , further comprising:
monitoring of one or more physicochemical parameters of a hydrocarbon stream flowing into the quench water tower.

5 . The method of claim 4 , wherein the one or more physicochemical parameters is selected from the list consisting of: boiling point, critical point, surface tension, and vapor pressure.

6 . The method of claim 4 , further comprising:
in response to the monitoring of the one or more physicochemical parameters and the online monitoring of zeta potential, changing the amount of demulsifier being added to the hydrocarbon/water emulsion such that the amount of demulsifier is effective in breaking the emulsion.

7 . The method of claim 6 , wherein the amount of demulsifier being changed is changed so that the zeta potential of the emulsion is within a range of −30 to +30 mV.

8 . The method of claim 6 , wherein the amount of demulsifier is changed so that the zeta potential of the emulsion is within a range of −5 to +5 mV.

9 . The method of claim 1 , wherein the demulsifier is added at a point in the quench water tower and/or the quench water loop such that the demulsifier is effective in breaking the hydrocarbon/water emulsion in the quench water tower and/or the quench water loop.

10 . The method of claim 1 , wherein the demulsifier comprises a cationic demulsifier.

11 . A method for treating an emulsion emanating from a quenching process in production of ethylene, the method comprising:
adding a first demulsifier to a hydrocarbon/water emulsion in a quench water tower and/or a quench water loop in use for ethylene production; online monitoring of zeta potential of the hydrocarbon/water emulsion in the quench water tower and/or quench water loop; and in response to the online monitoring of zeta potential of the hydrocarbon/water emulsion, changing the amount of the first demulsifier being added to the hydrocarbon/water emulsion in the quench water tower and/or quench water loop; flowing effluent from the quench water tower and/or the quench water loop to a quench water settler; online monitoring of zeta potential of the effluent from the quench water tower and/or the quench water loop; adding a second demulsifier to the effluent from the quench water tower and/or the quench water loop; online monitoring of zeta potential of the effluent from the quench water tower and/or the quench water loop; and in response to the online monitoring of zeta potential of the effluent, changing the amount of the second demulsifier being added to the effluent from the quench water tower and/or quench water loop.

12 . The method of claim 11 , wherein the amount of the first demulsifier and the second demulsifier are changed so that the zeta potential of the hydrocarbon/water emulsion in the quench water tower and/or quench water loop and the zeta potential of the effluent from the quench water tower and/or the quench water loop are within a range of −30-+30 mV.

13 . The method of claim 11 , wherein the amount of the first demulsifier and the second demulsifier are changed so that the zeta potential of the hydrocarbon/water emulsion in the quench water tower and/or the quench water loop and the zeta potential of the effluent from the quench water tower and/or the quench water loop are within a range of −5 to +5 mV.

14 . The method of claim 11 , wherein the amount of demulsifier is changed so that the zeta potential of the emulsion is within a range of −5 to +5 mV.

15 . The method of claim 11 , wherein the first demulsifier is added at a point in the quench water tower and/or the quench water loop such that the demulsifier is effective in breaking the hydrocarbon/water emulsion in the quench water tower and/or the quench water loop.

16 . The method of claim 11 , wherein the second demulsifier is added to the effluent from the quench water tower and/or quench water loop in the quench water settler.

17 . The method of claim 11 , wherein the second demulsifier is added to the effluent from the quench water tower and/or the quench water loop before it is fed to the quench water settler.

18 . The method of claim 11 , wherein at least one of the first demulsifier and second demulsifier comprises a cationic demulsifier.

19 . The method of claim 11 , wherein the first demulsifier and second demulsifier are different.

20 . The method of claim 11 , wherein the first demulsifier and second demulsifier are same.

Assignees

• Sabic Global Technologies Bv

Inventors

• Robson Ian
• Cuoq Fabrice

Classifications

• C02F1/40

  Devices for separating or removing fatty or oily substances or similar floating material (cleaning or keeping clear the surface of open water from oil or like materials E02B15/04; devices in sewers for separating liquid or solid substances from sewage E03F5/14, e.g. for use in drains leading to the sewer E03F5/16) · CPC title

• C10G2300/80

  Additives · CPC title

• C07C7/20

  Use of additives, e.g. for stabilisation · CPC title

• C02F2101/325

  Emulsions · CPC title

• C10G75/04

  by addition of antifouling agents · CPC title