Methods for mitigating fouling of process equipment

Patent metadata

Field	Value
Publication number	US-9404847-B2
Application number	US-201113294300-A
Country	US
Kind code	B2
Filing date	Nov 11, 2011
Priority date	Nov 17, 2010
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

Methods for determining the fouling propensity of a hydrocarbon stream and for reducing fouling are provided. In one method, the fouling propensity of a hydrocarbon stream is determined by obtaining a parameter indicative of the fouling propensity by a regression of a series of temperature measurements data for the hydrocarbon stream exiting a test unit. In another method, an effective minimal amount of an antifoulant is added to a hydrocarbon stream to reduce fouling, where the amount of the antifoulant is determined based on the fouling propensity of the hydrocarbon stream.

First claim

The invention claimed is:

1. A method for determining a propensity of a hydrocarbon stream to foul process equipment, comprising:
introducing a hydrocarbon stream to a test unit, the test unit comprising a chamber defined by a wall for the hydrocarbon to flow through, an inlet for feeding the hydrocarbon into the chamber, an outlet for discharging the hydrocarbon stream, and a heating element maintained at a substantially constant surface temperature T c and disposed within the chamber for heating the hydrocarbon flowing across the surface of the heating element to cause fouling;
obtaining a series of temperature measurements over time of the hydrocarbon stream exiting the outlet of the test unit, including:
measuring an initial temperature T 1 of the hydrocarbon exiting from the outlet when the heating element is essentially free from fouling;
measuring the temperature T(t) of the hydrocarbon exiting from the outlet successively at predetermined time intervals subsequent to measuring the initial temperature T 1 , where t denotes time;

determining a parameter indicative of a propensity of the hydrocarbon to foul process equipment by a regression of ΔT(t) according to the equation:

Δ
⁢

⁢

T
⁡

(
t
)

=

1
-

[

1
+

k
⁡

(

ut
/
L

-
1

)

(

1
-
k

)

⁢

(

1
+

kut
/
L

)

]

1
/

(
kq
)

where ΔT(t) is a time-dependent quantity which is defined as ΔT(t)=(T(t)−T 1 )/(T c −T 1 ), k is the parameter to be determined, t is time, u is the average velocity of the hydrocarbon in the chamber of the test unit, L is the length of the section of the chamber where the hydrocarbon is heated, and q is a factor relating to heat transfer.

2. The method of claim 1 , wherein the heating element of the test unit is a heated rod.

3. The method of claim 2 , wherein q is a factor relating to heat transfer capacity of the system comprising the test unit wall, the heated rod, and the hydrocarbon stream.

4. The method of claim 2 , wherein the constant surface temperature of the heated rod is in a range of from about 300° C. to about 500° C.

5. The method of claim 1 , wherein the chamber of the test unit is tubular, and wherein the inlet and the outlet are disposed near the opposing ends of the tubular chamber.

6. The method of claim 1 , wherein the hydrocarbon is maintained at a constant predetermined flow rate in the chamber of test unit.

7. The method of claim 1 , wherein the hydrocarbon is at least one of a crude oil, a blend of crude oils, or a refinery process stream.

8. A method for reducing fouling of a hydrocarbon stream, comprising
obtaining a parameter indicative of the propensity of the hydrocarbon to cause fouling by performing the method of claim 1 ,
determining an effective minimal amount of an antifoulant relative to the amount of hydrocarbon to be processed based on the parameter obtained;
adding the determined amount of the antifoulant to the hydrocarbon to reduce fouling.

9. A method for selecting a first hydrocarbon for blending with at least one second hydrocarbon for the purpose of reduce fouling, comprising
obtaining a parameter indicative of the propensity of a mixture of the first hydrocarbon and the at least one second hydrocarbon to cause fouling by performing the method of claim 1 , and
based on the parameter obtained, determining whether to select the first hydrocarbon to blend with the at least one second hydrocarbon for reduce fouling.

10. A method for selecting crude oils to form a suitable oil blend for processing in for the purpose of reduce fouling, comprising
forming a plurality of oil blends by mixing at least two different crude oils;
obtaining a parameter indicative of the propensity of each of the oil blends to cause fouling by performing the method of claim 1 ; and
selecting at least one oil blend for processing based on the obtained parameter of the oil blend.

11. A method for determining whether to purchase a hydrocarbon, comprising
obtaining a parameter indicative of the propensity of the hydrocarbon to cause fouling by performing the method of claim 1 , and
based on the parameter obtained, determining whether to purchase the hydrocarbon.

Assignees

• Ho Teh C
• Brons Glen B
• Exxonmobil Res & Eng Co

Inventors

• Ho Teh C
• Brons Glen B

Classifications

• C10G75/00

  Inhibiting corrosion or fouling in apparatus for treatment or conversion of hydrocarbon oils, in general (C10G7/10, C10G9/16 take precedence) · CPC title

• C10G2300/1033

  Oil well production fluids · CPC title

• G01N17/008 Primary

  Monitoring fouling · CPC title

• C10G2300/4075

  Limiting deterioration of equipment · CPC title

• G01N25/18

  by investigating thermal conductivity (by calorimetry G01N25/20; by measuring change of resistance of an electrically-heated body G01N27/18) · CPC title