Ethylene furnace process and system

Patent metadata

Field	Value
Publication number	US-10655071-B2
Application number	US-201515314133-A
Country	US
Kind code	B2
Filing date	May 28, 2015
Priority date	May 28, 2014
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

Methods and systems for managing a decomposition process are disclosed. An example method can comprise estimating a coking rate for a process based on a coking model. The coking model can comprise a pyrolytic coking term and a catalytic coking term. An example method can comprise, performing at least a portion of the process, receiving a parameter for the process, and adjusting an operation of the process based on the parameter.

First claim

What is claimed is:

1. A method for estimating the coking rate in an ethane cracking furnace to produce ethylene comprising the steps of:
estimating a coking rate for the cracking process in the furnace based on a coking model, wherein the coking model comprises a pyrolytic coking term wherein pyrolytic coke is formed and a catalytic coking term wherein catalytic coke is formed;
performing at least a portion of the cracking process;
receiving a parameter for the process;
providing a concentration of ethylene (c ethylene ) and of a coking agent (c a *); and
adjusting an operation of the process based on the parameter;
wherein the parameter comprises at least one member selected from the group consisting of a tube metal temperature, and a pressure drop associated with a tube, wherein the catalytic coking term is based on a surface concentration of catalytically active sites;
wherein the catalytic coking term is based on the concentration of ethylene (c ethylene ) and the pyrolytic coking term is based on the concentration of coking agent (c a *);
wherein the coking rate (r coking (z)) is defined for the coking model as in equation (1)
τ coking ( z )= k c c a ·( z )+ k cat φ cat ( z ) c ethylene ( z ), zϵ[ 0, L]   (1)

wherein the surface concentration of catalytically active sites, C cat can change with time due to pyrolytic coke formation, as follows:

d
⁢

⁢

φ
cat

⁡

(
z
)

dt

=

-

k
c

⁢

c
a

·

(
z
)

⁢

φ
cat

⁡

(
z
)

,

z
∈

[

0
,
L

]

⁢

⁢

φ
cat

⁡

(
z
)

=

(

c
cat

c
cat
max

)

,

(
2
)

wherein C cat max is the maximum surface concentration of catalytically active sites and with the initial condition:
φ cat (z)=1, zϵ[0, L], t= 0.

2. The method of claim 1 , further comprising performing at least a portion of the process based on the adjusted operation of the process.

3. The method of claim 1 , wherein the operation is an anti-coking operation.

4. The method of claim 1 , wherein receiving the parameter for the process comprises monitoring in real-time the parameter for the process.

5. The method of claim 4 , wherein adjusting the operation comprises adjusting the process in real-time in response to the monitoring.

6. The method of claim 1 , wherein adjusting the operation comprises at least one step selected from the group consisting of a) modifying a time to at least one of end the process and interrupt the process, and b) scheduling a time to clean a tube implementing the process.

7. The method of claim 6 , wherein the adjusting of the operation comprises scheduling a time to clean a tube implementing the process.

8. A method for estimating the coking rate in a process to crack ethane to produce ethylene, comprising:
determining a first coking rate for the process based on a coking model, wherein the coking model comprises a pyrolytic coking term and a catalytic coking term;
determining a second coking rate of the process;
providing a concentration of ethylene (c ethylene ) and of a coking agent (c a *); and
adjusting a process or evaluating an operation based on a comparison of the first coking rate and the second coking rate; wherein determining the second coking rate of the process comprises monitoring in real-time a parameter for the process and determining the second coking rate based on the parameter or the coking model;
wherein adjusting the process comprises adjusting the process in real-time in response to the monitoring; and
wherein the parameter comprises at least one of a tube metal temperature, and a pressure drop associated with a tube, and wherein the catalytic coking term is based on a surface concentration of catalytically active sites;
wherein the catalytic term is based on the concentration of ethylene (C ethylene ) and the pyrolytic coking term is based on the concentration of coking agent (c a *);
wherein the coking rate (r coking (z)) is defined for the coking model as in equation (1)
τ coking ( z )= k c c a ·( z )+ k cat φ cat ( z ) c ethylene ( z ), zϵ[ 0, L]   (1)

wherein the surface concentration of catalytically active sites, Ccat can change with time due to pyrolytic coke formation, as follows:

Assignees

• Sabic Global Technologies Bv

Inventors

• Iliyas Abduljelil
• Saudagar Munawar
• Belfadhel Hatem

Classifications

• C10G9/36

  with heated gases or vapours · CPC title

• C10G75/00 Primary

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

• F27B19/04

  arranged for associated working · CPC title

• C10G9/206

  controlling or regulating the tube furnaces · CPC title

• C10G2300/4075

  Limiting deterioration of equipment · CPC title