Method for controlling a rectification column

Patent metadata

Field	Value
Publication number	US-11235260-B2
Application number	US-201716322990-A
Country	US
Kind code	B2
Filing date	Aug 1, 2017
Priority date	Aug 4, 2016
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

The present invention relates to a method of controlling a concentration of a first component of a rectification column for separating a binary mixture of the first component with a second component on the basis of temperature measurements, wherein a control path defined by temperature sensors (T3, T2, T6) arranged in the longitudinal direction of the column is linearized with the aid of an estimated temperature profile, wherein a real temperature profile T*(h), determined by means of the temperature sensors, is approximated by a function T(h) in dependence on a column height h, wherein the column id divided into two sections along the column height h and the function T(h) is defined section by section on the basis, in each case, of a logistical function.

First claim

The invention claimed is:

1. A method of controlling a concentration of at least one first component in a rectification column for separation of a binary mixture of the first component with a second component based on temperature measurements, the method comprising:
(a) linearizing a control zone defined by temperature sensors arranged in the longitudinal direction of the rectification column with the aid of an estimate of a temperature profile, and
(b) approximating a real temperature progression T*(h) determined by means of the temperature sensors by a function T(h) as a function of a column height h, wherein:
(i) the column is divided into two sections over the column height h, and
(ii) the function T(h) is defined in sections on the basis of one logistic function in each section.

2. The method of claim 1 , in which the logistic functions are formed on the basis of a logistic function of the following form:

f
⁡

(
x
)

=

e
x

1
+

e
x

.

3. The method of claim 1 , wherein:

T
⁡

(
h
)

=

{

T
ab

⁡

(
h
)

,

h
<

h
feed

T
v

⁡

(
h
)

,

h
≥

h
feed

where T ab (h) and T v (h) are defined on the basis of one logistic function each and h feed defines the column height at which a solution consisting of 40% by volume to 60% by volume of the first component and 40% by volume to 60% by volume of the second component is fed to the column.

4. The method of claim 3 , in which:

T
v

⁡

(
h
)

=

T

0
,
v

+

v
v

·

e

(

h
-

h

0
,
v

)

⁢

k
v

1
+

e

(

h
-

h

0
,
v

)

⁢

k
v

T
ab

⁡

(
h
)

=

T

0
,
ab

+

v
ab

·

e

(

Assignees

• Covestro Deutschland Ag

Inventors

• Schweigert Mathias
• Küpper Achim

Classifications

• B01D3/4211 Primary

  of columns · CPC title

• B01D3/4294

  Feed stream · CPC title

• G05D21/00

  Control of chemical or physico-chemical variables, e.g. pH value · CPC title

• G05B11/14

  in which the output signal represents a discontinuous function of the deviation from the desired value, i.e. discontinuous controllers (G05B11/26 takes precedence) · CPC title

• B01D3/425 Primary

  Head-, bottom- and feed stream · CPC title