Hydrocarbon Processing - November 2022 - 36
Process Optimization
The calculated control valve output to
the respective flow control valve (CVOP
= actual level (LA
target output (TOP
)
) - set level (LS
) × M +
). The control configuration
can be selected as: 1) for normal
DCS mode or 2) for TON control mode.
This modification can be carried out
in the DCS with the help of an instrument
engineer. Apart from the selection
of DCS or TON, three fields exist
in DCS: target output, level set point
and factor M. Target output is the flow
control valve's average opening; the level
set point is the desired level to be maintained
(actual level indication value will
be taken from DCS); and M is a factor to
be set once as per operating practice and
flow variation with a level that is very
similar to controller gain-usually, it will
vary from 1-2.5.
Benefits. After implementation of TON
control in the above levels, the flow variation
was found to be significantly less
than the DCS. With this reduction in flow
variation, the performance of the stabilizer
was found to be stable, and the product
quality concerning LPG weathering was
steady. Due to a steady LPG flow after
the implementation of TON control, the
amine carryover problem with the LPG
was eliminated. Flow trend from DHDS,
DHDT and VGO wild and unstabilized
naphtha coming to the stabilizer after
TON control is shown in the lower half
of FIG. 1. The level and flow trend for the
CDU overhead coming to the re-contacting
column is shown in the lower half of
FIG. 2. The level, flow and control valve
opening trend for the stabilizer overhead
going to the amine extraction column is
shown in the bottom half of FIG. 3.
Additional level TON control was
implemented, such as a re-contacting column,
stabilizer bottom level and amine
KOD to further the improvement of the
saturated gas unit.
Takeaway. A CDU's stabilizer is a critical
section of any refinery. The steady
unit performance will reduce product
quality giveaway and increase profitability.
The steady LPG flow to the downsteam
amine section will eliminate amine
carryover along with LPG product. TON
control has been implemented in DHDS,
DHDT and the VGO MHC stripper and
stabilizer overhead section, the CDU
overhead, re-contacting column bottom,
stabilizer overhead and bottom level
control at the author's company.
LITERATURE CITED
1
2
3
Mandal, K. K., " New level control techniques, "
Hydrocarbon Processing, October 2004.
Mandal, K. K., et.al., " Improve desalter control, "
Hydrocarbon Processing, April 2005.
Mandal, K. K., " Search for advanced technique of
desalter control-TON control for interface level, "
Hydrocarbon Processing, January 2021.
4
Mandal, K. K., " Implementation of advanced
level control techniques in refinery operation, "
Hydrocarbon Processing, September 2021.
KISHORE KUMAR MANDAL is a
Technical Consultant for Nayara
Energy Ltd. in Vadinar, India. He
has worked on several different
refinery units, including atmospheric
vacuum distillations, FCCUs, DHDTs
and hydrocrackers. Mandal has
carried out assignments in commissioning, operations,
technical services and projects, and worked for Indian
Oil Corp. for 36 yr before retiring as the General
Manager. Mandal obtained his B.Tech degree in
chemical engineering from IIT, Kharagpur, India in 1982.
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Hydrocarbon Processing
36 NOVEMBER 2022 | HydrocarbonProcessing.com
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Hydrocarbon Processing - November 2022
Table of Contents for the Digital Edition of Hydrocarbon Processing - November 2022
Industry Perspectives
Editorial Comment
Construction
Innovations
Digital Technologies
Optimization of ethylene in the processing of hydrocarbons
Shift focus to more open control technology
Integrated remote operations drive collaboration and autonomy
Reliability analysis of analyzers bridges the gap between assessing and addressing risk
Implement advanced level control techniques to improve crude distillation unit stabilizer performance
Leading capital projects in a VUCA environment
Trip your turbine troubles: Optimize the reliability of steam-driven turbines
Development of novel epoxy closed-cell foam for personnel and corrosion protection—Part 2
Obsolescence management in a manufacturing unit
Decarbonizing your fired heaters with hydrogen fuel
Mechanical design challenges in high-temperature electric heaters
Why sulfur plants fail: An in-depth study of sulfur recovery unit failures—Part 2
Advertiser Index
Hydrocarbon Processing - November 2022 - 1
Hydrocarbon Processing - November 2022 - 2
Hydrocarbon Processing - November 2022 - 3
Hydrocarbon Processing - November 2022 - Industry Perspectives
Hydrocarbon Processing - November 2022 - 5
Hydrocarbon Processing - November 2022 - 6
Hydrocarbon Processing - November 2022 - Editorial Comment
Hydrocarbon Processing - November 2022 - 8
Hydrocarbon Processing - November 2022 - 9
Hydrocarbon Processing - November 2022 - Construction
Hydrocarbon Processing - November 2022 - 11
Hydrocarbon Processing - November 2022 - Innovations
Hydrocarbon Processing - November 2022 - 11B
Hydrocarbon Processing - November 2022 - 12
Hydrocarbon Processing - November 2022 - Digital Technologies
Hydrocarbon Processing - November 2022 - 14
Hydrocarbon Processing - November 2022 - 15
Hydrocarbon Processing - November 2022 - 16
Hydrocarbon Processing - November 2022 - Optimization of ethylene in the processing of hydrocarbons
Hydrocarbon Processing - November 2022 - 18
Hydrocarbon Processing - November 2022 - 19
Hydrocarbon Processing - November 2022 - 20
Hydrocarbon Processing - November 2022 - Shift focus to more open control technology
Hydrocarbon Processing - November 2022 - 22
Hydrocarbon Processing - November 2022 - 23
Hydrocarbon Processing - November 2022 - 24
Hydrocarbon Processing - November 2022 - Integrated remote operations drive collaboration and autonomy
Hydrocarbon Processing - November 2022 - 26
Hydrocarbon Processing - November 2022 - 27
Hydrocarbon Processing - November 2022 - 28
Hydrocarbon Processing - November 2022 - 29
Hydrocarbon Processing - November 2022 - 30
Hydrocarbon Processing - November 2022 - Reliability analysis of analyzers bridges the gap between assessing and addressing risk
Hydrocarbon Processing - November 2022 - 32
Hydrocarbon Processing - November 2022 - 33
Hydrocarbon Processing - November 2022 - Implement advanced level control techniques to improve crude distillation unit stabilizer performance
Hydrocarbon Processing - November 2022 - 35
Hydrocarbon Processing - November 2022 - 36
Hydrocarbon Processing - November 2022 - Leading capital projects in a VUCA environment
Hydrocarbon Processing - November 2022 - 38
Hydrocarbon Processing - November 2022 - Trip your turbine troubles: Optimize the reliability of steam-driven turbines
Hydrocarbon Processing - November 2022 - 40
Hydrocarbon Processing - November 2022 - 41
Hydrocarbon Processing - November 2022 - 42
Hydrocarbon Processing - November 2022 - 43
Hydrocarbon Processing - November 2022 - 44
Hydrocarbon Processing - November 2022 - 45
Hydrocarbon Processing - November 2022 - 46
Hydrocarbon Processing - November 2022 - Development of novel epoxy closed-cell foam for personnel and corrosion protection—Part 2
Hydrocarbon Processing - November 2022 - 48
Hydrocarbon Processing - November 2022 - 49
Hydrocarbon Processing - November 2022 - 50
Hydrocarbon Processing - November 2022 - Obsolescence management in a manufacturing unit
Hydrocarbon Processing - November 2022 - 50B
Hydrocarbon Processing - November 2022 - Decarbonizing your fired heaters with hydrogen fuel
Hydrocarbon Processing - November 2022 - 52
Hydrocarbon Processing - November 2022 - 53
Hydrocarbon Processing - November 2022 - 54
Hydrocarbon Processing - November 2022 - Mechanical design challenges in high-temperature electric heaters
Hydrocarbon Processing - November 2022 - 56
Hydrocarbon Processing - November 2022 - 57
Hydrocarbon Processing - November 2022 - 58
Hydrocarbon Processing - November 2022 - 59
Hydrocarbon Processing - November 2022 - 60
Hydrocarbon Processing - November 2022 - Why sulfur plants fail: An in-depth study of sulfur recovery unit failures—Part 2
Hydrocarbon Processing - November 2022 - 62
Hydrocarbon Processing - November 2022 - 63
Hydrocarbon Processing - November 2022 - 64
Hydrocarbon Processing - November 2022 - 65
Hydrocarbon Processing - November 2022 - Advertiser Index
Hydrocarbon Processing - November 2022 - 67
Hydrocarbon Processing - November 2022 - 68
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