Hydrocarbon Processing - December 2021 - GP-30
PLANT OPTIMIZATION
Optimize throughput of gas pipelines
and facilities with intelligent software
R. OTTO, Sensia Global, Calgary, Alberta, Canada
A drop of liquid. An ice formation. So
small and yet so potentially costly and
damaging to the operations of gas facilities
and pipelines. Unwanted hydrates or
liquids can clog pipes, reduce the process
flow and damage equipment.
Gas processing technologies depend
on understanding the phase envelope of
the process fluid to operate efficiently
and safely. Process engineers implement
their designs to manage the worst anticipated
phase envelope, normally resulting
in less-than-optimal throughput and unnecessary
energy use for typical or normal
operating conditions.
To deal with these challenges, intricate
calculations are needed and control
actions must happen in real time.
Most operators
adjust
controls
to
operate the plant or the pipeline a safe
distance from the formation of hydrates
or well into the phase the process needs
to operate on. This is accomplished by
injecting chemicals, increasing the temperature
of the gas with heaters, reducing
temperatures far below what is needed,
or operating well below the design capacity.
The first three methods increase the
operational cost and indirectly reduce
throughput. The last one directly reduces
throughput. Consequently, opportunities
to improve yield and efficiency dissipate.
All this in an industry era marked by
falling budgets for capital and operational
expenditures (CAPEX and OPEX).
While this is true at many gas facilities
and pipelines operating today, it no longer
has to be that way.
Increasing throughput and reliability.
Until recently, no solution existed for the
control system to adapt operations based
on real-time conditions and compositions.
Historically, process engineers calculated
processing fluid simulations using
spreadsheets on a desktop computer and
shared them with the control engineers
to implement. Those calculations helped
ensure the plant operated in safe operating
conditions, based on the expected
range of the compositions of the process
fluid. However, these calculations are
based on safeguarding against worst-case
scenarios, such as extreme temperatures
or the poor quality of a raw material, and
most of the time these facilities operate
under much better circumstances.
Using intelligent throughput optimization
software, that simulation capability
can become a real-time control system
activity to help prevent reliability issues
and increase throughput. With insights
provided by the software as the compoFIG.
1. The phase envelope and hydrate curves for a refrigeration process. Both graphs show the same facility.
30 NOVEMBER/DECEMBER 2021 | GasProcessingNews.com
http://www.GasProcessingNews.com
Hydrocarbon Processing - December 2021
Table of Contents for the Digital Edition of Hydrocarbon Processing - December 2021
Contents
Hydrocarbon Processing - December 2021 - Cover1
Hydrocarbon Processing - December 2021 - Cover2
Hydrocarbon Processing - December 2021 - Contents
Hydrocarbon Processing - December 2021 - 4
Hydrocarbon Processing - December 2021 - 5
Hydrocarbon Processing - December 2021 - 6
Hydrocarbon Processing - December 2021 - 7
Hydrocarbon Processing - December 2021 - 8
Hydrocarbon Processing - December 2021 - 9
Hydrocarbon Processing - December 2021 - 10
Hydrocarbon Processing - December 2021 - 11
Hydrocarbon Processing - December 2021 - 12
Hydrocarbon Processing - December 2021 - 13
Hydrocarbon Processing - December 2021 - 14
Hydrocarbon Processing - December 2021 - 15
Hydrocarbon Processing - December 2021 - 16
Hydrocarbon Processing - December 2021 - 17
Hydrocarbon Processing - December 2021 - 18
Hydrocarbon Processing - December 2021 - 19
Hydrocarbon Processing - December 2021 - 20
Hydrocarbon Processing - December 2021 - 21
Hydrocarbon Processing - December 2021 - 22
Hydrocarbon Processing - December 2021 - 23
Hydrocarbon Processing - December 2021 - 24
Hydrocarbon Processing - December 2021 - 25
Hydrocarbon Processing - December 2021 - 26
Hydrocarbon Processing - December 2021 - 27
Hydrocarbon Processing - December 2021 - 28
Hydrocarbon Processing - December 2021 - 29
Hydrocarbon Processing - December 2021 - 30
Hydrocarbon Processing - December 2021 - 31
Hydrocarbon Processing - December 2021 - 32
Hydrocarbon Processing - December 2021 - 33
Hydrocarbon Processing - December 2021 - 34
Hydrocarbon Processing - December 2021 - 35
Hydrocarbon Processing - December 2021 - 36
Hydrocarbon Processing - December 2021 - 37
Hydrocarbon Processing - December 2021 - 38
Hydrocarbon Processing - December 2021 - 39
Hydrocarbon Processing - December 2021 - 40
Hydrocarbon Processing - December 2021 - 41
Hydrocarbon Processing - December 2021 - 42
Hydrocarbon Processing - December 2021 - 43
Hydrocarbon Processing - December 2021 - 44
Hydrocarbon Processing - December 2021 - 45
Hydrocarbon Processing - December 2021 - 46
Hydrocarbon Processing - December 2021 - 47
Hydrocarbon Processing - December 2021 - 48
Hydrocarbon Processing - December 2021 - 49
Hydrocarbon Processing - December 2021 - 50
Hydrocarbon Processing - December 2021 - 51
Hydrocarbon Processing - December 2021 - 52
Hydrocarbon Processing - December 2021 - 53
Hydrocarbon Processing - December 2021 - 54
Hydrocarbon Processing - December 2021 - 55
Hydrocarbon Processing - December 2021 - 56
Hydrocarbon Processing - December 2021 - 57
Hydrocarbon Processing - December 2021 - 58
Hydrocarbon Processing - December 2021 - 59
Hydrocarbon Processing - December 2021 - 60
Hydrocarbon Processing - December 2021 - 61
Hydrocarbon Processing - December 2021 - 62
Hydrocarbon Processing - December 2021 - 63
Hydrocarbon Processing - December 2021 - 64
Hydrocarbon Processing - December 2021 - 65
Hydrocarbon Processing - December 2021 - 66
Hydrocarbon Processing - December 2021 - 67
Hydrocarbon Processing - December 2021 - 68
Hydrocarbon Processing - December 2021 - 69
Hydrocarbon Processing - December 2021 - 70
Hydrocarbon Processing - December 2021 - 71
Hydrocarbon Processing - December 2021 - 72
Hydrocarbon Processing - December 2021 - 73
Hydrocarbon Processing - December 2021 - 74
Hydrocarbon Processing - December 2021 - 75
Hydrocarbon Processing - December 2021 - 76
Hydrocarbon Processing - December 2021 - 77
Hydrocarbon Processing - December 2021 - 78
Hydrocarbon Processing - December 2021 - 79
Hydrocarbon Processing - December 2021 - 80
Hydrocarbon Processing - December 2021 - 81
Hydrocarbon Processing - December 2021 - 82
Hydrocarbon Processing - December 2021 - Cover3
Hydrocarbon Processing - December 2021 - Cover4
Hydrocarbon Processing - December 2021 - GP-1
Hydrocarbon Processing - December 2021 - GP-2
Hydrocarbon Processing - December 2021 - GP-3
Hydrocarbon Processing - December 2021 - GP-4
Hydrocarbon Processing - December 2021 - GP-5
Hydrocarbon Processing - December 2021 - GP-6
Hydrocarbon Processing - December 2021 - GP-7
Hydrocarbon Processing - December 2021 - GP-8
Hydrocarbon Processing - December 2021 - GP-9
Hydrocarbon Processing - December 2021 - GP-10
Hydrocarbon Processing - December 2021 - GP-11
Hydrocarbon Processing - December 2021 - GP-12
Hydrocarbon Processing - December 2021 - GP-13
Hydrocarbon Processing - December 2021 - GP-14
Hydrocarbon Processing - December 2021 - GP-15
Hydrocarbon Processing - December 2021 - GP-16
Hydrocarbon Processing - December 2021 - GP-17
Hydrocarbon Processing - December 2021 - GP-18
Hydrocarbon Processing - December 2021 - GP-19
Hydrocarbon Processing - December 2021 - GP-20
Hydrocarbon Processing - December 2021 - GP-21
Hydrocarbon Processing - December 2021 - GP-22
Hydrocarbon Processing - December 2021 - GP-23
Hydrocarbon Processing - December 2021 - GP-24
Hydrocarbon Processing - December 2021 - GP-25
Hydrocarbon Processing - December 2021 - GP-26
Hydrocarbon Processing - December 2021 - GP-27
Hydrocarbon Processing - December 2021 - GP-28
Hydrocarbon Processing - December 2021 - GP-29
Hydrocarbon Processing - December 2021 - GP-30
Hydrocarbon Processing - December 2021 - GP-31
Hydrocarbon Processing - December 2021 - GP-32
Hydrocarbon Processing - December 2021 - GP-33
Hydrocarbon Processing - December 2021 - GP-34
Hydrocarbon Processing - December 2021 - GP-35
Hydrocarbon Processing - December 2021 - GP-36
Hydrocarbon Processing - December 2021 - GP-37
Hydrocarbon Processing - December 2021 - GP-38
Hydrocarbon Processing - December 2021 - GP-39
Hydrocarbon Processing - December 2021 - GP-40
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hpi-market-data-2024-v2
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hpi-market-data-2024
https://www.nxtbook.com/gulfenergyinfo/gulfpub/gas-processes-handbook-2022_v2
https://www.nxtbook.com/gulfenergyinfo/gulfpub/gas-processes-handbook-2022
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hp_202212
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hpi-market-data-2023-v2
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hpi-market-data-2023
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hp_202211
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202210
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202209
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202208
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202207_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202207
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202206_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202206
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202205_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202205
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202204_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202204
https://www.nxtbook.com/nxtbooks/gulfpub/hp_032022
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202203
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202202
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202201
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202112
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202111
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202110
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2022_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2022
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202109
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202108
https://www.nxtbook.com/nxtbooks/gulfpub/petrochemical_processes_handbook_2021_v2
https://www.nxtbook.com/nxtbooks/gulfpub/petrochemical_processes_handbook_2021
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202107
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202106
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202105
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202104
https://www.nxtbook.com/nxtbooks/gulfpub/hp_ebooks
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202103
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202102
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202101
https://www.nxtbook.com/nxtbooks/gulfpub/catalyst_handbook_2020_v2
https://www.nxtbook.com/nxtbooks/gulfpub/catalyst_handbook_2020
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202012
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202011
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202010
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2021
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202009
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202008
https://www.nxtbook.com/nxtbooks/gulfpub/refining_processes_handbook_2020
https://www.nxtbook.com/nxtbooks/gulfpub/refining_processes_handbook_2020_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202007
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202006
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202005
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202004
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202003
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202002
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202001
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201912
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201911
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2020_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2020
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201910
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201909
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201908
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201907
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201906
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201905
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201904
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201903
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201902
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201901
https://www.nxtbook.com/nxtbooks/gulfpub/petrochemical_2018_v2
https://www.nxtbook.com/nxtbooks/gulfpub/petrochemical_2018
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201812
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2019_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2019
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201811
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201810
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201809
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201808
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201807
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201806
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201805
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201804
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201803
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201802
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201801
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201712
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201711
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201710
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201709
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201708
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201707
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201706
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201705
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201704
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201703
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201702
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201701
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2017mediaplanner
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201612
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201611
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201610
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201609
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201608
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201607
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201606
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201605
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201604
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201603
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201602
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201601
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201512
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201511
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201510
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2016mediaplanner
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201509
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201508
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201507
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2015tmsd
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201506
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201505
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201504
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201503
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201502
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201501
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201412
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201411
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2015mediaplanner
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201410
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201409
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201408
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201407
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2014petrochemicalprocesses_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2014petrochemicalprocesses
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201406
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201405
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201404
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201403
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2014calendar
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201402
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201401
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201312
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2014mediaplanner
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201311
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201310
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201309
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201308
https://www.nxtbook.com/nxtbooks/gulfpub/hp_srsguide2013
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201307
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201306
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201305
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201304
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201303
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201302
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201301
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201212
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201211
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201210
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201209
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201208
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201207
https://www.nxtbook.com/nxtbooks/gulfpub/hp_srsguide2012
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201206
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201205
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201204
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201203
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201202
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201201
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201112
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201111
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201110
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201109
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201108
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201107_srsguide
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201107
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201106
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201105
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201104
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201103
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201102
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201101
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201012
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201011
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201010
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201009
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201008
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201007
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201006
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201005
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201004
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201003
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201002
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201001
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200912
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200911
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200910
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200909
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200908
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200907
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200906
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200905
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200904
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200903
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200902
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200901
https://www.nxtbookmedia.com