Hydrocarbon Processing - December 2021 - GP-35
PLANT OPTIMIZATION
LPG or high recoveries of C2
C3+ components are required
and
* The major benefit of the
turboexpander scheme is
the utilization of expansion
energy for the recompression
of gas; therefore, the energy
requirement for the external
sales gas compressor is reduced
* The existence of complex
rotating equipment
(expander and compressor)
demands maintenance and
operation expertise, which
impacts the availability and
reliability of the plant
* Being complex and high in capital
cost, turboexpander technology
is used for high and constant
feed flowrates, and it is difficult
to control and turndown
* When used for cryogenic
process, almost fully dehydrated
gas is required by turboexpander
technology to prevent hydrate
formation, as LTS temperature
will drop in cryogenic range;
therefore, a solid-bed system or
a silica gel-based dehydration
unit is required instead of a glycol
dehydration unit to dehydrate the
gas completely before processing
it through a turboexpander
* With the use of this technology,
very low hydrocarbon
dewpoint can be achieved.
JT valve technology. In principle,
JT valve technology utilizes the JouleThomson
effect to achieve the required
cooling for separation of heavier hydrocarbons,
thereby attaining dewpoint reduction
in gas at the outlet of the unit.
Gaseous hydrocarbons are cooled by
throttling its flow through the JT valve,
initiating rapid expansion. This phenomenon
is known as the Joules Thomson
effect. The quantity of NGLs recovered
is a function of the gas composition,
pressure, temperature and pressure drop
across the JT valve.
Gas from upstream of the processing
unit is routed to a gas/gas heat exchanger,
which provides a means of heat exchange
between the raw gas and LTS gas; therefore,
precooling of the raw gas is achieved
in the heat exchanger. As the temperature
drops, some condensation occurs downstream
of the gas/ gas exchanger.
FIG. 3. Process scheme for turboexpander technology.
Outlet gas from the cold separator is
then adiabatically expanded through a
pressure control valve (JT valve).
The decrease in temperature due to
expansion promotes further condensation.
The combined stream (gas, condensed
hydrocarbon and the EG/methanol
solution) is then introduced in the
LTS to segregate gas, liquid hydrocarbons
and the ethylene glycol solution.
After the separation of NGL, gas
from the LTS will have dewpoint as per
pipeline specifications; however, it still
requires compression. This dewpointspecified
gas is then routed through the
gas/gas heat exchanger to exchange heat
with raw gas, followed by compression
through the sales gas compressor up to
the required sales gas pressure.
EG or methanol is injected in raw gas
at the inlet of the gas/gas exchanger to
avoid possible hydrate formation at low
operating temperature. Rich EG/methanol
solution collected from the LTS is
routed to the glycol/methanol regeneration
system, which, after processing, recycles
back lean ethylene glycol solution
to the dewpoint reduction unit.
Condensate (NGL) from the LTS
is first passed through the multipass exchanger
to raise its temperature above the
hydrate formation temperature before
being routed to NGL storage (FIG. 5).
Phase envelope. Proprietary simulation
steady-state softwarea
is utilized to
simulate the hydrocarbon dewpoint control
unit. FIG. 6 reveals the phase envelope
for lean sales gas after processing through
a JT valve-based hydrocarbon dewpoint
control unit.
FIG. 4. Phase envelope for lean sales gas after processing through the turboexpander-based
hydrocarbon dewpoint control unit.
Gas Processing & LNG | NOVEMBER/DECEMBER 2021 35
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-2023-v3
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