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Commissioning of first world scale KBR PurifierTM ammonia plant
in
North America
The Dyno Nobel Louisiana Ammonia (DNLA) project is one of the
biggest expansion activities ever undertaken by its Australian
based parent company, Incitec Pivot Ltd (IPL), increasing the
annual ammonia production by about 800,000 tonnes per year. The
Engineering, Procurement, and Con-struction (EPC) for this project
was carried out by the Houston, TX based Kellogg Brown &
Root
(KBR) using their PurifierTM ammonia technology and project
ground breaking was commenced in August 2013.
In mid-2015, KBR completed the construction of Dyno Nobel's
Waggaman ammonia plant in Louisi-ana and commenced start-up
activities of its 2300 MTPD Ammonia Plant – the first world scale
KBR
PurifierTM technology based ammonia plant in North America.
Commissioning was successfully completed in October 2016 with
one of the lowest energy consump-tion figures per tonne of ammonia.
This paper presents an overview of the project and its journey
through the various stages of project development, design,
engineering, and construction as well as challenges experienced in
whole project process. It also describes both KBR and Dyno Nobel
experi-ence in the commissioning and start-up of the process
facilities, the problems encountered and key
lessons learned during the commissioning.
Venkat Pattabathula, Chris Morgan and Morris Hofman
Dyno Nobel Inc.
George Colman and Avinash Malhotra Kellogg Brown & Root
(KBR)
Introduction he growth of ammonia industry has been languishing
in the USA for about 30 years. However a step change has oc-curred
since the shale gas industry was
developed and the gas prices became affordable and therefore
attractive to the ammonia produc-ers. Hence, more ammonia capacity
is being
added to supplement existing operating capaci-ties to meet the
USA’s ammonia demand. Australia’s, Incitec Pivot, the parent
company of Dyno Nobel Louisiana Ammonia (DNLA), in-stalled the
plant with an annual ammonia capac-ity of 800,000 metric tons at
Cornerstone Chem-ical’s 800-acre Fortier Manufacturing Complex at
Waggaman in Louisiana (WALA).
T
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Dyno Nobel operates ammonium nitrate facili-ties in some of the
states in the US. Incitec Pivot Limited developed the Dyno Nobel
ammonia plant to support its U.S. industrial explosives business
and external customers including Cor-nerstone which produces
acrylonitrile, mela-mine and sulfuric acid at the Fortier complex.
Dyno Nobel’s ammonia plant is integrated with Cornerstone’s
existing plant infrastructure and share utilities and facilities
such as the river ex-port dock, the rail facilities and the ability
to in-ject ammonia in to the 2000 mile Nustar ammo-nia distribution
pipeline It is the first ammonia plant to have been built in the
state of Louisiana in over 25 years. The Dyno Nobel new ammonia
plant utilizes the KBR PurifierTM ammonia technology. The plant is
a world scale KBR PurifierTM plant having a design capacity of 2300
MTPD (2536 STPD). Ammonia Process Design Features The Ammonia Plant
is based on the KBR Puri-fierTM flowsheet as shown in Figure-A1 and
another image of nightline view of the plant is shown in Figure
A-2. The plant design is based upon the natural gas composition
listed in Table-1 below.
Components Mole Fraction,% CH4 97.98 C2H6 0.78 C3H8 0.11 C4H10
0.04 C5H12 0.02 C6H14 0.01 N2 0.31 CO2 0.75
Table 1. Natural Gas Feed Composition The salient design
features of the Dyno Nobel Waggaman, Louisiana (WALA) plant
are:
Mild conditions for primary reforming
via excess air to the secondary reformer Primary reformer having
only steam tur-
bine driven forced and induced draft fans
KBR’s natural circulation, removable tube bundle water tube
Waste Boiler De-sign, downstream of secondary reformer.
KBR’s nonmetallic Mixing Chamber (no metallic mixer or burner)
in the Second-ary Reformer.
BASF’s two stage CO2 removal system using the OASE White
(activated MDEA) solvent.
KBR PurifierTM for providing a clean, dry makeup of synthesis
gas to Synthesis Loop. PurifierTM precisely controls H2: N2 ratio
and removes all methane and the majority of the argon present.
KBR’s cold wall single Horizontal Am-monia Synthesis Converter
with 3 cata-lyst beds and 2 interchangers
KBR’s four stage Unitized Chiller in synthesis loop.
No separate purge gas - Hydrogen Re-covery System is
required.
Two flares one for front and other one for back-end vent
headers.
Selective catalytic reduction (SCR) unit in reformer convection
section to reduce NOx levels in flue gas
Use of KBR’s operator training simula-tor
Plant uses catalysts supplied by KBR/Clariant that includes
non-hexavalent chrome HTS catalyst and Wustite based AmoMax
Synthesis cata-lyst.
For plant start-up, the feed gas compressor is utilized for
front end nitrogen recirculation.
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Plant Performance The plant performance guarantee test was
conducted over a 72-hour period in October 2016 with all guarantees
successfully met: Guarantee item Guarantee
value Measured Value
Ammonia production, st/d
2536 2576
Ammonia product quality: NH3,% H2O,%
99.8 min. 0.2 max.
99.99 0.01
Net energy consumption, MMBtu/ton, LHV
25.09 24.84
Inerts in CO2, % 2 max. 0.17 Carbon dioxide purity CO2,%
98.0 min.
99.83
Table 2. Guarantee & Measured Numbers In addition to the
above, environmental re-quirements were also met as part of
perfor-mance guarantees and those were listed in Table 3. Guarantee
Item Guarantee Value NOX 10 ppmv dry basis Carbon Monoxide 50 ppmv
dry basis Ammonia 10 ppmv dry basis Particulate Matter PM10
7.1 lbs/hr
Table 3 – Environmental Performance Project Execution The
project kick-off was in September 2012 with an Engineering,
Procurement and Construction scheme (EPC Contract) as a lump sum
turnkey project. The EPC contract was awarded to Kellogg Brown
& Root (KBR). Beside the ammonia plant, the project also
con-sisted of a 35,000 MT ammonia storage tank, barge and road
tanker loading system and utility plants that included water
clarifier (Coag unit),
cooling water system, Ultra Filtration (UF), re-verse osmosis
(RO) unit and Ion Exchange (mixed beds) units. Ground breaking
occurred in August 2013 with the plant mechanical acceptance having
achieved in March 2016, and commercial operation declared in
September 2016. The main project milestones are listed in Table-4.
Major Events Date Effective date of contract 13 April 2013 Basic
engineering completion 15 June 2013 Detail engineering
completion
End 2014
Ground breaking 5 Aug 2013 Precommissioning phase July 2015
-
March 2016 Natural gas receiving Oct 2015 Commissioning start
(Reformer 1st firing)
25April 2016
Feed-in to primary reformer 9 May 2016 Syngas compressor start
26 June 2016 Catalyst reduction of ammo-nia synthesis converter
start
24 July 2016
First ammonia produced 27 July 2016 Performance test completed
13 Oct 2016 Plant acceptance 19 Oct 2016 Table 4. Key Milestones of
DNLA Project First ammonia production was successfully
ac-complished 78 days after the initial introduction of natural gas
feed. However, during plant ini-tial operation, numerous issues
were encoun-tered which required an additional 3 months be-fore the
plant performance tests were successfully completed. The project
used a local construction workforce of around 1200 at peak
construction activity. Safety Performance The project achieved
outstanding Zero Harm performance with 5 million work hours without
a single lost time injury (LTI). This is a merito-rious achievement
on a project of this size.
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Commissioning and Start-Up As part of EPC contract, KBR has
provided a complete team for start-up, supported by Dyno Nobel’s
project team and Cornerstone’s opera-tions team. KBR also trained
Dyno operations team using a dynamic process simulator in addi-tion
to class room training. Problems that arose during plant
commissioning were jointly resolved by the KBR EPC, Technology and
owner’s process, electrical, instrument, and mechanical teams. Use
of Temporary Boilers Due to project contractual and schedule
con-straints, very early in the project KBR was to supply the MP
steam requirement for plant pre-commissioning, commissioning, and
initial startup/operation from portable boilers. To meet the
plant’s peak MP steam demand of about 300,000 lbs/hr (136,000
kgs/hr) four port-able boilers were installed. Additionally, an air
emissions permit was ob-tained from the state of Louisiana to
operate the boilers. Each boiler was capable of producing 75,000
lbs/ hr (34,000 kgs/hr) of steam at a pressure of 750psig (5171
kPag) and a temperature of 750F (400C). The use of the portable
boilers required the in-stallation of additional systems for:
a) Supply of boiler feed water, natural gas for fuel, instrument
air, steam drum treatment chemicals
b) Collection and cooling of boiler steam drum blowdown
water
c) Instrumentation and controls
Figure 1. Temporary Boilers
Figure 1a. Temporary Boilers
Challenges Experienced During Commissioning Below is a summary
of some of the main issues encountered during the plant initial
start-up and operation. Successful commissioning of an ammonia
plant requires careful planning and utilization of les-sons learned
from other successful startups. Equipment Preservation Equipment
preservation is an essential compo-nent of any project
implementation plan. The purpose of an equipment preservation
program is to ensure that all new equipment remains in
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the same condition as it left the factory until it is placed in
service during the initial plant start-up. Typically equipment
preservation programs comprise of the following key elements:
a) Initial preservation – application of pre-servatives and the
fitting of specific pro-tection to equipment by suppliers prior to
equipment shipment
b) Maintenance preservation – periodic ac-tivities to confirm
the initial preservation is intact and functioning. This also
in-cludes the repair of deteriorated initial preservation and also
performing any additional supplier recommended field preservation
activities
c) The regular rotating of pumps and com-pressors is essential
to ensure that bear-ings and shafts are not damaged.
d) Preservation renewal – if the time be-tween the initial
preservation and plac-ing of the equipment into service ex-ceeds
that stated in the equipment supplier preservation guidelines, then
it will be necessary to seek the equipment supplier’s advice as to
the requirement to renew the initial preservations
During plant construction and commissioning, especially after
the start of the hydro test pro-gram additional attention is
required to ensuring that equipment preservation requirements are
maintained. The following photographs show some exam-ples from the
Dyno Nobel ammonia plant pro-ject of equipment damage resulting
from com-promised equipment preservation. The WALA project
experience highlights the importance of a robust equipment
preservation program, thorough plant pre-start-up checkout, and
effective pre-commissioning practices.
Figure 2. Steam turbine 108JT Rotor
Figure 2a. Damaged TTV
Damage caused by compromised equipment preservation resulted in
additional project costs and numerous delays to the plant
pre-commissioning, commissioning, and initial start-up schedules.
Process Air Machine Damage Air for the process is supplied by a six
stage in-tegrally geared compressor supplied by Sie-mens. The air
compressor is fitted with shell and tube inter stage coolers.
During machine surge mapping, the process air machine tripped on
high 5th stage vibrations. In the ensuing trip an oil leak from the
bull gear
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assembly ignited causing a small flash fire which was rapidly
extinguished. Also during the machine trip, the 6th stage process
air discharge pipe work was dislodged from its supports. Opening of
the machine revealed the damage shown in the following
photographs.
Figure 3. Parts of hessian sack found in com-
pressor
Figure 4. Impeller damage
Figure 5. Stage 5 Impeller
Figure 6. Stage 6 Impeller
Figure 7. Dislocated piping support
Figure 8. Stage 5 tie bolt
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An incident investigation pinpointed the root cause of the
compressor trip and damage to be a hessian (burlap) sack containing
bead blast ma-terial which became dis-lodged from the shell side of
the intercooler located between the 4th and 5th stages and entered
the 5th stage of the machine. Repair work necessitated the complete
disman-tling of the compressor/bull gear end of the ma-chine which
was then returned to a Siemens workshop in Houston for repair and
reassembly. Machine repairs and reassembly took a total of 9 weeks.
OASE White Solution System Foaming of the recirculating OASE White
solu-tion may cause a major process upset resulting in an
interruption to ammonia production or worst case scenario of a loss
of containment of the OASE White solution through the carbon
dioxide atmospheric vent into the surrounding plant environment.
The keys to preventing foaming of the OASE White solution are:
a) System cleaning during plant pre-commissioning to ensure
effective re-moval of foam causing agents such as oils, greases,
and fine particle/dusts
b) Low temperature shift catalyst de-dusting following catalyst
reduction
c) Continuous filtration of the recirculating OASE White
solution during plant initial start-up/operation
d) Close management of the anti-foam ad-dition program in the
plant initial start-up/operation.
During the Dyno Nobel project due to a multi-tude of reasons the
cleaning of the OASE White system was not completely effective. To
miti-gate the effect of a less than effective system cleaning upon
initial plant operation, a tempo-rary side stream carbon bed
filtration unit was installed. The temporary filtration unit has
helped to bring the color of the recirculating
OASE solution to normal and side stream filters remained in
service for 3 months until the 5 mi-cron filter socks would operate
for five continu-ous days without increasing pressure drop.
Additionally, to preempt the occurrence of foaming, foaming tests
were carried out twice a shift of the recirculating OASE White
solution and adjustments were made to the anti-foam in-jection
program which comprised of continuous injection using the installed
anti-foam injection pump skid and also each shift “shot” dosing
us-ing the installed “shot pots”. The aforemen-tioned measures
resulted in zero OASE White solution foaming events during the
plant initial start-up/operation period. High Pressure Leak
Checking The synthesis section of modern day ammonia plants operate
at pressures up to 165kg/cm2(g) (2347 psig) temperatures up to
530oC (986F) and contains process gas with hydrogen concen-trations
of up to 75 mole%. In the event of a process gas leak from this
section of the plant there is a high degree of probability that a
hy-drogen jet fire could potentially occur causing severe damage to
surrounding plant and equip-ment. To mitigate such an event KBR
took the deci-sion to perform a rigorous high pressure leak check
before initial plant start-up at a pressure 90% of the lowest set
pressure relief device of the ammonia synthesis loop. The leak
check was performed after completion of both ammonia synthesis
catalyst loading and ammonia synthe-sis converter box-up and
included all associated instrumentation. To prevent an uncontrolled
oxidation of pre-reduced ammonia synthesis catalyst contained in
the 1st bed of the ammonia synthesis convert-er it was necessary to
perform the leak check with high pressure gaseous nitrogen supplied
at ambient temperature from a liquid nitrogen pumper truck. The
leak check was performed in
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pressure increments of 20kg/cm2 (300 psig). While holding at
each pressure increment all po-tential leakage points were checked
for signs of leakage using a leak detection fluid.
Figure 9. Liquid Nitrogen Pumper Truck
The aforementioned leak checking revealed numerous leaks which
were fully remediated prior to the introduction of process gas to
the ammonia synthesis loop both eliminating a po-tential serious
safety hazard and also shortening the critical path to the
production of the 1st drops of ammonia. Tuning Of Synthesis Gas
Compressor Perfor-mance Control A key element to the successful
operation of the PurifierTM package unit in the Dyno Nobel am-monia
plant project is the tuning of the synthesis gas compressor
performance controller. The pressure of the process gas at the
suction of the synthesis gas compressor is controlled by the
synthesis gas compressor performance con-troller which modulate the
synthesis gas com-pressor speed to maintain this pressure steady.
In the case of the Dyno Nobel plant the synthe-sis gas compressor
performance controller was tuned such that the variations in
suction pressure are less than +/- 0.25psi.
Figure 10. Syngas compressor suction pressure trend chart
Summary Despite the problems faced, the Dyno Nobel, WALA plant
successfully met all its energy consumption, production, and
product quality guarantees. The project was a great success with
more than 5 million work hours LTI free and the project came online
ahead of other similar scale major ammonia projects in the
continent. Acknowledgement We would like to acknowledge the
untiring ef-forts put in by KBR and WALA teams in the successful
commissioning of the first world scale KBR PurifierTM plant in
North America.
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Figu
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Pro
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Flo
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Fi
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. Nig
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of D
yno
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