Challenges in the Integration of the QAFCO 5 & 6 Mega Fertilizer

Complex The new QAFCO 5 and 6 complex is located about 3 kilometers west o/the QAFCO fertilizer industrial area. Tile new complex is generally independent o/the previous facilities, but il is

interconnected 10 the QAFCO site/or sea water cooling system, C02 supply, product export etc. In addition, the steam, electric power and cooling water systems as well as the primary process units oj

the complex are internally integrated. This paper describes the challenges faced in the design, construction, commissioning, initial operation and the effective management o/the different

schedules o/implementation in a rohust and safe integrated scheme.

Andrea Zarnbianco Saipem S.p.A.

Mohamed Noueiri QAFCO

Introduction

S aipem is a large, international and one of the best balanced turnkey contractors in the oil & gas industry. Saipem has a strong bias towards oil and gas related ac­

tivities in remote areas and deep water and is a leader in the provision of engineering, procure­ment, project management and construction ser­vices. Saipem has distinctive capabilities in the design and the execution of large-scale offshore and onshore projects, and technological compe­tencies such as gas monetization and heavy oil exploitation. Saipem is a global contractor, with strong local presence in strategic and emerging areas such as West Africa, North Africa, FSU, Central Asia, Middle East, and South East Asia. Saipem employs over 48,000 people comprising more than 127 nationalities. Its clients and peo-

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pie - in particular their health and safety - are the primary focus of all Saipem activity. Saipem has a distinctive Health & Safety Environment Management System and its Quality Manage­ment System has been gronted ISO 9001:2000 certification by Lloyd's Register Certification.

Qatar Ferti lizer Company (QAFCO) was found­ed in 1969 as a joint venture between the Gov­ernment of Qatar and a number of foreign shareholders. It is now 75% owned by Industries Qatar (IQ) and 25% by Yara Netherland. With a sizable annual capacity of 3.8 million MT of ammonia and 5.6 million MT of urea QAFCO is now the world' s largest single-site producer of ammonia and urea. This enables Qatar to be a key player in the global ferti lizer market and the largest exporter of urea in the world (15% share of the world urea supply).

AMMONIA TECHNICAL MANUAL

QAFCO started production in 1973 with a sin­gle ammonia/urea train with a nominal capacity of 900 MT ammonia and 1,000 MT of Urea dai­ly. Since then due to the continuous develop­ments and the very high level of operation effi­ciency the total production capacity of the company has been enormously expanded. Pres­ently the QAFCO complex comprises six fu lly integrated ammonia/urea trains. The last two trains, QAFC05/QAFC06 (Q5 /Q6), are the ones being discussed in this paper.

Project Description

Q5 and Q6 Projects represent one of the largest and most challenging execution in the ferti lizer field worldwide. Q5 Project was started in De­cember 2007 and was handed over to QAFCO during August 2012. The Q6 Project was started in October 2009 and was handed over to QAFCO during September 2012.

The two projects were executed in the following three main locations: (I) the new Q5 and Q6 site, (2) the existing QAFCO 1-4 (Q 1-4) site and (3) a 3 km long IntercOlUlcction Piperack (ICPR).

The new Q5 and Q6 sites mainly consist of two ammonia plants each at 2,300 MTPD, two Urea granulation plants each at 3,850 MTPD and one 85% Urea Formaldehyde Concentrate (UFC-85) 85 MTP plant. Other features include:

Description Key featu res I (des il(n values)

Sea Water multi-cell s cooling 34 cells unit Close Cooling Water system 64000 m3/h

Electro-chlorination system 2 x 50%; 10 kg/h of active chlorine each

Desalination plant 225 m3/h

two Urea Bulk Halls of 100,000 MT and 175,000 MT

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Urea Export system (Pipe 1,000 MT/h Conveyors) 5 Cogeneration units eacb train

42.1 MW ( ISO rated) + 150TIh of steam

two auxiliary boi lers 120 Tih (each) one Steam Turbine generator 62.5 MW 132 K V electrical substation Connected to

national grid thennal concentrator 12 m31h rated evaporation pond 16,000 m2

The ICPR carries the Sea Water make up and blow down, two ammonia export li nes, two urea export pipe conveyors, C02 transfer line, the de­salinated water interconnection with Q 1-4 and the nitrogen supply line. ICPR area is inter­spersed by several existing infrastructures, un­derground pipelines and cables and industrial roads.

New faci lities in Q 1-4 site consist mainly of a new electrical substation to distribute power in the Q 1-4 site, two Cogeneration units with steam production integrated with the existing steam system in QI-4 site, Sea Water make up pumping facilities with its own filtration system, two ammonia tanks of 50,000 MT capacity each with an outer concrete protection wall, ammonia export system 1,000 MTIh, C02 booster com­pressor to transfer excess C02 from the Ql-4 site to the urea plants in Q516 site, handling system interconnection with ex isting bulk hall and bagging system, ex isting Jetty extension for large vessels.

Background

In June 2005 QAFCO nominated a team to de­velop the concept for the Q5 project. The man­date was to increase QAFCO's ammonia and urea production capacity and to integrate it with the a lready existing faci lities. Due to space limi­tations in the existing site a new location was eannarked for the new development within the Mesaieed Industrial City fence (MlC). The new

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site is around 3km north east of the existing site and is separated from it by roads , pipelines and electrical cables posing a real obstacle to any connections that may be necessary between the two sites. The intention for the Q5 project was to have two ammonia plants and a single urea plant with all the necessary utilities and export systems designed to accommodate the second urea plant at some point in the future. The pro­ject team had to provide a solution that would overcome the following constraints: • Geographical constraints: The new site is in­

land with no access to sea water and jetties for export.

• Logistical constraints: A principal decision was made that this project should include the revamping of the whole electrical net­work in QAFCO. This included the decom­missioning of the old high emission power plant and some high emission auxiliary boil­ers and the installation of sufficient power generation capacity to allow all the facilities in QAFCO to run on island mode. The re­quirements included that the trip of any gen­erator should not result in any production loss.

• Local regulatory constraints: This included all environmental and local authority limita­tions. Environmental impact minimization and access to sea water cooling and dis­charges for the new plants are all limited by new requirements.

• Constraints from existing facilities: This in­cludes the fact that many of the existing fa­cilities and utilities have their own limita­tions. Instrument air, nitrogen, cooling water, fire water etc... all are highly stretched. Any tie-in to existing facilities will have to take into account that these are limited and may be needed for another pro­ject that may come before the implementa­tion ofQ5/6.

The Q6 Project came as an addendum to the Q5 Project. It included and additional urea plant and all its associated facilities.

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lntegration with existent plants is an opportunity to improve the overall system sustainability and environmental impact: • C02 excess from existing Q 1-4 site recov­

ered in Q5&6 site thus reducing C02 emis­sion to environment

• Reuse of Sea Water from existing plants to be used as make up in Q5&Q6 site, avoid the marine environmental impact

• Power and steam integration in Q 1-4 site have taken a key role to cope with the need of improvement of site energy efficiency.

• Control logic and automatic system devel­oped by Saipem have ensured proper func­tioning of all interfaces with existing plants in all operating scenarios thus improving the reliability of the complex.

• New Handling system interfaces implement­ed allow full flexibility with possible use of existing bulk halls, bagging system and Jet­ty.

Saipem's execution of the integration ofthe plants

Saipem developed the design based on the con­tractual requirement and its own experience in the fertilizer field. The execution has been conducted in close co­operation with QAFCO thus sharing of experi­ence implemented in the design. The following are the main features and peculi­arities of the systems.

Electrical Network

The Power Distribution Control System (PDCS) network controls the whole QAFCO plant by means of a dedicated automation system. The peculiarities of the system are:

1) Integration of the existing QI-4 control system with new Q5 and Q6 projects. This complicated step has been realized with a total migration of the existing da­ta base composed by 13000 tags under control of the new PDes servers for a total of 33000 tags. In this way the full

AMMONIA TECHNICAL MANUAL

control and supervision of the entire QAFCO electrical network including the 132kY GIS and 13 (thirteen) electrical substations has been ensured.

2) Revamping of the existing load shedding system (frequency based) with a new load shedding realized with the aim of programmable logic controllers based on "pre-calculated" philosophy. This pre­calculated load shedding philosophy with predefined load groups is a critical strategy to avoid a major power break­down during a disturbance in electrical plant operation such as tripping of a generator. Hence the pre-calculated load shedding function plays an important part in the power distribution control and power generation control strategies. The pre-calculated load shedding constantly monitors the load flow in the electrical network. When there is reason to reduce the load because of a trip of the genera­tion capacity the load shedding will im­mediately re-calculate the load balance considering the generator spinning re­serve and taking into account the ability of the generators to accept step changes.

3) New Power Generation Control system (PGC). This includes one set of dedicat­ed programmable logic controllers for power management and load sharing logic among new and existing genera­tors. The PGC system shall be utilized to maintain system active and reactive power set points when connected to pub­lic utility as well as frequency and volt­age set points for island operations. PGC will include also optimum and automatic load sharing at pTevailing load demands.

4) Control and supervision of the existing and new emergency diesel network. This includes remote periodical maintenance test and back up operation in case of failure of one emergency diesel genera­tor.

5) Control and supervision for synchroniza­tion of the new and existing QAFCO

AMMONIA TECHNICAL MANUAL 250

generators (total of 7 sets) with aim of automatic sequence built into PDeS. This includes auto/manual operations from PDeS HMI.

6) Control and supervision of whole QAFCO complex electrical network. This includes 132kV GIS circuit break­ers including main incomers QATAR from public utility, MY IL Y switchgears operations, load transfer operations, transformer tap changer set point, diag­nostic including alarm and events long and medium term archive.

Sea Water system

The peculiarities of the system are: I) Sea water make-up to Q5 Cooling Tow­

ers has been taken from the return head­ers of the existing Q3 and Q4 plants: re­use of a portion of "hot" sea water (maximum supply temperature 45°C) that nonnally is discharged back to the sea, so avoiding the need for a new sea water intake and for a new sea water out­fall;

2) A multi-cell cooling unit requiring the provision of a pumping system (launch­ing pumps) and pipelines (two parallel 36" make-up lines and two 36" return lines with a length of approximately 5 km with several road crossing and varia­tion in elevation/direction due to con­straints with existing plants);

3) One of the largest multi-cell cooling units (34 cooling cells with a total ther­mal duty of around 1,500 MW);

4) A dewatering system able to completely empty the overall network (both under­ground and aboveground) including pipelines;

5) 110 inches Glass Reinforced Plastic (GRP) underground headers;

6) Biocide dosing system based on bromide combined with Sodium Hypochlorite to ensure a more effective sea water condi­tioning against biological organisms and

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to mmlmlze the environmental impact due to the use of Sodium Hypochlorite.

Power generation

The peculiarities of the system are: 1) integration system between Cogenera­

tion Plants, one Steam Turbine Genera­tor and external Power feed from nation­al network; the integrated system has the capability to provide all nonnal power requirements even in island operation;

2) Integration with steam network through Heat Recovery Steam Generators (HRSGs) installed on Gas Turbine Gen­erators (GTGs), Waste Heat Boilers (WHBs) on Ammonia Plants, Auxiliary Boilers and through steam turbine gen­erator (integration between master pres­sure controller and Power controller);

3) The power system has been conceived so that tripping I outage of anyone of the units (n-l condition for generators, steam turbine generator or external pow­er feed from grid) during normal opera­tion does not affect the production facili­ties; practically the total power failure is not possible

Steam Generation

The peculiarities of the system are:

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I) Steam is generated by a combination of waste heat from gas turbines and auxilia­ry boiler provided the boiler nonnal op­erating load is optimized with the load of the HRSGs to maximize the overall effi­ciency and overall reliability of the steam system.

2) Control steam grid pressure is from any of the HRSGs, the steam turbine genera­tor and the auxi liary boilers.

3) In-depth DYNAMlC SIMULATION STUDY performed during the engineer­ing phase to analyze the response of the steam network in all the possible scenar­ios;

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Waste Water system

The peculiarities of the system are: I) One of the first Fertilizer Plants adopting

Thermal Concentration (multiple effect evaporator, forced circulation type, op­erating under vacuum) for waste water management in order to obtain clean wa­ter to be reused and a brine for solids production (through final crystallization in an evaporation pond) to a periodical disposal.

2) Conceived to maximize the re-use of wa­ter inside the plant also through the re­covery and the treatment of stonn water and of humidity condensate coming from the Air compressors; the resulting clean water is recovered to the multi-cell cooling unit.

Ammonia Storage Tanks

The peculiarities of the system are: 1) These are currently the largest refriger­

ated ammonia storage tanks in the world. 2) Around 5 km of pipelines (two 8" head­

ers) to connect Q5 to the new Ammonia storage Tanks (located near existing Q I Plant) with several constraints related to the routing (roads and existing plants crossing).

Process (Ammonia, Urea and UFC-85 plants)

The Q5/Q6 facilities include the following pro­cess units: • 2 Ammonia Plants of capacity 2,300 MTPD

each, the biggest capacity for plants licensed by Haldor Topsoe

• 2 Urea Plants of capacity 3,850 MTPD each, licensed by Snamprogetti™ Urea Technolo­gy, the largest urea plants worldwide

• I UFC Plant of capacity gS MTPD, licensed by fonner Perstorp Formox, the first refer­ence of Saipem as EPC contractor for this technology.

AMMONIA TECHNICAL MANUAL

Among the major chal1enges faced during the design of Q5 and Q6 Projects, such as the use of strict material and mechanical specification (de­viating from Licensors' standard practice), the following goals set in the contract requirements were driving the conceptual design of the inter­connecting system linking the process units: • High availabi li ty target > 98% • Turnaround of min 1460 days between two

planned shutdowns In order to achieve maximum availability of the complex, the two ammonia plants are independ­ent in terms of process lay-out: all process units required for continuous operation are dedicated to each plant. The reliability of the complex is increased by avoiding common units: a failure of a single equipment is not jeopardizing the production of both plants at the same time. Flare and boiler feed water systems were also dedi­cated to each plant, while other utilities were in­tegrated at complex level.

While the two plants have been designed in or­der to be independent from each other, the de­livery of products is completely interconnected: each ammonia plant is able to feed both urea plants with C02 and ammonia. Cold ammonia to storage is also interconnected. Tie-ins were foreseen during Q5 project design to cater for future installations of Urea-6 (U-6l Plant. The tie-ins were designed in such a way that add-in of U-6 Plant would have been possible without interruption of any of Ammonia-5 (A-5) or Ammonia-6 (A-6) operation. Automatic control and safety system were designed in order to consider the possible different operating modes, either with one or two urea plants running. In particular, the design of the C02 product line was that since the beginning it was possible to feed Urea 5 CO, compressor from both A-5 and A-6 plants. Tie-ins were provided for installa­tion of Urea-6 C02 compressor, as well as for the installation of an additional booster com­pressor, allowing the surplus C02 from existing QAFCO plants to be delivered to the new facili­ties. This lead to an overall reduction of C02

AMMONIA TECHNICAL MANUAL 252

emissions to the environment from the entire QAFCO facilities.

Ti&-in for U6

Tie-in for U6

Figure 1. COl interconnecting scheme before and after implementation of Q6

As far as ammonia product is concerned, since the design phase of Q5 Project the following was envisaged: • Cold ammonia collector to take ammonia

from each ammonia plant and deliver to any of the 2 interconnecting lines.

• Hot ammonia collector to take ammonia from each ammonia plant and each inter­connecting line and deliver to Urea-5 (U-5) plant, with a tie-in for future delivery to U-6 plant.

• 2 interconnecting lines, each sized for full production of both plants, to deliver cold ammonia from ammonia plant to storage and from storage to urea plants.

A detai led analysis of all possible operating scenarios was conducted and the system was provided with all necessary protections such as check valves to avoid back flow of hot ammonia in cold lines and relief valves to protect piping from thermal expansion.

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Figure 2. Ammonia interconnecting scheme

An interconnecting line was added to supply hydrogen from A-5 plant to A-6 and vice versa, thus ensuring hydrogen availability for start-up of one plant while the second is running. The off-spec condensate tank and relevant pump is the only equipment which is common to both units as it is used only during start-up or upsets. However, it is possible from the common tank, located in A-5, to recover the off-spec conden­sate in any of the strippers provided inside each Ammonia Plant. As well as for the two ammonia units, both U-S and U-6 were equipped with strategic and im­portant interconnecting tie-in points.

The two raw materials necessary for the urea production can be independently fed to the sin­gle urea units, without jeopardizing the reliabil­ity of the overall complex.

In particular, C0 2 compressors can be fed inde­pendent1y by an unique integrated C02 grid; Whereas, the ammonia is sent to urea synthesis, either directly through the ammonia synthesis loop or via ammonia storage tank.

These particular features significantly increase the flexibility of the complex and lead to mini­mized production losses by applying different configurations for the supply of raw materials.

In addition to the above, the same process scheme has been applied to other sections in the urea unit: for example in the urea solution re-

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covery unit the facilities to feed/receive the urea solution from each unit are interconnected. This arrangement allows to maximize the production during the granulation unit washing period, by feeding the urea melt to other granulation unit through the interconnecting pipe between the two urea solution tanks.

The UFC-85 plant was designed to cater for the demand of both U-5 and U-6 plants. A tie-in for the delivery of UFC-85 solution to the future U-6 plant was envisaged since the beginning. Be­fore the start-up of U-6, product surplus was sent to the storage tank. A daily tank is provided for each urea granulation plant, whereas the main storage tank has enough capacity to sus­tain prolonged operation of the urea plants even in the event of UFC-85 plant downtime.

C02 system integrated with Ql-4 site

The addition of U-6 Plant of same capacity as U-5 Plant would result in a negative C02 bal­ance at Q5 Site. Therefore a new C02 Booster Compressor (700 MT/D capacity) has been in­stalled in Q 1-4 site, along with the relevant C02 transfer line to allow the transfer of C02 amount required to close C02 balance. The C02 in the main header at Q 1-4 Site is a combination of C02 from all four ammonia plants at Q 1-4 site. Control logic ensure adequate protection of the C02 cross connection at Q 1-4 Site ensuring that the four Ammonia Plants in Q 1-4 site are work­ing with the adequate battery limit pressure. Due to the significant di stance between Q 1-4 site and Q5 and Q6 site, the C02 transfer line may be subject to significant heat losses, poten­tially leading to condensates formation. To avoid a heavy mechanical design of the line, due to slug flow, it was decided to provide an elec­trical heater on the C02 Booster Compressor discharge and to install several liquid pots along the intercormecting line.

The correct C02 flow split between U-5 and U-6 plant, is performed by means of two pressure controllers, one for each main C02 Compressor,

AMMONIA TECHNICAL MANUAL

installed on relevant suction lines. These pres­sure controllers ensure that the adequate pres­sure level is always maintained on suction lines, independently on Ammonia and Urea plants re­quired loads.

QS and Q6 Handling Facilities

The overall Q5 and Q6 Urea Handling System basically involved three major operating areas consisting of: • Q5 and Q6 production plant Area • Interconnecting Area out of the plant fence • QAFCO port site Jetty- I and Jetty-2 Area at

approx. 3.0 Km far from Q5 production plant

Additional interconnecting facilities were pro­vided to allow link to the existing Bulk Halls and bagging plant at QAFCO site.

The main technical challenge of the project was the design of the two long intercOIll1ecting pipe conveyors for a distance of nearly three (3) km which provide the link between the new Q5/Q6 site and the existing QAFCO site.

To ensure the safety across a number of obsta­cles along the run-way represent a challenge which had to be overcome with no alterations of the existing fac il ities.

The pipe conveyor is a relatively new type of belt conveyor. It utilizes a special conveyor belt that is wrapped into a circle or "pipe" shape af­ter being loaded with material. The pipe enclo­sure is maintained by using idlers, which on a conventional conveyor are normally used to form a trough for the belt. At the discharge point the belt is unwrapped and the material is dis­charged over a pulley in the conventional way. The return run is also formed into a circle.

The pipe conveyor is very "clean" environmen­tally, since the load and the return run are totally enclosed. The pipe conveyor is compact in cross section, and can negotiate horizontal curves

AMMONIA TECHNICAL MANUAL 254

with a much shorter radius and more simply than a conventional belt. QAFCO pipe convey­ors run at high elevation, crossing public roads, and passing-through existing facilities at QAFCO site

For each one of the pipe conveyors, the design incorporates horizontal curves with a radius of 400 meter. Both Pipe Conveyor run parallel to each other for 1,500 meters, above the interconnecting pipe-rack while remaining length are elevated in bridge gantry sections supported by trestles.

Each one of the pipe conveyors have the fo llow­ing main technical characteristics • Capacity: 1,100 tonlh • Belt width: 1,800 mm • Belt pipe diameter: 500 mm • Belt speed: 3 mls • Length ofQ5 pipe conveyor: 2,790 m • Length ofQ6 pipe conveyor: 2,660 m • Drive power: No.3 motors of 250 kW each,

two drives at the head-end and another drive at the tail end of the conveyor

The second main technical challenge was the fu ll integration between new Q5 handling sys­tem and new Q6 handling system with existing QAFCO handling, storing and shipping faci lities providing the highest operating flexibility of the overall QAFCO handling. It is possible to trans­fer new Q5 and Q6 urea productions to either of the new bulk storage, to existing bulk storage. to existing and new ship-loading facilities at jetty­I and jetty-2.

Challenges encountered during the Q6 construction phase while Q5 was in commission ing and start-up

The execution of Q6, mainly located inside Q5 area, required a detai led management of the se­quence of all construction activities and relevant safety implications. Below we report the main

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challenges encountered that required special at­tention:

•

•

•

•

•

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06 area segregation. U-6, bulk hall and Co­gen-3 area were physically segregated with barriers and gates. A dedicated traffic plan and access for construction workers were implemented in order to avoid any intrusion in Q5 area (for which a permanent badging system was in place). Cooling tower extension. While Q5 Cooling tower was in operation, it was required to provide the basin extension for Q6. The ac­tivities were planned through use of water stop and temporary additional barriers to perform construction activities while the Q5 basin was in operation. Cogen area extension (additional train). The main challenge was the excavation nearby rack under operation and the protection of existing live gas line. For the excavation the use of shoring was mandatory while the use of double layer of scaffolding on top of gas line was enforced to ensure protection from any potential falling objects. Moreover for site erection a tower crane was used to min­imize foot print and interference with other existing units. C02 compressor installation. Due to the physical location of this compressor in run­ning A-6 plant, the installation was per­formed from the top with remov­aVreinstallation of compressor house roof. During construction the compressor house was physical segregated with barriers to avoid interference with on-going Q5 opera­tion. New 3km belt conveyor installation. This equipment was in part located on the same rack supporting the existing conveyor in op­eration. Protection of the existing belt and increasing of surveillance were mandatory. Moreover tie ins of the new belt conveyor with the existing Ql-4 bulk halls were per­formed while in operation so a dedicated procedure was developed with specific HSE

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requirement and permits agreed with opera­tion.

Fig 3. Interconnecting area, Jun 2012

• Upgrade of existing energized substation. The activities consist of the upgrade and in­stallation of a new cabinet in the existing live substation and require, in addition to the normal safety precaution foreseen, the use of specialized vendor on site to perform the ac­tivities.

• Execution of around 300 process tie ins with existing plant. A tie in schedule was devel­oped to monitor each single tie in, with a dedicated procedure/permit for each one. A dedicated team was appointed for the man­agement only of this critical activity.

In addition to these specific activities, the gen­eral management of construction required a par­ticular focus on HSE aspect so that:

• All workers were wearing long sleeves clothes and ammonia mask.

• The construction supervisor was selected with dedicated training/interview to work for Q6 due to criticality.

• HSE passports were used to monitor and re­fresh the training status of supervisors and workers.

• It was developed method statement for each and every construction activities in order to

AMMONIA TECHNICAL MANUAL

Fig 4. U-6 and granulation, Feb 2012

Main challenges and the effective management for commissioning and start up

Q6 Project Sea Water (SW) make up pump: • Hot SW is pumped from outfall ofQ3/Q4 to

the Q5 facilities as make-up to the cooling tower and to the desalination unit. by means of two SW launching pumps, one running and one stand by. After addition of Q6, the water design flow rate had to be increased from 12,350 m3lhr to 14,000 m3/hr, requir­ing new size of impeller. To avoid interrup­tions of Q5 operation. SW launching pumps were handed over to maintenance one by one, after positive isolation. Proper instruc­tions/operating procedures were prepared in case of tripping oftbe running pump,

Qafco-S

Urea-S Bulk hall e 100000 MT

Jetty· ! 1000 MT/hr

Urea-6 Sulk hall F 17SOOOMT

Q6 Project Closed Cooling Water (CCW) sys­tem: • For Q6 plant two CCW pumps and four

plate heat exchangers were provided to meet the additional requirement of 14,800 m3/hr. New underground and above ground piping network was laid for U-6 plant. The above ground carbon steel piping was cleaned by line blowing with cardboard rupture sheet. After that a strainer at common outlet of U-6 battery limit was installed and water circula­tion was established at low rate. During this period the pressure drop across the plate heat exchangers was monitored and the flushing was completed in U-6 without af­fecting the running units of Q5.

Q6 Project Material Handling: • One bulk hall with 175,000 MT capacity

with reclaimer and the export Urea to exist­ing facilities of QAFCO bulk halls CID and jetty-I. The installation of conveyers, chutes and diverters in the existing bulk halls CID was carried out with proper coor­dination with Q3/Q4 operating staff and job was carried out successfully without creat­ing problem to running units Q3/Q4. The running signals of the existing conveyors of Q3/Q4 were connected with new system of Q6 PLC.

Q afco3/4

Bulk hall C

J(!lty· 2

Bulk h all 0

Qafco-6 Qafco-S

Figure 5. Project material handling arrangement

AMMONIA TECHNICAL MANUAL 256

_ Qafco-6

o Qafco3/ 4

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Q6 Project Steam Blowing • Additional steam network for Q6 was re­

quired. Due to the over capacity available in the Q5 steam system, 80 Tlhr were used to carryout steam blowing in Urea plant of Q6. Steam blowing activity was completed suc­cessfully without any upset to the steam sys­tem of Q5 site thanks to proper coordination with operation.

Q6 Project C02 Booster compressor: • Excess C02 from existing Q 1-4 site units is

utilized for Urea production in Q6. C02 booster compressor and relevant control sys­tem was provided at Q3 site. C02 was taken from the existing units of QAFCO to carry out the blowing of the 3 krn discharge pipe­line and the testing of the compressor. The commissioning of this unit was carried out with proper coordination.

Q6 Project Sea Water cells extension: • Six additional sea water cooling cells were

installed to meet the SW and CCW water requirement of Q6. During Q5 design phase, a gate was foreseen to separate Q5 and fu­ture Q6 basins. After construction of Q6 ba­sin and cooling cells, the gate was removed and commissioning was done successfully. During construction proper care was taken to avoid entry of foreign material into the basin.

Q5 Project GTGIHRSG for existing QAFCO units: • Two new gas turbines 29 MW each and

HRSG of 150 Tlhr each are installed in Q I-4 site to scrap some old open cycle GT -so First one GT was commissioned and power was synchronized to grid of QAFCO. After sta­ble running, some of the open cycle GT-s were stopped. The second GT was also commissioned and the remaining open cycle GT -s were stopped. The HRSG commis­sioned one by one and the steam blowing was carried out up to tie in point of Q 1-4 site. Once the target plate was clear at the tie

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in point, steam was lined up to the existing users of QAFCO site. The control of GT-s are provided in Q5 site utilities control room and the HRSG control is provided in Q3 control room for easy operation. All the ac­tivities were earned out with close coordina­tion for existing Q 1-4 site staff.

Conclusion

The Q5 and Q6 projects presented a number of technical, logistical and other challenges that was dealt with by team work between all the parties involved in the execution of these pro­jects. Proper assignment of resources to manage the whole tie-ins from the early phase of execution involving all disciplines, proper coordination between Contractor and Company to plan activi­ties of integration during the allowable shut down of running plants, early identification of challenges in design stage are key factors to achieve successful results of realizing a robust and safe integrated scheme,

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