Safe Start-Up of the ENPC Complex under Challenging ... · struction and commissioning of a...

Safe Start-Up of the ENPC Complex under Challenging Circumstances

Safety is always in the focus during start-up of a fertilizer complex. This includes occupational safety for the personnel working on site and process safety to ensure that the process does not generate any

hazards.

This paper gives examples of how safety was ensured for the recent commissioning of the Egyptian Nitrogen Products Company (ENPC) ammonia / urea complex consisting of two trains in Egypt

between 2011-2016.

The project has a difficult history with a relocation and several interruptions of the site activities for external reasons. In November 2011 the activities on site had been stopped with all access to the

facility closed. As a consequence the project activities on site had been suspended for 27 months until February 2014.

After resuming of the site activities in February 2014 in summary both trains were started

successfully with all parameters within specifications. Achievement of Provisional Acceptance was in November 2016. Thanks to the strong safety precautions and carefulness during all construction and

(pre-) commissioning activities, no fatalities occurred during the complete project period between 2007 and 2016. The gained experiences are highly relevant in terms of proper preservation and

maintenance of the safe and reliable operation of ammonia and urea plants.

Tarek El Hawary thyssenkrupp Industrial Solutions AG

Introduction afety is an important aspect during con-struction and commissioning of a fertilizer complex. Safety must not be sacrificed for reducing the project duration or cost. It is

common that in some areas of the plant construc-tion is still ongoing while others are already tak-en into operation, e.g. the utility units. This leads to a situation where potentially the risks of a con-struction site and those of an operating plant (high temperatures, high pressures inside the ves-sels) can add up. It even can get worse, if con-struction and commissioning staff do not proper-ly communicate with each other and are not aware of the risks going out from the other party.

In particular, the risks caused by operation are sometimes not directly evident to the construc-tion staff, for example when a pipe surface which was always cold, from one day to another sud-denly is hot, without anything visibly being changed in its vicinity. Of course, such risks must be reduced, and some tools are presented here at the example of one of the recent projects of thyssenkrupp Industrial So-lutions (tkIS, formerly known as ThyssenKrupp Uhde). tkIS is a leading ammonia licensor and LSTK (lump sum turnkey) contractor for fertiliz-er and other plants. In the project discussed here, tkIS was acting as an EPC contractor, which means it had the responsibility for engineering,

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272017 AMMONIA TECHNICAL MANUAL

procurement, construction and also for the com-missioning and start-up of the complex.

ENPC Project In 2016, the two train ammonia / urea fertilizer complex ENPC, owned by ENPC (Egyptian Ni-trogen Products Company) was successfully commissioned. The complex is located in New Damietta (Egypt) near the Mediterranean Sea (see figures 1 and 2). It has been erected at a de-veloped site, next to the existing ammonia / urea plant, referred as MOPCO (Misr Fertilizer Pro-duction Company), which was also executed on lump sum turnkey basis by tkIS in 2008.

Figure 1: Location of the ENPC complex in northern Egypt. The ENPC complex consists of: • 2 x 1,200 t/d ammonia plant (Uhde process

with Johnson Matthey catalysts, UOP Ben-field CO2 Removal)

• 2 x 1,925 t/d urea plant (Stamicarbon synthe-sis and Stamicarbon granulation).

• all offsite and utility facilities, including 72,500 t urea storage.

The ammonia plant can be operated “balanced” to the urea plant – that means all ammonia can be

converted to urea; in this case there is no excess ammonia in normal operation.

Project History

In total the ENPC project had a running time of 9 ½ years from effective date (date of contract signature) until the achievement of provisional acceptance (PAC). Three stoppages and one site relocation in between were the main reason for the long project time. After the achievement of provisional acceptance the project commenced into the clearance phase for final acceptance (FAC) achievement. Date Event Add.

Information 19.04.07 Date of Contract 08.07 1. Site Stoppage Political

Interference 12.07-01.08 2. Site Stoppage Political

Interference 04.08-08.09 1st Suspension

3rd Site Stoppage Relocation from “Old”-Site to current Site within Harbor of Damietta

Political Interference

15.10.09 Recommencement Date (New Site)

10.11.11 2nd Suspension Civil Unrest 17.02.14 Suspension Lifting 08.06.-15.06.15

First Ammonia and Urea Product Train 1

18.12.-26.12.15

First Ammonia and Urea Product Train 2

03.16 Performance Test Train 1

05.16 Performance Test Train 2

13.11.16 Provisional Acceptance (PAC)

28 2017AMMONIA TECHNICAL MANUAL

Figure 2: ENPC ammonia / urea complex (view by night on train 1 including ammonia storage tank and the adjacent New Damietta Harbor – picture taken from urea synthesis train 2)

Site conditions

During the engineering phase, the whole plant was subdivided in subsystems to allow for better coordination at the transition from construction to pre-commissioning. A subsystem is a set of piping, equipment, instrumentation and other items which is handed over together from con-struction to pre-commissioning. Typically, around 3 to 10 subsystems form one process unit. Pre-commissioning comprises the preparation of the mechanically erected plant for the start-up, which is cleaning by flushing and blowing, tests in cold condition, catalyst filling and similar ac-tivities. Organization and planning of the pre-commissioning was part of tkIS construction re-sponsibility. tkIS staff on site prepared the pre-commissioning procedures for most sub-systems. Like in all recent tkIS projects, the commercially available data base system ICAPS (Integrated Commissioning and Progress System) was used to plan and to track the status and activities for

each subsystem. The usage helped tkIS together with ENPC as client to organize the transition from purely mechanical construction to pre-commissioning. In the special case of the ENPC project with the suspension period in between, the ICAPS systems was also useful to track back the achieved construction status before suspen-sion. In addition to the monitoring of the con-struction activities, the ICAPS was also used to track the (pre-) commissioning activities for a full transparency with the client and in order to align with the project time schedule. When all pre-commissioning steps in a subsys-tem in train 1 were completed, it was prepared for the next steps, namely commissioning and start-up. The complicated project history and the situation on site after lifting of the suspension in combination with the ongoing parallel construc-tion activities in train 2 increased the safety risk on site. Therefore a so-called Pre-Start-up Safety Review (PSSR) was done using certain steps in-volving all relevant disciplines.


Challenges during the (Pre-)Commissioning

Commissioning and start-up is in any case a critical phase in the plant lifecycle. The main challenge of the (pre-) commissioning for the ENPC project was a 27 month project suspension due to civil unrest in Egypt as mentioned above.

First (pre-) commissioning phase and project suspension

The first (pre-) commissioning before the sus-pension, started in August 2011 and was inter-rupted shortly after in November 2011, when all activities on site had to be stopped. Several sub-systems were left filled with water or left open to seashore atmospheric conditions with high salt contents in the ambient air for the complete sus-pension period from November 2011 until Feb-ruary 2014. Examples are: • The cooling water system filled with untreated

town water for initial flushing. • The demineralized water system was partly in

operation. • The boiler feed water system partly filled.

Parts of the system open to seashore atmos-phere.

• Fuel gas and Reformer feed and mixed feed system open to seashore atmosphere. Water from air humidity condensing inside the pip-ing and causing corrosion.

• Sub-systems filled with water resulting from interrupted hydrostatic piping tests.

• Several tanks including the 30,000 mt ammo-nia storage tank filled with water for pre-commissioning purposes and for hydrostatic testing.

• The ammonia converter (train 1) with in-stalled ammonia converter cartridge left open from the top without cover. Catalyst filling preparations were ongoing and to be started soon.

After tkIS’ return to site in December 2011, preservation procedures were prepared based on a premise for the stoppage of all site activities for a few months. Since it was not possible to do preservation measures on site due to the civil un-rests outside the plant, smaller preservation measures were implemented as much as possible. Second (Pre-) Commissioning Phase – July 2014 to November 2016 After the tkIS’ return to site in February 2014, inspection, preparation and first construction ac-tivities took place between March and July 2014. In July 2014 the (pre-) commissioning activities resumed with the interconnecting system be-tween both trains and the plant and instrument air system of train 1. For the interconnecting system no special activities were necessary, since the system was preserved under natural gas during the suspension period due to lack of possibility for a safe relief of the natural gas. In summary the (pre-) commissioning and start-up phase for train 1 was a success without major safety observations with all parties following the strict safety protocols. All pre-commissioned sub-systems were inspected carefully during the preparation of the pre-commissioning steps in-cluding all relevant disciplines, e.g. QA/QC, pip-ing, instrumentation and static equipment. Major rotating equipment, for example the syn-thesis gas compressor, were specially inspected and repaired after the suspension including the vendor specialists, specialists from tkIS and from ENPC. Found defects were repaired during the pre-commissioning phase immediately by utilizing the corresponding parts from the identical second train, if they were in a usable condition. During the (pre-) commissioning of the first train the second train was still under construction, which allowed the usage of installed parts as spare parts. There was enough time afterwards to order new parts for train 2. In many cases parts for


both trains had to be ordered due to damage or malfunction resulting from the 27 months sus-pension. This was done in close cooperation with ENPC. In general the (pre-) commissioning activities were delayed due to the ongoing inspections of the sub-systems and remaining construction ac-tivities. Hydrostatic tests for several sub-systems had to be repeated as well as inspections for welding seams like hardness values. Special problems occurred also during the con-struction of the steam systems, with missed tar-gets for hardness values or mismatches in the se-lected piping material by the subcontractors. This had been detected by close monitoring by the QA/QC department using Positive Material Iden-tification (PMI) method. The handover of the steam system from the construction to the com-missioning department for steam blowing pur-poses in train 1 was delayed for several weeks as a result. Similar problems were found in the in-terconnecting steam system between both trains, which also caused a delay of several weeks for the steam blowing of train 2. In summary the (pre-) commissioning activities for the gaseous sub-systems in train 1 went straight forward successfully. Major damages were mainly detected for control valves, flanges and gaskets, e.g. lens gaskets. Whenever possible the damages parts were repaired, e.g. resurfacing of lens gaskets. Air blowing had been repeated several times to remove all the accumulated dirt and rust in the system. Experiences from other projects have shown that the required effort to clean the piping by air blowing and water flush-ing after suspension was approximately two to three times higher than for projects executed in conventional time frames (3-4 years). For the water containing sub-systems the situa-tion was different. Since several of the sub-systems were filled with water during the sus-pension and were partly open to the seashore at-mosphere, a much higher amount of damage was

found during the construction and (pre-) com-missioning phase. Especially carbon steel piping such as in the cooling water system was heavily affected. Several parts of the piping had to be re-placed after intensive inspections. Beside the cooling water piping, the ammonia refrigeration system also showed a high amount of corrosion. From the (pre-) commissioning phase up to the production phase, leakages in the piping of the cooling water system occurred regularly, which often caused forced shutdowns of the plant (or parts of it). Damaged parts had to be replaced. For the cooling water system, which contains media with no hazard and low pressure, the de-scribed approach had been evaluated with no safety risk and as the only practical approach due to large number of sub-systems involved (see Figure 3).

Figure 3: Replaced corroded pipe from the cool-ing water system train 1 Unfortunately during the commissioning phase, while synthesis gas was introduced into the am-monia synthesis loop under pressure, a leakage in the gas cooler downstream of the gas/gas heat exchanger was detected. The gas cooler serves the purpose to cool the ammonia containing syn-thesis gas by cooling water before it enters the cold exchanger to separate the major part of the ammonia product. The gas cooler is a shell and tube heat exchanger. After the detection of the leakage the ammonia synthesis was immediately depressurized and purged with nitrogen over


several days with continuous hazardous gas mon-itoring. During the following inspection of the heat ex-changer by borescope and eddy current several leakages in the tubes were detected resulting in the urgent replacement of the complete gas cool-er. Since the fabrication of a replacement heat ex-changer would take several months, the complete project schedule would have been jeopardized. By a lucky coincidence a replacement gas cooler with the same specifications was found at Abu Qir Fertilizers in Alexandria (Egypt) and because of the good cooperation between all companies, it was quickly allocated to ENPC. The two ENPC plants are two out of nine nearly identical plants built by tkIS in Egypt since 1998. The replacement of the gas cooler was executed in a very short period of 7 days considering the difficulty of keeping positive nitrogen in the ammonia catalyst beds and cutting the attached piping to the heat exchanger. A detailed safety analysis including a safety area with limited ac-cess was implemented around the heat exchang-er. During the replacement of the heat exchanger all safety rules were followed strictly with no safety incidents or near misses. In summary it was a remarkable effort considering the time crit-icality and difficulty of the job. For the ammonia refrigeration system, the situa-tion was quite different. During the (pre-) com-missioning phase leakages in the sub-systems of the ammonia refrigeration were detected. On the contrary to the cooling water system, it was not possible to replace affected parts of piping sys-tem one after another later during operation since the operating media is hazardous ammonia. As a consequence the affected sub-systems were care-fully emptied; inspected and corroded parts were exchanged. Since it was not possible to inspect the complete ammonia refrigeration in detail due to its size and the fact that most of the system had already been insulated by cold insulation, a

job safety analysis had been executed in which it was decided to implement a safety area around the ammonia refrigeration system (including af-fected systems like the ammonia synthesis loop). The access to the safety area was for authorized people only. During the initial ammonia filling of the refriger-ation system and the start-up of the ammonia re-frigeration system the plant was evacuated and all points were observed over weeks to detect any eventual leakages and to detect possible de-fects in the piping. Fortunately, except for the previous found leakages, no additional leakages had been found. The safety area around the re-frigeration had been kept for longer time period until the plant was in a steady and stable opera-tion mode. In any case even during the later (pre-) commissioning phase of train 2, additional fire hoses, cubicles and additional safety equipment were stored around the safety area in case of any ammonia leakages. In addition to the found damages in the mechani-cal systems of the plant resulting from the sus-pension period, also the stored catalyst material (see figure 5) and packing material showed a lot of corrosion signs (see figure 4). Especially for the Primary Reformer catalyst and for the pack-ing material of the CO2 Removal Unit, the mate-rial had to be spread out in wide area and sorted manually.

Figure 4: Corroded Packing material for the De-sorption Column of the CO2 Removal Unit


The catalyst for ammonia synthesis converter (iron) was baked together after opening of the storage drums. But it was still possible to load the catalyst normally and in summary the catalyst of the ammonia synthesis was in a good condi-tion and showed a good performance later during production phase.

Figure 5: Deposits on the Primary Reformer Catalyst The catalyst reduction for the low temperature shift reaction in the CO conversion as well as the catalyst reduction of the ammonia synthesis catalyst for both trains were supported by specialist from Johnson Matthey Catalysts during the commissioning phase. Shortly before starting of the reduction of the ammonia synthesis catalyst in train 1, several leakages in the ammonia synthesis loop and at the synthesis gas compressor occurred. Especially damaged lens gaskets surfaces of quench valves directly at the converter pressure shell caused several delays due to the complicated remachining of the surfaces at elevated heights. Therefore the ammonia synthesis loop had to be depressurized and purged over several days with continuous gas monitoring. The whole area was barricaded during this time period with access for authorized personal only. Also, a job safety analysis and detailed evaluation was completed before start of repair activities. After a delay of several weeks, finally the reduction of the ammonia synthesis catalyst was sucessfully finished and the plant proceded into

normal production. A few days after the first ammonia product was achieved, the first urea in train 1 was produced. Unfortunately in the timeperiod of the (pre-) commissioning activities for train 2, while train 1 was already producing ammonia and urea, a leakage in the train 1 waste heat boiler of the ammonia synthesis loop was detected. The leakage was detected by an increase of the conductivity of the waste heat boiler blow down. As a consequence the plant was shutdown shortly afterwards and the complicated repair procedure, supported by the vendor specialist, was initiated. Due to the high risk potential of the job, a job safety analysis was previously prepared including a complicated purge procedure to keep the ammonia synthesis free of combustibles (e.g. hydrogen) and to keep the ammonia converter under nitrogen to prevent oxygen coming in contact with the reduced iron catalyst. After repair of the waste heat boiler, the plant went smoothly back to production.

(Pre-) Commissioning of Train 2

The (pre-) commissioning of the second train started shortly after the first train commenced into production. By that time the first sub-systems were handed from the construction department to the commissioning department. In general after the project suspension had been lifted, the priorities were clearly set to finish construction activities in train 1 first due to the higher exisiting progress from before suspension. The construction activities for train 2 were intensified after train 1 was already further progressed in the commisioning phase. In general during the (pre-) commissioning and start-up phase of train 2 fewer problems occurred compared to train 1. One of the chief causes for fewer problems in train 2 were clearly the higher number of new parts ordered after lifting of the suspension. As mentioned before, a big number of the installed parts in train 2 were used in the (pre-) commissioning of train 1. In addition only a minor number of the sub-system contained


water from hydrostatic tests during the suspension period, so in general less mechanical damages compared to train 1 were found. As an additional help during the (pre-) commissioning of train 2, the running train 1 was used as a backup for steam and synthesis gas via the interconnecting network. The interconnection helped during several upsets of the auxiliary boilers either in train 1 or train 2. Another example for the usage of the interconnecting network between the two plants was the reduction of CO Low Temperature Shift in train 2 by using hydrogen containing synthesis gas from train 1. In December 2015 shortly before the intended start of the reduction of the ammonia synthesis catalyst of train 2, a tube rupture inside the train 2 auxiliary boiler occurred, which led to a forced shutdown of the plant. The refractory inside the auxiliary boiler furnace was damaged by the water flooding into the firebox. In the inspection afterwards the refractory itself showed evidence of pre-damage resulting from the suspension period. As a result, the escape of the water coming from the damage tube through the burners inside the furnace chamber required the refractory to be replaced. The refractory was recast following the advice of vendor specialists with matching refractory material. The reduction of the ammonia synthesis catalyst was started indepedently shortly after the plant was restarted with auxiliary steam from train 1. The repair of the auxiliary boiler in terms of replacing the damaged tube and the refractory inside the furnace was done under strong safety precautions, since the logistics for the repair and the repair itself in a confined space were done in a living plant. In December 2015 first ammonia and urea were produced in train 2, followed by several tests and adjustments for both trains. The performance acceptance tests for both plants were finally

conducted in spring 2016. A detailed overview of the (pre-)commissioning for both trains in details from the restart after the suspension in 2014 until the achievement of Provisional Acceptance (PAC) in 2016 is shown in a timeline in Figure 7.

Feedstock

One of the major challenges during the complete (pre-) commissioning and operation phase of both trains were the several interruptions of the natural gas supply as feedstock. This resulted several times in a complete stoppage of all start-up activities, which require natural gas for several days up to weeks and a high frequency of starting and stopping of the plant in short time distances. A high frequency of starting and stopping of the plant leads to a suffering of the equipment and piping, which on the other hand might lead to unwanted plant shutdowns due to newly formed defects.

Figure 6: Damaged Natural Gas pipeline A high frequency of starting and stopping of a plant as well as stopping a plant for a longer time, e.g. several weeks, is also a safety challenge, since every start-up combustible natural gas is reintroduced into the plant, with all necessary precautions in terms of blinding and isolation procedures. Maintenance activities in between need to be coordinated carefully in terms of purging, gas testing and isolation. Live systems need to be marked according to procedures and involved personal needs to be


informed and to be more careful. Therefore in such cases a detailed permit system including isolation procedures with double check by the commissioning staff and the client personel are helpful to overcome such challenges. The reasons for the interruption of the natural gas feedstock were different, reaching from problems in the natural gas grid, to acts of violence, to the natural gas infrastructure outside the ENPC

complex battery limit. As an example in January 2016 the natural gas pipeline, which provides natural gas to the ENPC complex, among others, was hit by an explosion and heavily damaged (see Figure 6). This led to a forced shutdown of both ENPC plants for nearly four weeks until the pipeline was repaired and rerouted from above ground to the underground and protected by this way safe against violence.

Figure 7: Timeline of the (pre-) commissioning phases for both ENPC trains from restart of the (pre-) commissioning after suspension lifting in 2014 until the achievement of Provisional Acceptance in 2016

Specialties

Beside the major project challenges described above, tkIS also used new improved techniques during the commissioning phase of the ENPC project in order to increase efficiency and to safe time. For example for the catalyst filling of the ammo-nia converter a new method was used instead of the conventional known method by loading the catalysts with hoses or buckets manually and to

vibrate the catalyst bed afterwards by pneumatic vibration devices. The new method uses multiple catalyst distribu-tion cones, which are arranged above the catalyst bed in a circular way (see Figure 8). For the fill-ing the catalyst is stored in a hopper located at the top of the converter with connections at its bottom to each catalyst distribution cone via a special distribution device.


Figure 8: Catalyst distribution cone inside the catalyst bed The new patented catalyst filling method was successfully used for the first time during the ENPC project. The desired catalyst densities were achieved by using the new method with less effort and in shorter period. Compared to the above described conventional catalyst loading method, the cata-lyst loading time could be shorted by 3-4 times. With the positive results from the ENPC project, the new method is foreseen to be used in all pro-spective ammonia catalyst loadings done by tkIS.

Tools Next to a PSSR and the intensive use of the commissioning and construction permits, which have been described already, there are other sim-ple tools used to ensure safety during plant start-up.

“Live” Systems

It has been mentioned in the Introduction al-ready, that it is a critical condition when the pure construction site turns into a partly operating plant. Operation and construction must each show courtesy to the other party for the benefit of the whole project.

While construction works can easily be noticed by the commissioning team, it is more difficult for the construction worker to notice that a cer-tain system next to his working place has turned into operation. Construction activities which can come in conflict with (pre-) commissioning are those at the end late like painting and insulating. They involve a high number of persons which are not familiar with the commissioning activi-ties but which are moving around in pipe racks and other places, close to possibly hot pipelines. Preferably of course, construction work next to operating systems (and that could also be steam or air blowing) should be avoided and the area should be barricaded. If this is not possible, it is important to inform the affected workers. This is done by Livening-up Notice. This is a notice de-claring that a certain subsystem is going to be taken into operation. For the ENPC project this was done directly by the site safety department, who had been in-formed by the commissioning team in a daily commissioning meeting in advance. The site safety department communicated the information daily to the subcontractors for their daily toolbox meetings. Precondition is of course a successful PSSR. Information in the Livening-up Notice is, among others: • number and description of the subsystem • type of activity (blowing, operation, etc.) • location, indicated on a plot plan The last point is important because construction thinks in construction units in plot plans, while commissioning thinks process units in P&IDs. Further important aspects are: • standard format • standard distribution (among others, to all

subcontractors on site)


It is issued by the commissioning team and it is accepted and by the construction and safety de-partment. It can be put up on the bulletin board in the site office containers for everybody’s infor-mation or communicated in daily site meetings between all involved parties, like construction, commissioning and safety. In the ideal world, each subcontractor would convey this information to his staff in the affect-ed area of the plant. When one cannot fully rely on this, marking the live system in the field is the option to bring this information directly down to construction worker in the field. It is done by putting stickers or rope on piping and equipment which is live, preferably on the pipes close to ladders, on vessel manholes, on valves etc. Al-ternatively areas can be barricaded and access only by special permits, which can be only grant-ed by the commissioning team.

Internal communication

It is helpful when there are people in the com-missioning team speaking the language of the client and the construction staff. This was the case for the ENPC project, where communication in Arabic allowed to avoid misunderstandings. This shall not diminish the role of English as the project language and the language of the Operat-ing manual. But it opens a path • for the commissioning staff to get feedback

for the ordinary construction worker or opera-tor (who might not be fluent in English) to quickly check whether instructions have been understood;

• for the client’s staff to directly ask if they have questions.

Same as for the Livening-up Notice, good com-munication avoids conflicts and risk from lack of information and thus promotes safety at work. Worth to mention in this context is the services by Johnson Matthey, ThyssenKrupp Industrial Solution’s alliance partner for ammonia plant catalysts. Commissioning staff by Johnson Mat-

they is present in all projects for catalyst reduc-tions and startup activities. Thanks to their per-manent presence in all regions in the world, they can send staff for start-up assistance which speaks the language of the client and in many cases is already known to them from the catalyst replacement business for the client’s other plants.

Summary In summary both ENPC trains were started suc-cessfully with all parameters (e.g. energy and water consumption, emissions) within specifica-tions. Thanks to the strong safety precautions and carefulness during all construction and (pre-) commissioning activities, no fatalities occurred during the complete project period between 2007 and 2016. From September 2007 until November 2016 to the total project working hours came to 35,919,571. During the project duration the total number of Lost Time Injury Cases (LTI) was five; all during the construction phase mainly fractures, which were investigated in detail with the result of more frequent safety trainings and more safety personal on site by the subcontrac-tors in their responsibility area. Independently the site safety departments of tkIS as well as of the client were strongly represented on site. Since the last Lost Time Injury in August 2014 a total number of safe working hours of 8,951,778 has been achieved. The gained experiences during the ENPC project are highly relevant in terms of proper preserva-tion and maintenance of the safe and reliable op-eration of ammonia and urea plants.


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