safe start-up of ammonia / urea plants under challenging …/fileser… · tion of the mechanically...

Safe Start-up of Ammonia / Urea Plants 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 the tools used to ensure safety for the recent commissioning of two ammonia / urea complexes in 2013. This includes both organizational and technical activities during

engineering, pre-commissioning, commissioning and start-up. It also highlights the importance of good collaboration with the end user and the specialist support from vendors such as Johnson

Matthey and licensors.

An unplanned situation occurred in one of the projects, when the first train of the complex had to be shut down after a few weeks of operation, because the production permit by the authorities was not

available. The paper describes how these circumstances were handled and how the client was supported. The plant was out of operation for twelve months. Thanks to good preparation, the re-start

went extremely smoothly, after a permit was available.

Klaus Noelker ThyssenKrupp Industrial Solutions AG

Introduction

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

common that in some areas of the plant con-struction is still ongoing while others are al-ready taken into operation, e.g. the utility units. This leads to a situation where potentially the risks of a construction site and those of an oper-ating plant (high temperatures, high pressures inside the vessels) can add up. It even can get worse, if construction and commissioning staff

do not properly 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 construction staff, for example when a pipe surface which was always cold, from one day to another suddenly is hot, without anything visi-bly being changed in its vicinity. Of course, such risks must be reduced, and some tools are presented here at the example of recent projects of ThyssenKrupp Industrial Solutions (TKIS, formerly known as ThyssenKrupp Uhde). TKIS is a leading ammonia licensor and LSTK (lump sum turnkey) contractor for ferti-lizer and other plants. In the example projects

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1092014 AMMONIA TECHNICAL MANUAL

discussed here, TKIS was the technology pro-vider, but was not responsible for construction.

FERTIL 2 Project

The Project

In 2013, the ammonia / urea fertilizer complex FERTIL 2, owned by FERTIL (Ruwais Fertiliz-er Industries), a subsidiary of the Abu Dhabi National Oil Company (ADNOC), was success-fully commissioned. The complex is located near Ruwais at the sea (see Figures 1 and 2). It has been erected at a developed site, next to the existing ammonia / urea plant, now referred to as FERTIL 1.

Figure 1: Location of the plants mentioned in the text.

FERTIL 2 consists of: 2,000 t/d ammonia plant (Uhde process with

Johnson Matthey catalysts, BASF aMDEA CO2 removal)

3,500 t/d urea plant (Stamicarbon synthesis and UFT granulation)

all offsite and utility facilities, incl. 100,000 t urea storage and urea shiploading

The ammonia plant is “balanced” to the urea plant – that means all ammonia can be convert-ed to urea; there is no excess ammonia in nor-mal operation. Main contractor for this project was Samsung Engineering from Korea. Scope of ThyssenKrupp Industrial Solutions (then Uhde) was the basic engineering for the process plants and procurement and detail engineering of the proprietary items. Remaining supply, engineer-ing and construction was done by Samsung.

Challenges during Commissioning

According to the contract, TKIS’ role in pre-commissioning and commissioning was to pro-vide “advisory service” to the main contractor. This occurred for all process related activities in this project phase from mechanical completion up to the performance test run. The commissioning situation differs from previ-ous projects in two aspects:

Figure 2: FERTIL 2 ammonia plant. From left to right: reformer, ammonia synthesis, CO2 removal.

110 2014AMMONIA TECHNICAL MANUAL

1. In other projects, engineering, procurement, construction and commissioning (EPCC) is all done by TKIS. There, the commissioning team is familiar with the whole history of construction, and there is a natural seamless transition from construction to commission-ing without loss of information. At FERTIL 2 project, the commissioning team did not have the direct experience with the history of construction on site. Therefore, a system of proper transfer of information needed to be established in order not to run into the risk of coming on site without knowing about the particularities of the plant.

2. In other projects with one single EPCC con-tractor, this contractor can directly control the construction subcontractors as per the needs of the starting pre-commissioning. If this is not given due to different responsibili-ties, this can slow down the progress of the project.

From these aspects arises the strong need for proper information transfer between the main contractor and the technology provider. This had already been established during detail engi-neering by the system of so-called TANs (tech-nical advice notifications). In that project phase, TKIS assisted Samsung by having engineers from each discipline delegated to Samsung’s of-fices in Seoul, Korea, where the detail engineer-ing was prepared. TANs were prepared both as answers to Samsung’s questions as well as for potential problems observed by TKIS staff in 3D model reviews and other occasions. By a standard format, distribution and numbering, the TAN system makes sure each advice is properly reaching its destination and is available to the whole project team, not only to the involved in-dividuals. For an example refer to Figure 3.

Figure 3: Example for two TAN forms from detail engineering of FERTIL 2.


On plant site, main activities by TKIS were: Checking the plant against P&ID (part of the

check for mechanical completion (MC)) Checking the quality of plant assembly, like

supports and welding Monitoring the installations of equipment in-

ternals and packing Preparation of technology-related procedures

and coordination with Johnson Matthey for the preparation of catalyst related procedures, monitoring of the corresponding activities, and preparation of reports

Co-operation in checking programmed trip and interlock logics

Liaising with the licensors Stamicarbon and UFT for technology related activities in the urea plant

Preparation of detailed commissioning pro-cedures

Monitoring the start-up and test operation of the plant

The TAN system was continued and TANs were prepared for all issues and observations related to this scope. As a part of the responsibility for the safety of its own staff it is of course in the interest of the technology provider to witness or participate in the checks of the trip and interlock system. However, it should be noted that this is also in the interest of the whole project. A proper safety check takes time but it also helps not only to improve safety, but it also leads to a smooth and trouble-free start-up. In this project, thanks to TKIS’ participation in the trip and interlock check, deviations against design were discov-ered and corrected prior to start-up.

SORFERT Project

The Project

Another fertilizer complex recently commis-sioned is SORFERT in Arzew near Oran in Al-

geria, see Figures 1 and 4. SORFERT is a con-sortium of ORASCOM from Egypt and SONATRACH owned by the Algerian state. ThyssenKrupp Industrial Solutions (then Uhde) was responsible for engineering, procurement and commissioning. Construction responsibility was with OCIA, an Algerian affiliate of ORASCOM, assisted by TKIS advisors who al-so arranged the presence of the urea licensors’ staff and vendor specialists. The complex consists of: 2 x 2,200 t/d ammonia plant (Uhde process

with Johnson Matthey catalysts, BASF aMDEA CO2 removal)

3,450 t/d urea plant (Stamicarbon synthesis and UFT granulation)

all offsite and utility facilities, incl. sea water desalination, 2 x 49.3 MVA electric power generation (rated capacity), 15,000 t ammo-nia storage, 100,000 t urea storage and 400 t/h urea truck loading.

2 x 30,000 t ammonia storage and 1000 t/h shiploading in the port of Arzew, linked by a 9 km ammonia pipeline.

Figure 4: SORFERT ammonia / urea complex (ammonia plant reformer in the foreground). While the project size is very large, the process is fairly conventional and does not contain any particular risk or unproven equipment. An un-common element in the process is the upstream natural gas conditioning, consisting of:


Helium removal from feed gas: package unit, using UOP SEPAREXTM membrane technol-ogy. Helium must be removed from the feed gas because otherwise it would accumulate in the ammonia synthesis loop.

Mercury removal from feed gas: absorption by Puraspec 1163 by Johnson Matthey. Mer-cury must be removed from the feed gas be-cause otherwise it could collect in vessel sumps and embrittle their base metal, leading to catastrophic equipment failure.

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 prepara-tion of the mechanically erected plant for the start-up, that is cleaning by flushing and blow-ing, tests in cold condition, catalyst filling and similar activities. Organization and planning of pre-commissioning was part of OCIA’s construction responsibility. However, it turned out that sup-port by TKIS was required. This was given in the following form: More advisory staff by TKIS was sent to site to prepare pre-commissioning procedures for most subsystems. Like in all recent TKIS projects, the commercially available data base system ICAPS (Integrated Commissioning and Progress Sys-tem) was used to plan and to track the status and activities for each subsystem. This helped OCIA to organize the transition from purely mechani-cal construction to pre-commissioning.

When pre-commissioning was completed in a subsystem, it was handed over to TKIS who was responsible for the next step, commissioning and start-up. But similar to the FERTIL 2 pro-ject, the commissioning staff had to get familiar with the plant because construction and parts of pre-commissioning had been in the hands of an-other company. In order to avoid any safety risk, a so-called Pre-Start-up Safety Review (PSSR) was done using a certain formal procedure. Key elements are summarized in Table 1. One finding by the quality control was an unu-sually high hardness figure at the weld seams in the P91 material of the HP steam piping. This was caused by improper heat treatment during construction. It could have led to failure of the welds under high stress. All applicable welds had to be cut out and replaced. A bit unusual was the condition on site with fre-quent and unannounced strikes of the local con-struction personnel, several times blocking ac-cess to site. While in the construction phase this just meant progress delays, it was more critical during pre-commissioning and commissioning, when 24 hour operation of the utility units (wa-ter and boiler units) had already started. At that time, it sometimes happened that dayshift staff was prevented from accessing the site to relieve their colleagues after their 12 hour nightshift. Also unusual was the fact that the local authori-ties had established the rule that foreign staff had to travel from accommodation to site and back in convoy by police escort. For this reason, access to site was not possible at any time. This required good planning and discipline by all to meet the scheduled transfer times.


Uhde

Pre Start Up Safety Review (PSSR) System: Subsystems: P&IDs: Checklist Yes / No Remark 1 Pre-commissioning / Mechanical Completion … … 1.5 All instrument and control loops checked 1.6 All trip and ESD functions checked 2 HAZOP Comments Incorporated 2.1 Did any of the a.m. P&ID had comments related to the instrumentation

/ ESD system

2.2 If yes, have these been incorporated into the design 3. Design Changes (Instrumentation) 3.1 Is the P&ID Master Copy updated to as-built status … … 4 Area Visit 4.1 Scaffolding and barricades removed from the areas which need to be

accessible during commissioning

4.2 Area with commissioning activities is properly roped-off or marked

4.3 System is live marked 4.4 Field Safety Equipment like safety showers, eye wash stations, fire-

fighting equipment is operational

5 Information … …

Table 1: Pre Start-up Safety Review (PSSR) checklist, shortened to show the most critical items only.

Interruption of Start-up

Commissioning of the first train started in May 2012. Reliability test (30 days production at minimum 95 % capacity) of the first ammonia plant and the urea plant started in June. It was in full swing, and plans were made to start the per-formance test run soon when the import of liq-uid nitrogen, needed for utility nitrogen, was in-terrupted, caused by a problem in the supplying company’s facility nearby. The plant had to be shut down early July 2012. After liquid nitrogen was available again, restart was still not possible because the commercial operation permit was not made available by the authorities for reasons unknown to the authors. As it was first thought there was only a short de-

lay in issuing the permit resolved quickly, TKIS and other vendor staff remained on site for some time. Though, over the weeks, hope for a quick solution faded. However, also in this situation TKIS did not abandon the site. TKIS kept on supporting the client by developing a preservation concept for the complex and procedures to keep it in good shape.

Preservation and Conservation Measures

In July / August 2012 preservation procedures were prepared when it was thought the situation would last for about three months. Staff was re-duced. Always, one advisor each for urea, am-monia and offsites / utilities stayed on site. In the free time, training sessions were given for


the owner’s staff. Examples for preservation measures are put together in Table 2. Ammonia plant 2 had not yet reached mechani-cal completion, so construction continued. After some months, pre-commissioning started as usual because water, steam and air for flushing

and blowing were available. Finally, also cata-lyst was loaded. After the conditions did not improve, more rig-orous conservation measures were taken for train 1.

Utilities: Many utility units kept in operation: sea water, cooling water, instrument air and plant air supply. One of the three boilers was in operation. Electric power generation off and inertized. Ammonia plant 1: Process and fuel gas system filled with nitrogen. Water-containing systems (de-aerator and BFW pumps, turbine condensate and process condensate system, ammonia recovery unit) drained and filled with nitrogen. CO2 removal solution returned to tank, solution system filled with nitrogen. Steam headers in service; turbines and process boilers isolated from steam system. Machinery: Shafts turned every week. Operation of reformer fans, lube oil systems and seal gas sys-tems every week for 1 hour. Urea plant: The steam system of the urea plant kept alive. Oil systems started every week. Large pumps for ammonia and carbamate turned manually every week for a few turns. Ammonia system kept under nitrogen. HP synthesis drained and could be kept under air due to the good corrosion re-sistance of the Safurex material. Granulation: fans and granule handling equipment started regularly for short times. Safety: Where nitrogen is used, put warnings signs on the systems. Keep work permit procedure in place to ensure safe working procedures. Valves: To keep the plant clean, grease all valves and put covers around them. Valves operated all two weeks where possible. Electric motors: space heaters in operation to keep them dry. When machinery is started check for bearing temperatures and vibration.

Table 2: Examples for preservation measures at SORFERT. Ammonia plant 1 Urea plant Feed gas in first time 08.04.2012 CO2 available for urea plant; start of water run 09.05.2012 First ammonia (catalyst reduction completed) 19.05.2012 First urea 22.05.2012 Start reliability test 20.06.2012 Begin interruption 08.07.2012 08.07.2012 Restart after end of interruption 12.08.2013 17.08.2013 Continuation of reliability test 20.08.2013 20.08.2013 End of reliability test 07.10.2013 07.10.2013 End of performance test 12.10.2013 12.10.2013 Ammonia plant 2 Feed gas in first time: 15.07.2013 First ammonia 28.08.2013 Start reliability test 24.09.2013 End of performance test 10.11.2013

Table 3: Key dates from pre-commissioning and commissioning at SORFERT.


Second Start

After having been twelve months out of opera-tion, an operation permit was granted after long discussion between owner and authorities. Thanks to good preparation and preservation, the re-start went extremely smooth. No time was wasted and the ammonia plant reached full pro-duction 8 days after restart. The second ammonia train was then also started up quickly in six weeks’ time from feed in to first ammonia. Later, 106 % of nameplate capacity was achieved. More key data of the start-up are put together in Table 3.

Tools

Next to TANs and PSSR which have been de-scribed already, there are other simple 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 the Livening-up Notice. This is a notice declaring that a certain subsystem is going to be taken into operation. 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 plot plans, while commissioning thinks 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 countersigned by the construction management. It can be put up on the bulletin board in the site office containers for every-body’s information. 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 the 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.

Informal 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 in both of TKIS’ above mentioned projects, 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 Operating Manual. But it opens a path


for the commissioning staff to get feedback from the ordinary construction worker or op-erator (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-tion and startup activities. Thanks to their per-manent presence in all regions of 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

Some tools have been presented to improve safe-ty during (pre-)commissioning by mainly organi-zational measures by contractor and / or technol-ogy provider. Essential for safety is communication, which is improved by tools like TANs and Livening-up Notices. Better information about the plant con-dition does not only help to speed up commis-sioning, it is also a tool to ensure safety of the personnel on site. The fact that trip logic checks and PSSRs have detected incorrect conditions shows that they are needed. The tools should not only rest with the construction company, but it is the technology provider who should apply them because he knows where in (pre-)commissioning risks

could arise; he is the originator of the reference documents

such as trip and interlock descriptions.

This experience is highly relevant for the current projects of three urea plants and two ammonia plants in the USA where ThyssenKrupp Industri-al Solutions will provide advisory service for commissioning in 2015.


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