safe pre-commissioning and commissioning of a multi

Safe Pre-commissioning and Commissioning of a Multi-Product Syngas and Ammonia Facility

This paper will discuss the various technical and safety challenges associated with pre-commissioning and commissioning of a new multi-product syngas facility. It also focuses on the subtle nature of

developing an effective site safety culture to enable safely working in excess of 10,000,000 man-hours with a multinational workforce in the Middle East.

Omer Hashmi Selas Linde North America

Nrup Patel Linde Engineering India

Fernando Rivera Linde Jubail Industrial Gases Factory LLC

Introduction he Linde Group’s Engineering Division has engineered, delivered and construct-ed a new state-of-the-art multi-product syngas and ammonia facility at the new

SADARA Chemical Company complex in Al Jubail, Kingdom of Saudi Arabia (KSA). Upon successful commissioning and start-up, Linde Group’s Gases Division will own and operate the plant to supply hydrogen, carbon monoxide and ammonia to SADARA. The syngas ammonia facility is comprised of a dual-train Syngas Generation section feeding a single train of ammonia production. Additional-ly, a refrigerated atmospheric ammonia storage tank of 20,000 ton capacity is included to

ensure a continuous supply of product to the cli-ent during any scheduled or unscheduled down-time. Other process units enable recovery and purification of additional gas products, such as high-purity carbon monoxide (CO). A multinational team of commissioning engi-neers from various Linde Engineering (LE) of-fices combined on this project to execute safe and efficient pre-commissioning, commission-ing and start-up of this facility.

Process Description A dual-train concept was chosen for syngas generation in this facility. The two trains are physically identical; however, one train gener-ates clean export steam according to customer's

T

2212016 AMMONIA TECHNICAL MANUAL2192016 AMMONIA TECHNICAL MANUAL

specification, whereas the other train generates process steam for internal use only. The steam system of the latter recycles the process conden-sates of both trains to reduce effluent flows for environmental reasons as well as economic effi-ciency. Natural gas from battery limit is compressed and distributed to the reforming section of the two syngas trains. Downstream of the reform-ers, the hot syngas is cooled down by a series of heat exchangers before being fed to the carbon dioxide (CO2) removal amine wash process. The separated CO2 is compressed and recycled back to the process as feed to the reformer on an as-need basis. A Temperature Swing Adsorption (TSA) unit then removes all moisture and any residual CO2 from the syngas, in preparation for the cryogen-

ic separation and purification of CO within the coldbox. The purified CO is compressed and sent to battery limit as one of the products, and the remaining process gas is directed to a Pres-sure Swing Adsorption (PSA) unit to produce pure hydrogen (H2). The product H2 is then mixed and compressed with high pressure nitrogen (N2) from battery limit and fed to a Casale ammonia converter. The converted gas is passed through heat ex-changers for energy efficiency before being condensed and refrigerated for storage as liquid ammonia product. The product ammonia is then vaporized before it is finally distributed to bat-tery limit. Figure 1 summarizes the described process in a block flow diagram.

Figure 1. Block Flow Diagram of the HyCO Ammonia Plant

222 2016AMMONIA TECHNICAL MANUAL 220 2016AMMONIA TECHNICAL MANUAL

Planning and Workflow During the course of an engineering, procure-ment, construction (EPC) project, Linde Engi-neering divides a plant into separate “hand-over-systems” (HOS) based on Linde's vast experi-ence in pre-commissioning and commissioning of chemical and petrochemical plants. Each HOS is handed over from construction to pre-commissioning as soon as a system is “ready for pre-commissioning”. Similarly, upon comple-tion of the planned pre-commissioning activi-ties, a system is declared “ready for commis-sioning”. For the Al Jubail syngas ammonia facility, the plant was split into nearly seventy (70) different HOSs. The size and complexity of these indi-vidual systems varied greatly ranging from a small system within the syngas cooling chain to the large intricate coldbox. Each hand-over-system had its own procedure for executing the required pre-commissioning activities. However, some activities such as checking the construction against the P&ID, in-ertisation of piping and equipment, and carrying out tightness tests were common for all HOSs. Right from the onset of construction on this pro-ject, no activities were executed without a prop-er permit to work. One of the key factors in the safety success of Linde here is the thoroughly implemented “permit to work” system. The dif-ferent pre-commissioning and commissioning activities required different permits, which in-cluded, but were not limited to, a General Work Permit, a Hot Work Permit, a Confined Space Entry Permit and a Working at Height Permit. Each one of these individual permits requires its own series of steps to be followed in order to plan, supervise and execute the task safely. As an example, Figure 2 shows the general work-flow of how a task requiring a confined space entry permit is managed.

Figure 2. Workflow for Confined Space Entry

Work Permit The confined space is first recognized as an en-closed area and the hazards are assessed. A risk assessment is then performed to identify haz-ards, analyze and evaluate the risks, identify control measures and assess the method of work. Some critical considerations during this assessment include, but are not limited to, iso-lating energy sources, sufficient Lockout/Tagout (LOTO), purging of systems and equipment, lighting requirements, atmospheric testing for oxygen content, ventilating with air blowers, providing a means for access and/or any addi-tional personal protection equipment (PPE). A clear definition of “how” the work will be performed is also a part of this permit issuing process. Items such as number of workers re-quired inside the confined space, personal gas monitoring requirements, tools and equipment to be used, emergency control and arrangements etc. are all valuable parts of preparing such a permit. Prior to the activity, the roles and re-sponsibilities of each concerned individual were clearly explained to allow the task to proceed as smooth as possible. Upon completion of the permitted task, the system is returned back to its “normal” operating state.


A noteworthy item in the permit to work system for this project was the emphasis on adequate training and timely refresher courses on safe ex-ecution of critical tasks such as confined space entry. The Linde team, along with the construc-tion workforce, was able to establish a number or interconnected codependent teams training, intelligently challenging, discussing and work-ing together to achieve excellence in safety by taking ownership and responsibility for them-selves as well as for others. Based on the size, complexity and criticality of the HOS, and the nature of activities, the com-missioning management team assigned man-power and developed a time schedule. Addi-tionally, great importance was placed on vendor packaged units such as compressors and pumps to ensure similar activities were also executed for those units with an equal emphasis on safety.

Establishing a Safety Culture One of the key success factors in this story was the establishment at site of a positive safety cul-ture. Rather than seeking to “catch and punish” personnel who might be performing an unsafe act, Linde sought to switch the mindset of every person on site from the traditional reactive / pu-nitive / independent mode, to a pro-active, sup-portive, and inter-dependent mode. This is ac-complished when team members not only look after their own safety performance, but the safe actions of others as well. This kind of a safety culture has been best de-scribed by “The DuPont Bradley Curve”, shown in Figure 3, which was designed in 1995 to benchmark the path to a world-class safety per-formance.

Figure 3. The DuPont Bradley Curve

(Image copyright © 2016 DuPont. All rights reserved) In this project, the stakeholders, the project management team, the execution team, the con-struction and the site team, all the contractors as well as the client, all worked together towards achieving the unified goal of a world-class safe-ty performance. The project as a whole has been able to achieve in excess of 10,000,000 man-hours without a Lost Time Incident (LTI), and counting. An example that depicts the camaraderie of the teams in this project to achieve such a milestone was the transfer of the site safety responsibility from the Engineering Division to the Gases Di-vision after Mechanical Completion (MC) of the project. Despite the transfer of responsibility being achieved only after MC, both Linde Gas and Linde Engineering have worked together from the beginning of this project as one team not accepting low standards of safety or risk tak-ing. The two entities truly believed and strived for long term sustainable improvement to achieve the target of zero injuries.

Pre-commissioning Given the large size and the diverse nature of the various sections of this plant, pre-commissioning posed not only technical chal-lenges, but also scheduling concerns.


Additionally, due to delays in the supply of some major utilities, the safe execution of scheduled tasks required added planning and watchful efforts. One such effort was the organ-ization of compressed air supply by means of a temporary air compressor and a dryer station. Such temporary sources, while very helpful, al-so meant increased operational and safety con-cerns during the various pre-commissioning ac-tivities of the plant. Each pre-commissioning activity brought about its own unique safety challenge thereby requiring the entire team to constantly improvise and work together to maintain the site safety culture.

Initial Check of HOS against the P&ID

Once a system was deemed “ready for pre-commissioning”, a commissioning engineer checked the system for consistency of construc-tion against the P&ID. While this activity sounds fairly straightforward, one of the biggest safety challenges was dealing with the scaffold-ing that covered most of the plant at the time, especially the pipe rack, as seen in Figure 4.

Figure 4. Scaffolding around main pipe rack

Site rules required 100% tie-off using a safety harness when on a temporary structure. In fact, for even permanent structures such as platforms and vessels, until the safety department had thoroughly inspected the integrity of the struc-ture itself, a safety harness was mandatory for all personnel. This was followed strictly both by Linde personnel as well as the construction contractor’s workforce, as seen in Figure 5.

Figure 5. 100% tie off on elevated structures

Cleaning of Equipment and Piping

Cleaning of equipment and piping is one of the most critical activities in pre-commissioning of any plant. In the case of this facility, the dusty weather and surrounding desert meant that extra attention had to be paid to cleaning of lines. After a preliminary check confirmed that tie-ins were as per the P&ID, and that correct valves and piping components had been installed, the lines and equipment were cleaned by air blow-ing, Figure 6, water flushing or sand blasting.

Figure 6. Air blowing of lines

Safe execution of cleaning requires a lot of planning and preparation. The blow-out points were temporarily barricaded and a horn was sounded to ensure that those in the vicinity were not caught off-guard or without any form of ear


protection. In general, the team managing and supervising such line blowing activates utilized ear plugs and/or ear muffs rated between 95 and 105 decibels, as in Figure 7a. In the case of steam blowing, to minimize the noise generated, the steam was blown into the atmosphere via a silencer, as shown in Figure 7b.

Figure 7a. Use of ear muffs for protection

Figure 7b. Steam Blowing via Steam Silencer

Inspection of Equipment

Most large sized equipment needs to also be cleaned and inspected to minimize complica-tions during commissioning and start-up. Reac-tors, separator vessels, drums and furnaces need to all be checked thoroughly. The challenge with this kind of equipment is that these are all

confined spaces and they must be dealt with ex-treme caution. As part of the pro-active interdependent ap-proach for maintaining a world class safety cul-ture in the facility, as an absolute minimum, each individual entering any confined space was required to carry a personal gas detector with alarms to ensure continuous gas monitoring, a ventilation source was made available to ensure sufficient oxygen content, a watchman was available outside the confined space maintaining an entry/exit log sheet, and an adequate lighting source was organized as well. One of the key success elements of this project was the training and ownership of designated watchmen for confined space work. Their du-ties, which they were duly trained in, included an awareness of activities inside the confined space, verbal communication with authorized entrants to ensure their well-being, maintaining an entry-exit log, remaining vigilantly placed outside the confined space during entry opera-tions, including when entrants leave for breaks unless all openings are properly secured to pre-vent unauthorized access. These watchmen were a great example of the interdependent safety culture that the Linde Group achieved in this project. Most of their responsibilities focused on the safety of other personnel involved in the task but their responsible ownership of safety was a highlight of this project. In certain special cases of confined space activi-ties, additional safety efforts were required. In the case of the reformer refractory inspection for example, the danger is compounded because not only are the people working in a confined space, but also working at height. Even though it may not have been very comfortable at the time of these inspections, all personnel maintained a safety harness during this inspection inside the reformer furnace, as shown in Figure 8.


Figure 8. Use of safety harness inside furnace

Filling of Catalyst and Adsorbent Materials

In parallel to systems that were still under con-struction or under cleaning, hand-over-systems whereby catalyst and adsorbent loading was re-quired were also catered. These activities posed a completely different safety challenge – dealing with hazardous chemicals. In order to minimize exposure to catalyst dust, all workers assigned to the catalyst handling and loading jobs, were specifically required to wear a dust mask in addition to the regular personal protection equipment (PPE), shown in Figure 9. To improve on efficiency and avoid duplication of efforts; the same crew of workers was main-tained for catalyst loading activities wherever possible.

Figure 9. Dust masks during catalyst loading

Additionally, catalyst and adsorbent loading meant lifting of heavy drums to elevated struc-tures. In addition to safety coordination and skillful lifting, as shown in Figure 10, this re-quired organization of working areas, providing the workers with sufficient space to execute the task properly, as well as barricading areas at grade, directly under the lifting radius to prevent people from working directly under a lifting ac-tivity.

Figure 10. Lifting of empty catalyst drums


Final Check of HOS against the P&ID

Following the line and equipment cleaning, the HOS was reassembled and a more thorough check was done to ensure that the system was ready for pressurizing and testing for tightness. During this check, subtle details of the piping are verified to ensure that the system is ready to be pressurized. This was one of the greatest strengths of the commissioning team on site. When dealing with a facility of this magnitude, it is not uncommon that some items are missed during construction due to time constraints and emphasis on getting the job done. However, sufficient time and effort was scheduled for the final checks of each HOS. Some of the interest-ing findings included loose flanges, leftover temporary construction blinds, damaged gas-kets, missing insulation etc, shown in Figures 11a. and 11b. Finding these items upfront meant that the HOS was handed back to the construction department for further reinstatement. This minimized future issues whereby the system may have already been pressurized.

Figure 11a. Loose flange on PSV inlet

Figure 11b. Damaged gasket

Testing of the Control and Trip System

Another parallel and very critical item during pre-commissioning was plant-wide safety func-tion testing. Prior to charging process gas into the system, the control philosophy and the trip system were verified at length. For the testing of Safety Instrumented Functions (SIFs), a HART communicator was used to simulate inputs from the transmitters in the field. In the case of pressure transmitters and differential pressure type flow transmitters, a pressure calibrator was additionally used to veri-fy the working of the transmitter. The testing of each SIF was carried out based on individual SIF Protocols prepared by the engineering team. These tests comprised of manually testing the final element first, followed by the testing of the transmitter and lastly the testing of the control logic implementation and verification of final element action.


One distinct Safety Instrumented System (SIS) was the flame detection system for the reformer burners. With fuel gas not available on site, this was done using a portable gas cylinder. A de-tailed Job Safety Analysis (JSA) was performed in preparation of the activity. Based on this, a flint lighter was to ignite a flame, Figure 12a, in the presence of a fire extinguisher and only 100% fire retardant clothing was permitted for this activity, Figure 12b.

Figure 12a. Flint lighter for ignition

Figure 12b. Flame scanner testing

Once again, the motivation of the workforce and entire site team was that of achieving unparal-leled safety success. If that meant taking some time, planning and only then executing a task, this was never compromised on.

Tightness Tests

Once the final reinstatement of a HOS was completed, the system was pressurized with low

pressure compressed air, in most cases to nearly 20-30% of normal operating pressure, and the pressure drop of the system was monitored over time, to determine if the system was “tight” i.e. holding pressure. During pre-commissioning, this was considered one of the more monotonous tasks – pressuriz-ing each HOS with low pressure compressed air and searching for leakages in the system by us-ing a soap solution bubble test, as shown in Fig-ure 13.

Figure 13. Soap Solution bubbles forming at

gas leakages However, in retrospect, this proved to be one of the most valuable investments of time and re-sources; especially after high pressure nitrogen was received later on and the systems were test-ed for leakages at higher pressures. The systems in the dual syngas generation trains were leak tested at normal operating pressure with high pressure nitrogen. However, due to the high op-erating pressure of the ammonia generation loop, these systems were only leak tested to about 20% of the normal operating pressure. Once again, this was a prudent collaboration of several teams working together – first team working to find these leaks, then recording and maintaining tracking lists of these leaks, and lastly the team rectifying these leaks well in ad-vance of actual pressurization with combustible, toxic process gases.


Vendor Packaged Units

For any plant, a particular area of concern, both technically as well as from a safety standpoint, is the tie-in of vendor packaged units to the bal-ance of the plant. This plant had several vendor packaged units of this nature, ranging from sim-ple centrifugal pumps and reciprocating com-pressors to the more complex refrigeration screw compressors. Each of these packaged units was treated as its own hand-over-system. This meant that it was individually checked for construction against the P&ID, the lines were cleaned, and the con-trol logic was verified. An important item of safely testing such units was the electrical isola-tion of the motor in the Motor Control Center (MCC) and temporary wrapping of the wiring with insulation tape, as shown in Figure 14.

Figure 14. Electrical isolation of power supply

This isolation was required to allow testing the trip logic of the different compressors without having to actually run the machine. This al-lowed safe testing of the packaged units without risking the safety of the machines.

Commissioning Commissioning and start-up of any plant in-volves take-over of utilities and start of nitrogen circulation within the process units. Prior to in-troduction of any flammable gases, the flare unit needs to be ready for commissioning and start-up. This facility comprised of two individual flares – one for the dual syngas generation trains and a separate one for the ammonia production sec-tion. However, in preparation of charging the fuel gas header, the safety process and require-ments were revisited. Several new requirements were mandated in addition to the existing rules and regulations, such as: • 100% Flame Retardant Clothing (FRC) • Personal gas detectors • Usage of only non-sparking tools

The facility is currently in the middle of its commissioning and the experience during this phase is still being gathered. Safety of the pro-cess, plant and personnel continues to remain a top priority during these ongoing activities.

Flare Systems

The commissioning of the flares presented a new technical and safety challenge. A few pilots on the flare dedicated to the syngas section of the facility did not ignite upon introduction of pilot fuel gas. Since safely accessing and re-pairing these pilots from the platform was con-sidered risky, despite the necessity to meet a va-riety of commissioning schedules, a scaffold had to be erected on top of the flare, approxi-mately 60 meters (200 feet) tall, to inspect and troubleshoot the pilots, shown in Figure 15.


Figure 15. Scaffold for flare troubleshooting

Once again, a detailed JSA was performed and special emphasis was placed on the climatic conditions of Al Jubail, due to extreme windy conditions. Even at acceptable wind speeds, work on the flare was sometimes suspended to ensure that the safety of personnel and plant was not compromised.

Syngas Section

Following the modification of the syngas flare, the feed gas introduction to the plant was possi-ble and the first reformer was fired up. Positive isolation was implemented by closing perma-nent blinds on the second syngas train to prevent unplanned pressurization. Despite leak tests that were performed during pre-commissioning, some small leakages were detected via portable individual gas detectors on the fuel piping of individual burners. Additionally, the amine wash process for re-moval of CO2 posed a totally different chal-lenge. A chemical suit was to be worn for the dilution and loading of the solvent into a storage tank. The combination of young commissioning engi-neers and senior engineers provided a very pro-active approach to the commissioning of the

syngas train. The CO2 compressor was initially left isolated to minimize the potential of carry-ing over dilute amine into the compressor in case the regenerator column had foaming and/or a sharp level increase. While doing so, the op-erations team was advised to monitor the CO2 vent silencer closely. The CO Compressor housing had CO leakages in spite of thorough leak checks and successful tightness tests. Fixing these leakages was new safety challenge given the toxic nature of CO, a.k.a. “silent killer”. The compressor shelter was left open to dilute the atmosphere inside and the exhaust fans were switched ON. Addi-tionally, an instrument air hose was used to con-tinuously purge the area of activity and the flange being worked on. The number of person-nel inside the compressor housing was mini-mized for the duration of this activity and each individual was carrying a personal CO detector with alarms. One unit at a time, process gas was introduced to different sections within the syngas train. Slowly, several online analyzers were also commissioned and on spec production of H2 and CO was confirmed.

Ammonia Section

Due to slight schedule delays, the commission-ing activities of the ammonia section have not yet commenced. The planned activities include, but are not limited to, replacement purge of the nitrogen atmosphere with ammonia, commis-sioning of the compressor packages, Casale convertor, refrigeration unit and the ammonia tank.

Conclusions Linde Engineering has engineered, delivered and constructed a new multi-product syngas and ammonia facility at the new SADARA Chemi-cal Company in Al Jubail, KSA. Throughout the pre-commissioning and commissioning ac-tivities so far, safety has been a top priority for


the entire team. By paying attention to delicate details, the entire project team successfully es-tablished a culture of interdependent safety at the site. The entire workforce, comprising of Linde En-gineering Division, Linde Gases Division and the construction contractor, has worked together as one team with a common goal of achieving excellence in safety by taking ownership and re-sponsibility for themselves as well as for others. Adhering to all safety regulations, the site team has successfully achieved in excess of 10,000,000 man-hours without a Lost Time In-cident. The world class safety culture achieved by the team in this project can be attributed to a num-ber of key success factors, such as:

• Valuable investment of time and re-sources in pre-commissioning during tightness tests and P&ID checks to min-imize downstream complications

• Distribution of roles and responsibilities between the entire team resulting in ownership and an interdependent work-ing relationship

• Functional implementation of a detail oriented permit to work system

• Comprehensive training of the work-force and efficient specialization of their working skills (like watchmen for con-fined space entry works)

• Planning, discussing, supporting and challenging each task to ensure that the safest practices are followed

Throughout the project, the entire team has truly believed and strived for long term sustainable safety practices to achieve the target of zero in-juries. As milestones have been achieved, the entire team continues to work towards the exe-cution of commissioning activities with the same diligence, and is committed to achieving the next safety landmark.

Acknowledgements

The authors gratefully acknowledge the contri-butions of the following individuals and organi-zations, without whom this paper would not have been possible:

• Linde Jubail Industrial Gases Factory • Selas Linde North America • Linde AG Engineering Division • Linde Engineering India • Kenneth Lamb • Jamil Amir Baduwi • Winfried Leclaire • Bernd Klein • Nirav Gabani • Florian Darchinger


safe pre-commissioning and commissioning of a multi

Documents