Planning of Commissioning Activities for Ammonia Plants

Planning of Commissioning Activities for Ammonia Plants

The key in the planning of commissioning is the definition of functional systems. Functional systems are sections of the plant, which are put in service as one process system.

Commissioning packages must be defined according to this systemic approach. In case such a detailed planning of activities has never been carried out before in a specific plant, enough resources must be foreseen for the execution of this comprehensive task.

A concise stage 1 plan gives an overall guide to the commission activities to be undertake

A detailed stage 2 commissioning schedule will provide a very accurate duration for all commissioning activities to be performed

The development of a concise and accurate commissioning schedule of activities is very important not only to the overall loading of the project schedule, but the plan also becomes an excellent guide for the commissioning team in the correct prioritization and execution of the various steps that make up the whole commissioning effort.

This level of commissioning schedule must represent the generic range of commissioning activities that the team will perform throughout the project and the time it will take to complete each action

Scheduled activities and timings that must be considered for inclusion within the Phase 1 commissioning scope are:

Agree commissioning scope

Support design at: Hazard Study, P&ID reviews, Layout reviews, 3-D Model reviews

Compile commissioning resource plan

Determine handover philosophy

Determine plant acceptance criteria

Confirm product validation criteria

Compile initial commissioning philosophy

Systemize the plant

Compilation of the commissioning manual

Period for selection and appointment of the commissioning team

Develop detailed commissioning plan

Training period for the commissioning team

Agree operating procedure production requirements by commissioning team

Compile commissioning documentation

Compile training manuals

Compile Operating Procedures

The objective of this level of commissioning schedule will be to accurately determine each individual activity the team will perform and its duration.

As the stage 2 commissioning schedule concentrates on actual delivery of the commissioning activities, it is very detailed in composition.

The stage 2 plan will commence after the mechanical completion milestone date per system. Therefore, this level of detailed commissioning schedule cannot be logically completed (activities can be populated to the schedule), until the construction group has been given a breakdown of commissioning systems and therefore planned their mechanical completion dates according to all the factors which the construction team will need to consider; examples will include delivery of equipment, erecting of steelwork and major pipework systems.

A list of example system activities that must be considered for inclusion in a Stage 2 commissioning schedule are:

Attendance at factory acceptance tests and inspections

Train plant and maintenance operatives

Check construction progress

Test and clean pipe and equipment – per system

“Dry” functional tests (e.g. loop tests, rotating direction tests, cold alignments)

Refractory dry out work requires a specific dry out process to avoid cracks because of evaporating water.

Leak tests (e.g. tubes of heat exchangers) to locate repair scope

Leak tests of manholes prior to catalyst filling or for low pressure systems

Special attention to flange surfaces

Special attention to the gasket(s)

Special attention to the tightening procedure

Blowing, post-work cleaning, packing and internal installation

Catalyst loading

Reduction of catalyst: Most of the catalysts in ammonia plants are delivered in the oxidized form and must be reduced by application of hydrogen. In most cases this commissioning step takes place after most parts of the plant have been commissioned and plant is in startup operation.

Lubricants, oils, cooling media etc. in test plant utilities

Electrical energization and utilities introduction sequentially

Receive discipline approvals

Punchlist – per system

Loop testing – per devise, per system

Motor rotation checks – per item within a system.

Turbine and compressors checks. In many cases commissioning of turbines and compressors requires the availability of high and medium pressure steam. Therefore, these commissioning activities, machine control and interlock tests are performed also during the start-up of the plant.

Leak testing – per system

Drying of functional systems (Check for the quality of drying can be performed by measurement of dew point (recommendation below -20 °C).

Purging of functional systems

Sequence check-out without chemicals

Commissioning on safe chemicals, water commissioning – per system

Utility system start – up

Instrument air system

Cooling water

Nitrogen grid

Steam for heat purposes

Loop tuning within a system

Testing of control sequence s, interlocks and shut-down systems on safe chemicals

Heat tracings and heaters are taken into service.

Burners check: during the commissioning of the burners, control interlock sequences as well as performance parameters, like flame shape and colour are checked.

Lubrication units (joint check plant operator with vendor)

Complete all PSSR paperwork and/ or Hazard Studies 4 and 5 – per system

Issue first draft SOPs

Start-up procedures

Validation period

Acceptance period

Ramp up of production to design rate period

On the job training of operations

Handover to operations

Consolidation period, updating of documentation with best operational

Housekeeping adequate for start-up

Floor and tripping hazards

Scaffolding sufficiently removed / in place for start-up

Delayed jobs under control (working permits, fenced off without interfering with start-up activities, no works during critical stages)

Adequate lighting

General access to buildings and escape routes clearly identified

Access for operations and maintenance

Guarding of machinery

Safety devices in operation (emergency stop devices, emergency showers, sprinklers)

Insulation enough to avoid blockages in the process and critical exposure of people

Sealed surfaces and pits cleaned / emptied to avoid contamination or blockage of sewer systems

Position and tightness of drain valves checked

Safety relieve systems like blow down systems or weep hole systems checked, burst discs in place; all transportation securities are removed

Blinds removed from plant in a controlled and systematic way

Orifice plates correctly mounted

Lock, chains, seals and tags removed from valves

Temporary gauges, valves, fittings and similar dismantled

Caps, plugs and temperature element pockets are correctly fitted and equipped with thread tape

Provisional utility connections and nitrogen hoses removed

Connections to blind flanges removed

Caps mounted

Check interlock override list and shut down panel overrides according start-up procedures

Bypass valves closed. In case of an open bypass valve with “shut off” function the interlock is in “override” mode

Labeling of valves, instruments, lines

All modifications checked against Engineering Lead Documents (e.g. P&IDs, Isometrics)

References:

Killcross, M.: “Chemical and Process Plant Commissioning Handbook” (2012)

De – & Recommissioning Guidelines for Ammonia Plants, Hans Juergen Essl, Leonhard Werner, Borealis Group Austria

Safe Pre-commissioning and Commissioning of a Multi-Product Syngas and Ammonia Facility, Omer Hashmi Selas Linde North America, Nrup Patel Linde Engineering India,

Fernando Rivera Linde Jubail Industrial Gases Factory LLC

Health Safety Executive UK, “HSG 253 – The safe isolation of plant and equipment” (2002)