FLARE KNOCK OUT DRUMS (KODs)
NO ROOM FOR ERROR
HOW WE WORK
FLARE KNOCK OUT DRUMS (KODs)
NO ROOM FOR ERROR
In-country value is a key tenet of Petrofac’s philosophy and the drums package for Duqm is a perfect example – they were made in Oman by an Omani vendor.
The sheer size and scale of the KODs was a real test for the vendor and Petrofac’s Project Engineer and Engineer – Dharmendra Sharma and Rajendra Sharma, who are responsible for this particular package, together with the Samsung team who will install these drums in their flare area. (For scale, look at the size of the drum compared to the worker walking past below.)
The four KODs are part of the refinery’s flare system, which burns off leaked or unused gases from the refinery. “Such vessels are not built every day,” says Dharmendra. “In comparison pressure vessels are usually around 10 metres in length and 30 tonnes in weight – these drums are 24 metres in length and 154 tonnes each.”
After finalising the design in pressure vessel design software and the approval of documents, the team procures the raw materials needed and cuts the plates to the correct sizes, welding the pieces together. This is where the challenges begin.
Each KOD is around the same length of a tennis court – and the dimensions of each plate need to be precise so the drums are the right length. There is no room for error. “The parts are so heavy that you need to use cranes when you fit them together,” says Dharmendra. “It has to be in a few millimetres – we don’t have the luxury of centimetres.”
Another challenge is the welding of the ‘elbow’ at the top of the KOD – which Dharmendra says is one of the biggest and heaviest he’s seen in his 18-year career.
“We have to manage the tolerances of the elbow (see picture), as you are going to connect a pipe from here – the pressure is huge and the piping loads are also huge,” continues Rajendra. “When you are welding the elbow to the vessel, it is a difficult job to maintain it within the correct tolerances. Considering the huge piping loads, high thick insert plates are also provided to take care of the loads, which is a critical part of design.”
”Undignihil moluptae plabo atiunt lanis quidel iuscius ciisque.”
WORDS CHRISTINA McPHERSON
PUBLISHED AUGUST 2020
Dharmendra Sharma
We explore the different components and parts that make up the package.
Click on the crosses for more information.
Nozzle
All the combined mixtures which come from the various processes within the refinery to be flared will enter from this nozzle. Any liquids will drop out and settle at the bottom of the vessel based on density. Only the gases pass through and move towards the 180 m high flare stack. If liquid travels to a flare, it would burn in the open air and be very hazardous. The KODs prevent this from happening (burning rain).
Saddle supports
Steel supports for horizontal vessels.
Anatomy of a drum
Lifting trunion
Attachment provided to lift the equipment for movement, transportation, and erection of the equipment.
Vacuum stiffener rings
Rings are made of flat bars or plates, or structural shapes welded around the vessel. These rings are installed on vessels operating under external pressure to prevent the collapse of the vessel.
Elbow
It is one of the most challenging parts to weld. There is a danger of it buckling or going out of shape. A pipe is also connected here which will add more weight. The team had numerous discussions with the vendor to decide on the type of support and the thickness of the reinforcement.
Size and scale
The drums are fabricated from a boiler grade steel and are around 5.3 m in diameter, 24 m in length. Thickness of the plates is around 25 mm and the total weight is 154 tonnes.
What are they?
Pressure vessels simply hold a pressurised contained fluid and can adhere to different design codes based on their pressure limits. There are more than 50 pressure vessels across the utilities and offsites in total. The drums are designed in adherence to the ASME code.
Nozzle supports
Plates welded to the nozzle for strengthening purposes.
The KODs undergo various testing including a hydrotest which checks the integrity of the equipment and that it can withstand the desired pressure during operating conditions. Then, the KODs are heat treated to remove any residual stresses from the welding process.
The KODs are so big that the vendor had to construct a bespoke furnace for the post-heat treatment. “It has to be done in a single part as some portions can’t be heated more or less,” continues Dharmendra, “so the vendor manufactured a huge furnace so it can be burned out evenly.”
Dharmendra regularly visits the vendor and has seen the KODs at each stage – from the drawings to the raw materials in the vendor’s shop to the finished product. So, what’s it like seeing them come alive?
“It is really a very unique and interesting experience seeing the drawings on paper being transformed into something physical,” says Dharmendra. “I have to keep an eye on everything – from engineering to quality to safety. There are so many stages and you are praying that nothing should go wrong.”
“We always have to be on our toes – we have to be very cost effective but at the same time we have to keep it safe and of high quality,” adds Rajendra. “I consider myself responsible for my packages and provide optimised design to the other disciplines and the vendor. We are accepting the challenges and finding positive ways to perform tasks. Any mistake may lead to disaster at a later and have major repercussions. It’s a very challenging role.”
Rajendra Sharma
In pictures
The size and scale of the drums presented many challenges for our engineering team
Explore some of the other packages
