Retrofit

Due to its low weight, and small foot print coupled to its modular design the CiBAS WHRU is ideal for retrofitting onto existing Platforms or FPSOs to replace a Traditional WHRU or to where a gas turbine is available to increase the facilities process heat supply

Case Study

The client when planning to tie back a number of additional fields that it had discovered and developed to an already operating offshore processing facility. The Client had calculated that the additional product flow through the processing plant would exceed the current process heat rising capability.

However on the facility there was a gas turbine driven compressor set that was at that time running in open cycle mode which could be utilised to recover heat from providing that a WHRU could be installed into the space that was taken up by the silencer, stack and support steel-work.

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Photo 1: The Installed CiBAS Unit alongside the Traditional Units

Having taken the process data and the projects requirements from the client CiTECH calculated that there was sufficient space for a CiBAS Unit to be installed and only minimal reinforcing work to the existing structure was required to support the unit.The early calculations also showed that the dry weight of the unit would be in the region of 50 tonnes. As a single lift this was outside of the facilities crane capabilities of 15 tonnes at that reach, therefore the Client would be looking at hiring a heavy lift crane if the unit was to be installed as a single lift. The cost of hiring a crane with this capability was high coupled with the unpredictable weather conditions that frequented the area made planning the lift difficult and as a result cost were predicted to rise.

 

As a result the client asked CiTECH to review their design and provide an option to enable the use of the facilities crane albeit with its limited lift capability.

Although the CiBAS is a modular design CiTECH had to go back to the design drawing board and produced a design that broke down the unit into a series of units that could be lifted into place and assembled in situ.

To ensure that all the parts fitted together two dry assembly tests were carried out in the factory yard before the unit was shipped out in its component parts.

The most noticeable change was to split the helical coil heat exchanger into two pieces, with each piece being secured into its casing section.

The following series of pictures shows the assembly of the unit onboard the facility

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1. Lower Casing being lifted into postion

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2. Lower Casing Installed

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3. Lower Coil & Casing being lifted into postion

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4. Upper Coil & Casing being lifted into position

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5. Plug being installed

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6. Plug Sleeve & Upper Coil

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7. Top Cone & Stack Installed

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8. Unit Installed complete with Access Ladders & Platform