Exhaust gases from the platforms emergency generators were suspected to be entering the main heating, ventilation and air conditioning (HVAC) air intakes through air handling units (AHUs), leading to reports of a diesel exhaust smell inside the modules and uncomfortable living conditions. Our client obviously wanted to identify and fix this issue as soon as possible so a quick turnaround was required.
Through modelling, it was found that for certain combinations of exhausts, wind speeds and wind directions, the exhaust fumes were blown into the HVAC inlets. Potential solutions were then discussed with the client and ranked, based on their cost and feasibility. The top solutions were then simulated to determine their effectiveness. Following this, a firm recommendation was made to eliminate the problem, where a novel dual-routing exhaust was proposed. This solution was subsequently designed by Apollo and successfully installed by our brownfield modifications sister company, Global E&C.
When the platform emergency generators were running, there were reports of a diesel exhaust smell coming from the module vents. Although toxic levels of exhaust had not been detected, this exhaust smell was linked to headaches and uncomfortable living conditions in the platform accommodation.
A range of wind conditions were modelled, and it was confirmed that the exhaust gases could enter the HVAC inlet for certain combinations of windspeed and wind direction. In certain wind conditions, the exhaust plume was blown into the platform modules and engulfed the HVAC inlets. These results tied up well with the observations from the client.
And for all you engineers who want more details:
A range of steady-state conditions were considered, where changes in the wind speed and wind direction were assessed. An atmospheric velocity profile suitable for the platform’s location was imposed at the model boundary. The modelling results confirmed the client’s reports of the HVAC contamination and clearly showed that for certain wind conditions exhaust gases were entering the HVAC inlets. This confirmed the source of the contamination and allowed potential solutions to be tested.
What did the client think?
A total of 9 solutions were prepared by Apollo and presented to the client, and the best way forward was agreed based on their pros and cons. A dual routing of the exhaust piping was decided on, allowing the client to choose the exhaust gas route depending on the weather condition. This dual routing solution was designed by Apollo and installed offshore by Global E&C. As part of the design process, a laser scan of the area was performed and the proposed exhaust piping marked up on the scan results, shown below. This enabled any clashes with existing structures and equipment to be negated and allowed the client to readily see the proposed piping.
The client, whom we have worked with closely over the past 5 years was very pleased with the execution of the project and the end result combining our analytical skills with offshore execution.
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