Atmospheric Condenser For A New FPSO Boiler Installation
As part of the FEED works for a new FPSO planned for deployment in the Southeast Asia region, one of the key conversion items is the installation of a new 100 T/h boiler. In this project, most of the generated steam will be used for topside heating applications, which makes condensate handling and steam discharge management an important part of the overall system design. Under these conditions, a new atmospheric condenser to be installed in the engine room becomes a necessary supporting package, not only for process performance, but also for safe and stable vessel operation.
In offshore projects such as FPSO conversions, equipment selection is rarely only about meeting a duty on paper. Space limitations, marine operating conditions, maintainability, corrosion resistance, and integration with the existing engine room arrangement all have to be considered from the early design stage. That is why the atmospheric condenser should be evaluated carefully during FEED, especially when it is connected to a large steam system associated with a new boiler installation.
For this project, the atmospheric condenser is expected to handle exhaust steam on the shell side at approximately 90,000 kg/h. The steam will be condensed and cooled to an outlet temperature of 65°C. On the tube side, the cooling medium flowrate is currently considered at 1,180 m³/h, subject to final vendor confirmation, with an operating pressure of 2.0 barg. The cooling medium enters at 27°C and is expected to leave the condenser at below 40°C. These conditions indicate a substantial heat rejection duty and require a condenser design that can operate reliably in continuous marine service.
An atmospheric condenser in this kind of application is used to condense low-pressure or exhaust steam when recovery to a closed vacuum condensing system is not required. In a boiler-driven topside heating system, it serves as a practical solution for managing steam that has already released its useful heat, helping convert it back into water in a controlled manner. This reduces thermal load in the machinery space, improves condensate management, and contributes to cleaner, more efficient operation of the overall steam circuit.
For an FPSO engine room installation, the design of the condenser must account for more than thermal duty alone. The unit should be compact enough for the available footprint, but still provide enough heat transfer surface to deal with the full steam load under tropical ambient and seawater-related operating conditions typical of Southeast Asia. Marine vibration, ship motion, accessibility for maintenance, and resistance to humid and corrosive conditions are all practical concerns. Material selection, venting arrangement, drain design, and support structure must therefore be aligned with offshore service requirements rather than standard land-based utility practice.
Another important point in FEED is the balance between conservative design and project cost. At the budgetary stage, the owner and EPC team usually need enough technical definition to understand the expected size, layout, material approach, and utility demand of the condenser, without yet freezing every detail. In this case, items such as the final tube-side medium, fouling allowance, preferred materials, nozzle orientation, class requirements, and engine room installation constraints would normally be confirmed during the next phase of engineering. Even so, the current process data is sufficient to begin preparing a budgetary proposal and preliminary thermal assessment.
From a vendor's perspective, this is a typical case where custom engineering adds real value. A properly designed atmospheric condenser for FPSO use should match the project's thermal load while also considering marine construction standards, transport limitations, and onboard installation practicality. Depending on the client's preference, the unit can be designed with materials suitable for offshore atmospheres and with a configuration that simplifies inspection and servicing over the vessel's operating life.
For FEED-stage evaluation, the following design basis can be taken as the starting point: shell-side exhaust steam flow of 90,000 kg/h, shell-side outlet temperature of 65°C, tube-side cooling medium flow of 1,180 m³/h to be confirmed by vendor, tube-side operating pressure of 2.0 barg, tube-side inlet temperature of 27°C, and tube-side outlet temperature below 40°C. Based on these parameters, the atmospheric condenser can be preliminarily sized for budget estimation and concept review.
In offshore energy projects, supporting equipment like atmospheric condensers may not attract as much attention as the boiler itself, but their role is fundamental. A well-designed condenser helps the steam system operate more efficiently, supports stable topside heating service, and reduces operational issues in the engine room. For a new FPSO conversion in Southeast Asia, selecting the right atmospheric condenser during FEED is therefore an important step toward a reliable and workable steam plant design.
