HRSG Technologies

Downer Energy Systems (DES) has the capability and experience to deliver HRSG's and associated plant, matched to Gas and Steam Turbines provide optimal performance and reliability.

A license agreement with NEM bv of the Netherlands, provides DES with access to 'state of the art' technology for HRSG's behind Gas Turbines. NEM is a world leader in this field with over 20% of market share.

Downer Engery Systems is able to offer customers a comprehensive range of designs, such as:

Horizontal Gas Flow, Natural Circulation

In this design, the hot flue gases flow horizontally from the turbine through banks of finned tubes aligned vertically ie at 90 degrees to the flow. Circulation from the drum positioned on top of the boiler is via downcomers then up through the evaporator.

Vertical Gas Flow, Forced Circulation

With this design the horizontal gas flow from the turbine is directed vertically through the boiler, with the hot gases flowing through banks of finned tubes aligned horizontally ie at 90 degrees to the flow. Pumps ensure the water/steam circulation through the tubes.

Vertical Gas Flow, Natural Circulation

This design is similar in many respects to the forced circulation type described above, however natural circulation is ensured by selecting the correct combination of pressure loss over the evaporators, circulation ratios, and drum height relative to the evaporator. In all cases, the entire boiler is top suspended from the steel structure and in the case of vertical gas flow boilers, the stack is supported on top of the structure.

Based on the license technology from NEM supported by a rich source of experience and practical data from past projects, the boiler designs are optimised to suit specified performance and long term reliability. Fast start up plants can be designed based on determination of static & dynamic loading of pressure parts, and this experience in turn enables meaningful advice on start up & shut down procedures. Flow testing of inlet ducting is crucial to ensure correct gas flow through the tube banks, and is particularly important in the duct itself to achieve satisfactory flow for duct burners - if applied.

DES has experience with supplementary firing, and with fresh air firing alone. This is particularly of benefit for process steam plants where reliable steam supply is crucial.

DES can supply total steam plant packages, either for CCPP or cogeneration purposes. These are based on an HRSG, together with any special firing regimes, auxiliary boiler, diverter damper, etc tailored to meet customer needs. DES can also supply GT inlet & exhaust systems including filter houses, inlet cooling, cold & hot silencers, expansion joints and exhaust stacks.

Total Capability

Complete HRSG packages can be engineered, supplied, & installed "in-house" using extensive facilities & capabilities of Downer-EDI Group sister Companies, including civil works, heavy module & component fabrication, instrumentation and control, electrical equipment, and mechanical and electrical installation.