After successfully completing the technology transfer of the Air Cooled Condenser (ACC) from our partner Innospin AG, design of ACC for the Dalahoo project’s difficult specifications has begun. Design specifications, such as very low backpressure, very low load operation, icing problems, etc., have made the project very complicated and necessitated the updating and improving of our technical knowledge to the latest level in order to overcome these unusual design conditions.
Due to the very large size of the steam duct (around 8 meters diameter), the design of this type of steam distribution system was very important to provide a uniform distribution of steam throughout the condenser streets, a uniform flow pattern within the system, and minimal pressure drop. This was achieved through a modern design and verified by Computational Fluid Dynamics (CFD) study.
A large amount of effort was needed to conduct the analysis of forces and moments produced during thermal expansion of the unit in order to find the optimum solution for compensation of large scale forces on the steam turbine exhaust.
To do this, a large transition piece converts the rectangular section of the turbine exhaust flange to the circular shape of the steam duct. This section has been designed for very smooth steam flow to prevent generating of eddies and vortices which can impose high levels of flow induced vibration.
The condenser includes 6 streets and 7 modules in each street which dissipates 410 MW heat to the surrounding in design conditions. The thermo-hydraulic calculation was performed by a modern in-house software developed by Innospin with the capability to check and evaluate various different operating off-design cases. This modern software provided solutions to optimize the heating surfaces and fan power consumption together with noise reduction.