Operation Improvement, Reliability and Performance Optimization With Analysis and Simulation

Rapid development in computers has led to significant advancement in simulation technology. The analysis tools such as CFD and FEA are now household tools used for improving plant operations, building reliable equipment with enhanced safety features with an eye on improving and optimizing performance. In this paper a few case studies are selectively presented to demonstrate the value of these tools to the customer — improved efficiency, reduced schedule times and cost. These examples are chosen to show how these technologies are used to identify and mitigate any safety and operational risks associated with plant design and improve the design over the projects life cycle. The first example considers a design and operation improvement in a Heat recovery Steam generator (HRSG). To reduce material and equipment costs, it is very easy to design the HRSG with sharp corners and steep angles from one module to another and keep them closer to each other. This essentially reduces the overall efficiency of the plant due to gas turbine exhaust flow non-uniformity and re-circulation zones. The existing flow correction device consisting of 32 large tubes running across the sides produces a very large pressure drop. Using CFD, a flow distribution grid is designed, providing at least a 20% improvement in velocity distribution. The second example considers a coal burning boiler performance optimization. In this boiler upgrade project, CFD is used to confirm the feasibility of increasing the capacity and reducing the particulate emissions of the coal fired furnace and steam boiler units. Some of these factors were difficult to evaluate reliably using physical scale modeling techniques that were performed mainly only for cold flow pressure drop analysis. However the experimental results were used for benchmarking the CFD results. A third example shows how fluid dynamic analysis combined with thermal and structural analysis may be used to obtain the thermal fatigue life of various components of a molecular sieve dehydrator unit, where the design life is governed by the thermal loads generated during the regeneration cycle. Based on the fatigue analysis a more effective support is designed to withstand a higher flow capacity thus increasing production.