CFD SIMULATION OF FLUE GAS DUCTING IN WASTE HEAT RECOVERY PLANT

In the highly competitive metal production and power generation industries, the difference between energy recovered and energy wasted often determines the difference between profit and loss. A waste heat boiler is one of the devices generally employed to recover energy from high temperature furnace gases, extracting a significant fraction of waste energy. Waste Heat Recovery Boiler (WHRB) is the quintessential example of energy optimization in this age of renewal and energy saving. They capture the waste heat from the process systems and utilize it for other heating process, which ultimately increase the efficiency of plant. However, working stage of WHRB is challenging as design is prepared depending on site constraints and it is expected to deliver high efficiency even when dealing with high velocity and high temperature flows. CFD is widely used to investigate the flow pattern, pressure drop across ducting and particle trajectory within various equipment. CFD can be used to address problems with existing geometrical or performance errors like erosion of duct material due to ash particles, flow non-uniformity at tube bundles entry. Such problems may lead to lower efficiency of the equipment. Therefore, CFD can provide insight in the behavior of the system and contribute to resolving the problem. CFD has helped in improving the flow pattern by arrangement of baffles, flow separators at required locations within prescribed pressure drop across system, improving particle separation efficiency. In this works CFD is used to analyze & improve flow distribution inside the WHRS, which enhance the Thermal efficiency of the boiler, proper distribution of particles to avoid erosion of the tubes and optimization in the pressure drop in WHRS The geometry and mesh was created in Hypermesh & T-grid. The analysis was conducted using advanced CFD software tool, Fluent. Fluent has been applied extensively worldwide for different engineering applications. Fluent solves numerically the Navier-Stokes equations (the fundamental fluid dynamics governing equations). The discrete phase modelling is done by DPM Multiphase approach.