Keywords: after-burners, thermal stress, off-design, emissions, combined cycle plants, cogeneration plants, thermal design, duct burners, design optimisation, thermoduynamics, fluid dynamics, pressure drops, environmental technology, environmental impact
Thermal design and emissions of duct-burners for combined-cycle and cogenerative plants
This paper mainly aims at demonstrating that an appropriate thermo-fluid-dynamic design optimisation of duct-burners for combined-cycle and cogenerative plants allows to satisfy restrictive emission limits, while significantly reducing the thermal stresses and the undesired pressure drops. In particular, a detailed discussion on the influence of the TEG composition and of the thermal load, measured for a standard duct-burner, is proposed to justify component failure registered in plant applications. On this basis, the paper also addresses an important design criterion, usually neglected, which allows realisation of long-life and maintenance-free duct-burners, while retaining the fundamental requirement of limiting emissions. Finally, the influence of the thermal load on the emissions produced by the modified duct-burner has been experimentally measured, and analysed, with the aid of some numerical computations.