Development of converging-diverging multi-jet nozzles for molten smelt shattering in kraft recovery boilers

摘要

The effective shattering of molten smelt is highly desired in recovery boiler systems. Ideally,shatter jet nozzle designs should: i)generate high shattering energy;ii)create a wide coverage;and iii)minimize steam consumption. This study proposes a novel converging-diverging multi-jet nozzle design to achieve these goals. A laboratory setup was established,and the nozzle performance was evaluated by generating jet pressure profiles from the measurement of a pitot tube array. The results show that the shatter jet strength is greater with a large throat diameter,high inlet pressure,and a short distance between the nozzle exit and impingement position. Increasing the number of orifices generates a wider jet coverage,and the distance between the orifices should be limited to avoid the formation of a low-pressure region between the orifices. The study also demonstrates that an optimized convergingdiverging multi-jet nozzle significantly outperformed a conventional shatter jet nozzle by achieving higher energy and wider coverage while consuming less steam. Application: This paper showed the development of a shatter jet nozzle design that achieves better performance than traditional jets achieve. Readers can refer to this paper to understand the development process and theories behind the design. The data also allows future work to be conducted to further optimize the product.