1.The heat used to fire the kettle reboiler at the bottom of the distillation column comes from a furnace. The walls of the furnace are built of a 150 mm of refractory of thermal conductivity...

1.The heat used to fire the kettle reboiler at the bottom of the distillation column comes from a furnace. The walls of the furnace are built of a 150 mm of refractory of thermal conductivity of







. The surface temperatures of the inner and outer faces of the refractory are 1400 K and 540 K respectively. An engineer on your team reckons that installing a layer of insulation could bring about a 50% reduction in heat loss. The engineering manager is excited at this prospect, as this could result in a significant reduction in operational costs. She has asked you to do the relevant calculations (and show all workings clearly) to verify or otherwise this claim, before taking any decisions.

If a 25 mm thick layer of the insulation material being proposed has a thermal conductivity of







, what temperatures will its surfaces attain if the inner surface of the furnace is to remain at 1400 K? What will be the percentage reduction in heat loss with the installation of the insulation? Write a report to the engineering manager, making your recommendations. The manufacturer manual for the insulation has the following coefficients of heat transfer from the outer surface of the insulation to the surroundings (at 290 K) at different temperatures in Table Q

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