Oxy-fuel combustion power plants use pulverized coal particles as fuel to burn in a pure oxygen environment to generate electricity. Before entering the furnace, pulverized spherical coal particles with an average diameter of 300 mm, are being transported at 2 m/s through a 3-m long heated tube while suspended in hot air. The air temperature in the tube is 900°C and the average convection heat transfer coefficient is 250 W/m²·K. Determine the temperature of the coal particles at the exit of the heated tube, if the initial temperature of the particles is 20°C.