Afirst order reaction is employed in a destruction kind of a
certain kind of microorganism. ozone is used as the disinfectant
and the reaction is found to be
dc/dt=-kc. where c is the concentration of microorganisms,
microbes/ml. k is the rate constant, and t is time, min.
the present system employs a completely mixed flow reactor and
there is some sort of baffling it to create a series of cmf
reactors.
a. if the objective is to increase the percentage microorganisms
destruction from 80% to 95%, how many cmf reactors are needed in
the series?

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.