CH301N: Chemistry in Our World Names: Section: FIRST-ORDER SYSTEMS (PART 2) 1. The liquid-level process shown is operating at steady state when the following disturbance occurs: At time t = 0, 1 ft3 water is added suddenly to the tank; at t = 1 min, 2 ft3 of water is added suddenly to the tank. Sketch the response of the level in the tank with time. Determine the level at t = 0.5, and 1.5 min. 2. A 200-L mixed tank heater is used to heat 25 L/min of water from 200C to 80oC. At t =0 min, the heating element malfunctions and was shutdown for 12 min. At t = 12 min, the heating element was switched back on, but was only capable of delivering heat at half the initial value. Determine the lowest temperature in the system and the time it would occur. Also, calculate the time at which the temperature inside the system increases back to 45oC. (Karla) 3. Dye for our new line of blue jeans is being blended in a mixing tank. The desired color of blue is produced using a concentration of 1500 ppm blue dye, with a minimum acceptable concentration of 1400 ppm. At 9 A.M. today the dye injector plugged, and the dye flow was interrupted for 10 min, until we realized the problem and unclogged the nozzle. Sketch the concentration of dye as a function of time. For how many minutes was the flow leaving the mixer off-specification (< 1400 ppm)? CHE 2130: Process Dynamics and Control Problem Set 7 Names: Larracas, Mikki P. Ninobla, Karla Marie SJ. Tanpoco, Sebastian Riley Section: 4ChE-A FIRST ORDER SYSTEM IN SERIES a. Two-mixed tank heaters in series are operating at steady-state as shown. At t = 0, the heater at the first tank is switched off temporarily for 5 min and switched back on right after. Calculate the temperature of the outlet of the second tank at t = 3 min and t = 8 min. b. In the two-tank mixing process shown, x varies from 0 lb salt/ft3 to 1 lb salt/ft3 according to a step function. At what time does the salt concentration in tank 2 reach 0.6 lb salt/ft3 ? The holdup volume of each tank is 6 ft3.