A 10% by weight NaOH solution is being used for a caustic washing process. In order to smooth the variations in flow rate and concentration, a 10,000 gallon tank is being used as a surge tank (well mixed). The washing process requires a constant flow rate of 1500 gal/hr of the solution. Just before a plant upset, the tank contains 8000 gallons of a 10% NaOH solution, with an inlet flow to the tank of 1000 gal/hr of a 10.5% NaOH solution. Due to the upset, the inlet stream concentration drops to 5% NaOH instantaneously although the flow rate remains constant. An alarm will sound to warn the operator when the outlet concentration from the surge tank drops to 9.8% (or rises to 10.2%). The tank is well mixed and the density of all solutions is 8.3 lb/gal. All concentrations given above are on a weight basis. Find: a) how long it will take before the alarm sounds? b) if the alarm did not operate, how long it would take before the surge tank was empty?

m Water is flowing with a velocity of 0.914" on a flat plate of width 0.305 m at 20°C. (i) Calculate the type of flow, Reynolds number and (ii) calculate the boundary layer thickness at 0.305 m. a) (i)Re = 2.77x10' (ii) 0.00204 m b) (i)Re = 2.77×10 (ii)0.0029 m c) (i)Re = 2.77x1o° (ii)0.00204 m d) (i)Re = 1.87x10o° (ii)0.0035 m

pound (force) are not the same units in the AE system. Example 4 What is the potential energy in (ft)(1bf) of a 100 lb drum hanging 10 ft above the surface of the earth with reference to the surface of the earth? Solution

A manufacturing process uses the powerful solvent acetone. One phase of the process is to dry out the acetone in a drying area. The drying area evaporates 2 gallons of acetone per hour. Every gallon of liquid acetone produces 41 cubic feet of vapor. Calculate the amount of ventilation (cubic feet/hour) needed to maintain vapor concentration below the burnable level. How many times per hour would the ventilation system exhaust a room 9 feet by 12 feet with a ceiling height of 10 feet?

A cylindrical tank is vented to the atmosphere that serves as a reservoir for octane before itis piped to another location is 140 ft in diameter. Determine the pressure difference betweenthe top and bottom of the walls due to the octane when the tank is filled to a depth of 30 ft(9.14 m). Why is the vent necessary?NB: Atmospheric conditions are such that the pressure is 1atm and temperature 25 oC. SG ofoctane is 0.701

Given information is attached. A. Neglect friction and calculate the velocity at point 2. (Velocity in m/s) B. If the pipe diameter at point 2 is 7.00 cm, what is the diameter at point 1? (Diameter in cm)

Design a hydrocooling unit that can cool fruits and vegetables from 30°C to 5°C at a rate of 20,000 kg/h under the following conditions: The unit will be of flood type that will cool the products as they are conveyed into the channel filled with water. The products will be dropped into the channel filled with water at one end and picked up at the other end. The channel can be as wide as 3m and as high as 90 cm. The water is to be circulated and cooled by the evaporator section of a refrigeration system. The refrigerant temperature inside the coils is to be –2°C, and the water temperature is not to drop below 1°C and not to exceed 6°C. Assuming reasonable values for the average product density, specific heat, and porosity (the fraction of air volume in a box), recommend reasonable values for the quantities related to the thermal aspects of the hydrocooler, including how long the fruits and vegetables need to remain in the channel, the length of the channel, the water velocity through…

21. A large containment is filled with steam, air, and nitrogen. The containment also has a pool of water, which is sprayed in the containment atmosphere. Heat is added to the con- tainment at a specified rate. Use the given data to find a) the initial containment pressure and b) the time it takes for the containment pressure to reach the pressure limit of 145 psia (1 MPa). Total mass of water (water in the pool and steam) m,, = 3.42E6 lbm (1.55E6 kg) Water-steam quality x = 0.03 Air mass m, = 0.132E6 lbm (6E4 kg) Nitrogen mass m, = 2200 lbm (998 kg) Containment initial temperature T; = 688 R (109 C) Initial relative humidity ø = 100% Rate of heat addition to containment atmosphere Q = 1.02E8 Btu/h (30 MW) [Ans.: 7.66 h].

You work in a chemical plant which recovers gold from gold-plated electrical connectors using heated (Tacid = 55oC) nitric acid.  Once the acid is “used up” it gets piped through the plant to a separate facility for disposal.  During that time, it passes through a cooling chamber to strip the waste heat off the acid for recovery.  The acid passes through the chamber in 6m long, 400mm OD, 360mm ID aluminum tubes. The chamber passes room-temperature air over the tubes at 8 m/s.  Approximately 0.45 cubic meters of acid is processed per hour. a) What is the Reynold’s number of the nitric acid passing through the tube?  Is it turbulent or laminar? b) What is the heat transfer coefficient of the nitric acid to the inside of the aluminum tube? c) What is the heat transfer coefficient of the air over the tube? d) What is the overall heat rate from the nitric acid to the air? e) Based on your answers here, in a gas-liquid heat exchanger, which side of the exchanger are the fins usually on?…

Please help me with part B. Thanks!