What temperature differentials are associated with fixed head and floating head heat exchangers.
What will be an ideal response?
Ex-202 and Ex-203 are characterized as shell and tube, multi-pass, floating head heat exchangers. Floating head heat exchangers are designed for high temperature differentials above 200ºF. During operation, one tube sheet is fixed and the other “floats” inside the shell. The floating end is not attached to the shell and is free to expand. Engineering specifications take into account thermal tube expansion or tube growth. The tube sheet on the channel head is fixed on both Ex-202 and Ex-203. The floating head creaks as it slowly expands during start-up. The exchangers in this system are classified as two-pass devices. The shell side of Ex-202 is connected in series flow to the shell side of Ex-203. Tube side flow on Ex-202 comes from the bottom of the distillation column, while the tube side of Ex-203 is connected to the hot oil system. The heat exchanger system described in this chapter is illustrated by Figure 10-2 Heat Exchanger System.
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Which of the following should you be aiming for in your job?
A) Low ability/high interest B) Low ability/low interest C) High ability/low interest D) High ability/high interest
A distillation unit is to be used to generate pure water vapor. 5.0 lbm/s of liquid water at 100oF enters the system, and 1.0 lbm/s of saturated water vapor leaves through one port and 4.0 lbm/s of saturated liquid leaves through a second port (along with impurities in the water which can be neglected in the analysis). The pressure throughout the whole system is 20 psia. A stirring system is used, which is powered by a 0.4 hp motor – assume that all of the motor’s work enters the system. All other energy is added through heat transfer.
(a) Determine the rate of heat transfer needed to produce this flow of saturated water vapor. (b) Using your separation chamber model, plot the heat transfer rates needed to produce saturated water vapor flow rates between 0.5 lbm/s and 4.0 lbm/s (along with corresponding changes to the saturated liquid water exit flow rates). State 1: Inlet stream; State 2: Saturated vapor exit stream; State 3: Saturated liquid exit. Given: P1 = P2 = P3 = 20 psia; T1 = 100oF; x2 = 1.0; x3 = 0.0; m?1=5.0lbm/s; m?2=1.0lbm/a; m?3=4.0lbm/a; W?=?0.4 hp=?0.283 Btu/s Assume: Given no other information regarding the mixing chamber, make the following common assumptions: ?KE=?PE=0. We are told there is heat transfer. Also, assume the mixing chamber is a single-inlet, multiple-outlet, steady-state, steady-flow device. What will be an ideal response?
What is the most common insulating material used on conductors?
A. copper B. silk C. aluminum D. plastic
Find the area under the normal curve
a. To the left of z = 0.56. b. Between z = –2.93 and z = –2.06. c. Between z = –1.08 and z = 0.70. d. Outside z = 0.96 to z = 1.62.