Unit Operations Of Chemical Engineering
Unit Operations Of Chemical Engineering
7th Edition
ISBN: 9789339213237
Author: MCCABE, WARREN
Publisher: Tata McGraw-Hill Education India
Question
Book Icon
Chapter 10, Problem 10.1P
Interpretation Introduction

Interpretation:

The equivalent thickness of air layers in millimeters is to be calculated.

Concept Introduction:

The law of heat conduction states that the heat transfer rate through any material is proportional directly to the negative of the temperature gradient and the area of the heat flow.

  Q=kA(T2T1)x..... (1)

Here, x is the thickness of the material, T1 is the temperature of the hot side of the wall, T2 is the temperature of the cold side of the wall, A is the area of the heat conduction, and k is the thermal conductivity of the material.

For N materials present in series in a wall, the rate of heat transfer is taken same throughout the wall. The heat transfer equation will now become:

  Q=A(T2T1)iNxiki..... (2)

Expert Solution & Answer
Check Mark

Answer to Problem 10.1P

The air layer thickness is calculated as, xair=298 mm .

Explanation of Solution

Given information:

Thickness of the refractory fireclay brick, xA=200 mm

Thickness of the kaolin brick, xB=100 mm

Thickness of the steel pipe, xC=6 mm

Thin layers of air are between brick and steel.

Fire side refractory temperature, T1=1150C

Temperature of the outside of steel side, T2=30C

Heat loss from the wall per meter square of the wall, Q=300 Wm2

For the appendix 11, take the thermal conductivity of fireclay brick, kaolin brick, steel plate, and air as:

  kA=1.7 WmCkB=0.11 WmCkC=45.34WmCkair=0.11WmC

Let the thickness of air layer be xair . Use equation (2) for 1 m2 of wall area to calculate the air layer thickness as:

  Q=(T2T1)xAkA+xBkB+xCkC+xairkair300 Wm2=(30C1150C)200 mm×m1000 mm1.7 WmC+100 mm×m1000 mm0.11 WmC+6 mm×m1000 mm45.34WmC+xair0.11WmCxair=0.298 mxair=298 mm

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
مشر on ۲/۱ Two rods (fins) having same dimensions, one made of brass(k=85 m K) and the other of copper (k = 375 W/m K), having one of their ends inserted into a furnace. At a section 10.5 cm a way from the furnace, the temperature brass rod 120°C. Find the distance at which the same temperature would be reached in the copper rod ? both ends are exposed to the same environment. 22.05 ofthe
4.59 Using the unilateral z-transform, solve the following difference equations with the given initial conditions. (a) y[n]-3y[n-1] = x[n], with x[n] = 4u[n], y[− 1] = 1 (b) y[n]-5y[n-1]+6y[n-2]= x[n], with x[n] = u[n], y[-1] = 3, y[-2]= 2 Ans. (a) y[n] = -2+9(3)", n ≥ -1 (b) y[n]=+8(2)" - (3)", n ≥ -2
(30) 6. In a process design, the following process streams must be cooled or heated: Stream No mCp Temperature In Temperature Out °C °C kW/°C 1 5 350 270 2 9 270 120 3 3 100 320 4 5 120 288 Use the MUMNE algorithm for heat exchanger networks with a minimum approach temperature of 20°C. (5) a. Determine the temperature interval diagram. (3) (2) (10) (10) b. Determine the cascade diagram, the pinch temperatures, and the minimum hot and cold utilities. c. Determine the minimum number of heat exchangers above and below the pinch. d. Determine a valid heat exchange network above the pinch. e. Determine a valid heat exchange network below the pinch.
Knowledge Booster
Background pattern image
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Introduction to Chemical Engineering Thermodynami...
Chemical Engineering
ISBN:9781259696527
Author:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Publisher:McGraw-Hill Education
Text book image
Elementary Principles of Chemical Processes, Bind...
Chemical Engineering
ISBN:9781118431221
Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:WILEY
Text book image
Elements of Chemical Reaction Engineering (5th Ed...
Chemical Engineering
ISBN:9780133887518
Author:H. Scott Fogler
Publisher:Prentice Hall
Text book image
Process Dynamics and Control, 4e
Chemical Engineering
ISBN:9781119285915
Author:Seborg
Publisher:WILEY
Text book image
Industrial Plastics: Theory and Applications
Chemical Engineering
ISBN:9781285061238
Author:Lokensgard, Erik
Publisher:Delmar Cengage Learning
Text book image
Unit Operations of Chemical Engineering
Chemical Engineering
ISBN:9780072848236
Author:Warren McCabe, Julian C. Smith, Peter Harriott
Publisher:McGraw-Hill Companies, The