Question

A shell and-tube heat exchanger is required for the following service: Hot stream Cold Stream Aromatic...



A shell and-tube heat exchanger is required for the following service:

Hot stream Cold Stream
Aromatic Stream Cooling Water
inlet Temperature (oC) 85 20
outlet Temperature (oC) 40 35
Mass Flowrate x heat Capacity (kW/oC) 85.2
Hot Stream cold stream (Cooling water)
Heat Capacity (J/kg K) 2840 4193
Density (kg/m3) 750 999
Viscosity (cP) 0.34 1.016
Thermal conductivity (W/m.K) 0.19 0.594
Fouling Factor (m2.oC/W 0.00018 0.000176


? The cooling water is allocated to the tube-side of the exchanger.
? It is preferable to employ a fixed-tubesheet heat exchanger for the service.
? 25.4 mm OD tubes (2.1 mm wall thickness) on a 1.25 x OD triangular pitch are available. The
thermal conductivity of the tube material is kw = 51 W/m?K.
? Consider four (4) tube passes.
? The maximum tube length that can be employed is 6.098 m i.e. L < or = 6.098 m
? Assume 1-shell pass. The shell diameter should not exceed 1.5 m i.e. Ds < or = 1.5 m
? Baffle cut is set at 25% and the baffle spacing (lb) is assumed to be 0.5 x Ds
? The maximum allowable tube-side and shell-side pressure drops are 70 kPa and 50 kPa
respectively.
? Total annual cost (TAC) is given as follows:
TAC = 123 A^(0.59) + 1.31 [ delta Ptube . mtube/ densitytube + delta Pshell . mshell/ densityshell ]
where A is the area of the exchanger in m2, TAC is in $/year, ?delta P is in Pa, m in kg/s and density? in
kg/m3

2.2 Provide a mathematical expression for the following constraints:
o the tube side velocity,
o the shell-side velocity, and
{Hint: Note: cooling water in the tubes}


2.3 Derive an expression for the number of tubes in terms of the tube-side velocity, number of tube
passes, mass flowrate and tube inside diameter.

2.4 Calculate the number of tubes at the minimum and maximum tube-side velocities
2.1). Show the calculations and summarise your answers in a table.
{It is convenient to use a spreadsheet for this calculation}


2.5 For each of the number of tubes calculated in 2.4, determine the shell diameter Ds. (you can fit a straight
line to the data if you would rather like to use an equation). Show the calculations and summarise
your answers in a table.

2.6 Plot a graph of tube length vs shell diameter for the minimum and maximum velocity as well as
the maximum shell diameter. Discuss your findings.


2.7 Select various shell diameters between the limits found in Coulson. {4 to 5 values should be sufficient}.
For each shell diameter, determine the tube length at the maximum tube-side pressure drop.
Show the calculations and summarise your answers in a table.


2.8 Using the same shell diameters selected in 2.7, determine the tube length at the maximum shellside
pressure drop. Show the calculations and summarise your answers in a table.
2.9 For each shell diameter, determine the tube length based on the heat transfer duty i.e. Q=UA?Tm
{You need to determine the heat transfer coefficients on the tube and shell-side}. Show the
calculations and summarise your answers in a table.
2.10 Plot your results from 2.7, 2.8 and 2.9 on a graph of tube length (x-axis) vs shell diameter (yaxis).
{Please use a spreadsheet to do this. Do not submit hand-drawn plots}. Identify the feasible
region.
2.11 Determine the exchanger with the minimum cost. Discuss your approach and findings.
2.12 How does the above approach of exchanger design compare/contrast with the standard
method?

Homework Answers

Answer #1

A-2.4)

Ovrall HTC 600 W/m2K Taken from R c vol. 6
Tube ID (di) 19 mm
No. of Tube pass 4
Mass flow rate 30 kg/sec
Heat Transfer Area 260 m2
Tube Length Tube Side velocity No. of Tubes
1.83 0.237085 2381.437
2.44 0.316113 1786.077
3.66 0.474170 1190.718
4.88 0.632227 893.039
6.1 0.790283

714.431

A-2.5

Tube Length Tube Side velocity No. of Tubes Tube Bundle Dia Clearance Shell Dia
1.83 0.237085 2381.437 1636.5790 NA -
2.44 0.316113 1786.077 1442.9763 80 1522.9763
3.66 0.474170 1190.718 1208.3568 77 1285.3568
4.88 0.632227 893.039 1065.4116 73 1138.4116
6.1 0.790283 714.431 966.2867 71.5 1037.7867

WHere k1=0.175 & N1=2.285 for 4 passes at tube side

FOr Tube bundle shell clearance refer graph 12.10 and for tune bundle dia refer table no. 12.4 of RC vol.6

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
Water at a flow rate of 60 kg/s enters the shell-side of a baffled shell-and-tube heat...
Water at a flow rate of 60 kg/s enters the shell-side of a baffled shell-and-tube heat exchanger at 35 °C and leaves at 25 °C. The heat will be transferred to 150 kg/s of raw water coming from a supply at 15 °C. You are requested to design the heat exchanger for this purpose. A single shell and single tube pass is preferable. The tube diameter is ¾ in. (19 mm outer diameter with 16 mm inner diameter) and tubes...
A 1-shell-2-tube pass heat exchanger is made of a steel alloy (thermal conductivity 45.4 W/(m K)....
A 1-shell-2-tube pass heat exchanger is made of a steel alloy (thermal conductivity 45.4 W/(m K). It is used to cool distilled water from 34oC to 29oC using water which flows inside tubes with an outer diameter of 19 mm and an inner diameter of 16 mm. The number of tubes in the shell is 160 (80 per pass). The mass flow rate of distilled water in the shell is 76180 kg/h. The cold water enters the heat exchanger at...
A horizontal shel-and-tube heat exchanger with two tube passes and one shell pass is being used...
A horizontal shel-and-tube heat exchanger with two tube passes and one shell pass is being used to heat 9 kg/s of 100% ethanol from 25 to 65 C at atmospheric pressure. The ethanol pasar through the inside of the tubes, and saturated steam at 115 C condenses an the shell of the tubes. The tubes are atell with an OD of 0.019 m and a BWG of 14. The exchanger contains a total of 100 tubes (50 tubes per pass)....
Question 2. Answer all parts of this question a) A shell and tube heat exchanger is...
Question 2. Answer all parts of this question a) A shell and tube heat exchanger is to heat 10,000 kg h–1 of water from 16 to 84°C using hot oil entering at 160°C and leaving at 92°C. The oil will flow through the shell of the heat exchanger. The water will flow through 11 brass tubes of 22.9 mm inside diameter and 25.4 mm outside diameter, with thermal conductivity 137 W m–1 K–1, with each tube making two passes through...
A 1 to 2 baffled shell-and-tube type heat exchanger is used as an engine oil cooler....
A 1 to 2 baffled shell-and-tube type heat exchanger is used as an engine oil cooler. Cooling water flows through tubes at 25 °C at a rate of 8.16 kg/s and exits at 35 °C. The inlet and outlet temperatures of the engine oil are 65 and 55 °C, respectively. The heat exchanger has 12.25-in. I.D. shell, and 18 BWG and 0.75-in. O.D. tubes. A total of 160 tubes are laid out on a 15/16-in. triangular pitch. By assuming Ro...
A 1 shell pass, 4 tube pass shell-and-tube heat exchanger is used to cool therminol 59...
A 1 shell pass, 4 tube pass shell-and-tube heat exchanger is used to cool therminol 59 in a refinery. The therminol 59 enters the tubes at a mass flow rate of 0.87 kg/s and changes in temperature from 93◦C to 49◦C. Water is the other fluid. It enters the shell at a mass flow rate of 1.20 kg/s, and changes in temeperture from 23◦C to 37.1◦C. Determine the following: (a) (10 pts) The heat transfer between the two fluids (b)...
The condenser of a large steam power plant is a heat exchanger in which steam is...
The condenser of a large steam power plant is a heat exchanger in which steam is condensed to liquid water. Assume the condenser to be a parallel flow shell-and-tube heat exchanger consisting of a single shell and 10,000 tubes, each executing two passes. The tubes are of thin wall construction with D = 30 mm and the steam condenses on their outer surface. The heat transfer rate that must be effected by the exchanger is Q = 2 × 10^9...
Data for carbon dioxide: Molecular weight:44.0 Heat capacity of gas phase: 0.036+4.23 x10-5T   (in kJ/moleoC, T is...
Data for carbon dioxide: Molecular weight:44.0 Heat capacity of gas phase: 0.036+4.23 x10-5T   (in kJ/moleoC, T is in oC) Viscosity                                 Pr                    k (W/m K) 180oC2.13 x10-5kg/(m s)                  0.721               0.029 130oC  1.93x10-5kg/(m s)                  0.738               0.025   80oC  1.72x10-5kg/(m s)                  0.755               0.020 Approximate density: 2.0 kg/m3 Data for water: Molecular weight:18.0 Heat capacity for liquid water: 0.0754 kJ/mole oC   Viscosity: Viscosity                                 Pr                    k (W/m K) 180oC139 x10-6kg/(m s)                   0.94                 0.665 130oC  278x10-6kg/(m s)                   1.72                 0.682   80oC  472x10-6kg/(m s)                   3.00                 0.658 Ideal gas constant: 0.08206 L atm/(mol K) Carbon dioxide, with flow rate of 0.10 kg/s, is to be cooled from 180 oC to 80...
A concentric tube heat exchanger is comprised of a stainless steel (ks = 40 W/mK) inner...
A concentric tube heat exchanger is comprised of a stainless steel (ks = 40 W/mK) inner pipe, NPS 2- nominal schedule 40 size (corresponding to an inner diameter of 52.5 mm and an outer diameter of 60.3 mm), and an outer stainless steel pipe of NPS 3-nominal schedule 40 (ID = 77.9 mm, OD = 88.9 mm). The heat exchanger has an effective length of 35 m. The inner pipe fluid is ammonia (?a = 0.3 · 10?6 m2/s, cpa...
A concentric tube heat exchanger is comprised of a stainless steel (ks = 40 W/mK) inner...
A concentric tube heat exchanger is comprised of a stainless steel (ks = 40 W/mK) inner pipe, NPS 2- nominal schedule 40 size (corresponding to an inner diameter of 52.5 mm and an outer diameter of 60.3 mm), and an outer stainless steel pipe of NPS 3-nominal schedule 40 (ID = 77.9 mm, OD = 88.9 mm). The heat exchanger has an effective length of 35 m. The inner pipe fluid is ammonia (va = 0.3 · 10-6m2/s, cpa =...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT