Shell and Tube Heat Exchanger Design Using Htri Software

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SHELL AND TUBE HEAT EXCHANGER DESIGN

USING HTRI SOFTWARE

Group 1

Mulyawan Haditomo 1206291720 Ghifari Syuhada 1306387802 Anantama Karis Fadila 1306387815 Luthfi Rizki Perdana 1306437334

DEPARTMENT OF MECHANICAL ENGINEERING

FACULTY OF ENGINEERING

UNIVERSITY OF INDONESIA

2017

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i CONTENTS TABLE OF FIGURES ... ii CHAPTER 1 ... 1 INTRODUCTION ... 1 1.1 Background ... 1 1.2 HTRI Software... 1 1.3 Thesis Source ... 2 CHAPTER 2 ... 3 DESIGN PROCEDURE... 3

2.1 Manual Calculations Input ... 3

2.2 HTRI Data Input ... 7

CHAPTER 3 ... 12

RESULT ... 12

3.1 Comparison & Analysis ... 12

CHAPTER 4 ... 16

CONCLUSION ... 16

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ii

TABLE OF FIGURES

Figure 1 HTRI Xchanger suite 6.0 interface ... 2

Figure 2. Table of Corection Factor ... 4

Figure 3. Table of K1 and n1 constant ... 5

Figure 4. Bundle Clearance Graph ... 6

Figure 5. Input summary interface ... 7

Figure 6. Tube geometry interface ... 7

Figure 7. Process of working fluids interface ... 8

Figure 8. Kerosene component interface ... 8

Figure 9. Inserting manual fluid properties ... 9

Figure 10. Inserting manual Kerosene properties ... 9

Figure 11. Crude Oil Component Interface ... 10

Figure 12. Inserting manual fluid properties ... 10

Figure 13. Inserting manual Crude Oil properties ... 11

Figure 14 Output summary from HTRI software ... 12

Figure 15 Shell and tube design from Adi’s thesis ... 13

Figure 16 Shell and tube design from HTRI software ... 13

Figure 17 Tube arrangement from Adi’s thesis ... 14

Figure 18 Tube arrangement from HTRI software ... 14

Figure 19 Designed shell and nozzle from Adi’s thesis ... 15

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CHAPTER 1 INTRODUCTION 1.1 Background

It has been observed that manual calculations often become lengthy and iterative. HTRI has a rigorous and integral approach which gives more accurate results compared to manual calculations. HTRI is the most widely used software in the industry namely heat exchanger manufacturing industry. But it is also important to verify the results with manual calculations. In the same way, manual design should also be verified with industrial software like HTRI. It may happen sometimes that due to human error, manual design results may come out to be somewhat inaccurate. So, in order to have a good and optimized design, manual and software based calculations should be carried out simultaneously and verified with each other [1].

By using kern method for thermal calculation and number of iteration were done manually in Adi Indra’s thesis, then the results are being compared and analyzed in HTRI software. Hence, a better performance of shell and tube type heat exchanger can be obtained. Both the design of heat exchanger done by using HTRI and Adi Indra’s thesis are compared. It is predicted that many values (for example: number tubes) of the heat exchanger are assumed to change in HTRI as compared to the tube obtained during manual calculation.

The result from this report will visualize the output of both methods and therefore the feasibility of Adi Indra’s method of designing heat exchanger can be observed.

1.2 HTRI Software

The software used in this report is HTRI Xchanger Suite® Version 6.0. HTRI’s calculation methods are backed by 50 years of extensive research and data collected on industrially relevant heat transfer equipment. There are many features that can be done by using HTRI besides including components of heat transfer for calculating the design of heat exchangers and fired heaters. For instance, the results can also create graphs and scale drawings in-depth visualization of calculated results. Moreover, the extensive output reports can also provide the detailed results including local profiles of all important parameters, etc [2].

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2 There are different types of component that HTRI can simulate; a total of 9 components can undergo various simulations. To name some, a Xace can simulate, rate and design an air cooler or economizer. Whereas Xfh can simulate the performance of cylindrical and box heaters. In our case, a Xist component is used to design the shell-and-tube heat exchanger with known values of temperature inputs, flow rate, geometry of tube, shell, and baffles, etc [2].

1.3 Thesis Source

The manual calculations are done in thesis of Adi Indra Winata with the title of “Designing Shell and Tube Heat Exchanger of Fixed Head Type Using 3D Template Design” the thesis was done as one the prerequisites of completing the mechanical engineering bachelor degree in Universitas Indonesia. The thesis was done in 2008 with the objective of creating a method of automatic design integrated with the manual calculations from VBA Microsoft excel to output a CAD drawing of the heat exchanger.

By creating the method of automatic 3D design template, the goal is to create a designed heat exchanger in its optimum manner with a relatively quick process.

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CHAPTER 2 DESIGN PROCEDURE 2.1 Manual Calculations Input

Based on the thesis of Adi Indra the fluids that are used for designing the heat exchanger are crude oil and kerosene. The specifications for the design are stated below

Table 1. Fluids Temperature

Hot Fluid Kerosene

Temperature Inlet (Th1) 200oC Temperature Outlet (Th2) 90oC

Flow Rate (mh) 20000 kg/hr

Cold Fluid Crude Oil Temperature Inlet (Tc1) 40oC

Flow Rate (mc) 70000 kg/hr

Then we can calculate the Temperature Outlet (Tc2) for the cold fluid by using

Mean temperature of kerosene = (200 + 90)/2 = 145oC Cp = 2.47 KJ/kgoC

From the temperature above the mechanical properties of the fluids are

Table 2. Fluids Properties

Fluids Properties Kerosene (Hot Fluid) Crude Oil (Cold Fluid)

Inle / Outlet Temp(C) 200 90 40 78

Flow Rate (Kg/hr) 20000 70000

Cp (KJ/kg.C) 0.027 0.0023 2.09 2.01

Thermal cond. (W/m.C) 0.13 0.135 0.133 0.135

Viscosity (mN-s/m2) 2.2001 8.0003 0.2402 0.4299

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4 From the known temperature, we can try to calculate the LMTD for the heat exchanger

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Temperature correction factor

Figure 2. Table of Corection Factor

From the table of correction factor, we can get the value (Ft) = 0.87

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5 It has been determined that the shell and tube heat exchanger used is a fixed head type. And because the crude oil is dirtier than kerosene, then it is determined that the crude oil will be inside the tubes while the kerosene inside the shell. Layout and the tube dimension are determined as follows:

Tube diameter (do) = 19.05mm (3.4 inch) Tube thickness (t) = 2.11mm

Tube length (L) = 5m Tube pass = 2

Shell pass = 1 Layout = Triangular

We can calculate the pitch by using

We can calculate the number of tubes by using

After calculating the number of tubes we can use the value to calculate diameter bundle (Db) which then will be used to find the shell diameter

From the table, we can get the value

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6 Inserting the value to the equation

To calculate the shell diameter, we can use

Ds = Db + BDC

Where BDC is bundle diameter clearance from graph

Figure 4. Bundle Clearance Graph

In this case, we use the fixed and U-tube type which give the BDC = 12 mm

Ds = 428 + 12 = 440mm

From the calculation above we can input the data to HTRI

Table 3. Parameter

Shell ID (mm) 440

Baffle Type Single segmental

Baffle cut (% ID) 25

Tube Length (m) 5 Tube OD (mm) 19.05 Pitch (mm) 23.81 Wall thickness (mm) 2.108 Tube passes 2 Shell passes 1 Layout Triangular (30o)

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2.2 HTRI Data Input

In designing heat exchanger with HTRI software, initial data is needed to be input. Some has to be determined first, and some will be calculated. To begin with the data input, select the case mode to determine whether the case is designing or rating a heat exchanger. Input the process conditions in the input summary tab from the data available beforehand. Then, input the shell geometry and tube geometry, as well as baffle geometry.

Figure 5. Input summary interface

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Figure 7. Process of working fluids interface

Next, is determining the properties of the working fluids which will be used. It is determined that Kerosene will work as hot working fluid and Crude oil as cold working fluid. However, since there are no properties of the working fluid available in HTRI software for Kerosene and Crude Oil, the properties of fluids should be inserted manually to the library.

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Figure 9. Inserting manual fluid properties

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Figure 11. Crude Oil Component Interface

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CHAPTER 3 RESULT 3.1 Comparison & Analysis

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13 Above is the output summary of the designed heat exchanger with all the data available beforehand in Adi’s thesis. Compared with Adi’s manual calculation, the output is different. For the TEMA type of shell geometry, based on Adi’s design result the TEMA type can be categorized as BEM.

Figure 15 Shell and tube design from Adi’s thesis

Figure 16 Shell and tube design from HTRI software

The picture above shows the heat exchanger design from Adi’s thesis and HTRI software. The upper one is Adi’s designed heat exchanger and the second one is from HTRI software. In 5 meters long of designed shell, the number and spacing of the baffle is differ from each other. It could be caused by the calculation method which is also different. In Adi’s thesis, the calculation is done manually with all the formula given in text book, while in HTRI software might have a different way of calculation that might be more accurate as well.

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Figure 17 Tube arrangement from Adi’s thesis

Figure 18 Tube arrangement from HTRI software

In tube arrangement, the arrangement from those 2 sources is different. With using triangular (300) for both of the tube arrangement, the output design differ. The pitch is calculated differently from Adi’s thesis and HTRI software and concluded with different value. The number of tube is also different, from Adi’s thesis calculation it is shown that it has 240 tubes with 120 tubes in each pass, while the calculation from HTRI shown that it has 316 tubes with 158 tubes in each pass.

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Figure 19 Designed shell and nozzle from Adi’s thesis

Figure 20 Designed shell and nozzle from HTRI software

Above is the picture of the output 3D design of the shell of a shell and tube heat exchanger. From the picture, the 3D design is not significantly different, where only the baffle spacing and number are different. Both designs are two pass shell and tube.

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CHAPTER 4 CONCLUSION

As conclusion, HTRI software is quite easy to use if all the required data is available. Adi’s thesis design calculation is based on all the formula that is in text book. The use of all formula is depended on the type of TEMA, the flow of fluids, tube arrangement, shell and tube geometry and etc. Adi’s thesis only works for particular category of shell and tube, while HTRI software covering all the categories of heat exchanger. The manual calculation in Adi’s thesis is different from HTRI. There are some variable that might be using different formula that resulting in different value.

It is much easier to use HTRI as a software to design a shell and tube heat exchanger as it has many variables that can be inputted to get an efficient design. And it can directly become drawing which are exchanger drawing, tube arrangement drawing, 3D exchanger drawing, this can help us to understand our design better.

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REFERENCES

[1] S. Sahajpala and P. D. Shahb, Thermal Design of Ammonia Desuperheater-Condenser and Comparative Study with HTRI, Elsevier Ltd, December 2013.

[2] Heat Transfer Research, Inc., "HTRI Xchanger Suite | HTRI," [Online]. Available: https://www.htri.net/htri-xchanger-suite. [Accessed 20 May 2017].

[3] A. I. Winata, "Perancangan Shell And Tube Heat Exchanger Tipe Fixed Head Dengan Menggunakan Desain 3D Template," Universitas Indonesia, Depok, 2008.

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