GAS GAS HEAT EXCHANGER (HXG)

EXPERIMENT MODULE

CHEMICAL ENGINEERING EDUCATION LABORATORY

GAS – GAS HEAT EXCHANGER

(HXG)

CHEMICAL ENGINEERING

FACULTY OF INDUSTRIAL TECHNOLOGY

INSTITUT TEKNOLOGI BANDUNG

2018

INSTRUCTIONAL LABORATORY

CHEMICAL ENGINEERING FTI - ITB

MODUL PENUKAR PANAS GAS-GAS (HXG)

HXG – 2016/PW 2

Kontributor:

Dr. Dendy Adityawarman, Pri Januar Gusnawan, S.T., M.T., Dr. Ardiyan Harimawan, Ibrahim A.

Suryawijaya, Corelya Erindah A., Darien Theodric




HXG – 2016/PW 3

TABLE OF CONTENTS

TABLE OF CONTENTS ................................................................................................................. 3

LIST OF FIGURES .......................................................................................................................... 4

LIST OF TABLES ........................................................................................................................... 5

CHAPTER I PREFACE ................................................................................................................... 6

CHAPTER II EXPERIMENT GOALS AND OBJECTIVES ......................................................... 7

I. Goals...................................................................................................................................... 7

II. Objectives .......................................................................................................................... 7

CHAPTER III RANCANGAN PERCOBAAN ............................................................................... 8

I. Equipment Layout ................................................................................................................. 8

II. Supporting Equipments and Materials .............................................................................. 8

CHAPTER IV WORKING PROCEDURE ..................................................................................... 9

I. Working Procedure ............................................................................................................... 9

II. Measurement Methods .................................................................................................... 10

BIBLIOGRAPHY .......................................................................................................................... 11

APPENDIX A RAW DATA TABLE ............................................................................................ 12

APPENDIX B CALCULATION PROCEDURE .......................................................................... 13

APPENDIX C SPECIFICATION AND LITERATURE DATA ................................................... 17

I. Literature Data..................................................................................................................... 17

II. Equipment Specification (HXG) ..................................................................................... 17




HXG – 2016/PW 4

LIST OF FIGURES

Figure 1. HXG equipment layout. .................................................................................................... 8

Figure 2. Experiment procedure. ...................................................................................................... 9

Figure 3. Correction factor for ΔT for cross-flow type of heat exchanger (McCabe, 1993). ........ 14




HXG – 2016/PW 5

LIST OF TABLES

Table 1. Flowrate calibration data. ................................................................................................ 12

Table 2. Data for determining τ value. ........................................................................................... 12

Table 3. Main experiment data. ...................................................................................................... 12

Table 4. HXG equipment specification. ......................................................................................... 17




HXG – 2016/PW 6

CHAPTER I

PREFACE

Heat transfer is one of the most decisive factors in the operation of a chemical plant. Quantitative

solution of heat transfer problems are generally based on the energy balance and the estimated

heat transfer rate. Heat transfer will occur when there is a temperature difference between two

objects. The heat will move from a high-temperature object to a lower temperature object. Heat

can move in 3 ways ie conduction, convection, and radiation. In the event of conduction, heat

moves along the path without the need of the medium to move. The heat moves from one particle

to another in the medium. Convection events occur when heat transfer is carried by fluid flow.

Thermodynamically, convection is expressed as the enthalpy stream, not heat flow. In the event

of radiation, energy travels through electromagnetic waves.

There are several common heat exchangers used in industry. These heat exchangers include

double pipe, shell and tube, plate-frame, spiral, and lamella. The plate and frame type heat

exchanger was developed in the late 1950s. Many researches have been done on this type of heat

exchanger. Generally, water is used as the operating fluid.

In this lab, the fluid used is air. Air is used as an operating fluid in an effort to optimize the heat

carried by flue gas from a plant's operation. This practicum is also one of the more in-depth

review efforts on flue gas. The result of practicum expected to be correlation between Reynolds

number with Nusselt number.




HXG – 2016/PW 7

CHAPTER II

EXPERIMENT GOALS AND OBJECTIVES

I. Goals

The goal of this practicum is to:

1. Learn the phenomena of heat transfer through plate and frame heat exchanger practicum.

2. Make students be able to choose the best heat transfer configuration.

II. Objectives

In the end of this practicum, students are expected to:

1. Determine overall heat transfer coefficient for variations of flowrate, inlet temperature,

flow direction, and fluid placement.

2. Determine empiric heat transfer coefficient.

3. Obtain a configuration which gives the the best heat transfer coefficient.

4. Find correlation between Reynold and Nusselt Number.




HXG – 2016/PW 8

CHAPTER III

RANCANGAN PERCOBAAN

I. Equipment Layout

HE Plate and Frame

Valve by-pass

Valve aliran panas

Valve aliran dingin

Blower

Heater

Udara lingkungan

Udara by-pass

Udara dingin keluar

Udara panas masuk

Udara panas keluar

Udara dingin masuk

Figure 1. HXG equipment layout.

II. Supporting Equipments and Materials

a. Measurement Tools

1. Thermocouple

2. Wet test meter

3. Manometer

4. Laptop (software: Labview)

5. Stopwatch

b. Material

Air




HXG – 2016/PW 9

CHAPTER IV

WORKING PROCEDURE

I. Working Procedure

Procedure in conducting the experiment is shown by Figure 2..

Start

Calibration of hot/cold air

flowrate using wet-test meter

Determining value of

End

Experiment I using counter-

current plate with cold/hot

flowrate variation

Determination of heat transfer

characteristics (Q, U, h, Re, Nu)

Data processing and analysis

Experiment I using counter-

current plate with cold/hot

flowrate variation

Figure 2. Experiment procedure.




HXG – 2016/PW 10

II. Measurement Methods

The experimental parameters were obtained from thermocouples mounted on the inlet/outlet

stream of the hot and cold fluid. The measurement of experimental variables is obtained from

fluid flow rate measurement using calibrated flowmeter. Calibration is done by using wet-test

meter.

Observed parameters are:

1. Flue gas inlet temperature (Th,i)

2. Flue gas outlet temperature (Th,o)

3. Cold air inlet temperature (Tc,i)

4. Cold air outlet temperature (Tc,o)

5. Flue gas inlet wall temperature (Twh,i)

6. Flue gas outlet wall temperature (Twh,o)

7. Cold air inlet wall temperature (Twc,i)

8. Cold air outlet wall temperature (Twc,o)

Variables used in the experiment are flue gas flowrate and cold air flow rate.




HXG – 2016/PW 11

BIBLIOGRAPHY

Mc Cabe, W.L., Unit Operation of Chemical Engineering, 5rd

Edition, McGraw-Hill Book

Co., Singapore, 1993, pp. 309-369.

Brown, G.G., Unit Operatons, Charles E. Tutle Co., Tokyo, 1960, pp. 415-447.

Perry, R., Green, D.W., and Maloney, J.O., Perry’s Chemical Engineers’ Handbook, 6th

Edition, McGraw-Hill, Japan, 1984, Section 11 pp. 11-1 to 11-31




HXG – 2016/PW 12

APPENDIX A

RAW DATA TABLE

The data obtained from this experiment are divided into three steps:

6. Calibration data of flowrate

Table 1. Flowrate calibration data.

∆h (cm) V (L) t (s)

2. Determining τ value

Table 2. Data for determining τ value.

t (s) T (oC)

3. Main Experiment Data

Table 3. Main experiment data.

∆h,cold ∆h,hot Th,I (oC) Th,o (

oC) Tc,i (

oC) Tc,o (

oC) Twh,i (

oC) Twh,o (

oC) Twc,i (

oC) Twc,o (

oC)




HXG – 2016/PW 13

APPENDIX B

CALCULATION PROCEDURE

B.1 Heat Transfer Rate (Q)

The heat transfer rate of hot fluid and cold fluid is calculated using below formula.

𝑞ℎ𝑜𝑡 = 𝑚ℎ𝑜𝑡. 𝑐𝑝ℎ𝑜𝑡. (𝑇ℎ𝑜𝑡,𝑖𝑛 − 𝑇ℎ𝑜𝑡,𝑜𝑢𝑡)

𝑞𝑐𝑜𝑙𝑑 = 𝑚𝑐𝑜𝑙𝑑. 𝑐𝑝𝑐𝑜𝑙𝑑. (𝑇𝑐𝑜𝑙𝑑,𝑖𝑛 − 𝑇𝑐𝑜𝑙𝑑,𝑜𝑢𝑡)

B.2 Calculating qloss

Heat dissipated to surroundings is shown as qloss.

𝑞

−

𝑞

−

The value of thermal conductivity, thickness, and cross-sectional area of kaowool is obtained

from literature.

B.3. Calculating Heat Transfer Rate of Operation (q,operation)

qoperation for each fluid is shown below.

𝑞𝑜𝑝𝑒𝑟𝑎𝑠𝑖,ℎ𝑜𝑡 = 𝑞ℎ𝑜𝑡 − 𝑞𝑙𝑜𝑠𝑠

𝑞𝑜𝑝𝑒𝑟𝑎𝑠𝑖,𝑐𝑜𝑙𝑑 = 𝑞𝑐𝑜𝑙𝑑 − 𝑞𝑙𝑜𝑠𝑠

B.4. Calculating ΔTlmtd for Cross-Flow and Counter-Current Flow Heat Exchanger

The temperature difference used is called log mean temperature difference, which is

calculated using below formula:

Equation above can only be used for counter-current flow heat exchanger. Above equation can

be used for cross-flow type of heat exchanger by multiplying it with correction factor.

∆𝑇𝑙𝑚𝑡𝑑,𝑐𝑟𝑜𝑠𝑠𝑓𝑙𝑜𝑤 = ∆𝑇𝑙𝑚𝑡𝑑,𝑐𝑜𝑢𝑛𝑡𝑒𝑟𝑐𝑢𝑟𝑟𝑒𝑛𝑡. 𝐹 𝑜𝑟𝑒 𝑠𝑖




HXG – 2016/PW 14

To find the correction factor from above graph, the value of Z and ɳ need to be calculated

first using below formulas.

The correction factor is obtained from Figure 12.

Figure 3. Correction factor for ΔT for cross-flow type of heat exchanger (McCabe, 1993).

B.5 Calculating Overall Heat Transfer Coefficient (U)

Overall heat transfer coefficient can be calculated using two methods: empiric and theoretic.

Theoretic overall heat transfer coefficient is calculated using following formula:

x : plate wall thickness

k : thermal conductivity of material

hh : convective heat transfer coefficient of hot fluid

hc : convective heat transfer coefficient of cold fluid

Empiric overall heat transfer coefficient is determined using below formula:




HXG – 2016/PW 15

B.6 Determining Convective Heat Transfer Coefficient (h)

The convective heat transfer coefficient is determined by using following formula:

The temperature difference used in the calculation is called log mean temperature difference,

which stands for the difference between the temperature of fluid and temperature of heat

exchanger wall.

B.7 Calculating Nusselt Number and Reynold Number

The Reynold number is determined using following formula:

h : convective heat transfer coefficient

D : Plate equivalent diameter

k : fluid thermal conductivity

The Reynold number is determined using following formula:




HXG – 2016/PW 16

ρ : fluid density

v : fluid flowrate

µ : fluid viscosity

D : diameter

B.8 Determining the Correlation between Nusselt Number and Reynold Number

Mathematically, the goal of this experiment is to find the value of a and b in below equation:

𝑁𝑢 = 𝑎 𝑅𝑒𝑏

The values of constant a and b can be determined from the regression between ln Nusselt and

ln Reynold. From the experiment result, two plots were obtained for: 1) Nusselt number for

hot fluid to Reynolds number, 2) Nusselt number for cold fluid to Reynolds number.

B.9 Calculating the Efficiency of Heat Exchange

The degree of heat exchange is shown through heat transfer efficiency which is shown by the

formula below:




HXG – 2016/PW 17

APPENDIX C

SPECIFICATION AND LITERATURE DATA

I. Literature Data

Literature data needed for data processing in HXG practicum module are:

1. Fluid density as a function of temperature

2. Fluid heat capacity (Cp) as a function of temperature

3. Fluid viscosity as a function of temperature

4. Fluid conductivity as a function of temperature

5. Specification of heat exchanger shown by Table 4.

II. Equipment Specification (HXG)

Table 4. HXG equipment specification.

Unit Counter-current Cross-current Note

Jacket (kaowool)

Conductivity

k

W/m.K

0,029

0,029

cotton

Cross-sectional

area

A m2 0,1443 0,1439

Thickness

∆x

m

0,017

0,017

Plate

Conductivity

k

W/m.K

42

42

iron

43 43 steel, carbon 1%

Cross-sectional

area

A m2 0,0585 0,05846

Plate thickness

∆x

m

0,005

0,005

Pipe

Diameter

de

m

0,02804

0,02804




HXG – 2016/PW 18

JOB SAFETY ANALYSIS

No Materials Properties Countermeasures

1 Air

(79% N2, 21%

O2 )

Odorless

Gas

Colorless

Not toxic

Not hazardous

Melting point of

-216,2o C (10

psig)

Density of 1,2

kg/m3 (1 atm)

No specific

countermeasures needed.

Leakage of hot gas is

hazardous. If that

happens, quickly

identify point of leakage

and close the leakage.

Avoid direct contact

with body

Accidents that may happen Countermeasures

Short circuit connection due to electricity

contact with water

Try to cut the electrical connection on

equipments. If not possible, contact authorities.

Slip caused by water puddle from leakage

of hose/pipe connection.

Make sure all hose/pipe connections are

properly assembled to prevent leakage. Clean

water spill immediately.

Valve or handle broken. Make sure the direction of rotation of

connection is correct. Try to open valve slowly

to prevent breaking valve. If broken, change the

valve with the new one or contact authorities.

Safety gear

Gloves Labcoat Mask Goggle

Asisten Pembimbing Koordinator Lab TK

GAS GAS HEAT EXCHANGER (HXG)

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