Lab 14-process engineering lab 1

8/12/2019 Lab 14-process engineering lab 1

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1.0 ABSTRACT

Marcet boiler is a bench top unit designed to demonstrate the thermodynamics basic principal

of boiling phenomenon and this experiment was carried out to determine the relationship

between the pressure and the temperature of saturated steam in equilibrium.Besides that,this

experiment was also done to demonstrate the vapor pressure curve.The marcet boiler was

used for this experiment.When the pressure increases,the temperature also

increases.Therefore,the relationship of pressure and temperature is directly proportional.The

derived formula and the data were used to calculate the slope.The dT/dP measured was

compared with data in the steam table.Theoretically,the values measured should be almost the

same with the predicted values however there are small deviation which range from 0.50 % to

0.73% and this might be occurred due to the errors in reading accuracy,room temperature and

pressure.The result from this experiment is validating to the theory of the

experiment.Moreover,the experiment was successful conducted.


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2.0 INTRODUCTION

Marcet Boiler is one of the application that involving the studying the thermodynamic.The

study of thermodynamic related to the transfer of heat and work between a system and

surrounding.The process occurs causing the change in the properties of system.This experiment

showed the relationship between pressure and temperature of saturated steam in equilibrium

with water and data obtained will be compared with theoretical data in steam table.

This experiment is simple compared to other experiments.The recorded data for this

experiment is the temperature of steam that boiled starting at atmospheric pressure until

10kPa.The water is heated by a heater in an insulated pressure vessel(boiler) until reach the

boiling point.For every increment of 0.5 kPa in pressure,the temperature of steam was

recorded.As the pressure reached 10 kPa,the heater is switch off and the temperature for everydecrement of 0.5 kPa was also recorded.

The steam is an ideal gas which is the ideal gas always obey the equation of state that

relating the pressure,specific volume/density and absolute temperature with mass of molecules

and gas constant,R (Frederick A.Bettelheim and William Henry Brown,2007)

PV = nRT (Eq 1.0)

Where P = Pressure

V = volume

n = Moles of gas

R = ideal gas law constant

T = Temperature

By comparing the real gas with the ideal gas,the ideal gas at low temperature absolutely no

obeys the equation of state as it continues to undergo discontinues change of volume and

become liquids.A few changes have to be ceated from the original ideal gas equation of state in

order to allowing its application in the properties of real gas.

(p+ n2a/v

2) (V- nb) = nRT (Eq 2.0)

The Van der Waalss equation is the correction from the ideal gas equation.Another two

parameters are added into the ideal gas equation .The first is (n2a/v

2) for attractive


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intermolecular force that reduces the outside in order to gathering the gas together.The second

is (nb) to taking the finite molecular volume together in accounting as the real gas cannot be

compressed (Per Freiesleben Hansen,2009).


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7.0 RESULTS

Data(experimental) Result

Pressure,P(bar) Temperature,T (o

C) Measured Slope,

Absolute (abs) Increase

Decrease Average Average(K) (dT) (dP) (dT/dP)sat

1.0 198.06 100.3 100.3 100.30 373.45 - - -

1.5 297.09 109.7 111.2 110.45 383.6 10.15 99.03 0.102

2.0 396.12 119.0 120.2 119.60 392.75 9.15 99.03 0.092

2.5 495.15 126.4 127.8 127.10 400.25 7.50 99.03 0.076

3.0 594.18 132.7 134.1 133.40 406.15 5.90 99.03 0.060

3.5 693.21 138.2 139.6 138.90 412.05 5.90 99.03 0.060

4.0 792.24 143.0 144.4 143.70 416.85 4.80 99.03 0.048

4.5 891.27 147.4 148.7 148.05 421.20 4.35 99.03 0.044

5.0 990.30 151.4 152.7 152.05 425.20 4.00 99.03 0.040

5.5 1089.33 155.1 156.2 155.65 428.80 3.60 99.03 0.036

6.0 1188.36 158.5 159.6 159.05 432.20 3.40 99.03 0.034

6.5 1287.39 161.7 162.6 162.15 435.30 3.10 99.03 0.031

7.0 1386.42 164.7 165.7 165.2 438.35 3.05 99.03 0.031

7.5 1485.45 167.6 168.5 168.05 441.20 2.85 99.03 0.029

8.0 1584.48 170.3 171.3 170.80 443.95 2.75 99.03 0.028

8.5 1683.51 172.8 173.9 173.35 446.50 2.55 99.03 0.026

9.0 1782.54 175.3 176.4 175.85 449.00 2.50 99.03 0.025

9.5 1881.57 177.6 178.9 178.25 451.40 2.40 99.03 0.024

10.0 1980.61 179.8 179.8 179.80 452.95 - - -


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Data(steam table) Result

Calculated slope Error of

Percentage

(%)

Absolute Steam

specific

volume,vg

(m3

/kg)

Enthalpy of

evaporation

hfg (kJ/kg)

TVfg hfg (TVfg / hfg)

1.0 1.6491 2258 156.9 2248.6 0.07 -

1.5 1.1594 2226 131.9 2228.5 0.06 0.70

2.0 0.8856 2202 162.9 2202.1 0.07 0.56

2.5 0.7187 2181 87.1 2181.0 0.04 0.69

3.0 0.6057 2163 82.6 2162.8 0.04 0.67

3.5 0.5242 2148 72.2 2147.2 0.03 0.73

4.0 0.4623 2133 66.6 2114.1 0.03 0.67

4.5 0.4139 2120 61.0 2119.3 0.03 0.63

5.0 0.3748 2108 56.7 2107.0 0.03 0.57

5.5 0.3426 2097 52.6 2094.0 0.03 0.50

6.0 0.3156 2086 49.8 2084.6 0.02 0.67

6.5 0.2926 2076 47.2 2074.3 0.02 0.67

7.0 0.2728 2066 44.7 2065.2 0.02 0.67

7.5 0.2555 2056 42.7 2055.4 0.02 0.67

8.0 0.3156 2048 40.8 2045.9 0.02 0.67

8.5 0.2269 2038 39.0 2036.8 0.02 0.60

9.0 0.2149 2031 37.4 2028.7 0.02 0.60


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9.5 0.2041 2022 36.0 2020.3 0.02 0.50

10.0 0.1944 2015 34.9 2014.0 0.02 -


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12.0 REFERENCES

1. Frederick A.Bettelheim,William Henry Brown:Introduction to General,Organic andBiochemistry;Cengage Learning,Eight Edition;2007;Chapter 6;Gases,Liquids and

Solid;page 167

2. Per Freiesleben Hansen : The Science of Construction Materials;Springer;2009;Chapter1:System of Matter

3. Onkar Singh:Applied Thermodynamics;New Age International;Second Edition;1 January2006;Chapter 6;Availability and General Thermodynamics Relations;page 202

Lab 14-process engineering lab 1

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