EPT 201 Thermodynamics Laboratory Module

Experiment 2 : Marcet Boiler

EXPERIMENT 2

Marcet Boiler

1.  OBJECTIVE

2.  INTRODUCTION

3.  COMPONENT AND EQUIPMENT

4.  PROCEDURE

5.  RESULTS

6.  DISCUSSION / EVALUATION AND QUESTION

7.  CONCLUSION

EXPERIMENT 2

Marcet Boiler

1. OBJECTIVE

1.1  To obtain a relationship between the pressure and temperature of saturated steam, in equilibrium with water, at all pressure between atmospheric and 10 bar (150 lb/in2 ).

1.2  To compare between calculated values from experiment data to the data obtained from steam table for vfg and hfg .

2. INTRODUCTION

2.1 Background

The study of the laws that govern the conversion of energy from one from to another , the direction in which heat will flow , and the availability of energy to do work. It is based on the concept that in an isolated system anywhere in the universe there is a measurable quantity of energy called the internal energy (U) of the system. This is the total kinetic and potential energy of the atoms and molecules of the system of all kinds that can be transferred directly as heat; it therefore excludes chemical and nuclear energy. The value of U can only be change if the system ceases to be isolated. In this circumstances U can change by the transfer of mass to or from the system, the transfer of heat (Q) to or from the system, or by work (W) being done on or by the system.

Marcet Boiler has been developed for investigating the relationship between the pressure and temperature of saturated steam, in equilibrium with water, at all pressure between atmospheric pressure and 10 bar ( 150 lb/in2 ) . The measure value of the slope of the graph ( dT/dP )SAT obtained from the practical results can be compared with corresponding values calculated from the data in steam tables.

Clausius ( 1822-1888 ) the German Physicist and one of the founders of Thermodynamics was instrumental in deriving the relevant Clausius-Clapeyron relationship:

Therefore,

the value of vg is much larger than vf , then :

where :

Vf = specific volume of water

Vg = specific volume of steam

hf = enthalpy of water

hg = enthalpy of steam

hfg = enthalpy of evaporation

Useful conversion.

1 Pa = 1 N/m2

1 J = 1 N.m

1 bar = 105 Pa

1 bar = 102 kPa

1 K.m3 / kJ = 100 K / bar

K. m3 = K . m3 x J x 105 N/m2

kJ 103J N.m bar

1 K.m3 / kJ = 100 K / bar

3. COMPONENT AND EQUIPMENT

Figure 1: Marcet Boiler (Solteq HE 169)

A. Part Identifications List
1 / Bench / 7 / Pressure Gauge
2 / Panel / 8 / Pressure Relief valve
3 / Marcet Boiler Vessel / 9 / Temperature Sensor
4 / Temperature Indicating Controller / 10 / Hand Valve
5 / Pressure Indicator / 11 / Heater
6 / Pressure Transmitter
B. Specifications
1.  Pressure vessel ; 5 liter capacity made of stainless steel
2.  Pressure gauge ; 0 to 20 bar (Bourdon type)
3.  Thermometer ; Glass, 0 to 200˚C
4.  Transducers ; Temperature and Pressure
5.  Operating pressure ; Maximum 15 bar
6.  Electrical heater ; 2 kW, immersion type
7.  Temperature controller ; thermocouple / PT 100 input
8.  Safety ; Temperature controller , pressure relief valve
9.  Certification ; Tested at 30 bar , JKJ approved
10.  Electrical : 240AC/1-ph/50Hz
4. Procedure
No. / Experiment Procedure
1 / Open the hand valve. Then switch on the power supply.
2 / Wait and observe the steam released from the hand valve.
This is to assure there is no air/gas left in the boiler.
Danger: The steam is hot; DO NOT stay near to the hand valve.
3 / After steam is released about 1 minute, close and lock the hand valve and continue the heating process until the pressure gauge reaches the maximum reading of 10 bars.
4 / During heating process, pressure and temperature will increase. Take both the temperature readings started at 1 bar and continue the reading until 10 bar. Record your readings in table 1.
5 / Once pressure increase until 6 bars, switched ‘OFF’ the system.
END OF EXPERIMENT

Name :______

Matrix No. : ______

Date :______

5. Results

Data : Table 1

Atmosphere pressure : ______bar , Atmosphere temperature : ______(˚C)

Table 1

Experimental / Theory
Data (experiment) / Result / Data (steam table) / Result
Absolute Pressure,
P
(bar) / Temperature
Reading,
T
(0C) / Pressure difference, dP
(bar) / Temperature difference,
dT
(0C) / Measured slope
dT/dP
(K/bar) / Steam specific volume,vg
(m3/kg) / Enthalphy of evaporation
hfg
(kJ/kg) / Calculated slope
T. vg / hfg
(K/bar)
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0

1.  Plot a graph of Temperature (0C) v/s Absolute Pressure (bar). Label your graph.

2.  Show the dT and dP at data between pressure 3 bar to 3.5 bar in the graph. Measure the slope and compare to your theory result.

3.  Show all your calculation in separate sheets.

6. Discussion / Evaluation & question

6.1 Discuss experimental results. You may use below guidelines:

(Include a discussion on the result noting trends in measured data, and comparing measurements with theoretical predictions when possible. Include the physical interpretation of the results and graphs, the reasons on deviations of your findings from expected results, your recommendations on further experimentation for verifying your results, and your findings)

6.2 Why we need to release the air/gas from the equipment before the experiment?

6.3 Compare the experimental result with theoretical result. Give your comments.

6.4 Defined the relationship between the pressure and temperature?

6.5 If we increase the pressure, what will happen to the temperature?

7. Conclusion

Based on data and discussion, make your overall conclusion by referring to experiment objective.

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