Marcet Boiler

Student Name :- Kayfe Sayfadeen Saber

Class :- Second Stage - A

Course Title :- Laboratories II – Thermodynamic Lab

Department :- Mechanical & Mechatronic . Dep

College of Engineering

Salahaddin University – Erbil

Academic Year 2019 – 2020

1
-: ABSTRACT
Marcet Boiler is a bench top unit designed for the demonstration of the basic
principalof boiling phenomenon to study the relationship between the pressure
and temperature ofsaturated steam in equilibrium with water. This experiment was
also conducted to demonstratethe vapour pressure curve. Water at room
temperature was boiled until 185.0 °C and everychanges of pressure, the
temperature was recorded until 10.0 bar. Air was removed first toavoid any of
inaccuracy. After the heater was turned off and being cooled, the
temperaturewas recorded again until the steam pressure reached atmospheric
.pressure

The reading of increase and decrease in temperature was being calculated

to findtemperature at average. Average temperature at first reading is 106.15 °C
and increase until184.60 °C with 29 readings. The graph also shows that the curve
of pressure and temperatureare directly proportional as the temperature increase
with pressure. The graph of absolutepressure against dT/dP (measured slope)
was slightly deviate compared to absolute pressureagainst Tvg/hfg(calculated
slope). This occurred maybe because of a few errors during theexperiment was
conducted. Steam was allowed to come out from the vent valve for about
30seconds before the valve was closed is the main procedure. Air maybe not
completely flowedout from the valve so the reading was not being constantly
increased. Besides that, maybetemperature was taken while the pressure still not
.stable

2
 TABLE OF CONTENT
ABSTRACT :- ………………………………………………… 2

TABLE OF CONTENT ………………………………………..3

Introduction :- ………………………………………………….4

What is a boiler? ……………………………………………… 4

marcet boiler :- …………………………………………………5

Theory :- ……………………………………………………….5

How does a marcet boiler work :- …………………………….7

metal is used to make boiler :- ………………………………...7

CONCLUSION :- ……………………………………………..7

Parts of machine :- …………………………………………….8

Reference ………………………………………………………9

3
-: Introduction
Thermodynamics study about the interchange of heat and work between a systemand
the surroundings which occurs when the system undergoes a process.
Thermodynamics also concerned about the changes in the properties of fluid. Most
thermodynamics substances such as gases and vapours are often referred as P-V-T
substances. An ideal gas obey the equation of states that relates the pressure, the
specific volume or density, and absolute temperature with mass of molecule and the
gas constant, R. However, real gas does not absolutely obey the equation of state. A
few modifications on the ideal gas equation of state allow its application in the
properties of real gas. When energy is added within water, the increasing of activities
among the molecules caused the increase in the number of molecules escape from a
surface until the equilibrium sate is reached. The state of equilibrium depends on the
pressure between the water surface and steam. The lower the pressure, the easier the
molecules leaving the water surface and thus less energy is required to achieve the
state of equilibrium (boiling point). The temperature where equilibrium occurs at a
given pressure level is called saturated temperature. The pressure where equilibrium
occurs at a given temperature is called saturated pressure. Marcet boiler is used to
investigate the relationship between the pressure and the temperature of saturated
steam in equilibrium with water at all temperature levels between the atmospheric
pressure and 10 bars. The measured value of slope of the graph (dT/dP) obtained
from the experiment results can be compared to the theoretical value determined
.through the calculation from the steam table

?What is a boiler
Boilers are defined as   “Boiler is a closed vessel in which water or other liquid is
heated, steam or vapor is generated, steam is super-heated, or any combination
thereof, under pressure or vacuum, for use external to itself, by the direct application
of energy from the combustion of fuels, from electricity or nuclear energy.

The boiler is a primary part of global heating system in power plants. ”  

 The boiler system functions with the heat distribution system, heat-emitting
system & control systems.

 Boiler is the main working component of thermal power plants

4
-: marcet boiler
The Marcet boiler is used to investigate the between pressure and temperature of
saturated steam, in equilibrium with water, at all pressures between atmospheric and
a 14bar An ideal gas can be characterized by three state variables: absolute pressure
(P), volume (V), and absolute temperature (T)

-: Theory
Marcet Boiler (Model:HE169) has been developed for investigating the relationship
between the pressure and temperature of saturated steam, in equilibrium with water,
at all pressures between atmospheric and 10 bar (abs) (150lb/in2 ). Thermodynamics
is a branch of physics, which deals with the energy, and work of a system.
Thermodynamics deals only with the large-scale response of a system that we can
observe and measure in experiments. Small-scale gas interactions are described by
the kinetic theory of gasses which is compliment to thermodynamics. An ideal gas
can be characterized by three state variables :- 1) Absolute Pressure (P) 2) Volume
(V) 3) Absolute Temperature (T) The relationship between them may be deduced
from kinetic theory and is called the Ideal Gas law. The ideal gas law was originally
-: determined empirically and is simply

:Where

P = Absolute pressure

V = Volume

N = Amount of Substance ( moles )

R = Ideal Gas Constant

T = Absolute pressure ( k )

If a gas behaves exactly as the ideal gas laws would predict it to behave in terms of
the volume, pressure, moles and temperature, then the gas is said to be an ideal gas.
On the other hand, the gas deviates from Ideal Gas behavior, then the gas is said to be
:acting like a , real gas

5
When the energy increases within water, the increasing of activities among the
molecules enables the increase in the number of molecule escape from the surface
until the equilibrium state is reached. The state of equilibrium depends on the
pressure between the water surface and steam. At lower pressure, the molecules
become easier leaving the water surface while less energy required in achieving the
state of equilibrium (boiling point). The temperature where the equilibrium occurs at
.a given pressure level is called saturated temperature

The measured 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-Clapeyron states

When the phase transition of a substance is between a gas phase and a condensed
phase (liquid or solid), and occurs at temperature much lower than the critical
temperature of that substance, the specific volume of the gas phase , Vg greatly
. exceeds that of the condensed phase Vc

Therefore, one may approximate at low temperature Dv , is like the equation above.
,Therefore

: In which

Vf = Specific volume of saturated liquid

Vg = Specific volume of saturated vapour

6
Hf = enthalpy of saturated liquid

Hg = enthaloy of saturated vapour

Hfg = latend heat of vaporization

-: How does a marcet boiler work

The Marcet boiler is used to investigate the between pressure and temperature of
saturated steam, in equilibrium with water, at all pressures between atmospheric and
a 14bar An ideal gas can be characterized by three state variables: absolute pressure
(P), volume (V), and absolute temperature (T)

-: metal is used to make boiler

Materials. The pressure vessel of a boiler is usually made of steel (or alloy steel), or
historically of wrought iron. Stainless steel, especially of the austenitic types, is not
. used in wetted parts of boilers due to corrosion and stress corrosion cracking

-: CONCLUSION
Marcet boiler is the device which we use to study the relation in between pressure
and temperature for a water at saturated liquid phase. As we did in the laboratory, we
started heating water with constant pressure until it reached boiling point. Then,
closing the valve which created a constant volume system. Forcing the pressure to
increase as the temperature rises. And thus studying the direct relation between
pressure and temperature for water at that point. We notice that it is essential to close
the valve as we reach boiling point to make sure we are now in a constant volume
process, otherwise pressure would have never increased. causing the experiment to be
useless. We also notice that we closed the valve exactly when we reached boiling
temperature (95 c at 0.9 bar pressure) and thus keeping water at saturated liquid
phase. After studying the results and plotting the diagram we find that the relation in
between pressure and temperature is directly proportional. The difference between
the theoretical values and the actual values is caused by errors with certain calculated
acceptable percentages. In this experiment, the relationship between pressure and
temperature is found to be directly proportional. When compared to the theoretical
slope, the experimental slope shows a small deviation between them because of
.certain errors

7
-: Parts of machine

1.Pressure Transducer

2. Pressure Indicator

Temperature Controller/Indicator .3

Control Panel .4

Bench .5

Bourdon Tube Pressure Gauge .6

Temperature Sensor .7

Pressure Relief Valve .8

Heater 5. Bench .9

Water Inlet Port & Valve .10

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Refrence
/https://www.coursehero.com/file/12682450/marcet-boiling

/http://www.thermodyneboilers.com/what-is-boiler

https://www.scribd.com/document/249274076/Discussion-and-Conclusion-for-
Marcet-Boilers

Marcet Boiler. Slideshare.net. Retrieved 7 Jan 2015 from )1

. http://www.slideshare.net/ShwanSarwan/marcet-boiler

Why there should not be air in the boiler. Answer.yahoo.com. Retrieved 7 Jan )2
2015 from https://answers.yahoo.com/question/index?
. qid=20111012064442AAfAPTF

Marcet Boiler Lab Report. Scribd.com. Retrieved 7 Jan 2015 from )3

. http://www.scribd.com/doc/51634867/Marcet-Boiler-Lab-Report#scribd

Yunus A. Cengal & Michael A. Boles, “Thermodynamics – An Engineering )4

.Approach”, 3 rd Edition, 4th Edition, McGraw Hill, 2002

Lab2E5 Marcet Boiler. Academia.edu. Retrieved 7 Jan 2015 from )5

. https://www.academia.edu/9474636/Lab2E5_Marcet_Boiler

Food Steamer. Wikipedia.org. Retrieved 7 Jan 2015 from )6

. http://en.wikipedia.org/wiki/Food_steamer

Food Steamers Introduction. allianceforwaterefficiency.org. Retrieved 7 Jan 2015 )7

. from http://www.allianceforwaterefficiency.org/1Column.aspx?id=642

Steam Engine. Wikipedia.org. Retrieved 7 Jan 2015 from )8

. http://en.wikipedia.org/wiki/Steam_engine#Boilers