Mechanical Engineering Lab: LPG Calorific Value Determination

This lab report details an experiment to determine the calorific value (CV) of Liquefied Petroleum Gas (LPG) using a Boys calorimeter. The report begins with an introduction to the concept of calorific value and its importance in thermodynamics, differentiating between Higher and Lower Calorific Values. The theoretical background includes the principles of the Boys calorimeter, explaining how the heat released during LPG combustion is used to raise the temperature of water. The experimental procedure outlines the setup, which involves measuring gas flow, water temperature changes, and condensate mass. Data collected includes gas pressure, initial and final gas meter readings, inlet and outlet temperatures of both gas and cooling water, and condensate mass. The results section presents calculations to determine the calorific value, followed by a discussion of the findings and a conclusion confirming the experiment's success. The report also includes relevant references.

OBJECTIVES
 To determine the Calorific Value of the LPG
 To determine the basic difference that is present in between the Lower calorific value and
Higher calorific value
INTRODUCTION
This lab report discusses about the different values that are considered important for developing
of the calculation process of thermodynamic values that are important in the calculation process.
This laboratory report is concerned with the amount of heat that is released in the process of
combustion.
It is highly important to differentiate in between the Higher calorific value and Lower calorific
value. Proper discussion regarding the Higher Heating Value is also performed in the process.
The standard measurement that will be used in the process of calculation is 25℃.
Theory
The main theory that is to be considered in the process is regarding the Boy’s calorimeter. The
apparatus is named after the Physicist whose name was Sir Charles Boys. This apparatus is
mainly used for performing accurate determination of the calorific value of the gases. Hence this
apparatus finds its place in the regular usage in the industry. The major principles that are
considered important for proper processing of the business process is that the heat that is
produced by the constant flow of the gas has been getting utilized in a manner that temperature
of the constant flow of the water have been raising. The calorific value of the process is
calculated with the help of the measurement of mass. It is noticed that the temperature of water

keeps on increasing through the calorimeter. This entire process is performed in manner that a
fixed gas is burnt.
The apparatus that are required in the process for completion of the experiment are namely the
Boy’s calorimeter, LPG cylinder, Beaker (Graduated), the capacity of the beaker needs to be
100cc and 2000 cc. Usage of the thermometers are also mad in the experiment. Another aspect
that is to be considered in the process of experiment is the Electronic thermometer.
Fig-1 Boy’s Calorimeter Apparatus
The procedure that is needed to be followed in completion of the experiment are as follows: -
 In the initial step the water is needed to be feed open. This section ensures the fact that
proper adjustment of the flow rate until the rate is nearly 1.5 ltrs in a minute takes place.
In this process the 2000 cc capacity graduated beaker is required for the measurement
purpose.

 In the very next stage the main aspect that is to be considered is turning the burner on and
proper adjustment of the gas pressure is made. It is ensured that blue flame is received.
The combustion process is regulated with the help of the regulator. This process is
continued until the flame turns grey blue color.
 In the process of checking the regulatory of the flame the main aspect that is considered
is that gas flow is adjusted.
 After this step the gas flow is measured and this is one of the most important step that is
to be taken for completion of the experiment.
 After this step, the temperature difference is measured. This have been one of the major
aspect that have been providing the result that have been received.
 After this process measurement of the barometric pressure is considered. This is have
been providing better understanding of the process. The temperature is measured as tR.
 After this step the gas meter reading is also considered. This have been one of the major
aspect that is to be considered.
 After this process, the gas metric value is considered. This section ensures the process
that the integer value of the gas volume is considered. Starting time of the records and the
initial gas meter is well measured.
 In the mean time it have been ensured that 100 cc graduated beaker have been present
and this has been procuring the fact that it is under the condense discharge tap along with

the 2000 cc graduated beaker. This process is performed under the cooling water
collection tap. After this process the temperature is recorded.
 After this process the main aspect that is considered is that the gas meter is indicated with
the help of the integer value. After this process the condensate beaker is removed and this
ensures that there will be stopping in collection of the cooling water.
 Weight as well as recording of the corresponding mass of the condensate and cooling
water will be measured. This section ensures that there will be better assessment of the
condensate and the cooling water that are collected in the beakers. Recording of the data
is performed and in case the data that are received are not satisfying regeneration and
collection of the data will be done.
 After collection of data, the entire process is needed to be repeated. This section includes
the fact that four sets of readings will be calculated.
 After this process, repeating of the experiment by altering the gas pressure will be made.
The expression that are calculated in terms of the thermo dynamical values includes the
following terminology, namely Kilojoules per Kilo mol of fuel, Joules per gram of fuel, BTU
lb
and lastly the Energy per unit volume of fuel
After proper calculation, the energy that is released is calculated as H=mCP ∆ T .
The units that are stated in the equation are as follows: Where, H = heat energy absorbed (in J),
ΔT = change in temperature (in °C),

m = mass of water (in g)
Cp = specific heat capacity (4.18 J/g°C for water).
The energy balance equation that is considered in the process is H= mw ×Cw × ∆ tw
V g
. In the
equation the values that are stated are namely the H = Calorific value of the gas (KJ⁄m^3 ),
m_w= Mass of water (Kg), C_w= Specific heat of water (4.1868 KJ/Kg K), ∆t_w= Temperature
difference of the water between inlet and outlet (K), Vg = Volume of gas (m3).
EXPERIMENTAL DATA / READINGS
The following readings were recorded during the experiment as tabulated in table-1,2&3
below:
TABLE-1
DATA FOR GAS
Parameter Unit Reading
Gas Pressure mbar 5
Initial Reading (Vgas1) dm3 5
Final Reading (Vgas2) dm3 17
Total Volume of Gas (V2-V1) dm3 12
Elapsed Time min. 2min, 11sec

Inlet Temperature (tgas, in) ℃ 20
Exhaust Temperature (tgas, out) ℃ 50
TABLE-2
DATA FOR COOLING WATER
Parameter Unit Reading
Volume collected (Vw) L 1
Inlet Temperature (tw, in) ℃ 22.18
Outlet Temperature (tw, out) ℃ 79.6
Elapsed time min 2min, 11sec
TABLE-3
DATA FOR CONDENSATE
Parameter Unit Reading
Mass of condensate, (mw) g 1000
Elapsed time min 2min, 11sec
RESULTS/CALCULATIONS
Calculation for Calorific Value:
Calorific Value is given by-
H= mw ×Cw × ∆ t w
V g

H = 1× 4.1868 ×(79.6−22.18)
12 ×0.001 = 20033.84 KJ
m3
DISCUSSIONS
As per the goal of the discussion, it can be stated that determination of the CV of LPG.
Comparison of the data collected have been other goal in the experimental process. From the
above tables, it can be stated energy content of the LPG have been 20033.84 KJ
m3
CONCLUSION
Calculation was performed in an accurate manner. This section ensures that error
reducing mechanism is used in the process. Proper data sets have been collected as well. The
experiment can be considered to be a success.
REFERENCES
 Michael J. Moran, H.N. (2006). Fundamentals of Engineering Thermodynamics. West
Sussex: John Wiley & Sons, Inc.
 https://slideplayer.com/slide/4894449/16/images/22/
BOYS+OR+JUNKERS+GAS+CALORIMETER.jpg
 http://www.ieicos.com/IEICOS-Boys-Gas-Calorimeter-Catalog-2011.pdf