 Myself Dr. Nitin Gramopadhyay working as assistant professor in Department of Humanities and Basic Sciences. Today we are going to learn a topic fuel and a particular beat from that topic that is determination of calorific value of a given sample of fuel. This is the learning outcome for today's session. At the end of this session students will be able to describe determination of calorific value of fuel by using Boy's calorimeter method. This is the content we are going to learn. First we will learn the definition of calorific value of fuel, then we will see the diagram of Boy's calorimeter, then construction and working of Boy's calorimeter, observations of the experiment and finally, we will learn how to derive the equations to calculate higher calorific value and lower calorific value of a given sample of fuel that is HCV and LCV equations. Now, as the today's beat is related with determination of calorific value of a fuel. So, first we will learn what do mean by calorific value of a fuel. It is the capacity of a fuel sample to evolve the heat, therefore calorific value of a fuel is the total quantity of heat liberated when a unit mass or volume of the fuel is burned completely. So, what is calorific value? It is nothing but the total amount of the heat evolved by burning a unit mass or volume of a fuel. We have three types of fuels such as solid, liquid and gas. Solid fuel possesses lower calorific value, liquid fuel possesses moderate calorific value and gases fuel possesses higher calorific value. Now, calorific value of a fuel sample can be determined by the following methods. For solid and non-volatile type of fuel, bomb calorimeter experiment is used and for gaseous and volatile type of fuel, Boyd's calorimeter experiment is used. Whereas, for all types of fuel we can find out the calorific value by using Duelong's formula which is also called as theoretical determination. But the Duelong's formula we can use only when we know the composition of the fuel. So, we will come to our beat that is Boyd's calorimeter experiment. First we will see the diagram of Boyd's calorimeter. The apparatus is used to find out the calorific value of gaseous as well as volatile type of liquid fuels. The apparatus consists of the suitable gas burner in which the known volume of gas at known pressure can be burned at uniform rate. On the burner there is a combustion chamber which has a copper tubing coil inside as well as the outside. So, this is the combustion chamber, this is the burner and this is having the pressure regulator through which we can adjust the flow of the gas and when gas undergoes the combustion process, it evolve the combustion products which are accumulating inside the combustion chamber. Water at constant rate is passed through the coil. Water enters from the top of the outer coil. See here the first water moves from the top of the combustion chamber which is also called as the inlet water which goes down from the inner as well as outer coils and finally it exits from this vane and which is known as the outlet water. The thermometer T1 and T2 gives the temperature of inlet water and outlet water respectively. During the process of combustion when we circulate the water, it flows down and up through the coil the flow of the water takes away practically all heat of the combustion and as a result of that the combustion product get condensed and the steam which is formed during the combustion gets condensed as condensed steam which can be collected at the bottom of the tray, the whole assembly is properly enclosed in a insulating chamber to avoid the loss of heat by radiation. Now we will see how it works. First the circulation of water and burning of gases fuel are continued at constant rates for about 15 minutes for initial warming up period. The rates of fuel burning and water circulation are controlled so that the exit water leaves the apparatus nearly at atmospheric pressure. When the steady conditions are established then the readings are taken simultaneously. Now here I would like to ask you one question, Boyce calorimeter is used for determination of calorific value of option A solid fuel, option B non-volatile liquid fuel, option C gases fuel and option D both B and C. For a moment and the correct answer is option C gases fuel. Now these are the observations of the experiment. The first observation is volume of gases fuel burnt at standard temperature and pressure that is denoted as V meter cube. So we are measuring how much volume of the gas we are allowing for going combustion process and that is denoted by in meter cube V in meter cube. Then second is the weight of water used for cooling. So if you remember the diagram the water enters from a inlet vent which is circulating through the combustion chamber just to condense the products of combustion and therefore the second observation is that how much water we require to do the condensation of all the combustion product and that is denoted by the W gram that is weight of water used for cooling W gram. Then the initial temperature of water which is also known as the inlet temperature of water that is T 1 degree centigrade and the second that is final temperature of water which is also known as outlet water temperature that is T 2 degree centigrade and H C V of the fuel is nothing but L calorie per meter cube. Now we will see the calculations heat liberated is equal to L V because heat liberated is a product of the capacity of that fuel to supply the heat multiplied by its quantity. So L is a calorific value H C V and V is a volume so the product is nothing but the heat liberated and heat absorbed is equal to W into bracket T 2 minus T 1 degree centigrade. So therefore what happens heat liberated is always equal to heat absorbed and therefore L V is equal to W into bracket T 2 minus T 1 degree centigrade because heat liberated is always equal to heat absorbed. Now I will replace L with H C V here we can see that key H C V is equal to W into bracket T 2 minus T 1 degree centigrade divided by V where W is mass of water used for cooling T 2 is temperature of outlet water T 1 is temperature of inlet water and V is volume of gas burned in meter cube. So this is about H C V. Now we will see how to calculate the L C V. L C V is nothing but the lower calorific value which is also known as a net calorific value and how it is determined? It is determined by using this equation that is L C V is equal to H C V minus M multiplied by 587 divided by V where M is mass of steam condensed. So if you remember the diagram and the working of the experiment what is the main objective of the experiment we are allowing the fuel that should undergo the process of combustion and as a result of that whatever the combustion products are forming these are condensed by circulating the water through the combustion chamber. And therefore that is collected as that is steam at the bottom and that is denoted by small m that is small m is equal to mass of steam condensed. So all that slides are prepared by using a textbook of engineering chemistry written by Jain and Jain. Thank you.