 Today we are going to learn calculation of calorific value of a given sample of fuel from a topic fuel. This is the learning outcome for today's session. At the end of this session, students will be able to define the terms fuel, calorific value, higher calorific value, lower calorific value and apply the knowledge to calculate higher calorific value and lower calorific value by using a given data of fuel. This is the content of today's session. First we will see the definitions of few terms like fuel, calorific value, higher calorific value, lower calorific value and then we will see how to calculate HCV and LCV of a given sample of fuel by using the provided data. What are fuels? The material which essentially consists of carbon as a major ingredient which on burning in presence of air combines with atmospheric oxygen and evolve carbon dioxide along with heat that is known as a fuel. So fuels are a materials which are rich in carbon which on burning in presence of air combines with the atmospheric oxygen and evolve carbon dioxide along with heat. The fuel exist in the form of solid, liquid and gas state. Fuel is the material used as a source of energy for domestic, industrial, transportation, agricultural and different kinds of work. The same definition we have represented with the help of chemical reaction that is carbon plus O2 that is oxygen from the air when it combine it form the carbon dioxide by the evolution of heat and these materials are known as fuel materials. Now what is calorific value? It is the capacity of the fuel to supply heat when calorific value of an fuel sample. Therefore the amount of heat produced by burning a unit mass of fuel is known as calorific value of that fuel. Solid fuels are low in calorific value, liquid fuels are moderate in calorific value and gases fuels are more in calorific value. So why the last sentence we have put here because solids are low in carbon therefore they are low in calorific value. Fuse are moderate in carbon level therefore they possess the moderate calorific value and gases are reached in the carbon contained therefore gases fuels are more in calorific value. So fuel with high calorific value also emits low emissions which is good from the prospect of environmental conditions. So in short calorific value is the total amount of the heat liberated by burning a unit mass of the fuel. Now there are two terms one is HCV that is higher calorific value and second one is a LCV that is lower calorific value. Higher calorific value is also known as gross calorific value. It is the total amount of heat produced when unit mass or volume of the fuel has been burned completely and the products of combustion have been cooled to room temperature. Similarly all fuel contains small quantity of hydrogen and when calorific value of such fuel is determined experimentally the hydrogen present is converted into steam. If the products of combustion are condensed to room temperature then the latent heat of condensation of steam also gets included in the measurement of heat which is then called higher or gross calorific value. So in short HCV is a concept because in a fuel whatever the level of carbon is there because of that certain amount of the heat will get evolved. But also the fuel consists of trace amount of hydrogen then on combustion hydrogen gets converted to steam which is very difficult to condense practically but in experiment we can condense and if you add the heat because of steam into the heat because of carbon that total heat is called as gross calorific value that is known as HCV higher calorific value. Now what is lower calorific value? Lower calorific value is also known as net calorific value which is available for direct use. It is the net amount of heat produced when unit mass or volume of the fuel is burned completely and the products are permitted to escape. In case of HCV, HCV value is along with the products of combustion and LCV is when the products are permitted to escape into atmosphere because it is very difficult to condense practically. Therefore, net or lower calorific value is the amount of heat that is available for actual use. The water vapor and moisture are not condensed and escape as such along with hot combustion gases. Hence, a lesser amount of heat is available which is known as lower calorific value that is denoted as LCV. Here I would like to ask you one question. Liquid fuel consists of option A lower calorific value option B moderate calorific value option C higher calorific value and option D none of these. Think for a moment we will come with answer and the correct option is option B liquid fuel consists of moderate calorific value. So liquid fuels are moderate in calorific value, solids are low in calorific value and gases fuels are more in calorific value. Now we will see the numericals. This is the first numerical based on bomb calorimeter experiment. This is one of the method where we can use the sample of fuel, we can perform the experiment, we can record the observation and by using that observation we will calculate LCV and LCV. So what is the numerical? Following are the observations recorded during the bomb calorimeter experiment. Calculate LCV and LCV into bracket the percentage of hydrogen is given that is 6. First observation is X that is mass of coal sample taken for experiment that is 1.3 gram. Capital W that is water taken in copper calorimeter that is 1,700 gram. Small w that is water equivalent due to stirrer, thermometer etc that is 350 gram. Hydrogen temperature 9.8 degree centigrade, acid value correction 50 calorie, fuse wire correction 10 calorie, cooling correction 0.025 degree centigrade and latent heat top steam is 587 kilo calorie per kg. So this is the standard formula for HCV for bomb experiment. Capital W plus small w in one bracket into another bracket T2 minus T1 plus CC minus AC plus FC divided by X. So the capital W value is 1700 that is water taken in copper calorimeter. Small w value is 350 that is water equivalent due to stirrer, thermometer etc that is 350 we are kept in one bracket. Hydrogen temperature is nothing but the difference in between T21 and that is given 9.8 plus cooling correction is 0.025. Then acid value correction is 50 calorie plus fuse wire correction is 10 calorie and the amount of fuel sample is 1.3. So by putting all the values we get the answer that is 15447.11 calorie per gram that is HCV. Now what is the formula for LCV? LCV is equal to HCV minus 0.09 multiplied by percentage of hydrogen multiplied by latent heat top steam. So already we got the HCV the same value we are putting here that is 15447.11 minus 0.09 multiplied by 6 is a percentage of hydrogen and multiplied by 587 as a latent heat top steam. So by putting all the values we are getting the answer for LCV for this particular example is 15130.13 calorie per gram. Now this is the second type of numerical on Boyce calorimeter experiment. Following are the observations recorded during the Boyce calorimeter experiment calculate HCV and LCV. V that is volume of the gas burn is 1.2 meter cube, capital W that is mass of water used for cooling is equal to 27 kg, rise in temperature is equal to 9.8 degree centigrade, small m that is mass of steam condensed is equal to 0.021 kg, latent heat top steam is equal to 587 kilo calorie per kg. This is the formula for HCV for Boyce calorimeter. So HCV is equal to W into bracket T2 minus T1 divided by V. So what is W? That is mass of water used for cooling the combustion products that is 27 kg. So we are kept here 27. The rise in temperature that is a difference in between T2 and T1 two temperatures are there that is T1 is a temperature of inlet water, T2 is a temperature of outlet water and the rise in temperature is given 9.8 divided by V is volume of gas burn that is 1.2. By putting the value we are getting the answer for HCV that is 220.5 kilo calorie per meter cube. What about LCV for Boyce experiment? LCV is equal to HCV minus M upon V multiplied by latent heat of steam. So HCV already we get the answer the same answer we are putting here small m is nothing but the mass of steam condensed during the experiment that is 0.021 kg, V is 1.2 and latent heat of steam is 587. So by putting all the values the answer for LCV is 210.23 kilo calorie per meter cube. All this I have prepared by referring a textbook of engineering chemistry written by Jain and Jain. Thank you.