PC-Class-4-Summary

Heat of Formation and Reaction: Professor MSubbu introduces the topic of heat of formation, heat of reaction, and heat of combustion, which form the basis for calculating heat of reaction. He outlines the problems they will cover, including heat of reaction at constant volume, heat transfer with single and multiple reactions, and ammonia formation. MSubbu mentions that additional problems are available in video lectures and textual courses, and announces that a test will be released soon. He also informs students about upcoming peer discussion sessions and changes to the class schedule, noting that they will finish process calculations before moving on to thermodynamics.

Calculating Heat of Reaction at Constant Volume: The discussion focuses on calculating the heat of reaction at constant volume for a gas phase reaction at 298 K. MSubbu explains that the difference between heat of reaction at constant pressure and constant volume is equal to the change in PV work, which can be expressed as RT multiplied by the sum of stoichiometric coefficients for gaseous components. He demonstrates how to calculate this difference using standard heat of formation data and the ideal gas equation, noting that for liquids and solids, there is typically no appreciable difference between constant pressure and constant volume heat of reaction.

Ammonia Oxidation Reactor Heat Transfer: The discussion focuses on solving a heat transfer problem for an ammonia oxidation reactor. MSubbu explains how to interpret the stoichiometry and heat of reaction data, identify the limiting reactant (ammonia), and calculate the extent of reaction. He then outlines the approach for energy balance, emphasizing the importance of using 298 K as the reference temperature. MSubbu guides through the process of determining the energy content of reactants and products, as well as the heat added by the reaction.

Ammonia Reaction Energy Balance Calculation: MSubbu explains the energy balance calculation for a chemical reaction involving ammonia. He clarifies that the heat of reaction is per mole of the limiting reactant, which is multiplied by the extent of reaction to get the total energy change. The energy balance equation includes the energy of the feed (zero), the energy added by the reaction, and the heat added or removed from the system (Q). MSubbu notes that the sign of Q indicates whether heat is added to or removed from the system, and he outlines how to calculate the energy content of the products using their specific heat capacities and the temperature difference from the reference temperature.

Solving Energy Balance for Ammonia Oxidation: The discussion focuses on solving energy balance problems for chemical reactions, particularly the oxidation of ammonia. MSubbu explains how to calculate the heat transfer in a reactor using given data on reactants, products, and their properties. He emphasizes the importance of using the correct specific heat capacity values for different temperature ranges and explains how to determine the extent of reactions using stoichiometric relationships. MSubbu also highlights the significance of choosing the appropriate reference temperature for energy balance calculations based on the available heat of formation data.

Ammonia Formation Energy Balance Problem: The discussion focuses on an energy balance problem for an adiabatic exothermic reaction involving the formation of ammonia. MSubbu explains that the feed, consisting of stoichiometric amounts of hydrogen and nitrogen, enters at 700 Kelvin. The heat of reaction is given at 700 Kelvin, and the adiabatic temperature rise should not exceed 100 Kelvin. The problem asks to determine the maximum allowable conversion under these conditions. MSubbu also mentions that the mean molar specific heat for the components is provided.

Ammonia Production - Fractional Conversion Calculation: The discussion focuses on solving a combined material and energy balance problem for the production of ammonia. Professor Subbu explains how to calculate the fractional conversion of nitrogen using the extent of reaction and energy balance equations. He sets up the equations using a reference temperature of 700 Kelvin and considers the heat of reaction. The solution reveals that the maximum allowable conversion is 12.2% to keep the product temperature at or below 800 Kelvin.

Isothermal Combustor With Two Reactions: The discussion focuses on solving a problem involving isothermal operation of a combustor with two reactions. MSubbu explains that the feed is a flue gas with added air passed through carbon, and the reactions produce carbon monoxide and carbon dioxide. He outlines the problem parameters, including the adiabatic nature of the combustor, the given heat of reaction, and the requirement to calculate the moles of CO2 per mole of O2 in the feed stream. MSubbu then guides through the process of setting up material and energy balances, considering the completion of reactions and solving for the required molar ratio of CO2 to O2 in the feed.

Energy Balance Test and Practice: MSubbu concludes the class on energy balance problems and discusses upcoming sessions. He announces a test covering both material and energy balance, which will be released tomorrow and due next Wednesday. MSubbu encourages students to practice problems from various sources, including video lecture courses, and emphasizes the importance of learning these concepts for future careers. He also mentions that the next class on Thursday will cover simpler problems from past GATE questions, and reminds students about tomorrow's peer discussion session.