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Unformatted text preview: Lesson 9 Methods and Strategies for Material Balance Calculations
In this lesson we will examine three strategies and methods for carrying out material balances on reactive processes
• • • Balances on atomic species Balances on molecular species Extent of reaction Reading
Chapter 4, section 4.7 in the text Elementary Principles of Chemical Processes, 3rdedition, Material Balance Procedures for Processes That Include Chemical Reaction
1. Write the balanced stoichiometric equation for the chemical reaction. The balanced equation indicates how the reactants combine to produce the reaction products. 2. Choose a basis for your calculation. You will generally choose a molar flow rate of one of the reactants or one of the products as your basis. If a basis is not provided, choose one yourself. 3. Draw a flowchart for the process. You will use the flowchart to identify and organize the information that you are given about the process. Label the streams with flow rates and composition, and also note any other information given. Once you have organized all of the information that you are provided, you are ready to write and solve the material balances. There are three different approaches that you can use: i) atomic balances ii) molecular balances iii) extent of reaction. The example illustrating these preliminary stepsAcetylene (C2H2) is produced by reacting methane (CH4) with oxygen in a continuous, steady state reactor. Other products of the reaction include hydrogen (H2) and carbon monoxide (CO). 20.0% excess oxygen is fed to the reactor, and the fractional conversion of the limiting reactant is 0.850. Calculate the composition of the output stream from the reactor. Solution i) Material balances on Atomic Species ii) Material balances on Molecular Species iii) Material Balances using the Extent of Reaction Summary and Preview
Material Balance on Processes that Include Chemical Reaction: Methods and Strategies for Material Balance Calculations ...
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