Principles of Chemical Engineering Processes

Transcription

1 Principles of Chemical Engineering Processes MATERIAL AND ENERGY BALANCES SECOND EDITION NAYEF GHASEM REDHOUANE HENDA CRC Press is an imprint of the Taylor & Francis Croup, an Informa business

2 Contents Preface Acknowledgments Authors of Units xix Systems Conversion Factors xi xv xvii xxi 1. Introduction 1 Learning Objectives Definitions of Chemical Engineering Sets of Units and Unit Conversion Conversion of Units Temperature Measurement Temperature Conversion Significant Figures Multiplication, Division, Addition, and Subtraction of Significant Numbers Dimensional Homogeneity Dimensionless Quantities Process and Process Variables Process Flow Sheet Process Unit Process Streams Density, Mass, and Volume Mass and Volumetric Flow Rates Moles and Molecular Weight Compositions of Streams Mass Fraction and Mole Fraction Concentration Pressure Measurement Types of Pressures Standard Temperature and Pressure Pressure-Sensing Devices Process Classification and Material Balance Material and Energy Balances 38 Homework Problems 39 References 42 v

3 vi Contents 2. Process Units and Degrees of Freedom Analysis 43 Learning Objectives Process Units: Basic Functions Divider (Splitter) Mixer (Blender) Dryer (Direct Heating) Filter Distillation Column Multieffeet Evaporator Dehumidification Humidifier Leaching and Extraction Absorber (Stripper) Partial Condenser and Flash Separator Flash Separator Crystallizer Reactors Batch Reactor PFRs and PBRs CSTR and Fluidized Bed Reactor Process Flow Diagram Labeling a PFD Degrees of Freedom Analysis Possible Outcomes of DFA Independent Equations MultiunitPFD DFA, Multiunit Process 68 Homework Problems 71 References Material Balance on Single-Unit Process 75 Learning Objectives Introduction to Material Balance Material Balance Fundamentals Mass Balance on Steady-State Processes Stream Specification Basis for Calculation Procedure for Solving Material Balance Problems 83 Homework Problems 100 References Multiunit Process Calculations 105 Learning Objectives Multiunit Process Degrees of Freedom Analysis 106

4 Contents vii 4.3 Recycle, Bypass, Purge, and Makeup Recycle Bypass Purge Makeup 110 Homework Problems 132 References Material Balances on Reactive Systems 137 Learning Objectives Stoichiometry Basics Stoichiometric Equation Stoichiometric Coefficients Stoichiometric Ratio Limiting Reactant Excess Reactants Fractional Conversion General Material Balance Differential Balance Integral Balance Formulation Approaches of Mass Balance Extent of Reaction Method for a Single Reaction Element or Atomic Balance Method Molecular or Component Balance Approach Extent of Reaction and Multiple Reactions 157 Reactions Molecular Species Approach for Multiple 5.8 Degrees of Freedom Analysis for Reactive Processes Chemical Equilibrium Combustion Reactions Theoretical and Excess Air 172 Homework Problems 179 References Multiple-Unit Systems Involving Reaction, Recycle, and Purge 183 Learning Objectives Multiple-Unit Process Flowcharts Flow Sheet for Reaction with Recycle Reaction with Product Splitter and Recycle Reaction with Recycle and Purge Degrees of Freedom Analysis for Reactive Multiple-Unit Processes Reaction and Multiple-Unit Steady-State Processes 192 Homework Problems 208 References 214

5 viii Contents 7. Single- and Multiphase Systems 215 Learning Objectives Single-Phase Systems Liquid and Solid Densities Ideal Gas Equation of State Gas Density Real Gas Relationships Compressibility Factor (z) Virial Equation of State van der Waals Equation of State Soave-Redlich-Kwong Equation of State Kay's Mixing Rules Multiphase Systems Phase Diagram Vapor-Liquid Equilibrium Curve Vapor Pressure Estimation Clapeyron Equation Clausius-Clapeyron Equation Cox Chart Antoine Equation Partial Pressure Dalton's Law of Partial Pressures Raoult's Law for a Single Condensable Species Gibbs' Phase Rule Bubble Point, Dew Point, and Critical Point 242 Homework Problems 244 References Energy and Energy Balances 247 Learning Objectives Energy Balance for Closed and Open Systems Forms of Energy: The First Law of Thermodynamics Energy Balance for a Closed System Kinetic Energy Potential Energy Energy Balance for an Open System Steam Turbine Heaters and Coolers Compressors Mechanical Energy Balance Bernoulli's Equation Enthalpy Calculations Enthalpy Change as a Result of Temperature Constant Heat Capacity 271

6 Contents ix 8.5 Enthalpy Calculations with Phase Changes Energy Balance for Open Systems with Multiple Inputs and Multiple Outputs Enthalpy Change because of Mixing Energy Balance for Bioprocesses Psychrometric Chart Summary 293 Homework Problems 293 References Energy Balance with Reaction 299 Learning Objectives Heat of Reaction Heats of Formation and Heat of Combustion Extent of Reaction Reactions in Closed Processes Energy Balance for Reactive Processes Heat of Reaction Method Heat of Formation or Element Balance Method Simultaneous Material and Energy Balances Unknown Process Exit Temperature Combustion Processes Energy Balance in Bioprocesses Energy Balance in Membrane Reactors Summary 338 Homework Problems 339 References Simultaneous Material and Energy Balances 343 Learning Objectives Material Balances Conversion Yield Selectivity Extent of Reaction ( ) Energy Balances Heat of Reaction Method Heat of Formation Method Concept of Atomic Balances Mathematical Formulation of the Atomic Balance Degrees of Freedom Analysis for the Atomic Balance Implementing Recycle on the Separation Process 349 Homework Problems 375 References 381

7 x Contents Balances Unsteady-State Material and Energy Learning Objectives Unsteady-State Material Balance Unsteady-State Energy Balance 394 Homework Problems 405 References 406 Appendix 407 Index 437