Basic Principles and Calculations in Process Technology

Chapter 9. Energy Balances

9.1 Methodology

9.2 Simple Energy Balances

9.3 Simultaneous Material and Energy Balances

9.4 Simultaneous Balances with Chemical Reactions

9.5 Concluding Comments

Appendix 9A: Heat of Mixing

Problems

Energy balances add a new dimension to material balances. Just as matter cannot be created or destroyed in ordinary reactions, neither can energy. In addition, just as a component species’ accumulation of matter in a material balance equals the mass in, less the mass out, plus the mass generated, less the mass consumed, so too does the accumulation of energy. That energy accumulation or loss, which is a negative accumulation, results in a rise or a reduction of the system’s enthalpy until a steady state is reached whereby ...