Energy Balance and Heat of Reaction

From the conservation of energy and assuming a steady-state condition  

ENERGY ENERGY ENERGY INPUT OUTPUT ACCUMULATION 

Consider a constant pressure, steady-state flow process with an inflow of reactant in section (1) and the outflow of the product in section (2) leaving the system boundary (i.e., a chemical reactor). 

During time 8t from t to t + St, the energy balance is expressed as 

Equation 6-10 is the macroscopic energy balance equation, in which potential and kinetic energy terms are neglected. From thermodynamics, the enthalpy per unit mass is expressed as 

Fig ure 6-1. Energy balanoe in ohemioal reaotors, where G = mass flow-rate u = internal energy per unit mass P = pressure p = fluid density m = mass of fluid in the system Q = rate at whioh heat is transferred to the system and = rate at whioh work is done on the surroundings. 

During time 6t from t to t -i- St, die energy balanee is expressed as 

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