Energy Balance in Multi-injection Microstructured Reactors

1 Mass and Energy Balance in Multi-injection Microstructured Reactors 

The only difference is a sudden change in temperature and reaction mass at each injection point J, which can be described by using a Dirac pulse S z) and the Heaviside function ff (z). Reactant A2 contained in flow 2 is injected in deficit to reactant Ai into flow 1 before reaching the last point, where the stoichiometric balance is attained. It is assumed that the volume of the injected reactant is equal at each injection point and that it mixes instantaneously with the main stream. 

The third term of heat balance (Equation 5.54) is the heat added to the system because of the eventual temperature difference between the injected flow V2 and the main flow denoted as — T). The above equations can be solved using a simple ordinary differential equation solver for each interval between two injection points. In this case, the boundary conditions of the /th interval have to be adapted considering the reaction mass injected at point J and its temperature as well as the temperature and concentrations at the end of the interval j - 1. 

If instantaneous mixing and reactions are considered, the heat is produced at the injection point in the reactor. The heat evacuation time can be calculated by 

Integration of Equation 5.55 allows to determine the residence time between two injection points (tj), respectively, the distance (Lj) to cool the reaction mass from to (Equation 5.56). 

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