Ethyleneoxide, propyleneoxide and epoxybutene can be produced in a cooled tubular reactor. This requires partial oxidation of ethylene, propylene and butadiene respectively. The complete oxidation of the reactants to CO₂ and H₂O is an undesired side reaction.

The kinetics can be simplified to:

    desired)  a A + b₁ B --> p P + p dH_P (R₁ = A₀₁ exp(-E_a1/RT) c_A^a1 c_B^b1)
undesired)  a A + b₂ B --> x X + x dH_X (R₂ = A₀₂ exp(-E_a2/RT) c_A^a2 c_B^b2)

Both gasphase reactions are (strongly) exothermic. For the design of an optimal and safe reactor (no runaway) it's necessary to be able to simulate both concentration and temperature profiles. Therefore a Pascal program was written to solve four mass balances (plug flow with axial dispersion) and an integrated heat balance simultaneously. The program can calculate stationary as well as instationary profiles and it can also be used to perform runaway analysis.

An example of a stationary profile is given in the figure.