Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-III-27model of plug flow reactor. The final model includes mass and energy balance, kineticdescription, description of hydrodynamics and changing of physical properties.The values of reactor temperature and ethylene oxide conversion were obtained by thenumerical integration of the model. Molar ratio fatty amine:ethylene oxide was 1:2, heatcarrier temperature 100 °C (boiling water), initial temperature of the reaction mixture 100 °C.The integration was run up to 99% conversion degree. Results are listed in Table 1. Themaximum reactor temperature is limited by the product quality requirements (at hightemperatures the product becomes coloured). It is clearly seen that in the framework of themodel the range of reactor diameters when the reaction temperature does not exceed 480 K.Model predicts severe constrains in the choice of diameter and length of reactor tubes. Theacceptable range of tube diameter is 0.032-0.04 m and length 50-100 m. The sensitivity of thetemperature profile to the variation of parameters depends on their starting set. In our case themodel stability is increased with decreasing the pipe diameter and molar ratio ethylene oxidefattyamine. The stability is also increased with growth of the heat carrier temperature andreactants' feed linear rate. The model is most sensitive to the variations in heat carriertemperature. Under certain conditions the change of heat carrier temperature on 1 °C couldresult in great variations in the reactor temperature (up to 100 °C). The analysis of the modelbehaviour with the following constraints: heat carrier temperature variation ±5 °C and reactortemperature variation ±50 °C revealed that at pipe diameter 0.045 m the model sensitivityexceeds the acceptable limit of 10°C/1°C. The results demonstrated that when all ethyleneoxide is fed at the reactor inlet the acceptable range of process parameters is very narrow.Table 1Reactor temperatures ad different pipe diametersd(m) w (m/min) Reactor length (m) T-max (K)0.019 13.9 300 3900.032 8.25 100 4700.04 6.6 50 4800.049 5.4 35 5530.068 3.9 30 6070.079 3.33 27 6170.1 2.65 15 6200.125 2.10 10 6370.15 1.8 8 650ConclusionsThe model of the plug flow reactor for amine ethoxylation describing adequatelyexperimental data was built. It was shown how this model can be used to predict theperformance of a real reactor, i.e. the product distribution and the temperature profile.354