Online Calorimeter Sensor

If the boiling point changes very slowly or only slightly, in practice, the absolute rates of heat release by the reaction and by condensation are equal. 

A prerequisite for the optimum, model-supported control of a chemical process is a comprehensive knowledge of the state of the reaction mixture at all times during the process. As a rule, only a few of the variables representing the state can be directly measured. 

Modem system theory [43] offers mathematical methods, which—on the basis of these variables together with thermodynamics, chemical kinetics and a reactor model—enable the estimation of additional state variables (e.g. Kalman-Bucy filter, Luenberger observer). The more accurate the process model which is assumed as a base, and the more numerous and meaningful the starting measured variables are, the greater is the number and accuracy of the additional, estimated state variables. Consequently, variables which are usually available (e.g. temperature, pressure) should, if possible, be supplemented by further variables which are more meaningful. 

The rate of heat production in a tank reactor is generally determined by the thermal balance of the system. Experience has shown that, when drawing up a thermal balance for the reactor itself and its cooling jacket, both the stirrer power 

To find the thermal reaction power in an ideally mixed tank reactor, it is recommended to use an appropriately designed flow calorimeter placed as a sensor in a short, thermally insulated by-pass. To equalize the specific rates of heat production in the tank reactor and sensor, the latter must be designed in such a way that both the composition and the temperature of the reaction mixture in the sensor correspond to those in the tank reactor. 

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Upon returning to Drexel in the summer of 1997, the author worked with graduate student Hamid Shirazi to develop a quartz crystal microbalance/heat conduction calorimeter based on this mass/heat-flow sensor. The development, testing, and initial uses of the QCM/HCC are documented in Shirazi s PhD thesis, available online [51]. Shira performed die following experiments with this new technology ... 

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