Runaway Reaction

1085 Words5 Pages
Summary The principal objective of this experiment was to observe a runaway reaction with the use of a calorimeter. Using the Advanced Reaction System Screening Tool (ARSST) as our calorimeter we observed the reaction of methanol + acetic anhydride to form acetic acid and methyl acetate. The electrical heating rate (Te) of 2.0048 ◦C/min was maintained constant up to the temperature where the self-heating rate temperature (Ts) of 130.68 ◦C was detected at which time the calorimeter switches to an adiabatic state. At this adiabatic state the heat of reaction, activation energy, and appropriate vent sizing were calculated. Characterizing these attributes on a small scale aids in the design of control systems to remove heat (prevent runaway), as well as in the design of safety relief systems to protect from the effects of high pressure. Upon completion of the ARRST lab we calculated values of -832.88 J/mol for heat of reaction, 47.256 J/mol*K for activation energy, and a vent sizing area of 0.19269 m2. Results and Discussion Overall, the experiment proceeded as expected with one…show more content…
Graphical representation of self-heating rate vs. temperature. From Figure 2, the tempering temperature was determined to be 135.62 ◦C. By interpolating the Tset data provided, the Tset was determined to be 130.68 ◦C. Using these values and the equation, , the vent area was calculated to be 0.19269 m2. The data from the experiment indicates a deviation from the trend 27 minutes into the reaction, where a sharp rise in temperature takes place. During post-experiment inspection of the equipment, it was noted that the stir bar was found in the insulation of the ARSST, and not in the cell where it belonged. Having an unevenly mixed liquid could lead to pockets of fluid that are different temperatures than the rest of the mixture. If one of these, pockets were present in the region where the thermocouple was placed, a higher temperature reading could be produced.

More about Runaway Reaction

Open Document