Chapter 9, Problem 9.30P

A gas mixture containing 85 mole% methane and the balance oxygen is to be charged into an evacuated well-insulated 20-liter reaction vessel at 25°C and 200 kPa. An electrical coil in the reactor, which delivers heat at a rate of 100 watts, will be turned on for 85 seconds and then turned off. Formaldehyde will be produced in the reaction

   $C{H}_4+O_2\to HCHO+H_{2}O$

The reaction products will be cooled and discharged from the reactor.

1. Calculate the maximum pressure that the reactor is likely to have to withstand, assuming that there are no side reactions. If you were ordering the reactor, why would you specify an even greater pressure in your order? (Give several reasons.)
2. Why would heat be added to the feed mixture rather than running the reactor adiabatically?
3. Suppose the reaction is run as planned, the reaction products are analyzed chromatographically. and some CO₂is found. Where did it come from? If you had taken it into account, would your calculated pressure in Part (a) have been larger, smaller, or can’t you tell without doing the detailed calculations?