Develop the PFD flow chart for the following process: Air is compressed and preheated, fresh and recycled methanol is pumped in and preheated, and these streams are mixed to be fed to the reactor. The feed mixture is 39 mol% methanol in air, which is greater than the upper flammability limit for methanol. The following two reactions take place in the reactor:

The reactor has a unique configuration, in which the silver catalyst is in the form of wires, suspended above a tube bank heat exchanger (the IC is inside the reactor). Because the reaction is highly exothermic, the heat generated in the adiabatic reactor must be removed quickly. The heat exchanger is similar to a shell and tube reboiler. In general, the liquid level is controlled in order to keep the heat exchanger always flooded. The reactor effluent enters an absorber where most of the remaining gases are purged in the gas outlet line. The methanol, formaldehyde and water enter a distillation column, where the methanol that comes out of the distillate is recycled at the beginning of the process; the bottom product is a mixture of formaldehyde and water containing a low percentage of methanol as an inhibitor of formaldehyde polymerization. The mixture is cooled and stored in a tank at a temperature between 35 and 45 C. The composition of formaldehyde in the tank is 37% by weight with less than 1% methanol.

+ O'I + OHOH +