The following is an excerpt from The Morning News, Wilmington, Delaware (August 3, 1977):...

The following is an excerpt from The Morning News, Wilmington, Delaware (August 3, 1977): “Investigators sift through the debris from blast in quest for the cause [that destroyed the new nitrous oxide plant]. A company spokesman said it appears more likely that the [fatal] blast was caused by another gas- ammonium nitrate—used to produce nitrous oxide.” An 83% (wt) ammonium nitrate and 17% water solution is fed at 200 °F to the CSTR operated at a temperature of about 510 °F. Molten ammonium nitrate decomposes directly to produce gaseous nitrous oxide and steam. It is believed that pressure flue- tuations were observed in the system and as a result the molten ammonium nitrate feed to the reactor may have been shut off approximately 4 min prior to the explosion, (a) Can you explain the cause of the blast? [Hint: See Problem P9-3b and Equation (8–75).] (b) If the feed rate to the reactor just before shutoff was 310 lbm of solution per hour, what was the exact temperature in the reactor just prior to shutdown? (c) How would you start up or shut down and control such a reaction? (d) What do you learn when you apply the runaway reaction criteria?

Assume that at the time the feed to the CSTR stopped, there were 500 lbm of ammonium nitrate in the reactor. The conversion in the reactor is believed to be virtually complete at about 99.99%.

Additional information (approximate but close to the real case):

where M is the mass of ammonium nitrate in the CSTR (lbm) and k is given by the relationship below.

The enthalpies of water and steam are

(e) Explore this problem and describe what you find. [For example, can you plot a form of R(T) versus G(T)1\ (f) Discuss what you believe to be the point of the problem. The idea for this problem originated from an article by Ben Horowitz.