• Hanoi University of Mining and Geology

• ECH 158A

CHE655 – Plant Design Project #2 Summer 2014 DESIGN OF A CUMENE PRODUCTION PROCESS (Courtesy of the Department of Chemical Engineering at West Virginia University) Introduction Cumene (isopropyl benzene) is produced by reacting propylene and benzene over an acid catalyst. Cumene may be used to increase the octane in gasoline, but its primary use is as a feedstock for manufacturing phenol and acetone. The plant where you are employed has been buying cumene to produce phenol. Management is considering manufacturing cumene rather than purchasing it to increase profits. Someone has made a preliminary sketch for such a process and has submitted to the engineering department for consideration. Your group is assigned the problem of evaluating the sketch and recommending improvements in the preliminary design. Note that optimization is NOT required in this design project. Process Description Figure 1 is a preliminary process flow diagram (PFD) for the cumene production process. The raw materials are benzene and propylene. The propylene feed contains 5 wt% propane as an impurity. It is a saturated liquid at 25°C. The benzene feed, which may be considered pure, is liquid at 1 atm and 25°C. Both feeds are pumped to about 3000 kPa by pumps P-201 and P202, are then vaporized and superheated to 350°C in a fired heater (H-201). The fired heater outlet stream is sent to a packed bed reactor (R-201) in which cumene is formed as a desired product and p-diisopropyl benzene (PDIB) as an undesired product. The reactor effluent is sent to a flash unit (V-201) in which light gases (mostly propane and propylene, some benzene, cumene and PDIB) are separated as vapor in Stream 9. Stream 10, containing mostly cumene and benzene, is sent to a distillation column (T-201) to separate benzene for recycle from cumene product. The desired cumene production rate is 100,000 metric tons/yr. Process Details Feed Streams Stream 1: benzene, pure liquid, 25°C and 1 atm Stream 2: propy