Page 361 - Elements of Chemical Reaction Engineering Ebook

332 Multiple Reactions Chap. 6

ably active between temperatures of 330 K to about 430 K. The isothermal
reactions involved in the synthesis include
CO+2H, e
CH,OH
+
CO + H,O e H,
CO,
CH3OH CH,O+H,
The reactions are elementary and take place in the gas phase. The reaction is
to be carried out isothermally and as a first approximating pressure drop will
be neglected. The feed consists of A hydrogen gas, f carbon monoxide,
carbon dioxide, and steam. The total molar flow rate is 300 mol/s. The
entering pressure may be varied between 1 atm and 160 atm and the entering
temperature between 300 K and 400 K. Tubular (PFR) reactor volumes
between 0.1 m3 and 2 m3 are available for use.
(a) Determine the entering conditions of temperature and pressure and reac-
tor volume that will optimize the production of methanol. (Hint: First try
To = 330 at Po = 40 atm, then try To = 380 Po = 1 am.)
(b) Vary the ratios of the entering reactants to CO (i.e., OH2 and OHZO) to
maximize methanol production. How do your results compare with those
in part (a)? Describe what you find.

Additional information:
V = 40 dm3, Tis in kelvin. R = 1.987 cal/mol

13 1,667
exp[y. (;--..L]]
K, =

103.943
exp[ 7 - A]]
(;
K, =
.
;))I
* (A (s)
2
k, = 0.933 exp[2.5-[? - s-]

k,-= 0.636 exp ['".""" (3iO - - - f]],d,T;s -
-.

236-25, Oleic acid epoxide (E) is produced by the catalytic epoxidation of oleic acid
(OA) [J. Fotopoulos, C. Georgakis, and H. Stenger, Chern. Eng. Sci., 51, 1899
(1996)l. The raw materials are pure benzaldehyde (B) and oleic acid (OA).
Unfortunately, undesired products are also formed, including benzoic (BA)
and perbenzoic acids (PBA). The reaction sequence is

(1) O,+B k1 > PBA