A chemical engineering consultant for a large refinery complex has been asked to investigate the feasibility of manufacturing 1

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A chemical engineering consultant for a large refinery complex has been asked to investigate the feasibility of manufacturing 1.44 x lo-* kg/s of thiophane, an odorant made from a combination of tetrahydrofuran (THF) and hydragen sulfide.

The essential reaction is given below: .

CH,-CH,

I 1 +H,Sc-=

CH,-CH,

I I

"9 5H2

+ H,O

"HI 732

0 S

The process consists essentially of the following steps:

(al THF is vaporized and mixed with H,S in a ratio of 1.5 moles H,S to one mole of THF and reacted over an alumina catalyst at an average temperature of 672 K and 207 kPa.

(b) Reactor vapors are cooled to 300 K and phase separated.

(cl The noncondensable gases are removed and burned in a fum

(d) The caustic treated thiophane is then batch distilled in a packed tower and sent to storage before eventual shipment to commerical use.

(e) Recoverable THF is recycled back to the reactors from the batch column.

(fl The aqueous bottoms stream is stored for further processing in the plant.

(g) Carbon deposition on the catalyst is heavy (4 percent of THF feed) and

therefore provision for regeneration of the catalyst must be made.

Assist the consultant in analyzing this process with a complete flow sheet and material balance, assuming 85 percent operating factor, 80 percent conversion in the reactor, and 90 percent recovery after the reactor. Outline the types of equipment necessary for the process. Determine approximate duties of heat exchangers and list overall heat balances on the plant. It is known that the heat of formation of THF is -59.4 kcal/g mol, H,S is -4.77 kcal/g mol, and thiophane is - 17.1 kcal/g mol.

What additional information would be required in order to complete the project analysis?

Physical properties:

THF MW=72 sp gr = 0.887 Boiling pt. = 65°C

Vap. press. at 25°C = 176 mm Hg

Thiophane, MW = 88 Boiling pt. = 121°C