*2.4. Laboratory and Pilot Chemical Plants*

The ethanol dehydrogenation kinetic data, related to the previous section, have been collected in a laboratory chemical plant, as schematized in Figure 2 [42].

**Figure 2.** A1—Ethanol tank; A2—HPLC pump; A3, A5—Check valves; A4—relief valve; A6—Flow mass controller, A7—Cylinder containing a mixture of hydrogen 5% and nitrogen; A8—pre-heater to vaporize ethanol; A9—Stainless steel packed bed tubular reactor. A10—Back pressure regulator; A11—Heat exchanger; A13, A14—Product tanks raising; A12/A15—Liquid nitrogen dewars; S1/S2/S5—Temperature probes; S3/S4—Pressure transducers. The reactor A9 was heated by two independently thermoregulated heaters.

Recently, Semenov et al. [10] published a work describing the performance of a pilot plant working with a Cu-ZnO catalyst. A scheme of the employed pilot plant, containing 0.5 L of catalyst, is shown in Figure 3. The authors worked in a temperature range of 503–573 K and 1–20 atm. The best obtained results were 63% of ethanol conversion per pass and 94% of selectivity to ethyl acetate, together with very small amounts of side products such as butyl alcohol, butyl acetate, and ethyl butyrate. Moreover, the catalyst remained stable during all the time investigated in a long-term test (1250 h on stream).

**Figure 3.** Scheme of a pilot plant, containing 0.5 L of catalyst, used by Semenov et al. to verify catalyst stability in runs prolonged for 1250 h. (1) Raw material container; (2) Dosing pump; (3) Tubular fixed bed reactor; (4) Heating furnace; (5) Pressure gauge; (6) Movable thermocouple; (7) Temperature reading; (8) and (9) Temperature regulation system; (10) Ethyl acetate, ethanol condenser; (11)–(13) Hydrogen flow measurement; (15) Container to collect liquid produced; (16) Hydrogen bottle; (17) Pressure reducer; (18) valve.

However, considering the change of enthalpy passing from the dehydrogenation of acetaldehyde (endothermic) to the successive reaction of ethyl acetate formation (exothermic) it would be opportune, as before mentioned, to consider the reactor subdivided into two or three zones differently heated, as in the scheme of Figure 4.
