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Handbook of Solvents - George Wypych - ChemTech - Ventech!

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22.2 Solvent recovery 1545<br />

Basic design <strong>of</strong> VOC concentrator<br />

VOC concentrator consists <strong>of</strong> a VOC rotor, a rotor driving device, a rotor casing with<br />

a set <strong>of</strong> seals, a pair <strong>of</strong> chambers (front/rear) with a zone partition wall, and a desorption<br />

heater as shown in Figure 22.2.2.<br />

Figure 22.2.2. VOC concentrator.<br />

Advantages<br />

VOC concentrators, outstanding in their purifying and concentrating efficiency, have<br />

been used worldwide as a high-quality and safe product owing to material engineering expertise.<br />

By being combined with oxidizers, and other recovery equipment, the initial investment<br />

and running cost <strong>of</strong> the total system can be drastically diminished. Even for such<br />

VOCs as cyclohexane/MEK/ammonia/methyl alcohol/ethyl alcohol/styrene/formaldehyde/isophorone/phenol,<br />

which have been found unsuitable for the existing technology using<br />

activated carbon, due to economic or safety concerns, the VOC concentrator is costeffective<br />

and safe.<br />

• Non-combustible components - The development <strong>of</strong> non-flammable rotors has been<br />

achieved by engineering the appropriate materials for the honeycomb substrate, the<br />

adsorbent, and the binder and by application <strong>of</strong> special material processing<br />

technique.<br />

• Treatment <strong>of</strong> VOCs which have high boiling point - Taking advantages <strong>of</strong> zeolite<br />

rotors, non-combustible component, and high heat resistance, concentrators can use<br />

adsorption air at high temperatures. Accordingly, VOCs that could not be treated by<br />

carbon material due to its desorption temperature limit have turned out to be easily<br />

treated.<br />

• Inertness - VOCs that can easily polymerize, such as, styrene, cyclohexanone, etc.,<br />

can be effectively treated by hydrophobic zeolite.<br />

• Cleaning and reactivation - Zeolite rotors can be calcinated under high temperature,<br />

due to their all inorganic content (including binder). The rotors can be easily<br />

washed. Zeolite rotors can be reactivated by heat treatment.<br />

Table 22.2.2 shows the typical applications <strong>of</strong> the VOC concentrator.

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