(59y) Removal of Volatile Organic Contaminants from Air Via Thermal Separation Technique

Thermal separation technique with vacuum de-sublimation is one of advanced methods with industrial processes such as distillation; crystallization and solvent extraction .In the present study an experimental work with simulation model have been carried out to investigate performance of de-sublimator (cold trap) for removal of benzene from gases mixture of BTEX of vented air of a petroleum refinery in Baghdad. Gas chromatography-Mass spectrometer (GC-MS) was used to determine concentrations of Benzene, Toluene, Ethyl benzene and Xylene (BTEX) .The removal efficiency could affected by several operating variables, which are the important task for design and control of the thermal system. Four process variables selected which are: gas concentration; gas flowrate; bulk pressure and bulk temperature. Steady-state solidification process of BTEX was carried out in (0.05 m ID) cylindrical cold trap was made of stainless steel. The thickness of compact solid layer was measured by sophisticated ultrasonic gauge, while pressure and temperature were monitored by high accuracy transducers. Vacuum de-sublimation technique shows one of competitive and economical method when compared with the conventional operations. The bulk temperature has proven the most effective variable and the pressure has critical effect. The predictive mathematical model has been proven reliable for determine unmeasured parameters of heat and mass transfer for the highly interacted non-linear thermal system. Mass transfer operation was the control step at low temperature. Optimum results show that maximum value of removal efficiency (~99.5%) could obtained with high value of benzene concentration (>0.5) and with low values for; gases flow rate (<50 cc/min), bulk temperature (<-6 c ) and operating pressure(<3 mbar). Reasonable agreement has obtained when compared the simulated solutions with the experimental results.

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