| Summary: | 博士 === 國立清華大學 === 工程與系統科學系 === 93 === The Environmental Protection Administration of Taiwan will soon enforce the ”Opto-Electronic Manufacturers�S Air Pollution Control and Emission Standard”. The VOCs emission quantity is thus expected to be controlled with special focuses on the next generation of TFT-LCD manufacturers. One of the most popular VOCs treatment equipments for the next generation of TFT-LCD manufacture fab is the thermal swing adsorber includes honeycomb zeolite rotor with thermal oxidizer and granular bean activated carbon (GBAC)fluidized bed with condenser unit. However limited information is available on these thermal swing absorbers in the literature.
This study intends to provide experimental data and discuss the performance of the thermal swing adsorbers of honeycomb zeolite rotor and granular bean activated carbon fluidized bed for the VOCs exhaust laden air that simulated the emission characteristics of an opto-electronic manufacturer�Ss fab. The major VOCs compounds are IPA、Acetone、PGME、 PGMEA 、HMDS、 Cyclohexanone and Strippers in the VOCs laden exhaust air.
The results of honeycomb zeolite rotor portion showed that the affinity of the high boiling point VOCs such as PGME and PGMEA on the zeolite rotor is much larger than that of the low boiling point VOCs such as IPA and acetone, it followed the order of PGMEA ≧ PGME>> IPA> acetone, that is caused by competitive adsorption and adsorption replacement effect. And the adsorption isotherm of zeolite rotor can be represented by D-A and Freundlich isotherms, but not Langmuir isotherm. Under proper operation conditions of reducing the superficial velocity and the concentrate ratio, and increasing the desorption temperature or the thickness of the rotor, the THC removal efficiency can be easy and well above 90% and thus meet the promulgating regulation.
And the results of granular bean activated carbon fluidized bed portion showed that IPA and PGME will pyrolysis to propene when desrob temperature higher than 250oC,the convert rate will be above 90% of IPA and 50% of PGME,finally this propene will carbonize to amorphous carbon and plug in the micro pores after repetitious thermal swing ; some polymer compounds as MEA 、styrene and cyclohexanone result polymerization when repetitious thermal swing on the GBAC, these compounds remain in the GBAC pores and reduces the adsorption capacity, and cyclohexanone can easily oxidization on the surface of GBAC, hence fluidized bed system need the pre-treatment for these harmful compounds pre-treating before entrance fluidized bed.
|
|---|
