Low temperature desorption of the used activated carbons that contain VOCs (Volatile Organic Compounds) produced from Shiwha/Banwal industrial complex were investigated. Iodine number and BET specific surface area of the activated carbons manufactured by N company in China were measured to see their characteristics prior to use in the experiment. Activated carbons were used to adsorb VOCs in a company of Shiwha/Banwal complex. Used activated carbons were collected and desorbed by the desorbing facility. After 1st adsorption and 1st desorption samples were taken for analysis. Desorbed activated carbons were reused in the same company. After 2nd adsorption and 2nd desorption samples were taken again for analysis. 4 samples were analyzed by TGA (Thermogravimetric Analyzer) at 170℃ with a heating rate of 10℃/min. Also, activation energies and reaction orders of desorption reaction were assessed by employing Friedman method and Freeman-Carroll method. The activation energies were 16.86kJ/mol by Friedman method and reaction orders were 0.36∼5.16 by Freeman-Carroll method.

In this study, the removal characteristics of reduced sulfur compounds (RSC) were investigated against activated carbon (AC) by means of electric cooling and thermal desorption. To this end, three types of AC materials were selected and tested against gaseous RSC standards prepared at 50 ppb concentration. Each of these AC materials designated with its own target odorant compounds was tested for the removal rate of RSC by comparing their quantities between prior to and after passing the adsorption tube. All the analysis of RSC was made by Gas Chromatography (GC)/Pulsed Flame Photometric Detector (PFPD) combined with Air Server (AS)/Thermal Desorber (TD). The rate of RSC removal was quantified as a function of RSC loading time (Exp. 1) and of RSC flow rate into TD (Exp. 2). The results of Exp. 1 showed that the adsorption of RSC increased with RSC loading time (from as little as 1 to 20 min). In Exp. 2, the adsorption of RSC also increased in relation to RSC flow rate (10 to 100 mL/min). The removal rate of RSC was also distinguished by chemical properties such as the compounds of low molecular weights (H₂S and CH₃SH) vs. high ones (DMS and DMDS).

In this study, we attempt to analyze for 4 compounds (MEK, MIBK, n-Butyl acetate, i-Butyl alcohol) in ambient air using on-line thermal desorber (on-line TD) with gas chromatograph/flame ionization detector (GC/FID). These compounds will be regulated by KMOE (Korean ministry of environment) within 2010. We tested two different experimentation. First, we try to find the influence of Nafion dryer for the 4 compounds. Second, we want to know basic analytical characteristic of target compounds through the linearity, reproducibility, and minimum detection limit. According to this study, target compounds are removed in Nafion dryer more than 80 percent, respectively. So, we progressed next experimentation progressed without Nafion dryer using hydrophobic cold trap. Results for each compounds showed good linearity (r²＝0.99 upper) and good precision (RSD＝1 % below). In additional, we analyzed the ozone precusors standard gas (56 compounds) using the same method to see if there are any peaks to be overlapped in ambient air. These results showed that there is no peak overlapped. This means that analytical system of this study could be used on-line analytical system. Minimum detection limit (MDL) value for this system are less than minimum malodor threshold concentration.

In this study, the low-temperature vacuum swing adsorption (low temp. VSA) process was applied to the activated carbon adsorption tower for treatment of volatile organic compounds (VOCs) to extend the replacement period of the adsorbent and to solve the difficulties of operation management. A practical application study was performed based on continuous operation in the field. The VSA process removes the adsorbate by reducing the pressure at a relatively low temperature (90℃ or less) to compensate for the disadvantages of the conventional thermal swing adsorption (TSA) process. A pilot scale VSA process with a size of 30 m and 2 min−1 was applied to the small scale painting plant, which is the main source of VOCs, and subject to 100 adsorption/desorption cycles. After the sampling of activated carbon every 20 cycles, the specific surface area and derivative thermogravimetric analysis (DTA) analysis were investigated to analyze the change of activated carbon characteristics with increasing cycles. During 100 continuous cycles, toluene gas was arbitrarily supplied to the pilot VSA process to compare toluene adsorption capacity with respect to raw activated carbon. More than 99% of the VOCs emitted from the paint plant were adsorbed and removed during the operation of the VSA process. The increase in cycle did not affect the specific surface area and micropores of activated carbon. However, the physical adsorption amount of the non-desorbed adsorbate remaining in the micropores tends to increase; therefore, it is considered that the effective adsorption amount decreases as the number of regeneration increases. As a result of the toluene adsorption test of the pilot plant after 100 consecutive cycles, 91% removal efficiency relative to the raw activated carbon was maintained. Thus, stable application of low-temperature VSA equipment is feasible in field application.

VOCs는 화학공장에서 방출되는 휘발성 유기물질이며, SOx, NOx등과 함께 최근 심각한 대기오염의 주요인이 되는 물질이다. 주요 발생원으로는 주유 시, 또는 운송 중에 휘발되는 자동차나 제조 시, 또는 각 산업의 도장 공정에서 발생되는 페인트 산업, 인쇄 혹은 세탁시설 등의 세정제 등에서 발생되며, 이의 적절한 처리방법의 개발이 필요한 실정이며, 효율적인 처리와 탈착 후 VOC회수를 동시에 가능케 하는 방안이 개발되어야 할 것이다. 이러한 방법 중 하나로 저온 VSA방식을 통한 흡･탈착 방법이 모색되고 있다. 본 연구는 랩 규모의 VOC흡탈착 장치를 이용하여 온도, 압력별 탈착 성능 평가하였고 이를 통하여 최적 처리조건 도출하였다. 또한 반복 운전시 내구성 확보가 가능한 흡착소재 선정을 위해 활성탄, 활성탄소섬유, 제올라이트, 알루미나 등의 다양한 흡착제를 통하여 VOC 흡･탈착을 수행하였다.