Experimental Investigation of Ozone Decomposition in Diesel Particulate Filter Regeneration with Non-Thermal Plasma Technology

Wang Weikai,Cai Yi-xi,Shi Yunxi,Wang Jing,Zhao Nan,Ji Liang 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.4

A non-thermal plasma (NTP) reactor was used to generate ozone for diesel particulate filter (DPF) regeneration. The kinetic mechanism of ozone thermal decomposition reaction is explored, and the effect of temperature on the change of ozone concentration is analyzed. The changes of the internal temperature and the concentration of regeneration products such as CO2 and CO during the regeneration under constant temperature and non-constant temperature conditions are then studied and the influence of different regeneration environments on the regeneration is analyzed in combination with the decomposition law of ozone. In the non-constant temperature condition, DPF surface temperature changes significantly with time. The results show that when using an NTP reactor to generate ozone, the activation energy of the decomposition reaction is 2.80755 × 104 J/mol and the law of thermal decomposition reaction can be described as 190.76 . /. During DPF regeneration, the overall regeneration rate and ozone utilization rate in the nonconstant temperature environment are higher than in the constant temperature environment and the temperature change (delta-T) peak rises with the increase of PM deposition. The regeneration with NTP under non-constant thermal condition is an effective way to improve the efficiency of DPF regeneration.

오존수 산화를 이용한 활성탄 흡착탑의 현장 재생 시 흡착용량 및 구조특성의 변화

이진주 ( Jinjoo Lee ),이기세 ( Kisay Lee ) 한국공업화학회 2020 공업화학 Vol.31 No.3

하폐수처리 및 정수처리에 사용되는 활성탄 흡착 공정에서 기존의 활성탄 열재생법 비해 활성탄 손실과 불완전 연소로 인한 오염물질 발생도 적으며, 사용 활성탄의 인발-재생-재충진에 소요되는 시간의 절약이 가능한 재생 방법으로 오존수를 이용한 in situ regeneration에 대한 기초연구를 수행하였다. 활성탄 흡착 컬럼 상에서 페놀(phenol) 및 PEG를 흡착 파과 시킨 후 오존수 접촉으로 흡착물질을 분해 제거하는 흡착-재생 싸이클을 반복하였다. 오존수 접촉에 의한 재생 횟수가 증가할수록 페놀 흡착용량은 어느 정도 감소하지만, 일정 수준으로의 감소 후에는 구조 변화가 안정화되어 추가적인 감소가 일어나지 않았다. 흡착 용량이 감소하는 이유는 오존과의 반응에 의해 활성탄의 미세공 크기가 증가하면서 비표면적이 감소하기 때문으로 나타났다. 이러한 세공 크기의 변화와 비표면적의 변화로 인하여 재생 후 in-pore adsorption이 우세한 페놀과 같은 저분자량 물질의 흡착효율은 감소하게 되나 external adsorption 비율이 큰 PEG와 같은 고분자량 물질의 흡착효율은 크게 영향을 받지 않았다. 세공 크기 및 비표면적의 변화는 오존수와의 접촉시간이 길어질수록 심화되므로 제거하려는 물질의 크기를 고려하고 접촉시간을 조절함으로써 흡착 효율의 유지를 제어하는 것이 필요하다. An in situ regeneration of activated carbon bed using an ozonated water was studied in order for avoiding the carbon loss, contaminant emission and time consuming for discharge-regeneration-repacking in a conventional thermal regeneration process. Using phenol and polyethylene glycol (PEG) as adsorbates, the adsorption breakthrough and in situ regeneration with the ozonated water were repeated. These organics were supposed to degrade by the oxidation reaction of ozone, regenerating the bed for reuse. As the number of regeneration increased, the adsorption capacity for phenol was reduced, but the change was stabilized showing no further reduction after reaching a certain degree of decrement. The reduction of adsorption capacity was due to the increase of pore size resulting in the decrease of specific surface area during ozonation. The adsorption capacity of phenol decreased after the ozonated regeneration because the in-pore adsorption was prevalent for small molecules like phenol. However, PEG did not show such decrease and the adsorption capacity was constantly maintained after several cycles of the ozonated regeneration probably because the external surface adsorption was the major mechanism for large molecules like PEG. Since the reduction in the pore size and specific surface area for small molecules were proportional to the duration of contact time with the ozonated water, careful considerations of the solute size to be removed and controlling the contact time were necessary to enhance the performance of the ozonated in situ regeneration of activated carbon bed.

Regeneration and purification of water-soluble cutting fluid through ozone treatment using an air dielectric barrier discharge

Ma, Sukhwal,Kim, Kangil,Huh, Jinyoung,Kim, Da Eun,Lee, Sangju,Hong, Yongcheol Elsevier 2018 Separation and purification technology Vol.199 No.-

<P><B>Abstract</B></P> <P>Cutting fluids are essential for cutting performance and rust prevention in metalworking processes. Among cutting oils, the usage of water-soluble cutting fluids is increasing rapidly because they afford excellent cooling performance and ensure fire safety. However, water-soluble cutting fluids also offer a favorable environment for the growth of a wide variety of microorganisms. The growth of microorganisms can lead to various problems such as deterioration of the cutting fluids and odor generation. Thus, technologies for purifying the waste of water-soluble cutting fluids are required. In this study, we developed an ozone treatment technology that uses an air DBD plasma system. Furthermore, sterilization experiments were performed with <I>K</I>. <I>pneumoniae</I>, <I>P</I>. <I>aeruginosa</I>, <I>E</I>. <I>coli</I>, <I>and P. vulgaris</I> as representative microorganisms. The system offers the advantages of low power consumption and simple structure. Approximately 1000 ppm of ozone could be stably generated under optimized conditions, and the ozone was injected into the reactor as micro-bubbles for improving reactivity and inactivation rate. The sterilization experiments confirmed that the water-soluble cutting fluid was sterilized by 99.99%. As a result, the turbidity, pH, and odor of water-soluble cutting fluid have been improved.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An air DBD plasma system is developed to treat water-soluble cutting fluids with ozone. </LI> <LI> The system consumes less power and requires less space. </LI> <LI> A suitable amount of ozone can be stably generated under optimized conditions. </LI> <LI> The water-soluble cutting fluid was sterilized by 99.99%. </LI> <LI> pH, turbidity, and odor were improved with the bacterial inactivation. </LI> </UL> </P>

망간산화물 촉매와 오존을 이용한 아세트알데하이드 산화과정에서 상대습도의 영향

조준표,송지현 한국냄새환경학회 2022 실내환경 및 냄새 학회지 Vol.21 No.3

This study was performed to investigate the effects of water molecules on ozone oxidation of acetaldehyde using a manganese oxide catalyst at room temperature. The catalytic ozone oxidation was conducted at different relative humidity (RH) conditions of 0%, 50%, and 80%. As the RH increased, both ozone and acetaldehyde removal efficiencies dropped due to competitive adsorption on the surface of the catalyst. At the highest RH of 80%, the oxidation reaction was severely retarded, and oxidation by-products such as acetic acid were formed and adsorbed on the surface. After the ozone oxidation of acetaldehyde, the regeneration of the catalyst using ozone alone was tested, and the further oxidation of accumulated organic compounds was investigated under the RH conditions of 0%, 50%, and 80%. When the highest relative humidity was introduced in the regeneration step, the ozonation reaction with the by-products adsorbed on the catalyst surface decreased due to the competitive reaction with water molecules. These findings revealed that, only when relative humidity was low to minimize the formation of by-products, the ozone oxidation of acetaldehyde using the manganese oxide catalyst at room temperature can be feasible as an effective control method. .

Regeneration of Diesel Particulate Filter (DPF) using Ozone

Jae-ou Chae(채재우),Xin-hong Chen(진신홍),C. Purushothama(푸루소타마),Rui-qiang Liu(류서강),Ming-wei Li(이명위) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6

Recent years, automotive diesel engine emission standards become very strict, and it is hard to fulfill them just by using the current techniques of improving combustion. Therefore, the ceramic diesel particulate filter (DPF) is widely used for collecting soot from the exhaust gas of diesel engine. However, the DPF need being regenerated after the soot accumulation. This research deals with regeneration of the DPF using ozone, which comes from surface discharge occurred in a dielectric barrier discharge reactor. Pure oxygen was introduced into the reactor, and was discharged to form much activated species, including ozone and monatomic oxygen. When pure oxygen of 4 L/min at a temperature of 443 K is passed to the DPF through plasma reactor which is energized by 100 W for two hours, it has found a decrease in weight of soot by 2 grams. Comparing with the regenerating method via NO₂, the method using ozone is much friendlier to the environment, because ozone is very unstable.

백금담지 알루미나 촉매와 오존 산화제 동시 적용에 의한 탄소 입자상 물질의 저온 산화반응

이진수 ( Jin Soo Lee ),이대원 ( Dae-won Lee ) 한국화학공학회 2018 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.56 No.5

The lowering of temperature for combustion of diesel particulate matters (or diesel soot) is one of the important tasks in automotive industry that is searching for a way to meet up “high-fuel efficiency, low-emission” standard. In this study, it was discussed how the use of ozone over platinum-based catalyst promotes a low-temperature soot oxidation occurred at 150 ℃. The use of platinum catalyst did not increase oxidation rate largely but was very effective in improving the selectivity of carbon dioxide. The pre-oxidation of NO into NO₂ using ozone was rather crucial in improving the oxidation rate of soot at 150 ℃.

인쇄업에서 배출되는 반응성 VOCs 종류와 흡착 제거 방법의 적용

안해영,송지현,이윤경 한국냄새환경학회 2018 실내환경 및 냄새 학회지 Vol.17 No.4

In this study, volatile organic compounds (VOCs) emitted from printing industries were analyzed, and an inorganicadsorbent, γ-alumina, was selected for the effective control of the VOC emissions. Printing processes commonlyrequire inks, thinners, and cleaners, and they were mixed organic solvents containing aromatic compounds, ketones,and alcohols. Therefore, toluene, methyl ethyl ketone (MEK), and isopropyl alcohol (IPA) were selected as modelcompounds for this study. The adsorptive properties using γ-alumina were determined for the model compounds. Both batch isotherm and continuous flow column tests demonstrated that the adsorption capacity of MEK andIPA was 3~4 times higher than that of toluene. The column test performed at an inlet toluene concentration of100 ppm showed that an 80% breakthrough for toluene was observed after 3 hours, but both MEK and IPA werecontinuously adsorbed during the same time period. A numerical model simulated that the γ-alumina could removetoluene at a loading rate of 0.4 mg/min only for a 4-hour period, which might be too short of a duration for realapplications. Consequently, lifetime enhancement for γ-alumina must be implemented, and ozone oxidation andregeneration would be feasible options.