• Resources Recycling
• /
• v.17 no.5
• /
• pp.28-36
• /
• 2008

The effect of attrition scrubbing on the recovery of platinum group metals (PGMs) from automobile catalytic converters has been investigated. Catalytic converters were first crushed into particles less than 2 mm and attrition scrubbed in the range of 60 min, and then they were sieved with several screens. The catalyst layer, $\gamma$-alumina, was dislodged from the surface of the supporting matrix into fine particles less than $45{\mu}m$ by attrition scrubbing. The fraction of fine particles less than $45{\mu}m$ increased as the residence time for attrition scrubbing increased. The composition of the fine fraction obtained at a residence time of 40 min was $CeO_2$ 19.3%, $ZrO_2$ 1.9% and PGMs 419 ppm. In the fine fraction, the recovery of y-alumina increased proportionally to the residence time. Simultaneously, the recovery rates of $CeO_2$, $ZrO_2$ and PGMs increased to 82.9%, 78.7% and 78.9%, respectively. The production of the fine fraction less than $45{\mu}m$ and the recovery of $\gamma$-alumina increased when the solid concentration and initial feed size increased. Therefore, the attrition scrubbing as the comminution and separation process was concerned to be effective for the recovery of catalyst layer from ceramic supporting matrix by physical impact and shearing action between particles in the scrubbing vessel.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.110.2-110.2
• /
• 2010

현재 상용가능한 연소전 $CO_2$ 포집 기술은 습식 스크러빙 방식으로 고온의 합성가스를 상온 수준으로 온도를 낮춘 후 $CO_2$를 포집해야 하고 포집된 $CO_2$의 압력이 낮아 재압축하여 저장소로 보내야 함에 따라 큰 폭의 열효율 손실이 불가피하다. 고온 고압에서 이산화탄소를 포집할수 있는 고체 흡수제를 이용할 경우 이산화탄소 포집 치 저장 추가에 따른 시스템 효율 저하를 최소화할 수 있다. 고체 $CO_2$ 흡수제는 서로 연결된 두 개의 유동층 반응기를 순환하면서 흡수탑에서는 합성가스 중의 $CO_2$를 흡수하고 재생탑에서는 고온의 수증기와 접촉하여 흡수된 $CO_2$를 다시 배출함으로써 재생된다. 따라서 건식 재생 $CO_2$ 흡수제는 유동층 공정에 응용가능한 물성과 함께 높은 $CO_2$ 흡수능과 빠른 반응성이 요구된다. 본 연구에서는 유동층 공정에 적합한 물성을 가진 연소전 $CO_2$ 포집용 고체 흡수제를 분무건조법으로 제조하였으며, 모사 합성가스를 이용하여 열중량분석기와 기포유동층반응기를 이용하여 $200^{\circ}C$ 흡수, $400^{\circ}C$ 재생, 압력 20 bar 조건으로 반응성을 측정하였다. 개발된 고체 $CO_2$ 흡수제는 열중량분석기에서는 반응 후 10-13 wt%의 무게증가를 나타내었고 기포유동층반응기에서는 8-10 wt%의 $CO_2$ 흡수능을 보여주었다. 특히 수증기의 함량이 10% 이상에서 높은 흡수능을 나타내어 수증기가 반응에 크게 작용하고 있음을 알 수 있었다.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.107.1-107.1
• /
• 2010

고체 흡수제를 이용한 석탄합성가스 중의 황제거 기술은 습식 스크러빙 방식에 비해 고온에서 운전가능하므로 석탄가스화복합발전의 효율 향상을 가져올 수 있다. 고체탈황제는 서로 연결된 두 개의 유동층 반응기를 순환하면서 흡수탑에서는 합성가스 중의 $H_2S$로부터 황을 흡수하고 재생탑에서는 공기 중의 산소와 흡수된 황이 반응하여 $SO_2$를 배출하고 재생된다. 따라서 고체 황 흡수제는 유동층 공정에 응용가능한 물성과 함께 높은 황흡수능과 빠른 반응성이 요구된다. 본 연구에서는 기존 개발된 고체 탈황제가 가졌던 소성시 수축 현상, 낮은 내마모도 등을 개선하기 위해 지지체 조성을 변경하여 개발한 분무성형 탈황제의 흡수 재생 온도에 따른 황흡수 특성 변화를 조사하였다. $H_2S$ 1 vol. %를 함유한 모사 합성가스를 이용하여 흡수온도 450, $500^{\circ}C$, 재생온도 500, 550, 600, $650^{\circ}C$에서 황 흡수능을 열중량분석기를 이용하여 측정하였다. 개발된 흡수제는 유동층 공정 적용에 적합한 훌륭한 물성(형상, 밀도, 강도 등)과 함께 $500^{\circ}C$ 흡수와 $650^{\circ}C$ 재생을 기준으로 10 wt% 이상의 높은 황흡수능을 보여주었다. 흡수온도 변화는 황 흡수능 변화에 큰 영향을 미치지 않았으나, 재생온도가 $600^{\circ}C$ 이하인 경우 황흡수능이 5 wt% 이하로 크게 떨어져 재생온도를 $650^{\circ}C$ 이상 유지시키는 것이 중요함을 알 수 있었다.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.3
• /
• pp.186-192
• /
• 2023

According to the regulation on the pollution of the marine environment, SOx emission from ships has to be reduced. A SOx scrubbing system installed in a funnel of a ship is considered in order to reduce SOx emission. A scrubbing layer with a porous material is present in the funnel to increase the contact area between exhaust gas and water. In this study, experiments on the pressure drop characteristics in the scrubbing layer are conducted to investigate the effect of the scrubber on the engine load. The pressure drop according to flow rate of air instead of exhaust gas was measured for fillers such as sphere, pall ring and saddle in the scrubbing layer. First of all, porosity is experimentally measured for the three types of filler and it is confirmed that the porosity of the saddle-type filler was the largest. The pressure drop according to the change in air flow rate was measured for the three types of fillers in the scrubbing layer. As a result, the pressure drop was the smallest in the scrubbing layer with the saddle-type filler which has the largest porosity. In addition, the effect of spraying water flowing counter flow against air flow is experimentally examined. It is known that the pressure drop is increased because the air flow space is reduced when water is sprayed. In the case of the saddle, the pressure drop is about 1.5 to 2 times greater than that when only air flows at the optimum exhaust gas-water injection ratio.

• Membrane Journal
• /
• v.30 no.2
• /
• pp.97-110
• /
• 2020

CO₂ capture and storage (CCS) is one of the promising technologies that can mitigate ever-growing emission of anthropogenic carbon dioxide and resultant climate change. Among them, chemical looping combustion (CLC) and calcium looping (CaL) are getting increasing attention recently as the prospective alternatives to the existing amine scrubbing. Both methods use metal oxides in the process and consist of cyclic reactions. Yet, due to their cyclic nature, they both need to resolve sintering-induced cyclic stability deterioration. Moreover, the structure of the metal oxides needs to be optimized to enhance the overall performance of CO₂ capture and storage. Deposition of thin film coating on the metal oxide is another way to get rid of wear and tear during the sintering process. Chemical vapor deposition or atomic layer deposition are the well-known, established methods to form thin film membranes, which will be discussed in this review. Various effective recent developments on structural modification of metal oxide and incorporation of stabilizers for cyclic stability are also discussed.