• Journal of Power System Engineering
• /
• v.19 no.4
• /
• pp.30-35
• /
• 2015

The purpose of this study is to identify the low temperature performance and strength characteristics of V-based extruded homogeneous SCR. The extruded catalyst and the coated catalyst showed 50% and 27% of NOx conversion performance respectively at about $210^{\circ}C$ of catalyst temperature, so the extruded SCR was higher in de-NOx performance than the coated SCR especially at a low temperature zone. The compressive strength of the Enhanced Extrusion #1, in which the content of promoters such as silica, clay, glass fiber and binder was optimized, was a 120% improvement compared to the Extrusion#1 catalyst, higher than the coated SCR.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.06a
• /
• pp.735-738
• /
• 2009

촉매 생산에서 마지막으로 중요한 단계는 촉매성형이다. 여기서 압출성형은 촉매 성형방법 중 저렴하고 비교적 간단한 방법 중 하나이다. 여기서 중요한 것은 바인더의 선택과 입자 사이즈가 가장 중요한 요인이 된다. 촉매 압출성형에서 많이 쓰이는 바인더로 PVA(Polyvinyl Alcohol)와 MC(Methyl Cellulose), CMC(Carboxymethyl Cellulose)가 있다. CMC 바인더의 경우, 촉매의 접착력이 현저히 떨어져 촉매의 바인더로 사용하기 어려웠다. PVA, MC 바인더의 경우, 촉매의 접착력이 우수하고 압출성형이 잘 되었다. 그러나 PVA 바인더의 경우, 열중량 분석을 통해 재 소성과정에서 바인더가 완전히 제거되지 않아서 촉매의 물성 변화 및 활성에 좋지 않은 영향을 주었다. 그러나 MC의 경우에는 재소성과정에서 바인더가 완전히 제거되어 촉매의 물성변화에 영향을 주지 않았으며, 촉매의 활성 변화에도 영향을 주지 않았다. 그래서 메탄 수증기 개질 촉매의 압출 성형에 적합한 바인더로 MC가 적합하다고 판단된다. 그리고 압출용 반죽 제조를 위한 미분쇄된 촉매 입자의 사이즈에서 너무 작은 입자를 사용하게 되면 반죽은 잘 되나 촉매의 물성변화로 인해 촉매 활성이 저하되는 것을 알 수 있었다. 그래서 볼밀로 정밀하게 입자 사이즈를 $10{\mu}m$ 이하로 조절하면 촉매 활성에 영향이 거의 없는 압출성형 촉매를 제조할 수 있다.

• Journal of Ceramic Processing Research
• /
• v.20 no.5
• /
• pp.464-469
• /
• 2019

In this study, the electrical conductivity of multi-walled carbon nanotubes (MWCNTs) and polyethylene synthesized by an extrusion process was evaluated. The MWCNTs used exhibited differences in their dispersion characteristics depending on the type of catalyst or synthesis gas used. Thus, the choice of catalyst or synthesis gas significantly affect the physicochemical state of the final MWCNTs and MWCNT-based composites. In this investigation, the characteristics of MWCNTs were analyzed in four cases by introducing ethylene and propylene gas to each catalyst synthesized using deposition precipitation and spray drying methods. The MWCNT-based composites synthesized using the catalyst prepared by deposition precipitation and the ethylene synthesis gas showed the best electrical conductivity. In principle, the morphologies of the MWCNTs indicate that the smaller the aggregate size and bundle thickness, the better the electrical conductivity of the MWCNT composites. This implies that the network is well-formed.

• Preventive Nutrition and Food Science
• /
• v.2 no.4
• /
• pp.296-300
• /
• 1997

Glucose syrup and lactose, mixed with citric acid as a polymerizing catalyst, was processed using twin screw extruder, in which 40 of L/D(length/diameter) ratio was designed to provide sufficient retention in extruder for polymerization of sugars. The polymerization yields of glucose syrup were 36.90%, 55.44% and 77.10% at 160, 180 and 20$0^{\circ}C$, respectively, while those of lactose were 26.45%, 38.16% and 45.86% at the same temperatures. Gel permeation chromatography exhibited that the higher molecular weight fractions were increased with extrusion temperature, which also led to increasing hydrodynamic intrinsic viscosity. Both uco-oligosaccharides and lacto-oligosaccharides produced by extrusion of glucose syrup and lactose were stable for thermal treatments over a wide range of pH3.0~11.0. In addition, $\alpha$-amylase and amyloglucosidase treatment of gluco-oligosaccharides did not affect the solution viscosity, indicating the random linkage rather than $\alpha$-1, 4 linkages of glucose and thus the potential applications as a dietary fiber. In this research it was clearly observed that twin screw extrusion can be successfully utilized to produce gluco-oligosaccharides and lacto-oligosaccharides rapidly and continuously in conjunction with selective control of polymerized composition.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.10a
• /
• pp.16-20
• /
• 2003

As the preliminary works for the preparation of exfoliated nanocomposites by reactive extrusion (REX) the modified anionic polymerization proceeded in a flask using an $\varepsilon$-caprolactam, catalyst, initiator, and clay. Polymerization methods were classified with a variation of the clay adding time. Intercalations mechanism of clay layers was investigated by measuring the WAXD peaks of clay with polymerization. In the preparation of nanocomposites, the molecular weight of nylon 6 was affected by the clay content. From the mechanical property measurement, improved properties were obtained in comparison to the neat nylon 6, and these properties were also affected by the molecular weight.

• Applied Chemistry for Engineering
• /
• v.28 no.2
• /
• pp.193-197
• /
• 2017

In this study, we report on the catalyst process installed in conjunction with a wet plasma electrostatic precipitator to remove the oil mist and fine dust emitted from large-size grill restaurants. The multi-stage catalyst module reduced odor through catalytic reaction of acetaldehyde on catalysts even at an ambient temperature with ozone as an oxidant readily produced in a wet plasma electrostatic precipitator. Two types of manganese-based catalysts, $Mn_2O_3$ and $CuMnO_x$ were fabricated by extrusion molding for structured catalysts in practical applications, and the optimum conditions for high removal efficiencies of acetaldehyde and ozone were determined. When two optimized catalysts were applied in a two-stage catalyst module, the removal efficiency of acetaldehyde and ozone were ${\geq}85%$ and 100% respectively at the space velocity of $10,000h^{-1}$ and the reaction temperature of $100^{\circ}C$.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
• /
• 2001.06a
• /
• pp.1284-1284
• /
• 2001

The transesterification of molten ethylene/vinylacetate (EVA) copolymers by octanol as a reagent and sodium methoxide as a catalyst in an extruder has been monitored by on-line near infrared (NIR) spectroscopy. A total of 60 NIR spectra were acquired for 37 minutes with the last spectrum recorded 31 minutes after the addition of octanol and catalyst was stopped. The experimental spectra show strong baseline fluctuations which are corrected for by multiplicative scatter correction (MSC). The chemometric methods of orthogonal projection approach (OPA) and multivariate curve resolution (MCR) were used to resolve the spectra and to derive concentration profiles of the species. The detailed analysis reveals the absence of completely pure variables that leads to small errors in the calculation of pure spectra. The initial estimation of a concentration that is necessary as an input parameter for MCR also presents a non-trivial task. We obtained results that were not ideal but applicable for practical concentration control. They enable a fast monitoring of the process in real-time and resolve the spectra of the EVA copolymer and the ethylene/vinyl alcohol (EVAL) copolymer to be very close to the reference spectra. The chemometric methods used and the decomposed spectra are discussed in detail.

• Clean Technology
• /
• v.24 no.4
• /
• pp.371-379
• /
• 2018

The objective of this study is to develop a platinum/hexaaluminate pellet catalyst for the decomposition of eco-friendly liquid propellant. Pellet catalysts using hexaaluminate prepared by ultrasonic spray pyrolysis as a support and platinum as an active metal were prepared by two methods. In the case of the pellet catalyst formed by loading the platinum precursor onto the hexaaluminate powder and then adding the binder (M1 method catalyst), the mesopores were well developed in the catalyst after calcination at $550^{\circ}C$. However, when this catalyst was calcined at $1,200^{\circ}C$, the mesopores almost collapsed and only a few macropores existed. On the other hand, in the case of a catalyst in which platinum was supported on pellets after the pellet was produced by extrusion of hexaaluminate (M2 method catalyst), the surface area and the mesopores were well maintained even after calcination at $1,200^{\circ}C$. Also, the catalyst prepared by the M2 method showed better heat resistance in terms of platinum dispersion. The effects of preparation method and calcination temperature of Pt/hexaaluminate pellet catalysts on the decomposition of liquid propellant composed mainly of ammonium dinitramide (ADN) or hydroxyl ammonium nitrate (HAN) were investigated. It was confirmed that the decomposition onset temperature during the decomposition of ADN- or HAN- based liquid propellant could be reduced significantly by using Pt/hexaaluminate pellet catalysts. Especially, in the case of the catalyst prepared by the M2 method, the decomposition onset temperature did not show a large change even when the calcination temperature was raised at $1,200^{\circ}C$. Therefore, it was confirmed that Pt/ hexaaluminate pellet catalyst prepared by M2 method has heat resistance and potential as a catalyst for the decomposition of the eco-friendly liquid propellants.

• Korean Chemical Engineering Research
• /
• v.49 no.6
• /
• pp.726-731
• /
• 2011

The technology enabling the large-scale production of catalysts by extrusion is very important for the commercialization of the Fischer-Tropsch process. In this study, the influence of the binder on the extrudate of Fe-based catalyst well known as FT catalysts has been studied. Inorganic binders such as kaolin, bentonite, alumina sol and silica sol and organic binders were added during extrudate preparation. The extrudates have been prepared with various compositions, and the physicochemical properties of the extrudates have been examined by XRD, BET, PSD, TPR and UTM. The optimum binder composition of extrudate was established by comparing the FT reaction activity.

• Clean Technology
• /
• v.23 no.2
• /
• pp.133-139
• /
• 2017

Bio-based plastics containing the biomass content higher than 25 wt% have been considered as environment-friendly materials due to their effects on the reduction in the $CO_2$ emission and petroleum consumption as well as biodegradability after use. In this study, poly vinyl chloride, plant-derived plasticizers, by adding a biodegradable catalyst was observed a change in the biodegradability and physical properties. To produce the oxidative decomposition transparent bio film, which is broken down in the initial percent elongation and physical properties such as tensile strength, it was to test the safety of the product as a food packaging material. Poly vinyl chloride, primary plasticizer, secondary plasticizer, anti fogging agent, the combined stabilizer were mixed in a high speed mixer, then extruded using an extrusion molding machine, after cooling, winding, to produce a oxidative decomposition transparent bio film and the control film, with a thickness of $12{\mu}m$ through winder role. Mechanical properties tensile strength, elongation, and the maximum load elongation and biodegradation test. Transparent bio film produced by biodegradation catalyst is compared with the control film. Tensile strength and elongation of films were found to be no significant difference. Further, as a result of the biodegradation test for 45 days based on the ASTM D6954-04 method, biodegrability of film is 61.4%.