Application of KF/MgO as a heterogeneous catalyst in the production of biodiesel from rapeseed oil

Yunbai Luo,Tao Wan,Shangkun Gong,Qiang Li,Ping Yu 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.5

Biodiesel was synthesized from rapeseed oil by transesterification over Magnesium oxide loaded with KF. The catalytic activity strongly depends on the loading amount of KF and calcined temperature. We found that the reaction reached a 79.37% yield when the loading amount was at 35 wt% and calcined at 500 oC. The simply dried 30% KF/MgO at 80 oC was found to give equally good results from the catalyst calcined at 500 oC, avoiding the usual activation at high temperature. The catalysts were characterized by the Hammett indicator method, BET, TG/DTG, XRD, NMR, EDS, and FT-IR. According to the instrumental analysis, the activity in the transesterification probably belonged to coordinately unsaturated F− and liberation of hydroxide during preparation. The effects of methanol/oil ratio and catalyst amounts on the conversion were also studied in this paper.

Performance characteristics of NO removal by cobalt diethylenetriamine solution

Houzhang Tan,Jinchao Wei,Yunbai Luo,Ping Yu 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.3

The cobalt(II) diethylenetriamine ([Co(dien)2]2+) complex is a newly developed metal thiochelate for the removal of NO from flue gas. The performance characteristics of NO absorption into [Co(dien)2]2+ solution were studied in a stirred reactor. The experimental results showed that this absorption could be regarded as fast pseudo-mth-order reaction and the reaction rate could be expressed as second-order with respect to NO concentration and first-order with respect to [Co(dien)2]2+ concentration. The enhancement factor was 1609.1 at the [Co(dien)2]2+ concentration of 0.01mol/L. Its optimal absorption conditions were temperature 50 oC, NO concentration 540 ppm, [Co(dien)2]2+ concentration 0.02 mol/L and O2 concentration 6%, which were determined by orthogonal experiment.

Renewable Low-viscosity Dielectrics Based on Vegetable Oil Methyl Esters

Hui Yu,Ping Yu,Yunbai Luo 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.2

Vegetable oil dielectrics have been used in transformers as green alternatives to mineral insulating oils for about twenty years, because of their advantages of non-toxic, biodegradability, and renewability. However, the viscosity of vegetable oils is more than 3 times of mineral oils, which means a poor heat dissipation capacity. To get low-viscosity dielectrics, transesterification and purification were performed to prepare vegetable oil methyl esters in this study. Electrical and physical properties were determined to investigate their potential as dielectrics. The results showed that the methyl ester products had good dielectric strengths, high water saturation and enough fire resistance. The viscosities (at 40℃) were 0.2 times less than FR3 fluid, and 0.7 times less than mineral oil, which indicated superior cooling capacity as we expected. With the assistance of 0.5 wt% pour point depressants, canola oil methyl ester exhibited the lowest pour point (-26℃) among the products which was lower than FR3 fluid (-21℃) and 25# mineral oil (-23℃). Thus, canola oil methyl ester was the best candidate as a low-viscosity vegetable oil–based dielectric. The low-viscosity fluid could extend the service life of transformers by its better cooling capacity compared with nature ester dielectrics.

Renewable Low-viscosity Dielectrics Based on Vegetable Oil Methyl Esters

Yu, Hui,Yu, Ping,Luo, Yunbai The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.2

Vegetable oil dielectrics have been used in transformers as green alternatives to mineral insulating oils for about twenty years, because of their advantages of non-toxic, biodegradability, and renewability. However, the viscosity of vegetable oils is more than 3 times of mineral oils, which means a poor heat dissipation capacity. To get low-viscosity dielectrics, transesterification and purification were performed to prepare vegetable oil methyl esters in this study. Electrical and physical properties were determined to investigate their potential as dielectrics. The results showed that the methyl ester products had good dielectric strengths, high water saturation and enough fire resistance. The viscosities (at $40^{\circ}C$) were 0.2 times less than FR3 fluid, and 0.7 times less than mineral oil, which indicated superior cooling capacity as we expected. With the assistance of 0.5 wt% pour point depressants, canola oil methyl ester exhibited the lowest pour point ($-26^{\circ}C$) among the products which was lower than FR3 fluid ($-21^{\circ}C$) and 25# mineral oil ($-23^{\circ}C$). Thus, canola oil methyl ester was the best candidate as a low-viscosity vegetable oil-based dielectric. The low-viscosity fluid could extend the service life of transformers by its better cooling capacity compared with nature ester dielectrics.

Decolorization of Aqueous Caprolactam Solution by Anion-exchange Resins

Yuan Zhen,Yu Ping,Luo Yunbai The Korean Fiber Society 2006 Fibers and polymers Vol.7 No.2

Caprolactam is the most important raw material for making Nylon 6 fibers and its quality directly determines the quality of Nylon. So it is necessary to study the techniques and methods to remove the colorful impurities from caprolactam. In this paper, the decolorization of caprolactam aqueous solution by anion exchange resins was studied and the decoloring abilities of five commercial resins were investigated. The regeneration of the resins was also studied, too. This study shows that the resin AMTX202 have excellent decoloring ability in the column experiment and that the decoloring efficiency is correlated with the volume of resins packed and is slightly affected by the flow rate and regenerating times. The fact that the resins can be regenerated and reused without affecting the efficiency of decolorization will decrease the cost of the treatment and operation in the industry. The adsorption of colored compounds with anion exchange resins in the packed columns seems to be technically feasible.

A novel membrane on pervaporation performance for dehydration of Caprolactam solution

Qin Li,Yanwen Lin,Tianrong Zhu,Yunbai Luo,Ping Yu 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.2

Konjac glucomannan (KGM) is a kind of polysaccharide with wide applications, except in pervaporation (PV). This article focuses on the new function of KGM and simultaneously improving a new dehydration process for e-Caprolactam (CPL). KGM was cross-linked with glutaraldehyde (GA) at proportions of 0.3,0.5, and 0.7 wt%. Cross-linked membranes were characterized by scanning electron microscope, Fourier transform-infrared, and X-ray diffraction to assess the membranes of morphology, intermolecular interactions, and observe the effects of cross-linking on crystallinity, respectively. Cross-linked KGM as the active layer of the composite membranes has the net matrix structure, and many characteristics improved compared with pure KGM. Data showed that KGM cross-linked with GA displayed good swelling and PV performance, and the composite membranes had superior separation performances in dehydrating the CPL solution. The highest separation factor could reach 3531. The study provided a new way for both KGM application and CPL dehydration.

Removal of NO from flue gas by wet scrubbing with NaClO2/(NH2)2CO solutions

Jinchao Wei,Ping Yu,Bo Cai,Houzhang Tan,Yunbai Luo 한국공업화학회 2009 Journal of Industrial and Engineering Chemistry Vol.15 No.1

The experiments were performed in a countercurrent packed column in a continuousmode to study the absorption of nitric oxide in sodium chlorite/urea solutions. Sodium chlorite mainly works as an agent to oxidize NO to NO2. A combined SO2/NO removal system was also tested. On the basis of high SO2 removal efficiency, the NO removal efficiencies under various experimental conditions were emphatically measured. Among the operating variables such as initial NaClO2 concentration, urea concentration, temperature and initial pH value, the pH value of the absorbing liquid was found to have a great impact on both NO removal efficiency and NO2 concentration. NO removal efficiency was increased with increasing NaClO2 concentration and temperature. Urea almost has no negative effect on NO removal efficiency, however it aids the abatement of NO2 greatly. The anions in the spent scrubbing liquor were analyzed by ion chromatography. 2009 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Lifetime Prediction and Aging Behaviors of Nitrile Rubber Under Operating Environment of Transformer

Yi-Hua Qian,Hong-zhao Xiao,Ming-hao Nie,Yao-hong Zhao,Yunbai Luo,Shu-ling Gong 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

Based on the actual operating environment of transformer, the aging tests of nitrile butadiene rubber (NBR) were conducted systematically under four conditions: in air, in transform oil, under compression in air and under compression in transform oil to studythe effect of high temperature, transform oil and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber and predict the lifetime. The effects of liquid media and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber were studied by using characterization methods such as IR spectrosc-opy, thermogravimetric measurements, Differential Scanning Calorimetry (DSC) measurements and mechanical property measurements. The changes in physical properties during the aging process were analyzed and compared. Different aging conditions yielded materials with different properties. Aging at 70°C under compression stress in oil, the change in elongation at break was lower than that aging in oil, but larger than that aging under compression in air. The compression set or elongation at break as evaluation indexes, 50% as critical value, the lifetime of NBR at 25°C was predicted and compared. When aging under compression in oil, the prediction lifetime was lower than in air and under compression in air, and in oil. It was clear that when predicting the service lifetime of NBR in oil sealing application, compression and media liquid should be involved simultaneously. Under compression in oil, compression set as the evaluation index, the prediction lifetime of NBR was shorter than that of elongation at break as the evaluation index. For the life prediction of NBR, we should take into account of the performance trends of NBR under actual operating conditions to select the appropriate evaluation index.