• Clean Technology
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• v.13 no.3
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• pp.188-194
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• 2007

In the present study, we developed a methodology to minimize a waste solution produced in the etching process. The condition for the optimization of the GRS process was studied on the basis of laboratory experiment and field test as well as pilot test. Through the study, we analyse the relation of the main process variables and the yield of the GRS process. The application of the new operation condition and the reactor internal modification results in 10% yield improvement in the GRS process and accordingly decreases a wasted solution.

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.837-845
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• 2017

A recirculating integrated system composed of a fluidized biofilter filled with waste-tire crumb media fixed with return sludge from wastewater treatment facility of D dyeing industrial center, and a UV/photocatalytic reactor packed with calcined $TiO_2$ coated-glass beads as photocatalyst-support, was constructed and was run to treat authentic textile-dyeing wastewater from D-dyeing industrial center, which was mixed with an alkaline polyester-weight-reducing wastewater and a wastewater from sizing process. As a result, its total removal efficiency(RE(tot)) of $COD_{cr}$ and colors were ca. 81% and 55%, respectively. The synergy effect of the recirculating integrated system to enhance total removal efficiency(RE(tot)) of $COD_{cr}$ and colors were evaluated at most ca. 7% and 3%, respectively. The fluidized biofilter and the UV/photocatalytic reactor were responsible for ca. 94% and 6% of the total $COD_{cr}$ removal efficiency, respectively, and were also responsible for ca. 86% and 14% of the total color-removal efficiency, respectively. Thus, the degree of the UV/photocatalytic reactor-unit process's contribution to RE(tot) of color, was about 2.4 times of that to RE(tot) of $COD_{cr}$. Therefore, the UV/photocatalytic reactor facilitated the more effective elimination of colors by breaking down the chemical bonds oriented from colors of dyes such as azo-bond, than $COD_{cr}$. In addition, the effect of the removal efficiency of each unit process(i.e., the fluidized biofilter or the UV/photocatalytic reactor) of the recirculating integrated system on RE(tot) of $COD_{cr}$ and colors, was analysed by establishing its model equation with an analytic correlation.

• KSBB Journal
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• v.5 no.4
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• pp.335-339
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• 1990

In order to develop economic processes for ethanol production from starch, a simultaneous saccharification and fermentation(SSF) process using Zymomonas mobilis and amyloglucosidase (AMG) was studied in semibatch modes using cell recycle. The cell recycle was carried out by adopting two different methods; microfiltration and settling. The cell recycle using microfiltration revealed higher productivity(5.4 g/l/h) than that using a settler(4.3 g/l/h). Taking the large-scale ethanol fermentation into account, the semibatch process using microfiltration system appeared most promising among others with respect to ethanol productivity, feasibility of scale-up and simplification of operation.

• KSBB Journal
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• v.11 no.3
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• pp.347-352
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• 1996

The enzyme deactivation in a membrane recycling system for the simultaneous saccharification and fermentation(SSF) was studied under various temperature and pressure. The optimum molecular weight cut off(MWCO) of the ultrafiltration membrane for recycling cellulase and ${\beta}$-glucosidase was 50,000. When the cellulase was recycled continuously through the membrane system, it was not deactivated. But the activity of ${\beta}$-glucosidase was decreased with an increase in operating temperature and transmembrane pressure. After 720 minutes at $42^{\circ}C$ and 24.8 psig , the activity of ${\beta}$-glucosidase was reduced by 35% of the initial activity. Such tendencies could be well explained by the results of highly induced shear at the fiber surface of membrane when temperature and transmembrane pressure became higher.

• Management & Information Systems Review
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• v.38 no.2
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• pp.67-81
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• 2019

In accordance with K-IFRS 1109, financial instruments are classified to amortized cost (AC), fair value through other comprehensive income (FVOCI) and fair value through profit or loss (FVPL). And disposal gains are prohibited to be recirculated for net income when FVOCI financial instruments would be sold in the future, so-called recirculation prohibition. This research investigates whether accumulated other comprehensive income of available-for sale financial assets(AFS) under K-IFRS 1039, could affect reclassified amounts to the FVPL securities from the AFS securities. Also, this study investigates the effects of the reported income on the reclassified FVPL, because CEOs are likely to try earnings management when net income is predicted to be less than target or is low, comparing other firms. As a result of empirical analysis, first, I find that accumulated other comprehensive income of the AFS has a positive impact on the reclassified FVPL. Second, level of reporting income has no significant impact on the reclassified FVPL. Third, interaction effects are significantly positive on the firms which have more other comprehensive income and less level of reported income. Fourth, the effects of the bank and securities are more distinct than those of the manufactures. This study is the first research to investigate earnings management through AFS at the timing of the first adoption of K-IFRS 1109. Empirical results of this study provide evidence of earnings management on the reclassification of FVPL which gives meaningful implications to regulators, academic researchers and auditors.

• Clean Technology
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• v.24 no.3
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• pp.233-238
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• 2018

Bio-oil is produced by the fast quenching of hot vapor produced by fast pyrolysis of biomass in an inert atmosphere. Nitrogen is used as carrier gas to control the concentration of oxygen less than 3%. The consumption of nitrogen should be increased with increasing process size, and leading to increasing of facility and operating costs due to nitrogen charge. The effects of the recycling of non-condensable gases on the fast pyrolysis, bio-oil yield and quality, and nitrogen consumption have systematically investigated to see the possibility of these results in fast pyrolysis process of palm residue.

• Clean Technology
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• v.9 no.1
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• pp.1-8
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• 2003

In order to implement clean technology to Petro-chemical process, simulation package of given process should exist. In this paper, reaction and recycling parts of a process are explained using EA process and MEK process respectively so as to explain how to make simulation package. Based on simulation package, several options are generated and feasibility tests are performed.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.383-389
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• 2003

AMBIDEXTER 원자력 시스템은 기존의 상용로와 다른 두 가지의 특징을 가지고 있다. 핵연료가 용융된 상태로 노심을 통과하면서 핵분열로 인해 발생한 열을 중간 열교환기를 거쳐 노심에으로 유입되고 일부는 우회하여 고온 화학 공정을 거쳐 핵연료 주입과 함께 노심으로 재순환 된다. 또한 노심이 특성이 다른 두 개의 격자를 기본으로 구성되어 핵분열 임계성을 유지하고 잠재 핵분열설 물질의 변환으로 인한 핵연료를 생성하여 핵분열물질 양을 일정하게 유지하여 핵적 자활성을 지니고 있다.(중략)

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.371-376
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• 2022

Liquefied natural gas undergoes a process of vaporization to be supplied as city gas, which generates about 800 kJ/kg of cold energy. Currently, all of this cold energy is being dumped into the sea, resulting in a very serious energy waste from the point of view of energy recycling. In this study, a seawater desalination process that can utilize the wasted cold energy was proposed, and this process was optimized to analyze the specific power consumption and economic feasibility. As a result, the specific energy consumption of the proposed process was calculated as -5.2kWh/m³, and the production cost of the pure water was 0.148 USD/m³, confirming that it is superior to any other process developed so far.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.89-95
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• 2009

Because of high contents of cellulose (~37 wt%) and hemicellulose (~17%), rice straw seems to be a potential lignocellulosic biomass for production of bioethanol. In this study, Ammonia Recycled Percolation (ARP) pretreatment of rice straw was extensively investigated. In particular, the experimental study included the effects of temperature, reaction time and concentration of ammonia on compositions and enzymatic digestibility of the resulting solid residues; the ranges of pretreatment conditions were, in turn, $150{\sim}190^{\circ}C$, 10~90 min and 0~20 wt%. Through ARP pretreatment, the lignin content was reduced by as high as ~84% while 20~80% of the hemicellulose was also solubilized. The solid residue resulted from the pretreatment with 15 wt% aqueous ammonia solution at $170^{\circ}C$ for 90 mim showed as high as ~90% of digestibility with 15FPU/g of glucan enzyme loading. Supplement of xylanese to cellulase led to a notable enhancement of digestibility, indicating a discernable inhibitory role of hemicellulose. Simultaneous Saccharification and Fermentation (SSF) and Simultaneous Saccharification and Co-Fermentation (SSCF) were performed to obtain ethanol productions of 13.8 g/L (corresponding to 81% yield) and 15 g/L (corresponding to 89% yield), respectively.