• Journal of Energy Engineering
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• v.12 no.4
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• pp.302-308
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• 2003

The peformence tests of zinc-based desulfurization sorbents using the yellow earth as support for the hot gas clean up were carried out. The zinc-based sorbent with 25 wt％ yellow earth was prepared, and their properties such as the reaction rate, the sulfur capacity and the attrition resistance, were investigated. The reactivity tests for hot gas desulfurization was performed at middle temperatures (sulfidation/regeneration：480$^{\circ}C$/580$^{\circ}C$). During multi-cyclic desulfurization, the deactivation of zinc-based sorbent was decreased by the addition of yellow earth, and their efficiency was enhanced. The ZnO/yellow earth sorbent had high reactivity, good regenerability, long-term durability (about 19 gS/100 g sorbent for 10-cycles) and high attrition resistance (AI=19.1％). It was concluded that the peroperties of zinc-based sorbent were improved by metal oxides (Fe$_2$O$_3$, Na$_2$O, MnO$_2$, etc) in the yellow earth. From these results, it was confirmed that the desulfurization properties of zinc-based sorbents at middle temperatures could be improved by the yellow earth using as support.

• Journal of Energy Engineering
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• v.12 no.1
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• pp.1-10
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• 2003

Pressurized fluidized bed combustion unit is operated at pressures of 1~1.5 MPa with combustion temperatures of 850~87$0^{\circ}C$. The pressurized coal combustion system heats steam, in conventional heat transfer tubing, and produces a hot gas supplied to a gas turbine. Gas cleaning is a vital aspect of the system, as is the ability of the turbine to cope with some residual solids. The need to pressurize the feed coal, limestone and combustion air, and to depressurize the flue gases and the ash removal system introduces some significant operating complications. The proportion of power coming from the steam : gas turbines is approximately 80:20%. Pressurized fluidized bed combustion and generation by the combined cycle route involves unique control considerations, as the combustor and gas turbine have to be properly matched through the whole operating range. The gas turbines are rather special, in that the maximum gas temperature available from the FBC is limited by ash fusion characteristics. As no ash softening should take place, the maximum gas temperature is around 90$0^{\circ}C$. As a result a high pressure ratio gas turbine with compression intercooling is used. This is to offset the effects of the relatively low temperature at the turbine inlet.

• Journal of Energy Engineering
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• v.13 no.1
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• pp.75-81
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• 2004

ZZFCa sorbents for hot gas desulfurization in IGCC were prepared by adding calcium oxide to ZZF sorbent in order to improve its attrition resistance in this study. ASTM attrition test for the sorbent was performed at several different weight percentages of CaO to investigate the attrition characteristics of ZBFCa sorbents as a function of CaO content. Attrition index of ZZF without CaO was 28.3% and its collected attrition index was 10.8％. ZZFCa-3 containing 3 wt% CaO showed the lowest attrition index (AI=17.3％, CAI=8.8％) in the test. From the results of SEM morphologies and particle size distribution measurements, ZZFCa-3 maintained a fine shape and a desirable average particle size even after attrition test. In the experiments of sulfidation/regeneration for ZZFCa-3 sorbent concentration of hydrogen sulfide in coal gas was lowered from 10000 ppm to below 1 ppm. Sulfur removing capacity was about 28.8 g S/100 g sorbent. Neither formation of CaSO$_4$ was observed in XRD measurement nor SO$_2$ slippage was observed during sulfidation process.

• Korean Journal of Food Science and Technology
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• v.49 no.6
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• pp.584-590
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• 2017

Effects of bleaching and deodorization on the quality of imported palm and canola oils were evaluated. Imported palm oil and deacidified canola oil were bleached with acid clay, followed by deodorization. Oxidation-related quality was evaluated by determining fatty acid composition by GC, acid and peroxide values, induction period by Rancimat, and off-flavor compounds by GC-MS. Tocopherols and benzo(a)pyrene were analyzed by HPLC. Acid and peroxide values were decreased by bleaching and deodorization, and tocopherol content was decreased to 60-70% (p<0.05). Aldehydes were major off-flavor compound class of imported oils, most of which were removed after deodorization. No significant change was observed in benzo(a)pyrene content (${\sim}0.4{\mu}g/kg$) of both oils by bleaching and deodorization (p>0.05). The oxidation-related quality of palm and canola oils was more improved after industrial bleaching than by deodorization. These results suggest that a careful control of bleaching during domestic refining can improve the quality of palm and canola oils.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.11a
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• pp.146-148
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• 2003

Bayer 공정은 가성소다를 이용하여 보오크사이트로부터 수산화알루미늄을 추출하는 공정이다. 그러나 보오크사이트 추출 후 1차 침전공정에서 반응한 보오크사이트 잔사는 침전시킴으로써 깨끗한 공정액을 분리하는 데 이때 침전되지 못한 다량의 분산성 고형물이 공정액 중에 존재하게 되는데 이를 분산성 보오크사이트(레드머드) 미립자라하며 보통 80-100mg/$\ell$의 농도를 나타낸다. 그러므로 이를 제거하기 위해 다음 공정인 입상여과필터 공정을 사용하는데 이때 필터링 효율증대를 위해 보조제로써 다량의 소석회(Ca(OH)$_2$)를 투여하여 공정액 중의 고형물을 농도를 8-100mg/$\ell$에서 5mg/$\ell$로 낮추는 공정을 사용하고 있다. 특히 국내 수산화알루미능 제조회사일 KC(주)의 경우 소석회 사용량이 일 10톤, 년간 약 3,600톤을 사용함으로써 소석회의 사용량에 따라 같은 량의 슬러지가 발생되게 된다. 따라서 여과후 발생되는 슬러지의 처리비용 문제(연간 9천만원)와 소석회의 미립자에 의한 공정액의 2차 오염과 제품 품질 저하(quality claim) 및 소석회 사용량에 따른 연간 원료비(연간 3억원) 등의 상당한 문제점을 나타내고 있는 실정이다. 아울러 최근 고품위 수산화알루미늄의 공급 요구에 따라 여과시 정제기준이 점차 낮아져 이제는 1mg/$\ell$ 이하를 유지하여야 하는 근본적인 문제에 봉착해있는 실정이다. 그러므로 본 연구에서는 소석회를 사용하는 입상여과법을 대체하기 위한 신공정개발을 추진하였으며, 그동안 카트리지여과법 등의 다양한 실험 결과로부터 최근 필터 보조제를 첨가하지 않는 물리적 여과방법인 세라믹 막 여과법의 적용 가능성을 확인하고 친환경공정인 세라믹 막 여과 실용화 공정 기술을 개발하였다. 세라믹 막 여과 법은 여과 보조제를 사용하지 않으므로 2차적인 슬러지 발생등의 환경문제를 발생하지 않으며, 공정액에 첨가제를 투입하지 않으므로 순환형 친환경공정으로 각광받을 수 있다. 본 연구에서는 고온, 고농도의 NaOH 수용액의 처리에 적합한 막소재와 발생될 수 있는 제반 문제점 등을 파악하였고, 장기간의 실험을 거쳐 최적 투과 압력(Trans membrane pressue), 세정 조건 및 주기, 막재질에 있어서 보강하여야 할 Point, 최적 운전 조건들을 토출해 내었고, 향후 실제 Plant에 적용할 계획이다.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.593-599
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• 1996

The effects of high pressure on alliinase and on flavor of garlic (Alliiium sativum L.) were investigated. After pressurized at 150 MPa, 300 MPa, and 500 MPa for 10 min, the activities of purified alliinase were reduced approximately 30%, 80%, and 100%, respectively, while the enzyme activities of pressurized garlic cloves were reduced 0%, 7%, and 100%, respectively. This indicated that the intact garlic has a protective effect against pressure-inactivation of alliinase. Alliinase was more effectively inactivated when high pressure treatment was carried out at high ($>40^{\circ}C$) or low temperature ($>10^{\circ}C$) than ambient temperature. Pressure treated garlic at 500 MPa had little pungency and sulfuryl odor compared to raw garlic indicating that high-pressure processing can be used to produce garlic without pungent flavor.

• Microbiology and Biotechnology Letters
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• v.38 no.2
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• pp.158-162
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• 2010

The gene encoding N-terminally truncated Tod polymerase ($\Delta$Tod polymerase) from Thermus thermophilus HJ6 was expressed in Escherichia coli under the control of the lambda pR and pL tandem promoters on the expression vector pJLA503. The N-terminal domain (250 amino acids) of Tod polymerase was removed without significant effect on enzyme activity and stability, while no 5'$\rightarrow$3' exonuclease activity was detected. The $\Delta$Tod polymerase was verified to possess very efficient reverse transcriptase (RT) activity in the presence of $MgCl_2$. The cDNA can also be amplified in the polymerase chain reaction (PCR) with this mutant enzyme. The $\Delta$Tod polymerase was exhibited higher activity than the Taq polymerase in a one-step RT-PCR.

• Resources Recycling
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• v.12 no.3
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• pp.25-30
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• 2003

The synthesis of SiC used for the parts of the gas turbine and the heat exchanger, was carried out. In this study, wire cutting slurry of silicon wafer and the graphite rod of spent zinc-carbon battery were applied to the starting materials for the synthesis. The powders of Si or Si+SiC were obtained from the waste material by filtration, gravity separation and magnetic separation. Graphite powder was produced by dismantling, grinding and gravity separation from spent zinc-carbon battery. The synthesis of SiC could be completed from the mixture powders of Si and C or Si+SiC and C at the condition of equivalent ratio of Si and C, atmosphere of Ar or vacuum, temperature of above 1$600^{\circ}C$ and 2 hours reactions. The purity of synthesized Si-C was above 99%.

• Journal of Sericultural and Entomological Science
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• v.43 no.2
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• pp.109-115
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• 2001

Silk sericin protein was extracted by treatment with enzyme or NaOH solution from raw silk and culled-cocoon shell. The extracted sericin was characterized and examined the functional properties as well as subjective properties for its use as a soap and a body cleaner. The optimum extraction conditions on specimen are NaOH (0.02 wt.%) or enzyme, Flavourzyme 3% under N2 gas. Molecular weights of sericin was decreased by treatment with enzyme, Actinase, from 10,000-30,000 to 2,700-4,200. Sericin showed important bioactive properties, for instance, lowering effect on blood glucose and alcohol. Subjective test of sericin soap and body cleaner showed superior in washability, foamability, and skin hydration, etc., to commercial soap and body cleaner. Therefore, it is thought that silk sericin can be expected as the source of bioactive and skin-compatible materials.

• Resources Recycling
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• v.31 no.3
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• pp.73-80
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• 2022

Reduction smelting of spent lithium-ion batteries at high temperature produces metallic alloys. Following solvent extraction of the leaching solutions of these metallic alloys with either sulfuric or hydrochloric acid, the raffinate is found to contain Ni(II), Co(II), Mn(II), and Si(IV). In this study, two cationic exchange resins (Diphonix and P204) were employed to investigate the loading behavior of these ions from synthetic sulfate and chloride solutions. Experimental results showed that Ni(II), Co(II), and Mn(II) could be selectively loaded onto the Diphonix resin from a sulfate solution of pH 3.0. With a chloride solution of pH 6.0, Mn(II) was selectively loaded onto the P204 resin, leaving Ni(II) and Si(IV) in the effluent. Elution experiments with H₂SO₄ and/or HCl resulted in the complete recovery of metal ions from the loaded resin.