Editor’s Choice

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Editor’s Choice

NEWS & INFORMATION FOR CHEMICAL ENGINEERS, Vol. 39, No. 1, 2021 … 137 Korean Journal of Chemical Engineering,

Vol.37, No.12, 2085-2093, 2020

Modeling of the wet flue gas desulfurization system to utilize low-grade limestone

Lim JH, Choi YR, Kim GY, Kim JH

Abstract - Wet flue gas desulfurization was simulated to improve gypsum production using low-grade limestone. High-grade limestone with 94 wt% CaCO3 content is used for producing gypsum with 93 wt% purity, but owing to the resource depletion of high-grade limestone, low-grade limestone should be replaced as an alternative. However, lowgrade limestone with CaCO3

purity of less than 94% contains impurities such as MgCO3, Al2O3, and SiO2, which reduce gypsum purity. To resolve this issue, a process involving mixing of both low-grade and high-grade limestone was simulated to predict the quantity of low- grade limestone that could be utilized. Many reactions like limestone dissolution, SOX absorption, and crystallization were considered and were simulated by different models in Aspen plus. For process optimization, the following constraints were set:

93 wt% gypsum purity, 94% desulfurization efficiency, and 3,710 kg/h total limestone usage, which maximized the mass flow of low-grade limestone. The maximum blending quantity of low-grade limestone for 2,100 kg high-grade limestone that satisfied the constraints was ~1,610 kg.

Korean Journal of Chemical Engineering, Vol.37, No.12, 2094-2103, 2020

Experiment and multiphase CFD simulation of gas-solid flow in a CFB reactor at various operating conditions: Assessing the performance of 2D and 3D simulations

Upadhyay M, Seo MW, Naren PR, Park JH, Nguyen TDB, Rashid K, Lim HK

Abstract - Accurate prediction of gas-solid flow hydrodynamics is key for the design, optimization, and scale-up of a circulating fluidized bed (CFB) reactor. Computational fluid dynamics (CFD) simulation with two-dimensional (2D) domain has been routinely used, considering the computational costs involved in three-dimensional (3D) simulations. This work evaluated the prediction capability of 2D and 3D gas-solid flow simulation in the lab-scale CFB riser section. The difference between 2D and 3D CFD simulation predictions was assessed and discussed in detail, considering several flow variables (superficial gas velocity, solid circulation rate, and secondary air injection). The transient Eulerian- Eulerian multiphase model was used. CFD simulation results were validated through an in-house experiment. The comparison between the experimental data and both computational domains shows that the 3D simulation can accurately predict the axial solid holdup profile. The CFD simulation comparison considering several flow conditions clearly indicated the limitation of the 2D simulation to accurately predict key hydrodynamic features, such as high solid holdup near the riser exit and riser bottom dense region. The accuracy of 2D and 3D simulations was further assessed using root-mean-square error calculation. Results indicated that the 3D simulation predicts flow behavior with higher accuracy than the 2D simulation.

A comparative unit production cost prediction on isomerization by AlCl3 in comparison with HY(30) zeolite for the synthesis of tetrahydro tricyclopentadiene through a two-step process

Ryu CH, Cho YH, Jeong BH, Seo DU, Seong MJ, Lee KY

Abstract - In our previous study, we verified that a two-step process was superior to the one-pot process for the manufacture of THTCPD, assuming the pilot-scale production aspect of a comparative economic analysis by using an engineering estimation method to predict the unit manufacturing cost. Among the processes of the two-step process, our study was intended to focus on the isomerization to produce the final THTCPD products with outstanding physical properties including a specific gravity, a heat of combustion, a viscosity and a freezing point. Although HY(30) was used as an isomerization catalyst in the previous study, the catalytic activity of HY(30) did not surpass that of AlCl3 in terms of isomerization conversion, possibly due to lower exo-THTCPD selectivity by Bronsted acid sites of HY(30) than that by Lewis acid sites of AlCl3.

However, AlCl3 has some drawbacks of the impossibility for the catalyst regeneration during the manufacturing process due to the difficulty of the catalyst separation and recovery after isomerization, which causes environmental problems and biological toxicity issues due to its corrosivity. Therefore, our study concentrated on catalyst regeneration assuming the real production process in a pilot scale using AlCl3 in comparison with HY(30). Then, we investigated whether the isomerization catalyst

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Editor’s Choice

138 … NICE, 제39권 제1호, 2021

AlCl3 or HY(30) was more commercially favorable through a comparative unit production cost prediction applying an engineering estimation in this study. In conclusion, the unit production cost for AlCl3 was lower than that for HY(30) with the fresh catalyst. Reversely, unit production costs for HY(30) with increase in catalysts regeneration number (N) were lower than those for AlCl3 due to the drastic decrease in the unit material cost of HY(30) unlikely with that of AlCl3 due to its non- reusability.

Hybridized multi-objective optimization approach (HMODE) for lysine fed-batch fermentation process

Ani ZA, Gujarathi AM, Vakili-Nezhaad G

Abstract - A new hybrid multi-objective differential evolution (MODE) algorithm is proposed that combines the MODE algorithm for the global space search with a dynamical local search (DLS) method for the local space search. HMODE-DLS algorithm was validated using the tri-objective DTLZ7 test problem and the results were compared with MODE algorithm with respect to four performance metrics. In addition to HMODE-DLS, another three algorithms were used to solve two multi- objective optimization cases in an industrial lysine bioreactor at different feeding conditions. Case 1 considers maximizing lysine’s productivity and yield. While case 2 studies the maximization of productivity along with minimization of total operating time. In all cases, theoretical and industrial, HMODE-DLS showed a better performance with a better quality Pareto set of solutions. The Pareto front of case 1 found by HMODE-DLS was compared with a recent study trade-off, and the current non-dominated solutions values were found to be improved. This indicates that the lysine production process is enhanced. For case 2, the switching time from fed-batch to batch was found to be the key decision variable. Generally, these findings indicate the effectiveness of HMODE-DLS for the studied cases and its potential in solving real world complex problems.

Facile fabrication of copper oxide modified activated carbon composite for efficient CO

2

adsorption

Chen G, Wang F, Wang S, Ji C, Wang W, Dong J, Gao F

Abstract - Copper oxide modified activated carbon (CuO/AC) composites for the CO2 capture were synthesized via a facile assembly strategy associated with a direct solid-state heat dispersion process by introducing CuO into AC using Cu(NO3)2 as the copper source. The synthesized CuO/AC composites with various CuO contents were characterized by powder X-ray diffraction, scanning electron microscopy and nitrogen adsorption-desorption measurement, and the CO2 adsorption performance was investigated. The characterization results indicate that the Cu(NO3)2 species was well dispersed into the AC pore channels and then converted to a highly dispersed CuO after the activation process. The adsorption results reveal that the CO2 adsorption performance can be significantly improved by introducing CuO onto the AC surfaces, and the CuO(0.6)/AC composite with a CuO loading of 0.6mmol/g AC shows a high CO2 adsorption capacity and adsorption selectivity and displays an excellent reversibility. Additionally, the calculated adsorption heat values of CO2 on the CuO(0.6)/AC composite are in the range of 27.3 to 33.9 kJ/mol.

Morphological improvement of CH

3

NH

3

PbI

3

films using blended solvents for perovskite solar cells

Le N, Truong NTN, Le T, Pallaolu MR, Jeon HJ, Park CH

Abstract - Perovskite solar cells with the structure of glass/florine-doped tin oxide (FTO)/electron transfer layer (ETL)/

perovskite/hole transfer layer (HTL)/Ag were fabricated. The effects of blending solvents and thermal annealing on the surface morphology, structural, and optical properties of perovskite (CH3NH3PbI3) active layer were investigated. The active layer was optimized by adding 2-butanol (2-BTA) as an eco-friendly solvent into methyl ammonium iodide (MAI) solution used for spin coating on PbI2/(dimethylformamide (DMF)+dimethyl sulfoxide (DMSO)) film in the second step. The resulting morphology of CH3NH3PbI3 films was smooth and pinholes in the films were also reduced without change in the structure.

The effects of thermal annealing on the surface morphology and structural properties of active layer were also studied. The fabricated device for the optimized condition showed the maximum power conversion efficiency (PCE) of ~8.6%.

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Editor’s Choice

NEWS & INFORMATION FOR CHEMICAL ENGINEERS, Vol. 39, No. 1, 2021 … 139 Korean Chemical Engineering Research,

Vol.59, No.1, 21-34, 2021

Phthalate계 환경호르몬 제거를 위한 Lactococcus lactis를 함유한 Chitosan Nanoparticles의 제조

Fabrication of Chitosan Nanoparticles with Lactococcus lactis for the Removal of Phthalate Endocrine Hormone

윤희수, 강익중

Abstract - 본 연구에서는 Chitosan nanoparticles (CNPs) 와 Lactococcus lactis (L. lac.) 를 흡착제로 사용하여 phthalates의 흡착 실험을 진행하였다. CNPs는 Tripolyphospate (TPP)와의 가교 결합을 통하여 제조되었으며, 제조과정 중에 L. lac.의 도입을 통하여 L. lac.-CNPs를 제조하였다. 모든 흡착제는 Fourier transform infrared spectroscopy (FTIR)을 사용하여 특성을 측정하여 다양한 작용기의 존재를 확인하였다. Adsorption isotherm 과 adsorption kinetic 을 통하여 CNPs, L. lac.

및 L. lac.-CNPs 의 흡착 거동 및 메커니즘을 확인하였다. 모든 입자에 대하여 DBP 및 DEP 의 흡착 거동은 Langmuir adsorption isotherm model 보다는 Freundlich adsorption isotherm model 에 적합하였으며, 이는 입자의 표면이 이질적 (heterogeneous) 라는 것을 의미한다. 흡착 메커니즘은 Pseudo-1st-order model 보다는 Pseudo-2nd-order model 에 적합하였으며, 이는 DBP 및 DEP 의 흡착이 입자 표면의 다양한 작용기들에 의하여 물리적 흡착보다는 정전기적 인력과 수소 결합 등에 의한 화학적 흡착이 지배적임을 나타낸다. 최종적으로, 쉽고 빠른 방법으로 CNPs 및 L. lac-CNPs 의 제조가 가능하며, 유기성 오염 물질을 효과적으로 제거할 수 있는 저비용의 흡착제로서 사용할 수 있음을 확인하였다.

Korean Chemical Engineering Research, Vol.59, No.1, 77-84, 2021

등온 냉각액을 활용한 plug flow reactor 내의 과열점 제어를 위한 제어모델 개발

Control of Hot Spots in Plug Flow Reactors Using Constant-temperature Coolant

유진욱, 김연수, 이종민

Abstract - Plug flow reactor (PFR) 내의 과열점(hot spot) 온도를 조절하는 것은 생성물의 수득률 및 순도, 안전성 측면에서 중요하다. 본 연구에서는 더 현실에 가깝게 모델링 하기 위하여 PFR 내부의 냉각액 온도를 상태변수로 설정하고 방사 방향의 열 및 물질전달을 고려하였다. 모델은 반응물의 농도 및 온도와 냉각액의 온도 총 3개의 상태변수로 이루어져 있으며, 등온 냉각액의 유량을 조작변수로 가진다. 본 연구에서는 방사 방향의 열 및 물질전달을 고려한 제어식이 그렇지 않은 제어식보다 과열점의 온도를 set point 부근으로 더 효과적으로 유지한다는 것을 보였다.

본 연구에서 제안한 제어식은 냉각액의 온도가 반응물 온도의 약 0.7배 부근일 때 St가 1.3 이상이고 Ac/A가 2.0 이하인 조건에서 강건성을 유지하였다. 이 조건에서 반응기로 유입되는 반응물의 온도가 5% 범위에서 바뀔 때 본 연구에서 제안된 제안식을 이용하면 과열점의 온도를 set point의 1% 이내로 유지할 수 있다.

Korean Chemical Engineering Research, Vol.59, No.1, 100-105, 2021

PDMS 블레이드 코팅법을 이용한 종이-기반 바이오센서칩 제작

Fabrication of Paper-based Biosensor Chip Using Polydimethylsiloxane Blade Coating Method

정헌호, 박차미

Abstract - 본 연구는 적은 비용으로 분석 장치 없이 질병 진단 및 경과를 모니터링할 수 있는 종이-기반 분석 장치(paper-based analytical device, PAD)를 제작하기 위해 polydimethylsiloxane (PDMS) 블레이드 코팅 방법을 제안하였다. PAD 디자인은 레이저 커팅 기술로 쉽게 몰드에 적용할 수 있으며, 제작된 몰드로 블레이드 코팅을 수행하여 완전한 소수성 장벽 형성에 필요한 조건을 확립하였다. 코팅 조건인 잉크의 두께와 종이와의 접촉시간에 따라 PDMS 소수성 장벽의 구조와 친수성 채널의 크기 변화를 분석하여 안정적으로 소수성 장벽을 형성할 수 있는 조건을 최적화하였다. 최적화된 방법을 바탕으로 PAD를 제작하여 특별한 분석기기 없이 단백질, 당, 메탈이온을 검출하여 바이오센서에 응용가능함을 증명하였다.