• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.4
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• pp.313-318
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• 2006

A two-stage process of nanofiltration and water-splitting electrodialysis was investigated for lactic acid recovery from fermentation broth. In this process, sodium lactate is isolated from fermentation broth in the first stage of nanofiltration by using an NTR-729HF membrane, and then is converted to lactic acid in the second stage by water-splitting electrodialysis. To determine the optimal operating conditions for nanofiltration, the effects of pressure, lactate concentration, pH, and known added impurities were studied. Lactate rejection was less than 5%, magnesium rejection approximated 45%, and calcium rejection was at 40%. In subsequent water-splitting electrodialysis, both the sodium lactate conversion to lactic acid and sodium hydroxide recovery, were about 95%, with a power requirement of $0.9{\sim}1.0\; kWh$ per kg of lactate.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.753-761
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• 2016

Liquid-liquid extraction (LLE) can be used for the recovery of acetic acid from black liquor prior to bioethanol fermentation. Recovery of value-added chemicals such as acetic-, formic- and lactic acid using LLE from Kraft black liquor was studied. Acetic acid and formic acid have been reported to be strong inhibitors in fermentation. The study elucidates the effect of three reaction parameters: pH (0.5~3.5), temperature ($25{\sim}65^{\circ}C$), and reaction time (24~48 min). Extraction performance using tri-n-octylphosphine oxide as the extractant was evaluated. The maximum acetic acid concentration achieved from hydrolyzates was 69.87% at $25^{\circ}C$, pH= 0.5, and 36 min. Factorial design was used to study the effects of pH, temperature, and reaction time on the maximum inhibitor extraction yield after LLE. The maximum potential extraction yield of acetic acid was 70.4% at $25.8^{\circ}C$, pH=0.6 and 37.2 min residence time.

• Journal of the Korean Institute of Gas
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• v.15 no.1
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• pp.40-45
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• 2011

During process operations, overpressure can be caused by operator's error or malfunction of the device. To prevent this overpressure, gas was released through blowdown system. Because most of released gases are the hydrocarbon mixture and have flammable and toxic properties, the gas is released after burning in flare stack. The increase of scale and complexity of plant requires higher or additional flare stacks. This study tried to solve this problem through flare gas recovery system.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.229-233
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• 2016

In this study, an efficient ultrasound-assisted liquid-liquid extraction process was developed for recovering of paclitaxel from plant cell cultures. The optimal ultrasonic power and operating time were 250 W and 15 min at fixed ratio of bottom phase, methylene chloride to top phase, MeOH (25%, v/v). Under the optimal conditions developed in the present method, most of the paclitaxel (~92%) was recovered from crude extract by a single extraction step. Due to the synergistic effect of ultrasound by the addition of inorganic salt, an appropriate inorganic salt concentration and the ultrasonic power were found to be required for the effective recovery of paclitaxel using ultrasound-assisted liquid-liquid extraction.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.266-271
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• 2005

This paper studied succinic acid recovery from organic acid mixture by using mono-polar membrane electrodialysis. Current efficiency, solute recovery efficiency, energy consumption, and separation factor were measured at various pHs and concentration ratios. The separation factor of succinic acid could be interpreted in terms of ionization degree, molecular weight, ionic conductance, average charge, and initial feed composition.

• Membrane and Water Treatment
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• v.2 no.4
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• pp.267-279
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• 2011

At steady state, the simultaneous transport of sulphuric acid and nickel sulphate through an anion-exchange membrane Neosepta-AFN (Astom Corporation, Tokyo, Japan) was investigated in a two-compartment counter-current dialyzer with single passes. The transport was quantified by the recovery yield of acid, rejection of salt and four phenomenological coefficients, which were correlated with the acid and salt concentrations in the feed. The phenomenological coefficients were determined by the numerical integration of the basic differential equations describing the concentration profiles of the components in the dialyzer. This integration was combined with an optimizing procedure. The experiments proved that the acid recovery yield is in the limits from 63 to 91 %, while salt rejection is in the limits from 79 to 97 % in the dependence on the volumetric liquid flow rate and composition of the feed.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.109-122
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• 2018

This work highlights extraction and removal of Lignosulfonate using sunflower oil-Tri-n-octylamine (TOA) system in bulk liquid membrane transport. Maximum extraction and recovery percentages of 92.4% and 75.2% were achieved. Optimum manifold operating conditions were: 4 vol.% TOA, $2{\pm}0.1$ feed phase pH, 300 rpm stirring speed, at $40^{\circ}C$ with 0.2 (M) $Na_2SO_4$ solution. 1:2 (organic/aqueous) and 1:1 (aqueous/aqueous) phase ratios produced best results. Extraction (36.85 kJ/mol) was found to be intermediate controlled and stripping (54.79 kJ/mol) was chemical reaction controlled. Kinetic estimation of data with higher rate constants for stripping vis-${\grave{a}}$-vis extraction showed latter to be rate determining.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.135-139
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• 2016

We developed a liquid-liquid extraction method using an inorganic salt to dramatically improve the recovery efficiency of the anticancer agent paclitaxel from plant cell cultures. As a result of liquid-liquid extraction using a diverse types of inorganic salt (NaCl, KCl, $K_2HPO_4$, $NaH_2PO_4$, $NaH_2PO_4{\cdot}2H_2O$), NaCl gave the highest yield (~96%) and lowest partition coefficient (0.053) of paclitaxel. The optimal NaCl/solvent ratio, methylene chloride/MeOH ratio, and pure paclitaxel content for liquid-liquid extraction using NaCl were 1% (w/v), 26% (v/v), and 0.066% (w/v), respectively. Under the optimal conditions developed in the present method, most of the paclitaxel (~96%) was recovered from biomass by a single extraction step. In addition, this method facilitated 3-fold higher recovery efficiency of paclitaxel in a shorter extraction number than the conventional liquid-liquid extraction method.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.5
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• pp.425-431
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• 2006

The development of fermentation conditions for the production of C595 diabody fragment (dbFv) in E. coli HB2151 clone has been explored. Investigations were carried out to study the effect of carbon supplements over the expression period, the comparison of C595 dbfv production in synthetic and complex media, the influence of acetic acid upon antibody production, and comparison of one-stage and two-stage processes operated at batch or fed-batch modes in bioreactor. Yeast extract supplied during expression yielded more antibody fragment than any other carbon supply. The synthetic medium presented higher specific productivity (0.066 mg dbFv $g^{-1}$ dry cell weight) when compared to the complex medium (0.044 mg dbFv $g^{-1}$ DCW). The comparison of fermentation strategies demonstrated that (1) one-stage fed-batch fermentation performed higher C595 dbFv production than that operated in batch mode which was significantly affected by acetate concentration; (2) a two-stage batch operation could enhance C595 dbFv production. It was found that a concentration of 12.3 mg $L^{-1}$ broth of C595 dbFv and a cell concentration of 10.8g $L^{-1}$ broth were achieved at the end of two-stage operation in 5-L fermentation.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.54-59
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• 2017

A study for process design to curtail the utility consumption during residual styrene monomer recovery in an ABS polymerization process was carried out. Among different techniques for residual monomer recovery, the steam stripping is dominantly employed in industries. The existing process, however, consumes a large amount of utility (steam and cooling water), and this study focused on the design of a new process that can substantially spare the utility consumption. A new process was configured to utilize the latent heat of the stripping steam, which is condensed with the monomer using cooling water after exiting the stripper. The condenser was modified to use vacuum state water as coolant and to generate vacuum state steam using the latent heat of the stripping steam. The steam is injected to the stripper as the stripping steam after upgrading using a compressor. Through this modification, consumption of steam and also cooling water could be significantly reduced at some expense of electricity for compressor operation.