The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Yongwon Seo - One of the best experts on this subject based on the ideXlab platform.
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Formation and dissociation behaviors of SF6 hydrates in the presence of a surfactant and an Antifoaming Agent for hydrate-based greenhouse gas (SF6) separation
Chemical Engineering Journal, 2020Co-Authors: Yongwon SeoAbstract:Abstract Sulfur hexafluoride (SF6), the most potent greenhouse gas, should be separated from gas mixtures for recycling and for mitigation of global warming. In this study, the formation and dissociation behaviors of SF6 hydrates in the presence of a surfactant (sodium dodecyl sulfate, SDS) and an Antifoaming Agent (antifoam A concentrate, AAC) were investigated, with a primary focus on kinetic, spectroscopic, and morphological analyses for hydrate-based SF6 separation. The optimum concentrations of SDS and AAC for SF6 hydrates were found to be 250 ppm and 1,500 ppm, respectively. The structure of SF6 hydrates in the presence of SDS and AAC was identified as structure II, indicating that SDS and AAC had no impact on hydrate structure. The formation behaviors of SF6 hydrates were thoroughly examined through gas uptake measurements, visual observation, and in-situ Raman spectroscopy. The addition of SDS 250 ppm significantly accelerated the formation rate of SF6 hydrate and the additional injection of AAC did not inhibit the promoting effect of SDS. Visual observation, temperature profiles, and volume of retrieved gas during the dissociation of SF6 hydrates clearly demonstrated that SDS also had a promoting effect on SF6 hydrate dissociation and its effect was slightly diminished with the addition of AAC, although AAC showed a powerful defoaming effect during the dissociation of SF6 hydrates. The experimental results obtained in this study will be very useful for accelerating the formation rate of SF6 hydrates using SDS and for solving the foaming problem using AAC in the design and operation of the gas hydrate-based SF6 separation process.
Flavio Vázquez - One of the best experts on this subject based on the ideXlab platform.
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Study of the thermal stability of jojoba oil used as Antifoaming Agent in petroleum industry
Journal of Thermal Analysis and Calorimetry, 2016Co-Authors: Enrique Cevada, César Flores, Alfonso López, Fernando Álvarez, Flavio VázquezAbstract:Jojoba oil is a naturally occurring vegetal oil, used widely in cosmetic, pharmaceutical, dietetic foods, animal feeding and as a constituent of bio-diesel. In addition, its use in petroleum conditioning has been reported. In this research, four samples of jojoba oil were carefully characterized and their performance as Antifoaming Agents in light crude oil was studied. A derivative of Simmondsia chinensis was characterized by different techniques such as Fourier transform infrared spectroscopy, nuclear magnetic resonance and size exclusion chromatography. Thermal degradation of jojoba oil was followed by thermogravimetry analysis (TG), differential scanning calorimetry and, primarily, TG coupled to Fourier Transform infrared spectroscopy. Furthermore, a molecular dynamic simulation was carried out in order to investigate the behavior of this compound when subject to thermal degradation. Assessments in light crude oil determined said vegetal oil to have a good performance level as a foam inhibitor at a low temperature (20 °C). Its high degree of thermal stability was also established through calorimetric techniques.
Takenori Tanaka - One of the best experts on this subject based on the ideXlab platform.
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reduction in operator supervision time using a modified malfunction detection system with fuzzy inference in an industrial scale fermentation of alkaline cellulase
Journal of Bioscience and Bioengineering, 2001Co-Authors: Takenori Tanaka, Masahito TayaAbstract:Abstract A malfunction detection system based on fuzzy inference, in which a fermentation process is categorized into three states (normal, intermediate and abnormal) according to the computation of malfunction degree, was modified to reduce the supervision tasks required for an industrial-scale production of alkaline cellulase. The time lag of the culture, τ, was determined from the difference in the cumulated amount of CO 2 evolved between the actual and standard values. By employing τ, the deviations of the actual values of process data (pH of broth and the amount of Antifoaming Agent supplied) from the standard values could be compensated for in terms of a delayed or forward effect in fermentation time. In the detection tests conducted for a series of 200 runs using the modified method, two runs and a single run were categorized as belonging to the abnormal and intermediate states, respectively, and all of the other runs were recognized to be in a normal state. As a result, the total supervision time for operators was reduced by the modification.
Jing Bai - One of the best experts on this subject based on the ideXlab platform.
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Effect of ionic strength on the foam fractionation of BSA with existence of Antifoaming Agent
Chemical Engineering and Processing: Process Intensification, 2010Co-Authors: Fang Zhang, Hao Yin, Jing BaiAbstract:Abstract Foam fractionation is an economical and effective technology for protein concentration and separation. However, the presence of Antifoaming Agent in the fermentation broth restricts the application of this technology. In this paper surfactant-assisted foam process was conducted with a mimic system using bovine serum albumin (BSA) as target protein, polyoxypropylene polyoxyethylene glylerin ether (PGE) as Antifoaming Agent and cetyltrimethyl ammonium bromide (CTAB) as surfactant, putting emphasis on study of the effect of ionic strength on the separation process. The experimental results showed that with ionic strength increasing, the mixed-system foaming ability gradually increased. Under the conditions of CBSA 100 mg/L, CCTAB 20 mg/L, CPGE 8 mg/L and pH 7.4, feed liquid 250 mL, air flow rate 100 mL/min at 25 °C, the maximum enrichment ratio of BSA reached 27 when the ionic strength was 0.0500 mol/kg and the maximum recovery of BSA reached 80.5% when the ionic strength was 0.1696 mol/kg. Furthermore, K+ had better separate efficiency than Na+ under the same ionic strength.
Dinesh O. Shah - One of the best experts on this subject based on the ideXlab platform.
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Effect of Antifoaming Agents on the Micellar Stability and Foamability of Sodium Dodecyl Sulfate Solutions
Langmuir, 1999Co-Authors: B. K. Jha, And A. Patist, Dinesh O. ShahAbstract:The effect of Antifoaming Agents on the foamability of sodium dodecyl sulfate (SDS) solutions was investigated and correlated with their effect on the micellar relaxation time τ2. The slow micellar relaxation time τ2 of SDS micelles, which is directly related to micellar stability, was determined by the pressure-jump method in the presence of the Antifoaming Agents 2-ethylhexanol (EH), tributyl phosphate (TBP), and tetrabutylammonium chloride (TBAC). Pressure-jump studies show an increase in τ2 up to a critical concentration of the Antifoaming Agent. Further addition of Antifoaming Agent results in a decrease in τ2. Such behavior has been observed for all three Antifoaming additives. The increase in τ2 is attributed to the stabilization of SDS micelles by the additives, which essentially minimizes the repulsion between headgroups of SDS molecules at the micellar surface or at the interface. The Antifoaming efficiency of EH, TBP, and TBAC was tested by simply generating the foam by the shaking method. The ...