Antifoam Research Articles

친환경 콘크리트 개발을 위한 고분자 화합물의 적용에 관한 연구

본 연구는 수용성 폴리머의 일종인 폴리비닐아세테이트(Polyvinyl Acetate, 이하 PVAc)를 사용한 폴리머 시멘트 모르타르와 콘크리트의 특성에 관한 평가를 통하여 친환경 콘크리트 개발을 위한 기초자료를 획득하는 것이다. 이를 위해 PVAc를 혼입하지 않은 시멘트 모르타르 및 콘크리트와 결합재 대비 3%, 6%, 9%, 12%의 PVAc를 각각 혼입한 폴리머 시멘트 모르타르 및 콘크리트와의 비교분석을 통한 물리적 특성을 평가하였으며, 폴리머 혼입에 따라 늘어나는 공기량을 제어하기 위해 소포제를 첨가하여 PVAc 콘크리트의 특성을 평가하였다. 그 결과 PVAc가 혼입된 폴리머 시멘트 모르타르의 경우 압축강도는 낮아지나 휨강도와 건조수축의 성능이 향상되는 것으로 나타났으며, 콘크리트의 경우 혼입율이 6%일 때가 압축강도, 인장강도, 휨강도 및 탄성계수가 높아지는 것을 확인할 수 있었다. The objective of this paper is to obtain the basic data in order to develop an eco-friendly concrete through evaluation on the properties of polymer cement mortar and concrete using PVAc (Polyvinyl Acetate), as a kind of water-soluble polymer. For this purpose, the physical properties of cement mortar and concrete which does not contain the PVAc as the control batch were compared and analyzed with those using the PVAc. And then, the replacement amount of the PVAc was 3%, 6%, 9% and 12% by binder, respectively. And also, the properties of concrete using the PVAc were evaluated, by adding an antifoaming agent in order to control the air contents increasing with an increase of amount of polymer usage. As a result, in the case of polymer cement mortar using the PVAc, it presented that the compressive strength reduced, while the performance of flexural strength and drying shrinkage increased. When the replacement of the PVAc was 6% within concrete, the compressive, tensile, flexural strength and elastic modulus were increased.

Comparison of Photocatalytic Hydrogen Production from Glycerol and Crude Glycerol Obtained from Biodiesel Processing

Photocatalytic hydrogen generation from aqueous solutions of glycerol and crude glycerol (byproduct of biodiesel manufacturing) were compared using Pt/TiO2 and CuOx/TiO2 catalysts. Glycerol solutions generated more H2 than crude glycerol solutions, with the H2 generation rate approximately 2.5 times higher for Pt/TiO2 and approximately 4 times higher for CuOx/TiO2. Pt/TiO2 produced more H2 than CuOx/TiO2, with a ratio nearly 2.5 times higher for glycerol and nearly 3.5 times higher for crude glycerol. Ion exchange of crude glycerol solutions to replace Na+ with Li+ or K+ had little impact on reactions with CuOx/TiO2 whereas ion exchange with Li+ moderately reduced reaction rates with Pt/TiO2. An anti-foam agent reduced foaming problems associated with higher concentrations of crude glycerol but itself degraded. The addition of 0.4 mM NaH2PO4 reduced the H2 generation rate by nearly 60 % whereas the presence of 0.4 mM NaCl, 0.4 mM NaNO3 or 0.2 mM Na2SO4 reduced the H2 generation rate by only 10–20 % over the course of the reaction.

Comparative review of foam formation in biogas plants and ruminant bloat

This review gives an overview of the current knowledge concerning the problem of foam formation in the process of anaerobic digestion in biogas plants that utilize renewable resources or biogenic waste material for biogas production. Process upsets in biogas production induced by foam formation can have a negative impact on the efficiency of biogas plants. The foam can block gas pipes and cause severe damage to the bioreactor equipment, ranging from a failure of the feeders to a damage of the roof of the biogas plant. The most common foam removal methods - stirring in the foam, adding anti-foaming agents, diminishing substrate feeding, and altering the biogas reactor management - are not always successful. However, the reasons for the excessive foam formation during the biogas production process have not yet been elucidated in detail. In contrast, foam building in the rumen of ruminants as a cause for bloat has been studied thoroughly. In general, the interaction between proteins, polysaccharides (mucilage), and small plant particles is assumed to be the crucial factor. As the fermentation process in the rumen has many similarities with the biogas production process, the current research results on bloat in ruminants are summarized and compared with the process of foaming in biogas plants.

Degradation processes of polydimethylsiloxane under thermal cracking conditions of hydrocarbons in an experimental pilot plant followed by size exclusion chromatography coupled to inductively coupled plasma high resolution mass spectrometry

In the oil and gas industry, silicon coming from antifoaming agents, is recognized to be an emergent contaminant for hydrotreatment catalyst due to its negative effect on their performance. Using a pilot plant, representative samples of the thermal degradation of antifoaming agent such as polydimethylsiloxanes (PDMS) were produced under evaluated thermal cracking of hydrocarbons with the presence or absence of steam. Micro size exclusion chromatography hyphenated to inductively coupled plasma high resolution mass spectrometry was used to characterize these samples. Under low temperature processing conditions at around 250°C, PDMS was not degraded in the presence of hydrocarbons. Under thermal cracking of hydrocarbons at 500°C, PDMS is degraded and formed intermediate polymers and low molecular weight compounds. A small amount of the initial PDMS can be present following the different operating conditions. The percentage of steam has a great influence on the degradation of intermediate polymers probably following a hydrolysis to produce low molecular weight species. The results presented bring preliminary results and a new insight on the degradation of PDMS under thermal cracking conditions. This work indicates that the different molecular weight silicon compounds can distillate in the various petroleum cuts and could be responsible for catalyst poisoning.

Preparation of Silicone-Modified Polyester Resin for Colored Steel Sheet

The coating resources for colored steel sheet using silicone-modified polyester resin were prepared and developed in order to fit rapid development of colored sheet industry in this paper. The dose of crosslink agent, pigment binder ratio, pigment, the dose of catalyst dispersant, antifoaming agent, surfactants were investigated by testing the performance of adhesion, rigidity (H) and MEK-resistance. Compared with commercially available resin SM3911, the flexibility of the coating has been gradually improved, T bends finally reached 0T, and can made colored steel sheet having an excellent processing performance. In addition, hardness also reached 4H, and wipe-resistant reached 105 per time.

A Study on Compatibility of an ASP Demulsifier with Defoaming Agent

During the Process of ASP Produced Fluid Treatment, a Considerable Amount of Chemical Agents Were Injected to the Production System due to Problems such as Heavy Emulsion, Scaling and Foaming, Etc. these Chemicals React on each other and Finally Coexist in the Produced Fluid. how about Compatibility between the Chemicals? Will they Strengthen or Weaken their Functions on each other? this Paper Has Confirmed the Effects and their Influences to the Produced Fluid through Lab Tests on Compatibility between Demulsifiers, Defoaming Agents and Proposed a Proper Concentration to Eliminate Influences Caused by the Uncompatibility. Therefore, it Reduces the Effect on the Water Quality.

Separation of Butanes and Butylenes by Extractive Distillation with MEK/NFM Mixed Solvent

The feasibility of methyl-ethyl-ketone (MEK) and N-formylmorpholine (NFM) as combination solvent for separation of butanes and butylenes by extractive distillation was investigated. Based on the thermodynamic studies and laboratory data, five butylenes-enriching plants of 30,000 t/a scale were established. The concentration of butylenes product were 97% (wt%), and the recovery of butylenes achieved was 90%. Antifoam agent was employed to prevent the solvent from foaming and worked effectively. As compared with NFM/MOR (morpholine) solvent system or DMF, MEK/NFM solvent system showed advantages such as low bottom temperature of strip column and low toxicity. Further comparison with ACN (acetonitrile) solvent system indicates that MEK/NFM system presented low residue in top production.

Effects of Inorganic Salts and Polymers on the Foam Performance of 1‐Tetradecyl‐3‐methylimidazolium Bromide Aqueous Solution

AbstractThe foaming performance of 1‐tetradecyl‐3‐methylimidazolium bromide (C14mimBr) aqueous solution, in the presence of polymers (PEG or PVA) or inorganic salts (NaBr, MgCl2, NaNO3, Na2SO4 or Na3PO4), was investigated at 25.0 °C by using the self‐made apparatus and the conductivity method. The experimental results show that the foaming ability and foam stability of the ternary aqueous systems of C14mimBr coexisting with PEG or PVA are stronger than those of the C14mimBr solutions in the absence of a polymer, and both the efficiency of foaming ability and foam stability of the surfactant solutions are evidently enhanced with an increase in polymer concentration. However, the addition of inorganic salts can decrease the foaming ability and foam stability of C14mimBr solution. Especially, the inorganic salts, with high valence state of the anion (SO42− and PO43−), are good antifoam agents which can remove and inhibit foam quickly. For the aqueous solution of the surfactant, the effect of temperature on foaming properties was also examined. The results show that both the foaming ability and stability of the foams of the surfactant solutions decrease with an increase in the temperature within the range from 25.0 to 45.0 °C.

S132014 電気防錆加工法の研究開発 : 水浄化性能について

In recent year, environmental degradation is concerned. The "sustainable development" has become important issue in Japan, because natural disaster triggered nuclear plant accident and environmental pollution is raised. Therefore, future petroleum crisis is feared. In manufacturing, machining fluid (metal working fluid: cutting oil, grinding fluid) is used for performance increasing. It contains oil, surface active agent, extreme pressure agent (CI, S, P etc.), anti foam agent, preservative agent, biocide etc.. It is concerned that several chemicals causes worker's health hazard while machining. Moreover, it is necessary that waste fluid treatment (incineration or coagulative precipitation etc.) is performed. Huge environmental load (CO_2 emission etc.) and disposal cost is necessary. Then, decreased or non-using of machining fluid is demanded in industry. Then, in this investigation, the electric rust preventive machining method system that uses only water as machining fluid, is proposed and developed. In part of this, water recycle system that enables to re-use water is developed. This water recycle system removes sludge, chip, fine particle, rust and ion, bacteria and pollutant (cesium etc.) etc. from used water. In addition, iodine (pollutant) reduction is evaluated. Contaminated water iodine (0.055mg/L) is decreased to less than O.OO1mg/L. Water purification performance is clarified. And, purified refined water quantity is achieved over 1OL/min. Furthermore, in order to more safety, water recycle system is installed ultraviolet radiation unit for sterilization of bacteria without biocide using.

The Product Carbon Footprint of EU beet sugar (Part II)

With regard to farming operations, all N-fertilizer was assumed to be in the form of mineral fertilizer, as there is no publicly available figure known for the average use of organic fertilizer (e.g. manure) in sugar beet cultivation in Europe. All the basic inputs to sugar beet cultivation were included, that is, seed, fertilisers, pesticides and diesel consumption for field work. Nitrous oxide, soil emissions (N2O, commonly known as laughing gas) from farming were included according to Biograce (i.e. 2.7% of applied N is emitted as N2O). Transport of sugar beet and adherent soil was also accounted for, and it was assumed that all transports are by 40-t truck. The emissions related to the return of empty trucks delivering beet to the factories were also accounted for in the Biograce data. GHG emissions linked to LUC (land use change, direct or indirect) were estimated to be negligible because all land used to grow beet, at least in the EU, is already arable land. With regard to factories, very small inputs were excluded. Specifically, most process chemicals used in sugar production such as NaOH or HCl for pH correction or antifoaming agents were assumed not to be significant for the overall result because they were used only in small quantities. However, as limestone is a processing aid used in larger amounts (approx. 2% per tonne of beet processed), it therefore was included.7 For surplus steam, which some factories co-produce, substitutes were difficult to establish, because they depend on the local situation. Since the resulting GHG credit for surplus steam was expected to be small as an EU average, no GHG credit for surplus steam was calculated. Potential emissions from water treatment systems were, on the other hand, not taken into account because there is insufficient data available about the different types of water treatment systems in operation in EU beet sugar factories. The emission factors of the process inputs used in the calculations are listed in Table 9.

Supercritical CO2 as an effective medium for a novel conversion of glycerol and alcohols in the heterogeneous telomerisation of butadiene

The selective telomerisation of 2,3-dimethylbuta-1,3-diene with several different mono- and polyalcohols proceeds in the presence of a heterogeneous palladium catalyst. By applying a green solvent (CO2), the selectivity of the reaction as well as the conversion of diene is easily moderated, imitating the results of reactions with organic solvents. In addition, the pressure tuning allows the driving of the reaction towards a highly selective synthesis of monotelomers, which could be valuable future intermediates in the production of surfactants or defoaming agents. Additionally, it was highlighted for the first time that the catalytic addition of glycerol and other polyalcohols to 2,3-dimethylbuta-1,3-diene is possible with complete avoidance of any volatile organic solvents.

Gastric Preparation for Upper Endoscopy

Gastric Preparation for Upper Endoscopy

Foam stability in microgravity

Within the context of the ESA FOAM project, we have studied the stability of aqueous and non-aqueous foams both on Earth and in microgravity. Foams are dispersions of gas into liquid or solid. On Earth, the lifetime of a foam is limited by the free drainage. By drainage, we are referring to the irreversible flow of liquid through the foam (leading to the accumulation of liquid at the foam bottom, and to a global liquid content decreases within the foam). When the liquid films become thinner, they eventually break, and the foam collapses. In microgravity, this process is no more present and foams containing large amounts of liquid can be studied for longer time. While the difference between foaming and not-foaming solutions is clear, the case of slightly-foaming solutions is more complicated. On Earth, such mixtures are observed to produce unstable froth for a couple of seconds. However, these latter solutions may produce foam in microgravity. We have studied both configurations for different solutions composed of common surfactant, proteins, anti-foaming agents or silicon oil. Surprising results have been obtained, emphasizing the role played by gravity on the foam stabilization process.

Evaluation of the efficiency of silicone polyether additives as antifoams in crude oil

AbstractIt is common for crude oil from wells to be accompanied by gas and water because of the presence of natural surfactants in the oil that stabilize the associated water. This causes foaming during processing in gas/oil separators because of the constant agitation and shear forces, which reduce the efficiency of the process and require chemical control by the addition of defoaming additives, or antifoams. In this work, we evaluated the chemical and physicochemical properties of commercial antifoam products based on silicone polyethers along with their efficiency in inhibiting foaming and water/oil (W/O) phase separation. The commercial surfactants were characterized by NMR spectroscopy, size exclusion chromatography, determination of solubility in different solvents, and measurement of the surface and interfacial tensions. A method to test the formation of foam in oil was used to mimic the operating conditions in gas/oil separators. Finally, tests were performed with the addition of aliquots of the additive solutions (30% p/v) in oil to evaluate their efficiency in breaking up the foam under different conditions. The results show that the most polar additive (SL2) was the most efficient in breaking up the foam. Additive SP1, which formed a heterogeneous phase in the oil, was also an efficient foam inhibitor and helped to separate these phases. The antifoam tests showed that these additives did not stabilize W/O emulsions, so they could be used in gravitational separation tanks in the field. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

High cell density growth of High Five suspension cells in DO-controlled wave-mixed bioreactors

Insect cells such as High Five cells used in the manufacture of biopharmaceuticals are best grown in wave-mixed bioreactors (1). This is due to the continual blending of foam with the culture medium which results from the wave-induced mixing and permanent renewal of the medium surface. Even the addition of an antifoam agent is not required. Process conditions which ensure maximum High Five cell densities and which have been reported to be about 8 x 106 cells x mL-1 (2) were determined in Biostat CultiBag RM50 optical experiments for batch mode and 1 L culture volume. Seed inoculum for these experiments was generated in single-use shake flasks (Corning) incubated in an Infors`Multitron shaker (27°C, 100 rpm, 25 mm shaking diameter). Biostat CultiBag RM50 optical was controlled in four different modes: non-pH- and non-DO-controlled, DO- controlled, pH-controlled, DO- as well as pH-controlled. The DO level was guaranteed by increasing the rocking rate up to 28 rpm and, if required by addition of pure oxygen. In process control was supplemented with off-line analyses of cell density, viability, metabolites (glucose, glutamine, glutamate, lactate, ammonium) and pH. While the influence of the type of bioreactor`s control on the maximum growth rate (0.041-0.044 h-1) and doubling time (15.6-17.7 h) was negligible, maximum cell densities were achieved with DO regulation (set point 50%). Maximum cell densities ranged between 8.2 and 9.4 x 106 cells x mL-1 and represent the highest values described for High Five cells so far in the literature. They are 35% higher compared to those seen in pH-controlled and non-controlled experiments. Controlling both DO and pH level did not lead to any further improvement of cell growth i.e. the range of growth parameter values was the same as that observed in the previous experiments. For High Five cell-based biopharmaceuticals this knowledge enables optimized seed inoculum/seed train production in wave-mixed bag bioreactors.

Fabrication and Characterization of Erbium-Doped Polymer Patterns by Lift-Off Process for Planar Optical Amplifiers

Erbium-doped aqueous polymer solutions were prepared using polyvinylpyrrolidone as a host polymer, potassium persulfate as a thermal cross-linking agent, erbium (III) trifluoromethane sulfonate as an erbium source, ethylene glycol as an antifoaming agent and DISPERBYK-180 as a dispersing agent with various weight ratios. The cross-linked, patterned and Er3+-doped polymer films were fabricated using the solutions by a lift-off process for application to planar optical amplifiers. The polymer films fabricated in this study showed excellent transmission of more than 90% over the visible and NIR regions, a high thermal decomposition temperature of about 380°C and high Er3+ concentration up to 20 wt.% based on a polymer matrix without aggregation, making this material sufficient for planar optical amplifiers.

Pesticide removal from waste spray-tank water by organoclay adsorption after field application to vineyards

The main objective of this work was to develop and test a pilot scheme for decontaminating pesticide-containing water derived from pesticide mixtures used to protect vineyards, in which the scheme comprises adsorption by an organoclay and includes a system where an enhanced or rapid microbial degradation of the adsorbed residues can occur. In laboratory experiments, the Freundlich adsorption coefficients of formulations of two fungicides, penconazole and cyazofamid, onto the organoclay Cloisite 20 A were measured in order to predict the efficiency of this organoclay in removing these fungicides from the waste spray-tank water. Subsequently, the adsorption tests were repeated in the pilot system in order to test the practical operation of the depuration scheme. The adsorption tests with the pilot system show 96% removal of both fungicides over a few hours, similar to the efficiency of removal predicted from the laboratory adsorption tests. The formulation type may influence the efficiency of clay recovered after adsorption. Regarding the waste disposal, for instance, the organoclay composted after the treatment, cyazofamid showed significant dissipation after 90 days, whereas the dissipation of penconazole was negligible. The depuration scheme developed showed to be efficient for decontaminating pesticide-containing water derived from vineyards, but additional treatments for the adsorbed residues still appear to be necessary for persistent pesticides. However, future decontamination research should be attempted for water contaminated with pesticides containing antifoaming agents in their formulations, in which case the present pilot system could not be applied.

Mechanical Inhibition of Foam Formation via a Rotating Nozzle

We recently discovered that bubble formation can be substantially prevented when an aqueous solution is sprayed into a bath of the same solution provided that any two consecutive drops impacting the same surface location do so with a time interval greater than the capillary relaxation time. Building on this observation, here we report a mechanical means of preventing foam formation during liquid addition: the nozzle delivering the liquid is rotated sufficiently rapidly so that no two successive drops impact the interface at the same location. Foam formation is reduced by as much as 95% without any chemical anti-foaming agents.

Antifoam addition to shake flask cultures of recombinant Pichia pastoris increases yield.

BackgroundPichia pastoris is a widely-used host for recombinant protein production. Initial screening for both suitable clones and optimum culture conditions is typically carried out in multi-well plates. This is followed by up-scaling either to shake-flasks or continuously stirred tank bioreactors. A particular problem in these formats is foaming, which is commonly prevented by the addition of chemical antifoaming agents. Intriguingly, antifoams are often added without prior consideration of their effect on the yeast cells, the protein product or the influence on downstream processes such as protein purification. In this study we characterised, for the first time, the effects of five commonly-used antifoaming agents on the total amount of recombinant green fluorescent protein (GFP) secreted from shake-flask cultures of this industrially-relevant yeast.ResultsAddition of defined concentrations of Antifoam A (Sigma), Antifoam C (Sigma), J673A (Struktol), P2000 (Fluka) or SB2121 (Struktol) to shake-flask cultures of P. pastoris increased the total amount of recombinant GFP in the culture medium (the total yield) and in the case of P2000, SB2121 and J673A almost doubled it. When normalized to the culture density, the GFP specific yield (μg OD595-1) was only increased for Antifoam A, Antifoam C and J673A. Whilst none of the antifoams affected the growth rate of the cells, addition of P2000 or SB2121 was found to increase culture density. There was no correlation between total yield, specific yield or specific growth rate and the volumetric oxygen mass transfer coefficient (kLa) in the presence of antifoam. Moreover, the antifoams did not affect the dissolved oxygen concentration of the cultures. A comparison of the amount of GFP retained in the cell by flow cytometry with that in the culture medium by fluorimetry suggested that addition of Antifoam A, Antifoam C or J673A increased the specific yield of GFP by increasing the proportion secreted into the medium.ConclusionsWe show that addition of a range of antifoaming agents to shake flask cultures of P. pastoris increases the total yield of the recombinant protein being produced. This is not only a simple method to increase the amount of protein in the culture, but our study also provides insight into how antifoams interact with microbial cell factories. Two mechanisms are apparent: one group of antifoams (Antifoam A, Antifoam C and J673A) increases the specific yield of GFP by increasing the total amount of protein produced and secreted per cell, whilst the second (P2000 or SB2121) increases the total yield by increasing the density of the culture.

Characterisation of HFBII biosurfactant production and foam fractionation with and without antifoaming agents

The effects of foaming on the production of the hydrophobin protein HFBII by fermentation have been investigated at two different scales. The foaming behaviour was characterised in standard terms of the product enrichment and recovery achieved. Additional specific attention was given to the rate at which foam, product and biomass overflowed from the fermentation system in order to assess the utility of foam fractionation for HFBII recovery. HFBII was expressed as an extracellular product during fed-batch fermentations with a genetically modified strain of Saccharomyces cerevisiae, which were carried out with and without the antifoam Struktol J647. In the presence of antifoam, HFBII production is shown to be largely unaffected by process scale, with similar yields of HFBII on dry matter obtained. More variation in HFBII yield was observed between fermentations without antifoam. In fermentations without antifoam, a maximum HFBII enrichment in the foam phase of 94.7 was measured with an overall enrichment, averaged over all overflowed material throughout the whole fermentation, of 54.6 at a recovery of 98.1%, leaving a residual HFBII concentration of 5.3 mg L(-1) in the fermenter. It is also shown that uncontrolled foaming resulted in reduced concentration of biomass in the fermenter vessel, affecting total production. This study illustrates the potential of foam fractionation for efficient recovery of HFBII through simultaneous high enrichment and recovery which are greater than those reported for similar systems.