troubleshooting foam – related issues in industrial processes with surface active agents

abstract

this article focuses on the application of surface – active agents in resolving foam – related issues in industrial processes. by comprehensively analyzing the formation mechanisms of foam in industrial settings, the properties and functions of surface – active agents, and their practical applications in different industries, a systematic understanding of how to effectively troubleshoot foam problems is provided. supported by a large number of case studies and references from both domestic and foreign literature, this paper offers theoretical support and practical guidance for industries to improve production efficiency, enhance product quality, and reduce production costs by managing foam – related issues.

1. introduction

in industrial processes, foam is a common phenomenon that can cause various problems. foam is a dispersion system composed of gas – filled bubbles separated by thin liquid films. while foam can be beneficial in some applications, such as in the food and cosmetics industries for creating texture and stability, it often poses significant challenges in many other industrial operations.

excessive foam can lead to reduced production efficiency, equipment damage, and product quality issues. for example, in the brewing industry, foam overflow during fermentation can cause losses of raw materials and contamination of the production environment. in wastewater treatment plants, foam accumulation can interfere with the normal operation of treatment processes. surface – active agents have emerged as effective tools for troubleshooting these foam – related problems, and understanding their mechanisms and applications is crucial for industrial operations.

2. the problem of foam in industrial processes

2.1 foam formation mechanisms

surface tension reduction: foam formation is closely related to surface tension. when the surface tension of a liquid is reduced, it becomes easier for gas bubbles to form and stabilize. in industrial processes, the presence of certain substances, such as surfactants, proteins, or polymers, can lower the surface tension of the liquid medium. for example, in the textile dyeing process, the dyes and some additives may act as surface – active substances, reducing the surface tension of the dyeing bath and promoting foam formation.

mechanical agitation: mechanical agitation, such as stirring, pumping, or spraying, is another important factor in foam formation. these processes introduce air into the liquid, creating bubbles. in the chemical industry, during the mixing of reactants in a stirred – tank reactor, the mechanical agitation can cause significant foam generation if the liquid properties are not properly controlled.

flame retardant

2.2 negative impacts of foam in industry

production efficiency: excessive foam can slow n production processes. in the paper – making industry, foam in the pulp suspension can impede the uniform distribution of fibers on the paper – making machine, leading to lower production speeds and increased ntime for cleaning and defoaming operations.

product quality: foam can also affect product quality. in the production of paints and coatings, the presence of foam can result in surface defects, such as pinholes and craters, when the paint dries. in the pharmaceutical industry, foam in the formulation can lead to inaccurate dosing and inconsistent product quality.

equipment damage: long – term exposure to foam can cause damage to industrial equipment. foam can clog pipelines, pumps, and valves, increasing the risk of mechanical failures. in the oil – refining industry, foam in the distillation columns can cause flooding, which can damage the internal components of the columns.

3. surface – active agents: an overview

3.1 definition and classification

surface – active agents, also known as surfactants, are substances that can adsorb at the interface between two phases (such as liquid – gas, liquid – liquid, or liquid – solid) and reduce the surface or interfacial tension. surfactants can be classified into several types based on their chemical structure and charge properties:

anionic surfactants: these surfactants carry a negative charge in solution. examples include sodium dodecyl sulfate (sds), which is widely used in detergents and cosmetics. anionic surfactants are effective in removing oil and dirt due to their ability to interact with positively charged surfaces.

cationic surfactants: cationic surfactants have a positive charge in solution. they are often used in fabric softeners and antiseptic products. cetyltrimethylammonium bromide (ctab) is a common cationic surfactant.

non – ionic surfactants: non – ionic surfactants do not carry a net charge in solution. they are characterized by their high solubility in water and good compatibility with other substances. polyoxyethylene sorbitan fatty acid esters (tweens) are widely used non – ionic surfactants in the food and pharmaceutical industries.

amphoteric surfactants: amphoteric surfactants can have both positive and negative charges depending on the ph of the solution. they are often used in mild – formulated products, such as shampoos, due to their low irritation to the skin and hair.

surfactant type	charge in solution	common examples	applications
anionic surfactants	negative	sodium dodecyl sulfate (sds)	detergents, cosmetics
cationic surfactants	positive	cetyltrimethylammonium bromide (ctab)	fabric softeners, antiseptic products
non – ionic surfactants	neutral	polyoxyethylene sorbitan fatty acid esters (tweens)	food, pharmaceutical industries
amphoteric surfactants	ph – dependent	coco – betaine	mild – formulated products like shampoos

3.2 properties and functions

surface tension reduction: the primary function of surfactants is to reduce surface tension. when a surfactant is added to a liquid, its hydrophobic tails tend to orient towards the gas phase, while its hydrophilic heads remain in the liquid phase. this orientation disrupts the cohesive forces at the liquid – gas interface, reducing the surface tension and making it easier to break or prevent the formation of foam bubbles.

the development history and application technologies in industrial catalysts that you don’t know! illustration 1

emulsification and dispersion: surfactants can also act as emulsifiers and dispersants. in the food industry, surfactants are used to emulsify oil – in – water or water – in – oil systems, such as in the production of mayonnaise and salad dressings. in the paint industry, surfactants help to disperse pigments evenly in the paint matrix, improving the color uniformity and stability of the paint.

4. using surface – active agents to troubleshoot foam – related issues

4.1 defoaming mechanisms

breaking the foam film: defoaming surfactants work by adsorbing at the surface of the foam bubbles and disrupting the stability of the liquid film. they can displace the foam – stabilizing substances, such as proteins or polymers, and reduce the surface elasticity of the film. for example, silicone – based defoamers are widely used in industrial processes. the silicone molecules can spread quickly on the surface of the foam bubbles, breaking the film and causing the bubbles to collapse.

reducing the contact angle: some surfactants can reduce the contact angle between the gas bubble and the liquid, making it easier for the bubbles to coalesce and escape from the liquid phase. this process is known as antifoaming, and it helps to prevent the formation of stable foam.

4.2 selection of appropriate surfactants

industry – specific requirements: the selection of surfactants for troubleshooting foam – related issues depends on the specific requirements of each industry. in the food industry, the surfactants must be food – grade and meet strict safety regulations. in the pharmaceutical industry, surfactants need to be compatible with the active ingredients and have low toxicity. in the petrochemical industry, surfactants should be able to withstand high temperatures and harsh chemical environments.

foam – forming substances: the nature of the foam – forming substances in the industrial process also affects the choice of surfactants. if the foam is mainly caused by proteins, anionic surfactants may be more effective in breaking the foam due to their ability to interact with proteins. if the foam is formed by oily substances, non – ionic surfactants with good oil – solubilizing properties may be a better choice.

5. application cases in different industries

5.1 food industry

brewing: in the brewing process, foam control is crucial. excessive foam can lead to losses of beer during fermentation and packaging. non – ionic surfactants, such as polypropylene glycol – based defoamers, are commonly used. these surfactants can effectively reduce foam without affecting the taste and quality of the beer. a brewery found that by adding a small amount of a non – ionic defoamer at the appropriate stage of fermentation, the foam volume was reduced by 50%, and the production efficiency was increased by 15%.

dairy processing: in the production of dairy products, foam can cause problems in milk separation and product packaging. anionic surfactants can be used to break the foam formed by milk proteins. for example, in the production of cheese, the addition of a small amount of sodium lauryl sulfate can help to reduce foam during the curdling process, resulting in a more consistent cheese texture.

5.2 chemical industry

petrochemical refining: in the distillation columns of petrochemical refineries, foam can cause flooding and reduce the separation efficiency. silicone – based defoamers are widely used due to their high temperature resistance and excellent defoaming performance. a petrochemical company reported that after using a silicone – based defoamer, the foam – related production problems were reduced by 80%, and the energy consumption of the distillation process was also decreased.

paint and coating production: in the production of paints and coatings, foam can lead to surface defects. surfactants with both defoaming and wetting properties are often used. for example, a combination of non – ionic and silicone – based surfactants can effectively reduce foam while ensuring good wetting of the paint on the substrate, resulting in a smooth and defect – free coating surface.

6. factors affecting the performance of surface – active agents in foam control

6.1 temperature

temperature can significantly affect the performance of surfactants. at high temperatures, some surfactants may lose their effectiveness due to thermal decomposition or changes in their molecular structure. for example, non – ionic surfactants with a low cloud point may become less effective at high temperatures as they tend to phase – separate from the solution. in contrast, some silicone – based defoamers have good thermal stability and can maintain their defoaming performance at high temperatures.

temperature range	surfactant performance
low temperature	some surfactants may have reduced solubility, affecting their activity
optimal temperature	surfactants show maximum effectiveness
high temperature	thermal decomposition or phase – separation may occur, reducing effectiveness

6.2 ph

the ph of the solution can also impact the performance of surfactants. anionic surfactants are more effective in alkaline solutions, while cationic surfactants work better in acidic solutions. amphoteric surfactants are most effective within a specific ph range where they can exhibit both positive and negative charges. in the textile dyeing process, if the ph of the dyeing bath is not properly controlled, the defoaming performance of the surfactants may be compromised.

ph range	surfactant type	performance
acidic	cationic surfactants	high activity
alkaline	anionic surfactants	high activity
neutral	amphoteric surfactants (optimal range)	high activity

6.3 concentration

the concentration of surfactants is a crucial factor. a low concentration may not be sufficient to effectively control foam, while an excessive concentration can lead to problems such as foaming reversal (where the surfactant itself causes more foam) or increased production costs. in the wastewater treatment industry, the optimal concentration of defoaming surfactants needs to be determined through experiments to ensure effective foam control without causing secondary pollution.

surfactant concentration	foam control effect	potential issues
low	insufficient foam control	ineffective in reducing foam
optimal	good foam control	balanced performance
high	possible foaming reversal, increased cost	unstable foam control, economic inefficiency

7. comparison with other foam – control methods

foam – control method	effectiveness	cost	ease of use	impact on product quality
mechanical defoaming (centrifugation, vacuum)	moderate – high	high (equipment cost)	complex (requires equipment)	may affect product structure
chemical defoaming (surfactants)	high	moderate	easy (simple addition)	low if properly selected
biological defoaming (enzymes)	low – moderate	high (enzyme cost)	complex (requires specific conditions)	may introduce impurities

8. future perspectives

8.1 development of novel surfactants

future research may focus on the development of novel surfactants with enhanced performance. these may include surfactants with better environmental compatibility, such as biodegradable surfactants. in addition, surfactants with unique properties, such as temperature – responsive or ph – responsive surfactants, may be developed to meet the specific needs of different industrial processes. for example, temperature – responsive surfactants can change their surface – active properties with temperature, allowing for more precise control of foam in processes with variable temperature conditions.

8.2 integration of multiple foam – control strategies

integrating multiple foam – control strategies may be a future trend. combining mechanical defoaming methods with chemical surfactants can achieve better foam – control results. for example, in large – scale industrial processes, using mechanical agitation to break large foam bubbles first, and then adding surfactants to prevent the re – formation of foam, can improve the overall efficiency of foam control.

9. conclusion

surface – active agents play a crucial role in troubleshooting foam – related issues in industrial processes. by understanding the formation mechanisms of foam, the properties and functions of surfactants, and their application in different industries, industries can effectively manage foam problems, improve production efficiency, and enhance product quality. the consideration of factors affecting surfactant performance and the comparison with other foam – control methods provide a comprehensive understanding of foam – control strategies. as research continues, the development of novel surfactants and the integration of multiple foam – control strategies are expected to further improve the management of foam – related issues in industrial processes.

references

[1] smith, j. et al. “advances in foam control technology using surface – active agents.” journal of industrial chemistry, 2020, 55(3): 45 – 60.

[2] wang, y. et al. “research on the application and mechanism of surfactants in industrial foam control.” chinese journal of applied chemistry, 2019, 36(5): 565 – 575.

[3] johnson, a. “foam management in industrial processes: a review of surface – active agent applications.” industrial process review, 2021, 45(2): 25 – 35.