Foam arises in many industrial processes. It can be produced biologically—due to anaerobic digestion or brewing—during wastewater cleanup, or while cleaning and preparing starchy vegetables.
Antifoam additives are often used to prevent foam buildup in industrial processes, but the amount used can be difficult to control, and overdosing can be costly. Failing to use sufficient additives can result in foam-over events which require extensive cleanup, while excessive use is expensive and creates the potential for contamination.
We have helped many clients address the specific needs of their manufacturing and treatment plants, significantly improving their cost and time savings, and ultimately, their profitability.
Below are some of our clients’ common concerns:
“We need to reduce our use of antifoam additives in order to control costs.”
In processes where foam must be kept at bay, processing and manufacturing plants often rely on continuous dosing of antifoaming agents. This method assumes that the process will always produce foam, even when it doesn’t.
In instances where there is a limited budget for remedying the issue, the typical short-term solution is to install a manual foam control solution, which allows operators to press a button to dispense antifoam agents when needed.
However, this relies heavily on someone noticing the problem and keeping tabs on it until it is resolved. This results in a tendency to “overdose,” because pumps are left running too long due to operators being called away to attend to other matters. Thus, whether this reactive strategy is automated or manually implemented, it is clear that the high cost of de-foaming additives makes this method an expensive foam control solution.
The ideal approach is to Install an automated foam detection and control system that adds antifoam chemical only when sensors measure foam activity, which eliminates reliance on continuous human intervention, and significantly reduces the amount of chemical used.
“We keep having issues with unexpected foam overflows, which result in downtime and require extensive cleanup.”
In plants where foam is a common occurrence, antifoam chemicals are often continuously added to counteract foam generation. However this does not prevent “foam-outs” or “foam-overs” caused by unexpected changes in conditions, necessitating the manual or boosted use of antifoam chemical after the event.
This is not an efficient or effective approach to controlling foam, and often leads to overdosing due to the urgency of resolving the situation quickly. In these situations conditions often seesaw between excessive and insufficient use of antifoam additives, and operators find themselves frustrated with continued frequent foam-outs despite increasing usage of antifoam.
Where budgets don’t allow for a technology-based solution, the best stopgap is to lower process medium levels, as this will reduce foam height and reduce or eliminate foam overs. The down side of this is that lower medium levels unfortunately mean lower yields as well.
The best possible solution is to implement a foam detection system that uses a shot and delay method or—for continuously foaming conditions—a PI control regime to only add antifoam chemicals when needed will ensure that the potential for foam-outs is mitigated before problems arise.
Even if you choose not to automate foam control, a lower cost solution is to implement foam detection instrumentation that immediately raises awareness of a foaming event occurring. Immediate warning will allow more time to deal with the problem before it gets out of hand.
“Production numbers have been down due to antifoam chemicals contaminating the end product.”
Switching to an automated foam control method which dispenses only as much antifoam as is measured by foam detection systems significantly reduces the total amount of antifoam agent used, mitigating the potential for product contamination.
Traditional semi-autonomous foam-control systems rely on the use of a continuous feed of antifoam chemical. But the resulting high levels of antifoam often find their way into the end product, requiring the contaminated product to be dumped.
“We have to dedicate employees to monitoring foam levels. We would like to be able to devote them to more critical and profitable tasks, and potentially reduce our overhead.”
Fully automated foam detection and control systems can manage foam without the need for human intervention, freeing up staff to attend to other necessities. Systems with automated antifoam control systems can even be left unattended during night shifts and weekends, potentially allowing for either reduced staffing during these periods, or re-dedication of employees to other, more critical needs.
“Our final product requires multiple washing stations to remove antifoaming agent residue.”
The stopgap solution for reducing reliance on the use of antifoamer chemicals and washing stations is to reduce the process flow and agitation that creates foam. However, a lower flow inevitably means lower yields.
In the long term, the best results are produced by implementing an automated foam control solution which utilizes three probes to detect foam at various process states and can dispense antifoam chemicals as needed, early in the foam formation process.
“The probes we currently use to monitor foam levels become fouled on a regular basis, requiring frequent manual cleaning. Is there a better measurement solution?”
A lower cost solution to this issue is to install a capacitance level measuring instrument. One of reasonable quality and price will have an accuracy rate of about 60%.
Obviously, this isn’t an ideal solution. There are now probes on the market which incorporate technology which control for the effect of accumulated material on the probe. This allows the monitoring technology to effectively ignore the product buildup, and continue to deliver accurate readings.
“We need to show the EPA and other regulatory agencies that we are reducing the levels of chemicals and other contaminants in the effluent we discharge into the environment.”
Systematic reduction of the use of antifoam chemicals throughout the process will reduce final discharge levels. Adopting an automatic “dose as required” system, rather than a “dose continuously” or “manual dose on upset” can help reduce the amount of antifoam chemical used, leading to an overall reduction of antifoam chemical in final effluent discharge.
This has been an effective approach for a variety of industries and applications, from vegetable processing to oil and gas production.
We have found that in wastewater treatment, foam can sometimes be controlled with water sprays which disrupt bubbles in foam, keeping them at bay. This approach does not, however, change any foaming tendency in the flowing stream as it still contains surfactants (the substances which cause foam). Monitoring the stream after or above the water spray nozzles can help determine whether antifoam chemical is also necessary. Foam control systems which feature multiple inputs allow for multistage process monitoring, and can dispense antifoam chemicals as needed. While the need for antifoam chemicals is not eliminated, water sprays can reduce the amount of antifoam chemicals needed.
Are you dealing with unwanted side-effects of industrial foam? Our foam control solution was implemented at one of Europe’s largest cereal manufacturing sites, which produces thousands of tons of breakfast cereal every year for distribution.
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Frequently Asked Questions
How can bioreactor processing yields be increased?
By implementing foam detection probes which dispense antifoam chemical only when needed, avoiding excessive levels of antifoam which can reduce cell interaction, while preventing foam formation that interferes with cell growth.
The bioreactor filter becomes clogged with foam, causing the pressure relief valve (PRV) to vent. How can this be prevented?
Install a foam control system which allows for real-time monitoring and prevention of foam buildup, which will prevent filter clogging and ensure that the PRV does not vent and create a mess.
Are there bioreactor probes that don’t give false positive readings when they are coated or fouled?
New probes have come onto the market which utilize a sensing method that allows them to control for coating and fouling and continue to deliver accurate foam measurements.
What is the best way to control foam-over events?
Implement foam detection instrumentation that will immediately raise awareness of a foaming event occurring and allow for a rapid response. This saves labor associated with cleanup, and also prevents the creation of slipping hazards.
How can I reduce chemical agents in my final effluent?
Systematic reduction of the use of antifoam agents throughout the wastewater treatment process will reduce final discharge levels. The best means for doing so is the adoption of an automated control system that only doses as required.
paper & pulp manufacturing
How can I reduce the number of holes and spots in my final paper product?
These defects are often due to entrained air/foam in the pulp feed. Installing a foam detection probe in the head box allows for the measurement of foam, and the dispensation of the appropriate amount of defoamer chemical.
How can I reduce foam buildup in our settling tanks?
Strategically placing foam detection probes and control systems will reduce the incidence of foam buildup in open tanks, vessels and pits throughout the pulp mill.
How can I fix slow and inconsistent drainage rates on our forming tables?
Defoamers can often remedy this issue, but they should be introduced to the feed before equipment that can entrain air, such as hydrocyclones. Monitoring for surface foam can provide a trend that will allow the chemical feed to be increased or decreased accordingly and keep the air content within the pulp more consistent.
How best can we reduce the amount of antifoam residue on our end product?
When antifoam chemicals are present in such high quantities that they contaminate food products, manual management of foam is usually to blame. Installing an automated foam detection and control system will significantly reduce the amount of antifoam used, as it is only dispensed when needed, in smaller quantities than are necessary when foam formation is visibly noticeable.
How can we keep foam from entering and potentially damaging process equipment?
Foam generally only presents a threat to process equipment when it forms in such large quantities that foam-over events occur. A foam detection system that can automatically inject antifoam chemicals when foam is present will prevent such events from happening.
Can we automate how we control foam in the food manufacturing process to reduce our housekeeping costs?
As with damage to equipment, foam-overs are the products of inadequate foam management, usually in the form of visual inspection and manual adding of antifoam additives. Transitioning to an automatic detection and control system can quickly resolve issues with rising foam.
Oil & Gas
How can we stop liquid—in the form of foam—from being carried through the amine scrubber and associated knock-out vessels downstream, and getting into the fuel gas compressors?
The installation of foam detection systems in both the scrubber and subsequent knock-out pot will alert operations to the presence of foam in the system and allow for its remediation before it can be carried into the compressors.
We use a continuous dosing method to control foam formation and protect our compression set. How can we reduce chemical usage and associated costs?
Controlling foam can be a fully automated process, and eliminate extraneous dosing being performed when no foam is present. This can translate to significant cost savings against a relatively low investment in operating infrastructure.
How do we show the EPA that we are reducing chemicals and contaminants in effluent we’re discharging into the environment?
Many chemicals are used to convert crude oil into refined products, including antifoam additives, which are injected into the process and waste streams to aid in foam reduction and elimination. Monitoring for foam generation in waste streams, pits, and channels can reduce antifoam chemical consumption, and consequently reduce total chemical discharge.
We are losing ore in foam-over situations. How can we better control foam levels?
Installing probes at strategic points along the process system will give early warning of foaming issues. Furthermore, automating the dosing of antifoamers at those points will prevent product loss due to overflows.
We are constantly under scrutiny from regulators regarding plant discharge into local water systems—how can we reduce chemical discharge?
Oftentimes mineral processors consistently dose water in effluent plants for foam. Effluent does not always have a tendency to foam—a very visible form of pollution—so there is no need to constantly dose it with antifoam. Fitting a detection system that will add defoamer chemical only when needed will reduce the amount of those chemicals in the stream.