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Posted by Compressed Air & Gas Treatment Team on 26 Apr 2018
In an industrial manufacturing plant, coalescing filters are probably the most important piece of purification equipment found in a compressed air system. They treat six of the ten main contaminants found in compressed air (atmospheric particulate, rust, pipe scale, micro-organisms and aerosols of oil and water). But more importantly, they are also used to protect refrigeration and adsorption (desiccant) air dryers from contamination.
This blog compares the benefits of installing a pair of coalescing filters in series versus a 2 in 1 filter in terms of differential pressure, dirt holding capacity, and total cost of ownership.
Typically, coalescing compressed air filters are installed close to where the compressor is located (either in the compressor room on larger installation or on the compressor itself for smaller fixed or portable compressors).
In order to effectively reduce the aerosols of oil and water, micro-organisms and particles to a level that will protect the compressed air dryer requires the use of a fine filter (treating contaminants down to 0.01 micron).
The particulate found in a compressed air system is of varying sizes and as this filter is very fine, it will block rapidly with large particles (especially rust and pipe scale).
As the filter blocks, the differential pressure across the filter increases. This not only reduces the available pressure downstream, it also requires the compressor to generate the compressed air at a higher pressure, resulting in higher operating costs.
On average, it is found that for every 1 bar additional generation pressure there is a loss of 7% in specific energy, therefore keeping pressure losses low helps reduce operating costs.
Running a compressed air filter with high differential pressure is therefore very costly and keeping pressure losses as low as possible is imperative. One way to keep the pressure losses low is to change the filter element on a frequent basis (every 3-6 months). Another way is to oversize the filter; however, making a filter too large has its own issues in terms of filtration performance, purchase cost and installation. Neither way is a cost-effective compressed air treatment solution.
If the fine filter could be protected, the pressure losses could be reduced, therefore the most cost-effective solution is to install a pair of coalescing filters in series.
Each filter will reduce the same 6 contaminants but to differing levels of purity. The first filter, a general purpose filter protects the second, a high-efficiency filter from bulk contamination. This not only improves filtration performance but more importantly, reduces pressure losses and operational costs. Additionally, it also extends the service life of the element from 3-6 months to 12 months.
Yes, there are single filter alternatives, but care has to be taken with this type of filter as they do not always provide the perceived benefits.
In an attempt to reduce the pressure losses associated with compressed air filters, a number of manufacturers are now offering 2 in 1 filters. These are claimed to reduce the pressure losses associated with having two filter housings (and therefore energy consumption) whilst providing the same level of purification (i.e. particulate retention & oil carryover down to 0.01 micron / 0.01 mg/m3 or lower). In theory, the thought process is a sound one, however, these types of filter do not always deliver in practice.
In a compressed air filter, pressure losses are a combination of fixed pressure loss and incremental pressure loss. Fixed pressure losses are designed into the filter from the beginning and come from the filter housing and element endcap designs whereas incremental pressure losses come from the filter element as it starts operating. Pressure losses for compressed air purification equipment are stated as dP or differential Pressure.
Literature dP is often used to select one filter brand over another, however many users are unaware that this data is only indicative of a filter in a clean, “as new” condition and does not indicate how a filter blocks as it operates.
When selecting a filter, its blockage characteristics must also be considered as this is an indication as to the filters dirt holding capacity (and true operational cost).
Therefore, to show the real performance of the 2 in 1 type of filter and the true benefits of their new OIL-X filter range, a comparative test between a pair of Parker domnick hunter OIL-X coalescing filters (Grades AO + AA) and a single 2 in 1 filter was undertaken.
As the filters on test are coalescing filters, they were wetted out with oil aerosol (in accordance with ISO12500-1, the international standard for coalescing filter testing) to give an initial saturated dP representative of a new filter as it enters the first days of service. Oil carryover performance was also recorded.
Results of the initial ISO12500-1 testing showed that whilst the OIL-X AO + AA combination achieved the claimed literature performance for oil carryover and initial wet dP, the 2 in 1 filter oil carryover performance was 87% higher than literature claims and initial saturated dP 5% higher.
The second test determines the dirt loading characteristics of the two offerings by injecting and diffusing equal amounts of test particulate into the air stream and measuring the dP (this is done 12 times to simulate monthly particulate loading).
So whilst the initial performance of the two filters may look similar in literature, actual dirt load testing indicates otherwise as can be seen in the graph. Testing confirms that a pair of Parker domnick hunter OIL-X filters have a much higher dirt holding capacity than the 2 in 1 filter and will, therefore, have significantly lower operational costs.
From the test data, true operational costs can now be calculated and the table below shows the financial savings available by installing a pair of Parker OIL-X filters over a 2 in 1 filter.
Based upon 37kW compressor / Cost of electricity £0.10. Parker OIL-X savings will be greater with larger filter/compressor combinations.
The table highlights operational costs, however, when selecting compressed air purification equipment, the total cost of ownership (TCO) should always be considered (purchase price / operational costs/maintenance costs). The initial purchase price for the two Parker OIL-X filters is only 26% higher than the 2 in 1 filter whilst a pair of Parker OIL-X filter elements is 42% lower than a single element for the 2 in 1. As the 2 in 1 filter has a lower operating lifetime than OIL-X, it may require 2 element changes per year in which case the pair of OIL-X elements is 183% lower cost than a pair of 2 in 1 elements. What seems like a low-cost alternative may turn out to be a costly investment.
The new OIL-X filter range is the latest addition to Parker's comprehensive line of compressed air and gas treatment product solutions. The new OIL-X technology has been designed to carefully balance the need for precise compressed air quality with the need for low dP, low energy consumption and low lifetime cost.
Parker domnick hunter OIL-X filters incorporate unique flow management devices to significantly reduce the pressure losses associated with poor housing designs whilst their filter elements use airflow management technology, specially selected filtration media, energy efficient coatings and unique deep pleated element construction. This not only ensures air quality, it also provides a high dirt holding capacity, culminating in a filter element dP that starts low and remains low for the 12-month lifetime of the filter element.
All Parker domnick hunter OIL-X filtration grades have performance 3rd party validated by Lloyds register in accordance with international standards and are backed up by an air quality guarantee.
For more information on Parker's compressed air treatment solutions, download the brochure.
This blog was contributed by Mark White, compressed air treatment applications manager, Parker Gas Separation and Filtration Division, EMEA.
10 Contaminants Affecting Your Compressed Air System - Part One
10 Contaminants Affecting Your Compressed Air System – Part Two
Compressed Air Treatment Solutions for Today's Manufacturing Plants
Seven Myths About Oil-Free Compressors
The consequences of failure during downstream processing are severe. Following the Affinity Chromotography stage, the value of the product increases significantly at every step. A failure at the final bulk filling stage, therefore, could lead to the waste of millions of dollars’ worth of drug product.
It’s vital, therefore, to safeguard the bulk filling process. But traditional methods of conducting bulk fill operations have several disadvantages including:
This introduces the possibility of human error to the bulk filling process. It is also labour intensive, meaning that process operators need to divert their resources into this task.
When bulk filling is carried out manually, investment must be made in operator training. This can be costly, both financially and in terms of the time dedicated to it by personnel.
By using a range of components from several different suppliers in the bulk filling process, there is more potential for variation – and more time must be spent on sourcing and ordering suitable components.
In traditional bulk fill operations, laminar air flow must be maintained and validated to protect the products from contamination. This requires time and resources.
At the shipping stage, poor handling of bottles – and the use of unsuitable containers – can lead to damage to products before they even arrive at their destination.
Traditional methods of bulk filling introduce variability into the process. If bulk filling operations aren’t standardized, they can be subject to a number of factors which can impact the final product. Factors such as different flow rates applied by different operators come into play.
Automating and enclosing bulk fill operations can address the challenges detailed above and increase safety for operators. Parker Bioscience Filtration has developed the SciLog® SciPure FD system as an automated and integrated single-use system for final bulk filtration, filter integrity testing and dispensing into final bulk product containers.
Here are some of the benefits:
This reduces the risk of human error from manual handling and allows operators’ resources to be spent on other tasks.
Standardizing operations means that training can be simplified and variations in the process can be eliminated.
Enclosing the process allows operators to process highly potent molecules and protects both the operators and the process. And, as the flow path is completely enclosed, both filtration and dispensing can be performed in areas of lower classification, eliminating the requirement for vertical laminar flow cabinets.
The SciLog® SciPure FD system benefits from innovative component selection based around material science studies, improved filling accuracy (+/-1%), and greater flexibility in the scale of filling (from 50ml samples to 20L).
The system features include a barcode reader for manifold tracking, reverse flow and purge options to maximize product recovery and fully programmable alarms and interlocks to product and process.
To reduce the risk of damage to the product when shipping, Parker Bioscience Filtration has designed a fully validated shipping solution to complement and extend the capabilities of the SciLog® SciPure FD System. Parker Bioscience Filtration has created a unique bottle design that offers manufacturers the confidence that bulk drug products will arrive at their final destinations without contamination.
Parker Bioscience Filtration drew on its extensive material science knowledge during the development of the bottle and material selection was based on an FMEA study. The bottle integrity has been validated down to -89˚C.
Parker Bioscience has also developed an anti-foaming device that eliminates foam and enables a higher filling speed.
The development of the SciLog® SciPure FD System is an example of the change in the vendor/end user relationship: by using a vendor such as Parker Bioscience Filtration, which can provide a complete solution, end users can increase their productivity and gain greater control and protection over their processes.
This post was contributed by Graeme Proctor, product manager (single-use technologies), Parker Bioscience Filtration, United Kingdom
Parker Bioscience Filtration specializes in automating and controlling single-use bioprocesses. By integrating sensory and automation technology into a process, a manufacturer can control the fluid more effectively, ensuring the quality of the final product. Visit www.parker.com/bioscience to find out more.
Automated Single-Use Technology and Its Impact on Quality
Engineering Managers: Streamline Your Bioprocess With Automation
What's Stopping You From Automating Your Single-Use Process?
Four Sources of Process Variation in Biopharmaceutical Manufacturing
Protecting Your Bioprocess From the Risk of Human Error
Mycoplasma contamination events, although rare, can have an enormous and immediate negative impact on biomanufacturers leading to reduced productivity and delays in products reaching patients.
Parker Bioscience Filtration will be examining how to implement a holistic approach to the prevention of Mycoplasma contamination in an upcoming webinar entitled: The Prevention and Control of Mycoplasma Contamination in Bioprocessing which will take place on January 15, 2019, at 3 p.m. London time/10 a.m. New York time.
Here presenters Guy Matthews, global market development manager, and Dr. Carolyn Heslop, technical support group team leader, answer common questions on the threat posed by Mycoplasma contamination and how this can be tackled by biopharmaceutical manufacturers.
“Short-term consequences for a biopharmaceutical manufacturer can include unplanned downtime and lost batches. This can result in the supply of pharmaceutical products to patients being affected. In the long term, there may be financial consequences through a loss of confidence in the manufacturer and a resulting decline in the company’s stock value.”
— Guy Matthews
“As Mycoplasma can infect mammalian cell cultures through adhesion and subsequent fusion to cell membranes, this allows them to exploit the conditions and synthesized molecules provided by the host cell. This means that detection and quarantine procedures must also be implemented around cell lines. Mycoplasma can vary in size and shape from 0.2 microns upwards, have no peptidoglycan cell wall and exhibit pleomorphism (the ability to alter size and shape in relation to environmental conditions). This means that they are capable of penetrating sterilizing grade filtration systems.”
— Dr. Carolyn Heslop
“Start with the basics: employing the standards of Good Laboratory Practice. Considering factors such as the storage and packaging of media, and understanding the nature of the supply chain are all important factors in mitigating the risk of Mycoplasma contamination. Identifying where contamination is likely to originate from and mitigating the risk at the source can prevent problems further on in the process. Gamma irradiation or heat inactivation to eliminate Mycoplasma present on gamma or heat-stable incoming raw materials can be used to guard against contamination. However, not all media components can be heated or subjected to irradiation. Therefore, filtration has a vital role to play in combating contamination during the biopharmaceutical process. Biopharmaceutical manufacturers should consult with their filter suppliers on issues such as filter sizing to ensure that their filtration systems are optimized appropriately."
— Guy Matthews
“In order to effectively control Mycoplasma, the use of a Mycoplasma retentive 0.1 micron filter – such as Parker's PROPOR MR – is recommended. However, as the filter is twice as tight as a standard 0.2 micron sterilizing grade filter, pressure levels in the process can be a major concern. Filters may not function effectively if the flow is too rapid – for instance when pressure peaks occur.”
— Dr Carolyn Heslop
“Biopharmaceutical manufacturers could consider implementing an automated single-use system. This ensures that critical process parameters such as pressure levels can be constantly monitored, ensuring the process stays within the validated process limits. An automated single-use system will also remove the possibility of human error – and give manufacturers more control over the process.”
For more information on the advantages of single-use technology in mitigating the risk of Mycoplasma contamination and how to implement a holistic approach to the prevention of Mycoplasma contamination, register for Parker Bioscience Filtration’s forthcoming webinar: The Prevention and Control of Mycoplasma Contamination in Bioprocessing. The webinar will take place on January 15, 2019, at 3 p.m. London time/10 a.m. New York time.
This post was contributed by Guy Matthews, global market development manager, and Dr Carolyn Heslop, technical support group team leader, at Parker Bioscience Filtration, United Kingdom.
Parker Bioscience Filtration specializes in automating and controlling single-use processes. By integrating sensory and automation technology into a process, a biopharmaceutical manufacturer can control the fluid more effectively, ensuring the quality of the final product.
Process Protection: What Does It Mean to You?
Controlling Supply Chain and Process Risk During Biomanufacturing
What's Stopping you from Automating your Single-Use Process
Many companies, including those in the food and beverage, pharmaceutical, cosmetics, manufacturing and electronics industries, recognize the negative effects on quality created by oil contact with their product during production. Product rejections and consumer safety concerns associated with oil contamination can have broad negative financial and commercial impacts on a company. However, an often overlooked source of oil in compressed air — ambient air — is frequently misunderstood, underestimated or ignored.
In this blog, we’ll examine the effect that ambient oil vapour levels can have on downstream compressed air quality and what to consider when looking for technically oil-free compressed air to ISO8573-1 Class 0 or Class 1 for total oil.
For details on oil vapour testing levels in ambient air, test methods, compliance and other gaseous contaminants of concern, download the full white paper “Oil Vapour in Ambient Air”.
Ambient air is the air we breathe and it’s all around us. It’s also the air that is drawn in by air compressors. Ambient air is made up of approximately 78% nitrogen and 21% oxygen. The remaining 1% contains a mix of argon, carbon, helium and hydrogen as well as a variety of contaminants — oil vapour being one of them. Ambient air is an often overlooked source of contamination that can have a big impact on a compressed air system.
Ambient air quality is directly impacted by air pollution caused by industrial processes such as burning fossil fuels and emissions from vehicle exhaust, oil and gas fields, paints, and solvents.
Oil vapour in ambient air is made up of a combination of hydrocarbons and volatile organic compounds (VOC). Ambient air typically contains between 0.05mg/m3 and 0.5mg/m3 of oil vapor, however, levels can be higher in dense, urban or industrial environments or next to car parks and busy roadways.
These levels may seem negligible, but when it comes to compressed air contamination, we must consider the effect that compressing the air has on the ambient contamination, the amount flowing into the compressed air system, and the time the compressor is operating.
The process of compression, as well as flow rate and time, build the level of oil in the compressed air that travels through a production system — air that eventually finds its way to production equipment, instrumentation, products and packaging materials.
Compression, or pressurizing the compressed air, can significantly increase the volume of oil. The greater the operating pressure, the higher the potential level of oil in the compressed air. This is compounded by the flow rate and time of operation. Compressors are often designed to operate continuously. This means that the concentration of oil continues to multiply in the confined space of the compressed air system. In turn, it will only exit the system at points where the air is released. These exit points are often in areas where the contaminated air comes in contact with product, production equipment or instrumentation. So, what may seem like negligible levels of hydrocarbons and VOC in ambient air, can become a great concern when the same is drawn in and compressed for use in manufacturing.
Once inside the compressed air system, oil vapour will cool and condense, mixing with water in the air. This contamination causes numerous problems to the compressed air storage and distribution system, production equipment and final product leading to:
Due to the financial and commercial impact of contaminated product, many companies specify the use of an oil-free compressor, in the mistaken belief that this will deliver oil-free compressed air to critical applications.
Oil-free compressed air systems are typically installed without downstream purification equipment intended to remove oil, as they are deemed unnecessary accompaniments. While it is true that oil-free compressed air systems will not contribute contamination in the manner that oil lubricated systems will, oil vapour from ambient air remains untreated.
Technically oil-free air, in accordance with ISO8573-1 (international standard for compressed air purity) Class 0 or Class 1 for Total Oil, can only be guaranteed through the proper application of downstream purification equipment. This equipment may include water separators and coalescing filters to remove liquid water and oil, aerosols of water and oil, and solid particulate as well as adsorption filters to treat oil vapour. Compressed air users seeking an oil-free source of air would be wise to consider these precautionary purification steps, whether they are used with oil-lubricated or oil-free compressed air systems.
In order to establish compliance with ISO8573-1 Class 0 or Class 1, the international standards categorizing oil level in compressed air, users must perform tests to assess both oil aerosol and oil vapor presence in their systems. The levels of each phase will combine to establish total oil in the compressed air system.
To conduct the tests, samples of each phase must be drawn through a solvent extraction process and analyzed using gas chromatography (GC) or Fourier transform infrared (FT-IR) technology. The combination of the two methods will provide an accurate reading down to 0.003mg/m3.
While there are other methods for testing oil levels, like Photo Ionisation Detector (PID), these will leave certain compounds undetected. To this end, they should be used for estimation purposes only. GC and FT-IR will provide results that can be related to ISO standards with reliable and complete accuracy.
Parker has recently introduced a new compressed air purification system. The OFAS Oil Free Air System is a fully integrated heatless compressed air dryer and filtration package suitable for use with any compressor type and can be installed in the compressor room or at the point of use. Fitted with a third adsorbent column for oil vapour removal, the OFAS has been third-party validated by Lloyds register to provide ISO 8573-1 Class 0, with respect to total oil from both oil-lubricated and oil free compressors, ensuring the highest quality air at the point of use for critical applications.
Compressed air is vital to any production process. Whether it comes into direct contact with the product or is used to automate a process, a clean, dry reliable compressed air supply is essential. If the compressed air contains oil, the consequences can be high both financially and in terms of brand damage.
For details on oil vapour testing levels in ambient air, test methods, compliance and other gaseous contaminants of concern, download the full white paper "Oil Vapour in Ambient Air".
Seven Myths About Oil-Free Compressors
Why Are Coalescing Filters Installed in Pairs?