A new year is a great time for a shift in direction. This blog tries to be different each time. I cover topics ranging from innovation to technical leadership. I’m always looking for fresh ways of doing things in our industry, in process engineering and business development. And I look for new ways to convey these ideas to the marketplace.
We have a chance for the next decade to be a new roaring ‘20s. Don’t get stuck taking the same routes you’ve always been traveling. Try these approaches for a novel approach to 2020 and beyond:
Adopt a positive mindset and see the opportunities
Its easy to get bogged down when a process is not working or a project is going sideways. Learn to accept – everything from setbacks through to challenges. Turn these diversions from your plan or expectations into opportunities.
Be brave and stick to your guns
Maybe you are the innovator with a new idea of how things should be done. If you are sure about the design or process change, then go ahead and make the change.Remember, to test first and to have all of your facts in place to show technical leadership.
Make room for your own creative projects
No matter your work focus, set aside time for your own projects.Take one hour each morning (for me after yoga) and before you check your e-mails for your personal projects; this will pay off greatly in the long term, on many levels.
Don’t let the pressure or threat of failure or competition hold you back
Be confident in your work and don’t be afraid to try something different. We always learn from our mistakes, and from getting out there and gathering more information. With greater knowledge comes greater confidence.
Be authentic and believe in yourself
Use more of your judgement and less of other’s opinions. As I have written in the past,learning never ends. And if you try to be what other people want of you, instead of being authentic, it can have negative impacts both on your professional life and personal well-being.
Accept that personal progress can take time but perseverance counts
Any goal takes time.As loyal readers already know, I sometimes mention my yoga practice, which includes headstands, shoulder stands, tripod stands, etc. These did not happen overnight. But by persevering and keeping an eye on small moments of personal progress along the way, I was able to stick with it and see greater success long-term.
Let’s get ready for 2020. I’ll continue working on this blog and providing new BHS and AVA technical and innovative insights on, Perlmutter & Idea Development. As you start anew in this fresh decade, I hope you’ll keep reading my blog and my LinkedIn posts. And don’t hesitate to let me know your ideas about technical leadership and other areas of interest for this blog!
One key element of innovation success is taking risks. I’ve recently read two articles where major breakthroughs in human health started with innovation risks. The two stories are a great reminder that we need to step up to challenges and look at the world anew to innovate!
In our first case, from Business Week, a chemical engineer named David Whitlock became interested in biology after a tubby date asked him why her horse rolls in the dirt, even in the cool springtime months before the biting insects have even hatched. Whitlock was curious too. So he started reading scientific papers and came across a “bacteria, found in soil and other natural environments, that derives energy from ammonia rather than organic matter.”
Whitlock’s took risks for his research. In 2009, he moved into his white Dodge Grand Caravan to study the bacteria culled from soil that he theorized could improve skin disorders, hypertension, and other health problems. And even he’ll admit there were some times he really smelled while experimenting with his soil-based concoctions on himself.
Still, his innovation risks led to the ground-breaking discovery that these ammonia-oxidizing bacteria (AOB) can transform sweat into something more useful. His company now generates almost $2.6 million revenue in cosmetic sprays, shampoos and moisturizers. Microbiomes, “commensal, symbiotic and pathogenic microorganisms that literally share our body space” are now the focus of many new products. The third annual Skin Microbiome Congress, for instance, welcomed established brands such as BASF, Bayer, Coty, Merck, Nestlé, L’Occitane, L’Oréal, and Unilever.
The article is a great example of a single researcher’s drive and creativity. He didn’t shy away from the tough stuff in pursuit of innovation.
An Eye-Opening Innovation Risk
A second recent Business Week article is further evidence that it pays to swing for the fences. The article is about manufacturer W.L. Gore & Associates Inc., best known for the waterproof membrane Gore-Tex, and how its willingness to “take more chances” has led to its polymers being used in corneal implants.
An obsession with a polymer called polytetrafluoroethylene, PTFE, led William Gore to his discovery of the lighter and yet stronger expanded ePTFE. The polymer is now not only used in waterproof wear, but also in air purifiers, dental floss, high-tension ropes, and stents and surgical patches.
Yet the company was stagnating as competitors introduced alternatives. Gore needed to get ambitious again. When Anuraag Singh encountered Gopalan Balaji in a lunch line at a corporate event, the two natives of India, where corneal blindness is a major issue, asked whether they couldn’t do more with their company’s polymer.
Enlisting others, their team sought to modify the polymer to be transparent and light bending in the same way that the human cornea tissue is in our eyes. Their first attempts fizzled and were shelved until a new CEO came to Gore and encouraged innovation risks anew.
With new seed funding to learn more from ophthalmologists, rethink the design, and reconsider their material choices, their team came up with a new prototype. As a sidebar, I have to applaud thehands-on discovery involved along the way:
“We love putting prototypes and materials on the table,” Singh told Business Week.“A typical meeting would involve the surgeon and the engineers ‘all kind of hunched over: feeling, touching, poking at things.’”
The result? An artificial cornea that may help to solve a pressing human health problem in developing countries. The plan is for continued research and testing the first implant in humans in 2020 with the goal of bringing it to market in 2026. With cornea tissue damage the 5th leading cause of blindness this innovation risk could have a happy ending.
Ultimately, these two examples are reminders that we need to look around, ask questions, and listen to our communities to come up with ideas. Then we need to take those necessary innovation risks!
So, here we go again…intertwining two seemingly unrelated topics — creativity and eight-limbed ocean dwellers — in one interesting blog.
Over the years, as my readers know, I’ve enjoyed discussing fresh sources of innovation. Today, it’s the octopus.
First some technical details: Octopuses have eight arms, round bodies and bulging bilateral eyes. The 300 species of octopuses live in all the world’s oceans, but prefer warmer, tropical waters. They typically only live between 1 and 2 years, but during that time they like to play.
That leads us to the good stuff: These creative, intelligent creatures can problem solve and are masterful mimics. Some species can even change the texture of their skin to better hunt and evade predators. Plus, they all lack a rigid skeleton, which lets them contort themselves into amazing shapes.
Yet how does a creature that can only see in black and white make these changes? They control special cells just under their skin’s surface — chromatophores — which hold pigment andchange color within milliseconds. Controlled like muscles, these cells can help many octopuses “see” with their arms and learn the patterns, colors, and textures of other animals they want to imitate.
Sy Montgomery, author of The Soul of an Octopus shares, “three-fifths of an octopus’ neurons are not in their brain, but in their arms,” which “suggests that each arm has a mind of its own”. These arms have sensory capabilities (smell and taste) as well as reach, and can even continue to grasp if severed from the body.
Wile. E. Octopus Creativity
The octopus is a living example of the sentiment in my first blog of 2019, Becoming Uncomfortable. The octopus is always exposing itself to new environments and facing predators.With creativity and intelligent problem-solving it succeeds. Just as humans need to put themselves out there and expose themselves to new backgrounds, experiences, and more. We can’t blend in like the octopus, so we have to become uncomfortable, but it’s worth it.
There’s also something we can gain from thinking about the octopuses seeing with their arms. Think how humans might engage differently if we could see with our arms?We’d be sure to look at tasks in a different manner when thinking critically about process.
Finally, let’s consider what we’d do with better camouflage. I don’t mean you should wear a disguise at work! Still, what if you were to try to camouflage your thinking. You too can be a masterful mimic to problem solve or put yourself in the shoes of the client: “I am not the sales engineer but the lead process engineer” or “I am the Director of Capital Purchasing” or “I am the entrepreneur who needs advice for a process solution while spending my own money.”
We’re still stuck with bones, so we can’t morph into all the different shapes this amazing creature can manage. A 600-pound octopus can get through a pathway the diameter of a quarter! Yet, the octopus’s sense of adventure also underlines my suggestion to get out into the world and see what’s going on for a new perspective on process solutions and life in general.
I hope you’ll have some fun with this and think about the octopus next time you want to be creative!
Normally, as my readers know, my blogs cover a wide variety of topics. I like to relate and link seemingly unrelated topics to each other in innovative ways. It keeps our critical thinking faculties sharp! However, this blog deviates from the pattern to share two fresh viewpoints on changes in engineering standards. It’s technical, but important. Science textbooks will need to be rewritten!
It doesn’t happen often, but after a November 2018 vote at the Congress Chamber in the Palace of Versailles, four fundamental units of measure have been redefined. An assembly of metrologists (those who study the science of weights and measures) voted to redefine the International System of Units (SI)’s ampere, kelvin, kilogram, and mole.
These four units join the meter, candela, and second in being defined not in reference to physical artifacts, but in reference to fundamental physical constants. Scientists say redefining these units to be based on a physical constant will make measurements more accurate and stable.
Science students may not be too happy about having to pay for new science textbook editions, but the unanimous vote was followed by a standing ovation by the assembly’s participants from over 60 countries.
Engineering Standards Must Be Correct
The news was followed up by a Wired blog by Rhett Allain, an Associate Professor of Physics at Southeastern Louisiana University. He agreed the “definition-based standard” was a better choice:
There is a new standard in town, and it’s sort of a big deal…It replaces the old definition of the kilogram that didn’t even have a definition. The old kilogram was an actual object. It was a cylinder made of a platinum alloy and it had a mass of 1 kilogram. It was THE kilogram. If you wanted to find the mass, you had to take it out and measure it. You could then use it to make other kilograms.
He was behind the new standard of defining the kilogram using another constant—Planck’s constant (the details are in the Wired story). However, Allain also cautioned that there is a wrong way to define the kilogram. “Unfortunately, I have already seen some very poor explanations of this new definition of the kilogram,” he wrote. His fear, he wrote, was that “these super-simple (and technically wrong) explanations might become very popular.”
For example, he cites an example: “The new definition of the kilogram sets it equal to the mass of 1.4755214 x 1040 photons from a cesium atom.” Of this he notes, “That is so bad. I’ve even seen a diagram with a traditional balance. On one side there is a kilogram mass, on the other side a bunch of photons. Please help; please don’t share that kind of stuff. You might as well just say ‘Oh, hey—the kilogram is now defined by some magical spell.’”
This is an edited version of an article I wrote for The Chemical Engineer. I hope you enjoy this take on automated clarification technologies.
Throughout my career in the solid-liquid separation market space, I have seen some interesting solid-liquid separation solutions. At one melamine resin facility, the slurry was in a formaldehyde process. The operators were wearing masks, opening up a manual plate filter in a room with residential floor fans, to dig out the cake from the paper filter media.
In another case for zeolites, the client had multiple bag filters to clarify the filtrates following a vacuum belt filter. When the filtrates, the final product, remained cloudy, to my surprise, the client decided to add another set of bag filters!
A clarification system is employed after coarse-particle filtration or as a stand-alone system to remove fine particles at low concentrations. These particles are typically less than 5 µm and are in concentrations less than 5% solids down to ppm levels.
Process engineers struggle to clarify process liquids. But there are ways to automate the clarification processes to improve filtration and minimize operator exposure. The cake solids structure and the nature of the process will determine which types of pressure-filtration, automated clarification technologies are best for you.
A candle filter is a pressure vessel filled with tubular filters (called filter candles). A typical filter candle comprises a dip pipe to flow the filtrate and pressurized gas, a perforated core with supporting tie rods, and a filter sock.
As the cake builds during operation, the candle filter’s removal efficiency increases, enabling removal of particles as small as approximately 0.5 μm.
During operation, a feed pump or pressure from the reactor or feed tank forces the slurry into the bottom of the pressure vessel. The solids build up on the outside of the filter sock, while the liquid filtrate flows into the candle, through the registers, and out of the vessel. This process continues until the maximum pressure drop, design cake thickness, minimum flow, or maximum filtration time is reached. The cake is washed to remove impurities and residual mother liquor, and then dried by blowing gas through the cake. Next, low-pressure gas enters the individual candles and expands the filter socks.
This process breaks apart the dry cake, which detaches from the filter sock and falls into the vessel cone. Candle filters are used for thin-cake (5–20 mm) pressure filtration applications. They are best suited for filter cakes that are vertically stable.
Pressure Plate Filters
Like the candle filter, pressure plate filters comprise filter elements contained within a pressure vessel. However, instead of vertical filter candles, the vessel containshorizontal filter plates. These elements are slightly sloped, conical-shaped metal plates that support a coarse-mesh backing screen covered with filter cloth.
An opening in the centre of the plate allows the filtrate to travel between plates and throughout the vessel. The filter cloth can be synthetic, as in the candle filter, or metallic as the cake discharge is by vibration or spinning.
Operation is similar to that of a candle filter. For cake discharge, there are two main designs. In one, two unbalanced motors vibrate the filter plates to dislodge the cake from the filter cloth. In a second design, the plates spin so that the cake can be ‘thrown’ off the plates. Pressure plate filters are used for filtration of cakes up to 75 mm thick.
Sintered Porous Metal Cartridges
Another type of automated clarification technology is based upon sintered porous metal cartridges. These can be used in a variety of process flows such as inside-out filtration. After each cycle, solids are backwashed off the inside of the elements and discharged as a concentrated slurry or wet cake. They can also operate in a conventional outside-in filtration. Porous metal cartridges are used for high temperature applications greater than 200oC where the solids are well-defined hard crystalline shaped.
Filter aids are generally the last resort. Often in clarification applications, the solids are very fine or amorphous, so can be difficult to filter. When filtered, the solids will create a thin, impermeable coating over the filter media and immediately reduce the filtration rate to an unacceptable level. In these difficult cases, filter aid pretreatment can be used to improve filtration properties and efficiently remove the fine solids from the process liquids. The types of filter aid include diatomite, perlite, and cellulose.
In the precoat method, filter aid is used to generate a thin layer of solids on top of the filter media. Once formed, the filter aid cake functions as the primary filter media. Therefore, the filter cloth is no longer the real filter when precoat is used. For that reason, the filter cloth should be as open as possible while still retaining the filter aid material.
The precoat process is achieved by mixing the filter aid into clear liquid or mother filtrate in a precoat tank. This slurry is then recirculated through the filter where the solids are captured by the filter media. The clean filtrate is recirculated back into the precoat tank. The precoat should be thick enough to ensure that the entire media surface is coated but thin enough so that it does not provide significant resistance to filtration.
In body feed filtration applications, the filter aid is blended with the slurry feed either by dosing the concentrated filter aid suspension into the slurry feed with in-line mixing or by mixing the filter aid into the entire slurry batch and maintaining agitation. By adding filter aid into the slurry feed, the resulting filter cake is more porous, allowing higher and longer sustained flow rates. Body feed also helps to restrict solids movement which improves filtrate clarity.
Needless to say, the use of filter aid improves filtration but requires more equipment, more process control, and results in more solids for disposal.
Final Thoughts on Automated Clarification Technologies
How can the process engineer be successful? When confronted with a clarification process, don’t simple throw more bag filters at the problem. Conduct lab testing to analyze the cake structure, filter media, filtration pressure and cake thickness. With the data in hand, you can evaluate the different technologies and design a more reliable and cost-effective clarification process. Find a different approach!
P&IDs are par for the course in process engineering. Recently, I was poring over P&IDs and process planning for several projects. Each project was multinational, multicultural, and extremely complex. For one specialty chemical filtration application, part of a plant expansion in the southern United States, the engineering company is in the Southeast while the existing processes were from the Netherlands and Austria. In another project, with a similar scope, the plant expansion and the engineering company were both in the Northeast U.S., yet the current processes operate all throughout the UK.
As you can imagine, the piping and instrumentation diagrams (P&IDs) had many changes, each shown in a different color —the Christmas Trees of P&IDs.There were extensive e-mail threads of comments and questions and, of course, questions/comments about the comments/questions. Plus, the projects required equally fun conference / video calls accounting for time zone differences, various languages and accents, and varied engineering cultures and operating philosophies. You’ve been in this situation too, I’ll bet.
The discussion, though, is invigorating. The idea exchange goes well beyond solid-liquid separation to encompass types of valves, types of pumps, where to put the pumps, how to handle the solids, operator safety, disposal, and on and on and on.I even had a question about desalination and how to operate the DAF (Dissolved Air Flotation) units (that’s a topic for another blog).
Developing A New Process Path with P & IDs
After one of these calls, I had an “A-Ha” moment about the true value of our plentiful rounds with P&IDs and process. This is where the innovation happens. The P&IDs are idea development in action. This is where we, as I wrote in one of my earlier blogs, clear our path of unknowns.
Anyone who’s read my blog consistently will recognize this is what is excites me about process engineering and all we do in this role. I’ve decided to take my own early 2019 advice and stretch myself in new directions with the birth of “P&ID-Perlmutter Idea Development” which you can find at perlmutter-ideadevelopment.com.
To me, these two sites work together like a candle filter functions better with the right filter sock. I’m excited to see how this idea develops, and eager to see what my readers, colleagues, and fellow bloggers will want to add and change and discuss (after all, it’s a P&IDs and process we’re talking about here).
Readers of my blog, know that I am a big baseball fan and now-retired player due to a bad-hop broken nose years ago. Golf is generally much safer. If you look back, you can see my blogs about juiced baseballs, Moneyball and baseball in Japan. I also write a lot about safety at chemical plants.So, here we go again…let’s talk about baseball data and safety.
This season there has been a lot of talk about foul balls striking and injuring fans and installing netting to protect fans. But, as process engineers, we know that we need to first consider the data before making any decisions. So, let’s get the data and discuss the best way for Major League Baseball to proceed.
Fly, grounder, line drive, pop up or batter hits self
Recorded exit velocity of each hit — blank if not provided
The zone we predicted the foul ball would land in by gauging angles
The zone that the foul ball landed in, confirmed by footage
The zone used for analysis
This data collection was no easy feat. The MLB does not keep this type of statistics, even though baseball is really a numbers game. The team watched the 10 most foul-ball-heavy games this season to gather their findings.
Armed with the baseball data, Choi and her team determined the ball parks with the most foul balls:
MOST FOUL-HEAVY DAY
STADIUM AVERAGE NO. OF FOULS PER GAME
NO. OF FOULS
Camden Yards* 57
Baltimore Orioles vs. Minnesota Twins
PNC Park 57
Pittsburgh Pirates vs. Milwaukee Brewers
Oakland Coliseum 53
Oakland A’s vs. Houston Astros
T-Mobile Park 53
Seattle Mariners vs. Minnesota Twins
Globe Life Park 55
Texas Rangers vs. Toronto Blue Jays
Dodger Stadium 51
Los Angeles Dodgers vs. Arizona Diamondbacks
Miller Park 55
Milwaukee Brewers vs. New York Mets
Citizens Bank Park 53
Philadelphia Phillies vs. Miami Marlins
SunTrust Park 53
Atlanta Braves vs. New York Mets
Yankee Stadium 51
New York Yankees vs. Baltimore Orioles
The team then looked at netted versus non-netted areas as well as the ball velocities.Interestingly enough, they found that almost an equal number of balls went to each area but the balls with the highest velocities went into the unprotected areas.
Choi concludes, “Even with extensive netting, no one will ever be completely safe at a baseball game. But there are ways for MLB to protect its fans from foul balls — particularly in the most dangerous areas of the park.”
What I appreciate most is her observations are based in testing and learning about baseball data!
So, enjoy the World Series and root on your team and as Ernie Banks once said “It’s a beautiful day for a ballgame… Let’s play two!”
One way to be a better leader? Always be thinking about ways to become a better leader. I see lessons about leadership skills in my reading about sports, current events and more. Today, I thought I’d share some examples that have prompted personal leadership insights as I look to constantly develop and embrace change.
First, leadership requires taking full responsibility for the company, project, process or whatever you are leading. What are some examples? Well, whether you like him or not, Tom Brady routinely takes personal responsibility for his actions as well as the actions of his team. Another example is “EK” the 25-year-old coach of the soccer team trapped in the Thai cave for over 3 weeks. He acknowledged his actions and accepted full responsibility even sending notes to the boys’ parents apologizing for having led the team astray.
Secondly, a leader exudes confidence in his abilities and his team’s abilities. Brady is the master of making comebacks and finding a way to win; his confidence transfers to his teammates. EK may have made the biggest misstep of his life but he also exhibited confidence and strength when the team needed it most.
Next, leaders are cool under fire. Leaders set the tone in a crisis and can inspire others. While TV illustrates Brady’s explosive drive on the sidelines, he’s quite calm on the field. Under tense circumstances, EK kept himself and his boys steady until help arrived.When you keep your cool and don’t get rattled as a leader, you can make better and more thoughtful decisions.
Leadership is a Balancing Act
Communication, hard work and knowing the market and the competition are also essential for leaders. Leaders should also put themselves second to their employees as it creates an environment of trust and cooperation.
Brady will put his team first to accomplish a goal — the next Super Bowl win. In the Thai example, EK was the last person out of the cave and even refused food and water for himself, choosing instead to give his rations to the boys. This prioritizing of his team members likely helped EK to command respect and cooperation from his young players.
Finally, leaders also taking time to recharge and find balance. I practice yoga every day and have written about my practice and breathing in this blog. There is, however, no one checklist to follow for achieving balance. What’s most important to you will change depending upon where you are in your career. The balancing act will encompass a leader’s drive for and valuation of knowledge, professional expertise, lifelong learning, relationships, family, community, and openness to self-questioning and to change.
I’d love to read your ideas on leadership and learn how you balance your guiding principles and life pillars. Let me know!
There are may different types of engineer. Recently, I read some interesting articles about defining engineers by their skills and depth of knowledge. This blog asks you to consider, what’s your skill shape: I…T…or Key?
In the 1970’s, companies wanted staff with an I-shaped skill level. What does this mean? I-Shaped Skills reflected a person with a deep (vertical) expertise in one area and practically no experience or knowledge in other areas. This person would typically be known as a specialist. It could be one process, one type of distillation, one type of pump, etc. I remember the days when my customer, Eastman Chemical, had flange specialists, o-ring specialists, vacuum pump specialists. The other large chemical companies, such as Dow Chemical, had similarly focused engineers.
In the 1980s, McKinsey & Company developed the idea of the T-shaped professional. The vertical bar on the T represents strong knowledge in a specific discipline. The horizontal bar represents a wide yet shallow knowledge in other areas. This allows the person to collaborate across other disciplines and acquire new skills or knowledge. Chemical companies have T-shaped engineers such as filtration experts, drying experts, solids handling experts, etc. These engineers can support all types of applications across all of the operations at various sites.
One classic T was Thomas Edison, who wanted the people around him to know a lot of different things. All his prospective employees had to take a test of 150 questions geared toward different jobs and classifications of workers.
Today, the visualization of skills concept has expanded to include the elusive key-shaped professional—a person who has several areas of expertise with varying degrees of depth. The introduction of the key-shaped professional is largely due to the rapid proliferation of technological advances and the cross-disciplinary nature of work. Across industries and professions, the ability to use technology to assimilate and apply information has created a new, broader expectation of the standard skills professionals should have.
As a result, we’re seeing new parallels between skills sought in business and process engineering.The top skills include embracing new technology, understanding data, and thinking critically about that data.
Becoming a Key-Shaped Engineer
So, how do you become a Key-shaped professional? I have made several suggestions in other blogs:
So, now you may ask, how do I describe myself? Early in my career, I was T-shaped with knowledge about solid-liquid separation. As I progressed, I became more of a Key shape with knowledge about varied topics such as centrifugation, drying, solids handling, mixing and other process operations as well as technical business marketing and startups.
I encourage you to think about your own skills shape. It might prompt a learning opportunity, and I’d be happy to help where I can with your transformations.
Filter aid pretreatment can improve filtration properties and efficient removal of fine solids. Whether the filter aids are used in Plate-and-frame filter presses, horizontal and vertical pressure leaf filters, candle or tubular filters, Nutsche filters, or rotary vacuum drum filters, these practical tips can help this part of the process run smoothly.
We typically see diatomite, perlite and cellulose filter aids today. They meet the requirements of a filter aid in that they:
Consist of rigid, complex shaped, discrete particles;
Remain chemically inert and insoluble in the process liquid.
You’ll want to test different approaches to determine the best aid for your process and which of the methods — precoat or body feed — offers the greatest benefits. Once you’ve done so, though, it’s important to keep these troubleshooting tips in mind.
Practical Pointers for Using Filter Aids
Whether the process is precoating or body feeding, the filter aid slurry tank and pump are critical to the operation.
In precoating, the mix tank should be a round, vertical tank with a height twice its diameter. Set the usable volume of the precoat tank at ≈1.25–1.5 times the volume of the filter plus the connecting lines. Use a mixer or agitator with large slow-speed impellers to avoid filter aid degradation and the creation of fines — otherwise you’ll dramatically change the filter aid process filtration.
The precoating pumps almost always are centrifugal pumps because they produce no pulsations to disturb precoat formation and their internal parts usually have hardened surfaces and open impellers to reduce wear. For body feeding, you’ll use positive displacement pumps.
Yet even when the feed tank and pump are correct, several typical issues with filtration/filter-aid systems can arise.
Bleed-through is common where the filter aid is bypassing the filter media. It may stem from mechanical, operational or process causes. Check a couple of mechanical points:
Is the filter medium secured to the filter correctly?
Does the filter medium have a tear or pinholes?
Is the type of filter aid correct for the filter medium mesh size and the particle size distribution of the process solids?
Another issue may be reduced filtration cycles — i.e., the time to reach the maximum pressure drop becomes shorter and shorter. This may occur:
if the cake isn’t being discharged completely, then each new batch has residual solids in the filter, resulting in lower capacities. Increasing precoat height or lengthening cake drying time may help improve cake discharge.
if the precoat doesn’t completely cover the filter medium, then the process solids may begin to blind the medium.
if you’re using body feed, inadequate mixing with the process solids may result in filter medium blinding. This also can happen if the velocity in the filter vessel is too low, which will allow the filter aid to settle out before reaching the filter elements. A bypass at the top of the filter vessel can help keep the solids suspended within the vessel.
On filters with vertical elements, precoat pump flowrate or pressure may cause loss of the precoat from the filter medium, Improper valve sequencing creating a sudden change in the pressure or flowrate may also be to blame. Finally, a mechanical issue with the filter may prompt a pulsation or pressure change that impacts the cake structure.
Apply Filter Aids Wisely
Employing filter aids to help filtration is tricky; most process operations try to eliminate or minimize their use. However, sometimes they are unavoidable.
To succeed with filter aids, a process engineer should take three essential steps:
Conduct lab testing to examine the filtration operation (vacuum or pressure), cake thickness, filter aid quantities, filter medium and other parameters that are crucial to the process design;
Ensure correct mechanical design to provide optimum precoat or body feed handling and distribution; and
Arrange for operator training on the filtration technology as well as on filter aid operation.
This blog is an edited version of an article I co-authored with Garrett Bergquist, BHS-Sonthofen Inc. for Chemical Processing.