Clear thinking about automated clarification technologies

automated clarification technologies
Photo by SplitShire on Pexels.com

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.

Candle Filters

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 

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 and Process Evolution

P&IDs and Process

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).

Troubleshooting Filter Aids and Filtration Systems

 

filter aids
Cellulose filter: Imerys Filtration Minerals Inc.

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;
  • Form a permeable, stable, incompressible filter cake;
  • Remove fine solids at high flow rates; and
  • 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? 
  • Is the pump working correctly (flow, pressure, etc.)? 
  • Is the proper amount of filter aid being added?

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:

  1. 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;
  2. Ensure correct mechanical design to provide optimum precoat or body feed handling and distribution; and
  3. 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.

Summer Workplace Safety & Testing Assumptions

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Summer is here! That means swimming, barbecues, and watermelon. I’ve got to admit, though, I’ll be looking at watermelons a lot differently this season. 

Recently, I came across a Black & Veatch video illustrating the importance of wearing your hardhat. They did it by demonstrating structural bolt falling from 20 and 30 feet onto a watermelon. 

While physics is not my primary background, I thought it would be interesting to share Rhett Allain’s discussion of the video’s science.

Allain notes he’s skeptical of the video’s claim that the one-pound piece will have an impact force of about 2,000 pounds when it collides after falling 20 feet. He notes “it’s really difficult to calculate the impact force for a couple of reasons”: impact force is typically not constant plus impact force depends on the stopping distance. 

He suggests instead that the falling bolt problem is a “perfect situation in which to use the work-energy principle.” He goes on to discuss the many considerations such as the one pound bolt falling its distance, making contact with the watermelon and still moving some distance, and the backward-pushing force on the bolt. He puts it all together in a work-energy equation:

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Then he considers impact force, and tries to determine why the bolt dropped from 30 feet instead of 20 feet smashes through the watermelon. He notes, “Honestly, I have no idea where they are getting their values for this video. (They probably need a good science consultant.)”

Clearly, in the video, the melon breaks. Its structural integrity is disrupted and it falls apart. It’s a gooey mess, and no one wants to think of the same thing happening to their head.

Allain points out also that a hard hat will increase impact force so that “if the bolt hits the hard hat and stops over a shorter distance, this would produce a higher average force.” Yet he also notes, “the hard hat does do one thing that’s very nice. Since the hat has a rigid surface, it distributes the impact force over a larger area, which reduces the impact pressure. Lower pressure means there is less chance that the bolt will penetrate your head.”

Ah, what a relief! Even if you don’t get the physics.

Key Takeaway

Ultimately, this video and Allain’s discussion had me thinking again about the importance of workplace safety. At the same time, Allain’s questioning the science demonstrated reminds me of my consistent warning against assumptions. We need to always be testing our thinking, whether it’s about filtration technology or busting watermelons. Be safe this summer!

Removing Catalyst Fines From Raney Nickel Catalyst Reactions

 

Raney nickel catalysts
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Whether you call it Raney nickel or Raney mud, this alloy of aluminum and nickel is a reagent common to many organic processes. Currently, most Raney nickel catalyst slurries are clarified with the use of manual plate or nutsche filters, bag filters, or cartridge filters. 

Yet any of these approaches require manual operations for cake discharge and cleaning between batches or campaigns. At the same time, they accrue high labor, maintenance and disposal costs  and  expose operators and the environment to toxic and hazardous solvents, solids and contaminated filter tools.  

BHS developed a more contained, cost-effective approach using batch-operated, pressure-filtration systems candle filters. 

A Candle Filter Primer

A candle filter is a pressure vessel filled with tubular filters called candles. The candle is comprised of a filtrate pipe, a perforated core with supporting tie rods, and a filter sock.

The filtrate pipe runs the length of the candle and ensures high liquid flow, as well as maximum distribution of the gas during cake discharge. The tie rods create an annular space between the filter sock and the perforated core, which helps maintain a low pressure drop during operation and promotes efficient expansion of the filter sock during cake discharge. The filter sock, made of various synthetic materials, is installed over the candle and can remove particles smaller than 1 micron (μm).

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, pressure from the reactor 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 filtration time is reached. 

For concentrated cake discharge, low-pressure gas enters in the reverse direction through the registers and into the individual candles and expands the filter socks. This process breaks apart the cake, which detaches from the filter sock and falls into the vessel cone. The cake is then discharged as a concentrated slurry. 

Raney Nickel Catalyst with Candle Filters for Slurry Discharge

In this application, the current process after the reactor is gravity separation, hydrocyclones and then followed with cartridges and bag filters.  The specification for the process liquid (diamine and water) is less than 3 ppm catalyst.  This recovery process was inefficient and exposes the operators to the diamine and catalysts creating a safety hazard.  The average particle size is 2 um and amorphous crystals.   

Lab testing and pilot testing was conducted to determine a processing scheme that eliminates solvent exposure, reduces the maintenance and operation requirements of the current scheme and recovers the catalyst to less than 3 ppm.  The final design was a BHS slurry-discharge candle filter with 19 m2 of filtration area. 

Candle Filters for Raney nickel Slurry Discharge

BHS developed this approach working with a client whose process after the reactor included gravity separation, hydrocyclones, then followed with cartridges and bag filters. The specification for the process liquid (diamine and water) was less than 3 ppm catalyst. The average particle size was 2 um and amorphous crystals. Yet, this recovery process was inefficient and exposed operators to the diamine and catalysts, which created a safety hazard.  

BHS conducted lab  and pilot testing to determine a processing scheme that eliminated solvent exposure, reduced maintenance and operation requirements, and recovered the catalyst to less than 3 ppm. The final design was a BHS slurry-discharge candle filter with 19 m2 of filtration area. Learn more about this application in this article.

Inventive Filtration Technologies for Palladium Recovery 

 

Palladium Recovery
Palladium image source

Many times we encounter an “if it ain’t broke don’t fix it,” mentality. Process engineers in particular run up against this constantly. Yet, when it comes to palladium recovery, we’ve seen some strong results from taking an inventive approach to the filtration technologies uses. Currently, in recovering palladium catalysts the slurries are clarified with the use of filter presses, manual plate or nutsche filters, bag filters, or cartridge filters.  

All of these require manual operations for cake discharge and cleaning between batches or campaigns. Other drawback include: 

  • high labor and maintenance costs
  • high disposal costs 
  • exposure of the operators to toxic and hazardous solvents and solids 
  • environmental impact of used and contaminated filter cloth, bag filters and filter cartridges.  

A new approach developed by BHS uses Pressure Plate Filters, which are batch-operated, pressure-filtration systems. Here’s what’s involved.

Pressure Plate Filtration SystemsScreen Shot 2019-01-14 at 3.13.55 PM.png

Pressure plate filters are comprised of filter plates, contained within a pressure vessel. The vessel contains the circular horizontal filter plates in a plate stack. The slightly sloped plates are conical-shaped metal that support a coarse-mesh backing screen covered with filter cloth. An opening in the center of the plate allows the filtrate to travel between plates and out of the vessel. 

The slurry enters the bottom of the vessel and is pumped upward. The solids build up between the plates, while the liquid flows through the core of the filter plates and exits from the top of the vessel. The cake is then washed and dried. Two unbalance motors vibrate the filter plates to dislodge the cake from the filter cloth so it can be discharged. 

Pressure plate filters are used for filtration of cakes greater than 20 mm thick. They are selected for cakes that are stable horizontally because of the orientation of the plates. 

Palladium Catalyst Filtration, Washing and Drying 

There are many choices of technologies, but we’ve found pressure plate filters provide higher quality filtration. In one application, manual filter presses were used to recover and reuse the palladium catalyst. The filter presses exposed the operators to the process and had inefficient washing and drying. The process had a very short cycle of 4 hours per batch.

However, when the BHS pressure plate filter technology was implemented, the filtration, two-step cake washing, nitrogen blow drying and cake discharge were all completed in less than 4 hours with full containment.  Read the full article to learn more.

Changing it Up with Mixer-Dryer-Reactor Acquisition

 

filtration technology
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Starting off 2019, I talked about push pushing ourselves personally and professionally to embrace change. Well, I’m a man of my word, and I’m proud to announce a big change in filtration technology at BHS-Sonthofen GmbH. We’re looking at 2019 as a year of growth, starting with the acquisition of the internationally active AVA-GmbH technology company.

AVA, based just outside of Munich, Germany, has 25+ years under its belt producing innovative machines and efficient processes for any industry. They tackle mixing, drying, reacting, granulating, sterilizing, evaporating, humidifying, and homogenizing to combine engineering expertise and project management know-how to provide “tailor-made solutions from a single source.”

AVA’s product portfolio is a perfect fit with BHS. Having already cooperated with them on joint projects in the past, we can be sure that our company is only strengthened by this move.

In addressing the sale, Dennis Kemmann, Managing Director of BHS-Sonthofen GmbH was enthusiastic about the opportunity to combine our products to have an “even more comprehensive offering in all of our chemical, pharmaceutical and other markets.” 

Expanding Process Filtration Technology Technologies

BHS’s latest newsletter looks at the pairing in more particular applications. You can read more about selecting AVA Vertical or Horizontal Mixer-Dryers for Batch of or Continuous Operations. The goal is a streamlined approach handling as many processes as possible in one unit to curtail investment and process costs. 

Three of AVA’s multipurpose process machines are presented as possibilities to cover the vast majority of the application spectrum of the powder and granule processing industry:

  • AVA Vertical mixer-dryers for batch operation
  • AVA Horizontal mixer-dryers for batch operation
  • AVA Horizontal mixer-dryers for continuous operation

The newsletter also mentions the AVA test center in Germany, which allows customers to scale up from 15 – 90 liter batch mixer-dryer to full scale batch and continuous operations with full scale-up reports and drying curves issued after testing. The US test center in Charlotte, North Carolina will be completed in 4Q, 2019.

Ultimately, the AVA acquisition is good news for current and prospective clients. This change means more innovative process engineering solutions as well as an expanded team to support our customers. The combination of BHS and AVA systems will provide important process benefits for turnkey projects for our clients worldwide. Let me know what we can do for you!

Novel Filtration Technologies for Pharmaceutical Hydrogenation

pharmaceutical hydrogenation
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When it comes to removing catalyst fines from pharmaceutical hydrogenation reactions, BHS Filtration has come up with a novel approach.

Currently, most hydrogenation slurries are clarified with the use of manual plate or nutsche filters, bag filters, or cartridge filters. All of these require manual operations for cake discharge and cleaning between batches or campaigns. At the same time, these units suffer from high labor, maintenance and disposal costs as well as the exposure of the operators and the environment to toxic and hazardous solvents and solids, used and contaminated filter cloth, bag filters, and filter cartridges.  

A new approach uses candle filters which are batch-operated, pressure-filtration systems.

Understanding Candle Filters

A candle filter is a pressure vessel filled with tubular filters called candles. The candle is comprised of:

  • filtrate pipe —  runs the length of the candle and ensures high liquid flow, as well as maximum distribution of the gas during cake discharge.
  • perforated core with supporting tie rods —  the tie rods create an annular space between the filter sock and the perforated core, which helps to maintain a low pressure drop during operation and promotes efficient expansion of the filter sock during cake discharge
  • filter sock — installed over the candle, and made of various synthetic materials, the filter sock is capable of removing particles smaller than 1 micron (μm). As the cake builds during operation, the candle filter’s removal efficiency increases, enabling removal of particles as small as approximately 0.5 μm.

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Candle Filter in Action

During operation, pressure from the reactor 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 filtration time is reached. The cake is then washed to remove impurities and residual mother liquor. Finally, the cake is dried. 

For cake discharge, low-pressure gas enters in the reverse direction through the registers and into 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. The cake can also be discharged as a concentrated slurry. 

Pharmaceutical Hydrogenation Application 

In the pharmaceutical catalytic hydrogenation application, the current process after the reactor is metal bag filters for slurry discharge into manual nutsche “clamshell” filters for vacuum filtration and drying.  The process was time-consuming and required handling of liquids and solids including final “manual dig out” of the filters.  The process solvent was tetrahydrofuran (THF) and ethanol.

Lab testing was conducted to develop a new, one-step process for filtration and drying.  The BHS candle filters with pharma designed candles and cGMP compliance allowed for a revamp of the operation with two filters, one-on/one-off for continuous operation.  Read the full article and let me know what you think!

Application of Separation Techniques & Full Containment

application of separation techniques
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Process engineers devote their time to finding the appropriate application of separation techniques. There’s need for effective solid-liquid separation, cake washing, and drying steps across industries. In many chemical and pharmaceutical processes, the production operations are further complicated by the nature of the process, especially if the process is air-sensitive or toxic.  

The solid-liquid separation step may be accomplished by pressure, vacuum, or centrifugation in a batch or continuous mode. In this step, further choices need to be made regarding the type of filter media and the thickness of the cake or the cake depth during which the separation occurs. To optimize the production process, I’ve found value in thin-cake (2-25 mm) pressure separation technology for full containment, no residual heel.

Importance of Thin-Cake Filtration

Thin-cake solid-liquid separation can be defined as the formation of a cake in the 2-20 mm thickness range.  In this range, cake compressibility becomes less important in the cake building stage of a separation process.  Compressible cakes can be better handled at thinner cake depths and higher pressures. 

For example, an amorphous crystal that does not centrifuge well or requires long filtration times on Nutsche Filter-Dryers can be filtered at 45 psig with a cake thickness of 2 – 3 mm.  Thin-cakes also lend themselves to more effective washing and drying as there is less of a chance of channeling and the mechanism of “plug-flow” of liquids or gases is enhanced.

Impacting Filtration Performance

There are several parameters that can impact filtration performance:

  • Filtration pressure
  • Temperature
  • Particle size/Particle size distribution
  • Particle shape
  • Cake washing
  • Drying of the filter cake.

BHS’s Autopress technology can conduct filtration, cake washing, pressure and vacuum drying all in a contained environment. Cake discharge is complete. There is no residual liquid or solid heel, which is an important benefit for air-sensitive and toxic products.

Application of filtration techniques
Filter plate

Understanding Autopress Technology

This fully enclosed filter press, with circular filter plates, allows flow in forward and reverse directions. The filter plates (which can use synthetic or metal media) are contained in pressurized filter housing with a gas-inflated membrane sealing the annular space. Thus, all operations are contained from full vacuum to 150 psig.  

The operation of the AP Filter begins with slurry filling to form thin filter cakes of typically 5 – 25 mm thickness.  Pressure filtration continues operating up to 8 barg.  The cake can then be mechanically compressed to eliminate cracking to ensure maximum washing efficiency in the forward or reverse direction.  Finally, the cake can be pre-dried or fully dried either by vacuum or blowing gas through the cake. Gentle drying without agitation or tumbling is especially important for fragile crystals and thixotropic cakes.  Elastomeric knives sequentially and automatically discharge the circular cakes after which the filter begins a new cycle. 

Read more about this topic in an article I wrote for PharmaChem. My take-away is that with close collaboration between the client and the vendor, we can do the kind of creative problem-solving that applies the separation technique needed to achieve production objectives.

Busyness versus Business and Chemical Engineering Action

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My first blog of 2018 talked about the “speed” of the world and recommended slowing down and reflecting. Well, here’s some free chemical engineering advice as the year draws to a close: It’s important to take the time to review facts and data, analyze decisions, gather inspiration from many sources, and finally proceed with definite actions. Still, you’ll need to be ready to change, as things will come at you at “breakneck speed.”  

In my out-of-the-box way of thinking, I’m going to relate these ideas to the World Cup — Congratulations to France! During the big tournament of the big game in summer 2018, there was a lot of discussion about penalty kicks. 

Bradley Staats discussed them in the Wall Street Journal article “Don’t Simply Dive into Action:  Think.” He looked at various research sources and concluded that “the goalie’s best strategy may be not to move at all.”  At the same time, surveyed goalies have said that they would regret allowing a goal more if they stayed in the center (rather than diving left or right).  This impulse reflects an “action bias.” The idea that doing nothing could be the best strategy for goalies or businesses is seldom discussed.  

Action Bias in Chemical Engineering

chemical engineering advice
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In the world of chemical engineering, when looking at a problem, we are all taught to gather more data, do more testing, investigate more research, get more sources, etc.  And yes, sometimes this is the best strategy when coming across a problem that is new to the plant or to the specific process.  However, there are many different thoughts on this topic from Sherlock Holmes who employs occasional silence and distancing for problem solving to Thomas Watson, longtime CEO of IBM who would tell his salespeople “the trouble with everyone is that we do not think enough…knowledge is the result of thought.”

So, what is the answer?  As we sit at our computers and study the data, we all debate with ourselves whether to take a short walk or brainstorm for 5 minutes.  As the title of the blog states, busyness does not lead to business or to learning.  So, as an engineer, I suggest the brainstorm approach and thinking.  For vendors and sales people too, the tendency is for action.  But, even for sales people, thinking and slowing down to develop the correct approach is critical to success.

My chemical engineering advice is to avoid acting just to show “action.” Instead, take some time to think.  We may have to change Notre Dame Football coach Frank Leahy’s quote to read instead: “when the going gets tough, the tough get thinking.”  Let me know your ideas.