Optimizing downstream final drying

Every year I look forward to attending AICHE, learning from peers, and sharing what knowledge I’ve gained in the past year. COVID-19 pushed us to meet virtually this year. Still, I was pleased to continue to share my talk on BHS-Sonthofen Inc.’s continuum approach to optimizing downstream final drying with upstream solid-liquid filtration. I thought I’d offer a recap here for those who missed the online event.

Most often when analyzing a new process development approach, engineers take a “silo” approach and look at each step independently. I suggest that by taking a holistic approach and looking at each step not individually but as a continuum, the process solution becomes much more efficient. I highlighted my perspective with data showing how to balance each of process steps for maximum efficiency.

My discussion of process filtration and optimizing downstream final drying centered on a specialty chemical process that has crystals in a methanol slurry which must be filtered, washed, dewatered and then dried. In looking to expand the existing process our objectives were to:

  • Migrate to continuous operation from batch operation
  • Maximize solid-liquid filtration performance
  • Achieve low wash ratios for minimum wash media consumption
  • Accomplish lowest possible residual moisture in discharged filter cake 
  • Reach final moisture of <1.0% 

Testing a Continuum Approach to Optimizing Final Drying

The standard approach is to optimize the solid-liquid filtration step with maximum washing and pre-drying efficiency, Then, with this information we’d optimize the downstream drying. However, the client wanted us to look at the process as a continuum from solid-liquid filtration through cake washing and dewatering to final drying. 

Our testing started at BHS-Sonthofen in Charlotte labs with our Pocket Leaf Filter. Starting with the slurry, we tested for cake thickness, pressure filtration, filter media, cake washing and drying and discharge. 

The flux rate of less than two minutes at @ 200 kg DS/m2/hour) indicated this process was suitable for continuous operation. The cake drying moisture content, varying between 11 – 30%, was another positive indicator for an integrated approach.

optimizing downstream final drying
Example results from the RPF testing

Our lab testing of the slurry led us to recommend a continuous approach using the BHS Rotary Pressure Filter, which conducts pressures, cake watering, dewatering, and cake discharge all, continuously, in a slowly-rotating sealed drum. In testing for this client we achieved:

  • Media = 14 micron and a cake thickness of 25 mm 
  • Desired filtration times and filtrate quality
  • Efficient wash ratios of 0.7 to 1.2 kg MeOH/kg DS
  • Moisture content varying between 11 – 30% based upon the nitrogen for blowing for drying 

Based on the moisture of 11%, we sized the Rotary Pressure Filter filtration area at 2.88 m2 with a nitrogen solvent recovery package to reduce the nitrogen usage. This led to the next step in the integrated process: looking at the dryers.

Optimization testing of AVA dryer

BHS Sonthofen last year acquired AVA dryer, so we turned to their vertical conical dryer for testing. This dryer’s cleanable, contained design conveys solids gently down and out, which was useful for this project’s specialty chemicals.

In pilot testing in Munich, Germany, we were able to determine what moisture level to use out of the pressure filter to get the best continuous approach to final drying. We initially designed a 2.88 m2 with 11% moisture, which led to a dryer of 1.93 m3 and a dryer cycle time of 35 minutes. That system would have cost the client $2 million. 

However, our testing optimized the design to increase moisture out of a smaller filter and use a larger dryer for longer. This saved $500,000 on the total system.

The Continuous Optimized Design

  • Filter Size: 1.44 m2 with 30% moisture using 200 m3/hr N2 + Vacuum
  • Dryer Size: 3.0 m3  
  • Dryer Cycle Time: 60 minutes 
  • Total System Budget Price: $1.5 million 

optimizing downstream final drying
The optimized design

The optimized system with a continuum approach resulted in operational energy and nitrogen savings as well as lower capital and installation costs for a more reliable process. 

I’d have liked to answer your questions about this approach in person. Still, I’d be happy to hear your thoughts. Contact me today!


final drying

Benefits of a Continuum Approach to Optimizing Final Drying 

Screen Shot 2019-07-17 at 11.41.29 AM

 

As we announced in March, BHS has acquired AVA-GmbH. The AVA technologies provide for turbulent mixing, reacting and drying of wet cakes as well as powders and process slurries. The vertical and horizontal technologies are vacuum or atmospheric, batch and continuous, for final drying to “bone-dry” powders. They are an essential part of our “Continuum Approach.” 

What do I mean by that? This blog briefly reviews our first ground-breaking study showing the benefits of a “Continuum Approach” to final drying and upstream solid-liquid filtration, cake washing and dewatering.  

Most often when analyzing a new process development approach, engineers take a “silo” approach and look at each step independently.  Our article illustrates that by taking a holistic approach and looking at each step not individually but as a continuum, the process solution becomes much more efficient.  

In the manufacturing of the specialty chemical involved, the crystals coming from the reactor in a methanol slurry had to be filtered, washed and dewatered and then dried to a final moisture of less than 1.0 (<1.0 %).  The standard approach would be to first look at the solid-liquid filtration step and optimize this step for the maximum washing and drying efficiency. Then, with this information, we’d optimize the downstream drying.  The operating company, however, took a different approach and looked at the process as a continuum from solid-liquid filtration through cake washing and dewatering to final drying. The Continuum Approach” resulted in operational energy and nitrogen savings as well as lower capital and installation costs for a more efficient and reliable process.  

You can read the full technical article, but the overall result was a 50% decrease in the filtration area, elimination of a nitrogen recovery system with a 30 minute increase in batch drying time at a lower temperature for better product quality.

Contact me to optimize your current drying and filtration process. Let’s get more efficient together!

 


culinary innovation

Quarantine-Inspired Culinary Innovation

culinary innovation
This is a difficult moment in the world. Maybe you know someone that has been impacted by or struggled with COVID-19. We have all seen businesses coming to a halt and our daily lives upended. My heart goes out to everyone who has been impacted. For some, cooking is a way to show love. So, I thought I’d share some of my quarantine-inspired culinary innovations.
If you’re working from home, you have begun cooking more. I know that I have! Let me share some stories about my cooking as well as companies that innovated to be nimble in the face of the current situation.
My readers know that I exercise, run, and practice yoga. What you may not know is that I am also a good cook. As I am home more and not traveling, I have returned to cooking seafood, tandoori, Spanish, French and other dishes. You can see some of my culinary innovations in this slide show. These are the best ones. Some, I must admit, did not warrant a photo. But we’re always learning.    

culinary innovation
Cooking salmon and veg with a 45-year-old wok!

Culinary Innovation and Agility

While I’ve been innovating in my home kitchen, companies have been innovative in finding ways to meet consumer needs. Let me give you some examples.
King Arthur, a 230-year-old flour company, ramped up production to meet the demands of a baking renaissance. Their flour sales more than tripled as the public seemed to reach a collective understanding that baking and self-reliance was just the thing to help while staying at home. Grocery stores saw increased demand, so King Arthur needed to change their packaging lines to produce more. What did they do? The company innovated and swiftly designed a new plastic pouch that could handle two, five or ten pounds of flour. Within weeks King Arthur was able to increase its packaging processes to add over 1 million bags of flour to inventory.
For another example of culinary innovation during COVID-19, let’s look to Milkrun. The company works with farmers to deliver their products direct to consumers.  This local food delivery service in Portland, Oregon, would normally distribute to restaurants, school districts, coffee shops, etc. However, in a few short weeks, this business disappeared. Milkrun needed to combat two challenges to local food systems to change the business situation: inefficient distribution and low farmer pay. They made changes and developed innovative packaging for items such as sheep’s milk and fruits, so that now they can distribute directly to consumers. Now they’re expanding to Seattle as well as Austin, Denver, Detroit, New York.
Gotham Greens is a fresh food company that builds and operates sustainable greenhouses in cities across America. They grow year-round to supply local produce. Their greenhouses are advanced data-driven, climate-controlled facilities with the highest-yielding farms around. They use less energy, less land, and less water than other farming techniques. Plus, innovative advancements in machine learning and data analysis allow for monitoring of crop health and progress. Yet when restaurants shut down inside dining, the company’s business changed overnight. All the major restaurant clients called to suspend orders. On the other hand, the CEO’s phone “was buzzing off the hook from the largest supermarkets saying can you run extra trucks.” The company upped its planting and production to meet the need. 

Adaptive Processes & Teamwork

These stories of food company agility remind us of the importance of flexibility in business. Innovating new approaches can help with business differentiation. But business also needs to have a solid foundation to be able to pivot quickly in times of crisis. Strong leadership and teamwork can make all the difference.
While cooking is fun, we all miss restaurants and their chefs, bartenders, owners, wait staff, and other employees. I’m sure, like me, you long for and hope to dine in again with them soon. In the meantime, send me your food pictures, recipes, and cooking adventures. I’d love to learn about your culinary inventions during quarantine and beyond.


Changing from Batch to Continuous Processing

batch to continuous processing
Our approaches to process engineering must always be evolving. Otherwise, we’ll never grow and innovate. Recently, I contributed a feature to The Chemical Engineer on making the change from batch to continuous processing. Here's an edited version of that article for my loyal blog readers. 
As there is a push to become more efficient, many process industries have begun thinking about continuous processing. Many specialty and fine chemical operations are batch operated. It is easy and typically uses filter presses, vacuum nutsche filters, filter-dryers, plate and leaf filters, and batch centrifuges. 
Yet batch processing significantly lacks flexibility in scaling capacity, and typically requires larger manufacturing footprints and less efficient use of space. So, I’ve been seeing more of a shift from batch to continuous processing. 
In my career, I’ve helped engineers move to continuous operations for such applications in pharma and biochemical, specialty polymers, starch and cellulose, aromatic acids and fly ash wetting.
Why? In continuous processes: 

  • a filter is typically one-third the size of a batch filter
  • the process can increase yield and optimize quality
  • there are fewer reslurry/holding/buffer tanks
  • transfer pumps can be eliminated
  • complications from solids handling can be minimized
  • less agitation is used (which can impact crystal size and fines generation)
  • it can be easier to maintain constant flows, pressures and temperatures

Applications of Continuous Processing

In the article, I shared several examples of continuous processing applications in my career. I’ll recap a couple of them here too.
In a specialty chemical polymer application, a client wanted to transition to continuous processing to eliminate solids handling and reslurry tanks. Eliminating the liquid ring vacuum pump required for vacuum filtration would also cut energy costs. At BHS Filtration, we did lab and pilot testing to determine the rotary pressure filter was the best option.The continuous pressure filter saw a 16% increase in filtration rate; maintaining the temperature at -5oC resulted in a higher capacity. Secondly, we saw a more efficient washing due to less cake cracking in the thin cake (5 mm) as compared with 150 mm (6-inch) cake. 
For a pharmaceutical client, BHS was involved with a transition to fully-automated continuous processing in extracting phospholipids from egg yolk for preparation as a pet food additive. After consulting with the client and testing, the choice was a continuous-indexing vacuum belt filter for vacuum filtration, cake washing, and dewatering of the cake. The technology is based upon fixed vacuum trays, a continuously feeding slurry system, and indexing or stepwise movement of the filter media. In practical terms, the operational features of the belt filter can be viewed as a series of Buchner funnels. Making that change to the filter validated, as a GMP installation, for pharmaceutical production has increased the yield of the phospholipids by 3–5%. 
 In doing this kind of work, we’ve run into different challenges. We’ve been reminded that process scale matters and what works in the lab may not work in the plant. We’ve seen the need to silo both batch and continuous processes in the same line as a continuum. We’ve been reminded of the need to understand how one upstream decision will impact downstream processes.
We must also remember making the transition from batch to continuous processing requires more than just new equipment. The entire manufacturing operation and the mindset of staff need transformed. 
Process engineers have many choices to transition to a continuous operation. Continuous can be more challenging, but the benefits are there. Just be ready for some unexpected consequences along the way, and always test, test, test!
Of course, if you want to read the entire article, and I hope you will, it’s available! I’d be happy to discuss any of the ideas or possible applications of these insights with you. Reach out to me today!
 


business travel

Road Warrior's First Business Travel after 96 Days    

business travel
Photo by Sheila on Pexels.com

First, let me say that in these challenging times, we all must be diligent in our approaches to our business and personal lives.  My heart goes out to everyone who has been impacted by COVID-19.  To help in my own way, I wanted to offer my recent experience with business travel.
Precautions during the pandemic saw me staying put for the longest stretch of time without travel in over 35 years. Of course, it was good to be home. But the time came to get out and see customers again. My first trip was to Appleton, Wisconsin to visit a customer that I have known for several years for a project that may be funded in the 3rd Q. I thought I would share my experience.
The different travel experience started with packing. I began with all my protective gear. Two N95 masks, two disposable masks, two bandanas (Carolina Panther and The Dead & Company) and one infrared thermometer. Next, what cleaning supplies did I need?  Disinfectant wipes as well as a 12 ounce hand sanitizer; TSA will allow this exception. Finally, sealed googles to fit over my glasses to be used in the airport and airplane. The sealed googles are recommended to help you avoid touching your eyes or face.
Business travel
For the hotel it’s recommended to bring along your own pillowcases. So I packed two. In case the hotel gym is closed I bring along my yoga mat, yoga workout clothes, running shoes and my running clothes. I also throw in my running wind-breaker just in case the weather is a little cooler or rainy.
On the customer visit, I need steel-toed safety shoes and safely glasses. Add those to the pack! Finally, I get to my regular clothes. In the end, a pack that normally takes less than 30 minutes, required 2+ hours and a lot of discussions.
At the airport, with no shuttle buses for long-distance parking, all cars are in the parking deck. Finding a space was another challenge. Once this was accomplished, the TSA checkout point required more time and more space. Finally, the airport and airplane were relatively easy.  The American Airlines “concierge” team was very happy to see me.
Upon landing, the car rental facility also was easy and there were large stickers on each car indicating “cleaned and sealed.” The hotel was also following CDC guidelines with masks, social distancing, cleanliness, etc. So, drinks and dinners in the hotel bar for two nights were fun again. These interactions with the staff and other business travelers are always an entertaining part of business travel.  
As for the business, the visit and meetings were successful. We all wore masks; my temperature was checked. Our lunch was in a large conference room and followed all of the social distancing protocols.  
Oh, one more point. No elevators. I walked every staircase. It’s another thing to keep in mind when you're packing.
So, now I am back “on the road again” (I think that this is a song?) and hopefully to a healthy and successful remainder of 2020. Let me know how you all are doing! What changes have you made to your business travel practices? I can’t wait to see you at the next hotel bar for drinks and dinner.
Stay safe and take care. By having concerns and respect for your friends, families, colleagues, and strangers, we will all make the world a better place.