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4 Questions on Distillation: Effectively remove volatiles and solvents

Posted on August 11, 2020

4 Questions on Distillation: Effectively remove volatiles and solvents

 

In the latest issue of Cannabis Business Times, Dean Segal, vice president of sales and marketing for Pope Scientific, explains why it’s important and how to effectively remove volatiles and solvents prior to, and early in the distillation process to improve yield and quality.

1. Why does removing volatiles before the first distillation pass matter so much?

The goal of the first distillation pass is to remove as many of the terpenes as possible. If these are removed well in pass 1, it will allow for a higher performance during pass 2, with less flashing and greater vacuum, throughput, purity, yield and clarity. However, if the feed to pass 1 also contains leftover solvent—typically ethanol—it weakens the overall operating vacuum, (no matter the type of vacuum pumps or how large they are), leading to less terpene removal. This has a spillover effect because pass 2 is burdened with more terpenes in the feed, diminishing the above-mentioned performance and results of this pass. It’s best to have much less than 0.5% solvent in the pass 1 feed.

2. But if decarboxylation is performed just before distilling, doesn’t that take care of the issue?

Many believe if decarboxylation is performed just prior to distillation, the typical temperature (approximately 130°C) of this intermediate step will drive off all remaining ethanol from the evaporation process following winterization. However, ethanol, though it boils at 78°C in its pure form, also has binding forces with materials such as cannabinoids, which make it harder to drive off. Often, more remains than might be expected.

3. So, what can be done to improve solvent removal?

If a rotary evaporator (rotovap) is used for evaporating at 60°C with a typical rotovap vacuum pump, or if a falling film still was used with a single pass, residual ethanol can remain at 3% to 8%, and decarbing may still result in 1% to 3% ethanol in the pass 1 feed, which is too much. If rotovaping, increase the temperature to at least 90°C for the final hour. If using falling film, it needs further evaporation. Another approach is to plan a three-pass distillation: solvent pass, terpene pass and cannabinoid pass. (A fourth pass is sometimes performed on distillate to increase purity or on residue as a “second squeeze” to increase yield.)

4. Over periods of days or weeks, distillation vacuum levels seem to gradually become weaker. Why?

The most common cause concerns the Gas Ballast Valve (GBV). Nearly all cannabinoid stills utilize two-stage rotary vane vacuum pumps, which have a GBV, but many operators don’t know much about them. The issue: Some portion of light components, such as solvents, can typically get past the cold trap. They then dissolve into the pump oil, especially in the first distillation pass, and with a large percentage in the feed (>1%), and/or the vacuum level is too strong for conditions. The oil’s total vapor pressure increases as a result, weakening the vacuum. But if the GBV is opened, a small stream of air enters the pump and sweeps out the dissolved solvents, allowing greater vacuum restoration and without having to change the oil. The GBV should be opened after each pass and at the end of every day for at least 30 minutes, then closed again, while the pump is running deadheaded (inlet closed). (Note that if a diffusion or turbo pump is part of the vacuum system, it will not be a substitute for using the GBV properly).

Case Study: Specialty Silicones Manufacturer Optimizes Processing & Product Quality with Pope

Posted on July 23, 2020

Case Study: Specialty Silicones Manufacturer Optimizes Processing & Product Quality with Pope

 

 

AB Specialty Silicones is a US Manufacturer and Worldwide Distributor of specialty silicone chemicals. They are well known for their customer focus along with providing very high-quality products, service and technical expertise in silicone materials. AB’s core brand Andisil®, encompasses a broad product catalog serving many industries including personal care, dental & medical, specialty chemical manufacturing, electronic encapsulation, adhesives & sealants, coatings, mold making, gypsum, mineral & fiber treatment, pulp manufacturing, roof coatings and others. One of several factors in common with the highest quality polymers, including silicones, is having a very low amount of residual volatiles.

 

AB Speciality Silicones Plant in Waukegan, IL

In the early stages of product development, AB Specialty Silicones reached out to Pope Scientific to explore the best methods for producing low volatile silicone pre-polymers and  polymers. Specifically, AB needed to respond to the demand for volatile-free silicone polymers for encapsulation in the LED industry. This particular application brought unique challenges. Silicones can be heat sensitive, leading to degradation including color change, (prohibited for LED applications). Typical batch mode boiling vessel methods for removal of cyclics and monomers were causing such degradation due to the long residence heating time of many hours.

 

Pope Toll Processing & Pilot Facility, Saukville, WI

After Pope spent some time learning about the specifics of the application and its challenges, they collaborated with AB to develop the best method with strategies for optimizing the end product through lab trials and pilot plant process development. By utilizing short-path molecular distillation with Pope’s Wiped-Film Still technology, the potential for final product degradation and discoloration is greatly reduced or eliminated through efficient equipment and design process, high vacuum, and decreasing the heat exposure time to a matter of seconds.

Once the processing techniques were finalized, Pope began production toll processing campaigns of the material in their Saukville, WI facility. Bill Marman, Pope’s Toll Processing Supervisor was essential in aiding AB with process development and support throughout this initial project, as well as with future projects. “The original tolling run produced around 40 drums of the specialty low volatile silicone polymers,” says Mac Penman, AB Specialty Silicones’ General Manager.

Pope 9” Wiped-Film Polymer Devolatilization System

In 2009, with in-depth collaboration, engineering and processing experience, Pope built AB a 9” Wiped-Film Distillation system to run in-house at their Waukegan, IL facility. Pope helped AB commission the system and was there throughout the installation, performing final equipment testing, process startup and training. They were able to duplicate the processing in-house that they previously had to contract out. “There has always been an open dialogue with Pope. From pricing, to engineering and sales, we’ve gotten great support. We have a great relationship,” says Penman. The new equipment provided AB the ability to increase production of specialty chemicals, often times with complex distillation requirements, for their customers.

Processing has been further optimized through enhancements such as additional control instrumentation and degassing componentry. In 2019, AB added a new Pope 12” Wiped-Film Distillation system to their facility. “The new equipment triples our capacity for producing low volatility materials. Production of high solids, low residual materials are important to meet the growing needs for high purity silicones in specialty electronic applications,” AB Specialty Silicones noted. In 2023, AB expanded again with a 20″ 2-stage Pope Wiped-film molecular still.  All of the product lines AB manufactures – vinyl, hydride, phenyl, and fluoro-functional silicones can be processed in the new equipment. Overall, through their partnership with Pope Scientific – including process expertise, toll processing, and equipment, AB has achieved the competitive advantage in producing high value materials and increased production capabilities.

 

 

Download a PDF of the Case Study

The Basics of Molecular Distillation

Posted on July 15, 2020

The Basics of Molecular Distillation

Article written by Brian Beckley for www.marijuanaventure.com

Although distillation often gets lumped in with extraction, it’s actually the step after extraction, a process that refines the raw oil, removes impurities, waxes and other undesirable elements, like chlorophyll. It turns the extract from the viscous material often used for dabs into a clearer, flavorless, high-potency oil for use in cartridges, tinctures and edibles.

The process also decarboxylates the material, changing the THCA found in the plant into what is generally referred to as “active” THC, and raising the percentage of THC or CBD to levels above 90%.

“The color and the quality of the oil is better,” says Chris Barone, chief science officer at Clear Cannabis. “Purity, potency, color, odor — all that stuff — is brought up to a higher level.”

pope scientific wiped film distillation system

An Old Process

Distillation itself is an old process, one used in many industries, but most notably for making alcohol. Traditional short-path distillation, like that of an old moonshine still, uses a boiling flask to heat the material so it evaporates and is caught on a condenser above. The mash is heated in the flask and the alcohol boils off first. It begins to cool when it hits the condenser and then drips into a collection vessel, leaving the water and other substances behind.

“In that case, you’re driving ethanol off,” explains Dean Segal, vice president of sales and marketing for Pope Scientific.

While this style of distillation was used in the early days of the cannabis industry, boiling the materials for hours at a time degrades the very cannabinoids that the process seeks to distill, resulting in less purity and less yield.

“This problem goes way back to the ’30s and ’40s, when people were starting to distill vitamins and pharmaceuticals,” Segal says.

The solution was lowering the pressure in the chamber.

“Molecular distillation, from a chemistry perspective, is a physical process that relies on heating up the liquid or the resin to its boiling point and separating the constituents of that mixture based on boiling point,” Barone says. “Specifically, molecular distillation is doing it at a substantially reduced pressure.”

The idea is to use a high vacuum to help increase the space between molecules so that they can be boiled and separated at a lower temperature than usual, ensuring a better final product.

“This problem goes way back to the ’30s and ’40s, when people were starting to distill vitamins and pharmaceuticals,” Segal says.

The solution was lowering the pressure in the chamber.

“Molecular distillation, from a chemistry perspective, is a physical process that relies on heating up the liquid or the resin to its boiling point and separating the constituents of that mixture based on boiling point,” Barone says. “Specifically, molecular distillation is doing it at a substantially reduced pressure.”


Read the entire article >>

Stainless Steel vs. Borosilicate Glass Wiped-Film Stills

Posted on April 9, 2020

pope stainless steel wiped film still, stainless steel vs. borosilicate glass wiped film stills

Pope Stainless Steel Wiped-Film Still

Stainless Steel vs. Borosilicate Glass Wiped-Film Stills

Pope Scientific manufactures Wiped Film Stills in both 316L stainless steel and borosilicate glass. When selecting a still system for purchase, materials of construction matter just as much as size and other features. Both have their benefits, but how do you know which one is right for you?

pope glass wiped film still, stainless steel vs. borosilicate glass wiped film stills

Pope Glass Wiped-Film Still

Borosilicate glass has been utilized and trusted in laboratories the world over. At Pope, our glass components are annealed to over 1100F and can be relied upon for all your daily processing needs. Every chemist likes to be able to observe what is going on and glass allows looking into the process and making parameter changes as needed. Every chemist also knows that glass can break when mistakes are made.

Pope Scientific 316L stainless steel Wiped-Film Stills don’t break and not only have more robust construction but also allow faster distillation processing. Stainless steel has a greater heat transfer rate than glass, resulting in more than double the processing throughput than its glass Wiped Film Still cousin. We do recommend gaining experience on a greater visibility glass still before switching over to stainless steel where observation is limited to material entering and leaving the still body. We offer stainless steel conversion kits with adapters to the peripheral components as well as turnkey 100% stainless steel systems with sight glasses for full process view.

Isolation with Crystallizing Reactors | Nutsche Filter-Dryers

Posted on March 26, 2020

Isolation with Crystallizing Reactors | Nutsche Filter-Dryers

Pope Nutsche Filter-Dryers are known and used worldwide for final purification of pharmaceutical intermediates, high purity fine chemicals and other critical applications. Pope Reactors and Vessel Systems have been utilized for decades in the same industries. In many cases, Pope supplies reactors utilized for crystallization and a companion Nutsche for filtering, washing and drying the crystal slurries transferred from the reactor.

The advantages of pairing a reactor and Nutsche Filter-Dryer include:

  • Each vessel is optimally designed for performing these two different processes
  • Saves time by having both processes running simultaneously
  • Can be performed with no open handling of the raw material or slurry

Isolation is a critical operation, and often the final step in the entire manufacturing process. Pope Scientific’s Nutsches are preferred-proven for CBD crystalizing isolation to 99.9%, with less than 0.3%, to undetectable THC levels.

 

isolation crystallizing reactors and nutsche filter dryers

TURNKEY SYSTEMS

Pope offers a turnkey 5L reactor and 4L Nutsche that can be used for benchtop development work and small-scale production.

Pope has developed a variety of turnkey systems for creating CBD isolate, including:

  • 5L Reactor and 4L Nutsche (Benchtop scale)
  • 30L Reactor and 25L Nutsche
  • 60L Reactor and 50L Nutsche
  • 120L Reactor and 100L Nutsche
  • 200L Reactor and 170L Nutsche
  • 400L Reactor and 350L Nutsche
  • Custom sizes and designs available upon request

PROCESS VESSELS

  • Pressure Vessels from 0.1to 5000 Liters
  • High Purity, Sanitary, Pharmaceutical Designs & Finishes Available
  • Special Designs for Reactors, Fermenters, Mixers, Homogenizers, Dispensers, Hydrogenators & Other Turnkey Systems

NUTSCHE FILTERS

  • Benchtop Models are the Logical Step Up from Laboratory Buchner Funnels
  • All-in-One Solution for Filtering, Washing, Reslurrying, Mixing & Drying High Purity Solids
  • Lab, Pilot & Production Scale

Have questions? Contact us about your application today!

Ask the Experts: 5 Questions on Wiped Film Distillation

Posted on March 5, 2020

Ask the Experts: 5 Questions on Wiped Film Distillation


Wiped film distillation is often carried out using strict set of methods and parameters from internal Standard Operating Procedures, but incoming extract material composition is not fixed; it changes depending on various factors, so do product goals. Dean Segal, vice president of sales and marketing for Pope Scientific, shares distillation approaches and strategies for adapting to such changes for optimization of product quality, yield and profit.

  1. Do Wiped Film Molecular Stills Operate Similarly to Boiling Flask “Short Path” Stills?

No, boiling flask stills are batch-mode apparatuses where compositions change incrementally the entire run. Wiped film molecular distillation is a continuous mode operation, thus the feed, distillate and residue compositions remain constant for the entire run. Feed material, kept flowing at a fixed feed rate, enters a high vacuum heated boiling zone for a short residence time, where some portion of it is evaporated away and condensed. Thus, the feed is split into two streams, distillate and residue, both being collected and/or pumped away. Three principal operating parameters— feed rate, temperature and vacuum level— determine how much is collected as distillate and how much is collected as residue, sometimes referred to as the “split” or “Mass Balance” (MB).

  1. Should Molecular Stills be Run the Same Way Each Time?

Incoming feed material changes in quality and composition, plus product goals can change as well. Thus, for optimal results, it’s better to modify parameters rather than keep them fixed for every run. A rule of thumb is to shoot for splitting the feed into something close to the total cannabinoid percentage. For example, if a new extract lot comes in at 60-percent total cannabinoid, aim for a MB of roughly 60:40, not 85:15.

 

three stage six inch cannabinoid distillation machine

Pope Turnkey, 3-Stage, PLC Controlled, Pharmaceutical-grade, Cannabinoid Distillation System

 

  1. How is Distillation Optimized to Accommodate Product Goals?

One approach, (A), is quality over yield; the other, (B), is yield over quality. In approach A, one may adjust the temperature to a MB to correspond to a bit under the percent of cannabinoid, resulting in a clear yellow distillate of good quality. There may be a nominal amount of cannabinoid remaining in the residue that can be combined later with other residues from similar runs, and later, this material can be re-distilled to recover a “second squeeze” of cannabinoid for less critical product use. In approach B, a “deeper” cut is made, with MB somewhat greater than the percent cannabinoid to ensure most of the available cannabinoid is removed. If the goal includes having at least some premium-grade product, the distillate, instead of residue, may be re-distilled to obtain product upwards of 90% cannabinoid, and the residue, depending on its analysis, may be utilized in a secondary product line, particularly when clarity and lightness is not essential, e.g., chocolate edibles.

  1. Can Different Strategies be Incorporated into the Design of a Production System?

Yes, this is accomplished by having more than two stages in the system. If there are three stages, the third can be used either for re-distilling the residue (increasing yield) or else re-distilling the distillate (increasing purity). Alternatively, the first stage could be used for stripping out excessive (>3%) solvents, the second for collection of any remaining solvent and heavier terpenes, and the third for cannabinoid distillation. Having four stages makes it possible to run two, two-stage distillations in parallel, doubling the throughput of the still system. Great flexibility is possible with such multistage systems.

  1. Are Terpenes Lost in a Molecular Distillation System?

Often, most terpenes are lost prior to the distillation step. If they are still present and in usable condition, they can be captured for reuse such as adding back to final distillate product via incorporation of an external condenser—a component, which is one of the features of Pope Cannabis Distillation stills.

Originally published in Cannabis Business Times

Pope’s History and Bright Future

Posted on November 20, 2019

Pope’s History and Bright Future

 

For more than half a century, Pope Scientific Inc. has been at the forefront of manufacturing chemical processing equipment, engineered systems and laboratory apparatus for science and industry. Founded in 1963, The company quickly started doing business worldwide in a broad variety of industries with expanded offerings of production processing equipment including the Wiped-Film Molecular Distillation line and Toll Processing Services. Our first cannabinoid customer application goes back to 2003 for post-extraction CBD purification via Pope 2″ wiped film stills.  The hemp came from dumpsters, actually being tossed out as waste byproduct from hemp seed oil processing. How times have changed! Today, Pope sits at the forefront of cannabis processing technology with distillation, extraction, and isolation equipment being provided in the USA and internationally.

Pope Breaking Ground

Pope breaking ground on the new expansion. Left to right: Geoff Martin, Thomas Martin, Rich DeLuca and Dean Segal of Pope.

Pope Glassblowers

Glass blowers at work at Pope’s manufacturing facility in WI, USA in the late 1970s.

Our long history demonstrates how clients have brought both routine and difficult and demanding separation/purification/mixing applications to us to make their solutions a reality…why we are solution driven.

In 1998, Pope moved into a 44,000 square foot manufacturing facility in Saukville, just north of Milwaukee, Wisconsin.  The new facility supported our engineering, construction areas, technical and testing labs, glassblowing facility, shipping /storage and a fully equipped toll processing area.

Today, to support Pope’s growing business we are expanding yet again.  Pope recently broke ground on 20,000 square foot building expansion to our Saukville office. We are thrilled to be manufacturing proudly in the US.  The nearly 50% increase in space will be multi-use and include more state of the art manufacturing space as well as offices. Our expansion is estimated to be complete in May 2020.  We’d like to thank all our customers, new and old, for their support over the years and we look forward to a bright future.  Stay tuned to see progress as we get closer to completion!

Pope On Stage at CannaTech Tel Aviv 2019

Posted on November 19, 2019

Pope On Stage at CannaTech Tel Aviv 2019

Pope Cannabis Presentation - Dean Segal

“Distillation of Cannabis Extracts” was the seminar topic as Pope Scientific expert detailed the chemical processing behind obtaining high purity cannabinoids and recovering terpenes

Dean Segal, Vice President of Sales & Marketing who holds B.S. degrees in both Chemical Engineering and Biochemistry, was on the agenda at CannaTech Tel Aviv—a next-level medical cannabis conference bringing together industry influencers and thought leaders to discover, connect and accelerate medical cannabis innovation.

Part of Segal’s presentation highlighted the reasons to distill crude extract, which included:

  • Increased purity of cannabinoids [Typical example being 65% in trim going to 85-90%]
  • Removal of heavies, chlorophyll, larger waxes, salts, sugars, higher MW pesticides, etc.
  • Product becomes clear light yellow, from dark opaque brown
  • If product is to be used as vape, better to leave out heavies and solids
  • If product is to be isolated [chromatography, crystallization, etc.], results in greater purity and much greater yield
  • Improvements are gained without introduction of solvents, etc.

Segal also worked the trade show floor representing Pope Scientific at the Rhenium booth. A sponsor of the event, Rhenium is one of Israel’s leading suppliers of laboratory, research and diagnostic equipment; working with top-level manufacturers from around the world like Pope to import solution-driven  equipment.

Ask the Experts on Distillation: 5 Questions with Dean Segal

Posted on November 19, 2019

Ask the Experts on Distillation: 5 Questions with Dean Segal

For further refinement of your extracted cannabis material, it’s important to understand the options available on the market, as well as how to make your distillation process as efficient and seamless as possible. Here, Dean Segal of Pope Scientific shares some things you need to know about wiped film stills, how to improve wiped film still operation results and more.

1. What are some advantages of a wiped film still (WFS)?
A WFS is a high-efficiency molecular short path distillation system utilizing high vacuum, dynamic wall wiping, brief heating and a condensing surface a short distance from the evaporation surface. This, plus the continuous mode operation of the WFS cuts the heating residence time to seconds, versus hours. That’s important, because the longer the material boils, the more it will degrade—resulting in lower purity, yield, clarity and ultimately, profit. WFS will perform the same in larger size and throughput versions, as it will enlarge proportionally, leaving ample room for proper evaporation. “Short path” units, because they are spherical in make-up, do not have this scalability advantage. In fact, when they are made larger, the ratio of volume to available evaporation area (boundary where liquid interfaces with vapor) declines substantially, and relative throughput decreases.

2. Will wiped film molecular distillation work well after different types of extraction and other process steps?
Yes. You can count on improved purity and clarity whether hydrocarbon, ethanol, supercritical or other extraction methods were utilized. Winterizing (removing wax) is not required, but without it, you’ll need to clean and maintain the still more often. The still will also work well whether or not decarboxylation has been performed.

Pope Turnkey WFS System For 50 Kg/Hr

Pope Turnkey WFS System For 50 Kg/Hr

3. Should a wiped film still be procured large enough for estimated production rates a year or two down the road?
No, there are operational problems that arise when the equipment is much larger than needed for the near term. Start with a still matching actual production rate needs for the first six months, then revisit multiple unit needs later after operation has been running steadily. And because the WFS is scalable, when much greater quantities of material need to be processed, larger versions of equipment can be successfully utilized.

4. What is the most common problem typically encountered in operating wiped film stills?
By far, the most frequent issues we see have to do with insufficient prior removal of light components such as ethanol, water, lighter terpenes, gases, etc. These should have been decreased to lower values earlier via more aggressive rotovaping, decarboxylating and feed flask degassing. This allows greater vacuum, less flashing, better color, throughput, purity and yield. An early indication of a problem is when the first pass is running at more than a few torr and/or more than 1 percent of feed collecting in the cold trap.

5. What things are helpful to improve wiped film still operation results?
Proper maintenance of vacuum pumps and leak checking is more important than massive capacity rotary vane and booster pumps. If better than 0.02-torr in a clean, dry still is not obtainable, check for leaks and pump health and learn how to use your gas ballast valve! Know the inter-relationship of feed rate, vacuum level and temperature. Strategize your operation based on extract composition and product goals, and tweak parameters to optimize each run. Adapt for variations in starting material.

Originally published in Cannabis Business Times | Ask the experts: Distillation

Benchtop Nutsche Filter-Dryer Systems

Posted on October 2, 2018

Benchtop Nutsche Filter-Dryer Systems

 

Pope 3-liter Benchtop Nutsche Filter with optional motorized raising/lowering filter cake agitator.

Solids, crystals, high purity chemicals, pharmaceutical intermediates, etc., are efficiently filtered, washed, reslurried and dried in these portable nutsche filter-dryer systems, minimizing contamination and exposure. A logical leap forward from laboratory Buchner funnels. Design allows withdrawal of filter cake utilizing removable top head, bottom head and filter support assembly. May be pressurized to increase rate of solvent removal; drying is aided by vacuum and heating capability. Useful for experimentation and scale up studies; also for small scale production of high value products.

Standard models in 3, 4 or 5-liter sizes are stocked for quick delivery. Other lab sizes down to 0.2 liters and pilot/production sizes up to 1000 liters are offered. ASME and optional CE/PED certification for full vacuum to 100 psi, -80 to 250o C. Offered in stainless steel, Hastelloy, or alternate metals; optional food or pharmaceutical grade mechanical and electropolish finishes; Teflon or alternate coatings. Custom design features include manual or motorized raising/lowering cake agitators, mixers, temperature control options, jacketing, valving, special porting, sight glasses, instrumentation, pumps, etc., plus a wide range of easily replaceable filter media.