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Volume 09 Issue 01
  Volume 10 Issue 2 BHS-Sonthofen Inc. July 16, 2019  
     Focus | Featured Article | Technology Application | Innovations | Upcoming Events | Blog 

Focus:  Using Filter Aids

Welcome to Year Number 10 of A&SoF.

It’s exciting to look back and reread all of the past issues and realize that the insights and examples remain relevant to our industries today.  2019 will be a year of growth for BHS including the acquisition of AVA , innovative process engineering solutions as well as an expanded team to support our customers.  This will lead to marketplace changes and follows directly from the theme of my blog for this month “Becoming Uncomfortable in 2019.  It is going to be fun.

 This issue focuses on the using filter aids.  We will discuss the types of filter aids, how to use them, filter technologies and trouble shooting. 

As always, thanks again, to our readers, for your feedback and if you missed any issues, please click on the following link:  A&SoF to view them.  Have an enjoyable and safe 2019. 

Barry A. Perlmutter

Featured Article:  Using Filter Aids

Make the Most of Filter Aids:

Understand the types of these materials and their appropriate applications

Chemical Processing, May 2019 issue, pages 7 – 9, 2018

Many chemical processes require removal of fine solid contaminants smaller than 5 µm from liquids. When the suspended solids content is dilute, typically less than 1% by weight, the operation to produce a clean liquid product is called clarification or polishing filtration. Typical applications include catalyst recovery, polymer and resins, active pharmaceutical ingredients, removal of unreacted chemicals and byproducts, and polishing of gray water.
Often in polishing applications, the solids are very fine or amorphous, making them difficult to filter. When filtered, the solids will create a thin impermeable coating over the filter medium and immediately reduce the filtration rate to an unacceptable level. In these difficult cases, filter aid pretreatment may improve filtration properties and efficiently remove the fine solids.

Filter aids can serve in the filtration cycles of various types of filters:
• Plate-and-frame filter presses;
• Horizontal and vertical pressure leaf filters;
• Candle or tubular filters;
• Nutsche filters; and
• Rotary vacuum drum filters.

Read the full article…

BHS Technology Application:

Ditch the Bag Filters 

Barry A. Perlmutter, BHS-Sonthofen Inc.
The Chemical Engineer, May 2019, Issue 935

Over my career in the solid-liquid separation market space, I have seen interesting examples of how to solve a solid-liquid separation problem.  In one case, I was at a melamine resin facility where the slurry was in a formaldehyde process and the operators were in a room 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.  There are many examples of process engineers struggling to clarify process liquids.  What are some possibilities to automate the clarification processes to improve filtration while minimizing operator exposure?
Read more…


BHS Case History:

Pharma Product Recovery Using BHS Candle Filters
Downstream of Centrifuges

In the present process, the pharma slurry goes to a centrifuge for separation and washing and the cake is discharged as the product.  The centrate of the centrifuge is a waste material.  However, the centrate contains soluble product which is presently lost. The purpose of this project is to recover this material.
The proposed system is to precipitate the material from the centrate and then concentrate the material using BHS candle filters and return the concentrated product back to the process. 
After extensive testing, the BHS candle filter was installed.  The unit is producing concentrated slurry of 10% from an initial concentration of 1.2%.  The design of the BHS candle filter followed cGMP guidelines including the qualification documents. 
For more information on the BHS candle filter technology, please visit our website at:


Chemical Engineers & Our Superstitions

Superstitions surround us: Touching wood? Carrying a rabbit’s foot? Collecting lucky pennies? Not stepping on any cracks? The list goes on and on.   I have read an interesting article on superstitions and six luminaries from different walks of life — photography, acting, cooking, writing, directing and music — weighed in. But, alas, there were no chemical engineers.  However, the one overriding theme, as photographer Gregory Crewdson stated, is that a belief in superstition “comes down to order” and wanting “to clear your path of unknowns.”  This is what we do as chemical engineers.

Read the blog

Upcoming Events:

  1.  Specialty & Custom Chemicals America:  Fort Worth, Texas, 11 -14 February 2019,
  2.  AICHE Spring Meeting: New  Orleans, 31 March – 4 April 2019,
  3.  Global Petroleum Show:  Calgary, Alberta, Canada, 11 – 13 June 2019, 
  4. The Chem Show:  New York City,  22  - 24 October 2019
Copyright © 2019 BHS-Sonthofen, Inc., All rights reserved.
BHS-Sonthofen, Inc.
14300 South Lakes Drive
Charlotte, NC 28273-8794
Phone:  704-845-1190

BHS specializes in thin-cake filtration, washing, and drying technologies for pressure or vacuum, batch or continuous operation for high solids and clarification applications.

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