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Cellulose nanomaterials are produced employing a multitude of methodologies including electrospinning, bacterial generation, acid digestion, and a variety of mechanical defibrillation techniques; the morphology of the nanomaterial produced is specific to the production process. Feedstocks range from various forms of woody biomass, to fungi, and have a great impact on the resulting product. The mechanical defibrillation technique, such as that employed in the present work, continuously breaks down cellulose fibers suspended in water via segmentation and defibrillation through grinding and refining. The process is typically operated until a desired level of fines is achieved in the resultant slurry of cellulose nanofiber (CNF), alternatively known as cellulose nanofibril. Mechanical defibrillation processes can be built to produce several liters in a small batch system or up to tons per day in a continuous pilot scale refiner system. In the present work a continuous system was developed with the capacity to produce 14 L of cellulose nanofiber slurry with consistent specifications and in a manner compliant with GMP/GLP protocols in order to be amenable to biomedical applications. The system was constructed within an ISO class 7 cleanroom and refining was performed on bleached softwood pulp suspension in purified water. This manuscript details the continuous grinding system, the processes employed to produce cellulose nanofiber, and characterizes the resultant cellulose nanofiber slurry and sheets formed from the slurry.
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Residence Time Distribution Characterization and Proof-of-Concept of a Novel Stacked 7-Stage Continuous Crystallizer Cascade with Diaphragm-Driven Slurry Transfer
Process developers in the pharmaceutical industry lack readily deployable, standardized, off-the-shelf continuous crystallizers (<100 mL), abiding the low material requirements of early stage product development. This study evaluates a novel continuous tower crystallizer (TWC), hosting a series of seven vertically stacked mixed suspension mixed product removal crystallizers (MSMPRCs, 80 mL total volume) enabled by an innovative diaphragm driven slurry transfer, which eliminates known transfer line issues in MSMPRC cascades. Residence time distribution measurements using the model compound glycine demonstrate ideal mixing for both liquid (homogeneous) and solid (heterogeneous) phases (particle < 100 μm, slurry density < 22.8%). A comparison with the tank in series model reveals nonideal mixing for particles >300 μm. Finally, a proof-of-concept continuous antisolvent crystallization of glycine demonstrates the TWC’s capability to produce high-quality crystals continuously, proving its functional and robust operation
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- PAR ID:
- 10565782
- Editor(s):
- Michael_Baldea
- Publisher / Repository:
- ACS
- Date Published:
- Journal Name:
- Industrial & Engineering Chemistry Research
- Edition / Version:
- -
- Volume:
- 63
- Issue:
- 42
- ISSN:
- 0888-5885
- Page Range / eLocation ID:
- 18199 to 18211
- Subject(s) / Keyword(s):
- Crystallization Crystals Liquids Materials Particle size
- Format(s):
- Medium: X Size: - Other: PDF
- Size(s):
- -
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acs.iecr.4c02153
