A virtually endless number of process options are available for agglomerating powders in the chemical process industries (CPI). These processes can be divided into two main categories: agitation and compression. Agglomeration by agitation includes granulation processes, such as fluidized-bed, disc, drum and mixer granulators. Agglomeration by compression includes compaction processes, such as tabletting, extrusion, roll presses and pellet mills. Process choice is affected by certain feed attributes as well as a host of ancillary decisions. This article focuses on equipment selection criteria for granulation and compaction processes. The mechanisms of agglomeration were reviewed in an earlier article [ 1 ],... http://www.che.com/processing_and_handling/solids_handling/Agglomeration-Technology-Equipment-Selection_5641.html
Question: What can we do to prevent caking? When our powders are packaged into bags at our plant, they appear to be free of agglomerates. However, our customers report that when the bags are opened at their facilities, they observe an excessive amount of caked material. This results in rework and potential losses in sales. We suspect that moisture is the cause, but our bags include a vapor barrier, and our records show that we are indeed producing dry materials.... http://www.che.com/processing_and_handling/solids_handling/Ask-the-Experts-Cake-Prevention_5600.html
A rapid and ongoing expansion of polysilicon production capacity will likely generate an oversupply for the next several years, driving polysilicon manufacturers to further innovate processes and reduce operating costs in preparation for an impending wave of new demand.... http://www.che.com/processing_and_handling/solids_handling/Polysilicon-Production_5559.html
Particulate systems are everywhere; they are responsible for bright red sunsets, the texture of chocolate and the rate of drug delivery in the human body. Particulate processing and size control originated back in prehistoric times where mixtures of pigments were finely pulverized and used in the painting of cavern walls. From those primitive beginnings, the use and processing of particulate matter has grown to be of paramount importance in virtually all modern industries. In an attempt to meet the challenge of these remarkably wide particle characterization requirements, from nanosize to millimeters, a considerable number of technologies have been developed over the years to measure the size of particles.... http://www.che.com/processing_and_handling/solids_handling/testing_and_modeling/Particle-Sizing-Across-the-CPI_5574.html
Powder agglomeration is used in a wide variety of the chemical process industries (CPI), and a virtually endless number of process options are available. Selection requires engineers to make a substantial number of design decisions, such as the choice between wet or dry processing, the intensity of mixing and shear rates, continuous versus batch operation, cross contamination of products and ease of cleaning. These choices must be made in light of desirable agglomerate end-use properties. Key agglomeration mechanisms and their impact on agglomeration processing are reviewed in this article. The impact on process selection is also touched upon within the context of mechanisms.... http://www.che.com/processing_and_handling/solids_handling/Agglomeration-Technology-Mechanisms_5497.html
Many branches of the chemical process industries (CPI) make use of impact comminution to process solid matter, such as minerals, foodstuffs, pharmaceutical products, and above all, products for the chemicals industry. Impact comminution is also used for coarse crushing, but the focus of this article is fine grinding with end-product particle sizes below 500 µm. The technology of impact comminution is, however, not particularly popular with the users of impact grinding systems because it is energy-intensive, associated with a high noise level and frequently also gives rise to time-consuming maintenance work. In spite of this, impact comminution is still the most cost-effective solution in many processing operations.... http://www.che.com/processing_and_handling/solids_handling/milling_grinding_and_screening/Fine-Grinding-With-Impact-Mills_4989.html
Evaporation of moisture or volatile organic compounds (VOCs) from bulk solids usually takes place in two stages: one in which the drying rate is constant, and the second in which the rate decreases over time. Devolatilization during the first stage is rapid and can be readily accomplished in flash, spray, or fluidized bed dryers. In the second stage, however, the VOC or moisture removal rate is diffusion limited, and several hours of residence time are often necessary. To meet low moisture or VOC targets, two unit operations may be required. An economical way to provide the extended residence time required for slow, diffusion-limited drying is to use a bin or silo that has been modified to allow injection of a sweeping gas and, in some cases, to provide heating. These unit operations, which have a variety of names including gravity dryers, offer numerous advantages.
Among all the components of a pneumatic conveying system, bends — despite their apparent simplicity — are probably the least understood and most potentially problematic for process operators. Findings from various research studies are often not consistent, and often times public findings do not match field experience. The importance of bends in any pneumatic conveying assembly cannot be overstated since — if not properly selected and designed — they can contribute significantly to overall pressure drop, product attrition (degradation) and system maintenance (due to erosive wear). This article summarizes the key concepts, outline key metrics used to evaluate bend performance, and provide guidance for their selection. The discussion is limited to dilute-phase conveying.... http://www.che.com/processing_and_handling/solids_handling/feeding_and_conveying/Understanding-Bends-In-Pneumatic-Conveying-Systems_4655.html
The patented design of this unit improves grinder efficiency; When spark reduction is important, use these grinding discs; Achieve small media milling with this production mill; Get tight control of a process with realtime remote mill operation; and more
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