Displaying 1–25 of 30 results for Tom Blackwood, contributing editor
Chemical Processing gains a new columnist to give readers some “Solid Advice” on handling solids, and welcomes two new members to its Editorial Board.
Schools largely ignore solids processing but many plants handle solids. So, it’s important to know that particulates often exist in more than one form or crystal structure. This can lead to clumping and other issues.
Crystallization seems easy — cool a solution and product drops out. Unfortunately, various issues can afflict the process, including not getting the right size particles or getting particles that take too long to dry. Here are some tips for avoiding problems.
Particle fluidization often can offer important benefits such as improved heat transfer and possibly better mixing. Even when attrition or product segregation poses risks, limitations can be designed around or even used to advantage. Here’re some tips.
Blenders often don’t perform properly because users have accepted certain myths — e.g., ones related to blending time, equipment comparability and fluidization. This column debunks those myths and provides some pointers for successful blending.
Plants that must dry solids sometimes run into problems that can be solved most effectively by challenging what they are doing and the equipment they are using. Here are some examples of the value of taking a fresh look at drying operations.
Sampling is crucial and demands particular care because fine particles tend to not follow the path of other particles and are more susceptible to segregation. Two problems that arose — with a thief sampler and with a blender — provide important insights.
To deal better with wet cakes, pastes and slurries, a plant should consider the possibility of altering bulk properties. Options include pre-forming of pastes, size enlargement of wet solids, shear-strength reduction, and partial drying of a cake surface.
Plants often offer telltale signs of flow problems, such as a hammer or barrels near equipment or welded-on patches. Flowability testing is expensive and, so, frequently neglected during process development but can head off potential issues.
Chemists developing a process don’t have the same concerns as engineers trying to scale it up. However, a chemist can identify the physical properties and extrinsic conditions that control various steps and ease coming up with a meaningful design.
One often-overlooked consideration in dryer selection is prevention of solvent (or moisture) from re-binding to the product. Understanding how the solvent is held in the particulate solid is important. Eight test methods can provide key insights.
Use a vendor’s facility to get information on a number of important parameters
Solids processing is complex. Unfortunately, spending countless hours on research often won’t lead to finding the necessary insights for design or equipment selection. In many cases, the proper solution relies more on art than basic science.
When wet, almost all fine solids are sticky. In addition, many particles will clump together. This often leads to plugging of fluidized-bed dryers. Attention to three factors is crucial for successful handling of particulate solids in a fluidized bed.
Determine what type of blender you need – mechanical, gravity or fluid-assisted – and understand the pros and cons of each.
When faced with a drying problem, use drying curves to take a closer look.
Handling wet solids present several challenges, particularly when it comes to storage.
Operations involving crystallization often suffer problems that easily could be avoided through insights available from a solubility curve. This column highlights eight crucial factors for ensuring the curve properly represents the product and operation.
everal approaches exist to help resolve the issue of solids settling in slurries.
Sometimes, engineers are surprised when well-known scientific principles explain the actions of particulate solids.
A variety of techniques can provide data on the most stable form of a chemical to be recovered by crystallization. If an unstable form is desired, these data will allow tailoring the process to avoid the stable product.
Fine particles often pose problems, but several options exist to help minimize issues and customer complaints.
A plant should assess several critical factors such as how material will be unloaded or loaded, how sensitive a material is to attrition, agglomeration, vibration and mechanical deformation, and what will be done with used bags.
Often, because of cost or lack of understanding of its importance, instrumentation gets left out of solids processes, causing ongoing problems. Four measurements usually are necessary to adequately control systems.
Selecting the best separation method to use for a new product going from the laboratory to small scale production can be difficult. Several tests can provide crucial insights on whether to choose a filter or a centrifuge.