Technical & Practical
Reduce Hazards in Process Vacuum Systems
Vacuum conditions for many unit operations — including distillation, evaporation, drying, crystallization, filtration and more — are typically achieved using the following three approaches: • Steam ejector systems • Mechanical vacuum pumps • Integrated vacuum systems (which combine steam ejectors…
Fans and Blowers
Fans and blowers are common in air-handling and movement systems used in the chemical process industries (CPI). Two major uses of fans and blowers are in pneumatic conveying systems and in ventilation and air-pollution-control systems. Powering fans and blowers can…
Gas Sparging
Sparging refers to the process of injecting a gas through a diffuser into a liquid phase. It is used in both physical and chemical process applications. In physical process applications, the gas is used to either dissolve gas into liquid…
Thin-Film Drying Offers Deep Benefits
Thin-film drying is a continuous drying technology that is safe, flexible and offers many benefits, including low operating costs, low space requirements and high specific-evaporation capacity Contact agitated dryers are used for drying wet powders, slurries, filter cakes, and applications…
Condition Monitoring Methods for Pumps
Pumps are among the most commonly used machines in the chemical process industries (CPI). Condition monitoring tests and predictive maintenance can help pump operators determine when to overhaul pumps in a way that minimizes costs. Despite pumps’ ubiquity and large…
Cooling Water Outlet Temperature: Evaluating The Best Maximum Value
Corrections: From the October 2012 Letters page: This original article, which appeared in the print edition of Chemical Engineering (September 2012), had two errors: Equation (19) should read D = log (TH)-0.4, and Table 2 was missing decimal points in…
Vacuum Systems: Recommendations For Safe Operation
This article is the first in a two-part series, in which the types of process vacuum equipment (steam ejector systems and mechanical vacuum pumps) are discussed.1 Emphasis is given on how they are constructed and operate, and how to design…
Reciprocating Compressors: Startup and Capacity Control Methods
There are two main reasons why compressor capacity regulation is used. The most prevalent reason is to adjust the suction flow to match the process demand. The second reason is to save energy. As a rule, capacity control is determined…
Heat-transfer expansion tank design
The main function of the expansion tank in a heat-transfer system is to allow space for the heat-transfer fluid to expand as it is heated. A properly designed, installed and maintained expansion tank will support longer fluid and equipment life,…
Waterhammer In Condensate Return Lines
There is a temptation that steam design engineers find difficult to resist — to put condensate from high-pressure (HP) steam mains directly into the low-pressure (LP), pumped condensate-return (CR) mains. After all, the CR main is so convenient — it…