Technical & Practical
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…
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…
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…
Control Valves: An Evolution In Design
Globe-style control valves are in virtually every chemical processing line where pressure and flow must be controlled. And for the most part, they perform as required, day in and day out, requiring little to no thought or attention. In short,…
A Primer on Gas-Solid Fluidization
The earliest application of the fundamental concepts of fluidization dates back to 16th century when a German scientist (Georgius Agricola) described a process to upgrade ores. However, it was not until the 1930s, with the development of the Winkler coal-gasification…
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,…
Internal Corrosion Sampling
Corrosion is a large and complex issue that is critical to the chemical process industries (CPI) as well as other industry sectors. Corrosion not only affects personal property like cars and homes but also affects commercial assets such as storage…