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engineering how-to
Selecting a Positive Displacement Pump
By John Petersen and Rodger Jacoby, Viking Pump Inc.

The need to reduce production costs and optimize energy consumption makes proper pump selection more important than ever. Understanding basic pumping principles and the fluid characteristics for a given application is the starting point for selection.  It has been said that pumps are the second most common piece of industrial equipment next to electric motors. There are literally millions of pumps in use around the world handling thousands of different liquids. With the many types of pumps available, selecting the proper pump for any given application can be complex. The pump selection process is, in large part, matching a particular pump’s capability with system requirements and properties of the liquid to be pumped. This article begins with a discussion of liquid and system properties and then moves on to examining specific pump capabilities. The first consideration in any application is understanding the expectations for the pump. Inlet conditions, required flowrate, differential pressure, temperature, and liquid characteristics — such as viscosity, abrasiveness, shear sensitivity and corrosiveness — must all be determined before a pump can be selected. »
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Addressing Pumping Issues in Biopharmaceutical Operations
By Glenn Hiroyasu and Sueli Roel Backes, Almatec

Biopharmaceutical, pharmaceutical and nutraceutical manufacturing may come in a wide variety of forms, but every iteration of unit operation must adhere to an unbending set of operational parameters and structures if the desired outcome — a viable, contaminant-free drug suitable for human or animal administration — is to be realized. It is all about “controlled fluid transfer.” Three of the more common unit operations within the biopharmaceutical-manufacturing universe are chromatography, virus filtration and tangential flow filtration (TFF). In order for these unique operations to be implemented successfully, though, the operator must be aware of their specific operating characteristics. For example, chromatography requires constant fluid flowrates during their operations, but may have varying pumping pressures. Virus filtration, on the other hand, will feature constant pumping pressures, but flowrates will change as the filters become clogged or fouled. And in TFF, the main challenge is attempting to keep the flowrate and pressure unchanging throughout the process. »

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Facts at Your Fingertips
Variable Frequency Drives
Electric alternating current (a.c.) motors power all types of equipment in the chemical process industries (CPI), including pumps, fans, blowers, compressors and other types of process equipment. Electric motor systems offer opportunities for reductions in power consumption because while some applications require a constant motor speed, half of all electric-motor applications have a speed demand that varies with different conditions.
Technology profile
Figure 1. The diagram shows a benzene production process from pyrolysis gasoline 

Benzene Production from Pyrolysis Gas

Benzene is the simplest and most important industrial aromatic hydrocarbon. It is a versatile petrochemical building block, and is an intermediate for several industrially important commodity chemicals and polymers, such as ethylbenzene, cumene, cyclohexane and others. Benzene is used in the production of pharmaceuticals, specialty chemicals, plastics, resins, dyes and pesticides. This month's Technology Profile describes a process for benzene production from pyrolysis gasoline.
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Improving Operabilty & Reliability Volume 1: Equipment Systems
This book provides a wealth of information, engineering recommendations and strategies for keeping plant components running in top condition, and taking the necessary steps to avert problems that can lead to unwanted downtime, increased maintenance costs and safety or environmental problems. Articles included focus on such key topics as proper design, operation and management of pumps, valves, fans, heat exchangers, boilers, compressors and more.  Also provided is guidance for proper temperature measurement and control, piping system design and maintenance, bulk-solids handling tips. 
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