Bench-top operations

Applied general chemistry and physics are two fundamental courses that have been recommended by industry for inclusion in process technology programs. It is clear that information contained in academic chemistry and physics courses does not address key topics required by the occupation. Also, the process safety management standard requires that process technicians have an understanding of the chemistry and physics associated with the processes they are operating. Figure 2-11 demonstrates how adult learners can use hands-on bench-top operations to understand the science associated with difficult topics. 

Process technology programs include traditional coursework and hands-on training. Theory courses cover safety, quality, process equipment, physics, chemistry, and instrumentation. The hands-on component emphasizes process systems, troubleshooting, and operations. These classes include console training, bench-top operations, and pilot plant operations. 

The objective of experimental design in bench-top operations is to determine which variables in the process or product are the critical parameters and their setpoint values. By using formal experimental techniques, the effect of many variables can be studied at one time. 

Define the term bench-top operations and describe the purposes of a bench-top unit. 

In 2009 I graduated from technical college with an Associate of Applied Science (AAS) degree in Process Technology. My course of studies included the operation and maintenance of a full-scale pilot plant, console operation, bench-top operation, process equipment and systems instrumentation, chemistry, math, and physics. Additional topics of study included safety, quality control, troubleshooting, and the academic core. 

During some operations, the vapor appears to pulse upward one to three trays at a time. It is also possible to see one or two dry trays in the column while the other sections have a good liquid level above the tray. If the column is being pushed too hard, the upper trays may flood and cause problems In the lower section of the column. It is also possible to see the transfer of heat energy in the condenser as fluid passes in opposite directions. In a glass distillation bench-top operation, it is easy to observe occurrences and record data that are not visible on a large-scale operation. 

Bench-top or microunits will continue to be the predominant type of pdot plant constmcted due to their lower constmction and operating costs. Demonstration and prototype units will become even rarer for the opposite reasons. 

Specificity is unsurpassed. Traditionally, MS was performed on very large and expensive high-resolution sector instruments operated by experienced specialists. The introduction of low-resolution (1 amu), low-cost, bench-top mass spectrometers in the early 1980s provided analysts with a robust analytical tool with a more universal range of application. Two types of bench-top mass spectrometers have predominated the quadrupole or mass-selective detector (MSD) and the ion-trap detector (ITD). These instruments do not have to be operated by specialists and can be utilized routinely by residue analysts after limited training. The MSD is normally operated in the SIM mode to increase detection sensitivity, whereas the ITD is more suited to operate in the full-scan mode, as little or no increase in sensitivity is gained by using SIM. Both MSDs and ITDs are widely used in many laboratories for pesticide residue analyses, and the preferred choice of instrument can only be made after assessment of the performance for a particular application. 

In the past decade, as systems have become simpler to operate, mass spectrometry (MS) has become increasingly popular as a detector for GC. Of all detectors for GC, mass spectrometry, often termed mass selective detector (MSD) in bench-top systems, offers the most versatile combination of sensitivity and selectivity. The fundamentals of MS are discussed elsewhere in this text. Quadrupole (and ion trap, which is a variant of quadrupole) mass analyzers, with electron impact ionization are by far (over 95%) the most commonly used with GC. They offer the benefits of simplicity, small size, rapid scanning of the entire mass range and sensitivity that make an ideal detector for GC. 

This non-destructive technique is a very suitable tool for rapid in-line analysis of inorganic additives in food products (Price and Major, 1990 Anon, 1995). It can be readily used by non-skilled operators, and dry materials can be pressed into a pellet or simply poured into a sample cup. The principles of this technique related to food analysis are described by Pomeranz and Meloan (1994). A useful Internet site is http //www.xraysite.com, which includes information about different XRF instruments from various companies. Wavelength dispersive X-ray fluorescence (WD-XRF) or bench-top energy dispersive (ED-XRF) instruments are available. XRF is a comparative technique, thus a calibration curve needs to be established using food products of the same type as those to be... 

Experimental work to date confirms that the MTO process, which is an extension of fluid-bed MTG technology, has been scaled up successfully in a 4 BPD fluid-bed pilot plant at Mobil s Paulsboro Laboratory. Product yields and catalyst performance were nearly identical to those of bench top microunits. The process is currently being demonstrated in the 100 BPD fluid-bed semi-works plant in Germany. The plant was started up February, 1985 after completing modifications required to enable extended operation at MTO conditions. 

The measurement of GA and Cr is performed on a bench-top GC-MS system (e.g. Automass-2, Thermo-Finnigan or MSD 5973 Inert, Agilent) operating in the nega-... 

Recrystallisation of quantities of materials less than 1 mg (group (3)) is carried out in melting point or capillary tubes (e.g. 1.5 mm diameter), and is a much simpler operation than might be imagined. All manipulations should be carried out on a bench top covered with a piece of white glazed card or opaque glass. This ensures that all dust and dirt may be immediately observed and removed, and that the glass apparatus does not accidentally pick up dirt, bench polish, etc., small quantities of which could seriously contaminate the product. 

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