Laboratory unit operation

Since our laboratory frequently uses HPLC for the final determination step, those assays were first chosen for automation. Each procedure was subdivided into discrete laboratory unit operations for final inclusion into the Zymate program. Each of these operations was also assigned to a module such as hand, master lab station, or blender. The sequence of operations and modules was then merged to arrive at a final procedure. This final procedure was then "taught" to the robot using a series of user-defined terms which could then be coupled into a program for that sample preparation. Since many of the laboratory operations are the same for many assays, an analyst needs to define only a limited number of terms to be intermixed into a variety of programs. 

List sequentially a set of laboratory unit operations that might l>e used to... 

The centrifugal microfluidic platforms utilize primarily the rotationally controlled centrifugal field in combination with capillary forces to network a range of laboratory unit operations... 

Analytical methods also vary from one another, since different techniques and instrumentation are used for each method. Despite this, such methods can be formalized as a sequence of steps, i.e. laboratory unit operations, operating different instruments and apparatuses. Furthermore data processing is very similar for all methods. 

Crystallization is one of the oldest unit operations in the portfoho of industrial and/or laboratory separations. Almost all separation techniques involve formation of a second phase from a feed, and processing conditions must be selected that allow relatively easy segregation of the two or more resulting phases. This is a requirement for crystallization also, and there are a variety of other properties of the sohd product that must be considered in the design and operation of a crystallizer. Interactions among process, function, product, and phenomena important in crystallization ate iRustrated in Figure 1. 

The laboratory units that have been employed to date for these experiments were designed to operate at a total system pressure of about 100 kPa (1 atm) and at near-ambient temperatures. In practical situations, it may become necessaiy to design a laboratory absorption unit that can be operated either under vacuum or at elevated pressures and over a reasonable range of temperatures in order to apply the Danckwerts method. 

Should the additional component compositions be required to fully understand the unit operation, the laboratory may have to develop new analysis procedures. These must be tested and practiced to establish reliabihty and minimize bias. Analysts must sribmit known samples to verify the accuracv. 

The ROTOBERTY internal recycle laboratory reactor was designed to produce experimental results that can be used for developing reaction kinetics and to test catalysts. These results are valid at the conditions of large-scale plant operations. Since internal flow rates contacting the catalyst are known, heat and mass transfer rates can be calculated between the catalyst and the recycling fluid. With these known, their influence on catalyst performance can be evaluated in the experiments as well as in production units. Operating conditions, some construction features, and performance characteristics are given next. 

The SIMULAR, developed by Hazard Evaluation Laboratory Ltd., is a chemical reactor control and data acquisition system. It can also perform calorimetry measurements and be employed to investigate chemical reaction and unit operations such as mixing, blending, crystallization, and distillation. Ligure 12-24 shows a schematic detail of the SIMULAR, and Ligure 12-25 illustrates the SIMULAR reaction calorimeter with computer controlled solids addition. 

Chemical Flowsheet Basic unit operation selection with flow rates, conversion factors, temperatures, pressures, solvents and catalyst selection Process synthesis route Laboratory and pilot scale trials Knowledge of existing processes... 

Adopted from R. Bertea, Incorporation of Occupational Safety and Healtli Into Unit Operations Laboratory Courses, NIOSH, Cincinnati, 1991... 

A third factor affecting the quantity to be processed is the scale of the processing operation. A laboratory-scale operation will typically require less sample than a pilot-scale operation and much less than a commercial scale operation. Throughout the process, each unit operation must be supplied sufficient material to operate the process adequately while providing representative samples from the process. 

New processes, developed from laboratory research, through pilot plant, to a commercial process. Even here, most of the unit operations and process equipment will use established designs. 

A quarterly publication of the American Chemical Society. It reports research studies on various processes and unit operations. It is mainly concerned with laboratory developments. 

Mobile Medical units with Clinic for First aid treatment Laboratory Diagnostic units operating theater hospital, specifications for treatment of patients affected by chemical agents (indication, decontamination). 

Drying, usually by physical methods, is one of the most common unit operations in both laboratory or industrial scale process chemistry, and since heating is usually employed to remove volatiles, thermally unstable materials may decompose if overheated. As a light-hearted example, when a faulty oven thermostat led to overheating of mercuric thiocyanate, a monstrous Pharaoh s serpent resulted. Drying moist cadmium propionate in an electric oven led to explosive ignition of the diethyl ketone vapour produced as an unforeseen by-product. Drying 3,5-dinitro-2-toluamide had more serious consequences. 

Since the oxidation of SO to SO is a step in the operation of SOx catalysts, an increase in oxygen concentration should favor the reaction, and thereby increase the efficiency of SOx catalysts. The evidence indicates that this occurs. Baron, Wu and Krenzke (9) have shown that an increase in excess oxygen from 0.9% to 3.4% resulted in a 20% reduction in SOx emissions. This was for a steam-deactivated catalyst in a laboratory unit at 1345 F (no combustion promoter). 

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