Small Laboratories

Alundum is used for highly refractory bricks (m.p. 2000-2100 C), crucibles, ref ractory cement and muffles also for small laboratory apparatus used at high temperatures (combustion tubes, pyrometer tubes, etc.). 

Under constant pattern conditions the LUB is independent of column length although, of course, it depends on other process variables. The procedure is therefore to determine the LUB in a small laboratory or pilot-scale column packed with the same adsorbent and operated under the same flow conditions. The length of column needed can then be found simply by adding the LUB to the length calculated from equiUbrium considerations, assuming a shock concentration front. 

The scale-up of filtration centrifuges is usually done on an area basis, based on small-scale tests. Buchner funnel-type tests are not of much value here because the driving force for filtration is not only due to the static head but also due to the centrifugal forces on the Hquid in the cake. A test procedure has been described with a specially designed filter beaker to measure the intrinsic permeabiHty of the cake (7). The best test is, of course, with a small-scale model, using the actual suspension. Many manufacturers offer small laboratory models for such tests. The scale-up is most reHable if the basket diameter does not increase by a factor of more than 2.5 from the small scale. 

The safety review technique is also usehil for small laboratory operations and small changes in existing processes. In these cases, the committee often consists of two or three people and any changes are often less formally recommended. 

Laboratory Information Management System. The QC lab must analy2e raw material, in-process, and finished product samples adhere to cahbration schedules record data and perform statistical analyses. These activities lend themselves to the appHcation of software packages such as a laboratory information management system (LIMS) (qv). An inexpensive LIMS is within the reach of even small laboratories. 

Manufacture. Small cylinders of hydrogen sulfide are readily available for laboratory purposes, but the gas can also be easily synthesized by action of dilute sulfuric or hydrochloric acid on iron sulfide, calcium sulfide [20548-54-3], zinc sulfide [1314-98-3], or sodium hydrosulfide [16721 -80-5]. The reaction usually is mn in a Kipp generator, which regulates the addition of the acid to maintain a steady hydrogen sulfide pressure. Small laboratory quantities of hydrogen sulfide can be easily formed by heating at 280—320°C a mixture of sulfur and a hydrogen-rich, nonvolatile aUphatic substance, eg, paraffin. Gas evolution proceeds more smoothly if asbestos or diatomaceous earth is also present. 

Available in metal only, low pressure drop, low HETP, flooding limit probably higher than Raschig rings. Not much literature data available. Used mostly in small laboratory or semi-plant studies. 

Applications for mixers in blending operations vary from small laboratory mixers to large petroleum tanks of several million gallons. Three common mixing operations are ... 

The following example helps to illustrate the use of the equations presented up to this point. An aqueous slurry was filtered in a small laboratory filter press with a pressure drop of 0.5 atm and at a temperature of 20 C. After 10 minutes, 4.7 liters of filtrate were obtained after 20 minutes, 7.0 liters were collected. From experiments at other pressures, it was determined that the cake compression coefficient was s = 0.4. We wish to determine the volume of filtrate expected after 30 minutes from a filter press having a filtering area 10 times greater than the laboratory press if the filtration is to be performed at 1.5 atm pressure. The liquid temperature will be 55 °C. We also wish to determine the rate of filtration at the end of the process. 

Primary alcohols are oxidized to either aldehydes or carboxylic acids, depending on the reagents chosen and the conditions used. One of the best methods for preparing an aldehyde from a primary alcohol on a small laboratory scale, as opposed to a large industrial scale, is to use pyridinium chloro-chromate (PCC, CsH NCrO Cl) in dichloromethane solvent. 

A large laboratory ought to have both kinds of spectrographic equipment. Any laboratory that now has equipment modifiable for x-ray emission spectrography should proceed with the modification. A small laboratory that needs diffraction equipment and can afford only one spectrograph should buy x-ray equipment. A laboratory similarly situated that haa no need of diffraction should select its spectrograph after a careful survey of its needs. We believe that all spectroscopists should become familiar with the x-ray methods described in this book. 

The design equations for a CSTR do not require that the reacting mixture has constant physical properties or that operating conditions such as temperature and pressure be the same for the inlet and outlet environments. It is required, however, that these variables be known. Pressure in a CSTR is usually determined or controlled independently of the extent of reaction. Temperatures can also be set arbitrarily in small, laboratory equipment because of excellent heat transfer at the small scale. It is sometimes possible to predetermine the temperature in industrial-scale reactors for example, if the heat of reaction is small or if the contents are boiling. This chapter considers the case where both Pout and Tout are known. Density and Q ut wiU not be known if they depend on composition. A steady-state material balance gives... 

Most kinetic experiments are run in batch reactors for the simple reason that they are the easiest reactor to operate on a small, laboratory scale. Piston flow reactors are essentially equivalent and are implicitly included in the present treatment. This treatment is confined to constant-density, isothermal reactions, with nonisothermal and other more complicated cases being treated in Section 7.1.4. The batch equation for component A is... 

A process for the depolymerisation of Nylon 6 carpet fibre in the presenee of steam under medium pressure (800 to 1500 KpA, 100 to 200 psig) is described. The feasibility of the seheme was demonstrated using a small laboratory apparatus and the best run produced a 95% yield of crude eaprolaetam. The data obtained were used to construct a computer model of the process for both batch and continuous flow stirred reactors. 6 refs. 

It is important to make a list of every task that will be performed in the laboratory, down to the smallest detail. Operations such as pH measurements, transfer of flammables from safety storage to shelf bottles, or recording observations must not be overlooked. Even in a small laboratory, the number of individual tasks will be quite substantial. 

A supervisor s office may be a separate room, although an area with partitions extending part-way to the ceiling is often just as satisfactory and less expensive. In addition, such partitioning offers the bonus of valuable extra wall space. A large window between office and laboratory is recommended for good supervision of activities. Since books and reference materials are often kept in this office, adequate space for shelves must be provided. In a small laboratory without much interference, the supervisor may simply need a desk in a corner of the room. 

Many small laboratories use kitchen cabinets, also available in wood or steel, and are quite happy with them. Normal prices of high quality kitchen cabinets are not much lower than those of the laboratory variety, but special bargains are often available. They come in far fewer types of units, which make the laboratory benches less adaptable to specific uses. Finishes are not made to resist chemicals, and the overall construction is seldom of the heavy-duty type. In a microbiological laboratory where they have been used for years, however, workers have been pleased with them. They were adequate for the light duty service and were purchased when a local dealer had a clearance sale. 

Small retail stores called science shops are found in many larger cities. While their prices may be on the high side, they offer over-the-counter service for many items needed in a hurry. They will also sell glassware by the piece rather than by the case, a service often desirable for small laboratories. 

The manner in which orders are placed varies from one laboratory to another. In a large organization, the laboratory operator wall prepare a requisition, which goes to the purchasing department, often via a department head for approval. Copies of the requisitions should be kept in the laboratory, which should also receive copies of actual purchase orders. In a small laboratory the operator may do the ordering himself. 

In a large organization, personnel records are kept in the personnel department files. In a small laboratory, they may be somewhere in the general files. Such information should be considered confidential, with steps taken to limit access. 

It becomes evident from the above that even a small laboratory will have a fair amount of time-consuming paperwork to take care of. More than one researcher has complained about the fact that record keeping interfered with creative work. Fortunately, there are ways to simplify the process. 

Scahng up will probably continue to be a problem since large reactors carmot be as efficient as small laboratory reactors. However, it may be possible to make laboratory or pilot-plant reactors that are more similar to large-scale reactors, allowing more rebable validation of the simulations and process optimization. The time from laboratory-scale to full-scale production should be shortened from years to months. 

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