Plants, laboratory

Figure 2.8.1 shows a typical installation for flasks and other containers in which the product is to be dried. The condenser temperature for this plant is offered either as -55 °C or as -85 °C. For this type of plant, a condenser temperature of -55 °C is sufficient as this temperature corresponds with a water vapor pressure of approx. 2.1 10 2 mbar, allowing a secondary drying down to approx. 3 10-2 mbar. This is acceptable for a laboratory plant, in which the limitations are not the condenser temperature but the variation of heat transfer to the various containers, the rubber tube connections and the end pressure of the vacuum pump (2 stage pump, approx. 2 10 2 mbar). Figure 2.8.2 shows that these units are designed for very different needs. The ice condenser in this plant can take up 7.5 kg of ice at a temperature down to -53 °C. 

Bells with baseplate are used for laboratory plants they are cost-effective, but cannot be sterilized by steam. Figure 2.10 shows a typical bell installation in which the shelves are usually heated, but cooling can be provided as well as a closing mechanism for vials. 

As indicated by the title of this section, the manufacturers of such plants attempt to make them flexible for different applications by using a modular concept. Often, the basic unit consists of a condenser, a vacuum pump and a vacuum gauge, to which various drying systems can be added e. g. manifolds for flasks, ampoules or vials, baseplates with belljars or small chambers with temperature-controlled shelves. The following qualities could be important in selecting the most suitable laboratory plant ... 

The process data from manifold installations can hardly be transferred to chamber-type plants. This applies, practically, also to the process transfer from belljar-type installations to chamber plants. Results obtained in laboratory plants of the chamber type must be analyzed carefully, if they are be transferred to another plant. If the product, the layer thickness of the product and the vials or trays are identical, the following conditions should be observed and compared ... 

The shelf temperature and the controlled operation pressure must be controlled in such a way, that TKt in the laboratory plant is stable and measured with a standard deviation less than = 0.5 °C. 

It is likely asked too much of most laboratory plants, if used as pilot plants for production process development. The best application of laboratory plants is the freeze drying of preparations and products which do not require to be operated within small tolerances, but can be dried under noncritical process data. 

This step is so important that some laboratory plants, and usually all pilot and production plants, are equipped with respective mechanisms. The principle is simple The shelves are connected flexibly with inlet and outlet of the brine. The shelves are pressed together, one after the other, by a plate, which is moved by an external force in this way the stoppers are pushed into the closed position. If the pressure necessary for this stopper movement is 1 kg per stopper, the resulting total force for 100 vials per shelf is 100 kg, but if 10 000 vials are loaded per shelf, the total force is 10 tonnes, which has to be applied evenly in order to avoid vials breakage. 

Nitroglycerine (C3H5N309) (2.6) was first prepared by the Italian, Ascanio Sobrero in 1846 by adding glycerol to a mixture of sulfuric and nitric acids. In 1863, a laboratory plant was set up to manufacture nitroglycerine by the Nobel family. In 1882, the Boutmy-Faucher process for the manufacture of nitroglycerine was developed in France and also adopted in England. 

The sputtcr-ion pumps provide a vapor-free system giving a so-called dry vacuum, and they are often incorporated in plant with molecular sieve sorption as the hacking pump, For medium-size laboratory plant able to provide ultrahigh vacuum they are most attractive. Probably their chief... 

The following qualities could be important in selecting the most suitable laboratory plant ... 

Beet sugar syrups Laboratory plant Pilot plant Unit... 

In a process of isomerization of a sulfanilamid compound, the methods of both the steepest ascent and simplex optimization have been analyzed. Trials were performed in a laboratory plant. Table 2.214 shows FUFE 22 with application of the method of steepest ascent. Maximal yield by this method was 80%. Table 2.215 shows the application of simplex method (k=2) to the same process. The position of initial simplex corresponds completely to the position of trials of factor design Fig. 2.54. 

Depending upon the research facilities and expertise available to a laboratory, plant analysis can be carried out to concentrations as low as ng kg . Stoeppler (1991) has defined different categories and analytical tasks depending on their order of difficulties ... 

Blum, U. 1999. Designing laboratory plant debris-soil bioassays some reflections. In Inderjit, Dakshini, K. M. M., Foy, C. L. (Eds.), Principles and Practices in Plant Ecology — Allelochemical Interactions. CRC Press, Boca Raton, FL, 17-23... 

The desired primary liquid products of biomass pyrolysis react readily in secondary cracking reactions, shifting the product yield from liquids to gases. Those cracking reactions are assisted by contact of the volatiles to the remaining solids, which can be reduced significantly by running the fast pyrolysis in a reaction cyclone [79, 80]. A simplified flow sheet of such a laboratory plant for the fast pyrolysis of biomass is shown in Fig. 15.9. 

Figure 5.14 Microprocess laboratory plant for ozonolysis of steroids using a falling-film microreactor (by courtesy of K. Jahnisch/LIKAT) [50],...

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