Semi-technical plant

Column heads of semi-technical plants are made up of separate condenser and reflux units. The valves are operated mechanically and, more commonly, electro-magnetically. Their operation is similar to that in laboratory column heads (Figs. 306, 247). The valves are controlled automatically by means of electromagnets, electromotors or pneumatic drives (Fig. 248). For the automatic division of liquid, however, the swinging funnel is chiefly used (Fig. 142) which is actuated by an electromagnet placed outside the column wall. With the magnet switched on the distillate is taken off laterally. 

For semi-technical plants of glass, short-necked round-bottomed flasks of capacities up to 41 and three-neck round-bottomed flasks of capacities up to 101 (TGL 10102) are available. The glassware manufacturers can now offer spherical distilling flasks and cylindrical vessels with capacities up to 200 and 3751, respectively. Connection pieces may be placed at the top, at the side or at the bottom. Cylindrical vessels are usually provided with caps which hold the connection pieces. 

Of the non-cylindrical forms of packing the following are emploj-ed in the laboratory and in semi-technical plants. 

Adsorption capacity of carbons depends on equilibrium concentration in static conditions. At concentration of 0.2 mg/dm it may be even 3 times greater than in dynamic conditions. When equilibrium concentrations in static conditions decrease, these differences also decrease, and at 99% reduction of SLS quantity, these values are similar. Carbons of plant origin show the opposite dependence. For example, adsorption capacity of Z—3 carbon in dynamic conditions is 6 times greater than in static processes. Lower adsorptivity of carbons in dynamic conditions results from short time of contact and small depth of bed. Because of this, determination of bed depth is important from economic point of view. Studies of time of adsorption have shown, that in order obtain concentration of 0.2 mg/dm of SLS in effluent about 60 hrs are required and to total exhaustion of bed about 300 hrs. These times are longer for molecules of greater size and for lower concentrations and, of course, in semi-technical scale studies, where depth of bed should be similar to depth of adsorptive filter (1 —4 m). Because of this, to shorten the reaction times low depth of bed was proposed for primary evaluation of carbons [39]. Studies should also take into accoimt differences in filtration rates (adsorptive filters 5 — 30 m/h, mechanical—adsorptive filters up to 10 m/h) in technical conditions of water supply system. 

Pyrolysis as a waste treatment method has made considerable progress during recent years. After laboratory and semi-technical scale testing, several demonstration plants have been set up. Others are in the planning or construction stage. 

KIRCHHOFF, R., et al.. Operation of a Semi-Technical Pilot Plant for Nuclear Aided Steam Gasification of Coal, Nucl. Eng. Des. 78 (1984) 233-239. 

For the uses of semi-technical glass apparatus in the laboratorj and in pilot plants the reader is referred to the pajrers of Rieger [5]. By using special tjqres of glass it is possible to make apparatus capable of withstanding distillation pressures up to 4.3 kg/cm [6]. The use of porcelain in the laboratory has been discussed by Kaminel [7]. 

Glass taps with greased ground surfaces, in particular with dimensions > 40 cm, are unsuitable for semi-technical or pilot plants. In these cases valves are used instead of taps, especially since the combination of glass and Teflon has made possible many... 

However, heat exchangers for semi-technical and pilot plants have to be calculated exactly, the more so because the cooling surfaces are assem bled from standardized components. For this purpose, the manufacturers of glass components give the heat tr ansfer coefficients k as listed in Table 67. 

For semi-technical and pilot plants the still heads are usually made up of the same components as those required for the assembly of lengths of piping (c/. chap. 7.2). Gases and liquids are introduced into the columns by means of feed lines or tubes provided with an annular rose (Figs. 138 and 142). 

Pilot plant and semi-technical distillation apparatus made of glass requires special connections, clamps and frameworks. It may suffice here to refer the reader to the catalogues of the glassware manufacturers. Some firms even send crews for the assembly of apparatus. As an example Fig. 424 shows a framework of galvanized tubes joined by means of sockets with Inibus screws. 

As a result of the concurrent progress on the polymerization side, Ludwigshafen and Leverkusen agreed in July 1929 to build a semi-technical works plant for Buna at Knapsack, alongside the carbide works. This plan was blocked by Carl Krauch of Oppau, largely because he wanted to wait until Oppau s methane-to-acetylene electric arc process was ready. A few months later, the Buna program was effectively halted by the onset of the Depression, which soon reduced natural rubber prices to minimal levels. When the production of synthetic rubber was revived in Hitler s Third Reich, the weak Buna, which was a sodium-polymerized polybutadiene, had been displaced by the superior copolymers of butadiene with styrene (Buna S) and acrylonitrile (Buna N or Perbunan). 

Figure 17.2 Inocermic semi-technical pervaporation plant (UK). Reprinted from J. Caro, M. Noack and P. Kolsch, Zeolite membranes from the laboratory scale to technical applications, Adsorption 11, 215-227, 2005, with permission of SpringerLink.

As a result of the work described above a decision was taken in 1966 to scale up the polyether synthesis and semi-technical and pilot plant scale units were built on the Plastics Division Headquarters site at Welwyn Garden City. This was not done without considerable reservations, but the decision to concentrate this development at Welwyn enabled the research team to dominate technological development of the process to monomers and polymers in a way that would not have been possible on a production site. 

In anticipation, in 1946 Shell gave a grant of 2 million guilders - at that time a considerable amount of money -to the TUD. One half of this amount was to be spent for the extension of Waterman s semi-technical facilities, and the other half on the founding of a new building with equipment for research and pilot plant operation in physical technology. Concurrently, in the latter field, the university had to provide for a professorship and the necessary staff. In 1947 the author of this paper was appointed to this chair, which he held until 1963. As a rather unique feature, this nomination involved the staff... 

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