Verfahrensentwicklung durch Kombination von Prozeßsimulation und Miniplant-Technik

Efficient Process Development by Combining Process Simulation and Miniplant Technique . International competition, growing ever fiercer, and product life cycles which are becoming shorter all the time demand a significant contraction times from the chemical industry, of the implementation times from the conception of a product to its market introduction. A significant contribution to rapid and cost-effective detailed planning of a new production process is provided by the combination of process simulation and an experimental technique developed within BASF AG, i.e. the ?miniplant”? technique. This article starts by demonstrating the importance of process simulation in the individual phases of process development. It explains the characteristic features of the miniplant technique, what objectives are pursued by employing his technique, and what advantages ccan be achieved, compared with setting up and operating pilot plants. Finally, two examples illustrate that it is possible, by combining process simulation and miniplant technique, to develop processes more rapidely and to scale them up directly from the laboratory to production level.     

Die vernetzung von natur- und synthesekautschuk durch schwefel,die vulkanisation als eine zwischenstoffreaktion

In this communication a summary of results on kinetical investigations of the unaccelerated and accelerated vulcanization of natural and synthetic rubber is presented. It is outlined, that the vulcanization processes are complex reactions with respect to sulfur. In a first reaction step cross links with the constitution of an alkyl alkenyl polysulfide are built up. In a second reaction step, which is a consecutive reaction with respect to sulfur, these bridge bonds are degraded, and di- and monosulfidic crosslinks are produced. At the same time cyclic, mostly five membered thioethers along the main polymer chain are formed. In the course of extensive kinetical investigations the sulfur decrease and the formation and degradation of polysulfidic bound sulfur are measured, whereby the reaction of the crosslinks with LiAl-hydride and triphenylphosphin respectively gives the background of the quantitative analysis. The quantitative explanation of the analytical results was performed (i) by means of an empirical formula and (ii) by a strong treatment of the fundamental kinetics of a reaction in which an intermediate compound (the polysulfidic bound sulfur) is involved. It is shown that in special cases (sulfur decrease of first order) an exact calculation and a proof of the sulfur balance and moreover the determination of the sulfur content as well as the concentration of crosslinks produced by a given amount of sulfur can be achieved. It is shown that the sulfur content of the bridge bonds depends on the chemical constitution of the polymer but not on the nature of the accelerating system. An accelerator chiefly governs the special kinetics of the vulcanization reaction.     

Altanlagen – Sanierung nach TA Luft durch Kombination von Verbrennung und Absorption

A waste-gas cleaning system was constructed for a group of drug production plants. The chemical – synthetic processes taking place there are characterized by inevitable emissions, mainly of vapours of organic solvents. Their concentrations vary within a wide range and at any given moment in principle remain unknown. This paper describes the initial situation and the requirements for the waste gas cleaning process, including the calculation of the gas volume flow capacity. The polluting substances were divided into two groups; for critical substances only thermal oxidation was found to be adequate, whereas for non-critical, water-soluble material, water-fed absorption columns were chosen; on one hand to avoid full exhaustion of the capacity of the thermal waste-gas system and on the other hand to offer additional possibilities in the case that this system should be out of action. The criteria for this decision as well as for the combination of one central with several decentralised cleaning units are discussed in detail. The equipment of the waste-gas emitting plants for feeding the cleaning units and the technical details thereof are described as well as the safety design. At last, experience gaine during preparation of the systems and considerations concerning further use of the thermal cleaning system are discussed.     

Kombination von mechanischer und thermischer Trocknung

Combination of Mechanical and Thermal Drying . The first part of this paper presents the various hardware approaches to combining mechanical and thermal drying. The various solutions are illustrated by applications. The second part addresses cost optimisation in the combination of mechanical and thermal drying. The approach to cost optimisation is illustrated for the example of corn starch.     

Identifizierung von molekularen Phospholipid-Species aus Schweineherz durch Kombination chromatographischer Techniken

Identification of Molecular Species of Phospholipids from Pig Heart by Combining Chromatographic Techniques. Glycero-phospholipids from subcellular organelles and membranes from pig heart were divided into subclasses. The molecular species within the main subclasses were analyzed. The phosphorus moiety had been removed by phospholipase-C and the acetylated molecules were separated in diacyl-, alkylacyl- and alkenylacyl-glycerols by thin-layer chromatography (TLC). For further identification the subclasses from the first fractionation by TLC were separated by silver ion chromatography according to their polarity. A small portion of the acetylated diradyl-species was transesterified so that the fatty acid composition could be assessed as methyl esters. The acetylated molecular species derived from glycerophospholipids were chromatographed on WCOT fused silica columns with TAP as stationary phase according to molecular weight and unsaturation. Gaschromatography (GC) of fatty acid methyl esters and dimethylacetals from plasmalogens was executed on DEGS-columns or on WCOT fused silica columns with CP-Sil 88 as stationary phase. The distribution of molecular species within a phospholipid class (PC or PE) was rather similar for the diacyl-and the alkenylacyl molecules. But the latter are more volatile. In the case of phosphati-dylcholine the composition of C₁₆-C_18-:1; C₁₆-C_18:2 and C₁₈-C_18:2 was predominant for diacyl- as well as alkenylacyl-species. In the case of phosphatidylethanolamine the fatty acid composition of C₁₈-C_20:4 and C₁₈-C_18:2 were the most important species. The composition of fatty acids in diacyl-and alkenylacyl-species is of special interest as the metabolism of diacyl-glycerophospholipids is quite different from alkenylacyl-glycerophospholipids.     

Untersuchungen zur Feinstruktur des PVC,IV. Ermittlung der Struktur von niedermolekularem PVC durch Kombination von Hydrierung, 1H- und 13C-NMR-Spektroskopie

By methanol extraction of bulk PVC 0,07% PVC of molecular weight 1500 is received, which can be hydrogenated in chloroform selectively. By combination and comparison of classical analysis, ¹H- and ¹³C-NMR-spectroscopy of the unhydrogenated and hydrogenated methanol extracted PVC of molecular weight 1500 per molecule can be determined. The remaining chain ends predominantly consist of ClCH₂CHCl? and in smaller proportion of ClCH₂CH₂-groups. It is supposed that the results detained with the PVC of M_n = 1500 are valid likewise for the original PVC of M_n = 30000.