Darf ein Produkt über das Abwasser entsorgt werden?

Prior to releasing waste from consumer goods and industrial chemicals into sewage, it is imperative to have their behaviour in sewage purification plants tested in adequate installations. EMPA specialists conduct such analyses, allowing to gather reliable data about the sewage compatibility of this type of product waste. The present study describes efficient test procedures in this range and EMPA experienced assessment criteria

Large Vibrations on a Centrifugal Compressor Caused by High Windage Heating on a Flexible Coupling–Root Cause Analysis and Solutions

Case StudyBackground: 2 parallel trains consisting of a Low Pressure (LPC) and High Pressure (HPC) compressors were supplied for an offshore reinjection application near the coast of Angola. During the commissioning on site large lateral vibrations were observed at both units on the Bearings “Drive-End”of the Pinion and “Drive-End”of the LPC. Several balancing runs of the trains on site were necessary to operate both units and allow for injection gas. To avoid repeated field balancing (if coupling or rotor must be removed/reinstalled during future maintenance) the coupling and oil system needed to be re-designed

Damaged Compressor Stator Parts Resulting From Operation In Deep Choke

Case Stud

Wie vollständig ist der biologische Abbau: Ermittlung und Analytik refraktärer Verbindungen am Beispiel von linearem Alkylbenzolsulfonat (LAS)

Linear alkylbenzenesulfonate (LAS) is the worldwide most used synthetic surfactant. Its elimination in activated sludge goes nearly to completion. But in laboratory test systems a well primary but no total biodegradation, measured by removal of dissolved organic carbon (DOC), has been found till now. On a new test system to detect refractory organic carbon (ROC) a commercial LAS yields > 5% of ROC. With HPLC and GC/MS analysis the refractory organic compounds are determined as different isomers of sulfophenylcarboxylates and carboxylated dialkyltetralinesulfonates. Dialkyltetralinesulfonates are beside branched alkylbenzenesulfonates known impurities in commercial LAS. These impurities undergo a complete primary biodegradation in the used test system. It is estimated, that the detected refractory sulfophenylcarboxylates derived from branched alkylbenzenesulfonates and not from LAS. The test to detect ROC effects on the base of a trickling filter, where the test substance is dissolved in a mineral salt solution and trickles over activated sludge, which is fixed on a support. Eluate derived from the trickling filter is readded with new test substrate and fed again to the filter. Readdition is repeated till the content of nondegraded parts in the eluate is high enough. Then the eluate is fed to the filter without substrate readdition as long as the remaining organic carbon in the eluate is constant. The residual DOC is called refractory

Stability Considerations - A Simplified Approach

TutorialTutorial 2: In many cases it is necessary to judge the stability behavior of a specific compressor. This might be the OEM checking the feasibility of a proposed compressor layout or it might be the user judging one of his machines which causes troubles in operation. API 617 suggests a stability level I or level II analysis. The shortcoming of the level I analysis is that it considers only the global cross-coupling stiffness of the entire stages neglecting the actual seal design of a compressor. Thus the damping of a machine is always decreasing with increasing load which is not reflecting the true stability behavior of modern turbo compressors. On the other hand a level II analysis requires detailed insight into the machine design which might not be defined at that time or which is not known to the user. To overcome these problems this tutorial proposes a different kind of stability check which only requires a minimum of operational and design data and delivers a comprehensible and (relatively) reliable picture of the stability behavior of the investigated compressor. This tutorial derives the used stability criterion and explains the effect of the circumferential speed of the gas in the seal gap on the rotordynamic behavior. Finally it presents example calculations for different seal configurations and compares the resulting stability judgments to the results of the classical API level II analysis and to the results of experimentally determined rotor damping

Stability Considerations - A Simplified Approach

Tutorialpg. 246-253In many cases it is necessary to judge the stability behavior of a specific compressor. This might be the OEM checking the feasibility of a proposed compressor layout or it might be the user judging one of his machines which causes troubles in operation. API 617 suggests a stability level I or level II analysis. The shortcoming of the level I analysis is that it considers only the global cross-coupling stiffness of the entire stages neglecting the actual seal design of a compressor. Thus the damping of a machine is always decreasing with increasing load which is not reflecting the true stability behavior of modern turbo compressors. On the other hand a level II analysis requires detailed insight into the machine design which might not be defined at that time or which is not known to the user. To overcome these problems this tutorial proposes a different kind of stability check which only requires a minimum of operational and design data and delivers a comprehensible and (relatively) reliable picture of the stability behavior of the investigated compressor. This tutorial derives the used stability criterion and explains the effect of the circumferential speed of the gas in the seal gap on the rotordynamic behavior. Finally it presents example calculations for different seal configurations and compares the resulting stability judgments to the results of the classical API level II analysis and to the results of experimentally determined rotor damping

Rotordynamic Stability Tests On High-Pressure Radial Compressors.

LecturePg. 115-122This paper describes extensive measurements on high-pressure radial compressors with rated discharge pressures of more than 400 bar (5800 psi). The purpose of the measurements was to deterine m the damping behavior of the entire machines as a function of several parameters such as discharge pressure, bearing distance, labyrinth types, or configurations of anti-swirl devices. In the past, most of the rotordynamic damping measurements have been carried out by universities on test rigs specially designed to measure labyrinth forces, which are mainly responsible for the change in damping at high pressures. Unfortunately, all these tests have been carried out at pressure levels far below the levels of industrial applications. Thus, the presented tests on complete compressors, ready for offshore applications, are certainly unique. The tests showed a generally conservative prediction of the damping. At higher pressures, a drop of the first natural frequency of the shaft was encountered. This effect could be attributed to the used labyrinth type

Turbomachinery Bearings and Annular Seals

Discussion Grou

Soziales Netzwerk und soziale Unterstützung bei Ehepaaren: eine Pilotstudie

Soziales Netzwerk und Soziale Unterstützung stellen zwei wichtige Sozialkonstrukte, d.h. Indikatoren der sozialen Datenebene dar. Verschiedene Befunde liegen zu Ehepaaren vor, doch fehlen bisher Studien zu länger dauernden inhaltlichen Beziehungen. Die vorliegende Pilotstudie ist daher diesem Thema gewidmet. Es wird dabei zwischen der Untersuchungseinheit Paar und der Einheit Einzelperson unbterschieden. 20 Ehepaare, die die seit mindestens 5 Jahren standesamtlich verheiratet waren, wurden mittels Fragebogen zum Sozialen Netzwerk und zur sozialen Unterstützung untersucht. (TL2

Large Vibrations on a Centrifugal Compressor Caused by High Windage Heating on a Flexible Coupling–Root Cause Analysis and Solutions

Case StudyBackground: 2 parallel trains consisting of a Low Pressure (LPC) and High Pressure (HPC) compressors were supplied for an offshore reinjection application near the coast of Angola. During the commissioning on site large lateral vibrations were observed at both units on the Bearings “Drive-End”of the Pinion and “Drive-End”of the LPC. Several balancing runs of the trains on site were necessary to operate both units and allow for injection gas. To avoid repeated field balancing (if coupling or rotor must be removed/reinstalled during future maintenance) the coupling and oil system needed to be re-designed