Verbrennungsanlage mit Rauchgaswäsche für die Beseitigung von Chemie-Abfällen

Incineration plant with flue-gas scrubbers for disposal of chemical waste . Incineration plant No. II installed at the Bayer Facilities at Leverkusen/Germany has been in regular operation since November 1977 after a previous one-year period of testing. About 25 000 t of industrial waste per year can be burnt in this plant, simultaneously producing nearly 140 000 t of steam. The plant consists of a bunker building, a rotary kiln and secondary combustion chamber, including all the feeding equipment for solid, viscous, and liquid wastes, as well as a boiler, an electrostatic dust precipitator, and a wet gas cleaning unit. This latter unit consists of an injection cooler (quencher), two rotary scrubbers, and a jet scrubber. The cleaned flue gas is reheated in two heat exchangers and is discharged from a suction blower through a 100 m high chimney into the atmosphere. Around the chimney several measuring instruments are installed to check and continuously record the type and amount of emission. The scrubber water is sent to the company waste water treatment plant; the solid ashes and dust are dumped separately. The average incineration costs are DM 400 per ton of waste.     

Dynamische Simulation von Wärmeübertragern

Simulation of the Dynamic Behaviour of Heat Exchangers . Four models for heat exchangers under transient conditions are presented. Three of them describe a single phase heat exchanger, and the forth one is used for the simulation of a condenser. All models are of intermediate complexity and valid for simulation of both single heat exchangers and chemical processes. They use distributed variables and incorporate the calculation of local heat transfer coefficients so that temperature profiles over the apparatus can be determined in addition to the transient behaviour of the outlet variables.     

Elektrohydraulische Zerkleinerung von carbonfaserverstärkten Kunststoffen für das Carbonfaser‐Recycling

According to investigations conducted on the median fiber length, mass‐specific energy consumption, Young modulus and minimal content of epoxy adhesion, the extraction of free carbon fibers from carbon fiber reinforced polymers by electrohydraulic fragmentation can be considered as downcycling. This means that the gained secondary raw material has a lower product quality than the virgin material and the energy required for its production is higher than for the virgin fibers.     

Die Bedeutung von Spalten zwischen Rohren und Rohrboden für das betriebliche Verhalten von Wärmeaustauschern

Importance of crevices formed between tubes and tube plate for the operational behaviour of heat exchangers . It must be guaranteed by construction and manufacture of heat exchangers that primary and secondary medium are completely separated from each other. When this requirement is fullfilled, the operational use of heat exchangers can be impaired by corrosion reactions within the crevice formed between tube and tube plate which may result in corrosion damage. The various techniques which are in use to connect tubes and tube plate and which are described in the present report, must be valued with respect to the tightness of the connection as well as to the formation of crevices between tubes and tube plate. Corrosion resistant copperbase alloys and stainless steels are the most important materials which are in use for the construction of heat exchangers. The mechanisms of crevice corrosion with unalloyed and low alloy carbon steels, stainless steels, and mixed connections between tube and tube plate with these materials are described in detail. Crevice corrosion may be caused also by the formation of galvanic cells between materials of differing electrochemical response. Furthermore, the concentration of aggressive media in crevices between tubes and tube plate can lead to corrosion damage of heat exchanger tubes. For the service operation of heat exchangers without any hazard of corrosion damage in crevices between tubes and tube plate, such crevices must be avoided by proper construction and manufacture. As a model for suitable measures to avoid crevices, the manufacture of steam generators for PWR's is described.