摘要:

AbstractEffect of corrosion and fluctuating mechanical stress on the fatigue properties of construction units. Considerable damage is still being caused by fatigue corrosion resulting from fluctuating stresses in construction units, even though such a source of damage has been known for more than half a century. More than 10% of the total corrosion damage encountered in chemical engineering stems from this type of transcrystalline crack. The particular difficulties met with in attempts to guard against such material damage rest, on the one hand, in the multiplicity of factors influencing the loss of strength and, on the other, in the problems associated with the applicability of laboratory results to the behaviour of constructional units. In this paper the influence of corrosion medium, limiting value of stress cycle endured, thickness of construction unit, frequency, mean stress and crack‐propagation characterization on stability towards vibration corrosion is dealt with and shows the design engineer how the relevant data concerning component behaviour are to be handle

ISSN:0009-286X    

DOI:10.1002/cite.330520202

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330520203

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractIndustrial application of zeolitic catalysts in hydrocracking. For maximum production of gasoline by hydrocracking using zeolite type catalysts two cracking schemes are presented and the operation conditions, feedstocks, yields, and material balances are discussed. The advantages of zeolitic hydrocracking catalysts are outlined. The main catalyst parameters controlling activity and selectivity are described and a scheme for the preparation of zeolitic catalysts is given, which illustrates the superiority of zeolitic hydrocracking catalysts over amorphous ones. Finally, the hydrocracking of residues is reviewed and a typical process together with the product characteristics and yields obtained is described.

ISSN:0009-286X    

DOI:10.1002/cite.330520204

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractDetermination of optimum operating conditions of industrial fluidized bed reactors. Fluidized bed technology has long been successfully used in numerous industrial processes. Nevertheless, the design and optimization of fluidized bed reactors still give rise to considerable difficulties owing to the complex nature of the gas/solids flow. Advances in the mathematical description of fluidized bed reactors have now been made by formulation of a model describing the catalytic reaction in a gas/solids fluidized bed in terms of absorption of reactants from the bubble phase with subsequent pseudohomogeneous reaction in the catalyst suspension surrounding the bubbles. Empirical relations are reported for mass transfer, specific transfer area, and bubble gas hold‐up, taking into account the influence of fluidized‐bed geometry which is of great importance in scale‐up. The state of development reached and the practical use of the model is demonstrated by evaluation of various reactions taken from the literature. Any desired reaction mechanism can be incorporated into the model. It is shown for the example of the selectivity behaviour of a system of consecutive reactions that a detailed knowledge of the reaction kinetics is a necessary condition for the design and operational optimization of industrial fluidized bed rea

ISSN:0009-286X    

DOI:10.1002/cite.330520205

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractExplosion hazard analysis of inflammable gas released spontaneously into the atmosphere. The processes of flash evaporation, atmospheric vapour cloud formation ignition and explosion after the bursting of vessels containing liquefied gas have been studied by model experiments with propylene heated up to 70°C and pressurized to 60 bar. The experiments have shown that a blast wave with considerable peak pressure in the vicinity of the vessel is produced already by flash expansion of the propylene. The experimentally determined decrease of peak pressure with growing distance could be scaled up to vessels of arbitrary size and different propylene temperatures. Scaling laws could be established as well for the calculation of peak pressure and positive pressure duration of the deflagration wave as functions of released mass and distance. The experiments have not revealed any evidence of a detonation process even when the cloud was ignited by an explosive charge

ISSN:0009-286X    

DOI:10.1002/cite.330520206

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractQuantitative risk analysis in the chemical industry. Consideration of risks on a qualitative basis is a useful, generally applied tool in safety engineering. However, attempts to quantify risk create problems. Quantifying studies have been published concrning nuclear and chemical plant, storage tanks, and port and transport facilities. At present, attempts are also being made in Germany to demonstrate that quantitative risk analysis is also possible for chemical processes. Instead of relying on past empirical values, an ab initio determination of risk from model calculations is being tried. A theoretical basis is already available for such calculations. However, practical execution and simplification of the complicated methods leads to numerous problems which are discussed in this paper. With the aid of selected examples attention is focussed on the following problems: (1) consideration of maintenance; (2) quality of starting data; (3) predictive power of weak‐point analysi

ISSN:0009-286X    

DOI:10.1002/cite.330520207

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractDuties, performance, and objectives of maintenance services in the chemical industry. In the West German chemical industry, about DM 5000 million will be spent on maintenance in 1979. This figure is only slightly less than the amount to be spent on reserch or capital investment. The expenditure ensures peak performance from production installations and the infrastructure as a whole and a high level of plant safety. Increasing costs and reduced earnings demand greater efforts on the part of all maintenance services. The remedy in the past lay in preventive maintenance, but much higher targets are being set today: planning of easily maintainable plants, early recognition of damage; rationalisation of maintenance techniques; work preparation and scheduling; quality control; integration of spare parts inventories; standardisation, etc. The difficult task for the future will be to find solutions to the rising labour costs and various human problems.

ISSN:0009-286X    

DOI:10.1002/cite.330520208

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractQuestions of noise reduction in the chemical industry (noise levels inside and outside industrial sites). In the chemical industry there are hardly any noise problems as far as working conditions are concerned. However, certain difficulties are to be expected in the neighbourhood of chemical plant. Open‐air plants require special nosie reduction measures at many individual noise sources. Safety aspects must have priority. The increased demands necessitate inclusion of piping and equipment in acoustic planning. There should be adequate transition zones separating industrial and residential areas, but owing to lack of town planning desirable screening distances hardly exist. New plants can now be built with noise levels some 7 to 10 dB (A), in certain cases even more than 10 dB (A), lower than ten years ag

ISSN:0009-286X    

DOI:10.1002/cite.330520209

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330520210

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330520211

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY