No abstract

A foaming problem in an industrial-size deacidifier (packed column) within the ammoniahydrogen sulfide circulation scrubbing process (AS process) on a specific site is experimentally investigated. The foamability of solutions is successfully assessed in a small test cell, and the Bikermann coefficient is calculated to characterize the foaminess behavior. The investigations revealed that filtration of the real sour water taken from the specific site does not alter foaming characteristics. Impurities, especially phenol and its derivatives, cresols, are found to highly contribute to foaminess behavior. Experiments in a pilot plant revealed higher pressure drop and lower flood point data. Critical spots of foam formation are identified, and design suggestions for column internals are given.

In this work, a systematic approach based on nonlinear experimental design as an efficient tool for the validation of kinetic models is proposed which has the objective of computing experimental layouts, setups, and controls in order to optimize the statistical reliability of parameter estimates from the resulting experimental data. Furthermore, because the optimum experimental design is dependent on the values of the parameters, a sequential design is proposed. This represents an interaction between proposed experiments (e.g., inlet temperature and concentration), their evaluation, parameter estimation, and new design information such as reactor layout, sampling points, and temperature measurement positions. This follows an iterative procedure until all parameters achieve a prescribed statistical quality. Because of the fact that the overlaying optimization problem contains a highly nonlinear objective function, a hybrid optimization framework is also proposed to overcome the problem of local minima. To show the efficiency of the developed framework, it has been applied to the contact reaction. This reaction is a basic step in the sulfuric acid production and is carried out in a catalytic fixed-bed reactor called the contact horde.

In der Kokereitechnik fallen belastete Abwässer an, die effizient behandelt werden müssen, um die Umwelt nicht zu belasten und den gesetzlichen Verordnungen gerecht zu werden. Hierzu ist ein genaues Prozessverständnis notwendig. Aufgrund der Vielzahl an möglichen Modifikationen nehmen Schwefelverbindungen eine Sonderstellung ein, weswegen die Kenntnis der verschiedenen Reaktionspfade und ‐kinetiken für die Auslegung der Apparate essenziell ist. Mittels Parameterschätzung und Modeldiskriminierung werden in diesem Beitrag Kinetiken anhand von Experimentaldaten ermittelt und Reaktionsschemata der Nassoxidation von Thiosulfat bewertet, um den Konzentrationsverlauf aller Spezies hinreichend genau beschreiben zu können.