A Catalytically Active Membrane Reactor for Fast, Highly Exothermic, Heterogeneous Gas Reactions. A Pilot Plant Study

Membrane reactors have been frequently studied because of their ability to combine chemical activity and separation properties into one device. Due to their thermal stability and mechanical strength, ceramic membranes are preferred over polymeric ones, but small transmembrane fluxes obstruct a widespread industrial use of a membrane reactor. Consequently, a bench-scale membrane reactor with a tubular, macroporous membrane (dp = 700 nm) was developed in order to attain increased fluxes. A cooling pipe was concentrically placed inside the tubular membrane to remove heat from the membrane surface, so the present membrane reactor was suitable to conduct exothermic reactions. As a model reaction, the heterogeneous oxidation of carbon monoxide over platinum, with separated feed of carbon monoxide and oxygen, was performed in the present setup. First, the present membrane reactor was characterized by the determination of the transport parameters, structure parameters of the membrane, and the external transfer coefficients. Subsequently fluxes of the reactants and products were measured over a wide range of process conditions. Especially the influence of a transmembrane pressure difference was studied extensively. Furthermore overall conversion of carbon monoxide was measured under various process conditions, and the results were compared with the simulations of a simplified, overall reactor model. From the results of the present investigation, it could be concluded that the application of a pressure difference over the membrane turned out to be a major process control parameter. It increases the product yield and preferentially directs the fluxes toward one side of the membrane. It was shown that even for macroporous catalytic membranes substantial pressure differences are allowed without any slip of unconverted reactants through the membrane. Furthermore, high degrees of conversion were observed in the present setup, and the simulations of the overall reactor model were in reasonable agreement with the experimental data. The overall model contained no adjustable parameters. From this study, the catalytically active, ceramic membrane reactor with separated feed of reactants turned out to be highly flexible and easy to control.

ICIE 1.0:a novel tool for interactive contextual interaction explanations

\u3cp\u3eWith the rise of new laws around privacy and awareness, explanation of automated decision making becomes increasingly important. Nowadays, machine learning models are used to aid experts in domains such as banking and insurance to find suspicious transactions, approve loans and credit card applications. Companies using such systems have to be able to provide the rationale behind their decisions; blindly relying on the trained model is not sufficient. There are currently a number of methods that provide insights in models and their decisions, but often they are either good at showing global or local behavior. Global behavior is often too complex to visualize or comprehend, so approximations are shown, and visualizing local behavior is often misleading as it is difficult to define what local exactly means (i.e. our methods don’t “know” how easily a feature-value can be changed; which ones are flexible, and which ones are static). We introduce the ICIE framework (Interactive Contextual Interaction Explanations) which enables users to view explanations of individual instances under different contexts. We will see that various contexts for the same case lead to different explanations, revealing different feature interactions.\u3c/p\u3