The fulfillment of national and international climate targets as well as the forced conversion of the energy supply in Germany to the increased use of renewable energy sources require increased efforts in the area of energy efficiency. In particular, the energy consumption of large-scale industrial manufacturing processes, such as those in the metal, glass, paper and chemical industries, is the focus of attention. For the chemical industry, "energy-efficient chemical process technology, optimization of reactor technology and process chemicals, and process chain shortening" are regarded as the most important research and development priorities for reducing primary energy consumption (Federal Government Energy Research Programme 2011).
The Helmholtz Energy Alliance "Energy-efficient Chemical Multiphase Processes" is focusing on new processes and technologies for the design of chemical multiphase reaction apparatuses with the aim of optimising process control and, in particular, reducing energy requirements in synthesis and product preparation for chemical multiphase processes. The project focuses on innovative structured multiphase reactors ranging from microstructure apparatuses to large-scale reactor concepts. The design of these apparatuses on the basis of reaction- and process-adapted design strategies is a central working point. New catalyst structures based on ceramic and metallic monoliths and foams as well as their production and characterisation are researched. Methodical work includes the characterisation of catalysts and modular reactor components, the cross-scale modelling of hydrodynamics, mass and heat transport as well as chemical reactions from the pore structure of the catalyst to the reaction apparatus and the development of new measurement techniques for multiphase processes. The project is spanned by dedicated system analyses to assess the economic efficiency and sustainability of new reactor technologies over the entire life cycle.
Work of the Institute of Multiphase Flows within the Energy Alliance
Structured packings are widely used in multiphase apparatuses. They can enhance mass transfer processes and thereby affect hydrodynamic parameters like gas holdup, pressure drop and local flow fields. In this work package novel structures like periodic open cell structures (pocs) and foam like structures are used in a bubble column operation. The structure elements are additively manufactured by stereolithography to precisely adjust geometry parameters. The goal of this research is to identify the influence of defined geometry parameters on the mass transfer performance of a structured element with respect to the resulting pressure drop and energy dissipation. An optimized structure element regarding the ratio of mass transfer performance and energy dissipation for a bubble column apparatus is intended. Thereby the optical measurement technique Laser Induced Fluorescence is used to relate the mass transfer performance with the local concentration fields for phenomenological explanation.
Identifying the geometry parameter field and manufacturing of structure elements
Manufacturing of transparent structure elements and adaption of the laser optical measurement technique Laser Induced Fluorescence
Measurement of local concentration fields in structure elements
Measurement and calculation of energy specific mass transfer performance for the parameter field
Foam like structure element (left) and periodic open cell
structure with pyramidal base cell, both with 5 ppi cell concentration.