Tools and Methods for an Improved Fluid Dynamic Design of Column Trays with Fixed and Push Valves
Motivation and Objective
Tray columns are applied in the chemical industry and serve for the thermal separation of multicomponent mixtures. Due to the increasing energy supply from renewable sources a more flexible operation of such apparatuses is required. However, since high separation efficiencies need to be maintained in the associated partial load and overload scenarios, the design process becomes a challenging task. Particularly the design of high performance trays with fixed and/or push valves suffers from missing tools and methods for estimating the influence of the tray design on the complex two-phase flow of liquid and vapor as well as the operation limits.
Therefore, the collaborative iGF-project of HZDR, TU Munich and Ruhr-Universität Bochum aims at closing this gap and extensive experimentation will be conducted in order to characterize the two-phase flow on valve trays in dependence of valve type, valve number, valve arrangement as well as operating conditions and fluid systems. Based on the experimental results models are subsequently developed and will allow for facilitating the design process of high performance trays with fixed and push valves in practice.
The subproject of the Institute of Fluid Dynamics at Helmholtz-Zentrum Dresden-Rossendorf is divided in two parts. In the first part a two-dimensional sensor array is specially designed and constructed for the application in the large-scale facility of TU Munich in order to characterize the two-phase flow on the test trays. The custom-made sensor array allows for measuring a three-dimensional distribution of the temporally averaged phase fractions above the tray as well as the average liquid velocity by additionally using a tracer solution.
In the second part a coarse-grid CFD approach is developed, which enables investigating the influences of valve type, valve number and valve arrangement on the macroscopic flow structures by numerical simulations. The individual valves will be modeled by point-like mass and momentum sources. For validation purposes experiments are carried out with a lab-scale test rig that allows for detailed investigations of single valves and valve groups under pre-defined operating conditions. These investigations will make use of sophisticated in-house measurement techniques in order to gain detailed information on flow fields and patterns. In order to demonstrate the capabilities of the CFD model for simulating the two-phase flow in industrial-scale units, simulations of the TU Munich facility will be compared with related experimental data.
Further details on the project structure and the tasks of our partners are available on the project website: https://www.hzdr.de/coltray
- RVT Process Equipment GmbH
- WelChem GmbH
- BASF SE
- Covestro Deutschland AG
- ENVIMAC Engineering GmbH
- Evonik Technology & Infrastructure GmbH
- Horst Weyer & Partner GmbH
- HZDR Innovation GmbH
- IBE Ingenieurbüro Bulander & Esper GmbH
- Linde GmbH, Linde Engineering
- Raschig GmbH
The project is funded by the Federal Ministry for Economic Affairs and Energy in frame of iGF-grant 20835 BG.
Duration: 01.03.2020 - 28.02.2023
- Vishwakarma, V.; Wiedemann, P.; Schleicher, E.; Schubert, M.; Hampel, U.:
A new approach for estimating the effective froth height on column trays
Chemical Engineering Science 231 (2021) 116304, doi: 10.1016/j.ces.2020.116304