The Vortex-Tube as a Tool in Sustainable Energy Production (10538)

A vortex tube is an apparatus by which compressed gas is separated into cold and warm streams. Vortex tubes can also be used to separate light and heavy components in a gas flow. The vortex tube has a simple construction: a round tube with a tangential inlet opening and two exits on both sides of the tube. Simplicity and no moving parts have made the apparatus popular for applications where compressed air is at disposal to generate cooling. Although the apparatus has been investigated for cooling, there has been little study of its potential for gas component separation. The unique combination of compressible flow, turbulence and local temperature decrease makes the vortex tube of potential interest as a device for treating contaminated gas or for removing other condensable components. In this project we propose to establish whether a modified vortex tube can be used for natural gas separation and production.
The emphasis is on separation processes relevant for the production of sustainable energy. We consider in particular the separation of CO2 from contaminated natural gas resources, syngas production and in flue gases formed in combustion processes.
Combination of experimental and numerical research is needed to probe the applicability of the vortex tube. Experiments will be made with 3-D laser doppler anemometry (LDA), by which the full three-dimensional velocity field including fluctuations, and the separation behavior will be measured. Application of LDA is new in the research on the vortex tube. For the numerical modeling use will be made of large eddy simulation (LES). LES is a very useful method to study complex flows like in vortex tubes, because in this way the different terms of the turbulent kinetic energy equations can be computed. This will give a full insight in the mechanisms that occur in the vortex tube. The equations of motion for the droplets will be added to the LES in order to study and optimize the separation behavior. A subgrid model for the droplet-gas interaction will be constructed based on direct numerical simulation (DNS) of droplet-laden flow in a simpler geometry.
The experimental and numerical results will lead to a design in which the separation properties will be optimal. To this end new concepts will be investigated, like the cooling of the outside of the vortex tube or enhanced solid body gas rotation. With the knowledge obtained in this way, a demonstrator will be built in order to test the separation performance under industrially relevant practical conditions.

Utilization.
There are a large number of patents as well as scientific papers known in which vortex tubes are used as coolers, dryers, condensate separators, or even for isotope separation. As there is no general scientific theory available by which the performance can be predicted, the development is made via the expensive method of trial and error. For Gasunie, Twister, Shell, VortexEng, and RWE, separation and condensate removal is an important process for production of natural gas. The current proposal concerns separation of liquid and gas, in particular separation and removal of water, higher hydrocarbons and liquid CO2 (with a logical extension to H2S) out of natural gas. In this proposal the emphasis lies on experimental research to determine and characterize separation performance of vortex tubes. Apart from experimentally demonstrated separation, also access to results of a computational model that predicts the separation behaviour is of high importance, as this will lead to improved designs of separation apparatus for the industry. In the end phase of this project a prototype will be built and tested in a gas flow installation at the industry.
The enormous problems of increased demands for fossil fuels on the one hand and the shortage on the other hand can partially be solved when natural gas from contaminated wells is cleaned, so that these wells are also economically exploitable. A solution for this is application of the separation technology described in this proposal, by which contaminant condensed gases can be removed from natural gas. Other applications of the technology are upgrading of syngas mixtures, cleaning of gas in the international gas distribution network and the separation of CO2 out of flue gases. When the technology as described here can successfully be applied it will have a gigantic impact. Contaminated gas wells are then exploitable which represents an economic profit of hundreds of millions. Also improved equipment for better gas cleaning will lead to additional turnover for the companies that apply this equipment as well as for the companies that sell it. So we expect that this project will also generate momentum for the further commercialisation and market opportunities in this field. We estimate the recover time for the investments of this project to be short.