| Title | Pressure Retention Valve for Subsurface Applications |
|---|---|
| Authors | Weimann, T; Zeilinger, W; Kariman, M; Ruff, M |
| Year | 2016 |
| Conference | European Geothermal Congress |
| Keywords | geothermal energy, binary cycle, pressure retention, scaling, subsurface application, downhole valve, valve, cavitation prevention |
| Abstract | gec-co Global Engineering & Consulting-Company GmbH and the iPAT (Institute of Process Machinery and System Engineering) at the FAU University Nürnberg-Erlangen develop a pressure retention valve for geothermal downhole application. The target of the invention is to avoid and/or to decrease the scaling and degassing of the geothermal fluid. In advanced binary geothermal power plants the pressure at the re-injection well drops due to low counter pressure of the reservoir. In this case dissolved substances, e.g. solids or gases start to deposit or degas. Then chemical reactions start and the possibility of scaling initiates. Therefore, in most geothermal power plants it is recommended to have a pressure retention installed. State of the art is to install the pressure retention at surface. This has the consequence, that the following pipes, controls and instruments are not protected from scaling caused by depositing or degassing. The conclusion of this experience is that the whole piping and instrumentation has to be protected and the pressure retention should be installed down hole, especially underneath the static water level, to expose the fluid at the outlet to a certain pressure that keeps the fluid from depositing or degassing. A further critical issue for pressure retention at high pressure and flow levels is cavitation. The invented geometrical feature deals with this problem and guarantees a certain flow speed at the overall length of the valve system. This will avoid partial low-pressure and even protects the valve material from the negative effects of cavitation. |