| Title | Geothermal steam for glycol plant |
|---|---|
| Authors | Gunnlaugur Fri?bjarnarson, Teitur Gunnarsson and Gunnar Herbertsson |
| Year | 2003 |
| Conference | Iceland Geothermal Conference |
| Keywords | geothermal steam, chemical process, glycols, sugar, molecularcontribution, UNIFAC modelling. |
| Abstract | Chemical processing includes in wide terms the application of chemical reactions, mass and heat transfer. Traditional obstacle to utilisation of geothermal steam for chemical processes has been the limited steam temperatures and pressures available from the geothermal fluid separators. In a prefeasibility study of a plant for manufacturing ofvarious glycols from sugars the viability in using geothermal steam for all main heating and separation tasks has been estimated. A model calculation based on chemical functional group contribution methods shows better separation behaviour at lower pressure and temperatures. This enables the use of medium pressure steam (10-15 bar)for 95% of all thermal tasks. Only a minor part of the process tasks requires higher temperature where the heating media has to be 250թ՞300?C. This temperature can be obtained from a conventional high-pressure boiler system. Process optimisation and systematic re-utilisation of heat has reduced the steam consumption and enhanced the overall economy. Approximately 50 MWth of geothermal steam is needed to produce120.000 tpa glycols and alcohols and the low steam pressure required gives more options in locating the glycol plant. Fundamental problem in locating such a plant remains to find a steam source close to a harbour for ocean going vessels to minimize inland transport cost. |