Comparative analysis of alternative means for removing noncondensable gases from flashed-steam geothermal power plants

Vorum, M. ; Fitzler, E.

National Renewable Energy Laboratory (U.S.)

关键词: Flashed Steam Systems;    Natural Steam;    Economics;    Geothermal Legacy;    Geothermal;   

DOI  :  10.2172/758765
RP-ID  :  NREL/SR-550-28329
RP-ID  :  AC36-99GO10337
RP-ID  :  758765

美国|英语

来源: UNT Digital Library

【 摘 要 】

This is a final report on a screening study to compare six methods of removing noncondensable gases from direct-use geothermal steam power plants. This report defines the study methodologies and compares the performance and economics of selected gas-removal systems. Recommendations are presented for follow-up investigations and implementation of some of the technologies discussed. The specific gas-removal methods include five vacuum system configurations using the conventional approach of evacuating gas/vapor mixtures from the power plant condenser system and a system for physical separation of steam and gases upstream of the power turbine. The study focused on flashed-steam applications, but the results apply equally well to flashed-steam and dry-steam geothermal power plant configurations. Two gas-removal options appear to offer profitable economic potential. The hybrid vacuum system configurations and the reboiler process yield positive net present value results over wide-ranging gas concentrations. The hybrid options look favorable for both low-temperature and high-temperature resource applications. The reboiler looks profitable for low-temperature resource applications for gas levels above about 20,000 parts per million by volume. A vacuum system configuration using a three-stage turbocompressor battery may be profitable for low-temperature resources, but results show that the hybrid system is more profitable. The biphase eductor alternative cannot be recommended for commercialization at this time.