SOLUTIONS FOR GEOTHERMAL POWER PLANTS

Transcription

1 SOLUTIONS FOR GEOTHERMAL POWER PLANTS

2 Ansaldo Energia and Geothermal Energy Geothermal energy is a valuable, renewable natural energy comparable to hydroelectric energy and it is environment-friendly because it generates electric power without burning fossil fuel. Ansaldo Energia, a Finmeccanica company, banking on more than one century of experience in power generation, with a total installed capacity of over 175,000 MW, is a distinguished player in the energy industry, providing reliable and flexible solutions in the power generation sector across a complete and innovative products portfolio including equipment and plant designs, engineering, manufacturing, contracting, service activities and customers assistance for thermal, geothermal, combined cycle and many activities for nuclear power plants. Ansaldo Energia s experience with geothermal power plants dates back to 1913, when the first turbine-generator unit ever driven by geothermal steam rated 250 kw, entered service at Larderello (Italy). Since then units totalling over 2,000 MW have been installed both in Italy and abroad.

3 Geothermal Steam Cycles Geothermal fluid may be in the form of steam or hot water, or a combination of the two: geothermal fields are named accordingly as vapour dominated or liquid dominated, with single, or double flash system and their exploitation for power generation involves different plant arrangements to feed steam into the turbines. 55 MW Steam Turbine Steam Steam Ejector Demister G Steam Turbine To Atmosphere Cooling Tower Air Condenser Steam & Brine From Wells To Injection Wells Typical Single-Flash Geothermal Power Plant

4 Equipment for Geothermal Power Plants Ansaldo Energia can provide optimized solutions for geothermal power plants in the range 20 to 150 MW for 50 and 60 Hz markets. Plant design, supply and installation Ansaldo Energia can provide not only steam turbine - generator sets, but also complete integrated package including architecture, civil, mechanical, electrical and automation design, supply of equipment, installation and commissioning of the power plant. Steam Turbine Ansaldo Energia is one of the world leading suppliers of geothermal turbines/generators. The Company s extensive experience (more than 130 geothermal units installed) has enabled Ansaldo Energia to achieve a high level of reliability and efficiency as well as remarkable flexibility in terms of adapting to different steam conditions and plant arrangements. State-of-the art technology, and cutting edge construction methods are used to provide different turbine models for different geothermal steam conditions and power output levels and to 20 MW - Shop assembly upgrade old units to match changed steam conditions. Careful material selection, due to the presence in the fluid of corrosive chemicals such as H 2 S, chlorides and salts, is extremely important to ensure reliability and minimize outages for maintenance. Ansaldo Energia has carried out detailed studies to test the corrosion resistance of various turbine materials to geothermal steam. All turbine components in contact with the fluid are made of stainless steel, including the rotor when required by the fluid characteristics.

5 Geothermal steam turbine configurations: MW Single Flow MW Double Flow MW Four Flow Geothermal steam turbine design features: Drain catcher applied to each stage Features Benefits Moisture removal groove on moving blades Stellite laser cladding on leading edge of L-0 & L-1 (if necessary) Impulse construction, with new generation airfoil and sealing High efficiency and better protection against foreign materials on steam path Single, double, four flow configuration Compact design with well proven 20, 23, 26, 31 LSB Top, lateral, axial exhaust in addition to conventional down exhaust Simple, low profile arrangement Patented design solutions to prevent problems arising from dissolved solids Moisture protection Simplified maintenance Higher efficiency and better protection against blade erosion Hollow nozzle with slots on suction side to remove moisture Moisture Protection

6 Generator Air cooled generator in closed circuit (TEWAC), featuring a modular, compact design and high efficiency: Rated output: depends on the size Class F insulation system Power factor 0.8 Rated voltage 11.5 or 13.8 kv Static excitation Specific features are introduces for geothermal application to protect the copper from H 2 S corrosion (special painting, gold plating, tinning, etc.). Condenser Since the condensate does not have to be recovered, a spray type direct contact condenser is often used. The condenser is arranged beneath the turbine or laterally connected by means of a crossover steam duct. The water is injected into the condensing chamber by means of a network system consisting of manifolds, pipes and spray nozzles. The condensing chamber is connected to two gas cooler sections where the final condensation takes place, in addition to non condensable gases temperature abatement by means of the spray nozzles on the top and trays arranged beneath the nozzles. The nozzles of the whirl-jet type are with ample orifice section to prevent clogging and are easily removable for inspection and cleaning. The Condenser shell and internals are in stainless steel. Non condensable gas removal system Since the geothermal steam flowing into the condenser contains a large amount of non condensable gas, essentially carbon dioxide (CO 2 ), a high efficiency extraction system shall be provided. Two options are available: Steam ejectors Centrifugal compressor driven by an electric motor or coupled to the turbo-generator. The choice between the two is based on the gas percentage in the geothermal steam: steam ejectors are preferred for low gas content. 3 x 55 MW - Gunung Salak (Indonesia)

7 Control System The control system, based on proven architecture developed by Ansaldo Energia, with reliable hardware, software and system interfaces delivers information to operators and decision makers in an easy usable format and handles operation, maintenance, control efficiency and safety in such a way as to minimize outages. Control system development is based on functional segregation between: Balance of Plant Steam Turbine Auxiliary control loop and slow control loop Steam Turbine Governor Protection System The control system includes the supervisory system which provides the information needed to assess the mechanical condition of rotating machinery. These systems continuously measure and monitor a variety of supervisory parameters, providing crucial information for early identification of machinery problems. 20 MW - Rancia 1-2 (Italy) Services Ansaldo Energia, with its long standing experience in the geothermal power plant sector can provide a wide range of services for both OEM and NON-OEM geothermal plants: New turbines and generators tailor made for old geothermal plants Steam path upgrading for existing units to match changed steam conditions Repairing damaged equipment Supplying replacement parts Generator rewinding Control system 40 MW - 20 MW Nuova Radicondoli and Radicondoli 2 (Italy)

8 Ansaldo Energia Geothermal Steam Turbine References in the World Stampa: Microart Recco - Genova 05/2012 Petergraf MEXICO Los Humeros/Los Azufres 10 x 5 MW Pathe 1 x 2 MW USA Middle Town 2 x 55 MW ITALY > 110 Units > 1600 MW TURKEY Kizildere 1 x 18 MW NICARAGUA Momotombo 2 x 35 MW COSTARICA Miravalles 1 x 55 MW PHILIPPINES Bacon Manito 2 x 55 MW INDONESIA Gunung Salak 3 x 55 MW Dieng 1 x 60 MW Genova - Via N. Lorenzi, 8 - Italy Tel: Fax: ansaldoenergia@aen.ansaldo.it ansaldoenergia.com