Wear of geothermal turbine. - Háskólinn í Reykjavík Geothermal Power Plants Andakílsárvirkjun...

Wear of geothermal turbine. Sæmundur Guðlaugsson

ON

Presentation subject

1. ON Power

2. Maintenances plan

3. Main machinery parts of Turbine

4. Main wear problem and planning and development.

5. Conclusion

Reykjavík Energy

Group Reykjavík Energy is owned by three municipalities: The city of

Reykjavik, Akranes and Borgarnes.

ON Power: Production and sales of electricity and hot water.

OR Utilities: Distribution of electricity, hot water, cold water

and runs the sewage systems.

GR Fibernet: Operates a fiber optic network

Power Plants

Hellisheiði Geothermal Power plants

Nesjavellir Geothermal Power Plants

Andakílsárvirkjun Hydro power plant

Capacity of 8 MWe

Hellisheiði Power Plants 2006

Combined Heat and Power plant

303 MWe of electricity and133 MWth of thermal

Nesjavellir Power Plant 1990

Combined Heat and Power plant

Commissioned : 2005 (newest

part)

120 MWe of electricity and 300 MWth of thermal

ON Power

36 boreholes for Hellisheiði Power Plants 19 boreholes for Nesjavellir Power Plants Nesjavellir 240 kg/s Hellisheiði 480 kg/s

Maintenances plan

» After two years of running, turbines is stop in one week for inspection,

electrical inspections along with views of auxiliary equipment and cleaning

of the cooling tower

» After four years of running, turbines is stop in three weeks for overhauling

» After twelve years overhauling of the generators

Overhaul of geothermal turbine

» Replacement of defective parts

» Cleaning parts

»Repair worn parts

» NDT inspection of rotors

» Settings of diaphragm

» Measurement of seals

»Assemble

Machinery parts of Turbine

Main wear problem planning and development

Dissolution of seats for the diaphragm

The stem and woter is flow under the diaphragm an is cut the set and the diaphragm

Repair the wear of seats for the diaphragm

Milling for the 304 strip

strips fixed by welding

The seat in the casing is grinding

down of 2mm and welded with 309

Mo wire

Dissolution between blades on the diaphragm

The steam has

excavated down into material

Dissolution between blades on the diaphragm

•The steam has engraved into

the material

•Welding wire ER309Mo or D-10 Ni base 182 Nickel Base Alloys.

Welding near the blade

Special holder for diaphragm designed for welding

CMT welding for the diaphragm

» CMT stands for Cold Metal Transfer

» Reduced heat exposure to the material that is being welding

» Reduced mixing of the base material in the welding string

» The risk of deformation will be lower

Before repair Surface welded with stainless wire ER309Mo After 2mm metal processing Final metal working

After repair 2mm stainless coating on surface assembly.

Repair of dissolution in assembly surfaces

Dissolution in the casing bottom

Improvements of drain water from engine

Condensate water

drains directly from

steps and drains

increased.

Dissolution of the rotor

Dissolution of the balance hole and connection point

for the blade.

Dissolution of the last blade

Turbine axle worn.

Our method now:

Mille down 5mm

and welde with

Inconel wire..

heat treatment

Repair of turbine blades

Wear gap in blade

Material in the blade

AISI 630

Rotor workshop in Hellisheiði Power Plants

Invested in:

Balance unit

Lathe

Welding unit

PWHT equipment

NDT equipment

Rotor repair example

Repair and provides components in geothermal

turbines ON

Conclusion

» Lower spare parts prices

» Lower the cost of repair of turbine components

» High quality work on repairs based on what was known from foreign

suppliers.

» Raises the level of technology in the country

» increases operational reliability

» Creates jobs in the country

» We estimate when wee have used this repair technology for all of our units

it will be possibility extended between the overhauling from four years to

five or six years.

Conclusion

» Lower spare parts prices

» Lower the cost of repair of turbine components

» High quality work on repairs based on what was known from foreign

suppliers.

» Increase the knowledge of repair techniques in the country

» Increases operational reliability

» Creates jobs in the country

» Saves currency

» Because of this repair development it will be possible to extend between

owerholing of units from four years 5 to 6 years when we have finished a

overhaul of our machines with this techniques.

Foresight-Efficiency-Integrity

Thank you