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Development of torsional grain structures to improve biaxial creep performance of fe-based ods alloy tubing for biomass power plant

Objective



Objectives and content
There is strong commitment in Europe (particularly Sweden
and Denmark) to renewable. particularly biomass, energy
generation. Technologies and means for developing
biomass plant with higher energy conversion efficiencies
are, therefore. essential. Advanced, indirect Combined
Cycle Gas Turbine (CCGT) systems offer overall biomass
energy conversion efficiencies of 45% and above, compared
with the 35% efficiency of conventional biomass steam
plant. However to attain this efficiency in CCGT
operation it will be necessary to develop a heat
exchanger capable of gas operating temperatures and
pressures of around 1100 C and 15-30 bar, respectively,
for entry heating the gas turbine working fluid. This
requires heat exchanger tubing capable of sustained
pressurised service at temperatures of 1100 C and above:
none currently exists. The industrial objective of the
project is to use highly innovative materials processing
methods to sufficiently enhance the creep performance of
existing Fe-based ODS alloy tubes to demonstrate the
practicability of a high temperature biomass heat
exchanger. Processing developments will be supported by:
laboratory and plant creep tests; tube joining studies;
improvements to alloy oxidation resistance;
interpretation and modelling; and plant feasibility
studies.
Specific industrial and technical objectives of the
project will include:
forming of Fe-based ODS alloy tubing with a highly
innovative and radically reorganized grain structure
significantly more favourably disposed to survive high
temperature biaxial creep
data establishing enhanced creep performance of the
tubing (lOOOh creep data at up to 1150 C, augmented by
laboratory and biomass plant pressurised tube creep tests
to 100h at 1150 C)
development and validation of solid state joining
techniques for the tube (S/R to 10000h/1150 C)
biomass/air oxidation studies as a precursor to a post
project functionally graded "ideal" ODS alloy
clarification and quantification of key secondary
factors (powder processing /microstructural) limiting
creep performance; defining other processing constraints
to improve ODS alloy creep life.
develop models of ODS alloy creep and recrystallisation
behaviour to guide processing control
establish key feasibility and design issues for a
biomass plant which is to operate with a high temperature
heat exchanger; begin a networking initiative as a
precursor to exploitation.
The approach to reach the objectives will involve a
project with two overlapping stages spread over 3 years:
During stage I, proof of concept for grain manipulation
will be established and enhanced creep performance
endorsed by benchmark tests. Tube joining and testing
will commence. A plant feasibility study will be
initiated. Microstructural interpretation and modelling
will be used to support processing developments.
During stage II, long term biaxial creep (pressurised
tube) data will be generated in the laboratory and in a
biomass plant for stage I alloys with optimal grain
structures. Tube joints will be subject to long term
stress rupture tests. Alloys with controlled powder
defects will be produced and tested to identify and rank
secondary factors influencing creep life. Alloy Y203
level optimum for oxidation resistance will be explored
and tested in air and biomass plant environments. The
feasibility study will be extended and a technology watch
activity initiated. The latter will: bring focus to
commercial end user exploitation issues; and disseminate
agreed information to stimulate interest. Fully
predictive models of creep and recrystallisation
behaviour will be developed and applied to project data.
The implication of the work for Ni-base ODS alloys will
be explored. Industrial scale production processes and
methods will be used throughout the project to reduce
unintended variability and substantially reduce time to
market during the exploitation phase.
The consortium of partners assembled to carry out the
project is freshly constituted and brings together
organizations from four European member states. The team
includes: a world class advanced materials supplier; a
company expert in flow forming; a leading international
fabricator of power generation plant; and a highly
committed biomass end-user. The R&D performers in the
project contribute the full cross section of
complementary materials science skills and resources
necessary to support the project; many of these skills
are world class.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Metallwerk Plansee GmbH
Address
23,Siebenbürgerstraùe
86983 Lechbruck
Germany

Participants (6)

MITSUI BABCOCK ENERGY LTD*
United Kingdom
Address
Porterfield Road
PA4 8DJ Renfrew
Metall-Spezialrohr GmbH
Germany
Address
400,Hagener Strasse 400
58239 Schwerte
RISOE NATIONAL LABORATORY
Denmark
Address
Frederiksborgvej 399
Roskilde
Sydkraft Konsult AB
Sweden
Address
1,Carl Gustafs Väg 1
205 09 Malmö
THE UNIVERSITY OF LIVERPOOL
United Kingdom
Address
Brownlow Hill
L69 3GH Liverpool
University of Cambridge
United Kingdom
Address
Pembroke Street
CB2 3QZ Cambridge