TURBINE BYPASS VALVE- TRUE COST INVESTIGATION
Speeches include:
Operational Flexibility of Gas Turbine Power
Plants
HRSG and SCR Performance Optimization
Stands include:
AECOM,
Adams
Valve,
A-T
Controls,
Black
& Veatch,
Bray,
Burns
& McDonnell,
Clarke,
Co-Ax,
Conval,
Doosan,
Emerson,
JASC,
SPX,
Wood.
Two background documents have now been added:
Turbine Bypass Valve Suppliers
http://www.mcilvainecompany.com/PowerGen_2019/Turbine_Bypass_Valve_Suppliers_10-31-19.pdf
Turbine Bypass Technology and
Applications
Issues to be discussed:
Noise
Plug valve sticking
Leakage
Optimal bypass % range
Reaction time
Materials for LP vs. HP vs. new conditions, such
as cycling or ultrasupercritical conditions
Multi-stage pressure reduction to reduce trim
wear
Stellite delamination
Flow accelerated corrosion
Maximizing power output
More on Turbine Bypass Valves--We
talked to Ory Selzer, manager of application
engineering at IMI -CCI. He will
not be able to attend the show but did offer
some thoughts. We have highlighted decisive
factors and issues in red.
“Turbine Bypass Systems are a critical part of
every Combined Cycle Power Plant (CCPP). In
today’s markets, CCPPs must
be flexible, reliable, agile and available. Turbine
Bypass Systems are integral to plant startup and
plant protection and as such they are one of the
most important valve systems in a CCPP.
Some 15 years ago, North American CCPPs began
seeing cracking downstream of Turbine Bypass
Systems, in the high thermal stress regions
where water is injected into the steam to cool
it down. What was first met with surprise and
shock—a cracked steam pipe—has now become almost
a norm at CCPPs. Much is known about how these
cracks occur, and IMI CCI has been helping
customers reduce, repair and eliminate these
cracks by upgrading designs for cycling
operation. Ten years ago, even 5 years ago, I
would have said that cracking in Turbine Bypass
Systems was one of the biggest concerns any CCPP
End User/Owner should be worried about at their
plant. Today cracking
still remains a major concern,
but we are learning
that one of its root causes is even more
concerning—wet steam erosion.
In a market where startup times are critical and
every minute counts, CCPPs are trying to get up
to speed (load) as fast as possible, at any
cost. One consequence of this need for speed not
allowing steam lines to warm up. Inadequate
drain designs, improper vent valve sizing, or
simply operational protocols lead to the
collection of condensation in steam lines during
startup.
Condensation production is swept along with the
first flows of steam, and in many plants the
first place this steam goes is through the HP
Turbine Bypass System (in order to get flow to
the reheater as quickly as possible to avoid
overheating). Water mixed with steam at even
modest velocities will cut through almost any
metal, including Inconel 718 and stellite 6, two
of the stronger materials used in Turbine Bypass
valve trims. Erosion leads to leakage, leakage
leads to overheating of downstream piping or
condensers calling in the desuperheater to
spray, thus leading to thermal stress. Do this
dozens of time a day and after one year you get
the cracking that has plagued the industry for
more than a decade.
Wet steam erosion is a major player in this
cracking epidemic. IMI CCI has seen wet steam in
numerous CCPPs throughout the world. We
understand the need for speed, but we also know
the limits of material science and physics. We
can help the CCPP End User / Owner /
Operator understand, evaluate and ultimately
eliminate this problem and
avoid the painful cost of repairing cracks,
replacing hardware, and forced outages.”
You can contact Ory Selzer, Manager Application
Engineering, IMI CCI. At 949-835-8210 or ory.selzer@imi-critical.com
Relative to IMI activities, the company is very
active in combined cycle plants in the U.S. It
is also active around the world.
In 2015 IMI CCI® Sri City successfully
manufactured its first turbine bypass valves for
a 1050 MW supercritical power plant, after the
Sri City manufacturing facility successfully
passed an audit by the commissioning company.
The valves were the first produced in India for
a 1050 MW thermal power project.
The Japanese engineering, procurement and
construction company (EPC) for the project chose
IMI CCI® Japan to supply eight sets
of low-pressure turbine bypass isolation and
control valves, each with a capacity of 1050 MW.
While the assembly and testing of the turbine
bypass valves was undertaken at IMI CCI® Japan,
IMI CCI® Sri City was chosen as the
manufacturing facility for the valve body
(including all welding and desuperheater), fully
machined internals and the bonnet.
Both IMI CCI® Japan and IMI CCI® Sri
City collaborated closely during the
manufacturing cycle to ensure the project was
completed and shipped on time, to meet the
customer's specification.
Background Data in
Coal
Fired Boiler Decisions (Free To Power
Plants)
Emerson Actuator replacement solves turbine
bypass problem
As often as four times a year during winter
months, a power plant in Wisconsin would miss a
scheduled start of its combined cycle power
plant due to malfunctions of the turbine bypass
valves. This article describes how the problems
were solved by replacing the actuation
components on those valves. Revision
Date: 10/17/2019
Vector and Wellheads engineering turbine bypass
system
This paper has a good flow diagram with valve
locations. The turbine bypass system is a very
important component in power stations, and of a
difficult service too. Revision Date:
9/9/2019
Proper Steam Bypass System Design Avoids Steam
Turbine Overheating
The steam bypass system is generally used during
the following modes of operation: start-up and
shutdown, steam turbine trip, steam turbine
no-load or low-load operation, and simple-cycle
operation. On start-up, the isolation of the
CTG/HRSG from the STG allows the CTG to be
placed on load without delay and well before the
heat-up and roll-off of the STG. In addition, a
faster start-up of the STG is possible since the
bypass system provides the capability of close
temperature matching between the steam inlet
temperature and the steam turbine metal
temperature.
BHGE expands ASME Section I portfolio to include
liquid Economizer and Thermal Fluid Heater
Valves
BHGE announces the expansion of the Consolidated
ASME Section I portfolio, to now include 1900
LA1 spring-loaded and 2900 LA1 pilot-operated
B&PV code approved liquid safety relief valves
as solutions for liquid over-pressure protection
for Economizers and thermal fluid heaters.Revision
Date: 8/15/2019
BHGE and DARVICO together supply Control Valve
Package to World’s Largest IGCC Power Plant
BHGE announces the delivery of the highly
engineered, severe service control valve
packages to Saudi Aramco’s Jazan Integrated Gas
Combined Cycle Power Plant.
Revision Date:
8/15/2019
Valve stem seal selection criteria
For ultra-supercritcal service graphite packing
without PTFE and binders is proven to be a low
total cost of ownership option. Seals can also
be protected by an oxygen inhibitor and be live
loaded for protection against thermal cycling
Valve stem seal selection criteria, Flow
Control, Mar 2017 Revision Date:
8/12/2019
Larsen & Toubro has complete range of valves for
ultra-supercritical coal plant
The Indian market accounts for nearly 50% of L&T
Valves revenue, and the balance comes from
international markets, with the Middle East
being the most prominent territory. “We are a
one-stop-shop for almost all types of process
valves – gate, globe, check, ball, butterfly,
and plug valves. We offer these valves in many
combinations of size, pressure class, materials,
and so on, and we are equipped to provide our
clients with almost all their process valves
requirements” says N.V. Venkatasubramanian (Venkat),
Chief Executive and Director. “Further, L&T
Valves also offers a complete range of valves
for the power industry. In fact, we are one of
the few companies that can offer all valves and
accessories required for an ultra-supercritical
thermal power station.” “Custom-engineered
solutions for defence and aerospace applications
form an important part of our portfolio. The
experience that we gain from working in these
sectors has helped us to improve our product
quality, strengthen our processes and expand our
knowledge base.” Revision Date:
8/12/2019
