10502025 Steam Boiler Power Plant with 240 MWth Pyroflow Biomass CFB
Boiler
Sustainable, Low-Emission Biomass CHP Power Plant with Proven
Operational Excellence
High-performance combined heat and power (CHP) plant with an electric
capacity of 88 MVA and a thermal capacity of 240 MW. The plant is
engineered for efficient and environmentally responsible operation
using wood-based biomass as its primary fuel, with coal used only as a
secondary support fuel under extreme moisture conditions. The plant
remains in full operational service and includes all systems from
biomass fuel feeding to electricity and steam dispatch. It has been
exceptionally well maintained, consistently upgraded, and meets or
exceeds today’s strictest environmental and quality requirements.
The steam boiler employs Circulating Fluidized Bed (CFB) combustion
technology, commercial type PYROFLOW, manufactured in Finland by
Ahlström in 1989. This technology ensures high-efficiency,
low-emission combustion of a wide range of solid fuels—even with
high variability in moisture and calorific content—making it ideal
for modern, carbon-conscious operations. The CFB boiler operates with
a steam flow of 100 kg/s, at 137 bar pressure and 535°C temperature.
The primary fuel is wood-based biomass with a moisture content of
35–55%, ensuring carbon-neutral energy production. Coal has been
used choiceively during wet conditions to improve combustion
balance.
The fluidized bed consists of quartz sand, with optional limestone
injection for SOx control during coal operation. Emission performance
remains excellent, with NOx and SOx levels well below regulatory
thresholds. The boiler tubing is inspected annually, and all
auxiliaries receive comprehensive servicing during scheduled
maintenance outages.
The steam turbine plant is supplied by Siemens, comprising a
extraction back-pressure turbine with an integrated district heating
section, a condensing turbine, and an 88 MVA / 10.5 kV / 50Hz
generator with auxiliaries. The 3.5 bar extraction steam is delivered
to nearby industry and used to produce hot water for district heating,
enabling a high-efficiency cogeneration process that minimizes energy
waste and maximizes environmental value. In condensing mode, the
turbine operates at full electricity output, with remaining
low-pressure steam condensed efficiently in a tubular condenser.
Both turbines were refurbished to factory zero-hour” condition by
Siemens Germany in 2023. The alternator was also inspected and
confirmed in excellent condition. All major maintenance and life
extension work—including a comprehensive lifespan evaluation by
Sumitomo in 2022—confirms over 10 years of reliable future
operation.
The plant’s automation and control system was fully modernized in
2016 and now operates on Siemens T-3000 platform with Simatic S7 PLCs,
enabling reliable, around-the-clock operation with automated
supervision. The operators also manage a separate 120 MW auxiliary
steam boiler from the same control room. Each plant features its own
independent power status, boiler protection, and automation
infrastructure (I/O level, processor stations, and HMI), allowing
parallel or independent operation. The plant’s flexible design and
digital control system contribute to enhanced operational
sustainability and energy efficiency.
Technical Characteristics – Steam Boiler Plant
Manufacturer: Ahlström (Foster Wheeler / Andritz)
Boiler Type: Circulating Fluidised Bed – PYROFLOW
Thermal Capacity: 240 MW
Steam Output: 100 kg/s, 137 bar, 535ºC
Year of Manufacture: 1989
Fuel: Wood-based biomass, peat, coal
Technical Characteristics – Turbine Plant
Back-Pressure Steam Turbine: Siemens Extraction EHNKS 90/80-4 with
district heating section
Live Steam Input (Back-Pressure): Max. 84 kg/s at 137 bar, 535ºC
Live Steam Input with DH Section: Max. 100 kg/s
Year of Manufacture: 1989
Condensing Turbine: Siemens WK 63/81/32-3
Live Steam Input (Condensing Turbine): 30 kg/s at 3.5 bar
Rotational Speed: 3,000 rpm
Generator: Siemens 88,000 kVA / 50 Hz
Voltage: 10,500 V