Waste-to-Energy Retrofit: Centrifugal Fans for CFB Boiler-to-Grate Furnace Conversion
A waste-to-energy plant recently completed a major combustion system retrofit, converting its existing circulating fluidized bed (CFB) boiler to a mechanical grate furnace.
This type of furnace conversion changes more than the combustion equipment itself. The new furnace configuration brings different requirements for combustion air, air distribution, furnace cooling, sealing and flue gas extraction.
As a result, the original fan system needed to be re-evaluated against the new operating conditions. The existing fans could no longer be directly matched to the updated process parameters.
New Fan Requirements After the Retrofit
Based on the revised operating conditions, SIMO BLOWER supplied 10 centrifugal fans for five different process duties:
- Primary air fans — supplying combustion air to the furnace
- Secondary air fans — supporting combustion and air distribution
- Furnace wall cooling fans — providing cooling air for furnace components
- Sealing air fans — supplying air for sealing applications
- Induced draft fans — extracting hot flue gas from the system
The supplied fans cover a wide operating range:
Airflow: 4,510–234,400 m³/h
Pressure: 2,760–8,500 Pa
Temperature: 30–150°C
The induced draft fans, for example, are designed to handle hot flue gas at approximately 150°C, with airflow requirements reaching 234,400 m³/h.
Why Fan Replacement Was Necessary
When a waste incineration system changes from a CFB boiler to a mechanical grate furnace, the operating point of the air and flue gas system may also change.
The required fan performance needs to be reassessed according to the new:
Airflow · Pressure · Temperature · System Resistance · Process Duty
Simply selecting the same fan model as the original system does not guarantee that it will meet the requirements of the upgraded process.
For this project, SIMO selected the replacement fans according to the new process parameters, rather than simply matching the previous equipment.
Matching the Fan to the New Process
Different fans perform different functions within a waste-to-energy system.
The primary and secondary air fans support the combustion process, while cooling and sealing fans serve specific equipment protection and sealing requirements. The induced draft fans handle the hot flue gas and maintain the required gas flow through the system.
This means that even within the same waste-to-energy plant, fan selection must be based on the specific duty of each process point.
SIMO BLOWER for Waste-to-Energy Fan Retrofit
For waste incineration and waste-to-energy retrofit projects, SIMO BLOWER provides centrifugal fan solutions based on the updated process requirements.
Our engineering approach covers fan selection according to airflow, pressure, temperature, gas conditions and installation requirements.
Changing the process may change the fan requirements.
If you are planning a waste-to-energy retrofit, boiler conversion or centrifugal fan replacement, provide your updated operating parameters and existing fan information.
SIMO engineers can help evaluate the appropriate fan solution for the new process.
