Coal Water Slurry / Carbon Slurry Fuel (CWS)
CWS has almost the same viscosity as masut (heavy fuel oil) what makes it suitable both for pumping on short and long distances and for spraying into a boiler via specially designed nozzles.
Gas, oil/diesel, coal still could be used as a redundant fuel for boilers.
Coal Water Slurry Production
- Coal crushing if the original coal size exceeds 12 mm
- Wet milling and homogenization in Wet Milling Machine
- Intermediate Storage of CWS (use and/or sale of CWS)
Raw materials for Coal Water Slurry:
- Coal of most types: brown (lignithe), gas-flame, anthracite
- Carbonaceous Raw Materials: pyrocarbon (carbon after pyrolysis of tires, rubber), petroleum coke, etc.
- Desired raw material ash content – up to 15 … 16%
Coal Water Slurry Combustion
CWS is sprayed into a boiler through EET’s pneumo-nozzle which is specially designed to spray slurry fuel.
There are three major methods for CWS combustion:
- Independent combustion in a swirl pre-chamber, which is installed in a front of boiler
- Co-firing together with existing fuel – coal, diesel/oil (HFO), gas
- Independent combustion with spraying CWS by oxygen (O2)
Combustion in swirl pre-chamber allows to burn CWS autonomously, diesel/gas required only for initial preheating.
Co-firing gives a flexibility for boiler owners to choose between fuels. Typical CWS/fuel ration is 80%/20%.
CWS can be burned in most of steam and hot water boilers. Existing boilers in most cases are upgradable by installing prechamber or simply CWS-nozzle.
Existing oil/gas boilers require installation of ash collection system or installation of pre-chamber.
CWS combustion method depends on boiler type, locally available raw materials, and other factors.