Coal Water Slurry / Carbon Slurry Fuel (CWS)

CWS OutputCWS is a mixture of finely milled coal or other carbonaceous materials with water or an aqueous emulsion:

CWS = Coal (58% … 70%) + water emulsion (29% … 40%)

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

CWS Production&Combustion DiagrammCWS production consists of three main parts:

  1. Coal crushing if the original coal size exceeds 12 mm
  2. Wet milling and homogenization in Wet Milling Machine
  3. 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.

CWS Combustion in Pre-chamber

CWS Combustion in Pre-chamber

CWS co-firing in a coal boiler

CWS co-firing in a coal boiler

How It Works - Video!