Overview

CWS Output

CWS Output

Coal Water Slurry (CWS) is a homogeneous 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 mazut (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 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)

CWS Production&Combustion Scheme

Raw materials for Coal Water Slurry:

  • Coal of most types: brown (lignite), 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.

Coal Water Slurry Benefits

  • CWS is used as a full or partial substitution of gas, oil, or coal in water heating and steam boilers.
  • Heat produced from CWS is cheaper than from Oil, Diesel, Gas
  • Ash after the CWS combustion is an ideal amendment to cement
  • Gas or oil/diesel still could be used as a major or reserve fuel
  • CWS could be produced from the most types of coal: brown, gas, gas-flame and anthracite.
  • UNIQUE from EET: CWS produced from oil coke (petcoke) and pyro-carbon (carbon from tyres) is a perfect low-ash fuel for steam/heat boilers

Coal Water Slurry Production&Combustion – Video

Still have questions about CWS? Read our f.a.q.!

Interested? Contact Us for more information!