Where is the water in CWS come from? Why adding water or water emulsion?
TYpical CWS moisture is about 40%. Internal moisture of most of the coals is 15…30%, accordingly, the amount of added moisture does not exceed 25%. According to the feasibility studies made by EET, the addition of 15 … 20% water and its evaporation in the boiler furnace is more efficient than pre-drying and further milling.
Usage of organic and oil-based water emulsions improves CWS calorific value.
Why CWS is more effective than regular coal combustion?
Coal Water Slurry typically has particles with maximum size 100…120mkm. Burnout level of such particles is much higher comparing to burnout of several centimeters coal lumps.
Thanks to liquid form CWS is pumped by screw pumps what solves the question of metered feeding of coal into a boiler increasing the level of automation.
exhaust gas temperature after CWS combustion is in the range of 120…160C what is lower than with typical coal combustion. This is another reason why CWS combustion is more effective that direct coal combustion.
Additionally, coal dust in a form of CWS is explosionproof.
Why CWS is friendly for environment?
Higher burnout level means lower content of unburnt coal as a waste. Solid ash after CWS combustion is useful for as an additive for cement.
CWS flame (torch) has an average temperature about 800…950C what means lower NOx emissions. According to measurements which are made by Amalthea typical NOx emissions level is always below 100mg/m3, 30…35% less comparing to diesel and coal.
Co-firing of CWS together with coal in standard layer bed improves combustion efficiency.
Why CWS is cheaper than oil, gas?
It is very simple – coal is the cheapest from existing fossil fuels. 1 MJ of energy produced from coal is 2..3 types cheaper than from oil or gas for most markets!
Which temperature is required for CWS storage?
CWS has a water in its content. So, desired storage temperature must be above zero.
Recommended temperature is 10…30C.
How long CWS is stable? Does it make sense to increase storage time?
First question – do you really need a long-term storage?
Storage time for CWS depends on coal/carbon type. We have an experience of long-term storage, about several months, for CWS produced from pyrocarbon (“black carbon” – wastes after auto-tire pyrolysis). Several coal types are stored no longer than couple-three days – CWS started to separate after this time.
Our effective Wet Milling Machine can produce CWS quickly. So, we strongly recommend to produce day or shift amount of CWS, no more. If you still need longer storage time we recommend to use our Feeding complex which is equipped with tank with mixer – CWS will be periodically mixed and/or circulating using a pump.
In worst and last case you can use additives which also can keep CWS stable for a long time.