What is the relationship between graywater quality and coal slurry particle size distribution?
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Recently, the ammonia nitrogen and hardness levels in the gray water have been higher during the day shift and lower during the night shift. I’m wondering if this is related to the fact that around 100 tons of coal ash is used per night shift – the coal particles in this ash are relatively large, so their size remains high even after passing through the grinder. I’d like to hear everyone’s opinions on this
Personally, I think the water quality of gray water has little to do with the particle size of coal powder. Main reasons: 1. If you are using a roller-type coal grinder, the particle size of the coal powder does not change as the quality of the coal changes, because the desired size of the coal powder particles is predetermined in advance. Larger particles of coal powder are sent back to the grinder for further grinding, while those that are too large are discharged from the grinder along with the coal waste; therefore, there is no variation in particle size. 2. Even if there are changes in the size of the coal powder particles, the impact is minimal. The ash produced by the gasification furnace consists of larger particles that are considered slag, while smaller particles are considered ash. When the coal powder particles are relatively larger, more slag is produced; as a result, the ash content in the ash water is relatively lower. So how can ammonia nitrogen and hardness levels increase? Moreover, ammonia nitrogen refers to the nitrogen present in wastewater in the form of free ammonia (NH3) and ammonium ions (NH4+), while total hardness denotes the concentration of calcium and magnesium ions in wastewater; these parameters remain unchanged as long as the type of coal does not change. So, in my opinion, it’s still a matter of operation: high ammonia nitrogen levels may be due to the addition of N2, while high total hardness might result from insufficient addition of alkaline solution, which causes the pH to drop.
I also think that the quality of gray water has little to do with the normal particle size of coal slurry; it is more related to system reactions and the structure of the quenching chamber. In addition, key factors and flocculants have the greatest impact. I have the view that as long as the flocculation is good and the solid content is low, the water quality of the system will be good.
Maybe I didn’t explain it clearly; I’m just guessing that changes in the particle size distribution of the coal slurry lead to changes in the reactions within the furnace, which in turn affect water quality.