Research On Coal Water Slurry Dispersant Adsorption Behavior And Its Influence On Water Occurrence Characteristics

Coal Water Slurry(CWS)technology is one of the important cleaning techniques of coal.Coal water slurry dispersant technology is the key to coal water slurry pulping technology.Dispersants with excellent performance can effectively improve the fluidity,stability and concentration of coal water slurry.However,due to the wide variety of coal and its complex composition and surface structure,with interlaced hydrophilic/hydrophobic groups,the adsorption behavior of dispersants on the coal surface is extremely complex.Research on the influence of dispersant's adsorption behavior on coal surface characteristics,and on the matching relationship between dispersant and coal has become a hotspot in the field of coal water slurry.This thesis studies the adsorption behaviors of four different sturctures anionic polymer dispersants on four coals with large differences in slurry properties and their effects on the surface characteristics: 1)The adsorption process of different dispersants on the coal surface was studied by ultraviolet(UV)spectroscopy and analyzed by Langmuir and Freundlich adsorption models;2)The effect of the dispersant on the slurry properties of the coal water slurry was studied by the Zeta potential and waterloss characteristics test;3)The influence of different dispersants on the surface properties of coal particles,such as the surface free energy was analyzed by two-liquid contact angle method;4)The influence factors of dispersants and coal types on their surface properties were explored by the capillary ascending method through analyzing the wetting behavior of different reagents on coal powder;5)The influence of the dispersant on the water occurrence characteristics of the coal water slurry system was explored by the thermogravimetry(TG)method.The study found that: coal water slurry dispersant with good performance should have a good match with the coal surface.To be specific,the dispersant molecule should have certain molecular weight and molecular weight distribution;the molecular chain should have good flexibility;the dispersant polymer structure should contain aromatic rings or hydrophobic groups similar to aromatic ring to match coal;it should also contain suitable hydrophilic groups.The study found that: 1)The adsorption behavior of the coal water slurry dispersant on the coal surface is mainly related to the matching of the dispersant and the surface characteristics of the coal.The better the matching,the greater the adsorption capacity,and the greater the change of the coal surface properties.PSS dispersant is more suitable for Jining coal and Urumqi coal with better coal quality,and LS dispersant is more suitable for Yulin coal and Hulun Buir coal with poor coal quality.2)The adsorption mechanism of the coal water slurry dispersant is that the adsorption of the dispersant on the coal surface changes the wetting performance and surface free energy of the coal surface,thereby changing the occurrence characteristics of water in the coal water slurry and improving the slurry performance.3)A coal water slurry dispersant with excellent performance should have a good match with the coal surface:it should have certain molecular weight and certain molecular weight distribution,good chain flexibility,aromatic rings or hydrophobic groups similar to aromatic ring and suitable hydrophilic group.Based on the national condition of the rich resources and diverse types of coal,this thesis specifically studies the adsorption laws of dispersants on the surface of coal with different coalification levels,which can play a good guiding role of the design and optimization of dispersants,and the improvement of coal slurry formation through dispersants.In a world,this research has certain theoretical significance and application prospects.