Research On Interface Regulation Of The Agglomeration Separation Process Of Liquid CO₂ For Coal Macerals

The long-flame coal in Bulianta of Shendong was taken as the research object.Based on the separation and concentration for coal macerals by liquid CO₂ hydrophobic agglomeration,the interface characteristics of the agglomeration separation process of coal macerals were studied,which strengthened the collision and agglomeration between liquid CO₂ and vitrinite.So as to improve the effect of liquid CO₂agglomeration separation of coal macerals.The research contents are as follows:Adoption of industrial and elemental analysis and maceral composition test,it was found that the ash content of test coal samples was lower（Aad=3.91%）,the volatile content was higher（Vdaf=34.61%）,and vitrinite content was 39.82%.The density composition of test coal samples was investigated.The vitrinite enrichment area was1.23-1.26 g/cm³,and the inertinite occurrence interval was 1.39-1.41g/cm³,and vitrinite and inertinite were separated and enriched.The Zeta potential of vitrinite and inertinite were-32.09m V and-42.41m V respectively,and then the enriched vitrinite and inertinite were prepared into pressed pellet after fine grinding.The surface roughness and wettability of the pressing tablets were measured.The surface roughness of vitrinite and inertinite were 0.402 and 0.493 respectively.The contact angle of vitrinite and inertinite were 99.84°and 65.76°respectively.The Joule heating carbonization of vitrinite and inertinite was studied,comparing the changes of surface functional groups,phase structure and pore structure before and after carbonization.Compared with vitrinite and inertinite,the carbonation products have lower aliphatic content,higher carbon-carbon double bond content and mineral disappeared.The vitrinite and inertinite exist in the form of amorphous carbon.After carbonization treatment,the vitrinite flash products show obvious 2-H phase graphene structure,while inertinite flash products show 3-R phase graphene structure,and the graphitic degree of inertinite flash products is higher than vitrinite flash products.After carbonization,the specific surface area of vitrinite decreases greatly and the pore size is 4 times of that before carbonization,while the specific surface area of inertinite increases greatly and the pore size becomes 1.5 times of that before carbonization.The effect of electrochemical regulation on the interface characteristics of vitrinite and inertinite were studied.With the increase of p H value,the wettability of vitrinite decreased first and then increased,while the wettability of inertinite increased all the time.When p H=3,the hydrophobic difference between vitrinite and inertinite reach maximum.With the increase of Al Cl₃ dosage,the hydrophobic difference of macerals increases gradually.When the Al Cl₃ concentration is 200mg/L,the difference of wettability between vitrinite and inertinite is the largest.At the interface between vitrinite and inertinite,the adsorption capacity of vitrinite to DDBAC was always lower than that of inertinite.With the increase of the dosage of DDBAC,the hydrophobic difference between vitrinite and inertinite decreased all the time,so DDBAC had no effect on enlarging the hydrophobic difference between vitrinite and inertinite.Sodium dodecyl benzene sulfonate（SDBS）in the vitrinite and idler group interface is given priority to with hydrogen bonding and hydrophobic adsorption,an increase in the amount of SDBS make the wettability of vitrinite presents the change trend of increase with the decrease of the first,and idle of wettability change is not big,when SDBS concentration of 100 mg/L,vitrinite and inert mass group differences between wetting,the maximum Therefore,the addition of SDBS can effectively enlarge the hydrophobic difference between vitrinite and inertinite.Experimental study on electrochemical regulation on the effect of agglomeration separation and concentration for coal macerals with liquid CO₂.The results showed that the vitrinite content and recovery increased firstly and then decreased with the increase of p H value.When p H=3,the vitrinite content in hydrophobic aggregation reached74.21%and the recovery was 38.68%,both of which reached the maximum value.When p H was higher than 3,vitrinite content decreased significantly,while vitrinite recovery decreased slightly.With the increase of the dosage of Al Cl₃,the vitrinite content and recovery showed a trend of first increased and then decreased.When the dosage of Al Cl₃ was 200mg/L,the vitrinite content in hydrophobic aggregation reached77.35%and the recovery was 37.1%,reaching maximum.With the increase of SDBS dosage,the vitrinite content and recovery increased firstly and then decreased.When the dosage of SDBS was 100mg/L,the vitrinite content in the light product was 79.77%.The recovery of vitrinite was 42.67%.There are 30 figures,18 tables and references 96 in the thesie.