Effect of Cone-Plate Clarifier Structure Parameters on Flocculation Efficiency

In this study, a coal mine water flocculation system was established. A series of flocculation tests were carried out at different structural parameters (cylinder height, cone-plate insertion depth and cone-plate spacing) to better investigate the effect of the cone-plate clarifier on coal mine water treatment performance. Sixteen sampling points were set up in the system for data monitoring to generate the required data. The cone-plate clarifier was divided into five zones for flocculation analysis. The increased cylinder height facilitated the flocculation of particles in the micro flocculation zone and the settling of particles in the settlement zone. The chemicals used are polyaluminum chloride (PACl), Fe3O4 and polyacrylamide (PAM), corresponding to doses of 60 mg/L, 40 mg/L and 6 mg/L, respectively. Insufficient insertion depth of the cone-plate will cause the small flocs that have not been fully flocculated to enter the exit pipe zone directly through the cone-plate, while too much insertion depth will cause the large floc in the settlement zone to re-enter the exit pipe zone. The flocculation effect of small flocs increased as the cone-plate spacing decreased, which is consistent with the shallow pool theory. When the cone plate spacing was too narrow, the amount of fluid was reduced and the increase in fluid velocity reduced the flocculation effect. Curve fitting was conducted for Suspended solids(SS) and turbidity removal efficiency under each structural parameter to derive the variation of SS and turbidity removal efficiency under different structural parameters. The regression models of SS and turbidity removal efficiency on the cylinder height, cone-plate insertion depth and cone-plate spacing were established based on the curve fitting results, and the regression models were verified to be well fitted based on the comparison of experimental results. Finally, the optimal values of SS and turbidity removal efficiency were found based on the regression model. The flow rate of the cone-plate clarifier is 0.6 m3/h. The SS removal efficiency reached 96.82% when the cylinder height was 708 mm, the cone-plate insertion depth was 367 mm and the cone-plate spacing was 26 mm. The turbidity removal efficiency reached 86.75% when the cylinder height was 709 mm, the cone-plate insertion depth was 369 mm and the cone-plate spacing was 26 mm.

Construction and Application of Flocculation and Destability System of Biodrill-A Drilling Fluid in Bohai Oilfield

To protect the marine ecological environment of Bohai Bay, the waste drilling fluid in Bohai oilfield have to be treated. In the light of the composition characteristics of Biodrill-A drilling fluid, the compounding method of the inorganic–organic flocculants was adopted to assist the flocculation and solid–fluid separation of Biodrill-A drilling fluid. Through the orthogonal test design, the main factors impacting the flocculation effect on Biodrill-A drilling fluid were found to the concentration of inorganic flocculant CaCl2 and the flocculation pH value. The optimal flocculation treatment was further obtained through single-factor optimization. Specifically, when the inorganic flocculant CaCl2 concentration was 0.9 w/v%, the organic flocculant concentration was 0.01 w/v%, the flocculation pH was 8, and the flocculation time was 7 min. Eventually, the final dewatering rate could reach 84.02%. In the optimized compound flocculants, the inorganic flocculant CaCl2 reduced the zeta potential of clay particles by electric neutralization to decrease the repulsion among particles, and the organic one could absorb and wrap the clay particles through bridging curling and electric neutralization after flocculation destabilization. Both inorganic and organic flocculants facilitated the large flocs and particles of clay particles. The field test showed that the inorganic–organic flocculants were suitable for the on-line flocculation treatment process based on centrifugal machine. The waste drilling fluid was reduced by 82%, and the water content of the separated solid phase was as low as 25.7%.

Research on the Settlement Performance of Flocculants on the Sediment of Mine River

In view of adding different flocculant to the mine river sediment, the influence of different flocculants on the sedimentation performance of the mine river sediment was investigated. The experimental results show that the selected flocculant, cationic polyacrylamide (CPAM), has an evident effect on the flocculation and settlement of the mine river sediment. The final flocculation effect was enhanced with faster settling speed. The flocculation effect was optimized when 10 mL CPAM flocculant (0.2wt%) was added, followed by 3 minutes of stirring. The dewatering effect of the flocculated sediment can be enhanced with decreased solid content of the sediment.

Conductive rubber with the effect of positive temperature resistance from the tire regenerate

The possibility of developing conductive rubber based on tire regenerate and conductive carbon black OMCARB CH85 is shown. The vulcanizing characteristics of the regenerates obtained by thermomechanical devulcanization using a curing group and conductive carbon black were studied. It is shown that after thermomechanical devulcanization, preservation of sulfide bonds, re-vulcanization occurs only in the presence of sulfur and vulcanization accelerators. A flocculation effect was detected upon the introduction of OMCARB CH85 into the regenerate.It is shown that tensile strength and Shore A hardness are increase with an increase in the content of conductive carbon black in the regenerate. However, there is insufficient dispersion of carbon black, a decrease in elongation at break and resistance to abrasion is observed. The study of volume resistivity showed that the resulting rubbers belong to semiconductor materials. The dependence of resistivity on temperature in the range from 10 to 80 °C is constructed. It is shown that the effect of a positive thermal coefficient is observed in all samples. The values of the positive temperature coefficient of resistance in the temperature range of 10 – 80 °C are 0.054 – 0.285 deg–1.

Preparation of organic polymer flocculant and its application in drilling fluid

A flocculant (DES0-0) was synthesized by epichlorohydrin and diethylamine, followed by adding crosslinking agent such as ethylenediamine, diethylenetriamine and triethylenetriamine to obtain the crosslinked polymer DES0-1, DES0-2, DES0-3. The flocculation effect of DES0-1, DES0-2, DES0-3 and PAM was studied by measuring the volume, transmittance and particle size of the clarified solution after flocculation. The results showed that the flocculation effect of triethylenetetramine crosslinked polymer (DES0-3) and PAM was better. Meanwhile, the flocculation effect was more optimistic in the strong alkali environment.