Upgrading of 6-0 mm low rank high sulfur lignite by a compound dry cascade separation bed

Abstract

In this paper, the effect of vibration intensity on the spatial distribution of sulfur content in bed particles was studied. The effects of vibration and airflow on the mechanical characteristics of particles were studied, the collision behavior mode of particles was determined, the spatial saltation law of particles was investigated, the spatial functional axis of beds was determined, and the saltation separation period of particles was determined. The test results show that: When separation bed provides inlet airflow velocity (U_in) is 2.55 m/s, the airflow distribution interval of I, II and III areas were U_I=2.55-2.57 m/s, U_II=1.33-1.35 m/s, U_III=0.35-0.38 m/s, respectively; when separation bed vibration amplitude (A) A=2.4-2.5 mm, separation bed vibration frequency (f) f=23-24 Hz, the desulfurization effect is the best. When vibration intensity (Γ) Γ=1.22, U_in=1.05 m/s, the particles have disordered contact and collision behavior. When Γ=14.89, U_in=3.18 m/s, the particles have a transition cataclastic collision. When Γ=5.80, U_in=2.55 m/s, the particles have directional collision behavior. It is determined that the OX axis is the transverse stable diffusion axis of the material, the OY axis is the longitudinal gradient transport axis of the material, and the OZ axis is the vertical density cascade distribution axis of the material. When separation time (T) T=0-10 s was the period of disorderly diffusion and mixing of particles, T=10-20 s was the period of directional migration and stratification of particles, and T=20-30 s was the period of cascade distribution and separation of particles. Finally, separation experiments conducted under optimal operating parameters demonstrated that the clean coal yield was 72.02% with a sulfur content of 0.98%.

Keywords

Low rank high sulphur lignite / Compound dry cascade separation bed / Desulfurization and ash reduction / Particle space transition

Acknowledgements

This study was supported by Science and Technology Project of Hebei Education Department (No. ZD2022128) and Tangshan Science and Technology Plan Project (No. 22130226H).

References

[1] Gao MZ, Li HM, Zhao Y, Liu YT, Zhou WQ, Li LM, Xie J, Deng J. Mechanism of micro-wetting of highly hydrophobic coal dust in underground mining and new wetting agent development. Int J Min Sci Technol 2023; 33(1):31-46.

[2] Yu XD, Luo ZF. Study on water transfer characteristics and desulfurization effect during the separation of fine low rank lignite in the dry dense medium fluidized bed. Fuel 2024; 372:132194.

[3] Mo Q, Liao JJ, Chang LP, Han YN, Chaffee AL, Bao WR. Study on combustion performance of hydrothermally dewatered lignite by thermal analysis technique. Fuel 2021; 285:119217.

[4] Hao H, Liu ZW, Zhao FQ, Du JY, Chen YS. Coal-derived alternative fuels for vehicle use in China: A review. J Clean Prod 2017; 141:774-90.

[5] Hirota N, Ando T, Takano T, Okada H. In-situ observation of particles deposition process on a ferromagnetic filter during high-gradient magnetic separation process. J Magn Magn Mater 2017; 427:296-9.

[6] Hatakeyama Y, Inaba K, Kofu K, Miura H. Reduction of particle-wall friction and separation of mixed particles by ultrasonic. J Soc Powder Technolo, Japan 2016; 53(2):74-84.

[7] Xu LY. Process and equipment modification in Lianchuang coal preparation plant. Coal Qual Technol 2009.

[8] Dong L, Zhou EH, Cai LH, Duan CL, Zhao YM, Luo ZF. Fluidization characteristics of a pulsing dense-phase gas-solid fluidized bed for high-density separation of fine anthracite. Energy Fuels 2016; 30(9):7180-6.

[9] Dong L, Zhang B, Zhang Y, Zhao YM, Zhou EH, Lv P, Duan CL. Kinetic characteristics of the particles in a dense-phase pulsed fluidized bed for dry beneficiation. Can J Chem Eng 2017; 95(6):1133-40.

[10] Muhich CL, Ehrhart BD, Al-Shankiti I, Ward BJ, Musgrave CB, Weimer AW. A review and perspective of efficient hydrogen generation via solar thermal water splitting. Wiley Interdiscip Rev Energy Environ 2016; 5(3):261-87.

[11] Liu WB. Distribution characteristics of remaining oil in Shajiagou area of Ordos basin and suggestions for subsequent development. Petrochem Ind Technol 2016; 23(1):271-2. in Chinese.

[12] Yang XL, Zhang YD, Yang Y, Zhou EH, Fu ZJ, Zhao YM. Fluidization of Geldart D type particles in a shallow vibrated gas-fluidized bed. Powder Technol 2017; 305:333-9.

[13] Yu XD, Luo ZF, Li HB, Yang XL, Zhou EH, Jiang HS, Wu JD, Song SL, Cai LH. Effect of vibration on the separation efficiency of high-sulfur coal in a compound dry separator. Int J Miner Process 2016; 157:195-204.

[14] Jiang Y, Chen ZQ, Shao HN, Zhao YM, Luo ZF, Tan MB, He JF, Liu FS, Hong P. The effect of a porous medium on fluidization characteristics in air dense medium fluidized bed. Powder Technol 2016; 301:1227-34.

[15] Otwinowski H. Cut size determination of centrifugal classifier with fluidized bed/wyznaczanie ziarna granicznego klasyfikatora od{s´}rodkowego Z warstw {a˛ } fluidaln{a˛ }. Arch Min Sci 2013; 58(3):823-41.

[16] Wu HD, Han W, Wang DD, Gao L. A carbon oxidation factor regression model of coal-fired power plants in China. J Clean Prod 2017; 142:4403-11.

[17] Ma FQ, Ding EJ, Jin N, Tan DJ. Intelligent control for jigging process. J China Univ Min Technol 2002; 31(3):293-7. in Chinese.

[18] Dwari RK, Hanumantha K. Dry beneficiation of coal: A review. Miner Process Extr. Met Rev 2007; 28(3):177-234.

[19] Espin MJ, Quintanilla MAS, Valverde JM. Magnetic stabilization of fluidized beds: Effect of magnetic field orientation. Chem Eng J 2017; 313:1335-45.

[20] Patil DP, Parekh BK. Beneficiation of fine coal using the air table. Int J Coal Prep Util 2011; 31(3-4):203-22.

[21] Kumar P, Sah R, Ari V, Das A. Dry beneficiation of coal fines using air table. In: Proceedings of the XI International Mineral Processing Technology. Jamshedpur: NML; 2011.p. 446-51.