Study Of Dust Generation Law And Control Technology In The Sifting Workshop Of Hecaogou Coal Preparation Plant

The sifting workshop of coal preparation plant is where the dust pollution is the most severe,as there are various types of dust and the dust concentration is high.Moreover,respirable dusts which make up the most of the percentage are the most harmful dusts with extremely high morbidity.The current dust control technology has defects in real practice.Its dust elimination efficiency is far from meeting the needs of safe production.That's why dust control is urgent.Based on the Program of Dust Control in sifting workshop of Hecaogou Coal Preparation Plant,methods of on-site test,theory analysis and numerical simulation are carried out to conduct research on the dust generation pattern from different origins in the sifting workshop,physical characters of the dusts,as well as the improvement on the parameters of the most applicable dust control technology.The major conclusions are as below.Study on the physical characters of dusts,the dust generation mechanism and spreading pattern in the sifting workshop is carried out.The concentration of dusts in screen house is up to 780 mg/m³,with 49%⁶4%of respirable dusts and4.80%⁵.40%of SiO₂,much higher than the allowable value of national standards.It does great harm to the security as well as mental and physical health of the workers.According to the national standards,the goal of dust of dust control is to keep the concentration lower than 10 mg/m³,with respirable dust concentration lower than3.5mg/m³.Geometry models of classification screen system for raw coal in major dust origins in sifting workshop and lump coal crushing system are established to simulate the pattern of dust generation and spread.Through the analysis on the influencing factors of generating dusts in sifting workshop,By modifying the structure of the Clay Groove,the dust concentration at the outlet can be reduced to some extent by adding a feeding spoon at the bottom of the clay groove.The angle of the feeding spoon of the sifting workshop is about 45,which can effectively control the impact airflow and the induced airflow,and reduce the dust concentration.After the study on characters of dusts in the sifting workshop,as well as analysis and comparison on dust control technologies,pulsed jet bag filter and siphon-type micro-mist dust elimination technology are combined together to control the dusts in the sifting workshop.Also installation position and chute of the dust precipitator are optimized.After the optimization,208 conveyor chute is 8.5m,1.2m away from the edge of the discharge chute.301 conveyor chute is then modified to 15m,1.6m away from the edge of the discharge chute.According to the on-site tests and numerical simulation,the dust concentration basically meets the national standards.This proves the feasibility of this technology.