某热电厂输煤系统粉尘污染治理效果分析

Effects of Comprehensive Dust Control Program on Coal Transfer System of a Thermal Power Plant

[目的]分析评价某热电厂输煤系统粉尘综合治理设施的防护效果,从职业病防护角度提出合理可行的防护建议,以保护劳动者职业健康。[方法]采用职业卫生现场调查和职业卫生检测方法,检测内容包括粉尘(总尘)浓度、分散度、游离二氧化硅(SiO2)含量及除尘系统罩口控制风速。[结果]粉尘游离SiO2含量为4.6%～7.4%,平均为6.0%,该厂输煤系统粉尘类型确定为煤尘;粉尘分散度为<5μm的粉尘占77.0%。治理前,粉尘作业点总尘浓度均超过卫生标准限值,超标率达100.0%;治理后,粉尘浓度超标率下降,但仍存在超标现象,超标率为40.0%;超标作业点分别为翻车机房、煤场、碎煤机旁、犁煤器旁,超标工种主要有螺旋卸煤机操作、碎煤机操作、煤仓间操作。吸尘罩罩口风速检测表明,碎煤机、煤仓间吸尘罩风速偏小,未达到设计值。[结论]该热电厂对粉尘作业场所采取的治理措施取得了一定防护效果,粉尘污染状况明显好转,但仍然存在超标作业场所,粉尘防护设施有待进一步完善。

[Objective]To analyze and evaluate the protective effects of a comprehensive dust control program on coal transfer system of a thermal power plant,and to put forward reasonable and feasible countermeasures for occupational disease prevention to protect workers’ occupational health.[Methods]Field investigation and detection of occupational health hazards were carried out to evaluate total dust concentration,dispersity,free silica content,and wind speed at dust hood exits.[Results] The free silica content ranged from 4.6% to 7.4% with an average of 6.0%.The type of dust in the coal transfer system of the plant was confirmed as coal dust.The dust dispersity was 77.0% for particles less than 5μm.Before the dust pollution control program,the total dust concentrations of all workplaces exceeded occupational health standards;the unqualified rates of total dust concentrations decreased to 40.0% after the dust pollution control program,including workplaces such as car dumper room,coal field,and the vicinity of coal pulverizer and coal plough.The workers responsible for running screw coal unloaders,coal crushers,and bunker bays were the main population that suffered from exceeded limits on total dust concentrations.The wind speeds at dust hood exits of coal crusher and bunker bay did not meet the design values.[Conclusion]Dust pollution in the selected coal transfer system has been significantly reduced after control program applied.Dust removal facilities should be further improved to fully address the dust pollution issues.