Gaseous Diesel Emissions have long been a major reason for concern due to the health risks that they induce. In underground mines with diesel equipment, these gaseous emissions are a significant contributing factor for the determination of ventilation rates. These rates are used to dilute the emissions to safe levels below the occupational exposure limits.
The initial challenge
Diesel emissions predominantly include carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2) and sulphur dioxide (SO2). While SO2 levels can be lowered by selection and use of low-sulphur fuels, and CO can be converted to the less hazardous carbon dioxide (CO2), nitrogen oxides NOx (NO+NO2) are harder to manage. The reason for this is most measures targeted as a reduction of NOx in the combustion process can lead to an increase of Diesel Particulate Matter (DPM), another undesirable by-product of Diesel combustion. Therefore, with a recent focus on lowering occupational exposure limits of both DPM and NOx, the exhaust treatment has become more and more complex to accommodate for both needs.
Due to the major importance of diesel emissions on the ventilation in a mine, legislation in many countries require compliance checks for gaseous diesel emission regularly. These requirements can vary between daily/monthly checks, checks based on engine run time, and checks after repair or changes of components. Also, the allowable emissions and concentrations as well as the required test procedures can vary.
Opportunities for additional benefits
While compliance checks can sometimes be seen as interfering with the operational goal of production and engine uptime, there is a second dimension to emission testing that is gaining more traction and combining the necessary with the useful. In the past, data from compliance checks had been used solely for compliance measurement and provided little additional benefit to the mine itself. In modern times, mining companies are now looking at diesel emission values from these compliance checks and derive trends for engines as a pre-indicator for defects and a tool to enhance engine maintenance. If integrated in the regular engine maintenance intervals and evaluated properly, this data can be used to adjust maintenance schedules to avoid breakdowns, provide spares in advance, and even improve fuel efficiency. All these aspects can result in a significant increase in engine uptime and thus operational efficiency and increased productivity. This makes emission testing an attractive tool even for surface mines as these financial gains from engine health management are independent from the purpose or requirement of providing proper ventilation to an underground environment.
The solution
Dräger have been providing electronic diesel emission testing devices since 1990. The Dräger EM200-E is a portable and handheld emission testing device tailored directly for the needs of the mining environment. The compact, yet highly shock resistant unit provides the capability for real-time measurement of CO and NOx (NO+NO2) with long-lasting electrochemical sensors to accommodate for the harsh environment experienced in underground or above ground workshops. In non-Ex environments it can even be used throughout the mine eliminating the need for engines to return to workshops for emission testing. Differences in altitudes that are common for deep mines or in high altitude locations are easily compensated for with an integrated absolute pressure sensor for even more accurate results. The user is guided with an easy-to-use menu-driven measurement sequence and can log values for different engine states such as idle, high idle or load in the data storage together with respective rpm and engine name for proper documentation. An alternative setting enables the user to perform measurements pre and post scrubber to evaluate and document scrubber efficiency. These logged values can be printed wirelessly or have data exported to facilitate further analysis and storing.
The Dräger EM200-E is specially tailored for the needs of the mining environment and provides all the necessary features to not only fulfill the legal requirements for compliance checks, but also provides a tool that can be an integral part of procedures for emission based predictive maintenance, cost savings, and increasing productivity throughout the mine.
www.draeger.com
1800 372 437
Add Comment