Diesel Filtration In The Mining Industry

The last thing a mine needs is for production to be stymied by equipment failures caused by contaminated diesel. Effective fuel filtration solutions can prevent this.

The effectiveness of a diesel engine depends largely on how good its fuel filtration system is, particularly as the results of poor filtration are far more problematic than black smoke from the exhaust and a lack of engine horsepower for the vehicle.

In a tough economy, rapidly escalating operating costs – not only regarding fuel, but also the expense related to unexpected equipment downtime – along with increasingly strict environmental legislation around greenhouse gas emissions have left organisations with large diesel fuel user bases facing very difficult challenges.

Organisations that operate fleets of small to large diesel-powered vehicles need to ensure optimum engine performance and reliability. Most especially, says Hydac Technology sales manager Jannie Botha, particulate and water contamination in diesel fuel must be controlled to acceptable, or within specification, limits.

Filtration challenges

“The mining industry operates a multitude of different types of equipment that require diesel that is properly filtered to ensure optimum operations. Whether we are talking plant equipment, mine vehicles of all sizes or simple generators, ‘dirty’ fuel is a menace to effective use,” he says.

“Improperly filtered fuel affects not only your consumption thereof, but also the quality of service obtained from the equipment, as well as its eventual length of life. It leads to an increase in equipment failure, and to more equipment standing idle for longer periods, which ultimately means your bottom line will feel the impact.

“On the other hand, effective fuel filtration most certainly increases availability and reduces downtime, something that is absolutely critical in an industry that is extremely production-driven.”

Botha notes that all fuel contains some water in suspension, but because diesel is less refined, it holds more water than other fuels. He says additional water can find its way into the fuel from cross contamination, such as through diesel theft. When fuel is stolen, the missing liquid is often topped up with paraffin or water, he explains, causing trouble for the purchaser’s equipment in the end.

“In addition, the storage of diesel fuel also creates an environment that allows for more water contamination, as air containing water vapour gets into the tanks during the dispensing process, and this leads to more water molecules in the fuel as this condenses into water droplets inside the storage tank.

“Even once the fuel is on board the vehicle, there is still a possibility of the fuel becoming more ‘watered down’, as in the standard operation of the engine a certain percentage of diesel used for injector cooling is returned in a heated state back to onboard diesel tanks, which obviously leads to additional condensation.”

More efficient filtration

Besides the challenges this can create, including the costs related to vehicle repairs, a loss of productivity and less efficient fuel consumption, there are other costs for e.g. replacement storage tanks should these tanks rust, he says.

Moreover, he says, mining depends on energy, which is problematic in a country that frequently has to deal with load shedding. To overcome this, many mines use backup generators for power, and efficient filtration is also key here, because “dirty” diesel can lead to generator failure, leaving the mine bereft of power during a blackout.

“Standard on-board fuel filters today are not really capable of handling high levels of diesel contamination. Therefore, to prevent premature plugging and frequent change-outs of these fuel filters, fuel cleanliness should be controlled throughout the entire fuel supply chain.

“To put this into perspective, newly delivered bulk diesel fuel typically has an ISO cleanliness level of ISO 22/20/18 to ISO 21/19/17, but today’s injection fuel systems require a fluid cleanliness level below ISO 14/11/9 – essentially the same level of cleanliness as aerospace fuel.”

He says Hydac Optimicron Diesel filter elements have been specially developed for the filtration of diesel, and are characterised by very high contamination retention capacity, coupled with low pressure drop.

This has resulted in extended service life for these elements. Use of the most up-to-date materials further guarantees excellent separation rates, even in a single pass, and this continues over the entire element life cycle while in operation, he says. The Hydac Optimicron two-stage diesel dewatering elements use materials specifically designed for coalescing and for separating water from diesel. These elements enable a secure efficient dewatering capability, even at greater quantities of water in diesel.

End-to-end filtration

“This helps the organisation achieve the lowest cost of ownership, while at the same time significantly improving production, because vehicle breakdowns are reduced. In addition, the equipment will have a longer lifespan,” he says.

“At Hydac, our product range actually includes something for every step of the process, from production to consumption. In other words, we can assist with key diesel filtration solutions from the refinery to the ship, and from the tanker to the storage tank on the mining site, and from there to the mobile bowser and into the actual plant equipment.”

He says Hydac can also help with “fuel polishing”, which helps to avoid the challenge created by fuel stored for longer periods. Mining sites buy a lot of fuel, which is often stored for lengthy periods, and this can lead to issues with water condensation inside the tank. The fuel is polished by shifting it from one tank to another, which enables it to undergo a filtration process.

“We also offer on-board filtration solutions that help to filter the fuel between the plant equipment’s fuel tank and the main engine filter.”

From a sustainability perspective this is also positive, as all equipment using these filters has lower levels of exhaust emissions, thanks to using cleaner fuel.

“Cleaner fuel also ensures your fuel injectors are able to last longer. Ultimately this means you save costs in respect of reduced equipment repairs, lower levels of fuel consumption, and, of course, fewer major serious equipment failures caused by diesel contamination,” he says.