Customised Diesel Particulate Filtration Technology for Mining Machinery

Reducing Tailpipe Emissions from the Source

John Ratcliffe’s HJS Emission Technology SMF® Filter with an efficiency of up to 99% in the reduction of ultrafine DPM particles emitted from the engine’s tailpipe. Characteristically, these filters reduce diesel equipment’s’ tailpipe DPM limits from as much as 16000ug/m3 to within the requirements set.

Legislation in different countries in Africa necessitates mining companies to implement measures aimed at limiting the levels of Diesel Particulate Matter (DPM) emissions from machinery. In South Africa’s context, a circular which the Chamber of Mines sent out in 2012 set the goal of DPM exposure control value of 160ug/m3 (TC) by 2016. Thus, diesel filter technology is a necessity in any engine as diesel engine technology cannot reduce emission limits on its own over the lifespan of the engine. However, while mining companies may do their utmost to achieve the legislated threshold by using Diesel Particulate Filters (DPF’s), their well-intentioned efforts may fall short, as recent evidence has suggested.

Limited availability of relevant products

John Ratcliffe, a company that provides diesel particulate filtration solutions to diverse industries, has solved complex problems in emissions reduction for over forty years for clientele in the mining sector. The company’s Chief Executive Officer, André Robberts, observes that the biggest challenge which mine operators face is limited availability of relevant products, even though there are various types of Diesel Particulate Filters (DPFs) out there. “Various types of DPFs – ranging from paper, ceramic to metal DPF’s – vary in efficiencies and lifespan.

The DPM exposure control value of 160ug/m3 (TC) is a time-weighted average in ambient air. Although it was identified that diesel machinery was the major contributor to higher than accepted levels, the question was asked on what limits the machinery can be reduced to, so as to achieve the GEE’s recommendations.”

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Inherent limitations in conventional DPFs

Evidently, there are inherent limitations in some, if not most, conventional DPF’s. In particular, although full flow (99% efficient) filters are the solution for healthy engines, it has been established that unhealthy engines or partial flow filters will not achieve these results. For instance, workers (operators) could still be exposed to high levels of DPM, under three conditions: If the engine or Tier Rating is outdated; the engine is not performing or maintained according to standard; and the incorrect filter is fitted to the machine.

John Ratcliffe’s solution   

Recognising the urgency of the situation, John Ratcliffe decided to devise a solution. The objective was to find diesel filter technology that could reduce the tailpipe DPM emission to as close as possible to the limits at the source, so that appropriate ventilation should be able to cope with ambient exposures.

After years of exhaustive research and development, the team at John Ratcliffe launched HJS Emission Technology SMF® Filter in 2013. Compellingly, the HJS Emission Technology SMF® Filter with an efficiency of up to 99% in the reduction of ultra-fine DPM particles proved to be the solution. Characteristically, these filters reduce diesel equipment’s’ tailpipe DPM limits from as much as 16000ug/m3 to within the requirements set.

HJS Emission Technology fills the gap

In several ways, HJS Emission Technology SMF®, which has a modular design, addresses limitations of conventional Diesel Particulate Filters (DPFs) which are awash in the market. Mainly, these are reduced downtime and replacement costs. Also, the team at John Ratcliffe are able to offer predictive maintenance which ensures availability.

  1. Decreasing downtime, increasing availability

Increasing equipment uptime (availability) and decreasing downtime is the main focus in contemporary mining. Mines need their equipment to be working with minimal disruption at all times.  Yet frequent downtime is often registered with conventional filters, due to long hours of cleaning and frequent need for cleaning.

The SMF® stainless steel filter is designed to minimise downtime mainly caused by cleaning, points out Robberts. “The SMF® stainless steel filter could either be swopped out on a rotating basis and cleaned with water within 30 minutes. The filter has a 2000 operating hour cleaning interval on properly maintained machines and is fully recyclable once it has reached it lifespan.”

  1. Replacement costs

While filter wear is inevitable, when it occurs frequently, it can become a huge liability in terms of replacement costs.  And so, HJS Emission Technology SMF® Filter is designed with managing this situation in mind.

The relevance of HSJ Emission Technology becomes clearer when one considers increasing cost of DPFs as one goes up the Engine Tier Level, Robberts indicates. “As you move up the engine Tier level, filters are standard. The higher you move up the engine Tier Level the higher the costs. Typically, in the South African context, depending on the engine size and type of filter system, the cost of fitting a DPF can range from R50 000 to R200 000. This price range is not completely out of the range of what was spent on previous technologies in the last couple of decades such as Catalytic converters, NOₓ Diluters, Multi Gaps, Silencers etc.”

However, replacement costs escalate when filters have to be replaced in short intervals. Thus, this is an area where the HJS Emission Technology SMF® Filter is very convenient, assures Robberts. “The modular design of the system allows for only the component that has been damaged to be replaced and the system could last the lifetime of the machine.”

Timely predictive maintenance

Going beyond supplying products and leaving clientele to their own devices, John Ratcliffe ensures that it offers a solution. Thus, it carries out scheduled testing on the performance of installed DPF’s for clients, which enables timely predictive maintenance. Robberts emphasises the significance of this approach: “Clogged up DPF’s or Catalytic converters are often indicative of engine issues upstream. Hence, we conduct regular engine opacity tests to diagnose engine health. These tests not only protect the DPF but planned maintenance can now be performed on the engine before major breakdowns occur.”

Through John Ratcliffe scheduled testing, a client is able to closely track engine performance. The client’s maintenance teams now identify potential risk machines and track fleet “health” and emissions, whether a DPF is fitted or not.

Immense benefits in machinery

On the whole, there is no question that there are immense benefits of using HJS Emission Technology SMF® Filter in machinery. Generally, the major impact is noticeable in the following areas: How maintenance is done; Reduced engine downtime; Increased productivity, and Reduced DPM exposure. Furthermore, HJS Emission Technology SMF® Filter has proved effective in reducing ear-damaging noise produced by underground equipment which does not have silencers fitted on them.  For instance, fitting a DPF on a machine reduces decibels (dB’s).

Robberts recommends HJS Emission Technology SMF® Filter technology for machinery deployed in underground mines. Additionally, most importantly, he advises maintenance and Ventilation engineers to collaborate in fitting the correct solution with regards to the equipment they currently have.

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OEM’s endorse HJS Emission Technology SMF® Filter

The application engineering team from John Ratcliffe have conducted numerous trial installations with mines in conjunction with OEM’s worldwide. The results have initiated a rollout of the system as OEM products on their machines in Africa and other regions.

Currently, a trial is in process in Australia with one of the biggest OEM machine manufacturers to extend the HJS DPF’s to the rest of their fleet in the soft rock mining sector. These tests followed the success of the flameproofed EXd versions in South Africa.

John Ratcliffe’s Sintered Metal Diesel Particulate Filter (DPF) was installed on mobile machinery at South32’s Wessels Manganese Mine in Hotazel, Northern Cape, South Africa in the month of February 2015. A testimonial from management at South32 confirms the efficacy of the DPF: “Regular testing confirms that John Ratcliffe’s DPF system reduces >99% of DPM’s from the exhaust fumes, both Elemental and Total Carbon. After six months of operational testing, the DPF system has proven to be reliable and is an effective means to reduce diesel particulate matter with limited maintenance effort. The electronic control unit (ECU) installed with the system also assists with fault finding on the machines.”

With the DPF system’s efficacy firmly established, the product is now seen as ready for uptake. At an advanced stage are plans to manufacture mining-specific solutions to bring huge benefits to the end-user. Furthermore, development for a wireless ECU solution, which would enable a client to monitor his fleet in real time, is in progress.


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