Water waste is commonly deemed an undesirable, however inevitable by-product of mining processes. Yet fashionable pump sealing know-how exists which may nearly get rid of this waste while conserving power, enhancing pump reliability and attaining long run operational financial savings.
Water is probably one of the most important, and more and more imperilled, sources on earth. That a lot is known and acknowledged by industries throughout the globe.
However, it is also some of the unnecessarily squandered assets in mining operations. And while the industry has begun to embrace efficiency and sustainability-led advances similar to automation and renewable vitality, it remains steadfastly set in its methods when it comes to slurry pump know-how.
Three approaches are routinely specified by pump manufacturers to seal slurry pumps: mechanical packing, expellers (also often identified as ‘dynamic’ seals’) and single mechanical seals. All include vital limitations, together with poor reliability, decreased mean occasions between failure (MTBF), intensive maintenance necessities and better operational costs.
These factors alone should give mine managers cause for a re-evaluation of the sealing strategies used on slurry pumps. However, any firm with a commitment to the International Standards Organisation ISO-14001 Standard for environmental administration methods and ISO-50001 Standard for vitality management techniques should take observe of the extreme water waste and high energy consumption that results from choosing these conventional sealing methods.
Inefficient sealing When used to seal the method pumps in a mine’s scrubber and floatation circuits, gland packing, single mechanical seals and expeller seals all demand one of the wasteful aspects of slurry processing which is seal flush water injection.
On gland packed pumps it’s important that packing is flushed with clear water to maintain it cool and lubricated, whereas each single slurry seals and expellers require a provide of cool, clear flush water to be injected into the process at high stress, sustaining a secure fluid film between the fragile seal faces to maintain them cool and lubricated, whereas forcing the damaging slurry away.
The flush water required in all three sealing approaches is supplied from an exterior source and injected into the process at a higher stress than the stuffing field pressure, consistent with the trade normal American Petroleum Institute (API) Piping Plan 32. Water which doesn’t leak onto the ground or into the method is distributed to the tailings dam. This also has an effect on the water balance of the plant.
This method constitutes a loss of clear water amounting to billions of gallons a 12 months globally. One large, standard slurry pump usually consumes 10 US gallons (37.eight litres) per minute, amounting to 5.2 million US gallons (19.6 million litres) of water yearly – a surprising statistic by any measure.
At a time when international water provide is predicted to fall in need of demand by some 40% by 20301 , removing unnecessary use of this priceless useful resource ought to arguably be a central plank of any accountable sustainability programme. Yet excessive water use, and the higher vitality consumption it entails, remain embedded in the processes of many mining corporations. Worse still, it is honest to say that it’s usually accepted as merely ‘par for the course’ by reliability engineers and administration alike.
But the very fact is that water waste on any scale is a very pointless characteristic of slurry operations as it can be nearly completely eradicated simply by using superior double mechanical seals and fashionable water administration support methods.
Improve reliability The kind of seal selected, the surroundings by which it operates, and crucially, the tank help system which supplies the water to maximise seal life, mix to provide the solution to excessive water waste and energy use.
Modern double mechanical seals have two units of faces, one sealing to the method fluid and one to ambiance, with a barrier house between the two. They are designed to satisfy the arduous requirements of heavy responsibility slurry functions, with fortified metallic components which are highly immune to corrosion and erosion. Large ports and increased radial clearances mean the lubrication which is important to optimising seal life is maintained constantly and persistently.
A pressurised barrier tank system is central to the environmental sustainability of this resolution. It employs a thermosiphon process which supplies clean, cool water to the barrier space between the double seals at a pressure greater than the product pressure, ensuring a consistent, secure and clean fluid film to keep the seal faces cool and lubricated.
As the mechanical seals generate heat, the hot water within the barrier space rises to the tank and is radiated to the ambiance, permitting the cooler, denser water to sink again down to offer cool lubrication to the seal faces. Most importantly, the flush water is consistently recycled, flowing across the seal faces in a continuous loop and decreasing leakage to the absolute minimal, roughly a teaspoonful a day.
While API Plan 32 is unsuitable for servicing a quantity of slurry pumps in a ‘series train’ with out the need to install special pump methods, pressurised barrier tanks provide scores up to 435 psi (30 bar), making them perfect for these functions. Self-topping and self-pressurising, they are also almost maintenance-free.
Where no plant water provide is available for topping up the tank methods, or the availability has inadequate stress, fluid delivery models could be chosen to produce the barrier fluid to seal faces. These have the added advantages of with the power to supply a water/glycol combination or oil to provide freeze safety in extraordinarily cold climates.
Wide-ranging benefits The benefits of upgrading to fashionable sealing options and assist methods were felt by a coal mine in Poland using a slurry pump to supply coal mud at 9 bar (135 psi) to filter press. Flushed packing resulted in big dilution of product, leading to significantly elevated filtration occasions and prices. The pump was sealed with a double mechanical seal designed to satisfy the arduous requirements of the process.
The supporting seal tank system decreased leakage and product dilution to virtually zero. Return on เครื่องวัดแรงดันเกจที่นิยมใช้ was swift and the financial savings long-term. The advantages by means of water conservation have been equally longlasting and the company’s popularity enhanced.
The mining trade should deal with a tough and expensive challenge in relation to maintaining rotating equipment. But the planning, processing and disposal of flush water constitutes an operational and financial burden which is completely avoidable.
And when a company can eliminate water waste simultaneously rising reliability and lowering long term operational costs, the choice to upgrade to modern techniques ought to certainly be a moral imperative as properly as making sound enterprise sense.