Water waste is often deemed an unwanted, but inevitable by-product of mining processes. Yet fashionable pump sealing expertise exists which might nearly eliminate this waste whereas conserving vitality, improving pump reliability and attaining long term operational financial savings.
Water is amongst the most vital, and increasingly imperilled, resources on earth. That much is known and acknowledged by industries across the globe.
However, additionally it is one of the unnecessarily squandered assets in mining operations. And whereas the business has begun to embrace effectivity and sustainability-led advances corresponding to automation and renewable energy, it stays steadfastly set in its methods when it comes to slurry pump expertise.
Three approaches are routinely specified by pump producers 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, reduced mean instances between failure (MTBF), intensive upkeep requirements and better operational prices.
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 dedication to the International Standards Organisation ISO-14001 Standard for environmental management techniques and ISO-50001 Standard for power administration methods ought to take note of the extreme water waste and excessive power consumption that results from opting for these conventional sealing strategies.
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 clean water to keep it cool and lubricated, while both single slurry seals and expellers require a supply of cool, clear flush water to be injected into the process at high pressure, maintaining a secure fluid film between the fragile seal faces to keep them cool and lubricated, while forcing the damaging slurry away.
The flush water required in all three sealing approaches is provided from an external supply and injected into the process at a better strain than the stuffing field stress, in line with the business standard American Petroleum Institute (API) Piping Plan 32. Water which doesn’t leak onto the bottom or into the process is sent to the tailings dam. This additionally has an effect on the water balance of the plant.
This method constitutes a lack of clear water amounting to billions of gallons a 12 months globally. One massive, conventional slurry pump typically consumes 10 US gallons (37.eight litres) per minute, amounting to 5.2 million US gallons (19.6 million litres) of water yearly – a shocking statistic by any measure.
At a time when global water provide is predicted to fall wanting demand by some 40% by 20301 , removing pointless use of this useful resource should arguably be a central plank of any accountable sustainability programme. Yet excessive water use, and the upper energy consumption it entails, remain embedded within the processes of many mining firms. Worse still, it is truthful to say that it’s typically accepted as simply ‘par for the course’ by reliability engineers and administration alike.
But the fact is that water waste on any scale is a completely unnecessary feature of slurry operations as it can be nearly totally eradicated just by using superior double mechanical seals and modern water administration support systems.
Improve reliability The sort of seal chosen, the setting during which it operates, and crucially, the tank support system which provides the water to maximise seal life, mix to supply the answer to excessive water waste and vitality use.
Modern double mechanical seals have two units of faces, one sealing to the method fluid and one to environment, with a barrier area between the two. They are designed to fulfill the arduous requirements of heavy obligation slurry applications, with fortified steel elements which are highly resistant to corrosion and erosion. Large ports and increased radial clearances imply the lubrication which is vital 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 clear, cool water to the barrier house between the double seals at a pressure greater than the product stress, guaranteeing a constant, steady and clear fluid film to maintain the seal faces cool and lubricated.
As the mechanical seals generate warmth, the new water within the barrier house rises to the tank and is radiated to the ambiance, allowing the cooler, denser water to sink back down to provide cool lubrication to the seal faces. เกจแรงดันน้ำ , the flush water is constantly recycled, flowing across the seal faces in a steady loop and reducing leakage to the absolute minimal, roughly a teaspoonful a day.
While API Plan 32 is unsuitable for servicing a number of slurry pumps in a ‘series train’ with out the necessity to set up special pump methods, pressurised barrier tanks supply ratings as a lot as 435 psi (30 bar), making them perfect for these applications. Self-topping and self-pressurising, they’re additionally almost maintenance-free.
Where no plant water provide is out there for topping up the tank systems, or the availability has inadequate pressure, fluid supply items can be chosen to supply the barrier fluid to seal faces. These have the added advantages of with the ability to supply a water/glycol mixture or oil to provide freeze safety in extremely cold climates.
Wide-ranging benefits The advantages of upgrading to fashionable sealing solutions and help 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 large dilution of product, leading to greatly elevated filtration instances and costs. The pump was sealed with a double mechanical seal designed to satisfy the arduous requirements of the process.
The supporting seal tank system reduced leakage and product dilution to nearly zero. Return on funding was swift and the financial savings long-term. The advantages in phrases of water conservation have been equally longlasting and the company’s status enhanced.
The mining business 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 monetary burden which is completely avoidable.
And when a company can get rid of water waste simultaneously growing reliability and decreasing long term operational costs, the choice to upgrade to fashionable systems ought to surely be a moral imperative as nicely as making sound business sense.