Water waste is commonly deemed an unwanted, but inevitable by-product of mining processes. Yet modern pump sealing expertise exists which may virtually remove this waste while conserving power, bettering pump reliability and achieving long term operational savings.
Water is doubtless certainly one of the most important, and more and more imperilled, resources on earth. That a lot is understood and acknowledged by industries across the globe.
However, additionally it is one of the most unnecessarily squandered sources in mining operations. And whereas the business has begun to embrace efficiency and sustainability-led advances similar to automation and renewable energy, it remains steadfastly set in its methods in terms of slurry pump know-how.
Three approaches are routinely specified by pump producers to seal slurry pumps: mechanical packing, expellers (also known as ‘dynamic’ seals’) and single mechanical seals. All come with vital limitations, including poor reliability, decreased mean times between failure (MTBF), intensive upkeep requirements and better operational costs.
These factors alone ought to give mine managers trigger for a re-evaluation of the sealing strategies used on slurry pumps. However, any company with a dedication to the International Standards Organisation ISO-14001 Standard for environmental management systems and ISO-50001 Standard for power management systems should take observe of the extreme water waste and high energy consumption that results from opting for these conventional sealing strategies.
Inefficient sealing When used to seal the process pumps in a mine’s scrubber and floatation circuits, gland packing, single mechanical seals and expeller seals all demand some of the wasteful aspects of slurry processing which is seal flush water injection.
On gland packed pumps it’s essential that packing is flushed with clear water to maintain it cool and lubricated, whereas both single slurry seals and expellers require a provide of cool, clean flush water to be injected into the process at high stress, maintaining a stable fluid movie between the fragile seal faces to keep 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 method at the next pressure than the stuffing box strain, in line with the trade commonplace American Petroleum Institute (API) Piping Plan 32. Water which doesn’t leak onto the bottom or into the method is shipped to the tailings dam. This additionally has an impact on the water balance of the plant.
This strategy constitutes a lack of clear water amounting to billions of gallons a yr globally. One giant, standard slurry pump sometimes consumes 10 US gallons (37.8 litres) per minute, amounting to 5.2 million US gallons (19.6 million litres) of water every year – a stunning statistic by any measure.
At a time when international water provide is predicted to fall wanting demand by some 40% by 20301 , removing pointless use of this valuable resource ought to arguably be a central plank of any responsible sustainability programme. Yet เครื่องมือที่ใช้วัดความดันคือ , and the higher energy consumption it entails, stay embedded within the processes of many mining corporations. Worse still, it’s fair to say that it’s typically accepted as simply ‘par for the course’ by reliability engineers and management alike.
But the very fact is that water waste on any scale is a very pointless feature of slurry operations as it can be virtually totally eliminated simply by employing advanced double mechanical seals and fashionable water administration help techniques.
Improve reliability The kind of seal chosen, the surroundings during which it operates, and crucially, the tank help system which supplies the water to maximise seal life, combine to offer the solution to extreme water waste and vitality use.
Modern double mechanical seals have two units of faces, one sealing to the process fluid and one to atmosphere, with a barrier space between the two. They are designed to meet the arduous requirements of heavy duty slurry applications, with fortified metal parts that are extremely proof against corrosion and erosion. Large ports and increased radial clearances imply 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 course of which provides clear, cool water to the barrier area between the double seals at a strain 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 recent water in the barrier house rises to the tank and is radiated to the environment, permitting the cooler, denser water to sink back down to provide cool lubrication to the seal faces. Most importantly, the flush water is consistently recycled, flowing throughout the seal faces in a continuous loop and reducing 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’ without the necessity to install special pump methods, pressurised barrier tanks supply rankings as a lot as 435 psi (30 bar), making them perfect for these applications. Self-topping and self-pressurising, they are additionally almost maintenance-free.
Where no plant water supply is on the market for topping up the tank systems, or the supply has insufficient pressure, fluid delivery items may be selected to provide the barrier fluid to seal faces. These have the added advantages of being in a position to supply a water/glycol combination or oil to offer freeze protection in extremely chilly climates.
Wide-ranging advantages The advantages of upgrading to modern sealing options and support 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 times and prices. The pump was sealed with a double mechanical seal designed to fulfill the arduous requirements of the method.
The supporting seal tank system lowered leakage and product dilution to nearly zero. Return on investment was swift and the financial savings long-term. The benefits by means of water conservation have been equally longlasting and the company’s reputation enhanced.
The mining business should deal with a tough and expensive problem in relation to maintaining rotating tools. But the planning, processing and disposal of flush water constitutes an operational and financial burden which is completely avoidable.
And when a company can get rid of water waste concurrently rising reliability and reducing long run operational prices, the decision to upgrade to fashionable systems ought to certainly be an ethical imperative as well as making sound enterprise sense.
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