Water waste is often deemed an undesirable, however inevitable by-product of mining processes. Yet trendy pump sealing technology exists which may nearly get rid of this waste while conserving power, enhancing pump reliability and attaining long term operational savings.
Water is likely certainly one of the most significant, and increasingly imperilled, assets on earth. That much is understood and acknowledged by industries across the globe.
However, additionally it is one of the most unnecessarily squandered assets in mining operations. And while the business has begun to embrace effectivity and sustainability-led advances corresponding to automation and renewable energy, it remains steadfastly set in its methods in relation to slurry pump know-how.
Three approaches are routinely specified by pump producers to seal slurry pumps: mechanical packing, expellers (also often known as ‘dynamic’ seals’) and single mechanical seals. All include important limitations, together with poor reliability, lowered imply instances between failure (MTBF), intensive maintenance requirements and higher operational prices.
These elements alone should 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 techniques and ISO-50001 Standard for energy management techniques ought to pay attention to the excessive water waste and high vitality consumption that outcomes from opting for these traditional sealing methods.
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 elements 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, whereas each single slurry seals and expellers require a supply of cool, clear flush water to be injected into the process at excessive pressure, maintaining a steady fluid film between the delicate seal faces to maintain them cool and lubricated, while forcing the damaging slurry away.
The flush water required in all three sealing approaches is equipped from an external supply and injected into the process at a better pressure than the stuffing box strain, consistent with the trade normal American Petroleum Institute (API) Piping Plan 32. Water which doesn’t leak onto the ground or into the process is sent to the tailings dam. This also has an effect on the water balance of the plant.
This strategy constitutes a loss of clear water amounting to billions of gallons a year globally. One massive, typical slurry pump typically consumes 10 US gallons (37.eight litres) per minute, amounting to five.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 wanting demand by some 40% by 20301 , removing pointless use of this useful resource ought to arguably be a central plank of any accountable sustainability programme. Yet extreme water use, and the upper energy consumption it entails, stay embedded within the processes of many mining corporations. Worse still, it is truthful to say that it’s typically accepted as merely ‘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 characteristic of slurry operations as it can be virtually completely eradicated simply by employing superior double mechanical seals and modern water management assist systems.
Improve reliability The sort of seal selected, the setting in which it operates, and crucially, the tank help system which provides the water to maximise seal life, combine to supply the solution to excessive water waste and vitality use.
Modern double mechanical seals have two sets of faces, one sealing to the process fluid and one to ambiance, with a barrier area between the 2. They are designed to meet the arduous necessities of heavy duty slurry purposes, with fortified steel components which are highly immune to corrosion and erosion. Large ports and increased radial clearances imply the lubrication which is important to optimising seal life is maintained continuously and persistently.
A pressurised barrier tank system is central to the environmental sustainability of this solution. It employs a thermosiphon process which provides clear, cool water to the barrier area between the double seals at a pressure higher than the product strain, guaranteeing a consistent, secure and clean fluid movie to maintain the seal faces cool and lubricated.
As the mechanical seals generate warmth, the recent water in the barrier space rises to the tank and is radiated to the ambiance, permitting the cooler, denser water to sink back down to provide cool lubrication to the seal faces. Most importantly, the flush water is constantly recycled, flowing across the seal faces in a continuous loop and reducing leakage to absolutely the 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 set up special pump techniques, pressurised barrier tanks provide rankings as a lot as 435 psi (30 bar), making them ideal for these functions. Self-topping and self-pressurising, they’re additionally virtually maintenance-free.
Where no plant water provide is out there for topping up the tank systems, or the availability has inadequate pressure, fluid delivery units can be selected to produce the barrier fluid to seal faces. These have the added advantages of having the ability to provide a water/glycol mixture or oil to supply freeze protection in extremely chilly climates.
เกจ์วัดความดัน -ranging benefits The advantages of upgrading to fashionable sealing solutions and support methods had been 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, resulting in significantly elevated filtration times and costs. The pump was sealed with a double mechanical seal designed to satisfy the arduous necessities of the process.
The supporting seal tank system lowered leakage and product dilution to just about zero. Return on investment was swift and the financial savings long-term. The benefits when it comes to water conservation have been equally longlasting and the company’s status enhanced.
The mining industry should cope with a tricky and expensive challenge in relation to maintaining rotating tools. But the planning, processing and disposal of flush water constitutes an operational and monetary burden which is completely avoidable.
And when an organization can eliminate water waste simultaneously increasing reliability and decreasing long term operational costs, the decision to improve to trendy methods ought to certainly be a moral imperative as well as making sound enterprise sense.
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