Water waste is commonly deemed an unwanted, but inevitable by-product of mining processes. Yet modern pump sealing know-how exists which may nearly get rid of this waste while conserving vitality, enhancing pump reliability and reaching long term operational financial savings.
Water is certainly 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, additionally it is some of the unnecessarily squandered resources in mining operations. And while the industry has begun to embrace effectivity and sustainability-led advances similar to automation and renewable energy, 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 generally known as ‘dynamic’ seals’) and single mechanical seals. All come with significant limitations, including poor reliability, reduced imply occasions between failure (MTBF), intensive upkeep necessities and better operational prices.
These components alone should give mine managers trigger for a re-evaluation of the sealing methods used on slurry pumps. However, any company with a commitment to the International Standards Organisation ISO-14001 Standard for environmental management systems and ISO-50001 Standard for power administration methods should take observe of the excessive water waste and high power consumption that outcomes 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 one of the wasteful features of slurry processing which is seal flush water injection.
On gland packed pumps it’s essential that packing is flushed with clean water to maintain it cool and lubricated, while both single slurry seals and expellers require a supply of cool, clean flush water to be injected into the method at excessive pressure, sustaining a stable 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 source and injected into the process at a better stress than the stuffing field strain, in line with the industry commonplace 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 also has an effect on the water stability of the plant.
This method constitutes a loss of clear water amounting to billions of gallons a 12 months globally. One giant, conventional slurry pump sometimes consumes 10 US gallons (37.eight litres) per minute, amounting to 5.2 million US gallons (19.6 million litres) of water every year – a shocking statistic by any measure.
At a time when international water supply is predicted to fall wanting demand by some 40% by 20301 , removing pointless use of this valuable useful resource ought to arguably be a central plank of any responsible sustainability programme. Yet extreme water use, and the upper energy consumption it entails, stay embedded within the processes of many mining firms. Worse still, it is truthful to say that it’s usually 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 very pointless feature of slurry operations as it could be nearly completely eliminated just by using advanced double mechanical seals and modern water administration support systems.
Improve reliability The kind of seal chosen, the setting by which it operates, and crucially, the tank support system which provides the water to maximise seal life, combine to supply the solution to excessive water waste and power use.
Modern double mechanical seals have two sets of faces, one sealing to the process fluid and one to ambiance, with a barrier house between the two. They are designed to meet the arduous necessities of heavy obligation slurry purposes, with fortified steel components which are extremely proof against corrosion and erosion. Large ports and elevated radial clearances imply the lubrication which is important to optimising seal life is maintained continually and consistently.
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, ensuring a consistent, steady and clean fluid film to maintain the seal faces cool and lubricated.
As the mechanical seals generate warmth, the new water in the barrier house rises to the tank and is radiated to the ambiance, allowing the cooler, denser water to sink again down to supply cool lubrication to the seal faces. Most importantly, the flush water is constantly recycled, flowing throughout the seal faces in a continuous loop and decreasing leakage to absolutely the minimal, roughly a teaspoonful a day.
While API Plan 32 is unsuitable for servicing a number of slurry pumps in a ‘series train’ without the necessity to set up particular pump systems, pressurised barrier tanks offer rankings as a lot as 435 psi (30 bar), making them ideal for these functions. Self-topping and self-pressurising, they are also almost maintenance-free.
Where no plant water provide is on the market for topping up the tank techniques, or the provision has insufficient strain, fluid supply models could be selected to provide the barrier fluid to seal faces. These have the added benefits of with the ability to provide a water/glycol mixture or oil to supply freeze safety in extremely cold climates.
Wide-ranging advantages The advantages of upgrading to modern sealing solutions and support systems had been felt by a coal mine in Poland utilizing a slurry pump to provide coal mud at 9 bar (135 psi) to filter press. Flushed packing resulted in big dilution of product, resulting in greatly increased filtration times and prices. The pump was sealed with a double mechanical seal designed to fulfill the arduous requirements of the process.
The supporting seal tank system reduced leakage and product dilution to virtually zero. Return on ชนิดของpressuregauge was swift and the savings long-term. The benefits when it comes to water conservation have been equally longlasting and the company’s status enhanced.
The mining business should take care of a tough and dear challenge in relation to sustaining rotating equipment. But the planning, processing and disposal of flush water constitutes an operational and monetary burden which is entirely avoidable.
And when an organization can get rid of water waste concurrently growing reliability and reducing long run operational prices, the decision to upgrade to trendy techniques should certainly be a moral crucial as properly as making sound enterprise sense.
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