Less waste means more reliability

Water waste is commonly deemed an unwanted, but inevitable by-product of mining processes. Yet fashionable pump sealing know-how exists which might nearly eliminate this waste while conserving vitality, bettering pump reliability and achieving long term operational financial savings.
Water is one of the most vital, and more and more imperilled, sources on earth. That much is understood and acknowledged by industries across the globe.
However, it’s also some of the unnecessarily squandered assets in mining operations. And whereas the trade has begun to embrace effectivity and sustainability-led advances similar to automation and renewable energy, it stays steadfastly set in its ways when it comes to slurry pump technology.
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 important limitations, together with poor reliability, lowered imply occasions between failure (MTBF), intensive maintenance requirements and better operational prices.
These components alone ought to give mine managers trigger for a re-evaluation of the sealing methods used on slurry pumps. However, any firm with a commitment to the International Standards Organisation ISO-14001 Standard for environmental management systems and ISO-50001 Standard for vitality administration techniques ought to take note of the excessive water waste and excessive vitality consumption that results from opting for these traditional 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 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 clear water to maintain 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 strain, sustaining 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 equipped from an exterior source and injected into the process at a higher pressure than the stuffing box stress, according to the industry normal American Petroleum Institute (API) Piping Plan 32. Water which doesn’t leak onto the ground or into the method is sent to the tailings dam. This also has an impact on the water balance of the plant.
This approach constitutes a lack of clear water amounting to billions of gallons a 12 months globally. One large, 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 every year – a surprising statistic by any measure.
At a time when global water supply is predicted to fall in need of demand by some 40% by 20301 , eradicating pointless use of this useful useful resource ought to 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 companies. Worse nonetheless, it’s honest to say that it’s usually accepted as merely ‘par for the course’ by reliability engineers and management alike.
But the fact is that water waste on any scale is a very unnecessary characteristic of slurry operations as it can be virtually completely eliminated simply by employing advanced double mechanical seals and trendy water management assist systems.
Improve reliability The kind of seal chosen, the setting in which it operates, and crucially, the tank help system which provides the water to maximise seal life, mix to provide the answer to extreme water waste and power use.
Modern double mechanical seals have two sets of faces, one sealing to the method fluid and one to atmosphere, with a barrier space between the two. They are designed to satisfy the arduous necessities of heavy duty slurry purposes, with fortified steel components which are highly immune to corrosion and erosion. Large ports and elevated radial clearances mean the lubrication which is significant to optimising seal life is maintained constantly and constantly.
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 house between the double seals at a strain higher than the product pressure, ensuring a consistent, steady and clean fluid film to keep the seal faces cool and lubricated.
As the mechanical seals generate warmth, the new water in the barrier space rises to the tank and is radiated to the environment, permitting the cooler, denser water to sink again down to offer cool lubrication to the seal faces. spmk700 , the flush water is constantly recycled, flowing across the seal faces in a steady loop and lowering leakage to the absolute minimum, roughly a teaspoonful a day.
While API Plan 32 is unsuitable for servicing multiple slurry pumps in a ‘series train’ without the need to install particular pump techniques, pressurised barrier tanks supply rankings up to 435 psi (30 bar), making them best for these functions. Self-topping and self-pressurising, they are additionally nearly maintenance-free.
Where no plant water supply is available for topping up the tank techniques, or the supply has insufficient stress, fluid supply units may be selected to produce the barrier fluid to seal faces. These have the added benefits of having the flexibility to supply a water/glycol mixture or oil to offer freeze safety in extremely cold climates.
Wide-ranging advantages The benefits of upgrading to modern sealing options and support systems were felt by a coal mine in Poland using a slurry pump to provide coal mud at 9 bar (135 psi) to filter press. Flushed packing resulted in large dilution of product, resulting in greatly elevated filtration occasions and prices. The pump was sealed with a double mechanical seal designed to satisfy the arduous necessities of the process.
The supporting seal tank system reduced leakage and product dilution to virtually zero. Return on funding 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 cope with a tough and expensive challenge in phrases of sustaining rotating gear. But the planning, processing and disposal of flush water constitutes an operational and financial burden which is completely avoidable.
And when a company can remove water waste concurrently growing reliability and reducing long term operational costs, the decision to upgrade to trendy systems ought to absolutely be an ethical imperative as well as making sound enterprise sense.
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