Water waste is usually deemed an undesirable, but inevitable by-product of mining processes. Yet fashionable pump sealing expertise exists which may virtually remove this waste while conserving vitality, enhancing pump reliability and achieving long run operational financial savings.
Water is one of the most important, and more and more imperilled, assets on earth. That much is understood and acknowledged by industries across the globe.
However, it’s also one of the 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 stays 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 generally known as ‘dynamic’ seals’) and single mechanical seals. All come with vital limitations, together with poor reliability, reduced imply times between failure (MTBF), intensive maintenance necessities and higher operational prices.
These components alone should give mine managers cause for a re-evaluation of the sealing strategies used on slurry pumps. However, any firm with a commitment to the International Standards Organisation ISO-14001 Standard for environmental management techniques and ISO-50001 Standard for energy administration systems ought to pay attention to the excessive water waste and high power 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 one of the most wasteful features of slurry processing which is seal flush water injection.
On gland packed pumps it’s important that packing is flushed with clean water to maintain it cool and lubricated, while each single slurry seals and expellers require a supply of cool, clear flush water to be injected into the method at high strain, maintaining a steady 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 process at a better pressure than the stuffing box stress, according to the trade commonplace 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.
เกจวัดแรงดันออกซิเจน constitutes a loss of clear water amounting to billions of gallons a yr globally. One massive, standard slurry pump sometimes consumes 10 US gallons (37.8 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 international water supply is predicted to fall wanting demand by some 40% by 20301 , eradicating pointless use of this priceless useful resource should arguably be a central plank of any responsible sustainability programme. Yet extreme water use, and the upper power consumption it entails, stay embedded in the processes of many mining companies. Worse still, it is fair to say that it’s often accepted as merely ‘par for the course’ by reliability engineers and management alike.
But the precise fact is that water waste on any scale is a completely unnecessary function of slurry operations as it can be nearly totally eliminated just by using advanced double mechanical seals and fashionable water administration support systems.
Improve reliability The type 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 supply the solution to excessive water waste and power use.
Modern double mechanical seals have two units of faces, one sealing to the process fluid and one to ambiance, with a barrier house between the 2. They are designed to meet the arduous necessities of heavy obligation slurry purposes, with fortified steel components which are highly proof against corrosion and erosion. Large ports and increased radial clearances imply the lubrication which is significant to optimising seal life is maintained constantly and consistently.
A pressurised barrier tank system is central to the environmental sustainability of this answer. It employs a thermosiphon process which supplies clear, cool water to the barrier space between the double seals at a pressure higher than the product pressure, making certain a constant, steady and clear fluid movie to maintain the seal faces cool and lubricated.
As the mechanical seals generate heat, the recent water within the barrier house rises to the tank and is radiated to the atmosphere, allowing the cooler, denser water to sink back down to supply cool lubrication to the seal faces. Most importantly, the flush water is continually recycled, flowing across 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 need to set up special pump systems, pressurised barrier tanks offer ratings up to 435 psi (30 bar), making them best for these purposes. Self-topping and self-pressurising, they’re also nearly maintenance-free.
Where no plant water provide is out there for topping up the tank techniques, or the availability has inadequate strain, fluid supply models could be chosen to provide the barrier fluid to seal faces. These have the added benefits of having the ability to provide a water/glycol combination or oil to provide freeze safety in extremely chilly climates.
Wide-ranging benefits The benefits of upgrading to trendy sealing solutions and assist methods were felt by a coal mine in Poland utilizing a slurry pump to supply coal mud at 9 bar (135 psi) to filter press. Flushed packing resulted in huge dilution of product, resulting in significantly increased filtration instances and prices. The pump was sealed with a double mechanical seal designed to meet the arduous requirements of the process.
The supporting seal tank system decreased leakage and product dilution to nearly zero. Return on funding was swift and the financial savings long-term. The advantages by method of water conservation have been equally longlasting and the company’s popularity enhanced.
The mining industry should deal with a troublesome and costly challenge in terms of sustaining rotating equipment. But the planning, processing and disposal of flush water constitutes an operational and financial burden which is completely avoidable.
And when an organization can remove water waste simultaneously increasing reliability and reducing long term operational prices, the choice to upgrade to trendy systems ought to absolutely be an ethical imperative as properly as making sound enterprise sense.
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