Water waste is commonly deemed an undesirable, but inevitable by-product of mining processes. Yet trendy pump sealing know-how exists which can virtually eliminate this waste whereas conserving vitality, bettering pump reliability and achieving long run operational savings.
Water is one of the most significant, and increasingly imperilled, sources on earth. That a lot is understood and acknowledged by industries across the globe.
However, it’s also one of the most unnecessarily squandered assets in mining operations. And whereas the business has begun to embrace effectivity and sustainability-led advances corresponding to automation and renewable vitality, it stays steadfastly set in its ways in relation to slurry pump expertise.
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, including poor reliability, lowered imply instances between failure (MTBF), intensive maintenance necessities and higher operational prices.
These factors alone should give mine managers cause for a re-evaluation of the sealing strategies used on slurry pumps. However, any company with a commitment to the International Standards Organisation ISO-14001 Standard for environmental management techniques and ISO-50001 Standard for vitality management methods should take notice of the excessive water waste and excessive energy consumption that outcomes from choosing 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 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, whereas both single slurry seals and expellers require a supply of cool, clean flush water to be injected into the method at excessive strain, sustaining a stable fluid movie 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 exterior supply and injected into the process at a better strain than the stuffing field stress, consistent with the business commonplace American Petroleum Institute (API) Piping Plan 32. Water which doesn’t leak onto the bottom or into the method is sent to the tailings dam. This also has an impact on the water stability of the plant.
This strategy constitutes a loss of clear water amounting to billions of gallons a year globally. One large, standard slurry pump sometimes 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 stunning statistic by any measure.
At a time when world water supply is predicted to fall short of demand by some 40% by 20301 , eradicating pointless use of this useful resource should arguably be a central plank of any responsible sustainability programme. Yet excessive water use, and the upper vitality consumption it entails, remain embedded within the processes of many mining companies. Worse still, it is fair to say that it is usually accepted as simply ‘par for the course’ by reliability engineers and administration alike.
But the very fact is that water waste on any scale is a completely unnecessary feature of slurry operations as it can be virtually totally eliminated simply by using advanced double mechanical seals and modern water administration help systems.
Improve reliability The type of seal selected, the surroundings during which it operates, and crucially, the tank support system which supplies the water to maximise seal life, combine to provide the answer to excessive water waste and energy use.
Modern double mechanical seals have two sets of faces, one sealing to the process fluid and one to atmosphere, with a barrier area between the two. They are designed to satisfy the arduous necessities of heavy duty slurry applications, with fortified metallic elements that are highly resistant to corrosion and erosion. Large ports and elevated radial clearances mean the lubrication which is significant to optimising seal life is maintained continually and consistently.
A pressurised barrier tank system is central to the environmental sustainability of this resolution. เกจวัดแรงดันแก๊สco2 employs a thermosiphon process which supplies clear, cool water to the barrier house between the double seals at a pressure higher than the product pressure, ensuring a constant, stable and clear fluid movie to maintain the seal faces cool and lubricated.
As the mechanical seals generate warmth, the hot 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 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 lowering leakage to the absolute minimal, roughly a teaspoonful a day.
While API Plan 32 is unsuitable for servicing multiple slurry pumps in a ‘series train’ with out the need to set up particular pump systems, pressurised barrier tanks supply ratings up to 435 psi (30 bar), making them perfect for these purposes. Self-topping and self-pressurising, they’re additionally nearly maintenance-free.
Where no plant water provide is available for topping up the tank systems, or the supply has inadequate pressure, fluid delivery units can be selected to supply the barrier fluid to seal faces. These have the added benefits of with the ability to provide a water/glycol combination or oil to provide freeze safety in extremely cold climates.
Wide-ranging advantages The advantages of upgrading to modern sealing options and assist systems had been 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 large dilution of product, resulting in tremendously increased filtration times and prices. The pump was sealed with a double mechanical seal designed to meet the arduous requirements of the method.
The supporting seal tank system reduced leakage and product dilution to virtually zero. Return on investment 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 industry should take care of a tough and costly problem when it comes to maintaining rotating gear. But the planning, processing and disposal of flush water constitutes an operational and financial burden which is totally avoidable.
And when a company can remove water waste concurrently growing reliability and reducing long run operational prices, the choice to improve to modern methods should surely be a moral imperative as well as making sound business sense.
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