Water waste is often deemed an unwanted, however inevitable by-product of mining processes. Yet trendy pump sealing technology exists which might virtually eliminate this waste while conserving vitality, enhancing pump reliability and reaching long term operational savings.
Water is among the most important, and more and more imperilled, sources on earth. That much is understood and acknowledged by industries throughout the globe.
However, it is also some of the unnecessarily squandered sources in mining operations. And while the business has begun to embrace efficiency and sustainability-led advances similar to automation and renewable energy, it remains steadfastly set in its methods when it comes to slurry pump technology.
Three approaches are routinely specified by pump producers to seal slurry pumps: mechanical packing, expellers (also generally recognized as ‘dynamic’ seals’) and single mechanical seals. All come with significant limitations, including poor reliability, reduced mean occasions between failure (MTBF), intensive upkeep requirements and better operational prices.
These factors alone should give mine managers trigger for a re-evaluation of the sealing strategies used on slurry pumps. However, any firm with a dedication to the International Standards Organisation ISO-14001 Standard for environmental administration methods and ISO-50001 Standard for vitality management methods ought to pay consideration to the extreme water waste and high vitality consumption that results from choosing these traditional 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 some of the wasteful aspects 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 provide of cool, clean flush water to be injected into the process at excessive pressure, sustaining a steady fluid movie between the delicate seal faces to maintain them cool and lubricated, whereas forcing the damaging slurry away.
The flush water required in all three sealing approaches is provided from an exterior supply and injected into the process at a higher pressure than the stuffing field stress, in line with the trade normal American Petroleum Institute (API) Piping Plan 32. Water which doesn’t leak onto the bottom or into the process is distributed to the tailings dam. This also has an effect on the water balance of the plant.
This approach constitutes a lack of clear water amounting to billions of gallons a year globally. One giant, conventional slurry pump typically consumes 10 US gallons (37.8 litres) per minute, amounting to 5.2 million US gallons (19.6 million litres) of water yearly – a surprising statistic by any measure.
At a time when global water supply is predicted to fall wanting demand by some 40% by 20301 , removing pointless use of this valuable 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 in the processes of many mining firms. Worse nonetheless, it’s truthful to say that it’s usually accepted as merely ‘par for the course’ by reliability engineers and administration alike.
But the very fact is that water waste on any scale is a totally pointless feature of slurry operations as it can be nearly totally eliminated just by employing advanced double mechanical seals and modern water administration support methods.
Improve reliability The sort of seal selected, the surroundings by which it operates, and crucially, the tank support system which provides the water to maximise seal life, mix to offer the answer to extreme water waste and vitality use.
Modern double mechanical seals have two units of faces, one sealing to the method fluid and one to ambiance, with a barrier area between the 2. They are designed to meet the arduous requirements of heavy obligation slurry purposes, with fortified metallic elements which are extremely immune to corrosion and erosion. Large ports and elevated radial clearances imply the lubrication which is significant to optimising seal life is maintained continually and persistently.
A pressurised barrier tank system is central to the environmental sustainability of this solution. It employs a thermosiphon process which supplies clear, cool water to the barrier house between the double seals at a strain higher than the product strain, guaranteeing a constant, stable and clear fluid movie to keep the seal faces cool and lubricated.
As the mechanical seals generate warmth, the recent water in the barrier area rises to the tank and is radiated to the atmosphere, permitting the cooler, denser water to sink back down to supply cool lubrication to the seal faces. spmk700 , the flush water is constantly recycled, flowing throughout the seal faces in a continuous loop and reducing leakage to the absolute minimum, roughly a teaspoonful a day.
While API Plan 32 is unsuitable for servicing a number of slurry pumps in a ‘series train’ with out the necessity to set up particular pump techniques, pressurised barrier tanks supply rankings up to 435 psi (30 bar), making them best for these purposes. Self-topping and self-pressurising, they’re additionally almost maintenance-free.
Where no plant water provide is available for topping up the tank methods, or the availability has inadequate stress, fluid supply models could be selected to provide the barrier fluid to seal faces. These have the added advantages of being in a position to supply a water/glycol mixture or oil to provide freeze protection in extremely chilly climates.
Wide-ranging advantages The benefits of upgrading to modern sealing options and help techniques 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 large dilution of product, resulting in greatly elevated filtration times and prices. The pump was sealed with a double mechanical seal designed to meet the arduous necessities of the process.
The supporting seal tank system decreased leakage and product dilution to nearly zero. Return on investment was swift and the financial savings long-term. The benefits by means of water conservation have been equally longlasting and the company’s popularity enhanced.
The mining business must deal with a tough and dear problem in relation to maintaining rotating equipment. But the planning, processing and disposal of flush water constitutes an operational and financial burden which is totally avoidable.
And when an organization can eliminate water waste at the identical time as increasing reliability and reducing long term operational costs, the decision to improve to trendy systems ought to absolutely be a moral crucial in addition to making sound enterprise sense.