Water waste is commonly deemed an unwanted, however inevitable by-product of mining processes. Yet trendy pump sealing expertise exists which may virtually remove this waste whereas conserving energy, bettering pump reliability and achieving long run operational financial savings.
Water is probably considered one of the most important, and increasingly imperilled, resources on earth. That a lot is understood and acknowledged by industries throughout the globe.
However, additionally it is some of the unnecessarily squandered assets in mining operations. And whereas the trade has begun to embrace efficiency and sustainability-led advances similar to automation and renewable power, it remains 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 identified as ‘dynamic’ seals’) and single mechanical seals. All come with vital limitations, including poor reliability, reduced mean occasions between failure (MTBF), intensive upkeep requirements and better operational prices.
These elements alone should give mine managers cause for a re-evaluation of the sealing methods used on slurry pumps. However, pressure gauge 10 bar with a dedication to the International Standards Organisation ISO-14001 Standard for environmental management systems and ISO-50001 Standard for energy management techniques ought to pay attention to the excessive water waste and high power consumption that results from choosing these traditional sealing methods.
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 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 provide of cool, clean flush water to be injected into the method at high pressure, sustaining a secure 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 external source and injected into the method at a higher stress than the stuffing box strain, according to the trade normal 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 steadiness of the plant.
This strategy constitutes a lack of clean water amounting to billions of gallons a 12 months globally. One large, typical 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 yearly – a shocking statistic by any measure.
At pressure gauge 10 bar when world water supply is predicted to fall in need of demand by some 40% by 20301 , removing unnecessary use of this useful useful resource ought to arguably be a central plank of any responsible sustainability programme. Yet extreme water use, and the higher power consumption it entails, remain embedded in the processes of many mining firms. Worse nonetheless, it’s truthful to say that it’s typically accepted as simply ‘par for the course’ by reliability engineers and management alike.
But the very fact is that water waste on any scale is a totally unnecessary feature of slurry operations as it can be virtually totally eliminated just by using superior double mechanical seals and modern water management support systems.
Improve reliability The kind of seal selected, the setting by which it operates, and crucially, the tank support system which provides the water to maximise seal life, combine to provide the answer to extreme water waste and power use.
Modern double mechanical seals have two units of faces, one sealing to the process fluid and one to environment, with a barrier space between the 2. They are designed to meet the arduous requirements of heavy responsibility slurry purposes, with fortified steel components that are extremely resistant to corrosion and erosion. Large ports and elevated radial clearances mean the lubrication which is vital to optimising seal life is maintained continually 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 house between the double seals at a stress higher than the product strain, ensuring a consistent, secure and clean fluid film to maintain the seal faces cool and lubricated.
As the mechanical seals generate heat, the new water in the barrier space rises to the tank and is radiated to the environment, permitting the cooler, denser water to sink back down to offer cool lubrication to the seal faces. Most importantly, the flush water is continually recycled, flowing throughout the seal faces in a steady 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’ with out the necessity to set up special pump methods, pressurised barrier tanks supply rankings as a lot as 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 supply is out there for topping up the tank methods, or the supply has insufficient strain, fluid supply items may be chosen to produce the barrier fluid to seal faces. These have the added advantages of being ready to provide a water/glycol combination or oil to provide freeze protection in extraordinarily chilly climates.
Wide-ranging benefits The advantages of upgrading to trendy sealing options and assist methods had been felt by a coal mine in Poland utilizing a slurry pump to produce coal mud at 9 bar (135 psi) to filter press. Flushed packing resulted in huge dilution of product, leading to significantly increased filtration times and prices. The pump was sealed with a double mechanical seal designed to satisfy the arduous requirements of the process.
The supporting seal tank system lowered leakage and product dilution to virtually zero. Return on funding was swift and the savings long-term. The advantages in phrases of water conservation have been equally longlasting and the company’s reputation enhanced.
The mining industry should deal with a tough and dear problem when it comes to maintaining 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 remove water waste at the identical time as rising reliability and decreasing long run operational prices, the decision to upgrade to trendy techniques should surely be an ethical imperative as nicely as making sound enterprise sense.
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