Water waste is usually deemed an undesirable, but inevitable by-product of mining processes. Yet fashionable pump sealing technology exists which can nearly get rid of this waste while conserving vitality, improving pump reliability and achieving long term operational financial savings.
Water is certainly one of the most vital, and more and more imperilled, assets on earth. That much is known and acknowledged by industries across the globe.
However, it’s also one of the most unnecessarily squandered sources in mining operations. And while the business has begun to embrace efficiency and sustainability-led advances corresponding to automation and renewable vitality, it remains steadfastly set in its methods when it comes to slurry pump expertise.
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, including poor reliability, decreased imply times between failure (MTBF), intensive upkeep requirements and higher operational costs.
These components alone should give mine managers trigger for a re-evaluation of the sealing methods used on slurry pumps. However, any firm with a dedication to the International Standards Organisation ISO-14001 Standard for environmental management systems and ISO-50001 Standard for power management techniques should pay consideration to the extreme water waste and high vitality consumption that outcomes from choosing 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 wasteful aspects of slurry processing which is seal flush water injection.
On gland packed pumps it’s important that packing is flushed with clear water to keep it cool and lubricated, whereas both single slurry seals and expellers require a supply of cool, clear flush water to be injected into the process at excessive pressure, maintaining a secure fluid movie between the fragile 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 external supply and injected into the method at a higher stress than the stuffing box stress, in line with the trade normal 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 impact on the water stability of the plant.
This method constitutes a lack of clean water amounting to billions of gallons a yr globally. One giant, conventional slurry pump sometimes consumes 10 US gallons (37.eight litres) per minute, amounting to 5.2 million US gallons (19.6 million litres) of water every year – a surprising statistic by any measure.
At a time when world water supply is predicted to fall wanting demand by some 40% by 20301 , eradicating pointless use of this priceless resource should arguably be a central plank of any accountable sustainability programme. Yet excessive water use, and the upper energy consumption it entails, stay embedded within the processes of many mining firms. Worse nonetheless, it’s fair 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 very pointless characteristic of slurry operations as it can be almost completely eradicated simply by employing superior double mechanical seals and fashionable water management assist techniques.
Improve reliability The kind of seal chosen, the surroundings in which it operates, and crucially, the tank assist system which supplies the water to maximise seal life, mix to offer the solution to extreme water waste and vitality use.
Modern double mechanical seals have two sets of faces, one sealing to the method fluid and one to ambiance, with a barrier space between the two. They are designed to fulfill the arduous necessities of heavy responsibility slurry applications, with fortified metal components which are highly resistant to corrosion and erosion. Large ports and increased radial clearances imply the lubrication which is vital to optimising seal life is maintained continually and constantly.
A pressurised barrier tank system is central to the environmental sustainability of this answer. It employs a thermosiphon process which provides clear, cool water to the barrier area between the double seals at a strain higher than the product stress, guaranteeing a consistent, stable and clean fluid film to keep the seal faces cool and lubricated.
As the mechanical seals generate heat, the recent water within the barrier space rises to the tank and is radiated to the environment, allowing the cooler, denser water to sink again down to provide cool lubrication to the seal faces. Most importantly, the flush water is continually recycled, flowing across the seal faces in a steady loop and decreasing 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’ with out the want to set up particular pump techniques, pressurised barrier tanks provide rankings as much as 435 psi (30 bar), making them best for these purposes. Self-topping and self-pressurising, they’re additionally nearly maintenance-free.
Where no plant water supply is on the market for topping up the tank methods, or the availability has insufficient stress, fluid supply items can be selected to produce the barrier fluid to seal faces. These have the added advantages of being able to supply a water/glycol mixture or oil to offer freeze protection in extraordinarily cold climates.
Wide-ranging benefits The benefits of upgrading to modern sealing options and support techniques 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 big dilution of product, resulting in tremendously elevated filtration times and costs. 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 just about zero. Return on funding was swift and the financial savings long-term. pressure gauge หน้าปัด 4 นิ้ว when it comes to water conservation have been equally longlasting and the company’s reputation enhanced.
The mining industry should take care of a tricky and dear problem in relation to sustaining rotating gear. But the planning, processing and disposal of flush water constitutes an operational and monetary burden which is totally avoidable.
And when an organization can remove water waste at the identical time as increasing reliability and reducing long term operational costs, the choice to improve to trendy systems should surely be an ethical imperative as well as making sound enterprise sense.
Share