Water waste is commonly deemed an undesirable, but inevitable by-product of mining processes. Yet modern pump sealing know-how exists which may virtually remove this waste while conserving power, improving pump reliability and reaching long term operational savings.
Water is likely considered one of the most important, and more and more imperilled, sources on earth. That a lot is known and acknowledged by industries across the globe.
However, additionally it is one of the most unnecessarily squandered sources in mining operations. And whereas the industry has begun to embrace effectivity and sustainability-led advances such as automation and renewable vitality, it remains steadfastly set in its ways in phrases of slurry pump expertise.
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 important limitations, together with poor reliability, decreased imply occasions between failure (MTBF), intensive upkeep requirements and better operational costs.
These elements alone ought to give mine managers trigger 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 administration methods and ISO-50001 Standard for vitality administration systems ought to pay attention to the extreme water waste and excessive power consumption that outcomes from choosing these conventional sealing methods.
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 aspects of slurry processing which is seal flush water injection.
On gland packed pumps it’s essential that packing is flushed with clear water to keep it cool and lubricated, whereas each single slurry seals and expellers require a provide of cool, clear flush water to be injected into the process at high pressure, sustaining a stable fluid movie between the delicate seal faces to maintain them cool and lubricated, while forcing the damaging slurry away.
เกจวัดแรงดันแก๊สlpg required in all three sealing approaches is equipped from an exterior source and injected into the process at the next pressure than the stuffing field stress, in line with the trade standard American Petroleum Institute (API) Piping Plan 32. Water which doesn’t leak onto the ground or into the process is shipped to the tailings dam. This also has an effect 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 usually 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 surprising statistic by any measure.
At a time when global water supply is predicted to fall in want of demand by some 40% by 20301 , removing unnecessary use of this valuable resource ought to arguably be a central plank of any responsible sustainability programme. Yet excessive water use, and the upper power consumption it entails, stay embedded within the processes of many mining firms. Worse still, it’s honest to say that it’s typically accepted as merely ‘par for the course’ by reliability engineers and administration alike.
But the fact is that water waste on any scale is a very unnecessary characteristic of slurry operations as it can be almost totally eliminated just by using superior double mechanical seals and trendy water administration help techniques.
Improve reliability The sort of seal chosen, the environment in which it operates, and crucially, the tank support system which supplies the water to maximise seal life, combine to offer the answer to excessive water waste and vitality use.
Modern double mechanical seals have two units of faces, one sealing to the process fluid and one to ambiance, with a barrier area between the 2. They are designed to meet the arduous necessities of heavy duty slurry purposes, with fortified steel components that are extremely immune to corrosion and erosion. Large ports and increased radial clearances imply the lubrication which is vital 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 course of which supplies clear, cool water to the barrier house between the double seals at a strain larger than the product stress, guaranteeing a consistent, steady and clear fluid film to keep the seal faces cool and lubricated.
As the mechanical seals generate heat, the recent water in the barrier area 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 lowering 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’ with out the need to set up particular pump methods, pressurised barrier tanks supply ratings as a lot as 435 psi (30 bar), making them best for these functions. Self-topping and self-pressurising, they are also almost maintenance-free.
Where no plant water provide is out there for topping up the tank techniques, or the availability has inadequate strain, fluid delivery units could be chosen to provide the barrier fluid to seal faces. These have the added benefits of being able to supply a water/glycol combination or oil to provide freeze protection in extremely cold climates.
Wide-ranging advantages The benefits of upgrading to modern sealing solutions 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 occasions and costs. The pump was sealed with a double mechanical seal designed to meet the arduous necessities 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. The benefits in terms of water conservation have been equally longlasting and the company’s status enhanced.
The mining business should take care of a tricky and dear challenge in relation to sustaining rotating tools. But the planning, processing and disposal of flush water constitutes an operational and financial burden which is entirely avoidable.
And when a company can eliminate water waste at the identical time as increasing reliability and reducing long term operational costs, the decision to upgrade to modern systems ought to surely be a moral imperative as nicely as making sound business sense.