"Pigging" In Hygienic and Liquid Processes, Production and Manufacturing
Peter Elgar
Exec Chairman at HPS - Advanced Liquid Product Recovery (Pigging) Technology for Companies that Process Liquids. HPS Systems Significantly Increase Yields, Efficiency & Sustainability while Reducing Waste, Water & Energy
HERE’S A VIDEO OF A ‘PIG’ TRAVELLING THROUGH A PIPELINE
It’s not often you get to see a pig travelling through a pipeline. However, here’s a video I took on my phone recently.
The video is on a test and research rig that the HPS R&D team are working on.
The rig has a sight glass which gives us the rare opportunity to see a pig travelling through a section of line.
A Recap on Pigging
If you’re not sure what a ‘pig’ or ‘pigging’ is, well, firstly pigging is a term for what’s better described as “Liquid product recovery”.
Liquid product recovery (pigging) systems save companies that pump, transfer, manufacture or process liquids tens, often hundreds of thousands of Dollars, Pounds or Euros every year.
They do this by recovering the product that remains in pipelines, which would otherwise be wasted (usually as effluent).
As well as saving money through increased yields, greater capacity, waste reduction and associated savings on waste treatment costs, pigging systems also speed up batch changeover times, reduce the use of water, energy, CiP chemicals, help create less effluent plus lower contamination and cross-contamination risks.
What’s more, they do all this while improving environmental sustainability.
That’s why HPS Product Recovery Solutions pigging technology is in wide use in manufacturing food, beverages, confectionery, pet food, paints, coatings, chemicals, industrial lubricants, household, cosmetics and personal care products, and many other the items.
Where is Pigging Used?
There are simply too many products to list that HPS pigging systems are used in the manufacture of. ?However, some examples include ready meals, soups, sauces and dips, wines, spirits, sodas, beers, juices, sports drinks and other beverages, dog and cat foods, meat slurries, hand lotions, toothpaste, personal care creams, soaps, shampoos, shower gels, paints and coatings, specialist chemicals, solvents, industrial lubricants, adhesives, and just about any other liquid you can pump through a pipeline!
If it wasn’t for pigging, many of these products would probably be a lot more expensive to us, as consumers, due to the operational efficiency gains and waste reduction that pigging delivers.
When Is Pigging Used?
Pigging is usually performed prior to the cleaning or CiP process to recover nearly all the product in the line. ?
The recovered product is perfectly usable, it’s in exactly the same condition as the rest of the product, and is usually delivered to the same destination where it is stored, packaged or continues to the next stage of the process.
As well as saving lots of product, because there is virtually no product left in the line, pigging ?makes the rinsing, cleaning and sanitisation cycles much quicker and less resource intensive.
For example, rinsing and flushes are usually much shorter and this is often where the large savings in water, energy and CiP fluids come in.
If you look at the video, you’ll see it’s showing a pig (the blue projectile) travelling vertically through a pipeline.
The pig is being propelled by water and is recovering (pushing) a fairly viscous white product through a 3-inch diameter line.
The pig is near the start of its journey and pushing a full pipeline’s worth of product that’s ahead of it. The pipeline is around 35 metres long.
How Are Pigs Propelled?
Most commonly, pigs are propelled by filtered compressed air.
Sometimes they are propelled by other gases such as carbon dioxide or nitrogen.
Occasionally, they are propelled by the next product or a liquid such as water.
The type of propellant used depends on quite a few factors, but mostly the type of product, the objectives of pigging, and the facilities available.
Not all products or applications are able to use water as a propellant, but many can. ?
There are some key benefits of using water to push a pig when it’s possible.
Firstly, water, being a liquid that’s pumped, is highly controllable. It doesn’t compress in the same way air or other gases do. And pump speed is easy to control.
For example, using water meant we could slow the pig right down so I could clearly video it travelling at a very low speed on my phone (pigs usually travel much faster than shown in the video)
Plus, using water as a propellant helps rinse the line at the same time as pigging it. This saves a lot of time and makes batch changeovers much quicker.
If the pig were being propelled by air or other gas, the movement would be less smooth, and it would certainly be travelling a LOT faster.
Now, look at the separation between the white product, the pig and the water.
The water is completely clear. This means no white product is noticeably getting past the pig.
That’s because of the unique design of this type of pig – it is flexible, and creates a tight seal in the pipeline and maintains full body contact delivering exceptionally high product recovery rates, even around 1.5D bends.
When the pig has travelled through the length of the line to reach its destination (the “receiver” or “receive station”) it will be returned all the way back to the launch station housing using filtered compressed air.
Using compressed air to return the pig means it is quick, reliable, and convenient (most factories have a ready supply of compressed air).
All this happens automatically. The most an operator usually has to do is press a button on an HMI screen.?
How Do You Implement a Pigging System?
Of course, there’s much more to a pigging system than just pushing a pig through a pipe. There are multiple valves and other components, launch and receive stations, detectors, drop-offs, and not least programming and controls.
However, pigging systems are fast, reliable and incredibly effective.
They can be retro-fitted to existing liquid process systems, or incorporated in the design of new projects.
How Much Product Does a Pig Recover?
Returning to the fact that there’s virtually no product by-pass and that the water and sight glass after the pig is visibly clear. ?
HPS pigs typically recover 99.5% plus of liquids in full pipelines over the area which is ‘pigged’. ?
Which means, depending on the application, payback from a pigging system is usually just a few months (occasionally even days).
Ten-year ROIs from implementing HPS pigging technology often run into multiple millions of dollars/pounds/euros.
That’s why HPS pigging technology is in wide use in hygienic and process industries throughout the world. HPS provide the most advanced and innovative liquid product recovery (pigging) technology available.
These range from simple tank to filler designs, to highly sophisticated bespoke-designed multi-line, multiple-source to multiple-destination solutions.
More Information About Pigging
If you work for a company that processes liquids, and you want to increase yields, reduce waste, speed up changeovers and increase the efficiency and environmental sustainability of your liquid transfer operations, (and save your company tons of money) – just let me know in the comments or ping me a LinkedIn message and I’ll send over a free whitepaper, which tells you all about pigging.