Pigging systems: what they are and how they work

The optimisation of resources and operational efficiency have become fundamental pillars for maintaining a high level of competitiveness in the process industry. Within this context, pigging systems offer strategic technology for the advanced management of industrial fluids. The need to handle high-value, high-density or high-viscosity liquids requires solutions that are capable of minimising the waste of raw materials, simultaneously ensuring highly flexible production. Whether operating in the food, chemical or pharmaceutical sectors, taking a methodical approach to the maintenance and management of transfer pipelines enables companies to respond promptly to modern production challenges.

What is a pigging system or pig system?

It is a product recovery system in which a solid, flexible device (known as a “pig”) is introduced into a fluid pipeline. The maximum diameter of the pig is designed to be slightly bigger than the inner diameter of the pipeline to be treated, applying constant and even pressure against the inner walls of the line. Its main purpose in industrial processes is to move along the pipeline, driven by a propellant fluid (such as compressed air, nitrogen, water or another type of fluid), acting as a piston that pushes the residual liquid forward at the end of a transfer.

This approach clears the pipeline of deposits and allows the recovery of up to 99% of the residual product in the pipes. In a traditional plant, this product would be lost during the cleaning cycles. The precision of the pigging system transforms what was previously considered waste to be disposed of into finished product ready for sale, directly improving operating margins.

Would you like to find out more about how the pigging system prevents product wastage in food processing plants? We talk about it here.

Are you looking for technical support to optimize resources?

Request a preliminary consultation with a Granzotto Impianti expert.

How a pigging system works

The technical operating principle requires careful engineering and high-precision components, progressing step by step along the transfer line.

The pig starts out in a resting position inside a launch station (known as a “pig launcher”). After the main transfer of the fluid has been completed and the line has been partially emptied, the station is isolated and the propellant fluid is introduced. The pressure exerted pushes the pig along the pipeline. The device empties the pipes as it travels, mechanically pushing the residual product and transporting it to its final destination, which may be a storage tank or a filling machine. At the end of its journey, the pig reaches a receiving station (known as a “pig receiver”), where it is safely intercepted and retained. Depending on the automated configurations of the pigging system, the device can then be reintroduced into the line to travel in the opposite direction or removed for routine inspection and maintenance.

The whole cycle is supervised by automated monitoring systems that track the pig’s position in real time.
G-RECO pig system.

In this context, the engineering solutions developed by Granzotto, such as the G-RECO pig system, incorporate these phases to ensure maximum safety and customisation in terms of materials and dimensions, in accordance with the plant’s specifications.

Applications and sectors of use

The versatility of the pigging system makes it ideal for a wide range of industrial applications, particularly in sectors that handle high-density, high-viscosity fluids and products with a high commercial value.
The design philosophy remains consistent, adapting to the specific characteristics of each sector:

Food industry
The pigging system is used to empty and clean pipes used to transport fruit juices, sauces, jams, creams and dairy products, significantly reducing the risk of cross-contamination between different recipes.
Wine industry
In modern wineries, the pigging system ensures the transfer of wine and related products, minimising losses, protecting the liquid from oxidation and guaranteeing its original quality.
Chemical and petrochemical industry (Oil & Gas)
Historically used for cleaning long-distance pipelines (as in the case of the pigging system for oil pipelines) and for the transfer of mineral oils, lubricants, paints, solvents and detergents, where residues could compromise the integrity of subsequent batches.
Pharmaceutical and cosmetics industries
Health and hygiene requirements are extremely strict in these contexts, as is regulatory compliance; the pigging system allows lines carrying creams, gels or syrups to be completely emptied before sanitisation cycles begin, preserving the absolute purity and traceability of the raw materials.

How can the problem of industrial residue contamination in lubricating oil production be solved? We talk about it here.

What are the advantages of a pigging system?

The implementation of a pigging system for the recovery of residues and the subsequent cleaning of the pipes offers a range of benefits: it increases productivity and the quality of the final product, improves the versatility of the plants and reduces the environmental impact.

Product recovery
Recovery of over 99% of the product along the line, turning waste into profit and reducing the risk of blockages.
Reduction of CIP time and costs
Less residue means lower consumption of chemical detergents, water and sanitising solutions, as well as much shorter wash cycles, resulting in more time available for active production.
Reduction of disposal costs
The reduction of the volume of polluting effluent requiring treatment significantly reduces the costs associated with industrial waste management and the impact on the environment.
Quality and versatility
The pigging system excels at handling viscous and high-density liquids, facilitating rapid production changes and minimising the risk of cross-contamination.
Measurable environmental sustainability
Alongside the economic benefits, a key factor in using the pigging system to empty pipes is measurable environmental sustainability. The synergistic use of pigging systems and CIP cleaning modules results in a significant reduction in the ecological footprint, which is particularly important in geographical or production contexts characterised by water stress.

What strategies can be employed to reduce environmental impact and promote sustainability in the cosmetics industry? We talk about it here.

For Granzotto, sustainability translates into tangible solutions: the combination of G-RECO recovery systems with G-CLEAN cleaning-in-place modules (which reuse the final rinse as the first wash in the next cycle) enables businesses to optimise their energy and environmental KPIs, as also highlighted in their sustainability reports. In short, the combination of these technologies is the ideal solution for a profitable, long-term ecological transition.

Recovering most of the residual product from the line is a goal that can be achieved in numerous production contexts. Please contact us so that together we can assess whether and how a pigging system can be incorporated into your process.