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In October 2024, Nippon Sanso Holdings Corporation announced a strategic investment in Polaris, an Italian company founded in 1996 and specialising in the design and construction of plants for the separation, purification and production of gases (ranging from the chemical to the pharmaceutical industry), in which it now holds a majority stake. For Polaris, as its Chief Operating Officer Mario Masetto said at the time, the deal opened the door to larger-scale projects in air separation technologies, an area in which Nippon Sanso has extensive international experience.
The collaboration between the two companies has resulted in a technology offering that combines cryogenic condensation using liquid nitrogen with a patented distillation technology for the treatment of volatile organic compound emissions and the recovery of industrial solvents.
In industrial vent treatment, Polaris has long been a reference point in cryogenic condensation for reducing solvent emissions and recovering volatile organic compounds. Over time, the company has complemented this technology with its own proprietary distillation technology, designed to recover and separate complex solvent mixtures, including in cases where conventional distillation techniques are less effective.
The partnership with Nippon Sanso stems from the complementary nature of these areas of expertise: Polaris brings its established know-how in cryogenic condensation and solvent recovery, while Nippon Sanso contributes its international experience in the production, distribution and management of industrial gases. This collaboration has led to proposals aimed at transforming emissions treatment into an opportunity to recover and/or add value to industrial solvents. We discussed the subject with Matteo Compagnoni, Polaris’s sales manager for these applications, and Luca Moseneder, Industrial Marketing & Technologies Coordinator at Nippon Sanso at Nippon Sanso.
What problem are customers in the chemical and pharmaceutical industries asking you to solve, and how does combining cryogenic condensation and distillation go beyond simply reducing emissions?
Compagnoni - Emissions vary considerably from one industrial sector to another, and so do the technologies that can be applied. In the pharmaceutical industry, typical sources include reactor vents, vacuum-pump vents and highly concentrated process vents, often consisting predominantly of nitrogen. These are well suited to cryogenic condensation, more so than to activated carbon, combustion or biofiltration. Condensation makes it possible to separate volatile organic compounds from the gas stream, recovering them in liquid form, thereby facilitating their disposal or, where possible, their recovery. This is where distillation comes into play, as it allows us to go beyond simple abatement and recover a solvent that can, where possible, be returned to the production cycle.
How does the transition from condensation to distillation work, what treatment does the recovered solvent undergo before it can potentially be reused, and what levels of purity can you achieve even with complex mixtures?
Compagnoni - The basic principle is to cool the gas stream using a cryogenic fluid, thereby reducing the vapour pressure of the volatile organic compounds and causing them to condense. The lower the temperature reached, the higher the abatement efficiency. Liquid nitrogen makes it possible to reach very low temperatures, which is important for volatile solvents such as halogenated compounds (for example, dichloromethane), ketone compounds (for example, acetone) or alcohols, commonly used in the pharmaceutical industry. Another advantage is that, after transferring its cooling capacity and becoming gaseous, the liquid nitrogen can be recovered by the customer. This fits with the principles of the circular economy, while the low operating temperature makes the technology inherently safer, which is particularly relevant when handling flammable solvents. The recovered condensate can either be sent for disposal or thermal destruction in a more concentrated and controlled form, or subjected to distillation to recover the original solvents. This can be done in-house, but is often entrusted to a specialist third party. In the pharmaceutical industry in particular, the internal reuse of recovered solvent is always subject to purity assessments, and it is not uncommon for companies to prefer to outsource distillation and separation to a specialist provider.
Which industrial sectors are showing the most interesting growth in demand, and is there a recent case that particularly illustrates the value of the collaboration?
Moseneder - The pharmaceutical sector remains the area of greatest interest, and it is the focus of the development agreed upon in this partnership. One growing application is reactor cooling in active pharmaceutical ingredient production, which makes it possible to operate at controlled, very low temperatures, dissipate reaction heat rapidly and increase productivity. Polaris’s systems, including its condensation systems, are designed to meet the individual customer’s requirements, and the possibility to recover the nitrogen in full means that the plant has almost zero operating costs. This represents both an economic and an environmental saving, which continues to be highly valued in a high-value-added sector such as pharmaceuticals. A recent case involved a customer in north-west Italy, where we installed a cryogenic abatement system over the past few years that is now fully operational. It is an Italian customer with Japanese ownership, a coincidence we particularly appreciated because we brought Italian technology to a company that shares our own origins. We are also beginning to explore other sectors together, such as basic chemicals, coastal storage facilities and recycling, the latter of which has recently seen an update to the available reference techniques.
When you talk about recycling, which streams are you referring to in particular?
Moseneder – Waste from electrical and electronic equipment is among the areas that have attracted the most attention recently, along with other hazardous waste streams, including those containing PFAS. Polaris’s established standard in this field is the condensation of chlorofluorocarbons in refrigerator recycling, but there are other opportunities to explore in a sector where regulation is becoming increasingly stringent.
How much does the complexity of the starting mixtures affect plant design? Are there solvent families for which the combined technology delivers particularly strong performance, and others that naturally follow a more straightforward route?
Compagnoni - Condensation is a flexible technology, originally developed for applications such as pharmaceuticals, where flows are intermittent, both in terms of flow rate and solvent composition. The range extends from conventional solvents such as tetrahydrofuran, acetone and acetonitrile, through the alcohol group, to chlorinated solvents such as dichloromethane and fluorinated compounds, among the more difficult to treat using other technologies. Some compounds require specific attention. This is the case with compounds that may undergo polymerisation, such as acrylonitrile and vinyl chloride, for which the exchanger must be carefully configured to prevent blockages. Defrosting technologies are available to deal with the formation of solids, but when polymers are involved, the process requires particular care. The same applies to compounds that can solidify or crystallise at process temperatures, such as benzene or cyclohexane when present in relatively concentrated streams, and to highly volatile compounds with boiling points below zero, such as some light hydrocarbons and some fluorinated compounds, which require specific configurations of the cryogenic exchangers. As for distillation, the technology is fairly flexible, and the choice of distillation method depends primarily on the type of starting solvent and the required level of purity.
Beyond emissions treatment, what factors encourage a company to invest in this type of plant? Is the regulatory framework more important, or the economic return associated with recovering materials?
Moseneder – It is a combination of these two factors, together with the cost savings associated with reusing nitrogen, which is often the deciding factor. Compliance with emissions regulations is important and may vary over time or depending on how a pharmaceutical chemical plant develops, with expansions, new formulations and new solvents. There are therefore endogenous factors, linked to the customer’s production, and exogenous factors, linked to regulatory requirements that are often highly localised and can lead to differences between plants that are otherwise very similar. When this technology is compared with the alternatives available, the fact that the process itself does not generate additional emissions is also important. This is not something that can be taken for granted, given that the application was originally developed also for chlorinated solvents: burning them in a flare produces hydrogen chloride and therefore acid rain. At that point, with zero emissions and operating-cost savings from nitrogen reuse, the proposition becomes competitive.
Compagnoni – Cryogenic condensation must in some cases be combined with other technologies, for example with streams containing highly acidic or corrosive compounds, or with very specific thermodynamic behaviour, as in the case of carbon dioxide, which must also be managed appropriately within the condenser.
One final point: during our conversation, you referred to BATs in two sectors. What exactly are they, and how do they relate to your technology?
Compagnoni - BATs, or Best Available Techniques, as provided for under the European Industrial Emissions Directive, cite cryogenic condensation for the pharmaceutical sector. The reference is probably applicable to other sectors as well, although these documents are continually evolving. One point worth emphasising is that a single technology is often not sufficient. If emissions are highly acidic and contain a significant amount of solvent, it is advisable to combine a wet or dry abatement system specifically designed for acids with cryogenic condensation. Where very high abatement efficiencies are required, as they are in some European areas, cryogenic condensation can be used to handle most of the load, followed by a downstream absorption section to remove the final traces. Polaris also holds a specific patent for this solution, and the combination must always be carefully calibrated.
Moseneder - I would add that, in the latest negotiations we have been following, the integration of the signals required under incentives linked to the digital transition of industry has also emerged as a consideration. In some cases, this has enabled this type of plant to qualify for the tax credit available for technological upgrades at industrial facilities, an issue that has helped some customers decide to invest.
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