Gas recycling, Neighborhood 91

Originally published in Gasworld on February 3, 2020.

By Joe Arencibia, President and CEO, Arencibia

The growth of additive manufacturing (AM) at the end of the last decade has brought new opportunities and applications for gas supply and recycle, specifically argon and helium. It’s also brought a fresh and holistic view of the entire value chain, which uses these inert gases directly in the process or for controlled atmospheres: from high-grade alloy production to printing and through final part processing.

Manufacturers with medium and large gas usage – those that use more than
25 million standard cubic foot (SCF) of argon or 2 million SCF of helium per year – achieve substantial savings and risk reduction with integrated,
centralized gas recovery systems that recycle over 90% of their inert gas rate.

But smaller gas users, particularly AM print operations, can suffer at the wrong end of the economies of scale. Without enough gas throughput to justify recovery, they’re left with absorbing the high cost and inconsistent availability of argon and helium on a once-through basis. This puts them at a competitive disadvantage on multiple fronts: production margin, resource reliability, and future pricing uncertainty.

In the industrial AM space, a newcluster development has launched which solves this scale disadvantage for smaller gas users and provides greater value to larger users, as well. The recently announced Neighborhood 91 campus at Pittsburgh International Airport will employ sitewide noble gas recycle as a utility service from Arencibia,the market leader in large-scale gas recovery. By locating more steps of the AM production network within a single ecosystem, the script is flipped on gas supply scale issues, with tenants gaining an intrinsic and integral advantage
against global competition.

While the concept of gas recovery as a multi-customer utility may seem novel, it’s a natural extension of what’s done at a number of Arencibia’s current recovery operations. Large, integrated customers in aerospace metals can have multiple argon users exhausting to a central gas recovery unit: sources like atomizers,presses, and heat treatment. The same
customers may also have multi-point helium usage in plasma and cooling
operations. In electronic materials, manufactures have dozens of tools with
continuous demand for argon or helium, which are centrally recycled, as well.

The strategy at the Neighborhood 91 campus employs those same
technologies, with a twist. Now a larger portion of the supply chain is co-located in a way that allows the central recovery operation to serve all scales of gas users,with inexpensive gas costs for all tenants. This creates a true, plug-and-play market for low-cost inert gases, with substantially reduced supply risk, and a low carbon footprint to boot.

There are, of course, some new challenges to contend with too. Standard
sets of delivery pressures had to be established, which adds some minor
inefficiencies in operating and capital. The diversity of customers and types
of unit operations also adds some complexity to managing high and low operating cycles, impurities, and onboarding new operations as the site
grows. But the technology is adaptable to these challenges, both on the hardware and software side.

Arencibia’s gas recovery platforms, with a total operating history of well
over a century, fall into several main technology categories, depending on
the application. High-pressure (>600 psig) and high flow (>500 scfm) argon
systems are processed cryogenically using liquid nitrogen as a working fluid and high-pressure liquid pumps as the main system driver. The high
upper pressure limit of these pumps allows systems to achieve process flows and delivery pressures that can exceed 5000 psig. This configuration has the advantage of highly scalable flow and pressure limits, but with a higher use of liquid nitrogen for condensation and purification, which adds to the operating cost. Typical applications would be powder production via atomization and hot isostatic pressing (HIP).

For lower pressure argon systems,the operating cost of recycle can be further improved using compressors, as well as some liquid nitrogen, as the
primary driver. This allows for a more efficient thermodynamic balance on
the recycle system, but is limited by the feasible combination of compressor
flows and outlet pressures. Applications include 3D printing, silicon wafer production, and heat treatment. Helium recovery systems are almost exclusively handled in the gas phase. There’s a great variability in the usage cycles from different customer processes, but the basic process is in three main steps: low pressure collection and treatment, high pressure compression, and final purification. Systems usually end with high pressure tube storage to mimic a customer’s on-site delivered gas supply. Helium recovery applications include quenching, small-scale atomizing,
plasma processes, semiconductor production, and 3D printing.

Completing the physical recovery operations is a state-of-the-art software
backbone, which together are known as MARS. This employs monitoring, big data analytics, and machine-learning algorithms across multiple operations to maximize gas recovery efficiency at customer sites, like the tenants of the Neighborhood 91 campus.

Overall, new approaches to grouping utility-style gas recovery – both at multicustomer clusters and multi-point single customer sites – are being driven by a combination of creative commercial approaches, technological growth, and changing market dynamics. New ways of manufacturing, such as AM, drive new thinking on the entire production chain.

Rising gas costs and reduced availability have created incentives to expand and adapt recovery platforms with hardware, software, and data advancements that address those needs. The end result is a new scale of recovery service that can benefit a wider range of gas users.