Helium recovery cuts fibre cost
With demand for fibre sluggish, manufacturers are seeking ways to reduce spending and control critical assets. They must develop a hedge against future increases in the fibre manufacturing cost as they await a recovery that could take years.
Helium recovery and recycling provides a new tool for reducing operating costs - important during a period of rising prices and uncertain supply. Cable making accounts for about 15% of helium use, and demand is growing. Yet, there are only 12 helium sources in the world, with some nearing exhaustion.
According to the fibre-optic solutions group of UK supplier BOC, the supply of helium - extracted as a by-product from natural gas - is nearly sold out, with significant new sources not expected until at least 2004. The result is a steep increase in prices and operating costs for fibre makers - spawning new technologies for the recovery and reuse of helium.
During drawing, the fibre strand is rapidly cooled in a flow of helium before being coated with a resin for extra strength. "Helium is injected into the annular space between the fibre and the cooling tube at a flow rate necessary to achieve the required fibre temperature," says Art Shirley, director of commercialisation and technology for BOC's fibre-optic solutions group. "As the fibre draw speed is increased, proportionally more helium is introduced into the cooling tube to achieve the required temperature."
Several companies, including BOC, Air Products & Chemicals, and Praxair, offer helium recovery systems, boasting a recovery rate of 70-90% at purities of over 99%.
While mostly used for cooling during drawing, helium may also be used as a carrier gas in preform deposition and a sweep gas in preform consolidation. Each introduces different impurities, contaminant levels or heat levels into the helium.
Fibre makers can no longer afford to use "once through" helium flows. Turnkey systems are being evaluated, including compact systems that with software for controlling and monitoring recovery.
"Helium recovery and recycling from industrial processes just makes economic and strategic sense," says Shirley. "It provides fiber manufacturers with on-site control over their source of helium supply and helps them reduce operating costs."