New technology from thermal processing engineering firm Despatch offers the end-user a viable and readily available product that could meaningfully lower the cost of producing carbon fibre.
Despatch announced last month that its next-generation Split-Zone oxidation oven with the company’s proprietary Novariance Technology will enable manufacturers to aggressively push the oxidation rate during the manufacture of carbon fibre to reduce the oxidation cycle time, thereby lowering the cost of oxidised fibre.
By creating two discrete thermal profiles for the upper and lower half of the chamber, the temperature in the upper half of the oven can be increased by several degrees, advancing the rate of oxidation of the fibre within the same process chamber.
Novariance Technology, with its patent-pending orifice-plate nozzle structures, eliminates the side-to-side and directional variance inherent in conventional nozzle designs.
In today’s conventional carbonisation lines, the oxidation process presumably consumes the most energy, has the largest carbon footprint and requires the largest capital investment.
With this in mind, production processes alternative to conventional oxidation, such as plasma, as well as alternative precursors to the traditional polyacrylo- nitrile-based precursor, are seen as the best path to achieving lower-cost carbon fibre. Generally, these methods have received the most attention in recent years.
Further, Despatch highlights low process variability, effective and controllable heat transfer rates and increased zones of control as key to reducing the oxidation process cycle time from a typical 60-minute to a 90-minute cycle.
Previously, trade-offs in ease of maintenance or capital equipment costs have made integration of these factors cost prohibitive, limiting potential cycle time reduction, notes the company.
However, Despatch carbon fibre division GM Steve Oman highlights that the Split-Zone oxidation oven will lower process variability, widen the window to optimise heat transfer rates to a specific precursor and double the effective number of zones of control.
“We estimated that a 25% cycle time reduction, or more, can be achieved with Split-Zone oxidation technology,” he says.
Despatch will be showcasing its Split-Zone oxidation oven at its Lakeville facility, in Minnesota, US, during the fourth quarter of 2015.