Report: Challenges in wind turbine blade recycling
S. Himmelstein | June 01, 2020The energy generated by wind turbines may be viewed as clean and green but decommissioned turbine blades are not. With blades spanning up to 260 ft and weighing an average of 36 tons, old or broken blades pose a disposal dilemma problem, with landfilling the most commonly selected option. Prospects for recycling these renewable energy components were recently explored by the Electric Power Research Institute and the American Composites Manufacturers Association.
Up to 50,000 tons of blades per year are projected to enter the end-of-life stream in the U.S. by 2023. The bulk of the blades is composed of fiber-reinforced composite, which presents size reduction challenges (either glass or carbon fiber). The use of pyrolysis, burning in a cement kiln and grinding blades so particles can be used as filler were examined as feasible end-of-life routes.
Mechanically size-reducing the composite and using the resulting material as a filler or combining the low-
Decommissioned wind turbine blades are typically cut up and transported by truck for solid waste disposal. Source: Derek Berry/National Renewable Energy Laboratoryvalue end-product with other materials for use in decking, insulation and building panels, is hampered by market and economic challenges. Grinding can create a fine dust irritant, and shards pose handling problems. A large decline in the mechanical properties of the recycled material is also noted.
Recycling using the cement kiln eliminates the need for landfill, recovering both energy and raw materials needed to produce cement. The inorganic glass fiber is reprocessed into cement and the resin provides an energy offset. Barriers to widely deploying this recycling option include a loss of material characteristics and the need for a high volume of composites to make the additional processing economical, as the composite portion of the feedstock must be combined with other materials to provide the required consistency and BTU.
The pyrolysis process generates clean fuel gas to heat the primary reactor and yields char with recoverable carbon fiber and glass fiber reinforcement for re-use in other polymer systems. This option offers more attractive economics for recovery of carbon fiber than for glass fiber, but it requires more technology development and a higher initial investment than the other options.
Recommendations for improving the economics and logistics of options for wind turbine blade management include continued development of a commercial-scale facility for front-end processing of composites scrap for use in recycling, cement kiln feedstock and/or pyrolysis demonstration.
Well, couldn’t you put the blades in a large room with air and water filtration and capture? Then you could use a water jet system to chop up smaller or a robotic arm water jet system to cut into tiny pieces.
The large scale GRP/FRP roof of Manchester City football club was built in 1982. It was removed in 2003 and has since been used as pig shelters in the local area.
Re-purposing of elements of the wind blades, has to be considered as a viable solution. Non structural building materials would be a key area to consider.
The photo of the pig shelters looks a bit feeble but the pigs get under there OK and their reuse utilised a huge GRP project of its time, still in use 38 years later! Strength no longer matters here.
If recycling or re-purposing the blades is not an economic or sustainable option then the design is wrong. However, wind turbine is not an economic proposition anyway so surprise surprise that the energy companies cannot afford to dispose of the blades!
There is a possibility that with minimal processing, and the addition of rocks or broken concrete to their interiors, used / discarded wind turbine blades might be useful foundations for artificial reefs, e.g. when overlaid in a loose matrix or stacked arrangement. While past efforts to use discarded fiberglass boats have met with mixed results when abandoned in shallow waters without adequate preparation, there appear to be other reefs involving fiberglass hulls after proper preparation and ballasting and deployment in relatively deep water which have been successful and lasted for decades.
See pages 131-134 of:
https://www.gsmfc.or
Recycling methods to create reusable components as opposed to creating inorganic contaminant is preferred. There will always be mechanical size-reducing. Tree shredders are portable and affordable, a custom size with filtration systems should be feasible. A simplified kiln tumbler to process components separation by melting point and centrical weight channeling does seam to be the next crude step.
The pyrolysis process does sound to me to be a complicated process to reuse byproducts of the binder resins. I would not imagine enough plastic would be present for a quality yield of clean fuel gas.
Other option not mentioned are:
1. Verneuil method also called flame fusion. I would not expect to manufacture synthetic gemstones, but who knows what might be sought out after.
2.Yull Brown first patented an electrolyzes in 1977 to utilize the power and benefits of Brown's gas also called Oxyhydrogen to date. Using electrolysis to disassociate the molecules of water into oxygen and hydrogen to create stoichiometric combined mixture with autoignition at 570° Celsius and flame can reach a temperature of 2800° Celsius. The common melting point of glass is between 1400-1600 degrees Celsius. Carbon doesn’t really have a melting point. Well, theoretically it does but it doesn’t melt. It sublimes at around 3550° Celsius. Just imagine finding a way to use a byproduct of wind turbine blade recycling to isolate componts for ion batteries or such.
A note: Tungsten's melting point of 3422 °C is the highest of all metals and second only to carbon (3550 °C) among the elements. I have seen a Utube video of Oxyhydrogen torch flame burn through tungsten welding rod like a knive to butter. Was it faked or does the molecular reaction excite the tungsten to a higher heat? My guess it may have been an oxidation decentration instead of melting? Or being the mixture reaction which turned back into water may have jetted the material away?
A simple experiment: Burning a blade straight away to sample an Oxyhydrogen torch reaction would not cost much. At least, it could be a way to cut them to smaller pieces.