Travelling throughout the country I often come across fiberglass shells of once much loved boats sitting in fields, boatparks in harbours and sometimes on shorelines.
Steel vessels tend to be easier to offload and have residual value, especially if lead ballast is included or if the hull is aluminium. Timber vessels are often left to rot and decompose the skeletal remains of ribs and frames are found on the banks of many rivers and harbours around the country. FIBERGLASS is a different story…. with a very slow decay rate, and often controlled materials in the layup, a efficient use for old fiberglass structures is required. We should take a look at how this is undertaken elsewhere!
“Three processing methods are used for recycling fiberglass: grinding, incineration, and pyrolysis. Grinding is the most cost effective option —reducing material to small pieces or powders to be reused in other products. Potentially all material that can be reground can be used as recyclate; there is little or no unused waste. Powdered FRP in some countries ends up in asphalt for road and motorway surfaces
Incineration is the least effective as energy retrieval from incineration is low and unusable contaminated ash (Calsium Oxide) in large amounts generally ends up in landfill.
Pyrolysis is the process of chemically decomposing or transforming a material into one or more recoverable substances by heating it to very high temperatures in an oxygen-depleted environment. This is different from incineration, which takes place in an open atmosphere….Pyrolyzed fiberglass decomposes into three recoverable substances: pyro-gas, pyro-oil, and solid byproduct— all of which can be recycled. Scrap automobile tires are disposed of by pyrolysis (the tire mountain in the United States is over 3 billion tires, growing at the rate of 250 million tires a year).
To pyrolyze SMC (sheet moulding composite), it is shredded into 2” squares that are fed directly into the pyrolysis reactor by a vacuum assist, which also draws off most of the oxygen in the atmosphere. The reactor is then heated to around 14000F (7760C). At about 5000F (2760C), the hydrocarbons in the resin decompose into gas. The gas is drawn off and sent through a scrubber, which separates it into pyro-gas and pyro-oil. The pyrogas is very clean and has an energy content similar to natural gas. It can be sold as a natural gas replacement, and it fuels the burners of the pyrolysis reactor so that the reaction is self-sustaining. Pyro-oil is similar to heavy crude oil and, as such, it has less value than normal crude oil, but it can be blended with other fuel oils or incorporated into asphalt. Pyro-gas and pyro-oil comprise about 25% of the pyrolysis traction output in roughly equal amounts. These are free of sulphur, halogens, phosphorous, heavy metals, or other elements that can cause environmental problems.”
One example from Germany, company Zajon describes the process as follows:“The production of cement is dependent on large quantities of sand. And sand is also the main constituent of glass, and thus also of fibreglass. Fibreglass additionally contains polyester which can be used as an energy source in cement production, thereby replacing the use of fossil fuels.”“Fiberline sends the fibreglass waste to Zajons in Germany.Zajons consolidates the fibreglass in a giant crusher and adjusts the calorific value by adding other types of recycling materials.The waste is sent to the cement manufacturer.Holcim feeds the waste to the huge kilns that produce the finished cement.Recycling 1000 tonnes of Fiberline profiles in cement manufacture saves up to 450 tonnes of coal, 200 tonnes of chalk, 200 tonnes of sand and 150 tonnes of aluminium oxide (Source: Holcim, 2010). And the recycling process produces no dust, ash or other residues.”