Yields of the primary pyrolysis products are temperature dependent. At 500 degrees Celsius, a maximum oil yield of 79 percent weight can be obtained. As you can see from the graph below, char yield decreases and the gas yield increases with temperature.
[Courtesy of: Biomass Technology Group.]
Pyrolysis converted 40% of the composite plastic waste into oil, which has fuel properties similar to those of apetroleum-derived gas oil. In addition, 25 percent weight of the oil is styrene, which is used in the production of the styrene-polyester copolymer. 95 percent weight of Wax produced from pyrolysis is phthalic anhydride, which is used in the production of the composite material. The use of the oil and wax as a chemical feedstock in the production of new plastic materials has much greater value than the their use as substitute.
Low Temperature Benefits of the Pyrolysis Process…
Glass fibre is one of the major and valuable constituents of composite plastic wastes because fibres become very brittle and quickly lose strength when temperature above 800 degrees Celsius, the successful recovery of glass fibre without degrading the fibre strength need a process that operates at a temperature that is lower than 800 degrees Celsius. In the case, Pyrolysis is a perfect fit because it has the low process temperature of less than 500 degrees Celsius, thus retaining the strength and flexibility of the virgin glass fibre.
Separation and Re-Using the Glass Fibres…
Separation of the glass fibre from the filler can be achieved using a drum carder machine. In this process, fibres are gently separated from the friable char and filler matrix. The separated fibres can then be used as char-coated fibres to produce new composite plastic materials. On the other hand, a blackened glass fibre can also be cleaned using low-temperature furnace oxidation to burn off the char to produce cleaned fibre.
The recovered glass fibre, both cleaned and char-coated, are made into test samples of a new composite. When a test sample incorporating 25 percent weight of the recovered glass fibre and 75 percent weight of virgin glass fibre is compared to a controlled sample containing 100 percent weight virgin glass fibre, the results shows that up to 25 percent weight of recycled fibre could successfully be incorporated into a new composite while still meeting manufacturers specifications. This means the recycling process is successful!
Section I: Introduction
Section II: Present (YOU ARE CURRENTLY IN THIS SECTION)
Section III: Future
Complete Table of Contents
Reference