120
(Bhaskar et al. 2002). Pyrolysis is an efficient method of valorizing Electronic- waste
which can recuperate the valuable compounds with low emission of pollutants into
the atmosphere. Plastic wastes are converted into fuel by fast pyrolysis since it is a
promising technique for protecting the environment from these nondegradable plastics. During pyrolysis, plastics are thermally degraded and rehabilitated into oil,
gaseous, and charred products at (700–900 K) in an inert atmosphere. Pyrolysis
generates bio-oil with high bromine and chlorine content (Lopez et al. 2011).
Pyrolysis was carried out as single-step cracking process under the closed
environment. Fixed, fluidized bed and tubular reactors are used for pyrolysis process
and divided into three major processes based on process parameters like conventional, fast, and slow pyrolysis (Wu and Williams 2013). Fluidized bed reactor acts
as a better heat and mass transfer equipment yielding thin-layered plastic, suggesting the polymer degradation. Fast and slow pyrolysis methods follow the finest
route for converting brominated flame-retardant plastics onto clean fuels and valuable products than conventional pyrolysis process. Recently, a study revealed that
printed circuit boards pyrolysis resulted in a higher content of bromine, glass fibers,
and metals (Copper) (Shen et al. 2018).
6.3.4.1 Thermal Pyrolysis
Waste when subjected to thermal decomposition under zero oxygen environment
yields char, oil, and gaseous products which are further upgraded and used as fuels.
Several studies were reported on pyrolysis of brominated flame-retardant plastics in
various reactors (Hall and Williams 2006; Jung et al. 2012; Miskolczi et al. 2008).
Results suggest that pyrolysis of brominated high-impact polystyrene resulted in
higher yield of oil in fixed bed reactor. Pyrolysis oil contains toluene, ethylbenzene,
styrene, and cumene. Pyrolysis of brominated high-impact polystyrenes produced
98 wt% of oil containing 61.7 wt% of volatile products which were resulted due to
the thermal steadiness of polymeric chains. Pyrolysis of brominated high-impact
polystyrenes yielded oil around 500 mg/g plastic. In contrast, brominated
acrylonitrile- butadiene-styrene pyrolysis yields 400 mg/g of plastic.
6.3.4.2 Co-pyrolysis
Combined pyrolysis technique basically deals with two or more dissimilar materials
as resource to yield oil with improved quality and quantity. Co-pyrolysis can reduce
manufacturing cost and resolve several problems in managing waste. Due to inherent complexity, several issues arise in Electronic-waste management. Co-pyrolysis
improves quality and quantity of pyrolysis oil without any catalyst or solvents,
which made this method an unavoidable technique in industrial applications (Abnisa
and Daud 2014).
J. Arun and K. P. Gopinath
(Bhaskar et al. 2002). Pyrolysis is an efficient method of valorizing Electronic- waste
which can recuperate the valuable compounds with low emission of pollutants into
the atmosphere. Plastic wastes are converted into fuel by fast pyrolysis since it is a
promising technique for protecting the environment from these nondegradable plastics. During pyrolysis, plastics are thermally degraded and rehabilitated into oil,
gaseous, and charred products at (700–900 K) in an inert atmosphere. Pyrolysis
generates bio-oil with high bromine and chlorine content (Lopez et al. 2011).
Pyrolysis was carried out as single-step cracking process under the closed
environment. Fixed, fluidized bed and tubular reactors are used for pyrolysis process
and divided into three major processes based on process parameters like conventional, fast, and slow pyrolysis (Wu and Williams 2013). Fluidized bed reactor acts
as a better heat and mass transfer equipment yielding thin-layered plastic, suggesting the polymer degradation. Fast and slow pyrolysis methods follow the finest
route for converting brominated flame-retardant plastics onto clean fuels and valuable products than conventional pyrolysis process. Recently, a study revealed that
printed circuit boards pyrolysis resulted in a higher content of bromine, glass fibers,
and metals (Copper) (Shen et al. 2018).
6.3.4.1 Thermal Pyrolysis
Waste when subjected to thermal decomposition under zero oxygen environment
yields char, oil, and gaseous products which are further upgraded and used as fuels.
Several studies were reported on pyrolysis of brominated flame-retardant plastics in
various reactors (Hall and Williams 2006; Jung et al. 2012; Miskolczi et al. 2008).
Results suggest that pyrolysis of brominated high-impact polystyrene resulted in
higher yield of oil in fixed bed reactor. Pyrolysis oil contains toluene, ethylbenzene,
styrene, and cumene. Pyrolysis of brominated high-impact polystyrenes produced
98 wt% of oil containing 61.7 wt% of volatile products which were resulted due to
the thermal steadiness of polymeric chains. Pyrolysis of brominated high-impact
polystyrenes yielded oil around 500 mg/g plastic. In contrast, brominated
acrylonitrile- butadiene-styrene pyrolysis yields 400 mg/g of plastic.
6.3.4.2 Co-pyrolysis
Combined pyrolysis technique basically deals with two or more dissimilar materials
as resource to yield oil with improved quality and quantity. Co-pyrolysis can reduce
manufacturing cost and resolve several problems in managing waste. Due to inherent complexity, several issues arise in Electronic-waste management. Co-pyrolysis
improves quality and quantity of pyrolysis oil without any catalyst or solvents,
which made this method an unavoidable technique in industrial applications (Abnisa
and Daud 2014).
J. Arun and K. P. Gopinath