| Summary: | 碩士 === 國立臺灣大學 === 環境工程研究所 === 84 === The pyrolytic reaction of chlorinated plastics such as poly(
vinyl chloride )(PVC) will realease hydrogen chloride. Hydrogen
chloride released from the pyrolysis ,in turn, may affect the
mechanism of the pyrolytic reaction. In this study, the
pyrolysis of high density polyethylene (HDPE), being the
principal component of plastics in the municipal solid waste
(MSW) is carried out in the thermal gravimetric analysis (TGA)
system containing HCl gas. When the concentrations of hydrogen
chloride (CHCl) are between 0 and 500 ppmv, the curves of
residual mass fraction for pyrolysis of HDPE are about the
same. The influence of HCl is not obvious as CHCl<500 ppmv.
When the values of CHCl are between 500 and 1000 ppmv, the
curves of residual mass fraction of HDPE are influenced moving
to the higher temperature region. This indicates that HCl
inhibits the pyrolytic reaction of HDPE, resulting in the lower
conversion of HDPE. Furthermore, as concentrations of HCl are
between 1000 and 5000 ppmv, the curves of residual mass
fraction are not different. The composition of products for the
pyrolysis of HDPE in affected by the existence of HCl. On the
condition of no HCl, the yields of gaseous and solid products
are about 26.5 and 73.5 %, respectively. When the concentration
of HCl is 1000 ppmv, the yields of gaseous and solid products
are about 13.1 and 86.9%, respectively. Thus, hydrogen chloride
affects the pyrolysis rate and the composition of products for
the pyrolysis of HDPE. Its influence on the performance of
pyrolysis of plastics should be taken into account for the
design of pyrolytic system.
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