Preparation of ZSM5 from Several Types of Coal Fly Ash using Hydrothermal Method for Catalytic Pyrolysis using Heat Pipe as a Passive Cooling for High-Density Polyethylene Waste

Abstract

Plastic waste processing technology is advancing to minimize the growing plastic waste
today. HDPE (high-density polyethylene), one type of plastic that is widely used in our
daily lives, representing plastic waste that takes a long time to unravel naturally. This
study discusses the preparation of the ZSM5 catalyst as the main component, which is
made from several types of Indonesian coal fly ash. It will be used to convert HDPE waste
into diesel fuel using low energy pyrolysis technology with liquid collection system. The
pyrolysis process used is a thermal pyrolysis with a passive cooling system, consisting of
several straight heat pipes, which are run for the raw material 50g on the temperature
process done at 500 and 550 °C in 3 hours. Therefore, ZSM5 as a catalyst is necessary to
aid the process of converting plastic waste to diesel fuel, which is expected to have the
same characteristics as diesel by developing thermal pyrolysis for catalytic pyrolysis.
ZSM5 as catalysts are also made from the power plants’ fly ash of the four different types
of coal, namely Amurang, Bukit Asam, Adaro and Kidenco. Furthermore, the best type of
fly ash is selected to create ZSM5. The minimum Si/Al ratio is 5, ideally in the range of 5-
50. The ratio value of the fly ashes of Amurang, Bukit Asam, Adaro, and Kidenco are
21.95,10.02, 2.40, and 3.79, respectively. Thus, Amurang and Bukit Asam fly ashes were
selected to be formed into ZSM5. In the next step, Amurang and Bukit Asam fly ashes are
processed by hydrothermal methods to remove impurities by using 10 M HCl which is
heated at 550oC for 1 hour to obtain Supernatan solution, then added sodium dodecyl
sulfate (SDS) 0.21 M and NH4OH until reaches PH of 9.5-10. The fly ash is then heated
in the oven at a temperature of 97 oC for 5 days, and then heated again for 5 days in an
oven with a temperature of 550 oC. BET (Brunaeur-Emmet-teller) test as a test
characteristic catalyst is performed on the results ZSM5. The results of ZSM5 BET test
showing the surface area of Amurang fly ash (9.11 m2/g); Bukit Asam fly ash (21.25
m2/g), volume of pore Amurang fly ash (0.02 ml/g); Bukit Asam fly ash (0.03 ml/g), and
the pore size Amurang fly ash (40.12 Å); Bukit Asam fly ash (25.93 Å). From these results
it can be stated that the pore size matches the characteristics of ZSM5.