Thermal-catalytic degradation kinetics of polypropylene over BEA, ZSM-5 and MOR zeolites

Non-isothermal degradation kinetics of filled with rise husk ash polypropene composites

“…Nowadays, incineration is the more widely used way to eliminate solid residues and it is also used for generation of electric and calorific energy at the same time. Uncontrolled incineration, however, can produce serious air pollution, environmental and health problems due to the possible emission of toxic flue gases (dioxins, furans), acid gases and heavy metals [5,6,18]. For this reason, the search for different recycling alternatives (thermal or oxidative degradation) is more and more necessary [19,20].…”

“…A recently reported alternative is to transform the polymer waste into hydrocarbons in order to produce low molecular mass chemicals, clean hydrocarbon, chemical resources, fuels, gasoline, or other valuable products such as lubricants by thermal or catalytic degradation. The thermal degradation (pyrolysis) of the polymer macromolecules in the absence of oxygen or under vacuum at elevated temperatures gives a mixture of hydrocarbons [5,6,8,12,18,21]. According to the data from the gas chromatography/mass spectrometry analyses (GC/ MS), the thermal degradation of polypropene in nitrogen medium gives dienes, alkanes, and alkenes up to C 31 hydrocarbons [17].…”

Polyolefins and the environment

“…Similarly, survey of interaction among the other factors indicated that there is not a significant interaction [151]. The effects of catalysts on the catalytic degradation of polymer have also been investigated by contacting melted polymers with catalyst in fixed bed reactors [152,153], heating mixtures of polymer, and catalyst powders in reaction vessels [154,155], and passing the products of polymer pyrolysis through fixed bed reactors containing cracking catalysts [156].…”

Tertiary recycling of polyethylene waste by fluidised-bed reactions in the presence of various cracking catalysts

“…Studies of the effects of catalysts on the catalytic degradation of polymer has been performed by contacting melted polymer with catalyst in fixed-bed reactors [10][11][12], heating mixtures of polymer and catalyst powders in reaction vessels [13][14][15], and passing the products of polymer pyrolysis through fixed-bed reactors containing cracking catalysts [16][17][18]. The use of fixed beds or adiabatic batch where polymer and catalyst are contacted directly leads to problems of blockage and difficulty in obtaining intimate contact over the whole reactor.…”

“…In addition, the shape selectivity exhibited by certain catalysts allows the formation of a narrower distribution of products, which may be directed towards fuels, chemicals and valuable hydrocarbons with higher market values. Lots of studies have been conducted describing the cracking of pure polymers over various cracking catalysts with the textural properties, such as surface area, particle size and pore size distribution, and the differences in the catalytic activities as they control the accessibility of bulky plastic molecules to internal catalytically active sites [10][11][12][13][14][15][16][17][18][19][20]. In this way polymer wastes are converted into monomers, chemicals or various hydrocarbons.…”