Liquid products with waste plastics

K. H. Lee, N. S. Noh, D. H. Shin, Y. Seo, Comparison of plastic types for catalytic degradation of waste plastics into liquid product with spent FCC catalyst, Polym. Deg Stab., 78, 539-544 (2002). 

In the series described thus far, it was found that the degradation of waste plastics proceeds efficiently by both thermal pyrolysis and hydrolysis in a steam atmosphere. A wax and carbonaceous residue produced by the hydrolysis of PET are decomposed by reaction with steam over an FeOOH catalyst, the activity of which remains stable in a steam atmosphere. However, the liquid product from generated from the process mentioned above contains a large amount of heavy oil, as shown in Figure 6.10. Both catalysts and chemical processes are required for efficiently upgrading the quality of the heavy oil. 

The liquid product obtained from thermal cracking can be either catalytically cracked/ hydrocracked or co-processed with a refinery feed. Since the catalytic cracking of oil derived from MWP is more or less problematic, any cracking catalyst can be applied to oil derived from pyrolysis of plastics. But the yield and the quality of gasohne obtained from cracking step vary with the type of catalyst and the properties of the pyrolytic oil derivated from waste plastics. 

Lubricating oil. A new process has been developed for the conversion of waste plastic and Fischer-Tropsch (FT) wax to lube range molecules that can be hydroisomerized to low pour point lube base oils of unconventional base oil (UCBO) quality. The process employs pyrolysis, a thermal, noncatalytic, low-pressure reaction where high-molecular-weight molecules are cracked to ones of lower molecular weight. The major by-product is diesel, with little production of C4- gas. The by-product liquids are highly olefinic and could be oligomerized to provide additional base oil. 

The product distribution for the catalytic coprocessing of waste plastics with petroleum was also reported by our group [14]. High yields of liquid fuels in the boiling range... 

The thermal degradation of PE mixed with polyethylene terephthalate (PET) and PE only degradation were compared. The presence of small amounts of PET is quite possible with the mixture of PE, PP, and PS, which is generally considered as municipal waste plastics. The yields of product gases, liquids and residues from the degradation of PET and the mixtures of PET and PE in ratios of 1 9 and 2 8 are shown in Table 18.4. Unlike PE or PVC, no liquid products could be obtained from the degradation of PET. The decomposition of PET proceeds with the production of a large amount of pale yellow... 

The pyrolysis process for waste recycling is frequently done at larger scale than analytical pyrolysis. However, analytical pyrolysis studies are performed independently for the understanding and the optimization of such processes [10,16-19]. Also, model mixtures can be used in parallel with real samples. For example, the comparison of thermal degradation products from real municipal waste plastic and model mixed plastics can help understand the compounds generated in waste incinerators. In one such study [20], analytical pyrolysis of real municipal plastic waste obtained from Sapporo, Japan and model mixed plastics was carried out at 430 °C in atmospheric pressure by batch operation. The chlorinated hydrocarbons found in degradation liquid products of poly(ethylene)/poly(propylene)/ poly(styrene)/poly(vinyl chloride) and other polymeric mixtures were monitored. It was determined that the presence of poly(ethylene terephthalate), in addition to chlorinated plastics in the waste, facilitates... 

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