Theory of Plastics Pyrolysis

All the plastics have their own activation energy when cracked. The corresponding reaction temperamres required are different. At appropriate temperature, pressure and with 

The components of products from thermal and catalytic cracking of HDPE, LDPE, LP, PP, PS were analyzed [48], and the results are shown in Table 28.2 and Table 28.3. The products from thermal cracking of HDPE, LDPE and LP (linear polyethylene) are mainly wax-like substances at normal temperamre. The fraction under 200°C recovered from HDPE accounts for 16% of the total cracking products, while that from LP accounts for 23%. Compared with tlie products of PE, PP produces less solid residue, but more liquid components, and PS produces the highest proportion of liquid fraction, which is 99.17% by thermal cracking and 99.56% by catalytic cracking. 

In another experiment conducted by Sakata [49], the degradation of PE produced liquid products which consisted of C5-C25 hydrocarbons with a yield of 70 wt%. In contrast, the degradation of PVC produced only 4.7 wt% liquid products which consisted of C5-C20 hydrocarbons while the degradation of PET surprisingly produced no liquid products. The addition of either PVC or PET to PE decreased the overall liquid product yield, however, it promoted the degradation of PE into low-molecular liquid hydrocarbon products. 

State of liquid Milk white Milk white Milk white Yellow Rufous 

State of liquid Solid and Solid and Light yellow Light yellow Rufous 

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