Catalytic cracking of polyethylene

T. Isoda, T. Nakahara, K. Kusakabe, and S. Morooka, Catalytic Cracking of Polyethylene-Liquefied Oil over Amorphous Aluminosilicate Catalysts, Energy and Fuels, 12, 1161-1167 (1998). 

Both natural clays and their alnminium oxide pillared analogues have also been tested for the catalytic cracking of polyethylene [49-51]. The clays investigated include mont-morillonite and saponite. They possess a layered structure which can be converted into a two-dimensional network of interconnected micropores by intercalation of molecular moieties. In the case of alnmininm pillared clays, these materials show a mild acidity... 

G. Manos, I. Y. Yusof, N. Papayannakos, and N. H. Gangas, Catalytic cracking of polyethylene over clay catalysts. Comparison with an ultrastable Y zeolite, Ind. Eng. Chem. Res. 40, 2220 (2001). 

R. Lin and R. L. White, Effects of catalyst acidity and HZSM-5 channel volnme on the catalytic cracking of polyethylene, J. Appl. Polym. Sci. 58 1151 (1995). 

R. van Grieken, D. P. Serrano, J. Aguado, R. Garcya and C. Rojo, Thermal and catalytic cracking of polyethylene under mild conditions. Journal of Analytical and Applied Pyrolysis, 58-59, 127-142 (2001). 

Figure 15.1 Schematic showing difference in yields and carbon length distribution for thermal cracking and catalytic cracking. Note different distribution of carbon atoms in liquid fuels made by thermal cracking and catalytic cracking of polyethylene...

Angyal, A., et al., 2009. Catalytic cracking of polyethylene waste in horizontal tube reactor. Polymer Degradation and Stability 94 (10), 1678—1683. 

PET, see Polyethylene terephthalate Petit, Rowland, 524 Petroleum, catalytic cracking of, 100 composition of, 99-100 gasoline from. 99-100 history of, 99 refining of, 99-100 Pharmaceuticals, approval procedure for, 165 origin of, 164 Phenol(s), 599... 

Ethylene is obtained by catalytic cracking of naphtha. It is one of the key petrochemical commodities worldwide used mostly in the production of polyethylene, ethyl benzene, ethylene oxide and others. The consumption of ethylene for the production of alcohols and other surfactant raw materials represents less than 10% of the total end uses of ethylene on a worldwide basis. 

In 1971, LDHs containing different metal cations (such as Mg, Zn, Ni, Cr, Co, Mn and Al) with carbonate as interlayer anions, calcined at 473-723 K and partially or completely chlorinated, were reported to be effective as supports for Ziegler catalysts in the polymerization of olefins [8], with the maximum catalytic activity of polyethylene production observed for Mg/Mn/Al - CO3 LDH calcined at 473 K. Even earher, calcined Mg/Al LDHs were used to support Ce02 for SO removal from the emissions from fluidized catalytic cracking units (FCCU) [9,10]. Some transition metal oxides have also been... 

Figure 17. Comparison of ammonia TPD spectra of fresh REY zeolite with that of coked zeolite, reaction catalytic cracking of oil obtained by the pyrolysis of polyethylene.

According to this concept, Masuda et al. [75] studied the catalytic cracking of the oil coming from a previous thermal pyrolysis step of polyethylene at 450°C in the bench-scale fixed-bed reactor shown in Figure 3.11. The catalysts employed were different zeolite types REY (rare earth exchanged zeolite Y), Ni-REY (nickel and rare earth... 

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 the following sections of this chapter, the catalytic conversion of individual plastics (polyethylene, polypropylene and polystyrene) is first reviewed, followed by a description of the processes developed for the catalytic cracking of plastic and rubber mixtures. Finally, methods based on a combination of thermal and catalytic treatments are considered. However, taking into account that the key factor in the catalytic conversion of plastic wastes is the catalyst itself, we will first describe the main properties of the most widely used catalytic systems for the degradation of polymers. 

Sakata et al.20 have also studied polyethylene degradation over a mesoporous silica catalyst. The material used, called KFS-16, is closely related to MCM-41, although it is prepared by a different method starting from a layered silicate (kanemite). One of the most interesting observations in this work is the PE cracking activity exhibited by KFS-16 in spite of the absence of acid sites (it is a completely silica-based material). Figure 5.10 shows the cumulative volume of liquid products obtained in the thermal and catalytic cracking of PE in a batch... 

IFP Process for 1-Butene from Ethylene. 1-Butene is widely used as a comonomer in the production of polyethylene, accounting for over 107,000 t in 1992 and 40% of the total comonomer used. About 60% of the 1-butene produced comes from steam cracking and fluid catalytic cracker effluents (10). This 1-butene is typically produced from by-product raffinate from methyl tert-huty ether production. The recovery of 1-butene from these streams is typically expensive and requires the use of large plants to be economical. Institut Francais du Petrole (IFP) has developed and patented the Alphabutol process which produces 1-butene by selectively dimerizing ethylene. 

The three isomers constituting n-hutenes are 1-hutene, cis-2-hutene, and trans-2-hutene. This gas mixture is usually obtained from the olefinic C4 fraction of catalytic cracking and steam cracking processes after separation of isobutene (Chapter 2). The mixture of isomers may be used directly for reactions that are common for the three isomers and produce the same intermediates and hence the same products. Alternatively, the mixture may be separated into two streams, one constituted of 1-butene and the other of cis-and trans-2-butene mixture. Each stream produces specific chemicals. Approximately 70% of 1-butene is used as a comonomer with ethylene to produce linear low-density polyethylene (LLDPE). Another use of 1-butene is for the synthesis of butylene oxide. The rest is used with the 2-butenes to produce other chemicals. n-Butene could also be isomerized to isobutene. ... 

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