Catalytic Cracking of Waxes Produced by the Fast Pyrolysis of Polyolefins

Abstract

The cracking of the waxes obtained in the flash pyrolysis of polypropylene has been studied in laboratory FCC units under the standard conditions in FCC (fluid catalytic cracking) units. The reaction equipment is provided with a riser simulator reactor, and the experiments have been carried out using a commercial equilibrium catalyst, with a catalyst/feed ratio of C/O ) 5.5, in the 500-550 °C range and for contact times between 3 and 12 s. The effect of these operating conditions on the yields of products and on the composition of gas and gasoline lumps has been studied. The results have been compared with those of VGO (vacuum gas oil) cracking, which is the standard FCC feed in refineries, and with those of a mixture of VGO (80 wt %) and waxes (20 wt %).

Acid-catalyzed conversion of chlorinated plastic waste into valuable hydrocarbons over post-use commercial FCC catalysts

“…Problems associated with blockage and limited polymer/catalyst contact within the reactor make continuous processing difficult in fixed-bed reactors. Arandes et al [25] performed a fast pyrolysis of PP to obtain waxes that were subsequently degraded in a riser simulator with a commercial FCC catalyst to improve mass-and heat-transfer constraints. At 500-550 8C, mixtures of waxes with vacuum gasoline oils result in a synergetic effect to produce mostly liquefied petroleum gas and gasoline (42 wt%) with about 4-5 wt% coke content.…”

“…Ultrastable Y (USY) with lower Y framework alumina contents and hence lower unit cell sizes, tend to produce more light alkenes, mainly at the expense of gasoline. A more interesting is that of adding plastic waste into the FCC process, under suitable process conditions with the use of zero value of spent FCC catalysts [21][22][23][24][25] performed on a lab-scale cracking, a large number of polymers can be economically converted into valuable hydrocarbons. Potential concepts have been investigated in our group using a catalytic fluidized-bed reactor to study the product distribution and selectivity of catalytic degradation of several different textiles of post-consumer plastic wastes without PVC mixture previously [26][27][28].…”

Kinetics of the Low Temperature Conversion of Polypropylene to Polypropylene Wax

“…PPW has a wide application field, which can be used for an abrasion-resistant additive of printing inks, for matting surface coating materials, as base materials for pigment preparation, and as an aid in the processing of plastics (lubricants and release agents), and so on. It can also be a feedstock used by the petrochemical industry for obtaining fuels through pyrolysis or catalytic cracking (Arandes et al, 2007). PPW could be obtained by polymerization of propylene using Ziegler-Natta catalysts and pyrolysis of polypropylene (PP).…”

Production of Light Olefins from Polyethylene in a Two-Step Process: Pyrolysis in a Conical Spouted Bed and Downstream High-Temperature Thermal Cracking

“…In previous studies using similar conditions to FCC reactors, it was concluded that cofeeding waxes with vacuum gas oil gives way to an increase in the yield of gasoline (C 5 −C 11 hydrocarbons) and olefins C 2 −C 4 . 26,27 Furthermore, pyrolysis waxes can be co-fed with waxes derived from other processes, such as Fischer−Tropsch, which are also a suitable feedstock for FCC units. 28 This paper studies the upgrading of HDPE pyrolysis waxes in order to obtain light olefins by downstream cracking of the volatile stream (mainly waxes) leaving the CSBR (Figure 1).…”