Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Pastimes : Plastics to Oil - Pyrolysis and Secret Catalysts and Alterna -- Ignore unavailable to you. Want to Upgrade?

To: scion who wrote (12397)	9/10/2011 2:18:49 PM
From: donpat	Read Replies (2) \| Respond to of 53574

Re--Pre melting feeder-- JB follows the leaders!

To: scion who wrote (12397)	9/10/2011 4:44:03 PM
From: scion	Respond to of 53574

CATALYTIC PYROLYSIS OF POLYOLEFINS A Thesis Presented to The Academic Faculty by Ifedinma Ofoma In Partial Fulfillment of the Requirements for the Degree Masters of Science in Chemical & Biomolecular Engineering Georgia Institute of Technology May 2006 CHAPTER 6 CONCLUSIONS AND RECOMMENDATIONS The catalytic pyrolysis of PE and PP was studied by TGA. For this study, the pyrolysis of PE and PP was enhanced by the use of both fresh and equilibrium FCC catalysts. The catalytic activity of a specific FCC formulation was found to increase with reduction in catalyst particle size. The increased surface area of the finer catalyst sample was found to significantly enhance the pyrolysis of PP and PE. While equilibrium catalysts were less effective than the fresh catalysts at desired temperatures, their catalytic activity may be improved by the addition of small amounts of Fresh Fines. In spite of the complex nature of polyolefin degradation, as well as the limitations and assumptions made in kinetic analyses used in this study, the kinetic parameters, Ea and A for the catalysis of PP pyrolysis were obtained from TG data. However, the kinetics estimation by the two different approaches (Isoconversion analysis and the Arrhenius equation) led to some key observations. First, significant deviations were observed in the values of Ea at the different heating rates. Averaging the estimated kinetic parameters over the different heating rates propagates error in both analyses. Secondly, in simulating the TG plots, it was evident that the best fits favored lower weight fractions of catalysts and more so for the non-catalytic reaction, which may be attributed to the simplified mechanism assumed for the complex degradation scheme in polyolefin pyrolysis. Based on these observations, it is recommended that an unconventional approach be used in the kinetic analysis of polyolefin pyrolysis by TG, such as the sample controlled thermal analysis (SCTA) method described in Chapter 3. Although, deviations in the TG characteristics were observed for both the dry mixing and melt mixing methods, the melt-mixing method may still be a more accurate method for TG sample preparation in polyolefin pyrolysis. In this study, the pyrolysis of PP-PCC was achieved at much lower temperatures than the virgin PP. Furthermore, the pyrolysis of the waste PP was only slightly influenced by the FCC catalysts. The decreased activity of the acidic catalysts may be caused by the neutralization of the acidic sites by the original CaCO3 content in the PP-PCC. CaCO3 was found to be more effective than the equilibrium catalysts in lowering Tonset. Overall, the Fresh FCC Fines were the most effective, particularly at 3 wt%; however, its activity on the waste PP was reduced by half compared to the pure PP. It is possible that at much higher catalyst fractions, increased rates of degradation of PP-PCC may be observed. The catalytic pyrolysis of PP in an extruder was modeled using a non-isothermal plug flow reactor model. Based on the kinetic parameters obtained in this study, the reactor model suggests that optimum operating conditions required by the various catalyzed reactions are different. As was shown, the rate of the catalytic reaction is driven by the temperature achieved in the extruder, thus higher yields can be achieved by additional energy input into the system. This may be achieved by the redesign of the screw elements to increase shearing at specific positions along the extruder, consequently increasing conversion of the polymer. Furthermore, the assumptions made in estimating the rate equation may have also contributed in the low yields that were observed. This reactor model may be further investigated using a different estimation of the rate equation. smartech.gatech.edu