Study of a two steps process for the valorization of PVC-containing wastes

Published online 27 November 2012The presence of organic compounds in wastes, namely polymer based compounds, is considered a potential relevant source of energy. However, the presence of polyvinyl chloride (PVC) in their composition, causes recycling problems when a thermal process is considered for the wastes treatment [1] preventing its use on processes which the main goal is the energy recovery (Zevenhoven et al. in Fuel 81:507–510, 2002; Kim in Waste Manag 21:609–616, 2001). A possible solution should consider a first step for chlorine removal, through a pyrolysis process previously to a subsequent thermal treatment, for energetic valorization. The present work assesses a possible process for treating PVC-containing wastes in an environmentally friendly way. It is based on the effective de-chlorination of PVC-containing wastes through a pyrolysis process at low temperature before the carbonaceous residue (chlorine free fraction) being subjected to a subsequent thermal treatment for energetic valorization with the production of a synthesis gas (syngas). In the end of the process concentrated hydrochloric acid or other chlorine solutions and a syngas, with high energetic potential are obtained. The synthesis gas produced can be used in turbines or gas engines, replacing the gases obtained from fossil non-renewable resources. The validation of the proposed treatment of PVC-containing wastes in pilot scale has also been performed

Liquefaction of Municipal Waste Plastics over Acidic and Nonacidic Catalysts

This chapter contains sections titled: Introduction Catalytic Liquefaction of MWP Conclusions References. © 2006 John Wiley & Sons, Ltd

Utilization of products obtained from copyrolysis of oil shale and plastic

The main objective of the present study was to investigate pyrolysis of oil shale with polyethylene, in terms of yields and properties of the products obtained. A detailed characterization of gas, oil and char from copyrolysis is presented. Although no synergetic effect on the product yield was observed during the copyrolysis, the addition of polyethylene (PE) to oil shale improved fuel properties of shale oil leading to a decrease in the oxygen content of shale oil. As the ratio of polyethylene increased in the blends, the amount of aliphatic compounds in tars increased while that of polar compounds decreased. In addition, the presence of PE in the blend improved the composition of pyrolysis gas leading to an increase in combustible gases. The production of activated carbon from char obtained from oil shale/polyethylene (1/1) was also carried out. Although the surface area of activated carbon was smaller than that of obtained from lignocellulosic materials, it had a notable adsorption capacity for Cr(VI) (55.25 mg/g). © 2009 Estonian Academy Publishers

Conversion of polymers to fuels in a refinery stream

WOS: 000172733200017The purpose of this study was to investigate the processability of LDPE, PP, PVC/LDPE and PVC/PP in the hydrocracking unit of a refinery. For this, LDPE or PP has been added to vacuum gas oil (VGO). The blends were hydrocracked over different catalysts using a batch autoclave at 425-450 degreesC under hydrogen atmosphere. The catalysts used were HZSM-5, Cobalt loaded active carbon (Co-Ac) and DHC-8 (commercial silica-alumina catalyst). Addition of polymer to VGO affected the cracking of VGO, leading to a decrease in the gas yield and an increase in the liquid yield. In hydrocracking over HZSM-5, the product distribution was similar for two blends. HZSM-5 gave higher gas yields than the other catalysts. When using Co-Ac and DHC-8 catalysts, the gas and liquid yields depend on the polymer type as well as temperature. In the case of the PVC-containing blends (PVC/PP/VGO or PVC/PE/VGO), the blends were firstly dechlorinated at 350 degreesC. Then the dechlorinated mixture was hydrocracked in the 400-450 degreesC range in the presence of DHC-8. HCl evolved by degradation of PVC during the dechlorination step partially degraded PE and PP and these predegraded polymers were more easily cracked in the hydrocracking step. In addition, we observed the effect of polyene formed from the PVC degradation residue on the thermal hydrocracking. The chlorine compounds in the hydrocracked feed affected the catalytic activity of the catalysts. (C) 2001 Elsevier Science Ltd. All rights reserved

Iridoids from Scabiosa atropurpurea L. subsp. maritima Arc. (L.)

[No abstract available

Liquefaction of municipal waste plastics in VGO over acidic and non-acidic catalysts

WOS: 000180441700007Co-processing of municipal waste plastics (MWP) with vacuum gas oil (VGO) over HZSM-5, DHC-8 (commercial silica-alumina catalyst) and cobalt loaded active carbon catalyst has been comparatively studied. Co-processing experiments were carried out under hydrogen atmosphere at temperatures between 425 and 450 T. The composition, sulphur and chlorine amount of liquid products were determined. The product distribution and the composition of liquids were changed depending upon the temperature and the catalyst type. As expected temperature led to increase in cracking activity of catalysts. DHC-8 and HZSM-5 showed substantially different activities in co-processing due to the difference in their acidity. HZSM-5 gave highest gas yield at all temperatures and highest liquid yield (38.3) at low temperature. Although Co-AC was a neutral catalyst, it showed the cracking activity as well as HZSM-5 and more than DHC-8. No chlorine compound was observed in liquid products. The sulphur amount in liquid products varied with the catalyst type. Although HZSM-5 showed good cracking activity at low temperatures, it gave the liquid product containing highest sulphur amount. By considering both the quantity and quality of liquid fuel obtained from co-processing, it may be concluded that Co-AC gave the best result in the co-processing of the MWP/VGO blend. To observe the effect of metal type loaded on active carbon on catalyst activity, a series of co-processing experiments was also carried out. (C) 2002 Published by Elsevier Science Ltd

Conversion of plastics/HVGO mixtures to fuels by two-step processing

WOS: 000170862600002A blend containing 20 wt.% low density polyethylene (PE) and 5 wt.% polyvinylchloride (PVC) in heavy vacuum gas oil was pyrolyzed at 623 K (dechlorination step). This mixture was then thermally and catalytically cracked in the presence of hydrogen at 673-723 K in a batch reactor (hydrocracking step). The liquid products from hydrocracking contained no chlorine compounds although the chlorine amount in the dechlorinated mixture was 700 ppm. Experiments have shown that the dechlorination step and the temperature had great effect on the product distribution from the hydrocracking step. It was observed that the dechlorination step led to both degradation of PE and dechlorination of PVC and that PE could be completely cracked with/without a catalyst by hydrocracking even though at 673 K. The use of a catalyst decreased the gas yield and led to an increase in coke yield at 723 K. The effect of the catalyst on the boiling point range of liquid product obtained from hydrocracking depended on the reaction temperature. The chlorine compounds in dechlorinated mixture affected the catalytic activity of the catalyst especially at 723 K. 75% and 55% of the liquid products obtained at 723 K with and without a catalyst, respectively, were hydrocarbons having boiling points ranging from 323 to 473 K. (C) 2001 Elsevier Science B.V. All rights reserved