Abdelkader Chaala

The vacuum pyrolysis of used tires: End-uses for oil and carbon black products

Abstract By vacuum pyrolysis, the rubber portion of used tires is transformed into oil and gas and the carbon black filler is recovered as pyrolytic carbon black (CBP). Several commercial applications for the different products have been investigated and are reported in this article. CBP surface chemistry and activity are similar to those of commercial carbon blacks. Therefore, CBP has the potential to replace commercial carbon black grades in certain rubber applications. CBP was successfully tested as a filler in road pavement. The total pyrolytic oil can be used as a liquid fuel. The oil can also be distilled into different fractions: a light, a middle distillate and a heavy fraction. The light fraction was positively tested as a gasoline additive. Furthermore, this fraction contains valuable chemicals such as d , l -limonene. The middle fraction was successfully tested as a plasticizer in rubbers. The heavy fraction represents a good-quality feedstock for the production of coke and can also be used in road pavements. The pyrolytic gas can be used as a make-up heat source for the pyrolysis process.

Co-pyrolysis of sugarcane bagasse with petroleum residue. Part I: thermogravimetric analysis

Thermal decomposition under nitrogen of sugarcane bagasse, petroleum residue and their blends was studied by thermogravimetry (TG) at different heating rates (10, 20, 40 and 60°C/min). Thermal decomposition kinetic parameters were determined. Sugarcane bagasse pyrolysis was described as the sum of cellulose, hemicellulose, and lignin individual contributions. First order equations were used to determine the bagasse component thermal decomposition kinetics. Activation energies calculated were 235, 105, and 26 kJ/mol for cellulose, hemicellulose and lignin, respectively. Thermal decomposition of petroleum residue can be explained by the additive effect of its three major fractions, following kinetic equation orders of 2.5, 2.3 and 1.5 with activation energies of 100, 180, and 220 kJ/mol, respectively. It has been found that during thermal decomposition of bagasse/petroleum residue mixtures, no significant interaction occurred in the solid phase between the components under the experimental conditions investigated. The kinetic parameters associated with the bagasse/petroleum residue mixture involved the sum of bagasse and petroleum residue individual component kinetic parameters. The information obtained can be used to develop a correlation between the thermogravimetric data and the feedstock composition.

Co-pyrolysis under vacuum of sugar cane bagasse and petroleum residue : Properties of the char and activated char products

Abstract Vacuum pyrolysis of sugar cane bagasse (5.7% moisture) at 500°C and 8 kPa yielded 19.4% charcoal, 34.2% pyrolytic oil, 27.8% water and light organic compounds and 17.6% gases. High surface area (∼1950 m 2 /g) activated carbon was obtained from the chars by steam activation. It was earlier observed that the properties of bagasse-derived pyrolytic oil (biofuel) can be improved by co-pyrolysing the bagasse with petroleum residue. The addition of petroleum residue affects the yields and properties of the pyrolytic char. It was shown by thermogravimetry that the formation of the bagasse char is almost complete when the pyrolysis of the major portion of the petroleum residue occurs. Products from the petroleum residue pyrolysis are deposited on the bagasse char, increasing its yield. According to surface spectroscopic results, the surface of the bagasse char is completely covered when the feedstock concentration of petroleum residue reaches 15%. At this concentration the char yield reaches a maximum (30%). Co-pyrolysis chars yield activated carbon with a lower surface area as compared to bagasse chars. However, since the activated carbons derived from the co-pyrolysis char still have high surface areas and the corresponding pyrolytic oil has good combustion properties, co-pyrolysis of bagasse with petroleum residue might be economically feasible.

Rheological properties of bitumen modified with pyrolytic carbon black

Pyrolytic carbon black (CBp), a by-product of scrap tyre pyrolysis, was blended with a 150200 penetration grade bitumen at concentrations ranging from 5 to 30 wt%. The fundamental rheological properties of standard and modified bitumens as well as their classical characteristics were determined. The interactions between CBp and bitumen components using ESCA, i.r. and u.v. spectroscopy were investigated. The results indicate that pyrolytic carbon black can be used as a filler to reduce the influence of temperature on physical response characteristics of the mixtures. The addition of CBp in amounts of 5–30 wt% of the binder changed the rheological properties of the blends positively.

Vacuum pyrolysis of electric cable wastes

Abstract Metal-free electric cable waste was pyrolyzed at a reduced total pressure of 20 kPa and at a temperature of 450 °C. The two main products were wax (71 wt.%) and pyrolytic carbon black (CBp, 21 wt.%). Pyrolytic wax and CBp were compared with commercial grade materials using FT-IR, ESCA, SIMS and XRD. Similarly to commercial wax, the pyrolytic wax consists mostly of alkyl chains. However, it contains more olefinic groups and the alkyl chains are less branched than commercial wax. The CBp has a high BET surface area (60 m 2 g −1 ), higher than commercial carbon blacks of the N500 series. It contained less than 5 wt.% CaCO 3 , the only inorganic component detected. The surface chemistry of the organic CBp portion was found to be very close to commercial carbon black N539.

SIMS and ESCA characterization of bitumen reinforced with pyrolytic carbon black

Abstract Replacement of commercial carbon black by carbon blacks obtained from tyre pyrolysis (CB p ) would be an interesting commercial application for CB p . Recent work showed that CB p improves the rheological properties of bitumen. This improvement is most probably due to interaction between CB p and asphaltenes, the most polar and heaviest bitumen components. In the present work asphaltenes from commercial and pyrolytic bitumen and a CB p -bitumen mixture were analysed by ESCA, SIMS and i.r. spectroscopy. It was found that the CB p surface is covered with a non-extractable layer of bitumen compounds, especially with aromatic compounds without or with a small concentration of alkyl groups. Asphaltenes from pyrolytic oil have fewer alkyl groups than asphaltenes from commercial oil. Therefore pyrolytic bitumen reinforced with CB p should be an attractive material for road construction.

Chemicals and energy from medical polymer wastes. II. Maleated pyrolysis products in IPP/LLDPE processing

Abstract A way for high valorisation of the waxy product resulted from the pyrolysis of disposable syringes it has been proposed. The waxy product has been chemically modified with maleic anhydride and then has been tested in the processing of IPP/ LLDPE blends on a Haake-Buchler rheometer or on a Werner and Pfeiderer ZSM-30 corotating twin screw extruder. The compatibility of components in the binary IPP/LLDPE and ternary IPP/LLDPE/maleated pyrolysis products from the processing characteristics and DSC results has been appreciated.