Copyrolysis of scrap tires with waste lubricant oil

Two different types of scrap tires, passenger car tire (PCT) and truck tire (TT) with waste lubricant oil (WLO) were copyrolyzed in a fixed bed reactor at the temperatures of 550, 650 and 800 °C under nitrogen atmosphere. Copyrolysis products were investigated comparatively. The gaseous products were analyzed by GC–TCD. The physical and chemical properties of copyrolysis oils were characterized by means of ASTM methods, GC–FID, GC–MS, and ¹H NMR. In addition, boiling point distributions of hydrocarbons in copyrolysis oils were determined by using simulated distillation curves in comparison with commercial diesel. An increase in the temperature had no effect on the product distributions of copyrolysis and the composition of copyrolysis oils. However, the types of scrap tires strongly effected the product distributions and compositions of copyrolysis oils. Copyrolysis of PCT/WLO produced less amount of liquid and more amount of solid residue than that of copyrolysis of TT/WLO. However, the naphtha and aromatic content in oils from copyrolysis of PCT/WLO was found more than that of TT/WLO. The amount of aromatic content in copyrolysis oils found to be less than that of scrap tire derived oils. By comparing the copyrolysis oils with commercial diesel, copyrolysis oils contained lighter fraction than that of commercial diesel whereas the specific gravities and viscosities of copyrolysis oils were higher than that of commercial diesel.     

Copyrolysis of scrap tires with waste lubricant oil

Two different types of scrap tires, passenger car tire (PCT) and truck tire (TT) with waste lubricant oil (WLO) were copyrolyzed in a fixed bed reactor at the temperatures of 550, 650 and 800 °C under nitrogen atmosphere. Copyrolysis products were investigated comparatively. The gaseous products were analyzed by GC–TCD. The physical and chemical properties of copyrolysis oils were characterized by means of ASTM methods, GC–FID, GC–MS, and ¹H NMR. In addition, boiling point distributions of hydrocarbons in copyrolysis oils were determined by using simulated distillation curves in comparison with commercial diesel. An increase in the temperature had no effect on the product distributions of copyrolysis and the composition of copyrolysis oils. However, the types of scrap tires strongly effected the product distributions and compositions of copyrolysis oils. Copyrolysis of PCT/WLO produced less amount of liquid and more amount of solid residue than that of copyrolysis of TT/WLO. However, the naphtha and aromatic content in oils from copyrolysis of PCT/WLO was found more than that of TT/WLO. The amount of aromatic content in copyrolysis oils found to be less than that of scrap tire derived oils. By comparing the copyrolysis oils with commercial diesel, copyrolysis oils contained lighter fraction than that of commercial diesel whereas the specific gravities and viscosities of copyrolysis oils were higher than that of commercial diesel.     

Investigation into the removal of sulfur from tire derived fuel by pyrolysis

There is growing interest in the use of scrap tires as both a fuel and a feed material for petroleum feedstocks due to their abundance and their chemical composition. However, the sulfur content of scrap tires is a potential obstacle to scrap tires utilization as a fuel. In this paper, the partitioning of sulfur was investigated from the two major pyrolytic products from passenger car tires, liquid oils and solid chars, and the potential of producing a low sulfur char for fuel applications. The removal of sulfur during tire pyrolysis offers the greatest potential for the separation of sulfur products from the evolved gases and vapors. The influences of heating rate and pyrolysis temperature were investigated from 325 to 1000 °C, a range where substantial devolatilization occurs. The pyrolysis char and derived oil were analyzed for sulfur, and compared to the original parent sulfur content in tire derived fuel (TDF) samples. The results of sulfur determination verify that the overall desulfurization from the pyrolysis reaction is essentially unaffected by the heating rate but is affected by the ultimate pyrolysis temperature.     

废弃轮胎的热解回收技术

从反应温度、反应时间、催化剂等热解条件对废弃轮胎热解产品产量的影响、热解的产物分析及其应用、废弃轮胎中硫的迁移等方面进行了详细论述。指出反应温度是轮胎热解的主影响因素。热解后,一般得到质量分数为10%～30%的气体、38%～55%的油相产物及33%～38%的固相产物,这些产物均具有较高的热值,可以作为燃料。此外,还可以分离回收液相中的具有较高附加值的化学物质;固相产物以炭黑为主,经处理后可以作为炭黑回用或吸附剂使用。同时还对废弃轮胎热解产物中硫的转化分布进行了讨论。最后对废弃轮胎的其他处理回收技术进行了展望。     

废轮胎热解炭黑的研究进展

热解发黑作为废轮胎热解的关键产物,其品质较差,达不到使用要求,而且会对环境造成二次污染.主要介绍了废轮胎热解炭黑常用的分析表征方法,对热解炭黑的活化改性及再利用途径进行综述,旨在提高其利用价值.     

Supercritical extraction of scrap tire with different solvents and the effect of tire oil on the supercritical extraction of coal

Scrap tires are a growing environmental problem because they are not biodegradable. In this investigation, supercritical extraction of scrap tire and co-processing of coal with tire oil were studied. In the first stage, tires were extracted at 400 °C with a number of different solvents. The effects of the hydrocarbon and polar solvents used under the supercritical extraction conditions on the conversion and oil product of tire were determined, and it was observed that all volatile organic material of the scrap tire was converted to the liquid or gas product. In the second stage, coal and supercritical extracted tire oil (SCETO) samples were extracted with different solvents using various tire oil/coal ratios. In general, the use of tire oil generated an improvement for coal conversion. Further, the oil yield was higher than those of coal alone runs. The SCETOs were characterized using spectroscopic (FTIR) and chromatographic analytical techniques (GC–MS). GC–MS, and FTIR results showed that the oils are mainly comprised of alkyl aromatic species. A significant amount of alkyl-substituted phenol compounds was also found to be present in the oils.     

SOME OBSERVATIONS FROM STUDIES OF RF PLASMA PYROLYSIS OF WASTE TIRES

Pyrolysis treatment of waste tires was studied in a capacitively-coupled radio frequency (RF) plasma reactor. Using RF input power between 1600 and 2000 W and a reactor pressure between 3000 and 8000 Pa, a reactive plasma environment with a temperature between 1200 and 1800 K can be reached. Under these conditions, pyrolysis experiments with tire powder showed that two product streams were obtained: a combustible gas and a pyrolytic char. The main gaseous components were H₂, CO, and CH₄. When adopting double sets of electrodes in this plasma reactor, the gas yield and concentrations of H₂ and CO can be enhanced. The energy utilization efficiency of this RF plasma pyrolysis reactor system was also analyzed.     

Pyrolysis of tetra pack in municipal solid waste

The pyrolysis of tetra pack in nitrogen was investigated with a thermogravimetric analysis (TGA) reaction system. The pyrolysis kinetics experiments for the tetra pack and its main components (kraft paper and low‐density poly(ethene) (LDPE)) were carried out at heating rates (β) of 5.2, 12.8, 21.8 K min^?1. The results indicated that the one‐reaction model and two‐reaction model could be used to describe the pyrolysis of LDPE and kraft paper respectively. The total reaction rate of tetra pack can be expressed by the summation of the individual class of LDPE and kraft paper by multiplying the weighting factors. The pyrolysis products experiments were carried out at a constant heating rate of 5.2 K min^?1. The gaseous products were collected at room temperature (298 K) and analyzed by gas chromatography (GC). The residues were collected at some significant pyrolysis reaction temperatures and analyzed by an elemental analyzer (EA) and X‐ray powdered diffraction (XRPD). The accumulated masses and the instantaneous concentrations of gaseous products were obtained under the experimental conditions. The major gaseous products included non‐hydrocarbons (CO₂, CO, and H₂O) and hydrocarbons (C_1–5). In the XRPD analysis, the results indicated that pure aluminum foil could be obtained from the final residues. The proposed model may be supported by the pyrolysis mechanisms with product distribution. © 2001 Society of Chemical Industry     

Evaluation of pyrolytic oil from used tires and natural rubber (Hevea brasiliensis)

The pyrolysis of used tires, UT, and natural rubber (Hevea brasiliensis), NR obtained from Nigerian NIG800 clonal rubber tree, was performed and the effects of process conditions on product yield were investigated. An optimum yield was attained at operating temperature of 600°C, a heating rate of 15°C?min^?1, for a feed size of 6?mm. The UT and NR gave maximum pyrolytic oil yield of 34.40 and 75.93?wt%, respectively. The pyrolytic oil was characterized using Fourier transform infrared, nuclear magnetic resonance, and gas chromatography–mass spectrometry (GC–MS). Results obtained reveal the pyrolytic oil to be a complex mixture, mainly of aliphatic and aromatic compounds, which can serve as feedstock for industrial application. Nevertheless, a comparative evaluation of the physical and chemical properties of the UT and NR pyrolytic oil showed that NR had hydrocarbon composition of 80% aliphatics, 12% aromatics (with less than 2% polycyclic aromatic hydrocarbon concentration). However, the UT pyrolytic oil had 42% aliphatic and 34% aromatic compounds (with polycyclic aromatic hydrocarbons concentrations of 18%). Also, NR pyrolytic oil had better physical properties such as density, viscosity, flash point, pour point, and higher heating value than that produced from UT in this study, and comparable with that of commercial diesel. Moreover, sulfur content, which is a limiting factor in the direct combustion of UT pyrolytic liquid, was absent in NR pyrolytic oil. Hence, it is technologically feasible for NR from H. brasiliensis to be a suitable source of pyrolytic oil than UT.     

Effect of heating rate on pyrolysis of low-grade pyrolytic oil

The low-grade pyrolytic oil produced from pyrolysis of municipal plastic waste in a commercial rotary kiln reaction system cannot be an acceptable fuel oil due to its low quality. Thus, the degradation of pyrolytic oil was conducted in a bench scale batch reactor, which was done by two experiment conditions of high heating rate (about 7 °C/min) and low heating rate (1.5–3.6 °C/min) up to 420 °C of reaction temperature. The characteristics of raw pyrolytic oil were examined and also the characteristics of products obtained by different heating rates were compared. Raw pyrolytic oil had higher H/C ratio and higher heating value than commercial oils, and also its peak range in GC analysis showed wide distribution including all the range of gasoline, kerosene and diesel. In the upgrading of pyrolytic oil, cumulative amount profile of product oil, as a function of reaction time, was similar in shape to the degradation temperature profile. All product oils obtained by different degradation temperature had higher H/C ratio and slightly higher heating value than those of raw pyrolytic oil. Also, the characteristics of product oils were influenced by heating rate and reaction temperature.     

Comparative studies of oil compositions produced from sawdust,rice husk,lignin and cellulose by hydrothermal treatment

The objective of this study is to investigate the distribution of products, i.e. liquid, gas and solid from wood (sawdust) and non-wood biomass (rice husk), and major biomass components, i.e. lignin, cellulose produced by hydrothermal treatment (280 °C for 15 min) and analysis of liquid hydrocarbons (oils) for the differences in the hydrocarbon composition with respect to feed material. Cellulose showed the highest conversion among the four samples investigated in the present study. Sawdust and rice husk has almost similar conversions. Liquid products were recovered with various solvents (ether, acetone, and ethyl acetate) and analyzed by GC–MS. The oil (ether extract) from the hydrothermal treatment of cellulose consisted of furan derivatives whereas lignin-derived oil contained phenolic compounds. The compositions of oils (ether extract) from sawdust and rice husk contained both phenolic compounds and furans, however phenolic compounds were dominant. Rice husk derived oil consists of more benzenediols than sawdust derived oil. The volatility distribution of oxygenated hydrocarbons were carried out by C-NP gram and it showed that the majority of oxygenated hydrocarbons from sawdust, rice husk and lignin were distributed at n-C₁₁, whereas they were distributed at n-C₈ and n-C₁₀ in cellulose-derived oil. The gaseous products were carbon dioxide, carbon monoxide, methane in sawdust, rice husk, lignin and cellulose. In addition to this, ethylene, ethane and propane were observed for sawdust, rice husk and lignin. The major gas product was carbon dioxide for all samples.     

Characterization of naphtha and carbon black obtained by vacuum pyrolysis of polyisoprene rubber

Pure polyisoprene and a commercial rubber sample containing 52% polyisoprene and 31% carbon black were pyrolysed at 500°C and at a total pressure varying between 0.8 and 28.0 kPa. The yields of gas, oil and pyrolytic carbon black (CB_P) changed little with the pyrolysis pressure. However, the oil composition and the CB_P characteristics depended considerably on the pyrolysis pressure. For example, the amount of dl-limonene, a valuable compound in the naphtha fraction, decreased with increasing pyrolysis pressure. The CB_P and the commercial carbon black initially present in the rubber sample were analysed by ESCA, SIMS and SEM. With decreasing pyrolysis pressure the surface chemistry of the CB_P became similar to that of the commercial carbon black initially present in the rubber. Therefore, rubber pyrolysis should be performed at low pressures in order to obtain products with a higher commercial value.     

Production of pyrolytic oils by catalytic pyrolysis of Malaysian refuse-derived fuels in continuously stirred batch reactor

Malaysian refuse derived fuels (RDF) as valuable fraction of waste recycling were pyrolyzed in continuously stirred batch rig at 450 °C in the presence and absence of catalysts. Different types of catalysts were used for upgrading both quantity and quality of pyrolysis products: Y-zeolite, equilibrium FCC, ZSM-5, Ni-Mo-catalyst, Co-Mo-catalyst, silica-alumina and alumina. Gas-chromatography, Fourier-transformed infrared spectroscopy, X-ray spectroscopy and other standardized methods were used for the identification of product. RDF pyrolysis has produced gases with yields of 15.7-27.8%, pyrolytic oils of 9.8-17.8% and water (9.2-12.8%) depending on the types of applied catalyst. Data showed that the volatile fraction (both gas and pyrolytic oils) slightly increased with the catalyst, especially for Y-zeolite and ZSM-5. Gases consisted of CO, CO₂, hydrogen and hydrocarbons. Main chemical compounds, such as aromatic, branched and non-branched in pyrolytic oils have been affected by catalysts, e.g. isomerization of main carbon frame and aromatization have been shown increasing in yields especially when Y-zeolite and ZSM-5 were applied. The phenol, benzene 1,3-diol and methyl-phenol content of pyrolytic oil obtained from non-catalytic pyrolysis decreased at 45.0%, 40.9% and 38.0%, respectively in the presence of Y-zeolite and at 39.4%, 36.9% and 26.9% over Co-Mo-catalyst compared to the catalyst free pyrolysis, respectively. Sulphur, nitrogen and chlorine were found as contaminants in pyrolytic oils, but their contaminants concentration could be significantly decreased by the use of catalysts. The activity of catalysts in the decrease of impurity followed the order of Ni-Mo-cat. > Co-Mo-cat. > Y-zeolite > FCC > ZSM-5 > Al₂O₃/SiO₂ > Al₂O₃. According to EDXRFS analysis, char consisted of impurities such as Ca, Ti, Fe, Cu, Zn and Pb elements.     

Rubber waste processing by high-temperature pyrolysis

The high-temperature pyrolysis of thermosetting plastics (high-density rubber, tires, and rubber mixtures including cords) leads to the formation of a liquid fraction, a noncondensable portion of pyrolytic gas, and solid residues. The pyrolysis of scrap rubber is characterized by high ecological and economic characteristics.     

废橡胶热裂解技术现状及发展方向

废橡胶是继白色污染之后又一大污染——黑色污染,是世界性的又一大难题,其中比重最大的就是废轮胎,世界各国尤其是发达国家纷纷致力于轮胎的回收利用研究.特别是其回收产品的再利用:一方面解决资源的短缺;另一方面获取较高的经济价值.经长期的探究,人们发现与翻新、制造胶粉和再生胶、作沥青填料、直接作为燃料焚烧等处理方法相比,热裂解...     

Acid-base method for the demineralization of pyrolytic carbon black

The carbon black material used as reinforcing filler in tires was recovered by vacuum pyrolysis at a temperature of 500°C and a total pressure of 20 kPa. The pyrolytic carbon black obtained (CBp) was contamined by various additives of the original tire. Contaminants were also produced by chemical reactions occurring in the pyrolysis reactor. The contamination is reflected by the high content of ash and gritty materials (coke) present in the CBp. A characterization of the recovered carbon black was performed and a possible reduction of the ash content by sulfuric acid and sodium hydroxide treatment was investigated. The variables which were studied included the ratio of reactant to carbon black, the reactant concentration, the treatment temperature and the reaction time. Properties of the commercial carbon black filler grade N539 were compared to those of the CBp recovered before and after the demineralization treatment.     

Pyrolysis of polyolefins in high-boiling solvents

The pyrolysis of polyethylene and polypropylene in vacuum residue and coal-tar pitch solvents was studied in a batch reactor at atmospheric pressure in a temperature range of 380–420°C. Aliphatic hydrocarbons and C₅–C₃₂ normal olefins and isoolefins were the main pyrolysis products of the polyolefins and vacuum residue, which also underwent thermal degradation at these temperatures. The total conversion of a polypropylene-vacuum residue mixture into gaseous and distillate products was nearly additive; upon the pyrolysis of polypropylene in pitch and of polyethylene in vacuum residue and pitch, the yield of distillate products decreased and the paraffin/olefin ratio in these products increased. The observed regularities were explained by hydrogen transfer from the solvents to the intermediate radical products of the thermal decomposition of polymer chains. The reactions of the resulting of olefins with the solvents can also occur to a lesser degree. The greatest deviations from additivity were observed in the pyrolysis of polyethylene in the solvents used.     

Effect of ultrafine zinc borate on the smoke suppression and toxicity reduction of a low‐density polyethylene/intumescent flame‐retardant system

The production of smoke, carbon monoxide (CO), and carbon dioxide (CO₂) were investigated with cone calorimetry testing when low‐density polyethylene (LDPE), LDPE treated with an intumescent flame retardant (IFR), and LDPE treated with an IFR and ultrafine zinc borate (UZB) combusted under irradiation. The results of the testing showed that UZB could depress smoke production and reduce the amount of CO and CO₂. The components of the pyrolytic gas and its contents were identified and measured with pyrolysis–gas chromatography/mass spectrometry (Py–GC–MS) when LDPE, LDPE/IFR, and LDPE/IFR/UZB were pyrolyzed at 400°C for 20 s. The Py–GC–MS results implied that UZB had an important influence on the components and contents of the pyrolytic gas of LDPE/IFR. UZB mechanisms of smoke suppression and toxicity reduction with respect to LDPE/IFR are proposed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermal conductivity of MgO-C refractory ceramics: Effects of pyrolytic liquid and pyrolytic carbon black obtained from waste tire

In the present study, thermal conductivity and mechanical properties of MgO-C refractory ceramic bricks were investigated. Pyrolytic liquid and pyrolytic carbon black obtained from pyrolysis of waste tires were used as a resin and carbon source, respectively. The pyrolysis of the tires was conducted in a fixed bed reactor at the temperature of 500?°C with a 15?°C/min heating rate under nitrogen flow (0.5?lt/min). Before using in MgO-C refractory ceramic blends, pyrolytic products were purified with the acidic extraction methods which resulted in 61and 66?wt%. decreases in sulfur and ash contents in pyrolytic carbon, respectively. After this treatment of pyrolytic liquid, the sulfur content was reduced by 24?wt%. Eight different blends of MgO-C refractory ceramics consisting of different pyrolytic product contents were prepared, pressed, and tempered at 250?°C, and then characterized in terms of porosity, thermal conductivity, and density. The mechanical behavior of the samples was tested using a three-point bending test. Archimedes test was employed to determine the porosity and density. Surface properties of the bricks were analyzed by scanning electron microscopy (SEM). The obtained results were compared with a reference consisting of graphite and resin. The results revealed that mechanical and thermal properties of the developed bricks were highly sensitive to the porosity and the carbon source as well as the type of binder.     

ESCA characterization of commercial carbon blacks and of carbon blacks from vacuum pyrolysis of used tires

Pyrolytic carbon blacks (CB_p) were obtained by vacuum pyrolysis of used tires in a batch reactor at a total pressure ranging from 0.3 to 20.0 kPa, and temperatures ranging from 420 to 700°C. CB_p differ from commercial carbon blacks used initially in the tire fabrication. A series of commercial carbon blacks with different surface areas and structures and CB_p obtained under different pyrolysis conditions were characterized using ESCA and SEM techniques to investigate the effect of the pyrolysis conditions on the chemical nature of the surface of CB_p.