Pyrolysis Of Polyvinyl Chloride Research Articles

A high performance silicon/carbon composite anode with carbon nanofiber for lithium-ion batteries

The electrochemical performance of a composite of nano-Si powder and a pyrolytic carbon of polyvinyl chloride (PVC) with carbon nanofiber (CNF) was examined as an anode for lithium-ion batteries. CNF was incorporated into the composite by two methods; direct mixing of CNF with the nano-Si powder coated with carbon produced by pyrolysis of PVC (referred to as Si/C/CNF-1) and mixing of CNF, nano-Si powder, and PVC with subsequent firing (referred to as Si/C/CNF-2). The external Brunauer–Emmett–Teller (BET) surface area of Si/C/CNF-1 was comparable to that of Si/C/CNF-2. The micropore BET surface area of Si/C/CNF-2 (73.86 m 2 g −1) was extremely higher than that of Si/C/CNF-1 (0.74 m 2 g −1). The composites prepared by both methods exhibited high capacity and excellent cycling stability for lithium insertion and extraction. A capacity of more than 900 mA h g −1 was maintained after 30 cycles. The coulombic efficiency of the first cycle for Si/C/CNF-1 was as low as 53%, compared with 73% for Si/C/CNF-2. Impedance analysis of cells containing these anode materials suggested that the charge transfer resistance for Si/C/CNF-1 was not changed by cycling, but that Si/C/CNF-2 had high charge transfer resistance after cycling. A composite electrode prepared by mixing Si/C/CNF-2 and CNF exhibited a high reversible capacity at high rate, excellent cycling performance, and a high coulombic efficiency during the first lithium insertion and extraction cycles.

Upgrading of Pyrolyzed Oil Derived from Pyrolysis of Polyvinyl Chloride and Polypropylene

Upgrading of Pyrolyzed Oil Derived from Pyrolysis of Polyvinyl Chloride and Polypropylene

Pyrolysis of Polyvinyl Chloride (PVC)-Containing Mixed Plastic Wastes for Recovery of Hydrocarbons

The pyrolysis of mixed plastic waste (high-density polyethylene, polypropylene, polystyrene, and polyvinyl chloride) using a long residence time (25 min) in a horizontal tube reactor at 530 °C has been investigated. The reactor was fitted with atmospheric and vacuum distillation columns, so that the pyrolysis products could be separated into heavy oil, light oil, gasoline, and gases. The effect of the polyvinyl chloride (PVC) concentration on the properties of products was investigated. Products were characterized using gas chromatography, infrared spectroscopy, and energy-dispersive X-ray spectroscopy, whereas some other standardized methods were used to determine the main properties of hydrocarbons. Results show that the mixed plastic waste samples could be converted into gases, gasoline, and light oil with yields of 36.9−59.6% depending upon the composition of feed polymers, and the conversion of decomposition is significantly increased with an increasing concentration of PVC. It was found that product...

Magnetic properties of carbon materials prepared from polyvinyl chloride

Carbon materials were prepared by pyrolysis of polyvinyl chloride (PVC). Although PVC powder exhibited diamagnetic behavior, the carbon material prepared by pyrolysis at 1073 K exhibits paramagnetic behavior, while that prepared by pyrolysis at 1273 K exhibited ferromagnetic behavior. X-ray diffraction and Fourier transform infrared spectrometry studies revealed that the paramagnetic and ferromagnetic carbon materials consist of nanometer scale graphitelike grains within a highly disordered carbon matrix.

TG-FTIR analysis of PVC thermal degradation and HCl removal

The pyrolysis of polyvinyl chloride (PVC) was qualitatively analyzed by TG-FTIR, and HCl removal efficiency of Ca-based additives were semi-quantitatively studied also by means of TG-FTIR. Additionally, the thermodynamic equilibrium modeling was also carried out to understand the formation of HCl from PVC and from mixtures of PVC with different additives. Experimental results showed that the pyrolysis of PVC took place in two steps accompanied by the release of HCl and hydrocarbon, respectively. Almost all Cl transformed to HCl, and hardly any other kinds of Cl compounds were detected. The addition of Ca-based additives extended the second weight loss step of PVC, but they did not affect the release time when the maximum HCl concentration appeared. The maximum HCl concentration decreased according to the increase of additive amount, that is to say, the HCl removal efficiency increased as the Ca/Cl molar ratio increased, however when the Ca/Cl ratio increased to a certain value, the increase of HCl removal efficiency was not proportional to the increase of additive amount. For different additives, different Ca/Cl ratios should be chosen based on the cost, HCl removal efficiency and utilization efficiency of additive.

Surface-modified meso-carbon microbeads anode for dry polymer lithium-ion batteries

A high-anode performance for dry polymer lithium-ion batteries was obtained in the surface-modified meso-carbon microbeads (MCMB). MCMB and polyvinylchloride (PVC) mixture was heated at 700 °C for 6 h under inert atmosphere. By this treatment, the surface of MCMB is covered with low-crystalline carbon material derived from PVC pyrolysis. The surface-modified MCMB electrode applied to dry polymer electrolytes shows a reversible capacity of 300 mAh g −1, which is comparable to those obtained in the liquid electrolyte systems.

石炭とプラスチックのコプロセッシングに及ぼすＰＶＣの影響

The coprocessing with coal is one of the beneficial technologies to convert waste plastics into alterna-tive liquid hydrocarbon for fuel oil and chemical feedstock. The waste plastics having high H/C ratio are expected to play the role of hydrogen source. On the other hand, the waste plastics include chlorine-contain-ing plastic such as polyvinyl chloride (PVC). Hydrogen chloride generated from pyrolysis of PVC causes the problems such as the corrosion of equipment. In the coprocessing reaction, it is expected that the hydrogen chloride is captured by the minerals in coal.In this paper, the influence of PVC on the coprocessing with Wyoming subbituminous coal and the mixture of high density polyethylene, polypropylene, polystyrene, and PVC was investigated under decalin solvent.A part of hydrogen chloride generated from PVC was fixed as chlorides by the minerals in coal, but the rest formed chlorinated organic compounds. These reactions occured competitively. When a sufficient amount of hydrogen chloride was not captured, the chain reactions of polymer radicals were inhibited by chlorine radical. This inhibitation resulted in the increase of heavy oil yield. To avoid it, the optimization of the raito of coal and plastics was desired.

Development of a catalytic dehalogenation (Cl, Br) process for municipal waste plastic-derived oil

Dehalogenation is a key technology in the feedstock recycling of mixed halogenated waste plastics. In this study, two different methods were used to clarify the effectiveness of our proposed catalytic dehalogenation process using various carbon composites of iron oxides and calcium carbonate as the catalyst/sorbent. The first approach (a two-step process) was to develop a process for the thermal degradation of mixed halogenated waste plastics, and also develop dehalogenation catalysts for the catalytic dehydrochlorination of organic chlorine compounds from mixed plastic-derived oil containing polyvinyl chloride (PVC) using a fixed-bed flow-type reactor. The second approach (a single-step process) was the simultaneous degradation and dehalogenation of chlorinated (PVC) and brominated (plastic containing brominated flame retardant, HIPS–Br) mixed plastics into halogen-free liquid products. We report on a catalytic dehalogenation process for the chlorinated and brominated organic compounds formed by the pyrolysis of PVC and brominated flame retardant (HIPS–Br) mixed waste plastics [(polyethylene (PE), polypropylene (PP), and polystyrene (PS)], and also other plastics. During dehydrohalogenation, the iron- and calcium-based catalysts were transformed into their corresponding halides, which are also very active in the dehydrohalogenation of organic halogenated compounds. The halogen-free plastic-derived oil (PDO) can be used as a fuel oil or feedstock in refineries.

Formation behavior of PCDD/Fs in PVC pyrolysis with copper oxide

Formation and decomposition behaviors of PCDD/Fs during pyrolysis of polyvinyl chloride (PVC) with CuO have been investigated. These reactions proceed simultaneously, and the rate of decomposition exceeds that of formation with further retention. More 2,3,7,8-TCDD is formed when the dechlorination of PCDD/Fs proceeds significantly. Homologue profile patterns of PCDD/Fs show that the fractions of O8CDD and H6CDFs are relatively larger within PCDDs and PCDFs, respectively. Extremely large amounts of PCDD/Fs are obtained with the long retention time at 200 °C. The formation of PCDD/Fs deceases drastically with increase in the molar ratio of CuO/PVC. The acceptability of thermodynamic calculations on the formation of PCDD/Fs is also investigated. The thermodynamic calculated tendency of the effect of oxygen on the formation of PCDD/Fs agrees well with the experimental results, although absolute values of the amount of PCDD/Fs are much different.

Catalytic pyrolysis of polyvinylchloride in the presence of metal chloride

Catalytic pyrolysis of polyvinylchloride in the presence of metal chloride

Preparation of carbon-coated transition metal particles from mixtures of metal oxide and polyvinylchloride

Carbon-coated α-iron particles ca 100 mm in diameter were prepared through a simple heat-treatment of mixtures of Fe 3O 4 and polyvinylchloride (PVC) at 1000°C in an Ar flow. After HCl treatment of the particles to remove iron and iron compounds, hollow carbon particles were seen under the scanning electron microscope. According to thermogravimetric analysis of the Fe 3O 4–PVC mixture, the formation of carbon-coated α-iron particles proceeds in four steps with weight loss, the first two steps being due to the pyrolysis and carbonization of PVC, and the last two to the reduction of Fe 3O 4 to α-Fe. Using the other transition metal oxides, NiO, CoO and Cu 2O, carbon-coated respective metal particles were also prepared using the same procedure.

Two‐Stage pyrolysis model of PVC

AbstractThe pyrolysis of polyvinyl chloride (PVC) was examined with a thermal gravimetric analyzer (TGA). The experiments were carried out over the temperature range of 400‐800 K at three heating rates of 1, 2, and 5.5 K/min and in a nitrogen atmosphere. The results indicate that the entire process of PVC pyrolysis under the experimental conditions of this investigation consists of two distinct pyrolysis stages, namely, the thermal dehydrochlorination and the breakdown of the intermediate products produced after the dehydrochlorination stage. The corresponding activation energy, pre‐exponential factor, and reaction order were determined. A two‐stage pyrolysis model, which is composed of four reactions including a number of independent, consecutive and competitive reactions with volatiles and solid products, was developed. This kinetic model gives good agreement with the experimental results.

HCl formation via pyrolytic degradation of polyvinyl chloride (PVC): An empirical approach to kinetic modelling

AbstractThe pyrolysis of polyvinyl chloride (PVC) has been described in terms of a relatively simple kinetic model, based on a large number of laboratory tests. The model predictions are in a good agreement with experimental data, regarding hydrochloric acid and non‐condensable combustible gases. Therefore, the proposed model can be used to predict with good approximation the distributions of the above classes of compounds, in the whole range of applied experimental conditions.

Anomalous behavior of molybdenum oxide as a fire retardant for polyvinyl chloride

The widespread application of polyvinyl chloride (PVC) as wire and cable insulation in the communication and electrical industries is due in part to its inherent fire retardant properties, which are improved by the addition of antimony oxide. This addition also increases somewhat the already high rate of smoke formation. Molybdenum trioxide, used either with or instead of Sb 2O 3, has been reported to be a smoke suppressant as well as a flame retardant. This is corroborated by laboratory-scale measurements reported here. However, in a large-scale test under high enthalpy input conditions, MoO 3 appeared to be ineffective in limiting the flame spread. A detailed investigation of the pyrolysis of PVC by thermogravimetric analysis and mass spectroscopy showed that the addition of MoO 3 results in the reduction of the temperature at which HCl is evolved, an increase in the temperature at which the organic pyrolyzate is produced, and a change in compostion of this pyrolyzate from aromatic to aliphatic. The underlying chemical mechanism is explained by the action of MoO 3 as a Lewis acid: 1. 1. The dehydrochlorination of PVC is catalyzed and occurs at a lower temperature; 2. 2. This process yields trans polyenes, either directly or via rapid isomerization of cis polyenes; 3. 3. The trans polyenes, being unable to cyclize and split off benzene, are stable to higher temperatures, at which a different mechanism obtains to give aliphatic products. The ineffectiveness of MoO 3 is ascribed to the difference in flame characteristics between aliphatic and aromatic fuels. The disagreement between laboratory and large-scale tests is attributed to the higher temperature at which the aliphatic pyrolyzate appears, which is reached only under conditions of higher enthalpy input that prevail in the large-scale tests.

Polyvinyl Chloride in Fires

<h3>To the Editor.—</h3> The article "Polyvinyl Chloride Toxicity in Fires" by Dyer and Esch (235:393-397, 1976) contains a number of factual errors and certain misleading inferences. In three places, the combustion of polyvinyl chloride (PVC) is said to produce chlorine and phosgene. In fact, these two materials have never been demonstrated to occur in the pyrolysis or combustion of PVC (<i>Journal of Polymer Science</i>8:1887-1890, 1970;<i>Journal of Applied Polymer Science</i>13:377-391,1969;<i>British Polymer Journal</i>3:186-193, 1971;<i>Journal of Applied Chemistry</i>17:366, 1967). The authors point out, correctly, that hydrochloric acid and carbon monoxide are the main toxic combustion products of PVC but tie these to possible toxic synergy with chlorine or phosgene. It is wrong to raise the specter of toxicants which are not really there. In another instance, vinyl chloride is said to be produced. In work by Boettner et al (<i>Journal of Applied Polymer Science</i>13:377-391, 1969),