Burning Polyvinyl Chloride Research Articles

Evolution of the corrosion layer of Q235 steel in simulated fire‐scene smoke

AbstractThe ability to accurately identify fire patterns is the fundamental requirement for fire investigations. The corrosion layers of steel in fire scenes exhibit three distinct characteristics. First, due to steel's nonflammable nature, steel patterns can be preserved better at the fire site than patterns formed on other combustible materials; second, both the high temperature and the smoke during the fire affect the high‐temperature oxidation process; and third, the corrosion layer of steels inevitably undergoes further evolution after the fire because of the subsequent room‐temperature corrosion. This study focuses on investigating Q235 steel because of its extensive use in construction and vehicles. The pattern evolution processes of high‐temperature oxidation at elevated temperatures in air, polyethylene (PE), and polyvinyl‐chloride (PVC) combustion smoke and the corresponding subsequent corrosion at room temperature were systematically investigated from the perspective of macroscopic and microscopic morphology. The results showed that the smoke atmosphere played an important role in the formation of the corrosion layer of Q235 steel. Compared with samples oxidized in air, samples oxidized in PE combustion smoke exhibited a uniform and dense oxide layer on the surface, which inhibited the corrosion at room temperature further. The PVC combustion smoke accelerated the high‐temperature oxidation of the sample, and its influence on the subsequent room‐temperature oxidation process was closely correlated with the temperature of the high‐temperature oxidation. The results of this study provide important references for understanding the formation of the corrosion layer of Q235 steel for fire investigations.

Interactions of potassium vapor with reactor tubes made of different materials and their impacts on particulate matter emission during pulverized biomass combustion

During the combustion of biomass in drop-tube furnace (DTF) systems, the released alkali metal (e.g., potassium, K) inevitably reacts with reactor tube at high temperatures, affecting the experimental results on the emission of particulate matter with aerodynamic diameters of <10 μm (PM10). This study reports the interactions between K vapor and tube reactors made of silicon carbide, corundum, and mullite and their impacts on PM10 emission. Demineralized wood samples loaded with potassium chloride (KCl) or ion-exchanged K respectively were combusted in a DTF at 1300 °C under air or oxy-fuel atmosphere. Another series of experiments was conducted to collect and analyze the PM10 from the combustion of KCl-loaded wood, K-exchanged wood, and two typical biomass samples (cotton stalk and wheat straw) in the three reactor tubes under air atmosphere. Experimental results show that 4.1‒72.5% of K is retained in the three tubes when burning the KCl-loaded wood in air, and the combustion in oxy-fuel atmosphere slightly increases the K retention. For K-exchanged wood combustion in air, only 3.7‒23.6% of K is released from the reactor tubes. In all conditions, the reactivity of the reactor tubes with K vapor follows a sequence of mullite > corundum > silicon carbide. The retained K is unstable, 49.0‒64.8% of which can be re-released during polyvinyl chloride combustion. In addition, the results demonstrate that, compared with silicon carbide tube, the use of corundum and mullite tubes leads to a 16.2‒54.3% decrease in PM1 yields and a significant drop in fine mode peaks in PM10 during the combustion of biomass samples in air, while the PM1–10 yields and the coarse mode peaks remain largely unchanged. These are attributed to the enhanced retentions of alkali metals in corundum and mullite tubes, which reduce the yields of Na, K, and Cl in PM10, but has negligible effect on those of refractory elements such as Mg and Ca.

Quantitative Hydrogen Chloride Detection in Combustion Environments Using Tunable Diode Laser Absorption Spectroscopy with Comprehensive Investigation of Hot Water Interference.

Hydrogen chloride (HCl) monitoring during combustion/gasification of biomass fuels and municipal solid waste, such as polyvinyl chloride (PVC) and food residues, is demanded to avoid the adverse effect of HCl to furnace operation and to improve the quality of the gas products. Infrared tunable diode laser absorption spectroscopy (IR-TDLAS) is a feasible nonintrusive in-situ method for HCl measurements in harsh environments. In the present work, the measurement was performed using the R(3) line of the ν2 vibrational band of HCl at 5739.25 cm–1 (1742.4 nm). Water vapor is ubiquitous in combustion/gasification environments, and its spectral interference is one of the most common challenges for IR-TDLAS. Spectral analysis based on the current well-known databases was found to be insufficient to achieve an accurate measurement. The lack of accurate temperature-dependent water spectra can introduce thousands parts per million (ppm) HCl overestimation. For the first time, accurate spectroscopic data of temperature-dependent water spectra near 5739.3 cm–1 were obtained based on a systematic experimental investigation of the hot water lines in a well-controlled, hot flue gas with a temperature varying from 1100 to 1950 K. With the accurate knowledge of hot water interference, the HCl TDLAS system can achieve a detection limit of about 100 ppm⋅m at around 1500 K, and simultaneously the gas temperature can be derived. The technique was applied to measure the temporally resolved HCl release and local temperature over burning PVC particles in hot flue gas at 1790 K.

The volatilization of heavy metals during combustion of polyvinyl chloride after hydrothermal carbonization

This paper experimentally investigated the volatilization characteristic of five heavy metals (cadmium, chromium, nickel, lead and zinc) during combustion of hydrochars of polyvinyl chloride with hydrothermal carbonization pretreatment. The differences of volatilization rate of cadmium and lead between polyvinyl chloride and hydrochars were within 5%, indicating that hydrothermal carbonization had no significant effects on their volatilization behavior. Higher hydrothermal carbonization temperature and lower combustion temperature resulted in lower volatilization rate of zinc. For chromium and nickel, although their volatilization rates were lowered, the absolute volatilization rates increased remarkably because of the increase of original concentrations. Nevertheless, the total emissions of heavy metals studied reduced. Hydrothermal carbonization performed at 230 °C showed the most significant absolute volatilization rates reductions ranged from 79.2% to 86.8% depending on combustion temperature. The highest concentrations of chromium and nickel in bottom ash reached up to 20.1 g/kg and 7.9 g/kg, respectively.

Thermal behavior and kinetic analysis of co-combustion of wheat straw and polyvinyl chloride under different oxygen concentrations through thermogravimetry

Co-combustion characteristics of wheat straw with polyvinyl chloride under different oxygen concentration atmospheres were investigated using a thermogravimetric analyzer. Experimental samples included wheat straw, polyvinyl chloride, and their blends. The results showed that when the wheat straw was blended with polyvinyl chloride, there was an inhibition for devolatilization in the volatile combustion stage. However, during the char combustion stage, a promotion was observed. As the oxygen concentration increased from 10% to 40%, the ignition temperatures, burnout temperatures, and maximum reaction rate temperatures of all samples decreased, and the combustion characteristic factors ( SN) increased. The combustion of wheat straw was significantly affected by oxygen concentration, whereas the polyvinyl chloride and blends were affected relatively slightly. Especially, as the oxygen concentration increased from 30% to 40%, the combustion of polyvinyl chloride and blends improve slightly. The reason for this behavior is attributed to the diffusion effects of the oxygen and the microstructure changes of the samples. In addition, the activation energies of the co-combustion process under the four atmospheres, for all samples, were calculated by Flynn–Wall–Ozawa method. The kinetic results show that the diffusion effect of the oxygen influenced the apparent activation energies of combustion reaction and the compensation effect of activation energies exists.

Releases of Fire-Derived Contaminants from Polymer Pipes Made of Polyvinyl Chloride.

In order to assess the human exposure risks from the release of contaminants from water pipes made of polyvinyl chloride (PVC), experiments were carried out by subjecting the PVC pipe material to burning and leaching conditions followed by analysis of the emission and leachate samples. The emissions of burning pipes were analyzed by both infrared spectrometry and gas chromatography-mass spectrometry (GC-MS). The emission test results indicate the presence of chlorinated components including chlorine dioxide, methyl chloride, methylene chloride, allyl chloride, vinyl chloride, ethyl chloride, 1-chlorobutane, tetrachloroethylene, chlorobenzene, and hydrogen chloride were detected in the emissions of burning PVC pipes. Furthermore, the concentrations of benzene, 1,3-butadiene, methyl methacrylate, carbon monoxide, acrolein, and formaldehyde were found at levels capable of affecting human health adversely. The analysis of PVC pipe leachates using GC-MS shows that there are 40–60 tentatively identified compounds, mostly long-chain hydrocarbons such as tetradecane, hexadecane, octadecane, and docosane, were released when the burned PVC materials were soaked in deionized water for one week. Quantitative analysis shows that 2-butoxyethanol, 2-ethyl-1-hexanol, and diethyl phthalate were found in the burned PVC polymer at the average levels of 2.7, 14.0, and 3.1 micrograms per gram (μg/g) of pipe material. This study has significant implications for understanding the benzene contamination of drinking water in the aftermath of wildfires that burned polymer pipes in California.

Scientific experiment focused at pigment degradation by polyvinyl chloride combustion in Science education

The Environmental education navigates students towards environmentally friendly life style and securing a quality of life. The implementation of cross-section topics, including the Environmental education, into science classes, is possible through a variety of techniques. One of the least used methods is a real school experiment. The following paper presents the experiment, by which we simulate the combustion of PVC and observe the impact of combustion products on plants via UV-Vis spectrophotometry optical method. This method is suitable for qualification and analysis of vegetable pigments, i.e. chlorophylls, carotenoids, and anthocyanins. The experiment is integrated into the Techniques and Didactics of School Chemistry Experiments as a part of master degree course, which prepares students for the Chemistry teaching profession. The introduced experiment enables pedagogues to integrate the environmental education into teaching process and develop mathematical and science literacy of students in the Chemistry education.

On the Environmental Hazard of Burning Organic Waste in the Presence of Chlorine Compounds

The problems of formation of toxic chlororganic compounds during waste incineration in the presence of organic and inorganic chlorine compounds are considered. It is shown that the radical mechanism of pyrolysis leads to different products with different composition of the initial substances. It was found that the greatest environmental danger is the joint burning of chlororganic and aromatic compounds. When burning polyvinyl chloride together with other polymeric materials, especially the aromatic structure, not only light chlororganic compounds are formed, but also highly toxic carbonyl chloride and chlor-furan. The formation of the above compounds represents a potential danger of further chemical conversions and the production of chlorinated dioxin compounds. It is proposed to prevent the formation of highly toxic compounds from the burning of polyvinyl chloride, its mandatory separation from the solid municipal waste stream and its separate processing by flameless methods.

The effects of poly(amide-imide) coating on the thermal, combustion and mechanical properties of polyvinyl chloride ZnO nanocomposites

The surface of new polyvinyl chloride (PVC)/ZnO nanocomposite films was coated using semi-aromatic synthesized poly(amide-imide) (PAI) by dip-coating process. ZnO nanoparticles were organo-modified with imide functionalized polyethyleneimine (PEI) and were used for preparation of PVC nanocomposite films by solution casting method. The effect of PAI coating along with PEI surface modified ZnO nanoparticles (PSZN) on the morphology, thermal stability, combustion and mechanical properties of PVC were investigated. The uniform dispersion of ZnO nanoparticles and PAI coating manner on surface of the PVC films were confirmed by ATR-FTIR spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray and elemental mapping. From thermal gravimetry analysis (TGA) results, the 10 mass% loss temperature (T10) increased from 229 °C to 244 °C in PVC-coated with PAI containing 2 mass% of PSZN and also char residue of PVC increase from 10.5 to 28.9% in PVC-coated contaning 5 mass% of PSZN. According to microscale combustion calorimetry (MCC) and tensile test results, the peak of heat release rate decreased from 129.8 W/g to 81.2 W/g and the tensile strength increased from 28.7 to 43.6 MPa for PVC-coated containing 5 mass% of PSZN compared to the neat PVC.

Corrosion behavior assessment of tin-lead and lead free solders exposed to fire smoke generated by burning polyvinyl chloride

The corrosion characteristics of tin-lead and three lead free solders (Sn-0.7Cu, Sn-3.0Ag and Sn-3.0Ag-0.5Cu) exposed to fire smoke generated from polyvinyl chloride (PVC) were comparatively investigated through weight loss method and surface characterization techniques. Results show that the corrosion rates of each of four examined solders rise with the increase of smoke concentrations over the concentration range from 20 g/m3 to 140 g/m3. Sn-37Pb solder exhibits the optimal corrosion resistance, while lead free Sn-3.0Ag-0.5Cu solder has much poorer corrosion resistance in comparison with the former, even with the Sn-0.7Cu and Sn-3.0Ag alloys. As indicated by SEM and XRD, the corrosion resistance of these lead free solders may be related to their microstructure. When the alloys involve more intermetallic compounds, the more larger cathode areas are presented, the weaker the corrosion resistance seems to be. Further, XRD and Raman spectrum reveal that SnO and PbCl2 are the main corrosion products of Sn-37Pb solder, while those of lead free solders primarily consist of Sn21Cl16(OH)14O6 and SnO. Accordingly, the corrosion mechanisms are further analyzed.

Mechanism of Formation of Chlorinated Pyrene during Combustion of Polyvinyl Chloride.

Chlorinated polycyclic aromatic hydrocarbons (ClPAHs) are an emerging class of environmental contaminants, but the sources of these chemicals in the environment are not well-known. In this study, we developed a kinetic model describing the chlorination of PAHs to elucidate the mechanism of formation of ClPAHs during the combustion of organic waste containing chlorinated compounds and/or chlorine in an incinerator. Pyrene (Pyr) and polyvinyl chloride (PVC) were selected as a model PAH and a model organic substrate, respectively. All combustion experiments were carried out using a model furnace operated under similar experimental conditions. Combustion of PVC in the model furnace produced 1-ClPyr, 1,3-Cl2Pyr, 1,6-Cl2Pyr, 1,8-Cl2Pyr, 1,3,6-Cl3Pyr, and 1,3,6,8-Cl4Pyr. The developed model supported the experimental data on the sequential chlorination of pyrene. The rate constants for the formation of mono- to trichlorinated pyrenes were over 30 times of those for the formation of tetra- and penta-chlorinated pyrenes. A qualitative analysis of the formation of highly chlorinated pyrenes based on the comparison of theoretical and empirical isotopic patterns of the mass spectrum revealed that penta- and hexa-chlorinated pyrenes, whose analytical standards were not available, were also produced by the combustion of PVC.

Corrosion behavior of Sn‐3.0Ag‐0.5Cu solder under different fire smoke atmospheres generated by burning polyvinyl chloride and polyethylene

The corrosion characteristics of Sn‐3.0Ag‐0.5Cu solder under polyvinyl chloride (PVC) and polyethylene (PE) fire smoke atmospheres were investigated by weight loss method and surface characterization techniques. The corrosion kinetics results of 15‐day tests show that the mass loss of Sn‐3.0Ag‐0.5Cu solder in PE smoke is much lower than that in PVC smoke. The former shows no significant variation during the test. In contrast, the latter increases rapidly first and then presents a slow exponential increase. Microstructure analysis indicates that no obvious corrosion product appeared in PE smoke. Nevertheless, the corrosion products in PVC smoke grow larger first and then become smaller and denser. The possible growth process of corrosion products is that grain growth dominates the formation of the corrosion products at the initial stage and then the nucleation process is predominant. Furthermore, the corrosion mechanisms of Sn‐3.0Ag‐0.5Cu solder in the different fire smoke are also analyzed. Stannous oxide and stannic oxide are regarded as the corrosion products under both PE and PVC smoke atmospheres, while Sn21Cl16(OH)14O6 is only observed under PVC smoke atmosphere.

Dioxins and polyvinylchloride in combustion and fires.

This review on polyvinylchloride (PVC) and dioxins collects, collates, and compares data from selected sources on the formation of polychlorinated dibenzofurans (PCDFs) and dibenzo-p-dioxins (PCDDs), or in brief dioxins, in combustion and fires. In professional spheres, the incineration of PVC as part of municipal solid waste is seldom seen as a problem, since deep flue gas cleaning is required anyhow. Conversely, with its high content of chlorine, PVC is frequently branded as a major chlorine donor and spitefully leads to substantial formation of dioxins during poorly controlled or uncontrolled combustion and open fires. Numerous still ill-documented and diverse factors of influence may affect the formation of dioxins during combustion: on the one hand PVC-compounds represent an array of materials with widely different formulations; on the other hand these may all be exposed to fires of different nature and consequences. Hence, attention should be paid to PVC with respect to the ignition and development of fires, as well as attenuating the emission of objectionable compounds, such as carbon monoxide, hydrogen chloride, polycyclic aromatic hydrocarbons, and dioxins. This review summarises available dioxin emissions data, gathers experimental and simulation studies of fires and combustion tests involving PVC, and identifies and analyses the effects of several local factors of influence, affecting the formation of dioxins during PVC combustion.

Beyond the fire: smoke inhalational injury as a respiratory concern

In fire events, smoke inhalation is the leading cause of death in survivors of the primary fire mortality. Direct upper airway thermal injury is only one of the contributing mechanisms. Others may be related to the nature of the combusted (or incomplete combusted) materials in the scene; eg.; aldehydes, sulphur oxides and nitrogen as a cotton combustion products, while burning polyvinylchloride (PVC's) releases carbon monoxide (CO) and hydrochloric acid, among more than 75 potentially toxic compounds including cyanide. Hot carbonated gaseous materials and soot may lead to supraglottic, glottic, or infraglottic airway obstruction however; significant hypoxemia is not the typical sign in acute cases without aspiration or parenchymal lung injuries. Injury may not manifest until after 48 hours.

Thermogravimetric characteristics and combustion emissions of rubbers and polyvinyl chloride in N2/O2 and CO2/O2 atmospheres

The thermogravimetric characteristics of tire rubber (TR), rubber mattress (RM) and polyvinyl chloride (PVC), representing the rubber and plastic materials of municipal solid waste (MSW) were compared under 80N2/20O2 and 80CO2/20O2 atmospheres. Replacement of N2 by CO2 reduced the weight loss rate of most peaks below 600°C, postponed the location of the peaks above 600°C, and resulted in less complete burnout, which indicated the combustion in CO2/O2 atmosphere decreased the reactivity of the samples. The emissions of TR, RM and PVC combustion in a tube reactor were analyzed by a flue gas analyzer. The concentrations of CO, H2, SO2 and NOx all increased initially and decreased afterwards along with the heating time. During 800–1000°C, NOx and SO2 emissions of all samples increased by the temperature, and decreased by the replacement of N2 by CO2. In both atmospheres, the subsequence of the NOx emission was TR>RM>PVC, and the subsequence of the SO2 emission was TR>PVC>RM. The effects of temperature and atmosphere on the CO and H2 emissions of two rubbers were different from those of PVC.

Experimental study of detritiation system catalyst poisoning

The catalyst of the ITER Vent Detritiation System (VDS) has to oxidise the tritiated gases: the resulting tritiated water is trapped in order to provide the tritium confinement function of the VDS. An experimental study has been carried out in order to determine the VDS catalyst ability to operate when exposed to the products of combustion released during a fire. In our tests the VDS catalytic recombiner has been tested in the presence of fumes generated by the combustion of selected materials (polyvinyl chloride, methyl methacrylate, vacuum pump oil and polytetrafluoroethylene). These materials have been burnt in an oven at 200 °C: the arising combustion fumes have been sent into a catalytic bed where a Pt 0.5% on alumina catalyst operated the conversion of the tritiated gases into tritiated water at 400 °C with a spatial velocity of 6000 h −1. The catalyst efficiency has been assessed by adding tritium as a tracer to the combustion fumes entering the catalytic recombiner and measuring the activity of the tritiated water collected after this reactor. The studied catalyst has been mainly affected by the fumes coming from the combustion of polyvinyl chloride: the measured catalyst efficiency has been 86.7%. Especially, in this case the presence of chlorides would have impaired the detritiation process by poisoning the catalyst. The combustion tests with methyl methacrylate and vacuum pump oil with polytetrafluoroethylene have shown slither reduced catalyst efficiencies of 91.1 and 93.5, respectively.

Experimental Study of Suppressing PVC Fire with Water Mist using a Cone Calorimeter

Effect of water mist on the small-scale solid fuel PVC (poly vinyl chloride) fire in a confined space has been studied experimentally using a cone calorimeter. In this study, the combustion characteristics of PVC, and the interaction between the water mists and the diffusion flame in a confined space with proper ventilation control are studied under various conditions in the cone calorimeter. The water mist is generated by a single pressure nozzle and the diffusion flame is produced from PVC samples, respectively. The Laser Doppler Velocimetry/Adaptive Phase Doppler Velocimetry LDV/APV system is employed to determine the water mist characteristics. The results of the test showed that the combustion of PVC is a two-step process, the water mist suppress the diffusion flame in a confined space via oxygen displacement, heat extraction, and heat radiant attenuation. Heat extraction (flame cooling and fuel surface cooling) plays a dominant role by suppressing the PVC fire when the water mists of enough volume flux are applied to the diffusion flame in a confined space. The higher the operational pressure, the easier the suppression.

Photolysis of polycyclic aromatic hydrocarbons associated with fly ash particles under simulated sunlight irradiation

Fly ash particle-associated polycyclic aromatic hydrocarbons (PAHs) were produced by combustion of polyvinyl chloride (PVC), wood, high-density polyethylene (HDPE), and polystyrene in a stove. Fly ash particles were deposited on the glass slides (76 mm × 26 mm) placed in the exposure chamber. The concentration of 16 PAHs ranged from 10.1 pg/dm 2 fly ash for acenaphthene to 2348.7 pg/dm 2 fly ash for fluoranthene. Medium to large molecular weight PAH concentrations were much higher compared to low molecular weight PAHs on fly ash. Photolysis of PAHs associated with fly ash particles deposited on glass slides was investigated under simulated sunlight irradiation for about 550 h. Generally, the photolysis rates of the 16 PAHs follow first-order kinetics. Under simulated sunlight containing UV-B, the photolysis of PAHs includes two phases: fast (0–50 h) and slow phase (50–550 h). The photolysis rate constants of PAHs in the initial fast phase were far greater than those in the slow phase. When UV-B was removed from the simulated sunlight irradiation, the photolysis rate constants of PAHs were significantly lower compared to those observed in the fast phase with UV-B exposure, suggesting UV-B radiation could accelerate photolysis of PAHs adsorbed on the fly ash particles. In addition, partial least squares (PLS) analysis models were applied to explain the molecular structural characteristics that affect the PAH photolysis rates. The results suggested that the photolysis rate constants of PAHs decrease with the increasing of molecular weight ( M w), the energy of the lowest unoccupied molecular orbital ( E LUMO), E LUMO + E HOMO, and the standard heat of formation (Δ H f).

Polychlorinated naphthalenes and other chlorinated tricyclic aromatic hydrocarbons emitted from combustion of polyvinylchloride

Chloronaphthalenes (CNs) and phenanthrenes or/and anthracenes (CP/CAs) were detected in the emissions of polyvinylchloride (PVC) combustion at 900 °C. The presence of metallic iron, copper, or aluminum increased the formation of highly chlorinated CNs (tri- to octachloro-homologues) in the PVC combustion process. Total levels of CNs and CP/CAs were 40–48 and 76–116 mg/kg PVC, respectively, in the emissions from combustion of PVC with metals. Monochloronaphthalenes, dichloronaphtahlenes, monochlorophenanthrenes, and monochloroanthracenes were the predominant homologues. The other CN homologues were minor combustion byproducts. Detection of CNs in the PVC combustion emissions suggests that CN formation from solid waste incineration is a source of CNs in the environment.

Semivolatile and volatile compounds from the pyrolysis and combustion of polyvinyl chloride

Emissions evolved from the pyrolysis and combustion of polyvinyl chloride (PVC) were studied at four different temperatures (500, 700, 850 and 1000 °C) in a horizontal laboratory tubular quartz reactor in order to analyse the influence of both temperature and reaction atmosphere on the final products from thermal and oxidative reactions. It was observed that the CO 2/CO ratio increased with temperature. Methane was the only light hydrocarbon whose yield increased with temperature up to 1000 °C. Benzene was rather stable at high temperatures, but in general, combustion at temperatures above 500 °C was enough to destroy light hydrocarbons. Semivolatile hydrocarbons were collected in XAD-2 resin and more than 160 compounds were detected. Trends on polyaromatic hydrocarbon (PAH) yields showed that most had a maximum at 850 °C in pyrolysis, but naphthalene at 700 °C. Formation of chlorinated aromatics was detected. A detailed analysis of all isomers of chlorobenzenes and chlorophenols was performed. Both of them reached higher total yields in combustion runs, the first ones having a maximum at 700 °C and the latter at 500 °C. Pyrolysis and combustion runs at 850 °C were conducted to study the formation of polychlorodibenzo- p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs). There was more than 20-fold increase in total yields from pyrolysis to combustion, and PCDF yields represented in each case about 10 times PCDD yields.