PVC Waste Research Articles

Pyrolysis characteristics and non-isothermal torrefaction kinetics of industrial solid wastes

Due to low degradability and high risks of toxic emissions, thermochemical conversions of plastics and textile among industrial solid wastes (ISWs) into biofuels are more favorable compared with common waste treatment options such as landfilling and burning. In this study, pyrolysis and non-isothermal torrefaction characteristics of two representative ISWs including PVC and oil cloth wastes are investigated using a thermogravimetric analyzer to understand their thermodegradation behaviors. The results show that the pyrolysis of the ISWs are characterized by three different decomposition stages. A high heating rate is more energy efficient for non-isothermal torrefaction of oil cloth waste, whereas PVC waste is more suitable for non-isothermal torrefaction at a low heating rate. An independent parallel reaction (IPR) model is developed to predict the non-isothermal torrefaction dynamics of the wastes. It is found that the thermodegradation can be well predicted with an assumption of two components. Furthermore, the extracted kinetic data show that the kinetic parameters of an ISW component are much higher than those of common woody and algal biomass.

PVC concrete composites: comparative study with other polymer concrete in terms of mechanical, thermal and electrical properties

Recycling PVC wastes with conventional chemical recycling methods such as pyrolysis, gasification is not feasible due to the carbon dioxide and dioxin emmissions generated with these methods. PVC wastes can be disposed using in ready-mixed concrete which is the most commonly used building material. In this study, effects of waste PVC instead of fine aggregate and the effects of waste PVC on the concrete properties were analyzed using 0%, 30%, 35%, 40% and 45% (w/w) in the experiments. Effects of waste PVC in concrete were compared with the other waste polymer concrete in terms of mechanical, thermal and electrical properties. All waste polymers have reduced the mechanical strength of concrete as expected. Improvement rates for the splitting tensile strength for 28 days are found to be 54.46%, 48.52% and 6.93% for PP, PET and rubberized concrete, respectively, in comparison with reference concrete. For thermal conductivity, improvement rates for 40% PC, 40% PP and 40% PVC concrete are found to be 52.56%, 44.87% and 42.31%, respectively. For electrical resistivity, the highest improvement rate was determined as 136.03%, 132.38% and 105.92% for PC, PVC and rubberized concrete, respectively.

Waste-Based Construction Materials

The article is devoted to the research into the utilization of large volume industrial wastes to produce mineral-polymer composite construction materials. To produce the composites, polyvinyl chloride wastes have been suggested as binding thermoplastic matrix and ash-and-slag wastes, which are the by-product of coal combustion at TPP of Irkutsk Oblast, as mineral filler. Since the problem of accumulation and storage, such as large volumes of power generation industry wastes is becoming more and more serious, the recycling of these wastes with the production of useful products is the vital task. Plants that manufacture products from PVC also produce plastic wastes in the form of rejected and substandard raw material, which can be recycled. At the same time, the problem of production available construction materials for the Baikal region from the local cheap raw material is solved. The team of Irkutsk National Research Technical University has conducted a number of the industrial trials on the production of mineral-polymer composites by the method of extrusion. As a result, the principal opportunity of co-utilization of PVC wastes and ash-and-slag materials during the production of composite construction materials has been testified. Local construction companies can use the produced materials.

Some properties of concrete with plastic aggregate derived from shredded PVC sheets

This paper describes experimental tests on concrete made of coarse aggregate or fine aggregate partially replaced with plastic waste derived from PVC waste sheets. The main goal behind this experiment is the inspection of important properties of concrete affected by the plastic waste addition, for the purpose of consuming the waste and production of an eco-friendly concrete. Results indicate that there is a chance to replace fine or coarse aggregate with PVC aggregate not more than 30% for the production of concrete with acceptable properties. At this plastic content there is a margin loss of workability, absorption, and different strengths. Compressive and splitting tensile strengths loss was found not more than 8%. Elastic modulus of concrete is highly affected by the existence of PVC aggregate, especially when coarse aggregate is replaced. Abrasion resistance of concrete can be increased well as PVC aggregate is used instead of the natural one especially coarse aggregate.

Degradation of PVC waste into a flexible polymer by chemical modification using DINP moieties.

In consideration of the toxicity and high migration capacity of plasticizers, the possibility to obtain flexible PVC via chemical modification of PVC was investigated for feedstock recycling. In this work, some Cl atoms of PVC were substituted with fragments of the common plasticizer DINP (diisononyl phthalate) in the presence of K2CO3 (potassium carbonate) or DIEA (N,N-diisopropylethylamine), and the simultaneous elimination of PVC was suppressed. 1H NMR (1H nuclear magnetic resonance spectroscopy) and 1H–1H COSY (1H–1H correlation spectroscopy) were used to evaluate the substitution while a novel method of calculating the substitution and elimination ratios was developed using a combination of 1H NMR and elemental analysis. A maximum substitution rate of 35.7% was achieved using thiophenol as a nucleophile in the presence of DIEA, while the corresponding elimination of HCl was just 4.4%. In addition, the thermal stability of the modified PVCs was very close to that of pure PVC, which suggested that the main characteristics of PVC were preserved. Moreover, the Tg values of all the modified PVCs were less than that of PVC, which means it is feasible to improve the plasticity of PVC via substituting some Cl on PVC with DINP moieties. Therefore, an alternative approach for feedstock recycling of PVC by chemical modification was developed in this work.

Controlled Dehydrochlorination of Poly(vinyl chloride) for Fabrication of Membranes with Polyacetylene-Like Structure: XPS Analysis and Ion Exchange Membrane Discussion

Poly(vinyl chloride) (PVC) can be dehydrochlorinated by strong bases, e.g. tert-butoxide and hydroxide, to attain polyacetylene-like highly conjugated polymer chains. Dehydrochlorinated PVC (DHPVC) can be further functionalized by additional reactions to obtain ion exchange membranes, battery membranes, semiconductors, etc. However DHPVC resin is not available for membrane casting because of its low solubility. Therefore dehydrochlorination was performed directly on PVC membranes in this research. The extent of dehydrochlorination and the length of conjugation were controlled by adjusting conditions such as base/PVC ratio and solvent type. X-ray photoelectron spectrometry and elemental analysis were used to detect Cl, C, O, and H contents of the products. A calculation method that uses parameters of atomic approximations, was proposed to mathematically express trends of “degrees of dechlorination, dehydrochlorination, unsaturation, and substitution” with respect to the amount of base used. Up to 64.5% unsaturation and 96.6% dechlorination of PVC membranes were achieved. In addition, theoretical ion exchange capacity (IECtheo) was defined with a suggestion that charged functional groups can be attached to the polymer backbone by double bonds, allowing ion exchange membranes to be manufactured. By tailoring the degree of unsaturation in dehydrochlorinated species, theoretically up to 18 meq/g of IEC would be reached if all double bonds would be functionalized. Scanning electron microscopy analysis showed that tert-butoxide products had a porous structure. FTIR and UV-Visible spectroscopy results verified the formation of long polyene sequences. Dehydrochlorination may be a legitimate method for recycling PVC waste into functional membrane materials.

A novel treatment method of PVC-medical waste by near-critical methanol: Dechlorination and additives recovery

Before PVC-medical waste is subjected to a waste-to-energy recovery process, the dechlorination and the recovery of additives such as plasticizer, stabilizer, and lubricant are quite important and attractive. In this work, a novel process was developed for the dechlorination and the recovery of additives from PVC-medical waste such as tube for transfusion (TFT) and sample collector for urine (SCFU) by using near-critical methanol (NCM). Reaction temperature, solid-to-liquid ratio, and reaction time have significant effect on the dechlorination of TFT and SCFU in NCM. The order of dechlorination efficiency of the samples at the same reaction conditions is as follows: TFT > Pure PVC > SCFU. When reaction temperature was controlled at 250 °C (solid-to-liquid ratio of 1:10 g/mL, reaction time of 60 min), the dechlorination efficiency reached 90%. Plasticizer such as dibutyl phthalate (DBP), dioctyl phthalate (DOP), and dimethyl phthalate (DMP) could be efficiently extracted and recovered from TFT at 250 °C by the NCM process. The recovery efficiency of DBP, DOP, and DMP decreased significantly with increasing temperature due to the further decomposition and other secondary reactions. High level of hexadecanoic acid methyl ester and octadecanoic acid methyl ester can be obtained from SCFU at 250 °C by the NCM process because of the esterification between methanol and hexadecanoic acid/octadecanoic acid, which are the important stabilizers and lubricants generally used in rigid PVC. It is noteworthy that methanol can be circulated and reused in the NCM process. This result showed that the NCM process was beneficial for both the dechlorination and the additives recovery from PVC-medical waste, and had a widespread application prospect for the waste management of PVC wastes.

Replacement of Sand By PVC Pipe Waste in Pavement Blocks

In the present research an attempt has been made to replace some part of fine aggregate (sand) by an industrial waste, the industrial waste under investigation is produced when the PVC pipes are cut into the desired sizes, it is a very thin flaky substance having a specific gravity of 1.5.This material is very voluminous in nature, so it reduces the workability of concrete if used in large percentage. So this material cannot be used in very large quantities but it can successfully replace sand up to 20 percent when used in pavement blocks. Experimentation was done at a water-cement ratio ranging from 0.43-0.35.Compressive strength of the concrete has been evaluated at 7 days, 14 days 21 days and 28 days. Results of the investigation indicate that compressive strength of the concrete decreases as the percentage of PVC waste material increases.7 day strength of the concrete has varied from 35.55 MPa to 70.01 MPa and 28 day strength has varied from 56.7 MPa to 76 MPa. Water absorption was well within the limits and varied from 4.67% to 7.26% by mass. The results revealed that this waste material can satisfactorily replace sand in small amount also it is a great way to dispose of the waste and hence is a step forward in the quest for a greener concrete.

Thermal decomposition mechanisms of poly(vinyl chloride): A computational study

The studies on the pyrolysis mechanisms of waste PVC contribute to development and application of pyrolysis technology for mixed waste plastics. In the article, the thermal decomposition mechanisms of model compound of poly(vinyl chloride) (PVC) have been investigated by employing density functional theory methods at M06-2X/6–31++G(d,p) level in order to illuminate the elimination of HCl and the formation of hydrocarbons. Various possible pyrolysis paths for the formation of main products were proposed, and the thermodynamic and kinetic parameters in every path were calculated. The calculation results show that the HCl elimination can occur through the concerted reaction and the energy barrier of HCl elimination changes from 167.4 to 243.3 kJ/mol; allyl group can obviously reduce the activation energy of HCl elimination, and the branched-chain can lower the energy barrier of HCl elimination at the carbon sites near the branch chain; a free radical is more easily converted into aromatic compound through a series of isomerizations, cyclization and dehydrogenation; the conjugated polyene could be decomposed in parallel reaction channels: one is the evolution of aromatics, another is the formation of small molecule products. The above analysis is consistent with previous experimental results and analysis.

Recycling of plastic waste materials in the composition of ecological mortars

Today, the wish to maintain and improve living conditions worldwide has led to a particular focus on ecology issues in all areas of activity, including construction. The research demonstrates that it is possible to solve major problems in the management of plastic waste materials by recycling, and to obtain new building materials. In this study, the optimal recipes for the manufacture of ecological mortars by PVC waste recycling were established. Mortars containing PVC waste have the advantage that their production is less polluting, as it does not involve high energy consumption. The study presented in this paper is finalized with the development of new building materials.

A new approach to transforming PVC waste into energy via combined hydrothermal carbonization and fast pyrolysis

Abstract The hydrothermal carbonization (HTC) of poly (vinyl chloride) (PVC) was studied. The results showed that the HTC temperature could significantly accelerate the HTC dechlorination of PVC at a relative mild condition. The carbon content of solid product (hydrochar) treated at 260 °C was 82%, which was similar to sub-bituminous coal. According to the FTIR and 13C NMR spectrum, elimination, substitution, aromatization and polymerization occurred during the HTC. With the temperature increasing, the degree of aromatization was deeper. The SEM analysis showed the surface morphology of hydrochar much differed from that of raw sample. Hydrochar treated at 200 °C had pore structure, while the structure of hydrochar treated at 230 and 260 °C was partially destructed. The Py-GC/MS analysis showed that evolved products of hydrochars treated at 200 and 230 °C was HCl, alicyclic & aliphatic hydrocarbons, benzene, toluene, naphthalene, diphenyl and phenanthrene. While evolved products of hydrochars treated at 260 °C contains large amount of alicyclic & aliphatic hydrocarbons. Py-GC/MS analysis also showed as the pyrolysis temperature increased from 500 to 900 °C, the content of aromatic hydrocarbons increased. The relative peak area of alicyclic & aliphatic hydrocarbons was largest at 600 °C.

Characteristics of co-hydrothermal carbonization on polyvinyl chloride wastes with bamboo

The PVC waste and bamboo were treated by co-hydrothermal carbonization (co-HTC) at three different temperatures. The inorganic-Cl could be removed from the carbon rich solid products (hydrochar) in the form of HCl via hydrolysis, elimination, substitution and aromatization. Due to the high carbon content, the hydrochar could be applied as premium fuel. Bamboo had a synergistic effect on dechlorination with PVC in the HTC process. The bamboo could accelerate the HTC dechlorination of PVC at 200°C because it strengthened the substitution of Cl with OH. While at 230 and 260°C, the existence of bamboo hindered the dechlorination of PVC in HTC. Thermogravimetric analysis showed the combustion performance of hydrochar was better than the raw samples at 200°C. Owing to the low chlorine content, low ignition temperature and the superior combustion performance, the M-260 can be adopted as alternative fuels for coal.

C, H, Cl, and In Element Cycle in Wastes: Vacuum Pyrolysis of PVC Plastic To Recover Indium in LCD Panels and Prepare Carbon Coating

Resource recycling of millions of solid wastes is a world’s problems. Because element is the basic unit of all wastes, the essence of wastes recycling is to realize cycle of elements in wastes. In this paper, a new concept of element cycle in wastes is proposed. Under guidance of element cycle, various wastes have common connection point. The concept is clarified by a case of C, H, Cl and In element cycle from waste PVC plastic and LCD panels. In this paper, a vacuum pyrolysis of waste PVC was proposed to recycle indium in LCD and synchronously prepare carbon coating. Cl in PVC combined with In in LCD was mainly regenerated in the form of InCl3. Meantime, C and H in PVC were reused to prepare carbon coating and energy products, such as pyrolysis oil and gas. The recycling system means to change two kinds of wastes into resources by their own element characteristics. Under optimized conditions, recovery rate of indium exceeded 98 %. Meantime, with increasing temperature, microstructure of carbon coating is...

Desain Lean Production Dengan Aspek Sustainability dan Logika Fuzzy pada Value Stream Analysis Tools

This article measures and identifies waste and designs alternatives to reduce waste in one SME in Yogyakarta, thus increasing efficiency. The lean manufacturing approach uses Value Stream Mapping that applies sustainability concepts. The research methodology used in this research is case study strategy. Based on the analysis of Current State Mapping there are many activities that are not important and should be reduced. The sustainability aspect in Gendhis Bag covers the environmental aspect with a 10% limit on skin waste and 15% for PVC waste. Energy consumption for production is 750 watts and labor cost is Rp 32,800 per unit. Safety operators have a very small accident rate, while the largest Physical Load Index score is in the cutting department. Future state VSM shows that NNVA and NVA time can be significantly reduced and lead time can be reduced, so production can increase 12 units per day.

7-4-1 廃PVC・廃ガラス同時処理によるセメント原燃料併産プロセスの開発(7-4 リサイクル,Session 7 環境対策・リサイクル,研究発表)

7-4-1 廃PVC・廃ガラス同時処理によるセメント原燃料併産プロセスの開発(7-4 リサイクル,Session 7 環境対策・リサイクル,研究発表)

7-10.廃塩ビリサイクル-廃ガラスによる塩素の中和および塩ビ中の炭酸カルシウムの影響((3)環境対策,Session 7 環境対策・リサイクル)

7-10.廃塩ビリサイクル-廃ガラスによる塩素の中和および塩ビ中の炭酸カルシウムの影響((3)環境対策,Session 7 環境対策・リサイクル)

Eco-friendly Technologies for Physical and Chemical Recycling of PVC-Related Wasteful Resources

The aim of this study is to enhance the recycled PVC related material property by formulation technology and develop the recycling product processing technology furthermore develop the chemical recycling technology for last stage of PVC wastes. The formulation technology is composed of pre-treatment (crushing, separation etc.) and post-treatment (material ratio, additives, stabilizer etc.) to enhance the recyclate property. The formulation for recycled PVC by application basis and processing technology is applied to produce the structural product for civil and construction application such as pipe fittings and water drainage cap for environmental waterway. Also chemical recycling technology for end life PVC scrap which causes environmental pollution by incineration or landfill is studied for producing hydrocarbon and hydrogen chloride for VCM.

ESSENTIAL CHARACTERISTICS OF PLASTICS WASTE FOR PYROLYSIS PROCESS: COMPARISON OF SELECTED PACKAGING PLASTICS AND PVC

The poor degradability of plastics has led to huge plastics deposit in a landfill of which pyrolysis technology has been proposed to solve plastics waste problem. This paper reports the study on characteristics of two kinds of plastic wastes: selected packaging plastics and PVC. Characterizations have been performed for investigating water content, ash content, and decomposition temperature. The results revealed that the water content of packaging plastic waste was 0.69 ± 0.11%, while PVC was 1.22 ± 0.24%. The ash contents are 2.36 ± 1.03 % and 27.24±1.73 % for packaging plastics waste and PVC waste respectively. Plastic waste from packaging application and PVC waste decomposed at a temperature of 300-500°C and 200-800°C respectively. Decomposition of PVC waste took place in three stages: 200-370°C, 370-525°C and 600-800°C. It is recommended that the pyrolysis process should be conducted in the range of 300-500°C for packaging plastic waste and 200-800°C for PVC waste.

Study on the behavior of heavy metals during thermal treatment of municipal solid waste (MSW) components.

Laboratory experiments were conducted to investigate the volatilization behavior of heavy metals during pyrolysis and combustion of municipal solid waste (MSW) components at different heating rates and temperatures. The waste fractions comprised waste paper (Paper), disposable chopstick (DC), garbage bag (GB), PVC plastic (PVC), and waste tire (Tire). Generally, the release trend of heavy metals from all MSW fractions in rapid-heating combustion was superior to that in low-heating combustion. Due to the different characteristics of MSW fractions, the behavior of heavy metals varied. Cd exhibited higher volatility than the rest of heavy metals. For Paper, DC, and PVC, the vaporization of Cd can reach as high as 75% at 500 °C in the rapid-heating combustion due to violent combustion, whereas a gradual increase was observed for Tire and GB. Zn and Pb showed a moderate volatilization in rapid-heating combustion, but their volatilities were depressed in slow-heating combustion. During thermal treatment, the additives such as kaolin and calcium can react or adsorb Pb and Zn forming stable metal compounds, thus decreasing their volatilities. The formation of stable compounds can be strengthened in slow-heating combustion. The volatility of Cu was comparatively low in both high and slow-heating combustion partially due to the existence of Al, Si, or Fe in residuals. Generally, in the reducing atmosphere, the volatility of Cd, Pb, and Zn was accelerated for Paper, DC, GB, and Tire due to the formation of elemental metal vapor. TG analysis also showed the reduction of metal oxides by chars forming elemental metal vapor. Cu2S was the dominant Cu species in reducing atmosphere below 900 °C, which was responsible for the low volatility of Cu. The addition of PVC in wastes may enhance the release of heavy metals, while GB and Tire may play an opposite effect. In controlling heavy metal emission, aluminosilicate- and calcium-based sorbents can be co-treated with fuels. Moreover, pyrolysis can be a better choice for treatment of solid waster in terms of controlling heavy metals. PVC and Tire should be separated and treated individually due to high possibility of heavy metal emission. This information may then serve as a guideline for the design of the subsequent gas cleaning plant, necessary to reduce the final emissions to the atmosphere to an acceptable level.

Effect of nano carbon additives on the microstructure of polyvinyl chloride heated up to 2000°C

ABSTRACTPolyvinyl chloride (PVC) is one of the most commonly used thermoplastic materials among worldwide polymer consumption. The PVC exhibits particular inherent properties such as low cost and high performance, it can be obtained from different techniques. PVC products will finally become waste. As a result, the quantity of waste PVC is gradually increasing. The waste product PVC can be converted to graphite. Graphitic structure was obtained by carbonization of polymers to 1000°C, and subsequent heating to 2000°C. In this study the effect of carbon nanotube (CNT) and carbon black additives on the graphitic microstructure of PVC polymer was investigated. The solution of PVC in tetrahydrofuran (THF) was prepared then additives were dispersed in solution by ultrasonic. The additives were applied in the concentration between 1 and 3wt%. Changes in graphitic microstructure were studied via Raman spectroscopy, X-ray diffraction, and Transmission electron microscopy (TEM). Morphology of microstructures studies with scanning electron microscopy (SEM). The results show that the additives do not develop the graphitic microstructure and do not improve the formation of flaky graphite crystals.