Recovery of hydrocarbon liquid from waste high density polyethylene by thermal pyrolysis
01 Dec 2011-Brazilian Journal of Chemical Engineering (Brazilian Society of Chemical Engineering)-Vol. 28, Iss: 4, pp 659-667
TL;DR: In this article, a simple pyrolysis reactor system was used to produce high-density polyethylene (HDPE) plastic as the material for pyrolyses, with the objective of optimizing the liquid product yield at a temperature range of 400oC to 550oC.
Abstract: Thermal degradation of waste plastics in an inert atmosphere has been regarded as a productive method, because this process can convert waste plastics into hydrocarbons that can be used either as fuels or as a source of chemicals. In this work, waste high-density polyethylene (HDPE) plastic was chosen as the material for pyrolysis. A simple pyrolysis reactor system has been used to pyrolyse waste HDPE with the objective of optimizing the liquid product yield at a temperature range of 400oC to 550oC. Results of pyrolysis experiments showed that, at a temperature of 450oC and below, the major product of the pyrolysis was oily liquid which became a viscous liquid or waxy solid at temperatures above 475oC. The yield of the liquid fraction obtained increased with the residence time for waste HDPE. The liquid fractions obtained were analyzed for composition using FTIR and GC-MS. The physical properties of the pyrolytic oil show the presence of a mixture of different fuel fractions such as gasoline, kerosene and diesel in the oil.
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TL;DR: In this article, the pyrolysis process for each type of plastics and the main process parameters that influenced the final end product such as oil, gaseous and char were reviewed.
Abstract: The global plastic production increased over years due to the vast applications of plastics in many sectors. The continuous demand of plastics caused the plastic wastes accumulation in the landfill consumed a lot of spaces that contributed to the environmental problem. The rising in plastics demand led to the depletion of petroleum as part of non-renewable fossil fuel since plastics were the petroleum-based material. Some alternatives that have been developed to manage plastic wastes were recycling and energy recovery method. However, there were some drawbacks of the recycling method as it required high labor cost for the separation process and caused water contamination that reduced the process sustainability. Due to these drawbacks, the researchers have diverted their attentions to the energy recovery method to compensate the high energy demand. Through extensive research and technology development, the plastic waste conversion to energy was developed. As petroleum was the main source of plastic manufacturing, the recovery of plastic to liquid oil through pyrolysis process had a great potential since the oil produced had high calorific value comparable with the commercial fuel. This paper reviewed the pyrolysis process for each type of plastics and the main process parameters that influenced the final end product such as oil, gaseous and char. The key parameters that were reviewed in this paper included temperatures, type of reactors, residence time, pressure, catalysts, type of fluidizing gas and its flow rate. In addition, several viewpoints to optimize the liquid oil production for each plastic were also discussed in this paper.
1,150 citations
Cites background from "Recovery of hydrocarbon liquid from..."
...The TG curve measures the weight change of substance as function of temperature and time [24]....
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...On the other hand, Kumar and Singh [24] have done the thermal pyrolysis study of HDPE using semi-batch reactor at higher temperature range of 400–550 C....
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...On the other hand, the DTG curve gives the information on the degradation step occurred during the process which is indicated by the number of peaks [24]....
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TL;DR: The existing techniques of pyrolysis, the parameters which affect the products yield and selectivity and the influence of different catalysts on the process are presented and major research gaps in this technology are identified.
Abstract: Plastic plays an important role in our daily lives due to its versatility, light weight and low production cost. Plastics became essential in many sectors such as construction, medical, engineering applications, automotive, aerospace, etc. In addition, economic growth and development also increased our demand and dependency on plastics which leads to its accumulation in landfills imposing risk on human health, animals and cause environmental pollution problems such as ground water contamination, sanitary related issues, etc. Hence, a sustainable and an efficient plastic waste treatment is essential to avoid such issues. Pyrolysis is a thermo-chemical plastic waste treatment technique which can solve such pollution problems, as well as, recover valuable energy and products such as oil and gas. Pyrolysis of plastic solid waste (PSW) has gained importance due to having better advantages towards environmental pollution and reduction of carbon footprint of plastic products by minimizing the emissions of carbon monoxide and carbon dioxide compared to combustion and gasification. This paper presents the existing techniques of pyrolysis, the parameters which affect the products yield and selectivity and identify major research gaps in this technology. The influence of different catalysts on the process as well as review and comparative assessment of pyrolysis with other thermal and catalytic plastic treatment methods, is also presented.
687 citations
Cites background from "Recovery of hydrocarbon liquid from..."
...HDPE pyrolysis oil has a reported CV of 42.9 MJ kg 1 (Kumar and Singh, 2011; Boundy et al., 2011; Ahmad et al., 2013, 2014)....
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TL;DR: In this article, the progress and challenges of the catalytic pyrolysis of plastic waste along with future perspectives in comparison to thermal pyrolynsis are reviewed. And the recommended solutions for these challenges include exploration of cheaper catalysts, catalyst regeneration and overall process optimization.
Abstract: This paper reviews the progress and challenges of the catalytic pyrolysis of plastic waste along with future perspectives in comparison to thermal pyrolysis. The factors affecting the catalytic pyrolysis process such as the temperature, retention time, feedstock composition and the use of catalyst were evaluated in detail to improve the process of catalytic pyrolysis. Pyrolysis can be carried out via thermal or catalytic routes. Thermal pyrolysis produces low quality liquid oil and requires both a high temperature and retention time. In order to overcome these issues, catalytic pyrolysis of plastic waste has emerged with the use of a catalyst. It has the potential to convert 70–80% of plastic waste into liquid oil that has similar characteristics to conventional diesel fuel; such as the high heating value (HHV) of 38–45.86 MJ/kg, a density of 0.77–0.84 g/cm3, a viscosity of 1.74–2.5 mm2/s, a kinematic viscosity of 1.1–2.27 cSt, a pour point of (−9) to (−67) °C, a boiling point of 68–352 °C, and a flash point of 26.1–48 °C. Thus the liquid oil from catalytic pyrolysis is of higher quality and can be used in several energy-related applications such as electricity generation, transport fuel and heating source. Moreover, process by-products such as char has the potential to be used as an adsorbent material for the removal of heavy metals, pollutants and odor from wastewater and polluted air, while the produced gases have the potential to be used as energy carriers. Despite all the potential advantages of the catalytic pyrolysis, some limitations such as high parasitic energy demand, catalyst costs and less reuse of catalyst are still remaining. The recommended solutions for these challenges include exploration of cheaper catalysts, catalyst regeneration and overall process optimization.
546 citations
TL;DR: In this article, the authors investigated the link between pyrolysis conditions, the chemical and mineralogical composition of their products and the benefits of pyroolysis in the waste management sector.
Abstract: The fundamentals of pyrolysis, its latest developments, the different conditions of the process and its residues are of great importance in evaluating the applicability of the pyrolysis process within the waste management sector and in waste treatment. In particular the types of residue and their further use or treatment is of extreme interest as they could become the source of secondary raw materials or be used for energy generation in waste treatments. The main area of focus of this paper is the investigation of the link between the pyrolysis conditions, the chemical and mineralogical composition of their products and the benefits of pyrolysis in the waste management sector. More specifically the paper covers the fast, intermediate and slow pyrolysis of organic waste and mixtures of inorganic and organic waste from households. The influence of catalysts during fast pyrolysis on the product yield and composition is not being considered in this review.
320 citations
TL;DR: In this paper, a four-cylinder direct injection diesel engine running at various blends of plastic pyrolysis oil and diesel fuel was tested and compared with diesel fuel operation.
Abstract: Plastic waste is an ideal source of energy due to its high heating value and abundance. It can be converted into oil through the pyrolysis process and utilised in internal combustion engines to produce power and heat. In the present work, plastic pyrolysis oil is manufactured via a fast pyrolysis process using a feedstock consisting of different types of plastic. The oil was analysed and it was found that its properties are similar to diesel fuel. The plastic pyrolysis oil was tested on a four-cylinder direct injection diesel engine running at various blends of plastic pyrolysis oil and diesel fuel from 0% to 100% at different engine loads from 25% to 100%. The engine combustion characteristics, performance and exhaust emissions were analysed and compared with diesel fuel operation. The results showed that the engine is able to run on plastic pyrolysis oil at high loads presenting similar performance to diesel while at lower loads the longer ignition delay period causes stability issues. The brake thermal efficiency for plastic pyrolysis oil at full load was slightly lower than diesel, but NOX emissions were considerably higher. The results suggested that the plastic pyrolysis oil is a promising alternative fuel for certain engine application at certain operation conditions.
199 citations
References
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TL;DR: In this article, the influence of zeolite catalytic upgrading of pyrolysis gases derived from polyethylene has been investigated in terms of the temperature of the catalyst and the yield and composition of derived hydrocarbon gases and oils.
Abstract: The influence of zeolite catalytic upgrading of the pyrolysis gases derived from the pyrolysis of polyethylene has been investigated. The yield and composition of the derived hydrocarbon gases and oils have been investigated in terms of the temperature of the catalyst. Polyethylene was pyrolysed in a fixed bed reactor and the pyrolysis gases passed to a secondary reactor containing Y-zeolite or zeolite ZSM-5 catalyst. The polyethylene was pyrolysed at 500°C and the temperature of the catalyst bed was 400, 450, 500, 550 or 600°C. The oils consisted of mainly aliphatic compounds represented by alkadiene, alkene and alkane hydrocarbons and their branched chain derivatives. The uncatalysed pyrolysis oil also contained low concentrations of aromatic hydrocarbons. After catalysis there was a marked increase in the concentration of aromatic compounds in the oil, which further increased in concentration as the temperature of catalysis was raised. The single ring compounds consisted of mainly toluene, ethylbenzene and xylenes and the two and three ring compounds were mainly, naphthalene and phenanthrene and their methyl derivatives. The Y-zeolite produced significantly greater concentration of aromatic hydrocarbons in the derived oils compared to when zeolite ZSM-5 catalyst was used.
301 citations
TL;DR: In this article, the co-pyrolytic behavior of plastic/biomass mixtures was investigated using a thermogravimetric analyser under a heating rate of 20°C/min from room temperature to 650°C, where the difference of weight loss (Δ W ) between experimental and theoretical ones, calculated as algebraic sums of those from each separated component, is about 6-12% at 530-650°C.
Abstract: Co-pyrolytic behaviours of plastic/biomass mixtures were investigated using a thermogravimetric analyser under heating rate of 20 °C/min from room temperature to 650 °C. The biomass sample selected was Chinese pine wood sawdust, while high density polyethylene (HDPE), low density polyethylene (LDPE) and polypropylene were selected as plastic samples. Results obtained from this comprehensive investigation indicated that plastic was decomposed in the temperature range 438–521 °C, while the thermal degradation temperature of biomass is 292–480 °C. The difference of weight loss (Δ W ) between experimental and theoretical ones, calculated as algebraic sums of those from each separated component, is about 6–12% at 530–650 °C. These experimental results indicate a significant synergistic effect during plastic and biomass co-pyrolysis at the high temperature region. In addition, a kinetic analysis was performed to fit thermogravimetric data, the global processes being considered as one to three consecutive first order reactions. A reasonable fit to the experimental data was obtained for all materials and their blends.
292 citations
"Recovery of hydrocarbon liquid from..." refers background in this paper
...starts decomposing at about 250°C against 477°C for pure HDPE (Zhou et al. 2006)....
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...Still, from the study reported by Chattopadhyay et al. (2008), it can be deduced that the mixture of HDPE, PP and PET starts decomposing at about 250°C against 477°C for pure HDPE (Zhou et al. 2006)....
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Book•
01 Jan 1979
TL;DR: In this paper, the authors provide a broad treatment of both the engineering and chemistry of catalytic cracking with zeolites and provide a thorough review of the relevant research literature, which is useful for engineers and scientists attuned to the ''systems approach''.
Abstract: This book should be particularly useful for the chemical or petroleum-refinery engineer who seeks a thorough, broad treatment of both the engineering and chemistry of catalytic cracking with zeolites. The treatment of the chemistry of cracking and of zeolites would also serve as an authoritative introduction for chemists. It is not the purpose of the book, however, to provide a thorough review of these chemistries and the relevant research literature. Perhaps that feature which makes the book unique is its successful exposition of the interactions among feedstocks, parent crude oils, catalyst, hardware, and operating conditions. It should have special appeal to those engineers and scientist attuned to the ''systems approach''.
244 citations
TL;DR: In this paper, the catalytic degradation of high-density polyethylene to hydrocarbons was studied over different zeolites, and the product range was typically between C3 and C15 hydrocarbon.
Abstract: The catalytic degradation of high-density polyethylene to hydrocarbons was studied over different zeolites. The product range was typically between C3 and C15 hydrocarbons. Distinctive patterns of product distribution were found with different zeolitic structures. Over large-pore ultrastable Y, Y, and β zeolites, alkanes were the main products with less alkenes and aromatics and only very small amounts of cycloalkanes and cycloalkenes. Medium-pore mordenite and ZSM-5 gave significantly more olefins. In the medium-pore zeolites secondary bimolecular reactions were sterically hindered, resulting in higher amounts of alkenes as primary products. The hydrocarbons formed with medium-pore zeolites were lighter than those formed with large-pore zeolites. The following order was found regarding the carbon number distribution: (lighter products) ZSM-5 < mordenite < β < Y < US-Y (heavier products). A similar order was found regarding the bond saturation: (more alkenes) ZSM-5 < mordenite < β < Y < US-Y (more alkan...
201 citations
"Recovery of hydrocarbon liquid from..." refers background in this paper
...Manos et al. (2000) studied the catalytic degradation of high density polyethylene to hydrocarbons over different zeolites....
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TL;DR: In this paper, the authors investigated the catalytic degradation of waste high-density polyethylene (HDPE) to hydrocarbons by ZSM-5, zeolite-Y, mordenite and amorphous silica-alumina.
Abstract: Catalytic degradation of waste high-density polyethylene (HDPE) to hydrocarbons by ZSM-5, zeolite-Y, mordenite and amorphous silica–alumina were carried out in a batch reactor to investigate the cracking efficiency of catalysts by analyzing the oily products including paraffins, olefins, naphthenes and aromatics with gas chromatography/mass spectrometry (GC/MS). Catalytic degradation of HDPE with zeolite-Y, mordenite and amorphous silica–alumina yielded 71–82 wt.% oil fraction, which mostly consisted of C6–C12 hydrocarbons, whereas ZSM-5 yielded much lower 35% oil fraction, which mostly consisted of C6–C12 hydrocarbons. Both all zeolites and silica–alumina increased olefin content in oil products, and ZSM-5 and zeolite-Y particularly enhanced the formation of aromatics and branched hydrocarbons. ZSM-5 among zeolites showed the greatest catalytic activity on cracking waste HDPE to light hydrocarbons, whereas mordenite produced the greatest amount of coke. Amorphous silica–alumina also showed a great activity on cracking HDPE to lighter olefins in high yield, but no activity on aromatic formation.
176 citations
"Recovery of hydrocarbon liquid from..." refers background or methods in this paper
...Seo et al. (2003) studied the catalytic degradation of waste high density polyethylene to hydrocarbons by ZSM-5, zeolite-Y, mordenite and amorphous silica-alumina in a batch reactor and investigated the cracking efficiency of catalysts by analyzing the oily products, including paraffins, olefins, naphthenes and aromatics, with gas chromatography/mass spectrometry (GC/MS)....
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...Seo et al. (2003) studied the catalytic degradation of waste high density polyethylene to hydrocarbons by ZSM-5, zeolite-Y, mordenite and amorphous silica-alumina in a batch reactor and investigated the cracking efficiency of catalysts by analyzing the oily products, including paraffins, olefins,…...
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