润滑油对轮胎主要成分催化裂解行为的影响

本文研究了润滑油对轮胎的重要组成原料:天然橡胶、聚丁二烯橡胶和丁苯橡胶催化裂解行为的影响.研究发现润滑油的加入明显增强了催化剂ZSM-5对聚丁二烯橡胶的催化裂解作用:液体收率从69.0％提高到83.4％,残渣收率从17.0％降至3.2％;润滑油的加入也提高了丁苯橡胶催化裂解的反应速率,液体产物中的轻油组分由67.5％增...     

Characterization of vacuum gas oil-low density polyethylene blends by thermogravimetric analysis

The study of the catalytic pyrolysis of mixtures of fuel and polymers is interesting in order to explore the possibility of using commercial fluid catalytic cracking (FCC) units or similar processes for recycling plastic wastes. In this work, different samples of vacuum gas oil (VGO), polyethylene (PE) and vacuum gas oil-polyethylene blends (VGO-PE) have been studied by thermogravimetric analysis. Vacuum gas oil-polyethylene blends with 1, 2.5, 5, 7.5 and 10% w/w of PE were prepared by continuously stirring for 120 min, at 60 rpm at 120 °C, and afterwards, the effect of different catalysts (HZSM-5, HUSY, HBeta zeolites, FCC catalysts and Al-MCM-41) on the decomposition of these mixtures was studied. Moreover, the deposition of coke over each catalyst was studied by thermogravimetric analysis in an oxidant atmosphere. The catalytic pyrolysis behaviour of the VGO-PE mixtures indicates a two-step process, the degradation of the VGO and the PE fraction being almost independent. The degradation or evaporation of the VGO fraction is only slightly affected by the presence of the catalyst, whereas the PE fraction showed similar behaviour as that already described in the literature for the pure polymer. The results show that the HBeta zeolite is the most active catalyst for the decomposition of the mixtures, and that the ZSM-5 zeolite is the catalyst with the lowest amount of coke formation. These results are in very good agreement with the structural characteristics of the different catalysts studied, i.e., with their pore size and acidity.     

Copyrolysis of scrap tires with oily wastes

In this study, the conversion of hazardous wastes into liquid fuels was investigated. The pyrolysis of bilge water oil and oil sludge from ships, scrap tires and their blends was carried out at 400 and 500 °C in absence and presence of catalyst. A commercial fluid catalytic cracking catalyst and Red Mud were used as catalyst. Pyrolysis products were separated as gas, oil and char. The pyrolytic oils were characterized by using gas chromatography-mass selective detector (GC-MSD) and ¹H nuclear magnetic resonance (¹H-NMR). The effect of temperature and catalyst on the product distribution and the composition of oil from pyrolysis were investigated. Co-pyrolysis of scrap tire with oily wastes from ships produced oil that could be used as fuel, while its pyrolysis alone produced oil that could be used as a chemical feedstock. The results obtained in this study showed that co-pyrolysis of oily wastes with scrap tires could be an environmentally friendly way for the transformation of hazardous wastes into valuable products such as chemicals or fuels.     

Thermal degradation of polyethylene and polystyrene from the packaging industry over different catalysts into fuel-like feed stocks

Thermal degradation of waste polymers was carried out as a suitable technique for converting plastic polymers into liquid hydrocarbons, which could be used as feed stock materials. The catalytic degradation of waste plastics (polyethylene and polystyrene) was investigated in a batch reactor over different catalysts (FCC, ZSM-5 and clinoptillolite). The effects of catalysts and their average grain size on the properties of main degradation products (gases, gasoline, diesel oil) are discussed. The temperature range of 410-450 °C was used in the process. Both equilibrium FCC catalyst and natural clinoptilolite zeolite catalyst had good catalytic activity to produce light hydrocarbon liquids, and ZSM-5 catalyst produced the highest amount of gaseous products. Gases and liquids formed in cracking reactions were analyzed by gas chromatography. The liquid products consisted of a wide spectrum of hydrocarbons distributed within the C₅-C₂₈ carbon number range depending on the cracking parameters. The composition of hydrocarbons had linear non-branched structure in case of polyethylene, while from polystyrene more aromatics (ethyl-benzene, styrene, toluene, and benzene) were produced. The yields of volatile products increased with increasing degradation temperature. The olefin content of liquids was measured with an infrared technique and an olefin concentration of 50-60% was observed. The concentration of unsaturated compounds increased with decreasing temperature, and in the presence of catalysts. The activation energies were calculated on the basis of the composition of volatile products. The apparent activation energies were decreased by catalysts and catalyst caused both carbon-chain and double bond isomerisation.     

The effects of magnesium and aluminium ions’ additions on the kinetics of titanium dioxide structural transformation

Catalytic fast pyrolysis analysis of miscanthus over HZSM-5, La/ZSM-5, and Ca/ZSM-5 was performed using pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS). The characteristics of the catalysts used in this study were analyzed using XRD, SEM, Pyridine IR, ICP, and N₂ adsorption. The catalytic performance of the three catalysts was evaluated in terms of deoxygenation. Py–GC/MS results show that with increasing temperature, pyrolysis vapor yield first increased and then decreased. This may be due to secondary cracking at higher temperatures, which produced more gas products. Moreover, hydrocarbon content increased with rising temperature. The optimum temperature was found to be 600 °C, which resulted in the greatest liquid yield. All three catalysts increased pyrolysis vapor yield by about 30 %. Moreover, the hydrocarbon content of miscanthus increased from 6 to 39 %, 46, and 44 %, respectively, when HZSM-5, La/ZSM-5, and Ca/ZSM-5 were applied. In conclusion, the three catalysts were effective for deoxygenation of pyrolysis vapor yield. Considering both economic and catalytic upgrading effect, Ca/ZSM-5 may be the best catalyst.     

催化热解废轮胎制衍生油

催化热解废轮胎对于资源利用及环境保护具有重要意义,近年来引起人们关注.在废轮胎胶粉热解反应中加入催化剂,不仅会加速胶粉裂解速率,缩短反应时间,而且可以通过催化剂择形催化改变产物分布,从而提高目的产物衍生油的收率和性能.国内外对废轮胎催化热解已做了大量研究,以期提高衍生油中高附加值单环芳烃的含量,同时降低S, N和Cl含量,虽然已取得较大进展,但衍生油收率较低,大大降低了该技术的可行性.
　　本文采用带搅拌器的1000 mL不锈钢反应器,在常压条件下研究了反应温度和催化剂类型对废轮胎胶粉热解反应及产物衍生油性能的影响,通过元素分析、馏程模拟和色谱-质谱等表征手段检测了衍生油的理化性能.结果表明,在废轮胎胶粉热解反应过程中,随反应温度上升,出油速率先增加后降低.至500 oC时,热解衍生油收率最高达55.65 wt%,所得衍生油呈黑棕色,具有轻质油含量低、S和N含量高、粘度低和流动性好的特点,其轻质芳烃含量低,却含有大量可以转变为芳烃的脂肪烃类.因此,为了提高衍生油中轻质油和轻质芳烃收率,降低S和N含量,尽量维持较高的衍生油收率,在热解反应过程中引入少量ZSM-5, USY,β, SAPO-11和ZSM-22等常见催化剂,利用催化剂独特的孔道结构和酸分布,达到定向催化和转化的目的,提高轻质芳烃含量.同时,为了克服催化剂与胶粉难以接触进行反应的问题,在反应温度升至200 oC时,维持一定时间保证胶粉发生溶胀和液化反应形成液体烃类,使得催化剂不仅能够均匀分散于液体烃中与其接触进行反应,而且有效提高了反应物料与催化剂之间传质传热效率,使得裂解反应在均相中进行,降低因传热不均匀而造成的结焦和过度裂化反应.在催化热解过程中,1.0 wt%催化剂的加入可明显缩短反应时间,在保证衍生油收率基本不变的情况下,获得的衍生油呈黄棕色,轻质油收率较高为70–75 wt%, S和N含量分别降至0.3–0.58wt%和0.78–1.0 wt%.以具有较高酸性和孔径分布的ZSM-5, USY,β和SAPO-11为催化剂时,衍生油中总芳烃含量可达到50 wt%,其中单环芳烃含量高达45 wt%.     

Fuel oil from ABS using a tandem PEG-enhanced denitrogenation-pyrolysis method: Thermal degradation of denitrogenated ABS

Thermal degradation of ABS and denitrogenated ABS samples (DABS), prepared by sequential hydrolysis of ABS using PEG/NaOH, has been investigated under inert gas and at atmospheric pressure in a temperature range between 40 and 700 °C, by means of TGA, TGA-IR, and TGA-MS, to study the link between original structure of DABS and eventual pyrolysis. For DABS, thermal decomposition begins at the side groups of -CONH₂ and/or -COOH, resulting in a lower initial degradation temperature of DABS (around 330 °C) relative to ABS (372.5 °C). Moreover, less HCN and acrylonitrile evolve from the DABS samples, while the evolution of CO₂ starts earlier and becomes more important, in line with the decreased number of -CN groups and the increased number of -COOH functional groups due to hydrolysis. The results from thermo-analytical experiments were confirmed by batch pyrolysis tests: the nitrogen content of oil produced from DABS pyrolysis is much lower, compared with that from ABS, proving that effective denitrogenation of ABS prior to pyrolysis is beneficial to the quality of pyrolysis oil.     

Thermal and catalytic degradation of pyrolytic oil from pyrolysis of municipal plastic wastes

Thermal and catalytic degradation of pyrolytic oil obtained from the commercial rotary kiln pyrolysis plant for municipal plastic waste was studied by using fluid catalytic cracking (FCC) catalyst in a bench scale reactor. The characteristics of raw pyrolytic oil and also thermal and catalytic degradation of pyrolytic oil using FCC catalyst (fresh and spent FCC catalyst) under rising temperature programming was examined. The experiments were conducted by temperature programming with 10 °C/min of heating rate up to 420 °C and then holding time of 5 h. During this programming, the sampling of product oil was conducted at a different degradation temperature and also different holding time. The raw pyrolytic oil showed a wide retention time distribution in GC analysis, from 5 of carbon number to about 25, and also different product characteristics with a comparison of those of commercial oils (gasoline, kerosene and diesel). In thermal degradation, the characteristics of product oils obtained were influenced by reaction temperature under temperature programming and holding time in the reactor at 420 °C. The addition of FCC catalyst in degradation process showed the improvement of liquid and gas yield, and also high fraction of heavy hydrocarbons in oil product due to more cracking of residue. Moreover, the characteristic of oil product in catalytic degradation using both spent and fresh FCC catalysts were similar, but a relatively good effect of spent FCC catalyst was observed.     

Copyrolysis of naphtha with polyalkene cracking products; the influence of polyalkene mixtures composition on product distribution

The steam cracking (copyrolysis) of naphtha with oils/waxes from thermal decomposition of polyalkenes has been investigated as a process for chemical recycling of plastic wastes. High-density polyethylene (HDPE), two-component mixture (LDPE/PP) and three-component mixture (HDPE/LDPE/PP) were thermally decomposed in a batch reactor at 450 °C, thus forming oil/wax products. Subsequently, these products were dissolved in heavy naphtha in the amount of 10 mass% to obtain steam cracking feedstock. The composition of gaseous and liquid products during copyrolysis was studied at 780 °C and 820 °C in dependence on residence time from 0.08 s to 0.51 s. The obtained results were compared with the product composition from steam cracking of naphtha at identical experimental conditions. The decomposition of polyalkene oils/waxes during copyrolysis was confirmed on the basis of analysis of liquid products. It was shown that more ethene and propene was formed during copyrolysis of oil/wax from HDPE in comparison with naphtha and both mixtures and so oil/wax from HDPE seems to be favourable component of steam cracking feedstock. There were slight differences between product compositions from copyrolysis of two- and three-component mixtures. The presence of HDPE in three-component mixture supported formation of gas and ethene. The presence of oil/wax form PP enhanced formation of propene and branched alkenes. For both type of polyalkenic mixtures the yields of desired low molecular alkenes and alkanes were higher or approximately the same as from naphtha. The results confirm suitability of oils/waxes from polyalkenes as a co-feed for steam cracking units.     

Characterization of the liquid product recovered through pyrolysis of PMMA-ABS waste

Thermal decomposition of waste polymethylmethacrylate-acrylonitrile-butadiene-styrene (PMMA-ABS) blend has been carried out using analytical and lab-scale pyrolysis methods in order to identify the substantial components appearing in the liquid product. Additionally decomposition characteristics of the blend have been investigated regarding the possible interrelation between the two components during the pyrolysis. The interactions between PMMA and ABS seem to modify the decomposition characteristics of the ABS, resulting in a lower degradation temperature than that of pure ABS. Moreover the simultaneous decomposition results in recombination of the products yielding new volatile compounds. During batch pyrolysis relatively high amount of gas production was observed, that is in contradiction with the results obtained by analytical pyrolysis and the data found in the literature where pyrolysis of the PMMA as well as the ABS was reported to yield low amount of gas products. The liquid product retrieved from thermal decomposition has been analyzed with respect to the possible utilization as a propellant. Hence aside from the investigation of contained elements and compounds, determination of density, viscosity, research octane number (RON), calorific value, and gaseous emissions has been carried out as well. The relatively high yield (65 wt%), and outstanding compression tolerance (RON = 110.2) observed at the pyrolysis oil make it a feasible fuel admixture.     

Microwave pyrolysis of straw bale and energy balance analysis

The compressed wheat and corn straw bale were pyrolyzed on a microwave heating device self-designed and built with respect to the time-resolved temperature distribution, mass loss and product properties. Considering scale up and technology promotion of microwave pyrolysis (MWP), the investigations on electricity consumption and energy balance of MWP were carried out emphatically. The results indicated that MWP had obvious advantages over conventional pyrolysis, such as heating rapid and more valuable products obtained. The distribution of pyrolysis products such as gas, liquid and char was close to 1:1:1 due to the medium pyrolysis temperature and the slow heating rate, which was not favorable for the formation of gas and/or liquid products. The content of H₂ attained the highest value of 35 vol.% and syngas (H₂ and CO) was greater than 50 vol.%. The electricity consumption of MWP was between 0.58 and 0.65 kW h (kg straw)⁻¹ and with the increase of microwave power, the electricity consumption required for pyrolysis of unit mass of straw increased. The minimum microwave power for MWP was about 0.371 kW (kg straw)⁻¹ and the proportion of heat loss and conversion loss of electricity to microwave energy occupied in the total input energy was 42%. Data and information obtained are useful for the design and operation of pyrolysis of large-sized biomass via microwave heating technology.     

Investigation of catalytic degradation of high-density polyethylene by hydrocarbon group type analysis

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.     

Microwave-assisted extraction at atmospheric pressure coupled to different clean-up methods for the determination of organophosphorus pesticides in olive and avocado oil

An effective extraction method was devised for the determination of organophosphorus pesticides (OPPs) in olive and avocado oil samples, using atmospheric pressure microwave-assisted liquid–liquid extraction (APMAE) and solid-phase extraction or low-temperature precipitation as clean-up step. A simple glass system equipped with an air-cooled condenser was designed as an extraction vessel. The pesticides were partitioned between acetonitrile and oil solution in hexane. Analytical determinations were carried out by gas chromatography-flame photometric detection and gas chromatography–tandem mass spectrometry, using a triple quadrupole mass analyzer, for confirmation purposes. Several factors influencing the extraction efficiency were investigated and optimized through fractional factorial design and Doehlert design. Under optimal conditions the recovery of pesticides from oil at 0.025 μg g⁻¹ ranged from 71% to 103%, except for fenthion in avocado oil, with RSDs ≤13% (n = 5). The LOQ for the entire method ranged from 0.004 to 0.015 μg g⁻¹. Finally, the proposed method was successfully applied to the extraction and determination of the selected pesticides in 20 commercially packed extra virgin olive oils and four commercially packed avocado oils produced in Chile. Detectable residues of different OPPs were observed in 85% of samples.     

Feedstock recycling of synthetic and natural rubber by pyrolysis in a fluidized bed

An indirect heated fluidized bed process has been used for the pyrolysis of synthetic and natural rubber. The throughput capacity for the continuously running plant was 500–3000 g/h. The results are compared to a pilot plant for the pyrolysis of whole tires. Beside the recovery of oil and carbon black it was another goal of the study to investigate how much monomer material such as isoprene and isobutene can be obtained from synthetic and natural rubber. The pyrolysis parameters were optimized such as pyrolysis temperature, kind of fluidizing gas, and residence time of the gas in the pyrolysis reactor. Main products of the pyrolysis of tires are an aromatic-rich oil and carbon black, which can be reused. While it was possible to obtain only 2–4 wt% of isobutene, the isoprene content reached 22 wt% from natural rubber.     

Essential Quality Attributes of Tangible Bio‐Oils from Catalytic Pyrolysis of Lignocellulosic Biomass

This review covers the characteristics of pyrolysis and catalytic pyrolysis bio‐oils by focusing on the fundamental factors that determine bio‐oil upgradability. The abundant works on the subject of bio‐oil production from lignocellulosic biomass were studied to establish the essential attributes of the bio‐oils for assessment of the oil stability and upgradability. Bio‐oils from catalytic pyrolysis processes relating to catalysts of different compositions and structures are discussed. A general relationship between the higher heating value and the oxygen content in the catalytic pyrolysis oils exists, but this relationship does not apply to the thermal pyrolysis oil. Reporting bio‐oil yield is meaningful only when the oxygen content of the oil is measured because the pyrolytic oil stability is mainly determined by the oxygen content. Isoenergy plot that associates bio‐oil yield with oxygen content is presented and discussed.     

Vacuum pyrolysis of intruder plant biomasses

Biomass from three invasive plant species of the Western Karoo region in South Africa, namely Kraalbos, Schotzbos and Asbos, was treated by vacuum pyrolysis. The influence of temperature, pyrolysis time, pressure and initial moisture content on the bio-oil and charcoal yields were investigated. Asbos with the largest ash content, 19.9 wt.%, gave chars with an ash content between 40 wt.% and 44 wt.% making it difficult to use commercially. Vacuum pyrolysis of Kraalbos resulted in producing a biochar with a HHV of 23.0-25.5 MJ/kg and an ash content of 13-19 wt.% which compared favourable with commercial charcoal. The bio-oils from both Kraalbos and Schotzbos showed promise as potential heating oil with a HHV of 21.6-26.9 MJ/kg. The tarry phase contained a number of phenolic compounds that can be separated and shows promise as a feedstock for upgrading. Finally ageing which acts on the lignocellulosic structure of biomasses decreased the charcoal and oil yields from the vacuum pyrolysis of intruder plants.     

Study of the pyrolysis of municipal solid waste for the production of valuable products

To obtain information on the potential of thermal conversion (pyrolysis) of municipal solid waste (MSW), a thermogravimetric study (TGA) is performed in a stream of nitrogen. Based on TGA results, pyrolysis experiments are carried out in a semi-batch reactor under inert nitrogen atmosphere. Slow pyrolysis is performed up to 550 °C (heating rate of 4 °C/min). Fast pyrolysis is performed at 450, 480, 510 and 550 °C and different input transfer rates (12 or 24 g material/min). The pyrolysis products are studied on composition and yield/distribution and investigated for their use as valuable product.The liquid obtained by slow pyrolysis separates spontaneously in a water rich product and an oily product. For all fast pyrolysis conditions, a viscous, brown oil which contains a poly(ethylene-co-propylene) wax is obtained. Composition analyses by GC/MS of the oil products (slow/fast pyrolysis) show that aliphatic hydrocarbons are the major compounds. The pyrolysis oils have high calorific value (between 35 and 44 MJ/kg), low wt% of water (around 6 wt%) and a low O/C value (between 0.2 and 0.3). The presence of waxy material is probably due to incomplete breakdown of poly(ethylene-co-propylene) present in MSW under study. The optimal pyrolysis conditions, regarding to oil yield, fuel properties, and wax yield is fast pyrolysis at 510 °C with 24 g material/min input transfer rate. The fast pyrolysis gases contain mainly hydrocarbons and have an averaged LHV around 20 MJ/Nm³. ICP-AES analyses of pyrolysis products reveal that almost none of the metals present in MSW are distributed within the liquid fractions.     

Investigation of physicochemical properties of biooils produced from yellow poplar wood (Liriodendron tulipifera) at various temperatures and residence times

Fast pyrolysis of yellow poplar wood (Liriodendron tulipifera) was performed under different temperature ranges and residence times in a fluidized bed reactor to maximize the yield of biooil. In this study, the pyrolysis temperature ranged from 400 °C to 550 °C, and the residence time of pyrolysis products was controlled between 1.2 and 7.7 s by inert nitrogen gas flow. The results revealed that the distribution of thermal degradation products (biooil, biochar, and gas) from the woody biomass was heavily influenced by pyrolysis temperature, as well as residence time. The highest yield of biooil was approximately 68.5 wt% (wet basis), with pyrolysis conditions of 500 °C and 1.9 s of residence time. Water content of the biooils produced at different temperatures was 25-30 wt%, and their higher heating values were estimated to be between 15 MJ/kg and 17 MJ/kg. Using GC/MS analysis, 30 chemical components were identified from the biooil, which were classified into 5 main groups: organic acids, aldehydes, ketones, alcohols, and phenols. In addition, biochar was produced as a co-product of fast pyrolysis of woody biomass, approximately 10 wt%, at temperatures between 450 °C and 550 °C. The physicochemical features of the biochar, including elemental analysis, higher heating values, and morphological properties by SEM, were also determined.     

Bio-oil production from Onopordum acanthium L. by slow pyrolysis

In this study, the usability of the plant thistle, Onopordum acanthium L., belonging to the family Asteraceae (Compositae), in liquid fuel production has been investigated. The experiments were performed in a fixed-bed Heinze pyrolysis reactor to investigate the effects of heating rate, pyrolysis temperature and sepiolite percentage on the pyrolysis product yields and chemical compositions. Experiments were carried out in a static atmosphere with a heating rate of 7 °C/min and 40 °C/min, pyrolysis temperature of 350, 400, 500, 550 and 700 °C and particle size of 0.6 < D_p < 0.85 mm. Catalyst experiments were conducted in a static atmosphere with a heating rate of 40 °C/min, pyrolysis temperature of 550 °C and particle size of 0.6 < D_p < 0.85 mm. Bio-oil yield increased from 18.5% to 27.3% with the presence of 10% of sepiolite catalyst at pyrolysis temperature of 550 °C, with a heating rate of 40 °C/min, and particle size of 0.6 < D_p < 0.85 mm. It means that the yield of bio-oil was increased at around 48.0% after the catalyst added. Chromatographic and spectroscopic studies on the bio-oil showed that the oil obtained from O. acanthium L. could be used as a renewable fuels and chemical feedstock.     

PP和PVC混合塑料的降解及脱氯研究

对聚丙烯(PP)和聚氯乙烯(PVC)混合物在380 ℃下的热降解进行了研究。检测了PP和PVC混合塑料降解液体产物的沸点分布，并用铁氧化物作为固体吸附剂以除去产品中的氯元素。同时还研究了该混合物在ZSM-5催化剂存在下的降解，与热降解相比，ZSM-5催化剂加快了降解的速率，并且降低了液体产品的沸点。铁氧化物α-FeOOH和Fe3O4则能有效地降低产品中的氯含量。