The influence of catalyst regeneration on the composition of zeolite-upgraded biomass pyrolysis oils

The composition of oils derived from the on-line, low pressure zeolite upgrading of biomass pyrolysis oils from a fluidized bed pyrolysis unit have been investigated in relation to the regeneration of the zeolite catalyst. The catalyst used was H-ZSM-5 zeolite. The gases were analysed by packed column gas chromatography. The composition of the oils before catalysis and after catalyst upgrading were analysed by liquid chromatography fractionation, followed by coupled gas chromatography—mass spectrometry of each fraction. In particular, the aromatic and oxygenated aromatic species were identified and quantified. In addition, the oils were analysed for their elemental composition and molecular weight range using size exclusion chromatography. Before catalysis the biomass pyrolysis oil was highly oxygenated but after catalysis a highly aromatic oil was formed with high concentrations of monocyclic aromatic hydrocarbons. In addition, significant concentrations of polycyclic aromatic hydrocarbons (PAH) were formed. Regeneration of the zeolite catalyst showed that continued regeneration reduced the effectiveness of the catalyst in converting biomass pyrolysis oils to an aromatic product. Elemental analysis of the upgraded oils showed an increase in the oxygen content of the oil with increasing regeneration of the catalyst. The molecular weight range of the oils was found to decrease markedly after catalysis, but continued regeneration of the catalyst increased the molecular weight range of the upgraded oils. Detailed analysis of the uncatalysed oils showed they contained low concentrations of aromatic and PAH species which markedly increased in concentration after catalysis. The overall effect of increasing catalyst regeneration was a decrease in the concentration of aromatic hydrocarbons and PAH. Also as the catalyst was regenerated, the number of methyl groups on the parent single ring aromatic compound or PAH increased. The oxygenated aromatic species in the oil before catalysis were mainly, phenols and benzenediols and their alkylated homologues. After catalysis some of the oxygenated species were reduced and some increased in concentration. A dual mechanistic route is suggested for the formation of aromatics and PAH during the catalytic upgrading of biomass pyrolysis oils: (1) the formation of low-molecular-weight hydrocarbons on the catalyst which then undergo aromatization reactions to produce aromatic hydrocarbons and PAH; (2) deoxygenation of oxygenated compounds found in the non-phenolic fraction of the pyrolysis oils which directly form aromatic compounds.     

Catalytic pyrolysis of tyres: influence of catalyst temperature

Two stage pyrolysis–catalysis of used tyres was undertaken to upgrade the derived oil to a highly aromatic oil suitable to be used as a chemical feedstock rather than a liquid fuel. The tyres were pyrolysed in a fixed bed reactor and the evolved pyrolysis gases were passed through a secondary fixed bed reactor containing zeolite catalyst. The pyrolysis reactor was maintained at 500 °C and the influence of catalyst temperature between 430 and 600 °C on the yield and composition of the derived oils was examined. Two zeolite catalysts were examined; a Y-type zeolite catalyst and zeolite ZSM-5 catalyst of differing pore size and surface activity. The influence of the catalyst was to reduce the yield of oil with a consequent increase in the gas yield and formation of coke on the catalyst. Single ring aromatic hydrocarbons, benzene, toluene and xylenes present in the oils showed a marked increase in the presence of the catalyst. Naphthalene and alkylated naphthalenes were also analysed and showed a similar marked increase in the concentration when a catalyst was present. The Y-type zeolite catalyst of larger pore size and higher surface activity was found to produce higher concentrations of aromatic compounds compared to the ZSM-5 catalyst. Increasing the catalyst temperature resulted in significant changes in the concentration of benzene, toluene, xylenes, naphthalene and the alkylated naphthalenes.     

催化裂化油浆系统结焦原因及预防措施

介绍1.8 Mt/h催化裂化装置油浆系统结焦形成的机理并分析油浆系统结焦的原因,结合装置运行的实际操作以及经验,提出预防油浆系统结焦的措施。催化裂化油浆结焦的原因主要由一些稠环化合物具有热缩和反应活性,这些稠环化合物吸附、粘附在催化剂上并发生缔合或缩合反应并生成由有机物与无机物组成的混合结垢催化剂、焦炭及少量金属化合物。通过降低油浆密度、降低分馏塔底温度、加大油浆阻垢剂注入量等措施可以有效地预防油浆系统结焦。     

Supercritical extraction of scrap tire with different solvents and the effect of tire oil on the supercritical extraction of coal

Scrap tires are a growing environmental problem because they are not biodegradable. In this investigation, supercritical extraction of scrap tire and co-processing of coal with tire oil were studied. In the first stage, tires were extracted at 400 °C with a number of different solvents. The effects of the hydrocarbon and polar solvents used under the supercritical extraction conditions on the conversion and oil product of tire were determined, and it was observed that all volatile organic material of the scrap tire was converted to the liquid or gas product. In the second stage, coal and supercritical extracted tire oil (SCETO) samples were extracted with different solvents using various tire oil/coal ratios. In general, the use of tire oil generated an improvement for coal conversion. Further, the oil yield was higher than those of coal alone runs. The SCETOs were characterized using spectroscopic (FTIR) and chromatographic analytical techniques (GC–MS). GC–MS, and FTIR results showed that the oils are mainly comprised of alkyl aromatic species. A significant amount of alkyl-substituted phenol compounds was also found to be present in the oils.     

Aromatic and hetero-aromatic compositional changes during catalytic hydrotreatment of shale oil

Oil shale from the Kimmeridge Clay, of Jurassic age from the UK was pyrolysed in a 5 kg fixed bed reactor at 525°C in a nitrogen atmosphere. The derived shale oil was then hydrotreated at 15.0 Mpa pressure and 400°C in a stirred reactor with a nickel–molybdenum (Ni–Mo) catalyst and residence times from 8 to 56 h. The shale oils were analysed for polycyclic aromatic hydrocarbons (PAH) and for nitrogen-PAH (PANH) and sulphur-PAH (PASH), before and after hydrotreatment. The results showed that generally the higher molecular weight three and four ring PAH decreased with increasing hydrotreatment time, however, single ring aromatic compounds and two ring PAH were increased. Nitrogen and sulphur containing PAH were significantly reduced in concentration in the oils with increasing hydrotreatment time to reach negligible concentrations after 56 h. The reduction in PANH and PASH coincided with a reduction in the overall nitrogen and sulphur contents of the oils.     

Investigations into the characteristics of oils produced from co-pyrolysis of biomass and tire

Co-pyrolysis of wood biomass and waste tire with such catalysts as SBA-15, MCM-41 and HZSM-5 was carried out in a fixed-bed reactor. The influences of the mixture composition on liquid yield and characteristics of the oil were investigated. The properties of the oil were determined by gel permeation chromatograph (GPC), elemental analyzer (EA), thermal analyzer (TA), densimeter, ubbelohde viscosimeter and compared with that of diesel oil 0#. The contents of the polycyclic aromatic hydrocarbons (PAHs) in the oils were also determined by gas chromatograph (GC). The result shows that co-pyrolysis is in favor of inhibiting the formation of polycyclic aromatic hydrocarbons (PAHs) produced from tire. There exist a hydrogen transfer and a synthetic effect during co-pyrolysis of the biomass and tire. They improve the quality of the oil. SBA-15 as a catalyst is more significant than MCM-41 or HZSM-5 for reducing the density and viscosity of the oil and it can effectively decompose some large molecular compounds into small ones.     

1H n.m.r. study of tars from flash pyrolysis of three Australian coals

The structure and composition of tars from the flash pyrolysis of one brown and two bituminous Australian coals were investigated by ¹H n.m.r. spectroscopy. Reaction times in a fluidized bed were about 1 s. For each tar the aromatic hydrogen content increases slightly with pyrolysis temperature up to ≈650 °C and then rapidly up to 900 °C. The aromatic carbon content increases rectilinearly with temperature. The yield of aromatic carbon reaches a maximum at 600–700 °C, and then decreases; the yield of aromatic hydrogen is independent of temperature. The proportion of aromatic material with condensed ring structures increases with temperature. Three temperature zones of reactivity can be recognized. Polymethylene chains and aromatic groups are stable up to 600 °C. Between 600 and 700 °C aliphatic substituents, other than α groups, decompose; between 700 and 900 °C α-aliphatic and aromatic groups also decompose, resulting in lower yields of tar.     

东北连翘鲜花精油的GC-MS分析

采用同时蒸馏萃取(SDE)法提取东北连翘鲜花精油,气相色谱-质谱法(GC-MS)分析精油的化学组分,考察不同溶剂对结果的影响。结果表明,SDE石油醚萃取得到的东北连翘鲜花精油得率为0.69%,鉴定得到28种成分,GC含量最高的化合物为二十五烷(28.65%),其次是Z-9-二十三烯(27.82%)。SDE正己烷萃取得到的东北连翘鲜花精油得率为0.81%,鉴定得到44种成分,GC含量最高的化合物为Z-9-二十三烯(47.16%),其他香料化合物如肉豆蔻醛(0.97%)、石竹烯(0.05%)等。两种精油的共有成分Z-9-二十三烯可用作家蝇性引诱剂。     

顺丁橡胶装置回收单元溶剂油脱水塔换热的优化设计

溶剂油回收是多组分精馏过程,利用混合液中各组分的挥发度不同,在一定压力、温度下,在塔中经多次部分冷凝和部分蒸发,从而达到各组份分离的目的。粗溶剂油脱水采用非均相共沸,水与部分溶剂及丁二烯在一定温度、压力下产生共沸从塔顶蒸出,经冷凝器冷凝后,水与物料在回流罐中分层,水从设备底部排放掉,达到脱水的目的。溶剂油脱水塔,现塔顶温度约为100℃气相用循环水冷凝、冷却到40℃左右,而进料约40℃溶剂油用低压蒸汽加热。改为塔顶气相与进料两者进行换热,不但能节能低压蒸气、而且能减少循环水用量。     

The pyrolysis of scrap automotive tyres: The influence of temperature and heating rate on product composition

Shredded automotive tyre waste was pyrolysed in a 200 cm³ static batch reactor in a N₂ atmosphere. The compositions and properties of the derived gases, pyrolytic oils and solid char were determined in relation to pyrolysis temperatures up to 720 °C and at heating rates between 5 and 80 °C min⁻¹. As the pyrolysis temperature was increased the percentage mass of solid char decreased, while gas and oil products increased until 600 °C after which there was a minimal change to product yield, the scrap tyres producing approximately 55% oil, 10% gas and 35% char. There was a small effect of heating rate on the product yield. The gases were identified as H₂, CO, CO₂, C₄H₆, CH₄ and C₂H₆, with lower concentrations of other hydrocarbon gases. Chemical class composition analysis by liquid chromatography showed that an increase in temperature produced a decrease in the proportion of aliphatic fractions and an increase in aromatic fractions for each heating rate. The molecular mass range of the oils, as determined by size exclusion chromatography, was up to 1600 mass units with a peak in the 300–400 range. There was an increase in molecular mass range as the pyrolysis temperature was increased. FT-i.r. analysis of the oils indicated the presence of alkanes, alkenes, ketones or aldehydes, aromatic, polyaromatic and substituted aromatic groups. Surface area determination of the solid chars showed a significant increase with increasing pyrolysis temperature and heating rate.     

溶剂油萃取深度脱芳烃实验

随着环保要求的日益严格和清洁燃料的需求增加,低芳烃含量溶剂油亦需进一步脱芳烃。液液萃取脱芳技术因具有操作条件缓和、萃取剂可循环利用、可得到芳烃副产品等优势被广泛应用,但针对低芳烃含量的原料,萃取剂的研发是关键问题。本实验采用N,N-二甲基甲酰胺（DMF）+乙二醇复合萃取剂萃取分离低浓度芳烃溶剂油体系,从萃取剂对甲苯的选择性系数（S）和分配系数（K）两方面出发优化了脱芳萃取剂配方,确定乙二醇质量分数为15%的复合萃取剂适用于萃取分离芳烃质量分数小于15%的低芳烃原料。测定了常压、40℃时 DMF-甲苯-正庚烷和复合萃取剂-甲苯-正庚烷体系的液液相平衡数据,并用Othmer-Tobias 方程对实验数据进行关联。相平衡数据证实了复合萃取剂更适用于低芳烃原料油脱芳。将优化的复合萃取剂用于溶剂油脱芳烃,实验结果表明在萃取温度40℃、萃取时间5min、分相时间10min、单级剂油质量比0.5的操作条件下,经7级错流萃取,溶剂油的芳烃质量分数可从9.15%降至0.76%,具有一定的工业应用前景。     

Essential Oil Yield and Composition Reflect Browsing Damage of Junipers

The impact of browsing on vegetation depends on the relative density and species composition of browsers. Herbivore density and plant damage can be either site-specific or change seasonally and spatially. For juniper (Juniperus communis) forests of a sand dune region in Hungary, it has been assumed that plant damage investigated at different temporal and spatial scales would reflect selective herbivory. The level of juniper damage was tested for a possible correlation with the concentration of plant secondary metabolites (PSMs) in plants and seasonal changes in browsing pressure. Heavily browsed and nonbrowsed junipers were also assumed to differ in their chemical composition, and the spatial distribution of browsing damage within each forest was analyzed to reveal the main browser. Long-term differences in local browsing pressure were also expected and would be reflected in site-specific age distributions of distant juniper populations. The concentrations of PSMs (essential oils) varied significantly among junipers and seasons. Heavily browsed shrubs contained the lowest oil yield; essential oils were highest in shrubs bearing no damage, indicating that PSMs might contribute to reduce browsing in undamaged shrubs. There was a seasonal fluctuation in the yield of essential oil that was lower in the summer period than in other seasons. Gas chromatography (GC) revealed differences in some essential oil components, suggesting that certain chemicals could have contributed to reduced consumption. The consequential long-term changes were reflected in differences in age distribution between distant juniper forests. These results confirm that both the concentration of PSMs and specific compounds of the essential oil may play a role in selective browsing damage by local herbivores.     

利用GC-MS与NMR技术研究干馏终温对桦甸页岩油组成性质的影响

通过控制桦甸油页岩干馏终温,得到5个不同终温下页岩油样品,对各页岩油样按沸点300℃进行切割,其中轻质油馏分(<300℃)进行GC-MS检测,对产物分类统计,分析页岩油组成成分随干馏终温变化规律;重质油馏分(>300℃)进行了¹H和¹³C核磁共振波谱分析,对谱图积分获得其氢、碳分布情况,研究了干馏终温对页岩油化学结构的影响。结果显示,轻质油组成中脂肪族化合物占绝大部分,其中正构烷烃、α-烯烃和正构醛、醇三者具有同源性,均由烷基自由基生成。随着干馏终温的升高,长链烷烃分解,支链烷烃侧链断裂,使轻质油脂肪烃碳链长度变短,重质油直链脂肪烃增多,页岩油发生更多的芳环缩合反应导致轻质油与重质油芳香环数量均增多,同时轻质油中芳环缩合程度加深。     

Microwave-heated pyrolysis of waste automotive engine oil: Influence of operation parameters on the yield,composition, and fuel properties of pyrolysis oil

The pyrolysis of waste automotive engine oil was investigated using microwave energy as the heat source, and the yield and characteristics of the pyrolysis oils (i.e. elemental analysis, hydrocarbon composition, and potential fuel properties) are presented and discussed. The microwave-heated pyrolysis generated an 88 wt.% yield of condensable pyrolysis oil with fuel properties (e.g. density, calorific value) comparable to traditional liquid transportation fuels derived from fossil fuel. Examination of the composition of the oils showed the formation of light aliphatic and aromatic hydrocarbons that could also be used as a chemical feedstock. The oil product showed significantly high recovery (90%) of the energy present in the waste oil, and is also relatively contaminant free with low levels of sulphur, oxygen, and toxic PAH compounds. The high yield of pyrolysis oil can be attributed to the unique heating mode and chemical environment present during microwave-heated pyrolysis. This study extends existing findings on the effects of pyrolysis process conditions on the overall yield and formation of the recovered oils, by demonstrating that feed injection rate, flow rate of purge-gas, and heating source influence the concentration and the molecular nature of the different hydrocarbons formed in the pyrolysis oils. The microwave-heated pyrolysis can be performed in a continuous operation, and the apparatus described which is fitted with magnetrons capable of delivering 5 kW of microwave power is capable of treating waste oil at a feed rate of 5 kg/h with a positive energy ratio of 8 (energy content of hydrocarbon products/electrical energy supplied for microwave heating) and a net energy output of 179,390 kJ/h. Our results indicate that microwave-heated pyrolysis shows exceptional promise as a means for recycling and treating problematic waste oil.     

糠醛抽出油制取橡胶填充油的研究

为了研制符合一定标准的橡胶填充油,以糠醛为溶剂对大庆石化减二线糠醛抽出油进行再抽提。本研究采用单级抽提方法进行了一系列条件实验,考察研制橡胶填充油的应用可行性。主要考察了抽提温度和剂油比对橡胶填充油的质量和收率的影响。研究结果表明：当剂油比一定时,随着温度的升高,产品收率上升,芳香烃含量下降;当温度一定时,随着剂油比增大,产品收率先上升后下降,芳香烃含量先上升后下降。综合考虑产品的质量和收率,本实验范围内较适宜的操作条件为：抽提温度60℃,质量剂油比2.0。在此条件下,产品收率为52.3%,芳香烃组分的含量为80.6%,符合某些企业橡胶填充油的使用标准。     

Electric conductivity test for quality assessment of aromatic and medicinal plants after drying

For the production of essential oils and aromatics to be possible throughout the year, it is necessary to continuously supply the plant raw material to the industry or store the plant material for a designated time. However, to allow the plant material to remain in storage with a high quality, it is essential to reduce its water content by drying. This has motivated the oil extraction industries to demand a better yield and quality from the drying process and raw materials, necessitating fast and efficient evaluation parameters. Thus, the aim of this study was to develop an electric conductivity test for evaluating the quality of aromatic and medicinal plants and to quantify the essential oil yield of the dry vegetable material. The drying experiments were conducted at different temperatures and air velocities by altering the control of the drying conditions. Various aromatic plants with different plant mass, volume of deionized water, and temperature of the vegetal material were examined by the electric conductivity test. The qualities of the fresh and dry plants were compared through these tests and yields of essential oil. Increase in the drying air temperature influenced the increase in the dehydration rate of the aromatic and medicinal plants. Higher drying temperatures decreased the physical quality as evaluated by the electric conductivity test and essential oil yield of the aromatic and medicinal plants. The parameters for validation of the electric conductivity test methodology in aromatic and medicinal plants were defined as an exposure time of 33?h, 5?g of fresh plant material in 75?mL of deionized water, 1?g of dry plant material in 50?mL of deionized water, and temperature of 25°C. The electric conductivity test was demonstrated as an appropriate method to be used in the quality control of aromatic plants in essential oil extraction industries. The use of the electric conductivity test will enable the oil extraction industry to monitor the yield and quality of the essential oils extracted from the aromatic plants after drying and storage.     

Mechanism of high-pressure hydrogenolysis of Hokkaido coals (Japan) 3. Chemical structure changes in coal asphaltenes during hydrogenolysis

Asphaltenes produced by hydrogenolysis of coal were further hydrogenated in a batch autoclave at 400°C and 22 MPa hydrogen pressure. Red-mud was used as a catalyst and sulfur as promoter. The hydrogen content of the residual asphaltene increases and the fraction of aromatic carbon and the fraction of protons bound to aromatic carbons decrease as the reaction proceeds, indicating that hydrogenation of aromatic rings occurs. Aromatic ring systems of more than 2 rings are relatively easily hydrogenated to 2 rings. However, 2 ring systems are not easily hydrogenated. The heteroatoms-to-carbon ratios are similar for both the oil and the residual asphaltene, but less than that of the original asphaltene. The main differences in the chemical structure between the oil and the residual asphaltene are the hydrogen-to-carbon ratio, the fraction of aromatic carbon, the molecular weights and the average degrees of crosslinking. The residual asphaltene is composed of trimers and/or oligomers of unit structures of two or more condensed aromatic rings bound together by crosslinks. The size and composition of the condensed ring systems varies about the average properties measured in these experiments. Cleavage of the crosslinks by hydrogenation and heteroatom removal produces oil, composed for the most part of monomers of unit structures of two condensed aromatic rings. Coals of different rank show similar behavior although the magnitude of the changes depends on rank.     

Condensation Reactions of Softwood and Hardwood Lignin Model Compounds Under Organic Acid Cooking Conditions

In order to examine the condensation reactions of softwood and hardwood lignin during organic acid cooking, mixtures of benzyl alcohol type lignin model compounds with guaiacyl and syringyl units as the sources of benzyl cations and creosol and 5-methoxycreosol as the sources of electron-rich aromatic carbons were cooked under acidic pulping conditions.

From the yield of the condensation products in the initial reactions, it was shown that the carbonium cations of guaiacyl nuclei were more reactive than those of syringyl nuclei.

Syringyl type aromatic ring carbons had higher reactivities than guaiacyl type ones.

The cleavage of the benzyl ether bond in syringyl compounds was slower than that of guaiacyl compounds.

The diphenylmethane structures formed by the condensation reaction between veratryl alcohol and 5-methoxycreosol were found to be unstable under the strong acidic cooking conditions.

It is concluded that the condensation reactions between benzylic cations from the guaiacyl compounds and the electron rich aromatic ring carbons of syringyl ones are very fast, but the condensation products are unstable under the strong acidic pulping conditions.

When the guaiacyl nuclei react as an electron-rich aromatic carbon, the reaction is slower but the condensation product is much more stable.

These differences in reactivities, and the stabilities of the condensation products, may contribute to the resistance of softwood toward complete delignification on acid pulping.     

Distribution of polynuclear aromatic ring classes in the alberta basin bitumens and crude oils

The total polynuclear aromatic hydrocarbon (PAH) content and relative distribution of the fused aromatic ring classes have been studied in four Cretaceous bitumens and crude oils of varying degree of geothermal maturation. A high performance liquid Chromatographic (HPLC) separation, selective for up to four fused aromatic rings, was used to separate the PAH ring systems. The effect of geothermal maturation was simulated by reductive treatment of the heavy Athabasca bitumen. The treatment produced PAH ring distribution similar to that in the light Medicine River oil, and diminished PAH content considerably. The 3- and 4-fused ring systems increased while hydrocarbons containing more than four fused rings decreased. Alkyl substitution was also reduced as a result of both the natural and simulated maturations. Separation efficiency was monitored by refractive index and u.v. detectors, g.c., m.s., ¹³C n.m.r. and spectrofluorometry.     

松香裂解油的化学组成与性能分析

以活性白土为催化剂对松香进行催化裂解正交试验,并对裂解产物的化学组成及理化性能指标进行分析测试。结果表明:活性白土可以在较低的反应温度和较短的反应时间内对松香起到催化裂解作用,最佳工艺条件为:反应温度240℃,反应时间1.5 h,催化剂用量为松香质量的10%。裂解油酸值稳定在0.69～0.75 mg/g,得率稳定在60%～63%。气相色谱-质谱(GC-MS)分析表明,得到的非挥发性裂解油主要由苯、萘、酮、酯和菲等化合物组成,松香裂解油酸度为0.075 g/L,运动黏度(20℃)为47.6 mm²/s,冷凝点为-30℃,冷滤点为11℃,十六烷值为30.4。松香裂解油经过复配和性能改良,可达到石化柴油国家标准。