Biofuels from waste fish oil pyrolysis: Chemical composition

In a previous study, waste fish oil was converted into bio-oil by a fast pyrolysis process at 525 °C in a continuous pilot plant reactor with 72-73% yield. The bio-oil was distilled to obtain light bio-oil and heavy bio-oil and these biofuels were characterized in terms of their physico-chemical properties. In this study, the chemical composition of light bio-oil and heavy bio-oil was determined using GC-FID, GC-MS, ¹H and ¹³C NMR techniques. The GC-MS analysis of waste fish oil showed the main composition of fatty acids to be the following: C_16:0 (15.87%), C_18:2 (20.96%), C_18:1 (17.29%), C_20:5 (5.11%), C_20:1 (7.59%), C_22:6 (4.53%), C_22:1 (10.42%) and others. The GC-FID analysis of the light bio-oil showed 482 compounds that were PIONA classified as paraffins (4.48%), iso-paraffins (8.31%), olefins (26.56%), naphthenes (6.07%) and aromatics (16.86%). The heavy bio-oil had a similar chromatographic profile as diesel oil, with a high content of carboxylic acids and olefins. These results are in good agreement with those for the gasoline and diesel oil fractions of petroleum.     

Steam pyrolysis of an industrial waste for bio-oil production

Potato skin, a food industry waste, was pyrolysed under three different atmospheres namely static, nitrogen, and steam to produce bio-oil and its derivatives. The oil yield obtained at 550 °C was 24.77% in static atmosphere, whereas it reached to 27.11% in nitrogen atmosphere. Moreover, the use of steam caused a sharp increase of oil yields up to 41.09% with a steam velocity of 1.3 cm s^− 1. TG-DTA analyses were applied on the raw material to investigate the thermal degradation. Liquid products obtained under the most suitable conditions were characterized by elemental analyses, FT-IR and ¹H NMR. In addition, column chromatography was employed to separate the bio-oil into its derivatives. Asphaltene fraction of bio-oil is decreased under steam atmosphere. Gas chromatography was also used to investigate the C distributions. The characterization has shown that the bio-oil obtained under steam atmosphere was more beneficial than those obtained under both static and inert atmospheres. Further comparison of H/C ratios of pyrolysis oils with conventional fuels indicates that the H/C ratios of the oils obtained in this study lie between those of light and heavy petroleum products. It can be concluded that potato skin could be evaluated as a promising biomass candidate of bio-oil production.     

Bio-oil derived from empty fruit bunches

The fast pyrolysis of washed and unwashed empty fruit bunches (EFB), a waste of the palm oil industry, is investigated in this study. Firstly, the composition and particle size distribution of the washed and unwashed feedstock were determined and the thermal degradation behaviour was analysed by TGA. Then a 150 g/h fluidised bed bench scale fast pyrolysis unit was used to study the impact of key variables: reactor temperature in the range 425-550 °C and feedstock ash content in the range 1.03-5.43 mf wt%. The properties of the liquid product were analysed and compared with wood derived bio-oil and petroleum fuels. It was found that the maximum ash content of washed feedstock that still yields homogenous liquids is less than about 3 mf wt%. The experiments also indicated that the fast pyrolysis of washed EFB with a low ash content gave similar yields as commonly obtained for wood.     

Synthetic fuel production from tea waste: Characterisation of bio-oil and bio-char

The pyrolysis of tea waste was studied for determining the main characteristics and quantities of liquid and solid products. Particular investigated process variables were temperature (673-973 K), heating rate (5-700 K min⁻¹) and nitrogen gas flow rate (200-800 cm³ min⁻¹). The maximum oil and char yields are 30.4 (773 K) and 43.3% (673 K), respectively. The liquid and its aliphatic sub-fraction were characterized by elemental analysis, FT-IR, ¹H NMR, and GC/MS. The char was characterized with elemental analysis, SEM, BET, and FT-IR techniques. The aliphatic sub-fraction of the obtained bio-oil contains predominantly n-alkanes and alkenes, and branched hydrocarbons. According to the experimental results the liquid products can be used as liquid fuels, whereas the solid product seems to be not suitable for adsorption purposes, due to having low surface areas.     

Application of the Shvo catalyst in homogeneous hydrogenation of bio-oil obtained from pyrolysis of white poplar: New mild upgrading conditions

Upgrading of bio-oils obtained from the fast pyrolysis of biomasses requires the development of efficient catalysts able to work under mild conditions and to cope with the complex chemical nature of the reactant. The present work focuses on the use of the ruthenium based Shvo homogeneous catalyst for the hydrogenation of model mixtures (vanillin, cinnamaldehyde, methylacetophenone, glycolaldehyde, acetol, acetic acid) and of a real bio-oil. The hydrogenation of model compounds has been investigated both in mono- and biphasic mixtures under a P(H₂) = 10 atm in the temperature range of 90-145 °C varying the substrate to catalyst molar ratio from 2000:1 to 200:1. Employing the most active reaction conditions (substrate/catalyst 200:1, T = 145 °C, P(H₂) = 10 atm) the Shvo catalyst maintains its performances under acidic “bio-oil conditions” leading to the almost quantitative conversion of the polar double bonds within 1 h. The activity of the Shvo catalyst was also investigated for the hydrogenation of a bio-oil from poplar in solvent free conditions. Hydrogenation deeply changed the chemical nature of the pyrolysis oil. Aldehydes, ketones and non-aromatic double bonds were almost totally hydrogenated. The catalytic system also promoted the hydrolysis of sugar oligomers into monomers.     

Biorefineries in Kraft pulp mills for biofuels production: A critical review

Kraft pulp production generates residues and by-products of significant importance to the mill. Solid residues from forestry activities are commonly used to generate steam in power boilers. In the recovery cycle, black liquor generates steam (and subsequently energy) by burning in the Tomlinson boiler, while white liquor is regenerated. Well-developed alternative technologies can use these residues and by-products to generate different types of biofuels. This review addresses the use of such technologies integrated with Kraft mills, in the concept of biorefineries, showing advantages, disadvantages, and successful examples. Solid residues from forestry can be used to produce bio-oil through processes such as fast pyrolysis and hydrothermal liquefaction. Bio-oils are currently used for heating through combustion in commercial/industrial boilers, but greater appreciation occurs if used as biofuels, which is done through catalytic upgrading processes. Black liquor gasification generates synthesis gas, which can be burned for energy co-generation, used to produce synthetic fuels, or as a hydrogenating agent for bio-oil or crude tall oil catalytic upgrading. Kraft biorefineries are gradually being implemented, justifying efforts to improve existing and new biomass conversion technologies.     

Influence of temperature and alumina catalyst on pyrolysis of corncob

Corncob has been investigated as an alternative feedstock to obtain fuels and chemicals via pyrolysis in fixed-bed reactor. The influence of pyrolysis temperature in the range 300-800 °C as well as the catalyst effects on the products was investigated in detail and the obtained results were compared. The results indicated that a maximum oil yield of 22.2% was obtained at a moderate temperature of 600 °C. The oil yield was reduced when the temperature was increased from 600 to 800 °C, whereas the gas yield increased.Pyrolysis oils were examined by using instrumental analysis, ¹H NMR spectroscopy and GC/MS. This analysis revealed that the pyrolysis oils were chemically very heterogeneous at all temperatures. It was determined that the most abundant compounds composing the bio-oil were phenolics.It was observed that the catalyst decreased the reaction temperature. Most of the components obtained using a catalyst at moderate temperatures was close to those obtained at high temperatures without using a catalyst. Moreover, the use of a catalyst and the high temperatures of the reactions also decreased the amount of oxygenated compounds produced.According to these results, corncob bio-oils can be used as fuel and constitute a valuable source of chemical raw materials.     

生物质能源转化技术与应用(Ⅲ)——生物质热解液体燃料油制备和精制技术

生物质能源是唯一可再生、可替代化石能源转化成气态、液态和固态燃料以及其它化工原料或者产品的碳资源。随着化石资源的枯竭和人类对全球性环境问题的关注,生物质能源替代化石能源利用的研究和开发,已成为国内外众多学者研究和关注的热点。本系列讲座主要讲述以生物质资源为主要原料,通过不同途径转化为洁净的、高品位的气体、液体或固体燃料。本讲主要综述了生物质高压液化、快速热解液化制备液体燃料油技术现状、工艺及设备,并在总结生物质热解液体燃料油特性的基础上,总结了生物热解液体燃料油的物理法精制技术(包括脱水、添加溶剂和乳化)和化学法精制技术(包括催化加氢、催化裂解、催化酯化、水蒸气重整)的研究现状,并对其精制机理、优缺点进行了分析。随着制备和精制技术的深入研究,生物质热解液体燃料油可望替代汽油、柴油等化石燃料而越来越受到人们的关注。     

生物质油加氢脱氧精制研究进展

随着石油能源渐趋匮乏,生物质高温裂解制备生物质油备受关注。而生物质油中氧含量高达40%,这将影响生物质油的稳定性、极性、热值、粘度和酸性等,应必须对其进行加氢脱氧精制处理。文中介绍了裂解生物质油的组成分布和特点,阐述了裂解生物质油加氢脱氧精制的反应过程和影响因素。     

浒苔热裂解制取生物油的试验

为了解决化石燃料短缺以及沿海浒苔过度繁殖所带来的问题,提出将浒苔做原料通过直接热裂解的方法转化为生物油。本文在实验室组装的反应器内系统地考察了温度、时间以及原料粒径对产物收率以及产物分布的影响。实验结果表明:实验原料的粒径越小,其生物油的产率越高;当反应温度为350℃,反应时间为40min,原料粒径为60目的最优条件下,生物油的产率高达30.5%,不凝气产率可达13.9%。对产物进行分析发现:生物油主要包含醛、酮、酚类以及醇、羧基酸、酯类等化合物;不凝气主要由CO2、CO、CH4以及C2～C5的小分子烃类组成。     

Steam gasification reactivity of char from rapid pyrolysis of bio-oil/char slurry

A slurry of bio-oil and char originating from wood pyrolysis is a promising gasifier feed-stock because of its high energy density. When such a slurry is injected into a high temperature gasifier it undergoes a rapid pyrolysis yielding a char which then reacts with steam. The char produced by pyrolysis of an 80 wt% bio-oil/20 wt% char mixture at heating rates of 100-10,000 °C/s was subjected to steam gasification in a thermogravimetric analyzer. The original wood char from the bio-oil production was also tested. Gasification was conducted with 10-50 mol% steam at temperatures from 800 to 1200 °C. Reactivity of the slurry chars increased with pyrolysis heating rate, but was lower than that of the original chars. Kinetic parameters were established for a power-law rate model of the steam-char reaction, and compared to values from the literature. At temperatures over 1000 °C, the gasification rates appeared to be affected by diffusional resistance.     

生物油气化技术的研究进展

概述了国内外关于生物油水蒸气重整、裂解气化和超临界水气化以及其模型化合物气化和生物油气化制备合成气的净化等技术的研究进展,指出无论从经济方面还是技术方面,生物质热解油气化制备合成气都优于生物质直接气化制备合成气,但目前这一技术还处于实验室研究阶段。     

Pyrolysis characteristics of Oriental white oak: Kinetic study and fast pyrolysis in a fluidized bed with an improved reaction system

The kinetic parameters for the pyrolysis of Oriental white oak were evaluated by thermogravimetric analysis (TGA). The white oak was pyrolyzed in a fluidized bed reactor with a two-staged char separation system under a variety of operating conditions. The influence of the pyrolysis conditions on the chemical and physical characteristics of the bio-oil was also examined. TGA showed that the Oriental white oak decomposed at temperatures ranging from 250 to 400 °C. The apparent activation energy ranged from 160 to 777 kJ mol^− 1. The optimal pyrolysis temperature for the production of bio-oil in the fluidized bed unit was between 400 and 450 °C. A much smaller and larger feed size adversely affected the production of bio-oil. A higher fluidizing gas flow and higher biomass feeding rate were more effective in the production of bio-oil but the above flow rates did not affect the bio-oil yields significantly. Recycling a part of the product gas as a fluidizing medium resulted the highest bio-oil yield of 60 wt.%. In addition, high-quality bio-oil with a low solid content was produced using a hot filter as well as a cyclone. With exception of the pyrolysis temperature, the other pyrolysis conditions did not significantly affect the chemical and physical characteristics of the resulting bio-oil.     

Effects of particle size on the fast pyrolysis of oil mallee woody biomass

This study aims to investigate the effects of biomass particle size (0.18-5.6 mm) on the yield and composition of bio-oil from the pyrolysis of Australian oil mallee woody biomass in a fluidised-bed reactor at 500 °C. The yield of bio-oil decreased as the average biomass particle size was increased from 0.3 to about 1.5 mm. Further increases in biomass particle size did not result in any further decreases in the bio-oil yield. These results are mainly due to the impact of particle size in the production of lignin-derived compounds. Possible inter-particle interactions between bio-oil vapour and char particles or homogeneous reactions in vapour phases were not responsible for the decreases in the bio-oil yield. The bio-oil samples were characterised with thermogravimetric analysis, UV-fluorescence spectroscopy, Karl-Fischer titration as well as precipitation in cold water. It was found that the yields of light bio-oil fractions increased and those of heavy bio-oil fractions decreased with increasing biomass particle size. The formation of pyrolytic water at low temperatures (<500 °C) is not greatly affected by temperature or particle size. It is believed that decreased heating rates experienced by large particles are a major factor responsible for the lower bio-oil yields from large particles and for the changes in the overall composition of resulting oils. Changes in biomass cell structure during grinding may also influence the yield and composition of bio-oil.     

生物质热解制生物油及其提质研究现状

生物质能源作为可再生能源的重要组成部分,其综合高效利用在能源替代与补充、保护生态环境等方面具有重要的战略意义。生物油是生物质通过热裂解技术获得的液体产物,具有能量密度较高、环境友好、可再生及可直接输送等优点,可替代传统化石燃料推广使用,解决日益严重的能源紧缺与环境污染等问题。生物质热解制油技术的开发与利用,已成为新世纪可持续能源研究领域的重要课题之一。总结了近年来生物质热解制油技术的主要研究进展,重点关注热解反应器、催化热解技术与生物油的提质利用方面的研究,介绍了碱金属、氧化物和分子筛3种生物质热解催化剂,以及乳化、催化加氢、催化裂解、催化酯化和重整制氢5种生物质提质方法,最后对生物质热解技术的现状及发展趋势进行了总结和概括。     

水合CaO对微拟球藻催化热解制备生物油的影响

以水合CaO为催化剂,在管式炉内研究了微拟球藻的催化热解.考察了催化剂用量对微拟球藻热解产物及油品组成的影响,并通过直接再生和强化再生研究了催化剂的再生特性.结果表明:随着水合CaO用量逐渐加大,生物油性能明显改善.在催化剂/藻质量比为1:3时催化热解得到的生物油产率为28.5%,具有含氧量低、热值高、运动黏度低、含水率低等优点.与直接热解油相比,催化热解油中羧基化合物和羟基化合物含量均有明显下降,而脂肪烃和芳香烃含量均显著增加.第1次和第2次循环再生实验中,直接再生催化剂依然具有较高的催化活性.通过在直接再生过程中引入水洗强化步骤,可对再生催化剂表面进行更新,并降低其表面的碱金属含量,明显改善再生催化剂所催化热解的油品质量,提高再生催化剂活性.     

矿物质对生物质热解的影响及其解决方案

通过对一年生和多年生的生物质及其热解油组成的分析,探讨了影响生物质热解油组成及其酸度的重要因素是生物质中的金属盐矿物质,金属盐舍量增加,致使热解油收率降低、酸含量增加。对现有的生物质热解工艺进行了比较和评述,提出了消除金属矿物质影响和含酸少的新型生物质热解工艺。     

Pyrolysis kinetics and combustion characteristics of waste recovered fuels

Alternative fuels, such as biomass and refuse derived fuels tend to play an increasingly important role in the European energy industry. Co-firing fuels derived from non-hazardous waste streams have the potential of covering a significant part of the future demand on co-incineration capacities, which is expected to increase due to the implementation of the 2000/76 EC landfill Directive. However, their combustion behaviour has not yet been fully investigated, because of the difficulty to define representative fuel characteristics simulating accurately all the fuel fractions. In the present study, refuse derived fuel behaviour was investigated by thermogravimetry under pyrolysis and combustion conditions. A non-isothermal thermogravimetric analyser (TA Q600) operated at ambient pressure was used for both the pyrolysis and combustion experiments. The devolatilisation of the waste samples was investigated at a temperature range of 30-1000 °C with the constant heating rate of 20 °C/min and for particle sizes between 150 and 250 μm. Combustion tests were realized under the same heating conditions. The independent parallel, first order, reactions model was elaborated for the kinetic analysis of the pyrolysis results. The thermal degradation of the refuse derived fuel samples was modeled assuming four parallel reactions corresponding to the devolatilisation of cellulose, hemicellulose, lignin and plastics. Increased activation energies were calculated for the plastics fraction. Lignin presented the lowest contribution in the pyrolysis of the samples. Slightly increased combustion reactivities were found for the waste fuel samples compared to lignite. It is concluded that waste recovered fuels can be used in existing combustion facilities either alone or in combination with coal and future investigations should focus on the operational behaviour of large-scale facilities when exploiting these waste species.     

Effect of crystallization temperature on the in situ valorization of physic nut (Jatropha curcus L.) wastes using synthetic HZSM-5 catalyst

Physic nut waste is selected as the biomass feedstock for fast pyrolysis as it is available in large amounts from biodiesel production in Thailand. The volatile matter and fixed carbon contents are 73.8% and 13.6% while ash contents are 5.8%. Carbon is the main element with 49.03 wt%. The oxygen content of 39.0 wt% is considerably high which could directly convert to the oxygenated pyrolysis liquid products. To decrease oxygenated compounds, HZSM-5 was used as a catalyst to upgrade pyrolytic products from fast pyrolysis using analytical pyrolysis–GC/MS method. The HZSM-5 catalyst was successfully synthesized by hydrothermal method at 160–180 °C for 24 h. The particle size, surface area, and pore diameter were 11.25–15.52 μm, 567–582 m²/g, and 21.78–26.11 Å, respectively. The pyrolysis was performed at 500 °C with the Jatropha wastes to catalyst ratio of 1:1–1:10. The presence of HZSM-5 contributed to eliminate the undesirable oxygenated compounds such as acids and ketones which could alleviate problem regarding acidity and instability in bio-oil. In addition, it enhanced significantly the yields of desirable hydrocarbon compounds. The increase in catalyst contents had an effect on the enhancement of hydrocarbons yields, and tended to promote deoxygenation and denitrogenation. At moderate biomass to catalyst ratio (1:5), HZSM-5 synthesized at 170 °C contributed to improve the hydrocarbon yields of 95%, including mainly toluene and xylene, which are valuable products because of their high heating value properties.     

Combustion of bio-oil ethanol blends at elevated pressure

This paper reports an investigation on the combustion performance of bio-oil/ethanol blends. Experiments were conducted in a constant volume vessel operating at a pressure of 25 bar and temperature 1100 K. Bio-oil produced via the fast pyrolysis of a spruce feedstock was blended to ethanol to form three stable blends containing 10%, 20% and 40% bio-oil by weight. In addition, ethanol and standard automotive grade diesel were tested as reference fuels. Measured vessel pressure was used in a single-zone heat release analysis, while two-colour optical pyrometry was used to investigate particle loading and temperature. Results show that for similar injections of fuel energy, use of up to 20% bio-oil in ethanol has limited impact on the performance of ethanol while 40% bio-oil in ethanol produced instability in the pressure trace near the end of the combustion process. Burning rates are similar for blends and ethanol. Addition of bio-oil to ethanol was found to increase combustion generated particle load, and this increased with bio-oil concentration, but remained much lower than particle concentration in diesel. Addition of bio-oil also resulted in formation of char particles that appear as luminous clusters outside the boundary of the spray. This suggests these particles will cool rather than oxidize. The presence of unburnt char particles in large numbers may have consequences for bio-oil as an alternative diesel fuel.