The Evaluation of Mesoporous Materials as Catalyst in Fast Pyrolysis of Wheat Straw

In this study, wheat straw was chosen as a biomass sample and the fast pyrolysis of this sample was carried out with or without catalyst at different conditions in a well-swept fixed-bed reactor. Experiments were carried out in a well-swept tubular fixed-bed reactor with a heating rate of 300°C/min, between pyrolysis temperature ranges 300–800°C in the nitrogen atmosphere. The results indicated that a maximum oil yield of 31.9% was obtained at a pyrolysis temperature of 500°C in non-catalytic procedure. Siliceous and Al-MCM-41 materials were evaluated as potential catalysts in the pyrolysis experiments. Mesoporous materials have large pore dimensions with strong acid sites. These acidic sites catalyze some reactions in pyrolysis. The product yields and the quality of bio-oil were influenced with using MCM-41 materials. The bio-oil yield was reduced, whereas the gas yield increased with using a catalyst in the experiments. An increase in the fractions of pure phenol, alkyl phenols, alkenes+alkanes, carbonyls, aromatic, and cyclic compounds and a decrease in the fractions of methoxy phenols, acids+esters, furans, and alcohols were observed in the presence of Al-MCM-41 material. According to all results, the use of Al-MCM-41 materials as catalyst in the pyrolysis can be suggested to obtain both quality fuels and valuable chemicals.     

溶剂型聚氨酯涂料废物热解特性及动力学研究

采用TG研究溶剂型聚氨酯涂料废物在不同升温速率、N2气氛影响下的热解特性规律。升温速率取5,10,20,30℃/min;气氛取N2气氛(50 m L/min);实验温度范围为20~800℃。研究表明,随着升温速率的增大,涂料废物热解反应各阶段起始温度、终止温度、最大失重速率温度均向高温方向移动。在500℃时,涂料废物的热分解已基本完成。运用Kissinger法和Flynn-Wall-Ozawa法进行热解动力学分析,得到溶剂型聚氨酯涂料废物热解阶段的表观活化能为196.053 3 kJ/mol。     

Preparation of jet engine range fuel from biomass pyrolysis oil through hydrogenation and its comparison with aviation kerosene

The Bio-oil was produced from the pyrolysis of agricultural wastes (Eucalyptus sawdust) and discarded soybean frying oil. The temperature of the pyrolysis system was initiated at 28°C and increased to 850°C. Atmospheric distillation of crude bio-oil was performed and a fraction at a temperature range 160–240°C (pyrolysis oil) was separated and subjected to GC-MS, ¹H-NMR, TGA and FTIR analysis to identify the different properties and compounds present in pyrolysis oil. It was noticed that there was an abundance of oxygen and nitrogen containing compounds as well as other reactive species in pyrolysis oil. To reduce the amount of these species, the pyrolysis oil was subjected to hydrogenation in the presence of NiMo as a catalyst. After hydrogenation, the atmospheric distillation of hydrogenated bio-oil was performed and another fraction at temperature range 160–240°C (hydrogenated bio-oil) was separated and analyzed by the same techniques. It was noticed that during hydrogenation, more than 60% oxygenated and other reactive species were converted into hydrocarbons. Hydrogenated bio-oil showed very similar physico-chemical properties such as distillation curve, density, viscosity, freezing point, flash point, the presence of hydrocarbons and enthalpy of combustion as aviation kerosene also known as QAV-1.     

Pyrolysis of cellulose under catalysis of SAPO-34, ZSM-5, and Y zeolite via the Py-GC/MS method

Bio-oil from pyrolysis of biomass is an important renewable source for liquid fuel and/or for chemicals. However, the application of bio-oil was severely restricted due to its high viscosity, acidity, and low heating value. Hence, it is necessary to upgrade the bio-oil for deoxygenation or for chemicals by catalytic reactions. In this paper, the catalytic behaviors of SAPO-34, ZSM-5, and Y zeolite on pyrolysis of cellulose were investigated via pyrolyzer combined with gas chromatography and mass spectrometer (Py-GC/MS) method in Py-mode. The results showed that ZSM-5 and Y zeolite could promote the conversions of oxygen-containing components to gases, water, aromatics, and phenols. Comparatively, more gas and water were generated under the catalysis of Y zeolite at lower temperatures, while at temperatures above 700°C, the effect of ZSM-5 became more distinct; aromatics were more generated under the catalysis of ZSM-5, while Y zeolite exerted a more distinct role in promoting the formation of phenols. The effect of SAPO-34 caused more water and furfural derivatives, less aromatics and phenols, and exerted a weak influence on gases.     

Co-pyrolysis of paper waste and mustard press cake in a semi-batch pyrolyzer—optimization and bio-oil characterization

Under the present research study, the co-pyrolysis of paper waste and mustard press cake was conducted in a 50 mm diameter and 640 mm long semi-batch pyrolyzer in the temperature range of 673 to 1173 K in nitrogen atmosphere and synergistic relationship between the pyrolysis of two feed stocks has been observed. The paper wastes were composed of local packing paper, newspaper-based food packets of grocery, and printing paper in the ratio of 6:3:1. During co-pyrolysis, response surface methodology (RSM) technique has been employed using Design Expert Version 7.0.0 to determine the collective effects of factors, namely, A: ratio of paper waste to mustard press cake and B: pyrolysis temperature, on the yield of bio-oil, energy yield, and oxygen content of bio-oil. Optimization has been done by using RSM to identify the individual sets of values of independent parameters corresponding to maximum bio-oil yield (A: 9.0:1, B: 874.75 K), energy yield (A: 8.80:1, B: 812 K), and minimum oxygen content of bio-oil (A: 2.75:1, B: 883.06 K). Bio-oil obtained at maximum energy yield condition has been characterized using the Gas chromatography–mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FTIR) spectroscopic analyses. The array of compounds present in the bio-oil compounds has been compared with literature data available on pyro-oil obtained from similar feed stocks.     

Pyrolysis of commingled waste textile fibers in a batch reactor: Analysis of the pyrolysis gases and solid product

The main object of this study was the investigation of the thermal recycling of commingled waste textile fibers, with the aim of the production of useful end products. Differential scanning calorimetry/Thermo gravimetric analysis (DSC/TGA) was applied to determine the thermal degradation characteristics of the commingled waste textile fibers and there are two peaks located at the temperature ranges of 299–360°C and 399–500°C. Commingled waste fiber was pyrolyzed in a nitrogen atmosphere in relation to three different temperatures (500, 600, and 700°C), heating rates (25 and 50°C min^?1), and retention times (15 and 30 min). The effect of the experimental conditions such as pyrolysis temperature, heating rates, and retention time on the formation of char and gas--liquid products was investigated and the product yields were determined from the rate of the weight loss. The highest conversion rate 82.9 wt.% liquid--gas product and 17.1 wt.% char product was achieved at 700°C. Pyrolysis gases were taken for every 7, 15, and 25 min and were analyzed for major components such as CO, CO₂, CH₄, and H₂ by gas chromatography. The pyrolysis char called as carbon black derived from the pyrolysis of commingled waste textile fibers was analyzed for a range of properties, including the elemental analysis, moisture content, ash content, calorific value, and trace metal analysis.     

Economic assessment of flash co-pyrolysis of short rotation coppice and biopolymer waste streams

The disposal problem associated with phytoextraction of farmland polluted with heavy metals by means of willow requires a biomass conversion technique which meets both ecological and economical needs. Combustion and gasification of willow require special and costly flue gas treatment to avoid re-emission of the metals in the atmosphere, whereas flash pyrolysis mainly results in the production of (almost) metal free bio-oil with a relatively high water content. Flash co-pyrolysis of biomass and waste of biopolymers synergistically improves the characteristics of the pyrolysis process: e.g. reduction of the water content of the bio-oil, more bio-oil and less char production and an increase of the HHV of the oil. This research paper investigates the economic consequences of the synergistic effects of flash co-pyrolysis of 1:1 w/w ratio blends of willow and different biopolymer waste streams via cost-benefit analysis and Monte Carlo simulations taking into account uncertainties. In all cases economic opportunities of flash co-pyrolysis of biomass with biopolymer waste are improved compared to flash pyrolysis of pure willow. Of all the biopolymers under investigation, polyhydroxybutyrate (PHB) is the most promising, followed by Eastar, Biopearls, potato starch, polylactic acid (PLA), corn starch and Solanyl in order of decreasing profits. Taking into account uncertainties, flash co-pyrolysis is expected to be cheaper than composting biopolymer waste streams, except for corn starch. If uncertainty increases, composting also becomes more interesting than flash co-pyrolysis for waste of Solanyl. If the investment expenditure is 15% higher in practice than estimated, the preference for flash co-pyrolysis compared to composting biopolymer waste becomes less clear. Only when the system of green current certificates is dismissed, composting clearly is a much cheaper processing technique for disposing of biopolymer waste.     

Yield and quality of charcoals from olive mill residues and its stone and pulp fractions: An enhanced comparative study

Pyrolysis is a promising way to upgrade large amounts of residues from olive oil processing into charcoal. Pyrolysis of the stone and pulp fractions needed to be investigated before conclusions could be drawn. We subjected the olive stone fraction, the pulp fraction, and a mixture of the two to dynamic pyrolysis and isothermal pyrolysis at 360°C. We characterized the charcoals resulting from isothermal pyrolysis at 360°C for different durations in terms of the fixed-carbon content (FCC), carbon content (CC), and high heating value (HHV). We found that charcoal yield from the pulp was higher than that from the stones, which were 38.1% and 32.9%, respectively, after pyrolysis for 360 min. This seemingly unexpected result was due to the high contents of ash (6.22%) and extractives (13%) in the pulp, which remained completely and partially undecomposed, respectively, in the charcoals and are accounted for when calculating yields. However, charcoals obtained from the stones were of higher quality than charcoals from the pulp, with lower ash content and higher FCC, CC, and HHV. In particular, the FCC, CC, and HHV after pyrolysis for 360 min were 73.2%, 74.4%, and 30.2 MJ/kg for the stones and only 61.8%, 63.2%, and 25.9 MJ/kg for the pulp, respectively. Depending on the required quality of the final charcoal, our results help decide whether to pyrolyse the entire olive residues or only one of the two fractions, more likely the stones.     

Upgrading of bio-oil from palm kernel shell by catalytic cracking in the presence of HZSM-5

Upgrading of bio-oil extracted from palm kernel shell (PKS) was performed using a lab-scale fixed-bed reactor with HZSM-5 as a catalyst. The catalytic cracking was carried out at optimized conditions: 0.3-MPa pressure, temperature of 500°C, and oil to catalyst ratio of 1:5. One of the challenges in upgrading bio-oil by catalytic cracking is deactivation of catalyst due to coke formation on catalyst surface. To overcome coke deposition, the upgrading process was carried out at 0.3-MPa pressure. Characterization of raw and upgraded bio-oil obtained through catalytic cracking was discussed in detail, indicating improvement in its physical properties. The distribution of products after cracking of bio-oil includes 58.89 wt% of organic liquid product, 15.63 wt% of aqueous fraction, 7.84 wt% of coke, and 17.64 wt% of gases. The degree of deoxygenation and calorific value of organic liquid product is 43.74% and 31.65 MJ/kg respectively. Organic liquid product obtained comprises 17.55% of hydrocarbons within the gasoline range. Hence, HZSM-5 proved its effectiveness for upgrading the bio-oil in a continuous mode.     

Conversion of leather wastes to useful products

The main objective of the present study is to investigate the production of useful materials from different kinds of leather waste. Three different types of tannery wastes (chromium- and vegetable-tanned shavings, and buffing dust) were pyrolyzed in a fixed bed reactor at temperatures of 450 and 600 °C under N₂ atmosphere. Gas, oil, ammonium carbonate and carboneous residue were obtained by pyrolysis. The effect of temperature and type of leather waste on product distribution of pyrolysis was investigated. Buffing dust gave the highest yield of oil (ca. 23%), while other wastes recorded yields of ca. 9%. Results of elemental analysis and column chromatography showed that pyrolysis oils could be used as fuel or chemical feedstock after re-treatment. The yields of carboneous residue (chars) were between 37.5% and 48.5% and their calorific value was between 4300 and 6000 kcal kg⁻¹, suitable for use as solid fuel. In addition, these chars were activated by CO₂ to obtain the activated carbon. The activated carbon having highest surface area (799.5 m² g⁻¹) was obtained from chromium-tanned shavings. Activated carbons prepared from chromium-tanned leather were presented as an adsorbant for the adsorption of dyes from aqueous solution.     

Pyrolysis Investigation For Bio-Oil Production From Various Biomass Feedstocks In Thailand

This study investigated the bio-oil production from vacuum pyrolysis of potential biomass feedstocks in Thailand. Experiments were carried out on palm empty fruit bunch, rice straw, rice husk, eucalyptus wood, rubber wood (Hevea Brasiliensis), and Teng wood (Shorea Obtuse) in a lab-scale-fixed bed reactor. The results showed that the product distribution was strongly dependent on temperature and biomass properties. Maximum oil yields, i.e., 50–60 wt %, were reached at 450–550°C. Due to mild temperature, most of alkalis originally present in biomass concentrated in product char, and only traces were detected in oil. Two-third of energy in biomass was in the product oil.     

Optimization of activated carbon production from empty fruit bunch fibers in one-step steam pyrolysis for cadmium removal from aqueous solution

The fast growth of the palm oil industry in Malaysia is associated with various waste products, namely the empty fruit bunches (EFB), which have a negative impact on the environment. Therefore, these wastes were utilized as a cheap raw material for the production of activated carbon (AC) with less energy consumption. One-step steam pyrolysis was used to produce AC from oil palm empty fruit bunch fibers (EFBF) by varying the operating parameters of temperature, steam flow rate, and activation time using two-level full factorial experimental design (FFD). Ten samples of AC were prepared and the optimized production conditions were chosen based on the ability to adsorb and remove cadmium. Physical activation comprised of carbonization for 30 min using nitrogen gas (N₂), followed by activation with steam at different flow rates (2.0, 3.0, and 4.0 ml/min), temperatures (600, 750, and 900°C) and times (15, 30, and 45 min). The AC sample produced at an activation temperature of 900°C with a steam flow rate of 2.0 ml/min and activation time of 15 min was selected as the best adsorbent with a total yield of 21.7%. It had adsorbed more than 97% of total cadmium from aqueous solution within 2 min of the contact time. Characterization of EFBF-based AC by SEM and BET surface area analysis had shown a good-quality adsorbent with highly active sites and well-developed pores with BET surface area of 635.16 m²/g. Experimental results indicated that the prepared AC from EFBF provide a promising solution in water and wastewater treatment.     

含油污泥资源化技术研究进展＊

含油污泥资源化技术的研究,应该重视多种热源热解技术开发,包括微波热解技术的研究。文章着重对含油污泥热解技术的研究进行了总结,包括微波热解技术的进展情况。研究得出:热解技术有望在固体废物处置及其资源化、有机质热解作低碳能源等方面发挥越来越重要的作用。开展含油污泥资源化研究,对解决我国国民经济持续发展过程中面临的能源短缺和环境挑战问题具有重要意义。     

含油污泥的热解处理与利用

文章对油田和炼油含油污泥进行了热解处理室内实验,测定了回收油气组成、热解残渣含碳量和Al2O3含量,开展了热解残渣对沥青的吸附性能和再生处理的絮凝性能测试分析。结果表明,含油污泥热解处理具有较好的油气回收和残渣再生利用价值,可实现污泥“零排放”,具有显著的直接经济效益和社会效益。污泥热解的产油率一般可达10%以上,废白土可达20%～30%,油回收率高;污水处理污泥热解残渣的Al2O3含量可达20%以上,有较高的铝含量,初步再生评价对污水有较好的絮凝作用,可再生循环利用;废白土热解残渣的吸附性能与活性白土相当,可循环使用。     

生物质在固定床中的热解试验研究

介绍了用于生物质热解的试验装置及试验方法，研究了升温速率、热解温度两种关键因素对生物质热解产物得率及其分桕的影响。研究结果表明，随热解温度的升高，热解产气量增加，且其中气体产品中的有效成分也在增加，焦油和半焦减少；升温速率增加，热解气得率增加，且气体中有效可燃成分增加。     

生物质热解影响因素研究

阐述了生物质的特点及其热解的定义和热解机理,综述了生物质热解过程中,温度、升温速率、物料特性（如种类、分子结构、粒径和颗粒形状等）、滞留时间、压力等操作条件对生物质热解及其产物分布组成和特性的影响,指出了生物质热解的技术关键。     

双回路立式垃圾热解炉试验研究

利用双回路立式热解焚烧炉对某地区的城市生活垃圾进行试验研究,结果表明,焚烧炉的二燃室温度能够达到850℃,烟气停留时间超过2s,燃烧灰的热灼减率小于3%。在废气排放口测到的数据表明：常规烟气的各种有害气体成分含量均能满足标准的要求;二噁英的含量不仅满足我国标准的要求,也远远低于欧盟的标准限值。     

油田含油污泥与芦苇共热解实验研究

以北方某油田湿地芦苇与油田某污水处理厂剩余污泥为对象,利用同步热分析仪及静态热解炉研究油田含油污泥及含油污泥-芦苇混合物的热解特性,将静态热解过程数据与同步热分析TG(热重分析)、DTG(微分热重分析)、DSC(差示扫描量热分析)曲线结合,计算了终止温度、产物量等。结果表明:不同含油污泥样品其产物生成率差别不大,热解TG、DTG和DSC曲线有较大差别,添加一定比例的芦苇可以使含油污泥热解过程变得匀速缓和,5%(质量比)的芦苇添加量可以使热解残渣恒重温度降低约25℃。混掺芦苇的样品残渣呈分散颗粒状,无聚结现象,对热解结焦将产生一定抑制作用。     

含油污泥热解处理的试验与应用

介绍了欢三联含油污泥热解处理工程的工艺流程、技术要点、设计参数、运行效果和效益情况。调试工作表明,热解炉系统工艺作为一个整体,能够稳定有效运行,残渣的测验结果表明,残渣可以达到无害化程度,含油率小于0.3%(满足GB 4284-84《农用污泥中污染物控制标准》的要求)。以12t/d的处理量运行,能耗成本为74.47元/t,产生的经济效益为125.50元/t,同时产生较好的社会效益。另外,热解固态产物也有较好的利用价值,可以进一步研究利用。     

含油污泥热解工艺技术方案研究

文章以辽河油田欢三联合站稠油污水处理系统压滤脱水污泥及沉降罐清罐污泥为处理对象,根据含油污泥热解处理的技术原理,通过对物料输送系统、热解反应系统、剩余固体排出系统和馏分冷凝分离系统等主要工艺单元的技术比选,提出了"柱塞泵管道密闭输送、多燃烧器回转炉热解、高温馏分管式换热器冷凝、不凝气罗茨风机引送和湿式排渣"的含油污泥热解处理工艺技术方案。同时,文章还对污泥热解处理运行的能耗与费用做了简要理论分析。