Chromatographic characterization of thermally upgraded products from alternative fuels

An overview is presented of the analytical approaches developed by our research group over the last ten years for analysis of alternative fuel, both biomass and fossil. The alternative fuels are analyzed successively by PLC-8 (preparative liquid chromatography–group-type) fractionation and high resolution gas chromatography. Some of the possibilities for fractionation and characterization of alternative fuels are herein exemplified with sugar cane bagasse pyrolysis products.     

Macroscopic mass and energy balance of a pilot plant anaerobic bioreactor operated under thermophilic conditions

Intensive poultry production generates over 100,000 t of litter annually in West Virginia and 9×10⁶ t nationwide. Current available technological alternatives based on thermophilic anaerobic digestion for residuals treatment are diverse. A modification of the typical continuous stirred tank reactor is a promising process being relatively stable and owing to its capability to manage considerable amounts of residuals at low operational cost. A 40-m³ pilot plant digester was used for performance evaluation considering energy input and methane production. Results suggest some changes to the pilot plant configuration are necessary to reduce power consumption although maximizing biodigester performance.     

Optimization of inoculum to substrate ratio for enhanced methane yield from leather fleshings in a batch study

One of the most significant issues of the last few decades has been tracing for renewable energy sources. Animal fleshing (ANFL) is the most common proteinaceous solid waste accured during the production of leather and it must be disposed of in an environmentally responsible manner. This paper is attempts to assess the biogas production from solid waste originating from the chrome based tannery. Anaerobic digestion of these wastes will be a viable option for waste stabilization and energy production in the form of biogas to be utilized in the industry. The bio-methane potential of the wastes were examined by mixing these wastes with various sources of inoculum and different inoculum to substrate (I/S) ratio considered. The batch experiments were carried out in 2.5 l glass reactors with a various source of inoculumviz., Cow Dung (CD), Elephant Dung (ED) and Bio-Digested Slurry (BDS) with varied inoculum to substrate (LFs) ratios for a retention time of 50 days with replications. The results obtained from the experiments showed that BDS:LF (25:75) had the highest gas production of 14505 ml (651.85 ml CH₄g^?1 VS) followed by CD:LF (50:50) produced 12072.5 ml (789.36 ml CH₄g^?1 VS) and ED:LF (75:25) produced 11252.5 ml (1492.08 ml CH₄g^?1 VS)with a methane content of 63.77, 61.92 and 62.72%, respectively.     

Production and energetic use of biogas from energy crops and wastes in Germany

The production of biogas for reducing fossil CO₂ emissions is one of the key strategic issues of the German government and has resulted in the development of new process techniques and new technologies for the energetic use of biogas. Progress has been made in cultivating energy crops for biogas production, in using new reactor systems for anaerobic digestion, and in applying more efficient technologies for combined heat and power production. Recently, integration of fuel cells within the anaerobic digestion process was started, and new technologies for biogas upgrading and conversion to hydrogen were tested. This article describes the trends in Germany for achieving more efficient energy production.     

A History of Fischer-Tropsch Wax Upgrading at BP—— from Catalyst Screening Studies to Full Scale Demonstration in Alaska

Conversion of Fischer-Tropsch wax into high quality synthetic crude or finished transportation fuels such as premium diesel has been studied over the past 15 years within BP. Catalyst screening and selection was carried out in dedicated micro-reactors and pilot plants, whose designs are critical to the performance selection. Variation in catalyst composition and defining the gas to oil feed ratios with the operating temperature are a few of the parameters studied. Product selection and maximizing diesel yield combined with stability (catalyst life) were the ultimate drivers. The selected catalyst was then tested under commercial conditions in a dedicated 300 barrel per day demonstration plant. The products were also tested in engines to assess their combustion characteristics.     

Aqueous-phase catalytic hydrogenation of furfural to cyclopentanol over Cu-Mg-Al hydrotalcites derived catalysts: Model reaction for upgrading of bio-oil

A series of Cu-Mg-Al hydrotalcites derived oxides with a (Cu+Mg)/Al mole ratio of 3 and varied Cu/Mg mole ratio (from 0.07 to 0.30) were prepared by co-precipitation and calcination methods, then they were introduced to the hydrogenation of furfural in aqueous-phase. Effects of Cu/Mg mole ratio, reaction temperature, initial hydrogen pressure, reaction time and catalyst amount on the conversion rate of furfural as well as the selectivity toward desired product cyclopentanol were systematically investigated. The conversion of furfural over calcined hydrotalcite catalyst with a Cu/Mg mole ratio of 0.2 was up to 98.5% when the reaction was carried out under 140 °C and the initial hydrogen pressure of 4 MPa for 10 h, while the selectivity toward cyclopentanol was up to 94.8%. The catalysts were characterized by XRD and SEM. XRD diffraction of all the samples showed characteristic pattern of hydrotalcite with varied peak intensity as a result of different Cu content. The catalytic activity was improved gradually with the increase of Cu component in the hydrotalcite.     

电催化氧化制备2,5-呋喃二甲酸

在第75届联合国大会上,我国承诺力争在2030年前实现碳达峰、2060年前实现碳中和。主要由光合作用产生的生物质将在双碳目标中扮演重要角色,通过高效转化可衍生出一系列替代化石产品的高值化学品。其中,2,5-呋喃二甲酸(FDCA)由于具有与石油基对苯二甲酸(TPA)相似的共轭碳环和二酸结构,可替代TPA用于合成热稳定性能、气体阻隔性能更优的生物基呋喃聚酯,大幅降低聚酯行业对化石资源的严重依赖。此外,FDCA在医药、香料、金属配位化学方面也有广泛应用,从而被认为是12种最具潜力的生物基平台化合物之一。FDCA通常可由5-羟甲基糠醛(HMF)通过催化氧化进行合成。相比于需要贵金属催化剂、高温和高压条件、以化学势作为驱动力的传统热催化方法,电催化氧化采用电极电势作为主要驱动力,是更为绿色和高效的新颖合成方法。本综述对电催化氧化制备FDCA反应所用的贵金属、过渡金属和非金属催化剂进行了总结与分析,梳理了催化剂设计和反应机理的研究脉络,并指出了该领域发展所面临的挑战与机遇。     

生物质快速热解制备液体燃料

本文回顾了生物质快速热解液化技术的国内外研究现状,重点叙述了初级生物油的化学组成和燃料性质,指出生物油是一种复杂的含氧有机混合物,具有水分含量高、氧含量高、热值低、酸含量高、安定性差和化石燃油不互溶等独特的性质;针对这些性质,介绍了几种常用的生物油精制提炼方法,包括催化裂解、催化加氢、高温热解气过滤、添加助剂、催化酯化、柴油乳化以及制备富氢合成气与费托合成,并分析了各种精制技术发展的关键问题。     

减压蒸馏生物油与乙醇在ZSM-5/MCM-41上共催化裂化

采用减压蒸馏生物油为原料,与无水乙醇2:3(质量比)混合,在固定床中ZSM-5/MCM-41分子筛上共催化裂化,考查了反应温度和质量空速(WHSV)对裂化产物的影响。对ZSM-5/MCM-41进行了NH₃-TPD、BET、N₂吸附-脱附等表征,对裂化气体产物通过气相色谱仪分析,减压蒸馏生物油和精制生物油采用气相色谱-质谱联用仪进行定量分析。结果表明,反应温度500 ℃、WHSV 3.75 h^-1为反应优化工况。此反应条件下,精制生物油酸类物质从减压蒸馏生物油中的25.6%降至反应后的0.1%,效果显著,且精制生物油产率为46.8%,气体产物中CO₂和CO的浓度共9.5%。     

Facile analysis of short-chain fatty acids as 4-nitrophenyl esters in complex anaerobic fermentation samples by high performance liquid chromatography

Short-chain fatty acids are crucial intermediates in the conversion of biomass to methane. Due to the complexity of raw biomass, volatile fatty acids (including n- and branched-chain compounds) as well as arylacetic and arylpropionic acids arise from digestion of carbohydrates, proteins and lipids. The development of a simple extraction procedure in combination with internal standardization and facile 4-nitrophenyl-labelling via oxalylchloride-generated acylchlorides enabled robust separation and quantification of the target compounds in crude biological samples like raw cattle manure and biogas fermenter contents. Detection limits of <100 μM and error rates of less than 4% for the quantification of individual compounds in a concentration range up to 50 mM for non-diluted samples suggest that the novel method might be of general advantage for the routine quantification of short-chain fatty acids in complex biological samples including complex fermentation media.