Catalytic upgrading of biorefinery oil from micro-algae

Micro-algae are seen as one of the major future fuel sources. Culture and growth of oil rich micro-algae and catalytic process for the conversion of their crude oils or biomass is reviewed here. While there is a significant literature on growth and extraction of oil from the resultant biomass the literature on the problems of refining these oils is diverse and needs collation. It is clear that previous work has been focused on the two green algae Botryococcus braunii and Chlorella protothecoides containing terpenoid hydrocarbons and glyceryl lipids as their major crude oils, respectively, both of which will need different refinery technology for upgrading. Studies show a number of conventional catalysts in the petroleum refining industry including transition metals, zeolites, acid and base catalysts can be used with variable effect. These have been employed for cracking, hydrocracking, liquefaction, pyrolysis and transesterification processes to produce diesel, jet fuel and petrol (gasoline). However there is strong evidence that new nano-scale materials containing a high number of active sites and high surface areas may offer more potential.     

木质纤维素基平台化合物催化转化制备液体燃料及燃料添加剂

随着不可再生的石化资源的不断消耗以及生态环境的不断恶化,可再生资源和能源的开发和利用受到越来越多的重视。木质纤维素是地球上最丰富的可再生生物质资源,蕴藏量和产量巨大,具有广阔的开发利用前景。本文在介绍国内外木质纤维素资源开发利用研究的基础上,结合当今世界生物质能领域的研发现状,分别概述了经由呋喃类化合物及乙酰丙酸等木质纤维素基平台化合物分子,制备液体燃料和燃料添加剂的最新研究进展。在总结归纳合成途径的同时,分析了现阶段面临的主要问题及可能的解决办法,以期能为木质纤维素类生物质能源化利用的研究提供有益的参考与借鉴。     

Fabrication of titanosilicate pillared MFI zeolites with tailored catalytic activity

Titanosilicate pillared MFI zeolite nanosheets were successfully synthesized by infiltrating the mixed tetraethyl orthosilicate (TEOS)/tetrabutyl orthotitanate (TBOT) solvent into the gallery space between adjacent MFI zeolite layers. The obtained zeolite catalysts were characterized using powder X-ray diffraction, N₂ adsorption/desorption isotherms, scanning electron microscopy, transmission electron microscopy, ultraviolet–visible spectroscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy techniques. The H₂O₂ oxidation of dibenzothiophene (DBT) was used to evaluate the catalytic performance of the obtained titanosilicate pillared MFI zeolites. The conversion of DBT and selectivity of dibenzothiophene sulfone (DBTS) were most affected by the textural properties of the zeolites. This was attributed to the DBT and DBTS molecules being larger than micropores of the MFI zeolites. The conversion of DBT and yield of DBTS could be systematically tailored by tuning the molar ratio of the TEOS/TBOT solvent. These results implied that a balance between the meso- and microporosity of zeolites and tetrahedrally coordinated Ti(IV) active sites of titanosilicate pillars can be achieved for the preparation of desired catalysts during the oxidation of bulk S compounds.     

Current Trends in Pretreatment and Fractionation of Lignocellulose as Reflected in Industrial Patent Activities

The pretreatment process to disintegrate lignocellulose and to fractionate its three main components hemicellulose, cellulose, and lignin, is a crucial step to enable sustainable and economic value chains based on biomass feedstock. This review provides an overview of the recent patenting activities on pretreatment. Most of these activities focus on optimization of different known processes to improve economics, such as increased catalyst efficiency, effluents recirculation, or lignin valorization. However, also a number of patents and demonstration activities based on emerging concepts for pretreatments are observed.     

Hydrothermal catalytic production of fuels and chemicals from aquatic biomass

One of the promising avenues for biomass processing is the use of water as a reaction medium for wet or aquatic biomass. This review focuses on the hydrothermal catalytic production of fuels and chemicals from aquatic biomass. Two different regimes for conversion of aquatic biomass in hydrothermal conditions are discussed in detail. The first is hydrothermal liquefaction, and the second is hydrothermal gasification. The goals of these processes are to produce liquid‐fuel‐range hydrocarbons and methane or hydrogen, respectively. The catalytic upgrading of biocrude resulting from noncatalytic liquefaction and the stability and degradation of catalysts in high temperature water are also discussed. The review concludes with a brief discussion of the outlook for and opportunities within the field of hydrothermal catalytic valorization of biomass. Copyright © 2012 Society of Chemical Industry     

A review of Canadian wood conversion technologies for the production of fuels and chemicals

Canada has 347 million ha of forest cover, contributing to the potential large availability of wood-based resources. Although Canada's forest sector contributed $23.7 billion to the national nominal gross domestic product (GDP) in 2019, the GDP contribution of the wood product manufacturing subsector shrank by 6%. To reposition the Canadian forest industry, new forest management practices and wood-based conversion technologies should be applied. In this context, the use of woody biomass in biorefineries to produce clean energy, fuels, and chemicals is becoming increasingly significant. There is a need to understand the current status and challenges of the wood-based biomass conversion technologies that have been and are being developed in Canada. This information will help decision-makers in formulating and implementing forest sector-related policies for a sustainable bioeconomy in Canada. This study is focused on a review of Canadian woody biomass conversion technologies. Our critical review identified considerable potential biomass conversion technologies specialized for woody feedstock, all in the Canadian setting. We focused on the prospects of revitalizing Canada's pulp and paper industry through the integration of pre-treatment processes and biochemical technologies. The thermochemical conversion pathway was identified as the dominant route for woody feedstock valorization. The review also identified pathways with the potential to diversify the existing product mix that generate products from wood streams, such as chemicals and biomaterials. Most of the biochemical and thermochemical research done in institutional and multi-institutional research collaborations from laboratory scale to industrial scale will boost the chances of the commercialization of a wood-based biorefinery in Canada.     

Aromatization activity of gallium containing MFI and TON zeolite catalysts in n-butane conversion: Effects of gallium and reaction conditions

A kinetic study of n-butane conversion over acidic and gallium (Ga) containing MFI and TON zeolites has revealed that Ga active sites create a new pathway for aromatics formation via dehydrogenation reaction steps. This pathway does not involve bulky bimolecular hydrogen transfer steps of the aromatization process over acidic zeolites, and, as a consequence, leads to considerably higher enhancement of the aromatization activity of the one-dimensional TON catalyst when compared to the three-dimensional MFI catalyst. This finding highlights fundamentally different spatial requirements for alkane aromatization over acidic and Ga containing zeolites and indicates that the zeolites with severe spatial constraints could become very selective catalysts for alkane aromatization after their modification with Ga. It is anticipated that these results will initiate the search for new, highly selective aromatization catalysts based on zeolites with different structures. The second important finding of this work is the evolution of the aromatization activity of GaH-TON and GaH-MFI catalysts during n-butane reaction that is likely associated with formation of catalytically active Ga⁺ ions. In our study, this process was completed in about 15 min, i.e. much faster then similar processes that were reported earlier in the literature for the GaH-MFI catalysts. To the best of our knowledge, no data on the evolution of the aromatization activity was reported up to day for the one-dimensional GaH-TON catalysts.     

Modified Beta Zeolite as Catalyst for Fries Rearrangement Reaction

Modified beta zeolites were applied as catalysts for the Fries rearrangement reaction. The properties of the modified zeolites were characterized by NH₃-TPD, n-hexane and 1,2,4-trimethylbenzene adsorption. Modification with SiO₂ did not block the pores of the beta zeolite but reduced the number of acid sites on the surface. However, when the beta zeolite was modified with Ce₂O₃, the number of acid sites determined by NH₃-TPD increased, which indicated that new acid sites are created by the interaction of cerium oxide and zeolite. Modified beta zeolites and H-beta were applied as catalysts for the Fries rearrangement of phenol acetate. Reaction over H-beta has low selectivity and the catalyst is easily deactivated. SiO₂ modification of the catalyst increases the selectivity of the reaction but decreases the conversion. Ce₂O₃-modified beta zeolites show higher catalytic activity and rearrangement selectivity in the reaction than other catalysts. The stability of the catalyst is also improved after Ce₂O₃ modification. About 70% selectivity and 60-80% conversion can be achieved over 16 wt% Ce₂O₃-modified beta zeolite.     

Glycerol in subcritical and supercritical solvents

Glycerol conversion to added value chemicals is a research avenue that has attracted significant interest in recent years. The utilization of critical solvents such as water and organic solvents in critical conditions as well as subcritical conditions (or hot compressed solvent) and supercritical conditions can offer several advantages to batch processes and in continuous flow systems in view of their potential implementation in industry. This review has been aimed to highlight most recent key processes for glycerol valorization to valuable products using different types of catalysts and processes. © 2016 Society of Chemical Industry     

Hydrophobic aluminosilicate zeolites as highly efficient catalysts for the dehydration of alcohols

Efficient dehydration of alcohols to olefins, acting as a control step in the upgrading of phenolic biofuel into alkane fuels, is an important topic in biomass conversion. Here, we report the design and synthesis of hydrophobic aluminosilicate ZSM-5 zeolites by an organosilane-modification approach (ZSM-5-OS). Water-droplet contact angle tests confirm the formation of hydrophobic surface after the modification. Interestingly, the obtained ZSM-5-OS catalysts exhibit excellent catalytic properties in dehydration of various alcohols into the corresponding olefins in water solvent. The approach reported in this work would be potentially important for developing more efficient catalysts for biomass conversion in the future.     

Recent research progress on bio-oil conversion into bio-fuels and raw chemicals: a review

Recent advances in lignocellulosic biomass valorization for producing fuels and commodities (olefins and BTX aromatics) are gathered in this paper, with a focus on the conversion of bio-oil (produced by fast pyrolysis of biomass). The main valorization routes are: (i) conditioning of bio-oil (by esterification, aldol condensation, ketonization, in situ cracking, and mild hydrodeoxygenation) for its use as a fuel or stable raw material for further catalytic processing; (ii) production of fuels by deep hydrodeoxygenation; (iii) ex situ catalytic cracking (in line) of the volatiles produced in biomass pyrolysis, aimed at the selective production of olefins and aromatics; (iv) cracking of raw bio-oil in units designed with specific objectives concerning selectivity; and (v) processing in fluidized bed catalytic cracking (FCC) units. This review deals with the technological evolution of these routes, in terms of catalysts, reaction conditions, reactors, and product yields. A study has been carried out on the current state-of-knowledge of the technological capacity, advantages and disadvantages of the different routes, as well as on the prospects for the implementation of each route within the scope of the Sustainable Refinery. © 2018 Society of Chemical Industry     

Sn-Beta沸石合成研究进展

含强L酸中心的Sn-Beta沸石在生物质平台化合物转化中表现出独特的活性和选择性,具有广阔的应用前景。Sn-Beta沸石主要合成方法有干胶法、水热法和同晶取代法。不同方法制备的Sn-Beta沸石Sn活性位的微环境及酸性质存在差异,在反应中表现出不同的反应性能。主要介绍Sn-Beta沸石合成方法及控制合成的影响因素。     

A systematic methodology for optimal mixture design in an integrated biorefinery

Biomass is a sustainable source of energy which can be utilised to produce value-added products such as biochemical products and biomaterials. In order to produce a sustainable supply of such value-added products, an integrated biorefinery is required. An integrated biorefinery is a processing facility that integrates multiple biomass conversion pathways to produce value-added products. To date, various biomass conversion pathways are available to convert biomass into a wide range of products. Due to the large number of available pathways, various systematic screening tools have been developed to address the process design aspect of an integrated biorefinery. Process design however, is often inter-linked with product design as it is important to identify the optimal molecule (based on desired product properties) prior to designing its optimal production routes. In cases where the desired product properties cannot be met by a single component chemical product, a mixture of chemicals would be required. In this respect, product and process design decisions would be a challenging task for an integrated biorefinery. In this work, a novel two-stage optimisation approach is developed to identify the optimal conversion pathways in an integrated biorefinery to convert biomass into the optimal mixtures in terms of target product properties. In the first stage, the optimal mixture is designed via computer-aided molecular design (CAMD) technique. CAMD technique is a reverse engineering approach which predicts the molecules with optimal properties using property prediction models. Different classes of property models such as group contribution (GC) models and quantitative structure property relationship (QSPR) are adapted in this work. The main component of the mixture is first determined from the target product properties. This is followed by the identifying of additive components to form an optimal mixture with the main component based on the desired product properties. Once the optimal mixture is determined, the second stage identifies the optimal conversion pathways via superstructural mathematical optimisation approach. With such approach, the optimal conversion pathways can be determined based on different optimisation objectives (e.g. highest product yield, lowest environmental impact etc.). To illustrate the proposed methodology, a case study on the design of fuel additives as a mixture of different molecules from palm-based biomass is presented. With the developed methodology, optimal fuel additives are designed based on optimal target properties. Once the optimal fuel additives are designed, the optimal conversion pathways in terms of highest product yield and economic performance that convert biomass into the optimal fuel additives are identified.     

Forty Years of Designing Catalytic and Adsorptive Sites in FAU Type Zeolites at K.U. Leuven

An overview of scientific achievements at K.U. Leuven on the design and characterization of active sites in X and Y zeolites and on the development of adsorptive and catalytic processes in which these active sites are operated is provided. The historical development of this research area and the scientific progress are presented. Zeolite Y and ultrastabilized specimen present Brønsted and Lewis sites that can be operated in vapor and liquid phase hydrocarbon conversion processes, bifunctional catalysis, epoxidation and ring opening of epoxides. Examples of molecular shape selective catalysis with Y zeolites are presented. The redox chemistry of transition metal exchanged faujasites is understood in great detail and has been exploited in Wacker chemistry and water splitting in a photochemical-thermal cycle. Selective adsorbents were designed based on knowledge of cation siting in X and Y zeolites. The occlusion of coordination compounds in the faujasite supercages is a means of creating unique active sites. Catalytic oxidative properties of the enzymes can be mimicked by embedding zeozyme in a hydrophobic membrane.     

Catalytic Production of Liquid Fuels from Biomass‐Derived Oxygenated Hydrocarbons: Catalytic Coupling at Multiple Length Scales

The catalytic processing of biomass‐derived feedstocks to liquid fuels and chemical intermediates is complex and expensive. Therefore, conversion processes involving a limited number of reaction, separation, and purification steps are necessary. Coupling of catalytic processes has the potential to lead to the development of new processes, thereby improving the overall economics of biomass conversion. Functional coupling at the molecular scale has the potential to produce novel catalytic materials to replace homogeneous catalysts. Active site coupling of different sites within the same reactor can help reduce operating costs by combining sequential reactions in a single reactor. Chemical reaction coupling of heterogeneous and homogeneous reactions may lead to improvements in overall catalytic performance for liquid phase processes by enhancing surface reactions with liquid phase reactions. Finally, phase coupling leads to improvements in overall yield by improving the equilibrium conversion or by suppressing undesired side reactions.     

基于过程模拟和随机森林模型的生物质制氢过程因素分析与预测

生物质可以替代化石燃料,减少温室气体排放,是一种有前途的可再生能源。生物质通过化学链气化制备氢气,碳化活化制备活性炭,两条工艺路线耦合可以联产绿色能源氢气和具有高附加值的活性炭,但是原材料选择和工艺参数优化成为规模化生产的主要障碍。在生物质联产氢气和活性炭工艺模型的基础上,建立高性能的随机森林预测模型,并探究生物质组分、工艺参数和过程产物对联产工艺的相对重要性。结果表明：生物质组分中的灰分、碳元素、氢元素的含量以及气体重整温度和水蒸气用量是准确预测氢气浓度和产量的重要影响因素。其中,重整温度、合成气中氢气浓度、水蒸气用量三个影响因素对氢气浓度的影响高达61%,活化剂用量、水蒸气用量两个因素对氢气产量的影响高达63%。此外,基于随机森林模型对生物质制氢过程中的因素进行分析和优化,可以实现氢气浓度达到96.8%(体积)。     

Acylation of Ferrocene with Adamantoyl Chloride and Cinnamoyl Chloride

Liquid phase acylation of ferrocene with adamantoyl and cinnamoyl chloride was studied over different structural types of zeolites. The effect of the zeolite structure and acidity, and the influence of the reaction conditions on the ferrocene conversion and selectivity was investigated. The highest ferrocene conversions were achieved over zeolite Beta with Si/Al ratio 12.5 (cinnamoyl chloride 63.5%, adamantoyl chloride 45.9%). It was observed that with decreasing concentration of active sites in zeolite Beta the ferrocene conversion decreases. In addition, it was found that there is an optimum molar ratio of ferrocene to acylating agent, the ferrocene conversion increased with increasing temperature and amount of catalyst. The most important finding is that acylation of ferrocene with adamantoyl and cinnamoyl chloride leads exclusively to monoacylated products, most probably due to a deactivation of the cyclopentadiene rings after the attachment of the first acyl group.