Second-generation Biomass Research Articles

Design of sustainable second-generation biomass supply chains

Operational and economic trade-offs in the design of second-generation biomass (SGB) supply chains guide the decisions about plant scale and location as well as biomass collection routes. This paper compares different SGB supply chain designs with a focus on mobile pyrolysis plants and centralized versus decentralized collection of biomass in terms of economic and environmental sustainability. Pyrolysis scenarios are also compared to fuel-upgrading and electricity production scenarios.The empirical context of this paper is based on a scenario analysis for processing lignocellulosic biomass, particularly landscape wood, reed and roadside grass available in the Overijssel region (Eastern Netherlands). Four scenarios are compared: (1) mobile pyrolysis plant processes the locally available biomass on-site into pyrolysis oil which is sent to a regional biofuel production unit for upgrading to marketable biofuel; (2) local biomass is collected and transported to a regional pyrolysis-based biofuel production unit for upgrading to a marketable biofuel; (3) mobile pyrolysis plant performs the on-site conversion to pyrolysis oil which is transported to an oil refinery outside the region (Rotterdam); and (4) collected biomass is sent to the nearest electricity production unit to generate electricity.The results show that processing SGB is costly and upgraded oil and refined oil are at least 65% more expensive compared to their fossil counterparts. In terms of economic and environmental performance, the mobile plant performs slightly better than a fixed plant. The energy output/input ratio range is between 6.99 and 7.54 and CO2 emissions range is between 96 and 138 kg CO2/t upgraded oil.

Valorization of Sugar Cane Bagasse and Jatropha Curcas Cake: Production of a Biocrude by Acetylation Reaction under Microwave Radiation

Second-generation biomass has been proposed as an alternative way to provide sustainable energy. However, the transformation of biomass into liquid by thermoconversion introduces several drawbacks in the bio-oil. A new approach to convert biomass into a more stable and less polar biocrude compared to fast pyrolysis bio-oil was recently developed, which is based on hydrolysis/functionalization of biomass carbohydrates. This work describes the transformation of sugar cane bagasse and Jatropha curcas cake in biocrude through the acetylation reaction under microwave radiation, in the presence of acetic anhydride and a catalytic amount of sulfuric acid. The reaction conditions were broadly investigated and moderate to complete conversion of the biomasses was achieved; however, Jatropha curcas was more resistant than sugar cane to the hydrolysis/acetylation reaction. The produced biocrudes were thoroughly characterized, and polyacetylated carbohydrates were the main products identified.

Gasoline from biomass through refinery-friendly carbohydrate-based bio-oil produced by ketalization.

The introduction of biomass-derived compounds as an alternative feed into the refinery structure that already exists can potentially converge energy uses with ecological sustainability. Herein, we present an approach to produce a bio-oil based on carbohydrate-derived isopropylidene ketals obtained by reaction with acetone under acidic conditions directly from second-generation biomass. The obtained bio-oil showed a greater chemical inertness and miscibility with gasoil than typical bio-oil from fast pyrolysis. Catalytic upgrading of the bio-oil over zeolites (USY and Beta) yielded gasoline with a high octane number. Moreover, the co-processing of gasoil and bio-oil improved the gasoline yield and quality compared to pure gasoil and also reduced the amount of oxygenated compounds and coke compared with pure bio-oil, which demonstrates a synergistic effect.

Overview of technical barriers and implementation of cellulosic ethanol in the U.S.

There is mounting concern about the buildup of carbon dioxide (CO2) and other so-called greenhouse gases in the atmosphere. In general, bioethanol production requires minimal fossil fuel input in the conversion step, and ethanol is considered a promising alternative fuel to petroleum-derived products. It is anticipated that ethanol production with second-generation biomass, i.e. lignocellulosic materials, will be possible on a large scale in the near future. Latest efforts have been focused on overcoming technical challenges in bioconversion, particularly pretreatment, and finding the solutions required to implement biorefinery on a large scale. This paper introduces and reviews the current status of research, and of the ethanol industry in the U.S. In addition, other important concepts in biofuels, cellulosic ethanol, and biorefinery in general are reviewed, and the key technical issues in bioconversion of cellulosic ethanol, such as pretreatment and factors affecting bioconversion of biomass are also discussed.

Distillable Acid–Base Conjugate Ionic Liquids for Cellulose Dissolution and Processing

Future biorefinery concepts are seriously entertaining the use of ionic liquids (ILs) as a platform media for the processing of woody material as a second-generation biomass feedstock. The main motivation is the demonstrated efficiency of some molten salts in the dissolution of cellulose, a major structural and solvolytically resistant component of lignocellulosic materials. The first report of the use of molten salts for the modification of cellulose came in the form of a patent by Graenacher, where alkyl pyridinium chlorides were used to dissolve cellulose, thus allowing for efficient chemical modification from those media. The melting points of most alkyl pyridinium chloride salts are above 100 8C and, as such, these species do not fall under the common definition of ionic liquids. Nevertheless, the molten compounds solvated cellulose to such a state as to allow for acylation to a high degree. The next generational advance was the discovery by Rogers and co-workers that dialkyl imidazolium based ionic liquids, with melting points below 100 8C, can dissolve cellulose. The most successful of these was 1-butyl-3-methylimidazolium chloride ([bmim]Cl]). This advance was further refined by Ohno et al. into room-temperature ionic liquids capable of dissolving cellulose, such as 1-ethyl-3-methylimidazolium formate ([emim][CO2H]) [3a] or 1-ethyl-3-methylimidazolium dimethylphosphate ([emim][Me2PO4]). [3b] From the structures listed in the claims of the Rogers patent, BASF have also refined this list down to room-temperature ionic liquids, such as 1-ethyl-3-methylimidazolium acetate ([emim][OAc]). It has been reported by BASF, by oral dissemination and unofficial reports, that [emim][OAc] has higher dissolving efficiency for cellulose and has lower toxicity than structures such as [bmim]Cl. However, no detailed studies comparing chlorides with carboxylates or other such structures have been published, although certainly their undeniable high efficiency for dissolution and chemoselectivity has been demonstrated for a number of cellulose modification applications. Despite the high efficiency for the solvation of cellulose, lignin, and even wood in an increasing range of dialkyl imidazolium based ionic liquids, sustainability of prospective processes will depend on the chemical stability of solutes and ionic liquids under process and recycling conditions. There are already some indications that ionic liquids such as [emim][OAc] react chemically with lignocellulosic solutes. This reactivity may lower the recovery of the media upon recycling, although, in the case of the reaction of C2 imidazolium positions with C1 reducing end groups of cellulose, it is possible that this reaction is reversible under aqueous conditions, owing to the lability of the conjugate linkage. A bigger concern is the method of recycling to yield a pure ionic liquid. For most processes, high-purity ionic liquid will be required to maintain efficiency of dissolution and overall sustainability of the process. Decomposition of dialkyl imidazolium based ILs containing basic anions in the presence or absence of solutes proceeds according to three main pathways. From knowledge of the chemical stability of these cations, the pathways are most easily illustrated using a 1,3-diethylimidazolium cation ([eeim]) as countercation (Scheme 1).

UOP and Ensyn to form jv to offer second-generation biomass technology

Flash pyrolysis oil from an ENSYN RTP pilot plant was upgraded in a continuous bench scale unit with commercial CoMo and NiMo catalysts in anticipation of scaling up the process. Large amounts of product were produced in a pilot plant for use in an extended analytical characterisation programme.In bench-scale experiments, high deoxygenation rates of 88–99.9% were achieved. Low liquid and high water yields were obtained. The fractionated products of the production run did not fulfil the requirements for direct use as gasoline and diesel.The process is restricted by several operational problems such as rapid catalyst deactivation, coking and plugging. Due to high feedstock and hydrogen addition costs, pyrolysis upgraded oil by the process tested is significantly more expensive than petroleum-derived oil at present oil prices.