Sustainable economic and industrial growth requires safe, sustainable resources of energy. For the future re-arrangement of a sustainable economy to biological raw materials, completely new approaches in research and development, production, and economy are necessary. The ‘first-generation’ biofuels appear unsustainable because of the potential stress that their production places on food commodities. For organic chemicals and materials these needs to follow a biorefinery model under environmentally sustainable conditions. Where these operate at present, their product range is largely limited to simple materials (i.e. cellulose, ethanol, and biofuels). Second generation biorefineries need to build on the need for sustainable chemical products through modern and proven green chemical technologies such as bioprocessing including pyrolysis, Fisher Tropsch, and other catalytic processes in order to make more complex molecules and materials on which a future sustainable society will be based. This review focus on cost effective technologies and the processes to convert biomass into useful liquid biofuels and bioproducts, with particular focus on some biorefinery concepts based on different feedstocks aiming at the integral utilization of these feedstocks for the production of value added chemicals.

http://staff.cimap.res.in/PublicationFiles/Renew_Sustain_Energ_Rev_14_578.pdf

Production of first and second generation biofuels: A comprehensive review

This critical review provides a survey illustrated by recent references of different strategies to achieve a sustainable conversion of biomass to bioproducts. Because of the huge number of chemical products that can be potentially manufactured, a selection of starting materials and targeted chemicals has been done. Also, thermochemical conversion processes such as biomass pyrolysis or gasification as well as the synthesis of biofuels were not considered. The synthesis of chemicals by conversion of platform molecules obtained by depolymerisation and fermentation of biopolymers is presently the most widely envisioned approach. Successful catalytic conversion of these building blocks into intermediates, specialties and fine chemicals will be examined. However, the platform molecule value chain is in competition with well-optimised, cost-effective synthesis routes from fossil resources to produce chemicals that have already a market. The literature covering alternative value chains whereby biopolymers are converted in one or few steps to functional materials will be analysed. This approach which does not require the use of isolated, pure chemicals is well adapted to produce high tonnage products, such as paper additives, paints, resins, foams, surfactants, lubricants, and plasticisers. Another objective of the review was to examine critically the green character of conversion processes because using renewables as raw materials does not exempt from abiding by green chemistry principles (368 references).

Conversion of biomass to selected chemical products

Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40th anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are dee...

Fundamentals and Catalytic Applications of CeO2-Based Materials

Lignocellulosic biomass pyrolysis mechanism: A state-of-the-art review

https://www.cell.com/trends/biotechnology/pdf/S0167-7799(06)00254-X.pdf

Bio-ethanol--the fuel of tomorrow from the residues of today.

Gasification of southern pine using carbon dioxide as an oxidizing medium was carried out in a bench-scale atmospheric bubbling fluidized bed gasifier, and the results were compared with an oxygen gasification study from literature. Evolution of gases (CO, CO2, H2, and CH4) was quantified as a function of temperature in the range 700 °C to 935 °C and CO2/C ratios in the range of 0.5–1.5 (wt/wt). The main aim of this study was to determine the effect of temperature and CO2/C ratios on the output syngas and to understand which reactions were influential within the operational limits of the experimental parameters. Additionally, results from CO2 gasification and oxygen gasification were thoroughly compared. Statistical analyses were performed to determine the significance of changes in operating parameters on the process. Variation in temperature seemed to have a significant effect on the output, whereas the effects of CO2/C ratios were not that profound. The analyses of the gas evolution trends suggested th...

Biomass Gasification Using Carbon Dioxide: Effect of Temperature, CO2/C Ratio, and the Study of Reactions Influencing the Process

A fast pyrolysis process has emerged as one of the techniques to produce transportation fuels using various biomass types that are regionally important. It is well understood that high heating rate...

Influence of Pyrolysis Operating Conditions on Bio-Oil Components: A Microscale Study in a Pyroprobe

Three-dimensional (3D) printing is a revolutionary manufacturing technique that can fabricate a 3D object by depositing materials layer by layer. Different materials such as metals, polymers, and concretes are generally used for 3D printing. In order to make 3D printing sustainable, researchers are working on the use of different bioderived materials for 3D printing. Because of the abundant and sustainable sources, and versatile properties, biomaterials are considered as the potential candidates that have the ability to replace petroleum-based polymers. This review highlights the basic overview of fused deposition modeling (FDM) technique of 3D printing and recent developments that have occurred on FDM printing using biomaterials. Specifically, FDM printing process, final properties, and characteristics of biopolymers, their composites, and polymers containing biofillers are discussed.

/pdf/use-of-biomaterials-for-3d-printing-by-fused-deposition-3mvm2l04d1.pdf

Use of Biomaterials for 3D Printing by Fused Deposition Modeling Technique: A Review

The objective of this paper is to investigate the biomass torrefaction effect on bio-oil stability by comparing the physicochemical and compositional properties of aged bio-oils. Two aging methods, accelerated aging (held at 80 °C for 24 h) and long-term natural aging (12-month storage at 25 °C), were employed to produce aged bio-oils for such comparison. The results indicate that bio-oils made from heat-treated wood had similar aging behavior in terms of increase of water content, acid content, molecular weight, and viscosity. The increase rate, however, was found to be different and dependent on the aging method. The accelerated method found parallel water and total acidity number (TAN) increments between raw and torrefaction bio-oils, while the natural aging method found torrefaction bio-oils, especially those made from heavily treated wood, had much slower water and acid accumulation than that of raw bio-oil. As a negative effect, both methods identified the viscosity of torrefaction bio-oils increase...

Thermal and Storage Stability of Bio-Oil from Pyrolysis of Torrefied Wood

pH control has been essential for butanol production with Clostridium acetobutylicum. However, it is not very clear at what pH level the acid crash will occur, at what pH level butanol production will be dominant, and at what pH level butyric acid production will be prevailing. Furthermore, contradictory results have been reported about required acidic conditions for initiation of solventogenesis. In this study, with the aim of further understanding the role of undissociated butyric acid in butanol production, we investigated the correlation between undissociated butyric acid concentration and specific butanol production rate in batch fermentation of Clostridium acetobutylicum by comparing three pH control approaches: NaOH neutralization (at 12, 24 or 36 h), CaCO3 supplementation (2, 5, or 8 g/l) and NaOAc buffering (pH 4.6, 5.0 or 5.6). By neutralizing the fermentation pH to ~5.0 at different time, we observed that neutralization should take place at the beginning of exponential phase (12 h), and otherwise resulting in lower concentrations of undissociated butyric acid, cell biomass and final butanol. CaCO3 supplementation extended cell growth to 36 h and resulted in higher butyrate yield under 8 g/L of CaCO3. In the NaOAc buffering, the highest specific butanol rate (0.58 h−1) was associated with the highest undissociated butyric acid (1.92 g/L). The linear correlation of the undissociated butyric acid with the specific butanol production rates suggested the undissociated butyric acid could be the major driving force for butanol production.

/pdf/a-comparison-of-three-ph-control-methods-for-revealing-4kpnv0pory.pdf

A comparison of three pH control methods for revealing effects of undissociated butyric acid on specific butanol production rate in batch fermentation of Clostridium acetobutylicum.

Sushil Adhikari

Papers

Biomass Gasification Using Carbon Dioxide: Effect of Temperature, CO2/C Ratio, and the Study of Reactions Influencing the Process

Influence of Pyrolysis Operating Conditions on Bio-Oil Components: A Microscale Study in a Pyroprobe

Use of Biomaterials for 3D Printing by Fused Deposition Modeling Technique: A Review

Thermal and Storage Stability of Bio-Oil from Pyrolysis of Torrefied Wood

A comparison of three pH control methods for revealing effects of undissociated butyric acid on specific butanol production rate in batch fermentation of Clostridium acetobutylicum.