N2 explosive decompression pretreatment of biomass for lignocellulosic ethanol production

This paper presents a novel biomass pretreatment method that uses high pressured N₂ and temperature to break the hemicellulose and lignin seal around the cellulose macro fibrils in the cell walls of the lignocellulosic biomass in order to open up the biomass structure for more efficient enzymatic hydrolysis. In this method the biomass is exposed to a high pressure using N₂ gas, and temperature. Under pressure, cells of the lignocellulosic biomass are filled with a solution saturated with nitrogen. When the pressure is then suddenly released, the feedstock is exposed to an explosive decompression and the dissolved nitrogen is released from the solution. Sudden change in the volume breaks the cell walls and opens the biomass structure resulting in increased surface area of the substrate for enzymatic hydrolysis. No catalysts or chemicals were added in the process thereby, making it economically and environmentally attractive. In this research, a range of different pressures (1–60 bar) and temperatures (25–175 °C) were applied to barley straw to evaluate the efficiency of the pretreatment. The pretreatment was followed by enzymatic hydrolysis and fermentation. Resulting glucose and ethanol concentrations were measured and the yields were considered as an estimate for the most suitable set of pretreatment conditions. The results indicate that the highest glucose yield and hydrolysis efficiency were gained at 150 °C and 10–30 bars. The fermentation efficiency was lower at higher temperatures. Nonetheless, the highest ethanol yield was still gained at the same conditions.     

Thermodynamic and experimental aspects on chemical looping reforming of ethanol for hydrogen production using a Cu‐based oxygen carrier

An investigation on the chemical looping reforming of ethanol process using Gibbs free energy minimization method was performed. It is found that the temperature, oxygen/ethanol molar ratio (OER), and pressure have pronounced influences on the product yields in chemical looping reforming of ethanol process. The ethanol conversion and H₂ yield are 100% and 2.25 mol mol^?1 ethanol, respectively, at 700 °C, OER of 1 and 1 atm. The higher temperatures promote H₂ and CO production, but the higher pressures and OERs have negative effect on the H₂ and CO generation. Favorable operation conditions are 1 atm, 700 °C, and OER = 1. The experimental tests were carried out in a fixed bed using a Cu‐based oxygen carrier prepared by impregnation method. Working at 1 atm, the H₂ concentration increased with an increase in temperature; however, it remained approximately with an increase in gas hourly space velocity. The H₂/CO molar ratio was between 3 and 5 in the period of 0–30 min at 1 atm and 700 °C. Copyright © 2013 John Wiley & Sons, Ltd.     

Interactions of mixing and reaction kinetics of depolymerization of cellulose to renewable fuels

As the biofuel industry is heavily depend on technological advancement to remain competent, creation of new process techniques becomes inevitable to replace the existing under-performed operations. Mixing in the reactor requires enormous amount of energy to achieve required homogeneity. Reduction in the energy consumption and ultimately the cost of the product is possible by devising smart mixing strategies. In this review, interactions of mixing and reaction kinetics of enzymatic hydrolysis, fermentation, and cellulosic depolymerization in ionic solvents are discussed. When the processes are operated under various mixing conditions, changes in the reaction kinetics and dynamics of the processes occur. Therefore, analyzing the mixing effects at various levels (micro to macro) is crucial to decide best operating mixing conditions that drive the reaction kinetics toward the increased product yield. The review is helpful to identify a suitable mixing strategy that maximizes the production of biofuels—ethanol, 5-hydroxymethylfurfural, etc.     

Environmental sustainability assessment of bioeconomy value chains

Bioeconomy has gained political momentum since 2012 when the European Commission adopted the strategy “Innovating for Sustainable Growth: A Bioeconomy for Europe”. Assessing the environmental performance of different bioeconomy value chains (divided in three pillars: food and feed, bio-based products and bioenergy) is key to facilitate solid and evidence-based policy making. The objectives of this work were: (1) to map and analyse accessible LCA data related to bioeconomy value chains in order to identify knowledge gaps; (2) provide a more robust and complete picture of the environmental performance of three bioeconomy value chains (i.e. one per each bioeconomy pillar). This analysis reveals that apart from few products (such as liquid biofuels, some biopolymers and food crops) the environmental assessment of bioeconomy value chains is still incipient and limited to few indicators (e.g. Global Warming Potential and energy efficiency). In this study, a harmonised procedure – the Product Environmental Footprint (PEF), which includes fourteen impact categories – is used to estimate the environmental performance of three exemplary case studies which are inter-related due to the use of sugar as feedstock: sugar (food and feed), bio-based ethanol (bioenergy) and polyhydroxyalkanoates (bio-based product). Results highlight the strong need for methodological harmonisation and coherence for LCA of bioeconomy value chains.     

Comprehensive analysis on anomalous phenomenon of ethanol-soluble poly(vinyl butyral) membrane for ethanol recovery via pervaporation

Poly(vinyl butyral) (PVB) is selected as a promising ethanol-permselective membrane based on the solubility parameter theory; however, it exhibits anomalous water perm-selectivity in practical pervaporation (PV) process. Comprehensive analysis based on experimental and theoretical methods were carried out to explore the inherent mechanism of the anomalous performance. Firstly, sum frequency generation vibrational spectra and contact angle were developed to quantify the surface reconstruction of membrane in air and ethanol, which indicated that hydrophilic hydroxyl tended to expose on membrane surface with ethanol thus improving the membrane affinity to water. Meanwhile, swelling behaviors proved more water would accumulate in the ethanol swollen membrane. Furthermore, theoretical analysis in terms of sorption and diffusion process, based on the UNIFAC-FV model and Fujita free-volume theory, confirmed the mechanism of anomalous phenomenon of PVB membrane. The comprehensive investigation was expected to provide insights into the basic separation mechanism of PV process.     

The effect of ethanol on the formation and physico-chemical properties of particles generated from budesonide solution-based pressurized metered-dose inhalers

The aerosol performance of budesonide solution-based pressurized metered-dose inhalers (HFA 134a), with various amounts of ethanol (5–30%, w/w) as co-solvents, was evaluated using impaction and laser diffraction techniques. With the increase of ethanol concentration in a formulation, the mass median aerodynamic diameter was increased and the fine particle fraction showed a significant decline. Although data obtained from laser diffraction oversized that of the impaction measurements, good correlations were established between the two sets of data. Particles emitted from all the five formulations in this study were amorphous, with two different types of morphology – the majority had a smooth surface with a solid core and the others were internally porous with coral-like surface morphology. The addition of ethanol in the formulation decreased the percentage of such irregular-shape particles from 52% to 2.5% approximately, when the ethanol concentration was increased from 5% to 30%, respectively. A hypothesis regarding the possible particle formation mechanisms was also established. Due to the difference of droplet composition from the designed formulation during the atomization process, the two types of particle may have gone through distinct drying processes: both droplets will have a very short period of co-evaporation, droplets with less ethanol may be dried during such period; while the droplets containing more ethanol will undergo an extra condensation stage before the final particle formation.     

双（三环己基膦）氯化钯的合成及其结构表征

以氯亚钯酸钠与三环己基膦为原料，在乙醇介质中合成双（三环己基膦）氯化钯，该合成过程简单、绿色环保和对设备要求低。采用元素分析、红外光谱以及核磁共振磷谱等表征合成样品的组成与结构,结果表明，在三环己基膦与氯亚钯酸钠物质的量比大于2.4和反应温度70 ℃条件下，双（三环己基膦）氯化钯收率达99.6%，且纯度较高。     

Optimal design of catalytic distillation columns: A case study on synthesis of TAEE

The design of catalytic distillation (CD) columns is a challenging task because of the superposition of chemical reaction and distillation in one apparatus. In this work, a method to design a cost-optimal CD column for chemical systems with large number of components and chemical reactions is presented. The method is based on the following steps: (1) estimation of the number of theoretical stages and catalyst volume by the decomposition of the CD column into a sequence of chemical reactors and non-reactive distillation columns, (2) estimation of the column diameter and operating conditions using an equilibrium stage model, and (3) design of the column applying an optimisation algorithm and using a rigorous non-equilibrium stage model to represent the CD process. The method is applied to determine the optimal column configuration and operating conditions for the synthesis of tert-amyl ethyl ether from ethanol and isoamylenes. Eight components and four chemical reactions were selected to represent the chemical system in the simulations.