A viable technology to generate third‐generation biofuel

First generation biofuels are widely available because the production technologies are well developed. However, growth of the raw materials conflicts with food security, so that first‐ generation biofuels are not so promising. The second generation of biofuels will not compete directly with food but requires several energy intensive processes to produce them, and also increases land‐use change, which reduces its environmental and economic feasibility. The production of third‐generation biofuels avoids the issues met with first‐ and second‐ generation biofuels, namely food–fuel competition, land‐use change, etc., and is thus considered a viable alternative energy resource. On all dimensions of sustainability (environmental, social and economical), a life cycle assessment approach is most relevant to avoid issues in problem shifting. The utilization of organic waste and carbon dioxide in flue gases for the production of biomass further increases the sustainability of third generation biofuels, as it minimizes greenhouse gas emissions and disposal problems. Copyright © 2011 Society of Chemical Industry     

蔗渣纤维素乙醇的预处理技术研究进展

从蔗渣的物化特性及预处理的必要性出发,综述了近年来国内外预处理蔗渣方面发展的不同技术途径(包括物理法、化学法、生物法和联合法)及其研究进展,对各种技术的作用效果和特点进行了总结和对比分析,并对蔗渣预处理技术的发展方向予以展望。蔗渣作为糖厂的主要副产物,具有量大、集中且纤维含量高等特点,是生产第二代生物乙醇的重要潜在原料之一,对其进行有效预处理是利用其制取生物乙醇的关键,直接影响着后续的酶解糖化和乙醇发酵效果。     

Product diversification to enhance economic viability of second generation ethanol production in Brazil: The case of the sugar and ethanol joint production

Commercial simulator Aspen Plus^® was used to simulate the conventional processes of the autonomous distillery producing ethanol and the joint production of sugar and ethanol. Changes in conventional processes were evaluated to increase electricity and second generation ethanol production using bagasse fine fraction composed by parenchyma cells (P-fraction). The evaluated processes were thermal and water integrated. The results indicated that the integration of the second generation process to the conventional processes was possible after thermal and water integration. The economic analysis showed that the second generation process integrated to the joint production presented lower payback time, 2.3 years, in comparison with this process integrated to the autonomous distillery, 4.7 years. Due to the high enzyme costs, the cases without second generation ethanol production presented higher economic viability. Product diversification, as sugar and ethanol production in the same site, lowered the impact of enzymes cost on the payback time of second generation process, showing that the integration of the second generation ethanol production process to the conventional sugar production process could be a step to cellulosic ethanol production feasibility in sugarcane mills.     

Multi-period synthesis of optimally integrated biomass and bioenergy supply network

This contribution addresses the multi-period synthesis of an optimally integrated regional biomass and bioenergy supply network through a mixed-integer linear programing (MILP) approach. The production processes from different sources of biomass include first, second, and third generations of biofuels like bioethanol, biodiesel, hydrogen, Fischer Tropsch diesel, and green gasoline. The aim is to maximize the sustainably viable utilization of resources by accounting for the competition between fuels and food production. An MILP model for efficient bioenergy network optimization based on four layers is extended to include several features, such as seasonality and availability of resources, enabling recycles of products and total site heat integration in order to address real-world applications with a systematic decision-making approach. The multi-period optimization of a heat-integrated biorefinery's supply network is performed through maximization of the economic performance. Economically efficient solutions are obtained with optimal selection of raw materials, technologies, intermediate and final product flows, and reduced greenhouse-gas emissions.     

Sugarcane bagasse and leaves: foreseeable biomass of biofuel and bio‐products

Sugarcane is among the principal agricultural crops cultivated in tropical countries. The annual world production of sugarcane is ～1.6 billion tons, and it generates ～279 million metric tons (MMT) of biomass residues (bagasse and leaves). Sugarcane residues, particularly sugarcane bagasse (SB) and leaves (SL) have been explored for both biotechnological and non‐biotechnological applications. For the last three decades, SB and SL have been explored for use in lignocellulosic bioconversion, which offers opportunities for the economic utilization of residual substrates in the production of bioethanol and value‐added commercial products such as xylitol, specialty enzymes, organic acids, single‐cell protein, etc. However, there are still major technological and economic challenges to be addressed in the development of bio‐based commercial processes utilizing SB and SL as raw substrates. This article aims to explore SB and SL as cheaper sources of carbohydrates in the developing world for their industrial implications, their use in commercial products including commercial evaluation, and their potential to advance sustainable bio‐based fuel systems. Copyright © 2011 Society of Chemical Industry     

Rapeseed residues utilization for energy and 2nd generation biofuels

Lignocellulosic biomass is an interesting and necessary enlargement of the biomass used for the production of renewable biofuels. It is expected that second generation biofuels are more energy efficient than the ones of first generation, as a substrate that is able to completely transformed into energy. The present study is part of a research program aiming at the integrated utilization of rapeseed suitable to Greek conditions for biodiesel production and parallel use of its solid residues for energy and second generation biofuels production. In that context, fast pyrolysis at high temperature and fixed bed air gasification of the rapeseed residues were studied. Thermogravimetric analysis and kinetic study were also carried out. The obtained results indicated that high temperature pyrolysis could produces higher yields of syngas and hydrogen production comparing to air fixed bed gasification.     

Bioprocessing aspects of fuels and chemicals from biomass

This review deals with a recent development of biofuels and chemicals from biomass. Some of the grainbased biofuels and chemicals have already been in commercial operation, including fuel ethanol, biodiesel, 1.3-propanediol, polylactic acid (PLA) and polyhydroxy butyric acid/alkanoates (PHB/PHA). The next generation bioproducts will be based on lignocellulosics due to their abundance and to stabilize rising food prices. However, the technologies of handling biomass are yet in their infancy and suffer from low yield, low product titer, and low productivity. This review focuses on bioprocessing technologies for biofuels production: organic raw biomaterials available in Korea; volatile fatty acids platform, multi-stage continuous high cell density culture (MSC-HCDC), enrichment of fermentation broth by forward osmosis; various purification methods of pervaporation of ethanol, solvent extraction on succinic, lactic acids and reactive separation methods.     

New integrated scheme of the closed gas-turbine cycle with synthesis gas production

New integrated scheme of the closed gas-turbine cycle with synthesis gas production was proposed. A comparative exergy analysis of the traditional gas-fired power generation cycle and proposed integrated gas-turbine cycle with synthesis gas production was carried out. The exergy losses in compressors and turbines are evaluated by using intrinsic coefficients. It has been shown that the integration of power generation and synthesis gas production technologies is an effective method to increase the electric energy generation by 9-12% or reduce methane consumption in its conversion into synthesis gas by 18-23%. Such integration is especially favourable if synthesis gas production is considered at initial stage of liquid synthetic fuels producing.     

Low-cost small scale processing technologies for production applications in various environments—Mass produced factories

The requirements for chemical and food production technologies will change in the future as a result of shorter time to market and increasing market volatility. Especially the rising use of renewable resources will require the implementation of flexible and fast to install small-scale production technologies. The increasing number of necessary apparatuses and their distributed operation, however, will constitute major challenges, both economically and procedurally.The proposed solution to face the economic challenge is modularization and standardization. For food production, dewatering represents a key issue. Thus, biomass processing should first be divided into small-scale water separation steps and then into further large-scale processing steps. As dewatering usually happens thermally and heat exchangers often benefit from the economies of scale, heat supply and energy consumption or heat transfer with little capital investment are further issues. Therefore, temperature levels should be decreased and the use of solar heat increased. For the production of biofuels and chemicals from biomass, process integration and process simplification are proposed to improve the efficacy of production equipment and processes. Choosing raw materials with molecular structures, similar to the desired chemical building block, will lower the need for heat exchange and make small-scale manufacturing of fuels and chemicals possible.     

Comparative Analysis of Synthetic Natural Gas versus Hydrogen Production from Bagasse

A rigorous and comparative evaluation of two biomass‐to‐gases (BtG) conversion routes was performed and, according to this outcome, it is suggested which of the options evaluated is most desirable. These options, the hydrogen and synthetic natural gas (SNG) production, were designed in Aspen Plus process simulation software. Sugar cane bagasse was considered as feedstock. Mass and energy balance data were extracted from the simulations, and consequently thermodynamic (exergy analysis), economic (financial and uncertainty analysis), and environmental (CO₂ emissions) evaluations were carried out. Exergy and environmental analysis favor the SNG production while the hydrogen route provides higher profits.     

一种多响应性纳米凝胶用于盐酸阿霉素的释放

以甘蔗渣为原料，用HNO3/H3PO4-NaNO2混合体系氧化甘蔗渣纤维素得到单羧基纤维素，然后在交联剂胱胺双丙烯酰胺（CBA）存在下，甲基丙烯酸酐修饰的单羧基甘蔗渣纤维素（MAMC-SBC）和N-异丙基丙烯酰胺（NIPAM）在水相中通过原位自由基共聚反应，得到具有氧化还原、pH和热响应性的纳米凝胶。通过FTIR、1H NMR、SEM和高精度粒度分析仪对纳米凝胶的结构进行表征。结果表明，纳米凝胶是粒径分布均一的微球，在溶胀状态下平均粒度为183± 2 nm。盐酸阿霉素（DOX）作为模型药物被有效地装载到纳米凝胶中，药物载药效率高达82.7 ％。结果发现，通过还原剂、pH和温度及其它们之间的协同效应可以精准地控制药物的释放。     

The effect of air staged, co-combustion of pulverised coal and biomass blends on NOx emissions and combustion efficiency

Co-firing of biomass residues with coal is continuously increasing in it’s application in coal-fired boilers for electricity production. In this study, co-firing experiments were performed using a Russian coal with a range of biomasses, shea meal (SM), cotton stalk (CS), sugarcane bagasse (SB_T), sugarcane bagasse (SB_R) and wood chips (WC) as biomasses in 5%, 10% and 15% thermal fractions to evaluate their potential as substitute fuel and an agent for NO_x control. It was found that the addition of biomass increased NO reduction under both un-staged and air-staged conditions. However, NO reductions obtained under optimum conditions of primary zone stoichiometry (SR₁ = 0.9) and over-fire air (OFA) injection port location 3, were found to be significantly higher than un-staged co-firing for the same biomass thermal share in the fuel blend. It was found that the addition of biomass has a positive effect on carbon burnout under the optimum conditions that were determined in the study. A 10% biomass blending ratio (BBR) was found to be optimum for air-staging conditions. When co-fired under optimum air-staged conditions, a 10% BBR of sugarcane bagasse (SB_R), shea meal (SM), wood chips (WC), cotton stalk (CS) and sugarcane bagasse (SB_T) in coal gave NO reduction of 49%, 51%, 53%, 60% and 72%, respectively.     

以CO2为原料的绿色生物制造

温室气体积累而导致的全球性气候变化引起了人们的广泛重视,因此科学家通过不同的方法在CO₂固定方面进行了诸多的探索与研究,例如化学转化、酶催化及微生物转化等。而微生物的多功能性使得其具有将生物质、生物废物和二氧化碳作为原料来生产生物燃料及化学品等物质的优点。本文对天然存在于微生物体内的、可以固定CO₂的途径进行了一定总结,并主要阐述了利用生物法或生物电化学法等方法将二氧化碳绿色地转化为化学品或生物质能源的相关工作。另外,对以粮食为原料的第一代生物制造以及以非粮食的生物质为原料的第二代生物制造方法及效果进行了评价,同时提出了以CO₂为原料的第三代绿色生物制造的概念。最后预测了在利用二氧化碳进行生物转化的未来发展中所需的关键技术与发展走势。     

Simulation and Exergy Analysis of Recovering Acetaldehyde and Ethanol in 1,3‐Butadiene Production

The production of butadiene from bioethanol as a non‐oil route has become a new research focus. Due to the incomplete conversion of ethanol and acetaldehyde in a single pass it is necessary to recycle the unreacted raw material. On the basis of economic optimization, a new acetaldehyde and ethanol recovery process with optimized operation conditions was developed. The purity of ethanol and acetaldehyde returned to the reactor can be guaranteed. The energy bottleneck of the process was identified by exergy analysis and improved by the proposed thermal integration. Sensitivity analysis was carried out to seek proper parameters for each operation unit. Total utilities cost, energy consumption, and exergy loss in the thermal integrated scheme could be significantly reduced.     

Flowsheet Modeling and Simulation of Biomass Steam Gasification for Hydrogen Production

Hydrogen production from biomass steam gasification is systematically reviewed. Equilibrium modeling and simulation studies using various techniques for effective hydrogen production are presented. Heat integration, economic analysis of the hydrogen production, and systematic design algorithms research publications are overviewed and discussed for energy-efficient and economic hydrogen production from various biomass feedstocks. Comparison and analysis of the results strongly suggest the viable potential of biomass steam gasification for hydrogen production from small to large scales with applications for thermal heat, power generation, and many other industrial fields.     

生物质油与蜡油在FCC装置共炼的多目标优化

生物燃料作为一种可部分代替化石燃料的潜在能源具有绿色、可再生、无硫等优势,但其生产成本一般较高。生物质油与蜡油在催化裂化装置中的共炼通过利用炼厂已有设备可有效降低生物炼厂的投资费用进而降低生物燃料的生产成本。为同时降低共炼过程的经济费用和环境影响以筛选最优的生物质原料和生物质油制备技术,采用Eco-indicator 99方法量化共炼过程的环境影响,提出了针对该过程的多目标优化模型。结果表明:无论是降低经济费用还是减少环境影响,采用催化热解技术制备生物质油优于快速热解;不同目标下所获得的最优生物质原料不同;生物质原料在费用和环境影响中占比最大。因此,在对共炼过程进行优化时,需要考虑过程对环境的影响,而降低生物质原料的消耗对共炼过程费用和环境影响的降低最为有效。     

Restructuring the processes for furfural and xylose production from sugarcane bagasse in a biorefinery concept for ethanol production

This study consisted in restructuring the processes for furfural and xylose production from sugarcane bagasse in a biorefinery concept for the residues utilization on ethanol production.The dilute acid hydrolysis conditions for furfural or xylose production were firstly established on laboratory scale and then reproduced on a 10-L bench reactor fed with direct steam. The furfural production was maximum when using a 1.25% (w/w on dry fiber) H₂SO₄ solution at 175 °C during 40 min; whereas the xylose production attained the best results when using a 1% (w/v) H₂SO₄ solution in a solid/liquid ratio of 1/4 (g/mL), and the sugarcane bagasse impregnated with the acid solution during 24 h prior to the hydrolysis reaction. Enzymatic hydrolysis of the residual solid material obtained from furfural or xylose production was performed with yields of 17.4 and 9.3 g glucose/100 g initial raw material, respectively. Subsequently, ethanol was produced from the residual solid materials obtained from furfural and xylose production with yields of 87.4% and 89.3% respectively, based on the maximum theoretical value (0.51 g ethanol per g glucose in hydrolysate). Such results demonstrated the possibility of restructuring the processes for furfural or xylose production to obtain solid residues able to be used as substrate for ethanol production by fermentation.     

Nitrogen and biofuels; an overview of the current state of knowledge

Biofuels are forms of energy (heat, power, transport fuels or chemicals) based on different kinds of biomass. There is much discussion on the availability of different biomass sources for bioenergy application and on the reduction of greenhouse gas emissions compared to conventional fossil fuels. There is much less discussion on the other effects of biomass such as the acceleration of the nitrogen cycle through increased fertilizer use resulting in losses to the environment and additional emissions of oxidized nitrogen. This paper provides an overview of the state of knowledge on nitrogen and biofuels. Increasing biofuel production touch upon several sustainability issues for which reason sustainability criteria are being developed for biomass use. We propose that these criteria should include the disturbance of the nitrogen cycle for biomass options that require additional fertilizer inputs. Optimization of the nitrogen use efficiency and the development of second generation technologies will help fulfill the sustainability criteria.     

Integrated design of agricultural and industrial processes: A case study of combined sugar and ethanol production

Bioethanol production from molasses has advantages in greenhouse gas emissions because of its energy acquisition from bagasse. However, the improvement of bioethanol productivity is challenging; while each elemental technology option can be greatly improved, the trade‐offs between the production of raw sugar and bioethanol are complex. This issue should be addressed through the optimization of the whole system, including both agricultural and industrial processes. In this study, we constructed a model of combined raw sugar and bioethanol production from sugarcane considering agricultural and industrial technology options. Data were acquired through a detailed investigation of actual sugar mills. Case studies on the redesign of combined raw sugar and bioethanol production demonstrated that the simultaneous implementation of both technology options increases production of food, materials, and energy from plant‐derived renewable resources, thus demonstrating the effectiveness of the interdisciplinary approach. © 2016 American Institute of Chemical Engineers AIChE J, 63: 560–581, 2017     

Preliminary Studies on Furfural Production from Lignocellulosics

This study focused on the production of furfural from agricultural and industrial biomass residues by a hydrodistillation process. Corncobs, sugarcane bagasse, and eucalypt wood were treated with sulfuric, hydrochloric, and phosphoric acids as catalysts, with different acid concentrations (1.5 to 5.2 mol.L ^?1). In addition, the eucalypt liquor from the auto-hydrolysis, kraft-dissolving pulp production process was also investigated as a source of furfural, using sulfuric and hydrochloric acids as a catalyst (0.9 and 3.9 mol.L ^?1) . Furfural yields of 30.2, 25.8, and 13.9% were achieved for corncob, sugarcane bagasse, and eucalypt wood, respectively, on the basis of biomass dry weight. The efficiency of conversion from pentose to furfural using eucalypt liquor from the auto-hydrolysis kraft process was 71.5% using HCl 3.9 mol.L ^?1 . Due to the presence of a high amount of pentose, corncob produced the highest amount of furfural, followed by sugarcane bagasse and then eucalypt wood.