A novel fed-batch digestion system for biomethanation of plant biomasses

Plant biomasses, which in the absence of adequate pretreatment pose serious operational problems in biogas production using conventional domestic flow-through digesters, can be successfully digested in a novel fedbatch digestion system that produces a steady rate of biogas. Basically, the system is a batch digestion operated with a regular input of a calculated amount of feed based on first order decay kinetics in order to maintain a regular biogas production rate. For nearly three years the system was tested in a laboratory-scale fed-batch digester (10 l) using dried water hyacinth as feed providing the desired biogas production rate. A field-scale domestic digester of masonry construction with a working volume of 10 m3 was designed and tested for about 9 months by feeding a mixture of dried water hyacinth or banana stem along with sugarcane press mud, yielding an average biogas production of 90-100% of the expected rate calculated on the basis of the feed rate.     

Removal of 3-chlorobenzoate using granules in the upflow anaerobic sludge blanket method

The possibility of removing 3-chlorobenzoate from water using granules in the upflow anaerobic sludge blanket (UASB) method without the addition of a dechlorinating culture was studied on a laboratory scale. After three months of operation, the 3-chlorobenzoate concentration in the effluent decreased to less than 1 mg.l(-1).     

Potential restrictions for CO2 sequestration sites due to shale and tight gas production

Carbon capture and geological sequestration is the only available technology that both allows continued use of fossil fuels in the power sector and reduces significantly the associated CO(2) emissions. Geological sequestration requires a deep permeable geological formation into which captured CO(2)can be injected, and an overlying impermeable formation, called a caprock, that keeps the buoyant CO(2) within the injection formation. Shale formations typically have very low permeability and are considered to be good caprock formations. Production of natural gas from shale and other tight formations involves fracturing the shale with the explicit objective to greatly increase the permeability of the shale. As such, shale gas production is in direct conflict with the use of shale formations as a caprock barrier to CO(2) migration. We have examined the locations in the United States where deep saline aquifers, suitable for CO(2) sequestration, exist, as well as the locations of gas production from shale and other tight formations. While estimated sequestration capacity for CO(2) sequestration in deep saline aquifers is large, up to 80% of that capacity has areal overlap with potential shale-gas production regions and, therefore, could be adversely affected by shale and tight gas production. Analysis of stationary sources of CO(2) shows a similar effect: about two-thirds of the total emissions from these sources are located within 20 miles of a deep saline aquifer, but shale and tight gas production could affect up to 85% of these sources. These analyses indicate that colocation of deep saline aquifers with shale and tight gas production could significantly affect the sequestration capacity for CCS operations. This suggests that a more comprehensive management strategy for subsurface resource utilization should be developed.     

银冬颗粒的质量标准研究

目的:建立银冬颗粒的质量标准。方法:采用HPLC测定银冬颗粒中绿原酸的含量,紫外分光光度法测定总黄酮的含量,并按药典进行相应的制剂学性质考察。结果:绿原酸含量为11.4029 mg.g-1,总黄酮的含量为44.2101 mg.g-1,银冬颗粒性状、粒度、水分、溶解性、装量差异均符合中国药典的要求。结论:银冬颗粒的质量标准稳定、可行,评价指标合理、可靠。     

Effects of microwave-discharged cold plasma on synthesis and characteristics of citrate derivatives of corn starch granules

The objectives of this study were to identify the potential function of microwave-discharged cold plasma (MCP) treatment in preparing starch citrate (SC) non-thermally and to investigate the physicochemical properties of MCP-induced starch citrates. SCs were prepared by either dry heating in a convection oven (as a reaction control; COV) or MCP treatment using N₂ (N₂-MCP) and N₂–O₂ (N₂/O₂-MCP). Fourier transform-infrared spectra of the MCP-induced SCs revealed new peaks indicating ester bonds. The molar degree of substation was 0.013–0.015 depending on the reaction conditions. The plasma-formed dents were observed more on the surfaces of granular starch citrates (GSCs) treated with N₂/O₂-MCP than N₂-MCP. Relative to COV, MCP-induced GSCs possessed lower resistant starch content, solubility, and gelatinization temperatures and higher swelling power. The pasting viscosities were higher with N₂-MCP GSCs and lower with N₂/O₂-MCP GSCs. The results suggest that MCP can be used as a novel catalyst for non-thermal starch citration.     

Effects of pH on ex-situ biomethanation with hydrogenotrophic methanogens under thermophilic and extreme-thermophilic conditions

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The influence of carbon dioxide on gas exchange of mungbean sprouts at aerobic and anaerobic conditions

Gas-exchange models are often used to predict gas conditions inside modified atmosphere (MA) packages of fresh plant products. Current models describing CO₂ production of harvested plant products do not account for an inhibition of a high partial pressure of CO₂ on fermentation rates, whereas such as inhibition on plant metabolism is often found. An existing gas-exchange model was modified to include this inhibition. Gas-exchange data of mungbean sprouts were collected under various partial pressures of O₂ and CO₂ and used to validate the model. With the modification applied, CO₂ production rates were better described. Although CO₂ production at low O₂ was reduced by high partial pressures of CO₂, no influence was found on ethanol and acetaldehyde levels. The data found also indicate large differences between gas-exchange rates of different batches of mungbean sprouts. It is suggested that microbial metabolism attributes substantially to total CO₂ production rates found and that it might explain these differences. © 1998 SCI.     

菜籽生物柴油合成反应程度的气相色谱法判断

以十三酸甲酯为内标,建立了菜籽生物柴油中主要脂肪酸甲酯的气相色谱测定法。进样中各脂肪酸甲酯含量在各自线性范围内的线性相关系数r≥0.9963、平均回收率在97.59%~101.42%、相对标准偏差在1.32%~2.89%。通过测定反应试样中的脂肪酸甲酯总量,再与原料油脂完全甲酯化产品中的甲酯总量相比较,可以准确地判断生物柴油合成反应程度。     

Greenhouse gas emission reductions from domestic anaerobic digesters linked with sustainable sanitation in rural China

Anaerobic digesters provide clean, renewable energy (biogas) by converting organic waste to methane, and are a key part of China's comprehensive rural energy plan. Here, experimental and modeling results are used to quantify the net greenhouse gas (GHG) reduction from substituting a household anaerobic digester for traditional energy sources in Sichuan, China. Tunable diode laser absorption spectroscopy and radial plume mapping were used to estimate the mass flux of fugitive methane emissions from active digesters. Using household energy budgets, the net improvement in GHG emissions associated with biogas installation was estimated using global warming commitment (GWC) as a consolidated measure of the warming effects of GHG emissions from cooking. In all scenarios biogas households had lower GWC than nonbiogas households, by as much as 54%. Even biogas households with methane leakage exhibited lower GWC than nonbiogas households, by as much as 48%. Based only on the averted GHG emissions over 10 years, the monetary value of a biogas installation was conservatively estimated at US$28.30 ($16.07 ton(-1) CO(2)-eq), which is available to partly offset construction costs. The interaction of biogas installation programs with policies supporting improved stoves, renewable harvesting of biomass, and energy interventions with substantial health cobenefits are discussed.     

水热法合成氧化锌亚微米棒及气敏性能研究

以分析纯试剂ZnSO4·7H2O为原料,添加表面活性剂十六烷基三甲基溴化铵(CTAB), 采用水热方法制备氧化锌亚微米棒.运用X射线衍射仪(XRD)、透射电镜(TEM)等对合成产物的结构、形貌进行表征,采用静态配气法进行气敏特性测试.结果表明,ZnO亚微米棒的直径约200 nm,长度约3 μm;用亚微米棒制作的气敏元件对酒精和汽油具有较高的灵敏度.     

紫薯颗粒全粉加工工艺优化

用鲜紫薯山川紫为原料,以碘蓝值和感官评分为评价指标,采用单因素试验法和Box-Behnken试验设计对紫薯颗粒全粉加工工艺参数进行优化.结果表明:蒸煮时间9 min,浸钙浓度37.5 μg/mg,干燥温度61℃,筛分粒度100目所制得的紫薯颗粒全粉感官评分最高,细胞破碎度最小.     

甘薯全粉研究进展

甘薯全粉是近年新兴甘薯产品,我国甘薯资源丰富,较适合在我国进行规模生产。该文分析甘薯全粉概念,介绍甘薯全粉生产工艺、品质特性及在食品加工中应用,并展望我国甘薯全粉市场前景,指出发展甘薯全粉加工有利于推动我国甘薯产业良性发展。     

Evaluation of low density hybrid panels using expandable granules: effect of granules diameter and content

Low density hybrid panels (16 mm thickness) were produced using wood fiber as face layers and a mixture of coarse wood particles and expandable polystyrene (EPS) as core layer. The EPS was foamed (in-situ foaming) in the core layer during the pressing stage. The effects of granules diameter (0.4, 0.8, 1.15, 1.5, and 2.2 mm) and granules content (5, 10, and 15%) on the physical and mechanical properties were evaluated. The results showed that both variables had significantly influenced the panels’ properties. Mechanical properties mostly depended on the level of mechanical inter-locking of EPS with wood particles, while the physical properties were mostly influenced by the EPS distribution. Stronger mechanical inter-locking of EPS with wood particles was achieved by both larger diameter and higher amount of EPS granules (2.2 mm and 15%). A better EPS distribution between the wood particles was observed with the smaller EPS granules and higher amount of EPS (0.4 mm and 15%).     

Pathways for the anaerobic microbial debromination of polybrominated diphenyl ethers

The debromination pathways of seven polybrominated diphenyl ethers (PBDEs) by three different cultures of anaerobic dehalogenating bacteria were investigated using comprehensive two-dimensional gas chromatography (GC x GC). The congeners analyzed were the five major components of the industrially used octa-BDE mixture (octa-BDEs 196, 203, and 197, hepta-BDE 183, and hexa-BDE 153) as well as the two most commonly detected PBDEs in the environment, penta-BDE 99 and tetra-BDE 47. Among the dehalogenating cultures evaluated in this study were a trichloroethene-enriched consortium containing multiple Dehalococcoides species, and two pure cultures, Dehalobacter restrictus PER-K23 and Desulfitobacterium hafniense PCP-1. PBDE samples were analyzed by GC x GC coupled to an electron capture detector to maximize separation and identification of the product congeners. All studied congeners were debrominated to some extent by the three cultures and all exhibited similar debromination pathways with preferential removal of para and meta bromines. Debromination of the highly brominated congeners was extremely slow, with usually less than 10% of nM concentrations of PBDEs transformed after three months. In contrast, debromination of the lesser brominated congeners, such as penta 99 and tetra 47, was faster, with some cultures completely debrominating nM levels of tetra 47 within weeks.     

葛根全粉茶的加工工艺

研究了一种用葛根全粉制作葛根茶的加工工艺,通过对水添加量、食用胶选择和用量、焙烤和提香条件进行研究,确定了适宜的工艺条件。实验结果表明,水添加量为粉料的45%,卡拉胶与魔芋胶的总添加量为0.5%(以葛根全粉计),比例为4∶2,170℃下焙烤6min,120℃下提香15min为适宜的工艺条件。制得的葛根茶具有良好的感官品质,感官评分达97分,且易实现工业化生产。     

两相厌氧工艺在制糖废水处理中的应用

由于两相厌氧工艺具有产酸相与产甲烷相分离的特性,因此在处理具有高有机负荷、高悬浮物浓度（SS）的制糖废水方面具有独特的优势。针对制糖废水的特征、传统的治理技术进行了论述,并对两相厌氧工艺在处理制糖废水方面所存在的独特优势进行了分析。     

英国二次纤维的资源研究

一项受废品和资源行动方案（WRAP）委托、由?F－QPS和NLK联合公司实施的研究旨在确立英国纸和纸板工业为西欧二次纤维最大用户之一的地位。利用更多的二次纤维是很有潜力的，但实现怎样的目标是开展此项研究最中心的议题。进一步的研究是将英国与其他西欧各国在废纸回收方面进行评价。英国造纸工业和WRAP在该项目中进行的密切合作和卓有成效的工作是值得重视的，项目行动小组对此表示感谢。该研究是基于对英国８６家造纸厂中的７６家进行的综合调查。研究结果显示，英国纸和纸板生产能力的大幅度提高是大量使用二次纤维的唯一原因。同…     

Quinoa starch granules: a candidate for stabilising food-grade Pickering emulsions

BACKGROUND: Particle‐stabilised emulsions, so‐called Pickering emulsions, are known to possess many beneficial properties, including being extremely stable. Starch granules isolated from quinoa have been used as emulsion stabilising particles. The granules were intact, 1–3 µm in diameter and modified with octenyl succinic anhydride to increase their hydrophobicity. Starch granules, as opposed to most other particles used to generate Pickering emulsions, are edible, abundant and derived from natural sources. RESULTS: Emulsions produced by high shear homogenisation had droplet sizes of 9–70 µm depending on the starch‐to‐oil ratio. Droplet size decreased with increasing starch‐to‐oil ratio, but was unaffected by the oil phase volume over a range of 5–33% oil (v/v). Although the drops were large and subject to creaming, their size remained unchanged over a period of 7 days. By adjusting the starch‐to‐oil ratio drops could be made to be buoyancy neutral to prevent creaming. Rheological characterisation indicated a gel structure with an elastic modulus in the range 200–2000 Pa depending on droplet size. CONCLUSION: This work has demonstrated the successful use of starch granules to stabilise emulsions which may find applications beyond that of food, for example in cosmetics and pharmaceutical formulations. Copyright © 2012 Society of Chemical Industry