Economic analysis of two processes for biodiesel production

In this study, two continuous processes for biodiesel production, alkali catalyzed process and solid acid catalyzed process, are discussed with the help of Aspen Plus. By comparing some economic indicators, it can be found that solid acid catalysis could be a good choice for investors in the near future.     

Evaluation of hydrogen producing cultures using pretreated food waste

In order to enhance bio-hydrogen production from food waste, pretreatment methods are widely used. The influence of the initial pH and autoclaving were investigated in batch experiments. Fermentative studies showed that pure cultures like Clostridium beijerinckii could directly utilize raw food waste to produce hydrogen, while other cultures (Clostridium butyricum and Clostridium pasteurianum) could produce hydrogen only after pH adjustment. In this case, the optimal starting pH of the culture was found to be 7. Autoclaving could further enhance hydrogen yields due to increased hydrolysis of food waste. The maximum hydrogen yield was achieved by C. butyricum (38.9 mL-H₂/g-VS_added) after autoclaving food waste with pH adjustment at 7. In addition, the ratio acetic to butyric acid was decreased by autoclaving pretreatment, because butyrate metabolic pathway was favored in the fermentation process. However, suitable pH for bacteria growth and the low ammonia production could be achieved from autoclaving food waste.     

液-固流化床回收废旧印刷电路板金属研究

采用液-固流化床对废旧印刷电路板资源化利用进行研究,通过分析颗粒在流化床中的运动机理,计算不同颗粒在流化床中的沉降末速度,并探讨影响颗粒沉降末速度的因素。结果表明,颗粒干扰沉降末速度随着颗粒密度和粒度的增大而增大,随着颗粒体积分数的增大而减小;对不同粒级不同给料量进行分选,随着上升水速的增大,金属回收率随之下降,品位随之提高;在实验范围内,给料量对液-固流化床中金属与非金属的分选效果基本无影响。     

Preparation of chitosan-based flocculant for high density waste drilling mud solid–liquid separation

High performance flocculant was prepared by chitosan (CS), ethacryloyloxyethyl trimethyl ammonium chloride (DMC), and acrylamide (AM). The optimum preparation conditions were determined by orthogonal test of four factors and three levels. The different factors affecting the flocculating ability of the prepared flocculants for waste drilling mud were studied, and optimal synthesis conditions were established: polymerization temperature was 60, reaction time was 4 h, DMC was 3 mL, w(AM) : w(CS) was 4, and the initiator was 0.4% of AM (wt %). The prepared CS–AM–DMC copolymer was characterized by Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), and gel permeation chromatography (GPC). The results showed that AM, DMC were grafted to CS successfully. The solid–liquid separation properties were also investigated, and the prepared flocculant showed great advantages than commercial products for high density waste drilling mud use. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A review of bio-oils from waste biomass: Focus on fish processing waste

Biofuels are derived from biomass using biochemical, thermochemical, and physical and chemical extraction processes. Waste oils from animal and vegetable sources continue to be important biomass feedstock due to the potential benefits over petroleum and some of the virgin vegetable oil based fuels. In this paper, the chemical, thermal, and physical properties of biofuels derived from virgin and waste sources are reviewed. In addition, the processes used for recovering bio-oils from animal fats (beef tallow, lard, and poultry waste) and greases, and purification and refining of bio-oils are discussed as well as the resulting performance as a fuel. Particular focus will be on production of biofuels from fish waste. The potential for biofuel from fish waste is a function of the location and size of the processing plant, type of fuel requirements, and characteristics of the fish waste.     

角质酶/表面活性剂体系对混合办公废纸的协同脱墨作用

角质酶能够水解可溶性酯、不溶性甘油三酯和各种聚酯，因此可以水解油墨中的连接料，有代替脂肪酶应用于废纸脱墨领域的潜能。利用角质酶和实验室复配得到的表面活性剂协同应用于混合办公废纸脱墨领域，探讨其脱墨效果和最优工艺，并与常用商业脂肪酶进行脱墨效果比较。结果表明，角质酶在酶用量10 U·g^-1，酶处理时间30 min，酶处理温度50℃，表面活性剂用量0.2%的条件下可以达到最优效果。与脂肪酶/表面活性剂以及单独用表面活性剂脱墨相比，角质酶脱墨后纸页的白度与油墨去除率更高，纸页的机械强度也较好。通过纸页性能的对比和扫描电镜（SEM）观察，角质酶的脱墨效果较脂肪酶更佳，角质酶/表面活性剂体系对混合办公废纸脱墨效果较好。     

变负荷机组锅炉经济连续排污流量的确定

通过开展变负荷机组的热化学实验，监督不同负荷工况下的汽水品质，确定较为经济的锅炉连续排污流量，对产生的效益进行了分析和计算。     

城市固体废弃物治理的应用探讨

对我国城市固体废弃物及其污染现状进行了概述和分析,结合实际情况探讨了有效的治理措施及应用。