生物质发电工程的环保设计

简要介绍生物质发电工程环保设计的重点,确保环保达标;并总结工程设计中遇到的常见问题,给出优化设计结果,以促进生物质发电工程的不断发展。     

Influence of biomass density and food to microorganisms ratio on the mixed culture type I methanotrophs enriched from activated sludge

Methanotrophic based process can be the remedy to offset the wastewater treatment facilities increasing energy requirements due to methanotroph's unique ability to integrate methane assimilation with multiple biotechnological applications like biological nitrogen removal and methanol production. Regardless of the methanotrophic process end product, the challenge to maintain stable microbial growth in the methanotrophs cultivation bioreactor at higher cell densities is one of the major obstacles facing the process upscaling. Therefore, a series of consecutive batch tests were performed to attentively investigate the biomass density influence on type I methanotrophs bacterial growth. In addition, food to microorganisms(F/M), carbon to nitrogen(C/N) and nitrogen to microorganisms(N/M) ratio effect on the microbial activity was studied for the first time. It was clarified that the F/M ratio is the most influencing factor on the microbial growth at higher biomass densities rather than the biomass density increase, whereas C/N and N/M ratio change, while using nitrate as the nitrogen source,does not influence methanotrophs microbial growth. These study results would facilitate the scaling up of methanotrophic based biotechnology by identifying that F/M ratio as the key parameter that influences methanotrophs cultivation at high biomass densities.     

大空间建筑防排烟系统性能化设计

为了获得合理有效的大空间建筑排烟系统设计方案,从排烟方式的选择、排烟量(排烟面积)的确定以及烟控系统排烟的效果评估和验证三个方面对大空间建筑防排烟系统的性能化设计进行了探讨,并指出:建筑防排烟系统的选择及其排烟量(排烟面积)的确定应结合建筑功能特点、可燃物分布、安全性能目标、补气条件、环境条件等进行综合考虑并进行核算;在条件允许情况下,应尽量采用数值模拟计算、模型试验以及开展实地场所的热烟测试进行防排烟系统的效果验证。本研究结果可为大空间建筑防排烟系统的合理性设计提供参考。     

锅炉烟气排放系统环保设计的主要参数及计算

根据高斯扩散模式论述了污染物净化效率、烟囱几何高度和烟气抬升高度是锅炉烟气排放系统环保设计的主要参数，并介绍了这三个参数的计算方法。     

燃气替代燃煤对改善兰州市空气质量的分析

通过对兰州市自然环境条件的介绍,分析了兰州市大气污染主要是由于燃煤造成的.天然气作为一种清洁能源,能够减少燃煤造成的大气污染.通过燃气替代燃煤,可以减少污染物的排放,改善兰州市空气质量状况.运用环境经济政策的理论,分析了"煤改气"的可行性.     

高层建筑火灾时走廊-前室缓冲区效果数值模拟研究

高层建筑火灾时,正压防烟带入的大量新鲜空气被送入着火层并稀释了烟气,降低了机械排烟效率.提出设置高层建筑条形走廊-前室缓冲区的设想,采用双方程κ-ε模型,对设置缓冲区后排烟效果的影响进行了模拟和分析.结果表明:建有前室缓冲区后,前室内烟气的平均质量分数远小于4.6％,前室在较长时间内处于安全状态.从走廊扩散至竖井的烟气分别经过走廊、前室两次降温,温度下降明显,在竖井中容易形成滞止状态,使其向上方其他楼层扩散的趋势降低,对整栋楼内人员疏散而言更为有利.     

长廊型建筑前室缓冲区对排烟效果的影响

高层建筑发生火灾时,采用加压防烟将会有大量的新鲜空气被送入着火层。这些新鲜空气稀释了烟气,从而降低了机械排烟效率。提出了高层建筑条形走廊前室缓冲区的设想,并通过高层建筑内烟气流动的数学模型,采用双方程三维紊流模型,对相同排烟量情况下前室缓冲区对排烟效果的影响进行了模拟计算和对比分析。结果表明：对条形走廊,前室缓冲区能够提高机械排烟效率近3.6%,同时在前室门附近走廊内形成一段相对安全的区域,有利于人员逃离着火层。     

Pyrolysis Investigation For Bio-Oil Production From Various Biomass Feedstocks In Thailand

This study investigated the bio-oil production from vacuum pyrolysis of potential biomass feedstocks in Thailand. Experiments were carried out on palm empty fruit bunch, rice straw, rice husk, eucalyptus wood, rubber wood (Hevea Brasiliensis), and Teng wood (Shorea Obtuse) in a lab-scale-fixed bed reactor. The results showed that the product distribution was strongly dependent on temperature and biomass properties. Maximum oil yields, i.e., 50–60 wt %, were reached at 450–550°C. Due to mild temperature, most of alkalis originally present in biomass concentrated in product char, and only traces were detected in oil. Two-third of energy in biomass was in the product oil.     

Individual particle analysis of aerosols collected at Lhasa City in the Tibetan Plateau

To understand the composition and major sources of aerosol particles in Lhasa City on the Tibetan Plateau (TP), individual particles were collected from 2 February to 8 March, 2013 in Tibet University. The mean concentrations of both PM_2.5 and PM₁₀ during the sampling were 25.7 ± 21.7 and 57.2 ± 46.7 μg/m³, respectively, much lower than those of other cities in East and South Asia, but higher than those in the remote region in TP like Nam Co, indicating minor urban pollution. Combining the observations with the meteorological parameters and back trajectory analysis, it was concluded that local sources controlled the pollution during the sampling. Transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectra (EDS) was used to study 408 particles sampled on four days. Based on the EDS analysis, a total of 8 different particle categories were classified for all 408 particles, including Si-rich, Ca-rich, soot, K-rich, Fe-rich, Pb-rich, Al-rich and other particles. The dominant elements were Si, Al and Ca, which were mainly attributed to mineral dust in the earth's crust such as feldspar and clay. Fe-, Pb-, K-, Al-rich particles and soot mainly originated from anthropogenic sources like firework combustion and biomass burning during the sampling. During the sampling, the pollution mainly came from mineral dust, while the celebration ceremony and religious ritual produced a large quantity of anthropogenic metal-bearing particles on 9 and 25 February 2013. Cement particles also had a minor influence. The data obtained in this study can be useful for developing pollution control strategies.     

香烟水溶性提取物对大鼠心肌线粒体的毒性

观察香烟水溶性提取物(CSE)和尼古丁对大鼠心肌线粒体的损伤作用.大鼠心肌线粒体分别与CSE或尼古丁于37℃温孵60min,结果表明,CSE明显降低线粒体细胞色素C氧化酶(COX)活性,呈剂量依赖性.但是ATPase活性不受影响.在线粒体呼吸活性受到抑制的同时,过氧化指标无明显变化.CSE对6.5mmol/L钙离子引起的线粒体肿胀反应具有抑制作用,但可加剧250mmol/L钙离子诱导的线粒体肿胀反应.维生素C对CSE造成的线粒体损伤无保护作用.未见尼古丁对体外大鼠心肌线粒体有毒性.CSE对心肌线粒体的损伤可能是由于它对呼吸酶活性的直接抑制作用而与氧自由基机制无关.尼古丁可能不是CSE损伤大鼠心肌线粒体的毒性成分.