热烟气气氛下生物质在流化床反应器中快速热解制取生物油（英文）

在对操作流化速度进行冷态实验以及流化床温度稳定性进行测试的基础上,研制了新型流化床反应器,并使用玉米秸秆为原料,探究了热烟气气氛下快速热解制取生物油的最佳反应温度以及床料。在最佳热解条件下,对糠醛废弃物、木糖废弃物以及海藻进行了实验研究,得到了各产物产率,并对得到的生物油进行了物理特性分析。结果显示,在最佳操作流速下,当温度为500℃时使用白云石为床料可以获得最大生物油产率。4种原料中玉米秸秆的生物油产率最高,达到42.3 wt%。在最佳热解条件下获得了4种物料不同含量的重油和轻质油,其中重油的物理特性差别很小,重油的热值比轻质油的热值高很多。不可冷凝气的高位热值是6.5-8.5 MJ/m3,因此不可冷凝气体可以作为一种燃料气被加以利用。     

巢湖蓝藻与农业废弃物共热解制取生物质油研究

采用蔗渣、玉米秸秆和棉花秸秆3种废弃物与蓝藻进行混合共热解试验,考察废弃物的加入对蓝藻热解液体产率及组分的影响。结果表明:添加3种废弃物均使共热解液体产率呈下降趋势。当蓝藻与废弃物以1∶1混合共热解时,以蓝藻和玉米秸秆共热解液体产率最高,为61.8%,且除苯酚类以外,液体产物组分与单一蓝藻热解产物组分相近,含氮化合物含量明显降低,相对含量由18.49%降至8.15%。与其它2种废弃物相比,蓝藻与玉米秸秆在适当比例下的共热解有利于改善热解油品质。     

熔盐热裂解生物质制生物油

为探讨热裂解条件对熔盐中生物质热裂解制生物油的影响,在自行设计的反应器中,以摩尔比为7∶6的ZnCl2-KCl混合熔盐作为热裂解的热载体、催化剂和分散剂,考察了500 ℃时添加的金属盐和生物质原料的影响,并采用气相色谱-质谱仪 (GC-MS) 对生物油的主要组成进行了分析。结果表明：添加的金属盐显著影响热裂解产物得率,稀土金属盐显著提高生物油得率,降低生物油的含水率,添加摩尔分数为5.0％ LaCl3时生物油得率为32.0％,含水率为61.5％;水稻秸秆热裂解的生物油和焦炭得率较高,稻壳热裂解的气体得率较高;金属添加盐对生物油组成有较强的选择性,LiCl和FeCl2对生物质向小分子裂解具有较强的催化作用,而CrCl3、CaCl2和LaCl3对生物油二次裂解具有抑制作用。研究结果为熔盐热裂解生物质制生物油提供了参考。     

以油体作为生物反应器的研究进展

获得安全、经济、稳定具有生物活性的重组蛋白,应用于基础研究及临床应用是一个重大的战略课题,现在可以利用酵母、细菌和动物细胞生产多种药物蛋白,但这些蛋白的生产过程还存在许多问题.利用植物作为生物反应器生产药用蛋白和疫苗是目前生物反应器研究的热点.油体蛋白在油料作物种子中高水平表达且易于分离,经过改造后是生产目的蛋白的一种理想栽体.介绍了油体、油体蛋白的结构以及利用植物油体蛋白表达体系这一新型植物生物反应器生产目的蛋白的研究进展和前景.     

生物造粒流化床污水处理反应器中微生物的分布特征

对生物造粒流化床污水处理反应器10cm、60cm、110cm处好氧细菌总数以及反硝化菌、反硫化菌分别进行计数,同时,用光学显微镜、扫描电子显微镜以及石蜡切片技术对粒状污泥中细菌的分布情况进行研究。结果发现,流化床中好氧细菌非常丰富,在反应器10cm处,每克污泥微生物的数量可达1.6×10⁸个,说明好氧细菌在生物造粒流化床有机物生物降解中起主导作用;同时,流化床中也有一定数量的兼性厌氧菌存在,并且随着流化床床体的升高有增加的趋势,这与溶解氧(DO)随流化床床体高度的增加而迅速降低有关;随着回流比的增加,溶解氧增高,相应的好氧细菌有所增加而兼性厌氧菌减少;对于颗粒污泥,其表面和内部微生物分布数量有很大的差异。     

喜热噬油芽胞杆菌产生的生物乳化剂的组成与性质

由喜热噬油芽胞杆菌(Geobacillus thermoleovorans str 5366T)以正十六烷为碳源 55 ℃培养的发酵液中分离获得了一种生物乳化剂,经鉴定为糖-肽-脂复合物.该乳化剂中糖、肽、脂和烃的含量分别为29.4%、15.8%和35.8%.利用肽水解结合氨基酸分析、糖醇乙酰化结合GC-MS、脂肪酸甲脂化结合GC-MS等技术手段鉴定乳化剂中糖主要为D-甘露糖;主要氨基酸为谷氨酸、天冬氨酸、丙氨酸;构成脂的主要脂肪酸为十六烷酸、十八烯酸和十八烷酸.该菌及其代谢产生的乳化剂乳化性能良好,具有高温条件下应用的潜力.     

对—氯代苯胺（PCA）在填充床生物反应器中的降解作用

以氯代苯胺（ＰＣＡ）为选择基质,用驯化技术从降解对二氯苯（ｐＤＣＢ）的富集培养物中得到了以同化ＰＣＡ为唯一碳源和氮源的混合微生物．将这种固定在填充床反应器中的微生物用于ＰＣＡ的降解作用研究中．在该反应器里,ＰＣＡ的生物降解遵循Ｌｏｇｉｓｔｉｃ方程ｑ＝ｑｍａｘ／（１＋ｅα－βＵｖ）．由方程求出了主要的动力学常数,Ｋｓ（半速率常数）和ｑｍａｘ（最大比基质降解速率）．于ＰＣＡ降解的同时,释放氯离子到培养基中．在水力停留时间３ｈ,进水ＰＣＡ浓度为３６０ｍｇ·Ｌ－１情况下,基质的体积降解率达到１２５ｍｇ·Ｌ－１·ｈ－１;基质的百分去除率为９１％．     

对-氯代苯胺(PCA)在填充床生物反应器中的降解作用

以氯代苯胺(PCA)为选择基质,用驯化技术从降解对二氯苯(p-DCB)的富集培养物中得到了以同化PCA为唯一碳源和氮源的混合微生物。将这种固定在填充床反应器中的微生物用于PCA的降解作用研究中。在该反应器里,PCA的生物降解遵循Logistic方程q=q_max/(1+e^α-βU_v).由方程求出了主要的动力学常数,K_s(半速率常数)和q_max(最大比基质降解速率).于PCA降解的同时,释放氯离子到培养基中。在水力停留时间3h, 进水PCA浓度为360mg·L^-1情况下,基质的体积降解率达到125mg·L^-1·h^-1;基质的百分去除率为91%.     

皱皮油丹(樟科)在云南东南部的发现及其生物地理学意义

该文报道了在云南省马关县古林箐省级自然保护区发现的一个云南省新记录种——皱皮油丹(Alseodaphne rugosa Merr.et Chun),并对其形态、生境及该新记录种的生物地理学意义进行了描述与讨论。此新记录种的发现对樟科油丹属植物的系统分类学、生物地理学和区域生物多样性等方面的研究具有重要意义,同时也为探讨海南岛的起源问题提供了具有价值的研究材料。     

Jute stick pyrolysis for bio-oil production in fluidized bed reactor

Pyrolysis of jute stick for bio-oil production has been investigated in a continuous feeding fluidized bed reactor at different temperatures ranging from 300 degrees C to 600 degrees C. At 500 degrees C, the yields of bio-oil, char and non-condensable gas were 66.70 wt%, 22.60 wt% and 10.70 wt%, respectively based on jute stick. The carbon based non-condensable gas was the mixture of carbon monoxide, carbon dioxide, methane, ethane, ethene, propane and propene. The density and viscosity of bio-oil were found to be 1.11 g/mL and 2.34 cP, respectively. The lower heating value (LHV) of bio-oil was found to be 18.2 5 MJ/kg. Since bio-oil contains some organic acids such as formic acid, acetic acid, etc., the pH and acid value of the bio-oil were found to be around 4 and 135 mg KOH/g, respectively. The water, lignin, solid and ash contents of bio-oil were determined and found to be around 15 wt%, 4.90 wt%, 0.02 wt% and 0.10 wt%, respectively.     

Biomass fast pyrolysis in a fluidized bed reactor under N2, CO2, CO, CH4 and H2 atmospheres

Biomass fast pyrolysis is one of the most promising technologies for biomass utilization. In order to increase its economic potential, pyrolysis gas is usually recycled to serve as carrier gas. In this study, biomass fast pyrolysis was carried out in a fluidized bed reactor using various main pyrolysis gas components, namely N₂, CO₂, CO, CH₄ and H₂, as carrier gases. The atmosphere effects on product yields and oil fraction compositions were investigated. Results show that CO atmosphere gave the lowest liquid yield (49.6%) compared to highest 58.7% obtained with CH₄. CO and H₂ atmospheres converted more oxygen into CO₂ and H₂O, respectively. GC/MS analysis of the liquid products shows that CO and CO₂ atmospheres produced less methoxy-containing compounds and more monofunctional phenols. The higher heating value of the obtained bio-oil under N₂ atmosphere is only 17.8 MJ/kg, while that under CO and H₂ atmospheres increased to 23.7 and 24.4 MJ/kg, respectively.     

Optimization of a free-fall reactor for the production of fast pyrolysis bio-oil

A central composite design of experiments was performed to optimize a free-fall reactor for the production of bio-oil from red oak biomass. The effects of four experimental variables including heater set-point temperature, biomass particle size, sweep gas flow rate and biomass feed rate were studied. Heater set-point temperature ranged from 450 to 650 °C, average biomass particle size from 200 to 600 μm, sweep gas flow rate from 1 to 5 sL/min and biomass feed rate from 1 to 2 kg/h. Optimal operating conditions yielding over 70 wt.% bio-oil were identified at a heater set-point temperature of 575 °C, while feeding red oak biomass sized less than 300 μm at 2 kg/h into the 0.021 m diameter, 1.8 m tall reactor. Sweep gas flow rate did not have significant effect on bio-oil yield over the range tested.     

Effect of hot vapor filtration on the characterization of bio-oil from rice husks with fast pyrolysis in a fluidized-bed reactor

To produce high quality bio-oil from biomass using fast pyrolysis, rice husks were pyrolyzed in a 1-5 kg/h bench-scale fluidized-bed reactor. The effect of hot vapor filtration (HVF) was investigated to filter the solid particles and bio-char. The results showed that the total bio-oil yield decreased from 41.7% to 39.5% by weight and the bio-oil had a higher water content, higher pH, and lower alkali metal content when using HVF. One hundred and twelve different chemical compounds were detected by gas chromatography-mass spectrometry (GC-MS). The molecular weight of the chemical compounds from the condenser and the EP when the cyclone was coupled with HVF in the separation system decreased compared with those from the condenser and EP when only cyclone was used.     

Comparison of non-catalytic and catalytic fast pyrolysis of corncob in a fluidized bed reactor

Fast pyrolysis of corncob with and without catalyst was investigated in a fluidized bed to determine the effects of pyrolysis parameters (temperature, gas flow rate, static bed height and particle size) and a HZSM-5 zeolite catalyst on the product yields and the qualities of the liquid products. The result showed that the optimal conditions for liquid yield (56.8%) were a pyrolysis temperature of 550 degrees C, gas flow rate of 3.4 L/min, static bed height of 10 cm and particle size of 1.0-2.0mm. The presence of the catalyst increased the yields of non-condensable gas, water and coke, while decreased the liquid and char yields. The elemental analysis showed that more than 25% decrease in oxygen content of the collected liquid in the second condenser with HZSM-5 was observed compared with that without catalyst. The H/C, O/C molar ratios and the higher heating value of the oil fraction in the collected liquid with the catalyst were 1.511, 0.149 and 34.6 MJ/kg, respectively. It was indicated that the collected liquid in the second condenser had high qualities and might be used as transport oil.     

Torrefaction of sawdust in a fluidized bed reactor

In the present work, stable fluidization of sawdust was achieved in a bench fluidized bed with an inclined orifice distributor without inert bed materials. A solids circulation pattern was established in the bed without the presence of slugging and channeling. The effects of treatment severity and weight loss on the solid product properties were identified. The decomposition of hemicelluloses was found to be responsible for the significant changes of chemical, physical and mechanical properties of the torrefied sawdust, including energy content, particle size distribution and moisture absorption capacity. The hydrophobicity of the torrefied sawdust was improved over the raw sawdust with a reduction of around 40 wt.% in saturated water uptake rate, and enhanced with increasing the treatment severity due to the decomposition of hemicelluloses which are rich in hydroxyl groups. The results in this study provided the basis for torrefaction in fluidized bed reactors.     

Mathematical model for the fluidized bed biofilm reactor

A mathematical model is proposed for the fluidized bed biofilm reactor (FBBR). For individual biofilm-covered particles (bioparticles) within the reactor, an analysis of intrabiofilm mass transfer and simultaneous intrinsic zero order reaction yields an effectiveness factor expression which is a function of the modified, zero order Thiele modulus, Φ_0,m. This expression is linked to a one-dimensional reactor flow model and a fluidization model to yield an overall reactor model describing convective transport and simultaneous biochemical conversion of substrate within a FBBR. For Φ_0,m<1.15, FBBR is mass transfer limited and 0.45 order kinetics are observed. For Φ_0,m<1.15, mass transfer limitations are insignificant and intrinsic zero order kinetics are observed. A sensitivity analysis using the proposed mathematical model indicates that biofilm thickness and media size are the two most important operating parameters. These two parameters can be optimized simultaneously for a specific application. The proposed model provides a rational approach for FBBR design.     

Anaerobic biodegradation of diesel fuel-contaminated wastewater in a fluidized bed reactor

Diesel fuel spills have a major impact on the quality of groundwater. In this work, the performance of an Anaerobic Fluidized Bed Reactor (AFBR) treating synthetic wastewater is experimentally evaluated. The wastewater comprises tap water containing 100, 200 and 300 mg/L of diesel fuel and nutrients. Granular, inert, activated carbon particles are employed to provide support for biomass inside the reactor where diesel fuel is the sole source of carbon for anaerobic microorganisms. For different rates of organic loading, the AFBR performance is evaluated in terms of the removal of diesel fuel as well as chemical oxygen demand (COD) from wastewater. For the aforementioned diesel fuel concentrations and a wastewater flow rate of 1,200 L/day, the COD removal ranges between 61.9 and 84.1%. The concentration of diesel fuel in the effluent is less than 50 mg/L, and meets the Level II groundwater standards of the MUST guidelines of Alberta.     

Immobilized cells cultivated in semi-continuous mode in a fluidized bed reactor for xylitol production from sugarcane bagasse

Summary Xylitol production from sugarcane bagasse hemicellulosic hydrolyzate was evaluated in a fluidized bed reactor operated in semi-continuous mode, using cells immobilized on porous glass. The fermentative process was performed during five successive cycles of 72 h each one. The lowest xylitol production occurred in the first cycle, where a high cell concentration (12 g l⁻¹) was observed. In the subsequent cycles the xylitol concentration was ever increasing due to the cells adaptation to the medium. In the last one, 18 g xylitol l⁻¹ was obtained with a yield factor of 0.44 g g⁻¹ and volumetric productivity of 0.32 g l⁻¹ h⁻¹.