序批式光生物反应器中光合细菌跨膜传输及产氢特性

以沼泽红假单胞菌CQK-01为实验菌种,研究了序批式光生物制氢反应器不同初始底物浓度和初始pH值对光合细菌葡萄糖跨膜传输速率、细胞膜渗透性及产氢性能的影响,计算了光合细菌细胞膜对葡萄糖的渗透系数。结果表明光合细菌细胞膜对底物渗透性及传输速率的影响随菌体生长环境及时间而异;在初始底物浓度较低时,葡萄糖最大跨膜传输速率随初始底物浓度的增大而增大,并在75mmol.L-1时取得最大值,而不同初始底物浓度下光合细胞膜对葡萄糖的最大渗透系数都约为250cm3.(gDW)-1.h-1;但高底物浓度下葡萄糖跨膜传输速率减小,最大渗透系数在150mmol.L-1时仅为116cm3.(gDW)-1.h-1;当培养基初始pH值为7.0时,光合细菌细胞膜对葡萄糖的渗透性最佳,葡萄糖跨膜传输速率最大为9.74mmol.(gDW)-1.h-1;实验工况下光合细菌平均产氢速率最大为0.26mmol.L-1.h-1,产氢得率最高为0.63molH2.(molglucose)-1。     

环流型光纤生物膜制氢反应器的连续产氢性能

采用使光合细菌生物膜直接附着生长在具有高导光性的弥散光纤表面的方法,构造了环流型光纤生物膜制氢反应器,用于解决目前固定化细胞连续流光生物制氢反应器研究中存在的难以同时实现细胞固定化和保持细胞固定化区域具有良好光分布性的问题。通过连续流产氢实验研究发现该反应器在以葡萄糖为有机底物,入射光波长为530 nm,弥散光纤表面光照强度为4.15 W·m^-2,进口底物浓度为10 g·L^-1,流速为100 ml·h^-1的条件下,反应器的光能转化效率和产氢速率得到显著提高,分别达到47.9%和0.83 mmol·(g dry cell)^-1·h^-1。实验结果表明,采用适合光合细菌产氢的入射波长,保持固定化细胞区域均匀的光强分布和强化传质的操作方法都有助于提高反应器的产氢性能。该研究可以为规模化光生物制氢反应器的探索提供一定参考。     

生物膜反应器降解结晶紫运行因素的研究

以金氏菌Kingella H为菌种,在填充活性炭的玻璃柱中挂膜建立固定化生物膜反应器.分析和考察了碳源浓度、氮源浓度、染料浓度、处理时间、初始pH值、进水温度和曝气量等因素对生物膜反应器处理结晶紫(CV)模拟废水的影响.结果表明,较低浓度的碳源和氮源即可维持反应器的正常运行,达到理想的脱色效果;CV对生物膜的活性有一定的抑制作用,但反应器仍可使浓度高达500 mg·L-1的CV模拟废水在30 min内的脱色率达97%以上;反应器的最佳运行条件是:进水的pH值为7,温度为35℃,处理过程中的曝气量为180 L·min-1.     

溶液浓差能驱动的逆电渗析反应器制氢实验研究

低品位热能制氢技术首先是将热能转换为溶液浓差能，然后通过逆电渗析（RED）反应器将溶液浓差能转换成氢能。为了验证RED反应器能将溶液浓差能转换为氢能，探索关键运行参数变化对能量转换过程的影响。设计了一个由40个膜对所构成的RED反应器，以NaCl水溶液为工作溶液，NaOH水溶液为电极液的制氢系统。通过改变浓/稀溶液入口浓度，溶液过膜流速以及输出电流来考察对RED反应器产氢率、制氢效率和能量转换效率的影响。实验结果发现，浓/稀溶液入口浓度，过膜流速变化均会影响RED反应器的输出电流。在外电路短接条件下，输出电流越大，反应器产氢率和制氢效率越高，但能量转换效率越低。     

移动床生物反应器启动特性研究进展

介绍了移动床生物膜反应器的工艺原理和特点、移动床生物膜反应器启动特性研究.指出移动床生物膜反应器采用普通悬浮填料挂膜启动时间长,移动床生物膜反应器间歇运行时如何实现快速挂膜启动以及在低温及变温条件下,移动床生物膜反应器挂膜启动时缺少加速生物膜生长和控制生物反应特性的运行资料等不足.     

声化学微反应器降解亚甲基蓝废水试验研究

为提高Fe²⁺活化过硫酸钠（SPS）降解亚甲基蓝（MB）的效率，设计了一种声化学微反应器。首先研究了静置系统、磁力搅拌系统、毛细管微反应器系统和声化学微反应器系统中MB和硫酸亚铁（FeSO₄）混合液pH值、FeSO₄浓度、SPS浓度对MB降解率的影响。其次，在声化学微反应器系统和毛细管微反应器系统中研究了流道结构和流速对MB降解率的影响。结果表明：在不同的MB和FeSO₄混合液pH值、FeSO₄浓度下，声化学微反应器系统中MB降解率均高于其他反应系统。随着SPS浓度的增加，MB降解率呈上升趋势，但在声化学微反应器系统中增加SPS浓度会影响MB降解。相比于直线形、三角波形和半圆波形流道结构，MB在矩形波形流道结构中降解效率更高。溶液在管道内停留时间相同时，增加流速更有利于氧化降解反应的进行。实验表明：当MB浓度为0.2 mmol·L^-1，MB和FeSO₄混合液pH值为3、FeSO₄浓度为1.4 mmol·L^-1、SPS浓度为1.8 mmol·L^-1，流道结构为矩形波形，流速为13.16 cm·s^-1时，声化学微反应系统中MB降解率达到85.45%。     

热激活过硫酸盐降解莠灭净的动力学研究

研究热激活过硫酸盐对莠灭净的去除效果以及反应动力学模型,考察反应温度、底物初始浓度、氧化剂浓度和溶液初始pH对莠灭净降解动力学的影响,并对反应中生成的主要自由基进行鉴定。结果表明,热激活过硫酸盐系统中莠灭净的降解均符合准一级反应动力学模型(R2≥0.93)。随着反应温度的增加,莠灭净降解加快,准一级反应速率常数kobs增大;随着底物初始浓度的增加,莠灭净降解率减小,kobs减小;增加氧化剂的投加量,可以促进莠灭净降解;随着溶液pH的增大,kobs先增大后减小,中性条件下莠灭净降解率最大;pH为7时,热激活过硫酸盐系统中反应生成的自由基主要是·SO4-。     

热激活过硫酸盐降解莠灭净的动力学研究

研究热激活过硫酸盐对莠灭净的去除效果以及反应动力学模型,考察反应温度、底物初始浓度、氧化剂浓度和溶液初始pH对莠灭净降解动力学的影响,并对反应中生成的主要自由基进行鉴定。结果表明,热激活过硫酸盐系统中莠灭净的降解均符合准一级反应动力学模型(R2≥0.93)。随着反应温度的增加,莠灭净降解加快,准一级反应速率常数kobs增大;随着底物初始浓度的增加,莠灭净降解率减小,kobs减小;增加氧化剂的投加量,可以促进莠灭净降解;随着溶液pH的增大,kobs先增大后减小,中性条件下莠灭净降解率最大;pH为7时,热激活过硫酸盐系统中反应生成的自由基主要是·SO4-。     

啤酒废水对IC反应器启动阶段的影响

本实验以啤酒废水(啤酒葡萄糖配水)为底物启动IC(厌氧内循环)反应器,在HRT为6h,温度为35±1℃的条件下试运行至启动阶段,其实验结果与同等条件下以糖蜜(红糖)废水运行的IC反应器的启动阶段结果数据(COD去除率与出水pH值)作对比分析,得到啤酒废水加入底物中对IC反应器启动运行的影响:(1)COD去除率前期较高,可达到60%以上,后期降低,趋于30%;(2)出水pH值降低至4以下;(3)系统不稳定。并根据以上分析对实验的改进提出建议。     

好氧氨氧化生物膜内氧传质特性及影响因素

采用理论计算和实验测试相结合的方法,对流化床反应器中好氧氨氧化生物膜内溶解氧传质特性及影响因素进行了分析。建立了综合考虑反应-扩散-对流作用的一维模型,计算结果表明:溶解氧所能到达的生物膜厚度受渗流速度等因素的影响;增大渗流速度、扩散系数和进水底物浓度均可以提高膜内溶解氧浓度的最大值。建立了序批式流化床生物膜反应器,获得了高于80%的氨氮转化率,实现了好氧氨氧化生物膜的成功挂膜,获得生物膜厚度为0.1～0.3 mm,采用微电极测试了膜内溶解氧浓度。实验测试和模型计算结果表明,溶氧浓度沿生物膜厚度方向均呈现出抛物线形的不均匀下降趋势,且当扩散系数为2.2×10–4 m2/s和渗流速度为6.0 mm/s时,测试结果和计算数值具有较好的吻合度。     

A TYPICAL APPLICATION OF MAGNETIC FIELD INWASTEWATER TREATMENT WITH FLUIDIZED BED BIOFILM REACTOR

The effects of a magnetic field on wastewater treatment with a fluidized bed biofilm reactor was investigated. With glucose being the sole carbon source, the activated sludge obtained from a real wastewater treatment plant was used as a seed. Magnetically loaded polystyrene beads at the size of 500-595 μm were used as support materials for biofilm formation in a fluidized bed biofilm reactor. Magnetic field application allowed the operation of the column at high liquid flow rates, thus external diffusion limitations on the biofilm surface were lowered and the efficiency of biodegradation was increased. Denser, thinner, and more active biofilm was obtained with magnetic field application, especially in pulsed form. As expected, the system performance changed with operational parameters, and the increase in substrate removal reached up to 26% with pulsed application of a 17.8 mT DC-magnetic field under optimum conditions.     

A typical application of magnetic field inwastewater treatment with fluidized bed biofilm reactor

The effects of a magnetic field on wastewater treatment with a fluidized bed biofilm reactor was investigated. With glucose being the sole carbon source, the activated sludge obtained from a real wastewater treatment plant was used as a seed. Magnetically loaded polystyrene beads at the size of 500-595 w m were used as support materials for biofilm formation in a fluidized bed biofilm reactor. Magnetic field application allowed the operation of the column at high liquid flow rates, thus external diffusion limitations on the biofilm surface were lowered and the efficiency of biodegradation was increased. Denser, thinner, and more active biofilm was obtained with magnetic field application, especially in pulsed form. As expected, the system performance changed with operational parameters, and the increase in substrate removal reached up to 26% with pulsed application of a 17.8 mT DC-magnetic field under optimum conditions.     

Dual substrate limitations in upflow packed-bed biofilm reactors — a theoretical study

The performance of an upflow packed-bed biofilm reactor has been analyzed under dual substrate limitation conditions. The numerical solution of the proposed equations defining the system has been obtained for a wide range of operating conditions for a case of practical significance involving glucose and oxygen as dual substrates. The results show that the inlet glucose concentration defines the limiting substrate at a position near the inlet of the reactor. For inlet glucose concentrations up to 300 mg/l, glucose acts as the limiting substrate. However, for inlet concentrations of 400 mg/l of glucose or higher, oxygen assumes the role of the limiting substrate at that position. For all other positions in the reactor, glucose acts as the limiting substrate, irrespective of its inlet concentration. Extensive computations were performed in order to define regions where glucose, oxygen or both are limiting. The predicted results have been found to be in agreement with the theoretical criteria, proposed in the literature, of determining the limiting substrate.     

厌氧与光合微生物联合制氢工艺实验研究

利用厌氧细菌暗发酵产氢和光合细菌光发酵产氢的优势和互补协同作用而联合起来的两步法制氢,探讨不同底物浓度对厌氧发酵阶段产氢的影响、厌氧发酵时间对产氢发酵过程的影响;光合微生物发酵随发酵时间的产氢情况。结果表明,葡萄糖浓度对厌氧生物产氢有很大的影响, 15 g/L 的葡萄糖浓度有较好的产氢量。葡萄糖利用率和挥发性脂肪酸的总量随厌氧发酵时间的变化情况表明,在厌氧发酵阶段,以葡萄糖为底物,最佳的葡萄糖浓度为 15 g/L。在 37 h 的葡萄糖利用率达到 72.08%,挥发性脂肪酸总量达到 9 326.3 mg/L,每克葡萄糖累计产氢量为 182 mL。在厌氧发酵时间 37 h 时把厌氧发酵的产物移到光合发酵反应器,接种位于生长对数期的光合细菌群,调节培养液的pH值和加入光源进行光合产氢,88 h 时每克葡萄糖累计产氢达到 352 mL,两步联合制氢每克葡萄糖累计产氢量共可达到 534 mL。     

Steady-state performance of a continuous biofilm fermentor system for penicillin production

Steady-state performance of a three-phase fluidized-bed biofilm fermentor system, which is used for production of penicillin, is analyzed by considering two ideal contacting patterns, i.e., complete-mixed and plug-flow ones. At steady state, the biofilm thickness is kept constant by assuming that the microbial growth is balanced with cell decay processes. From the simulation analyses, it was found that a complete-mixed contacting pattern gives superior performance to plug-flow one in both outlet product concentration and specific productivity of the reactor system. The inhibitory effect of the carbon source, glucose, is found to be less pronounced in the former configuration, and this fact is considered an important criterion for the design purposes. Optimum biofilm thickness for the biofilm fermentor system was found to be a function of various operating parameters such as inlet substrate concentration and oxygen transfer capacity of the system. It should therefore not be determined directly from the penetration depth of a limiting nutrient, but from information on the interactions between reactor productivity and those operating variables.     

光合细菌的葡萄糖跨膜传输及代谢产氢模型

引言光合细菌产氢具有底物转化效率高、吸收光谱范围广、无污染、能耗低、操作简单的优点[1-2]。目前,关于光合细菌的底物跨膜传输和产氢方面的理论研究相对较少[3-4]。Vrabl等[5-6]研究了葡萄糖的跨膜传输过程,分析了细胞膜上的载体蛋白运输特性;Wayman等[7]建立了Aspergillus niger     

操作参数对余热回收甲醇水蒸气重整制氢过程的影响

以模拟汽车尾气供热的甲醇水蒸气重整（MSR）制氢反应为研究对象,设计了集余热加热与MSR制氢反应于一体的肋式微反应器,考察了反应器进口热风速度、温度,反应物进口速度、温度、水醇比及顺逆流情况对MSR制氢过程的影响。计算结果表明,逆流、水醇比1.3、热风进口速度1.1 m/s、温度773 K、反应物进口速度0.1 m/s、温度493 K为该反应过程的最佳工况参数,此时甲醇转化率为99.4%,模拟汽车尾气余热的热效率为28%,反应器出口氢气的体积分数为69.6%。研究结果对开展余热综合利用及发动机尾气重整制氢掺氢燃烧的研究有借鉴意义。     

Modelling of packed bed membrane reactors for autothermal production of ultrapure hydrogen

The conceptual feasibility of a packed bed membrane reactor for the autothermal reforming (ATR) of methane for the production of ultrapure hydrogen was investigated. By integrating H₂ permselective Pd-based membranes under autothermal conditions, a high degree of process integration and intensification can be accomplished which is particularly interesting for small scale H₂ production units. A two-dimensional pseudo-homogeneous packed bed membrane reactor model was developed that solves the continuity and momentum equations and the component mass and energy balances. In adiabatic operation, autothermal operation can be achieved; however, large axial temperature excursions were seen at the reactor inlet, which are disadvantageous for membrane life and catalyst performance. Different operation modes, such as cooling the reactor wall with sweep gas or distributive feeding of O₂ along the reactor length to moderate the temperature profile, are evaluated. The concentration polarisation because of the selective hydrogen removal along the membrane length was found to become significant with increasing membrane permeability thereby constraining the reactor design. To decrease the negative effects of mass transfer limitations to the membrane wall, a small membrane tube diameter needs to be selected. For a relatively small ratio of the membrane tube diameter to the particle diameter, the porosity profile needs to be taken into account to prevent overestimation of the H₂ removal rate. It is concluded that autothermal production of H₂ in a PBMR is feasible, provided that the membranes are positioned outside the inlet region with large temperature gradients.     

Removal of NO by using Fenton reagent solution in a lab-scale bubbling reactor

Removal of NO was studied in a lab-scale bubbling reactor. Effects of operation parameters such as pH value, H₂O₂ concentration, NO inlet concentration and reaction temperature on NO removal efficiency were investigated. The operation parameters included 250–1000 ppm NO, 0.5–1.5 mol/L H₂O₂, FeSO₄ 0.05 mol/L, 2–6 pH, 25–70 °C. As can be seen from the experimental results, pH value had a great impact on NO removal efficiency. The experimental results indicated that the gas–liquid reaction between NO and Fenton reagent solution was liquid-film controlled as NO inlet concentration exceeded 600 ppm. And NO removal efficiency decreased with increasing reaction temperature.