预处理方法对香蒲厌氧发酵联产H2-CH4效能的影响

通过厌氧发酵动力学分析、还原糖及其他代谢产物变化情况,结合香蒲微观结构解析,系统研究酸(HCl)、碱(NaOH)、酶(纤维素酶R-10)3种预处理对水生植物厌氧发酵联产H₂-CH₄的影响. 结果表明:香蒲分别经酸、碱、酶3种预处理后,厌氧发酵联产累积H₂、CH₄产量及含量均显著提高,c(HCl)、c(NaOH)均为1.0mol/L, w(纤维素酶R-10)(以底物计)为10mg/g时,预处理最佳. 其中1.0mol/L NaOH预处理香蒲效果最佳,φ(H₂)(H₂含量)达30.09%,累积产H₂量(以香蒲干质量计)达11.39mL/g;φ(CH₄)(CH₄含量)最高达67.48%,累积产CH₄量(以香蒲干质量计)达41.87mL/g;还原糖利用率达50.87%,sCOD(溶解性化学需氧量)利用率达66.17%. 纤维素酶预处理后香蒲产CH₄能力显著提高,产CH₄阶段φ(CH₄)最高为71.39%,累积产CH₄量达46.32mL/g,还原糖利用率达72.10%. 扫描电镜微观结构分析表明,碱预处理对香蒲纤维素结构破坏程度最大,可有效增加香蒲与微生物接触面积,有利于厌氧发酵联产H₂-CH₄工艺的快速启动和稳定运行.      

Thermodynamic method for the prediction of solid CO2 formation from multicomponent mixtures

The increase in GHG concentration has a direct effect on global climate conditions. Among the possible technologies to mitigate GHG emissions, CCS is being accepted to gain emission reduction. Such technology also involves cryogenic CO₂ capture processes based on CO₂ freeze-out or where the formation of solid CO₂ must be avoided. Captured CO₂ is usually transported in pipelines for the reinjection.The risk associated to the release of CO₂ is due to the changing temperatures and pressures the system may experience, which can lead to the deposition of solid CO₂ where it must be avoided. Prolonged exposure to dry ice can cause severe skin damage and its resublimation could pose a danger of hypercapnia. It is, thus, necessary to build up a tool able to predict the conditions in which CO₂ can freeze-out.A thermodynamic methodology based on cubic EoSs has been developed which is able to predict solid–liquid–vapor equilibrium of CO₂ mixtures with n-alkanes or H₂S which are usually found in equipment for acidic gas, mainly natural gas, treatment.The focus is a detailed analysis of the method performances when more than two components are present since, for such a case, literature does not provide significant modeling results.     

湿润剂溶液在硫化矿矿尘中的反向湿润行为研究

采用毛细管反向渗透湿润实验方法,研究了两种阴离子型湿润剂对两种硫化矿矿尘的反渗长度与反渗时间的关系.在实验中,环境和溶液的温度不高(20℃左右),所选的两种湿润剂对硫化矿矿尘都具有一定的改善湿润效果作用,试剂A比试剂B稍好.在反渗长度1 cm内,其反渗长度与反渗时间接近线性关系;反渗长度增大,其反渗长度与反渗时间近乎成抛物线的关系.研究结果显示,用毛细管反渗湿润法研究湿润剂对硫化矿矿尘的湿润行为时,反渗时间与反渗长度的关系基本可用Washburn方程描述;但除了方程中所含的参数外,还存在着诸多的影响因素,如几何条件、矿尘的物理化学性质、湿润剂的种类和浓度梯度等.     

催化裂化装置硫化氢腐蚀问题及防治对策

阐述了H2S对设备的腐蚀机理,具体分析了催化裂化装置MIP-CGP技术改造后硫分布的新情况,从选材、工艺防腐、表面防腐、焊接质量控制和检测技术等方面提出了防硫化氢腐蚀的对策措施.     

高效填料塔生物反应器处理制药废水处理厂含硫臭气

采用装有特制ZX01型填料的生物反应器,对某药厂废水处理厂产生的含硫臭气进行了近4个月的连续脱臭试验.结果表明:该填料塔生物反应器的最大容积负荷N_v≤204g/(m³·h)时,H₂S去除率接近100%,H₂S代谢产物主要以SO₄^2-为主.采用少量含N、P等营养物的二次沉淀池出水为喷淋水,其最适喷淋率为3.56L/(L·d).该填料塔有较强的抗负荷冲击能力,塔内阻抗低,无堵塞现象,无需经常进行反冲洗,可长期稳定运行.     

气体分离循环对高温厌氧消化过程的影响

采用厌氧序批式反应器,研究了气体循环(包括气体直接循环和脱除气体中的氢气后循环)对以葡萄糖和乙酸钠配制的模拟废水在高温厌氧消化过程中乙酸代谢速率、出水性质及微生物相的影响,并采用尺寸排除色谱和三维荧光光谱技术,对溶解性微生物产物(SMP)的分子量分布和荧光物质组成进行了分析.结果显示,气体循环使得出水中残余挥发性脂肪酸的浓度由238.2mg/L(未脱氢)和129.6mg/L(脱氢)分别减少至8.5mg/L和8.2mg/L,并最终降低了SMP产量,45d时分别降至气体循环前的36.8%和59.2%.脱氢气体循环促进了乙酸化和乙酸氧化,导致了微生态环境和甲烷化基质浓度的差异,促进了高分子量SMP向低分子量SMP的转化,污泥中的微生物形态亦发生了较大变化.可见气体循环改善了基质与微生物的混合状况,改善了出水水质,而脱氢气体循环加速了乙酸的代谢,有望更快速地解除易降解有机物高温厌氧消化过程中的酸抑制,提高厌氧消化效率.     

Continuous biohydrogen production from diluted molasses in an anaerobic contact reactor

An anaerobic contact reactor (ACR) system comprising a continuous flow stirred tank reactor (CSTR) with settler to decouple the hydraulic retention time (HRT) from solids retention time (SRT) was developed for fermentative hydrogen production from diluted molasses by mixed microbial cultures. The ACR was operated at various volumetric loading rates (VLRs) of 20–44 kgCOD·m^-3·d^-1 with constant HRT of 6 h under mesophilic conditions of 35°C. The SRT was maintained at about 46–50 h in the system. At the initial VLR of 20 kgCOD·m^-3·d^-1, the hydrogen production rate dropped from 22.6 to 1.58 L·d^-1 as the hydrogen was consumed by the hydrogentrophic methanogen. After increasing the VLR to 28 kgCOD·m^-3·d^-1 and discharging the sludge for 6 consecutive times, the hydrogentrophic methanogens were eliminated, and the hydrogen content reached 36.4%. As the VLR was increased to 44 kgCOD·m^-3·d^-1, the hydrogen production rate and hydrogen yield increased to 42.1 L·d^-1 and 1.40 mol H₂·molglucose-consumed^-1, respectively. The results showed that a stable ethanol-type fermentation that favored hydrogen production in the reactor was thus established with the sludge loading rate (SLR) of 2.0–2.5 kgCOD·kgMLVSS^-1·d^-1. It was found that the ethanol increased more than other liquid fermentation products, and the ethanol/acetic acid (mol/mol) ratio increased from 1.27 to 2.45 when the VLR increased from 28 to 44 kgCOD·m^-3·d^-1, whereas the hydrogen composition decreased from 40.4% to 36.4%. The results suggested that the anaerobic contact reactor was a promising bioprocess for fermentative hydrogen production.     

Effect of white African mineral hair dye on the activities of phosphatases and malondialdehyde level in selected tissues of albino rats

The effect of white African mineral dye Yombofita (YF) on the activities of alkaline phosphatase (ALP), acid phosphatase (ACP) and malondialdehyde (MDA) levels in the skin, liver, kidney and serum of albino rats was investigated. The chemical analysis of the dye was first carried out using solubility test, pH determination and X-ray fluorescence (XRF) elemental analysis. Six different concentrations (0.05, 0.15, 0.25, 0.5, 0.75 and 1.00%) of the dye were prepared using hydrogen peroxide (30 volume) as solvent. A total of 80 albino rats (Rattus norvegicus) were used for the study. The rats were divided into 8 groups of 10 each and were maintained on commercial feed for the period of the experiment i.e. 30 days. In group 1, the control group, the animals were applied distilled water on their heads, whereas in group 2 the vehicle i.e. hydrogen peroxide was applied. In groups 3 to 8 various concentrations of YF (white) dye ranging from 0.05, 0.15, 0.25, 0.5, 0.75 to 1.00% was applied respectively. At the end of the experiment, blood samples were collected and portions of the selected tissues were excised for the determination of ALP and ACP activities. The MDA level was also determined in the skin of experimental animals. The results revealed a significant decrease (p?p?相似文献   

A comprehensive model to estimate the simultaneous release of acidic and basic gaseous pollutants from swine slurry under different scenarios

Swine slurry is a source of atmospheric pollutants. Emissions of basic and acidic compounds from slurry are largely dependent on the surface pH. In a storage system, the pH at the surface layers changes over time due to the volatilisation of ammonia (NH₃), carbon dioxide (CO₂) and acetic acid (HAc). In this article, a comprehensive gas emission–pH (GE–pH) coupled model is proposed to describe the simultaneous release of acidic and basic gaseous pollutants from swine slurry. The model was applied to describe the release of NH₃, CO₂, HAc and hydrogen sulphide (H₂S) from standard slurries stored in animal houses, outside storage tanks and lagoons. The modelled results agreed well with values reported in the literature and could be reasonably interpreted. The key parameters affecting the release of gases were: initial pH, initial concentration of total ammonium nitrogen and inorganic carbon, slurry temperature and air velocity. This study suggests that future modelling studies on gas emissions from animal slurry should consider the concentration of inorganic carbon and the frequency in which the slurry surface is mixed or altered, because they affect the surface pH and the release of gaseous pollutants from slurry.     

Thermodynamic investigation of the effect of oxygen and hydrogen chloride potential upon generation and decomposition behavior of dioxins

The thermodynamic equilibrium of the C‐H‐O‐Cl system has been calculated to elucidate the generation and decomposition behavior of dioxins, and is discussed from the viewpoint of the oxygen and hydrogen chloride potential. The dioxins behavior is greatly dependent on the oxygen potential, i.e. higher temperature and oxygen potential lead to the complete decomposition of dioxins, while low hydrogen chloride potential under insufficient oxygen condition leads to an increase of multi‐chlorine displacement of dioxins.