掘进巷道风流温度分布规律的数值模拟

根据紊流状态下的守恒原理 ,导出了描述掘进巷道风流紊流流动和温度分布的微分方程。通过对矿内风流流动及热力过程的理论分析及现场实测 ,系统地开展矿内风流流场和风流温度场的分布规律及其耦合作用机理的理论分析与研究 ,并利用PHOENICS程序进行数值模拟 ,初步得出了矿井掘进巷道风流温度与各种参数的变化规律。掘进巷道风流温度随风速提高呈负幂函数规律降低 ,随入风流温度升高而线性升高。     

An incident investigation on an unexpected loss of containment and damage to PHI-TEC II during acrylonitrile runaway tests

This article investigates a laboratory incident that occurred during the analysis of a thermal runaway reaction of acrylonitrile monomer. This failure, which was attributed to an human error, resulted in financial losses and corresponding unexpected results. The incident not only damaged the interior of the vessel and other instrument parts, but also exposed the researchers to considerable danger, necessitating their escape from the laboratory. The failure characteristics are discussed, and countermeasures are developed to prevent such a type of incident from reoccurring.     

Full scale treatment of ASR wastes in a modified rotary kiln

A plant, designed for the thermo-valorisation of tyres, was specifically modified in order to treat Automobile Shredder Residue (ASR). Results from two full-scale combustion experiments, carried out on large ASR feeding lots (thousands of tons) indicate the proposed technology as a potential route to help the fulfilling of impending 95% reuse and recovery target set by the End of life Vehicle (ELV) Directive (January 2015). The paper describes the main operational troubleshot occurred during the first experiment (emissions at the stack out of regulatory limits and problems of clogging on the conveyer belt) and the consequent upgrading solutions (pre-treatment, introduction of waste double low-flow screw feeder and a cyclone prior to the main fan, modification of rotatory kiln inlet) adopted to allow, during the second long-term experiment, a continuous basis operation of the plant in full compliance with the discharge limit to the atmosphere. Characterization of both ASR and combustion residues allowed to quantify a 18% of combustion residues as not dangerous waste while only the 2% as hazardous one. A pre-treatment for the reduction of fines in the ASR was recommended in order to achieve the required energy recovery efficiency.     

Succinate-bonded pullulan: An efficient and reusable super-sorbent for cadmium-uptake from spiked high-hardness groundwater

Chemically modified pullulan was evaluated for its sorption efficiency and selectivity to remove cadmium(Cd) from spiked high-hardness groundwater(GW). Pullulan esterified with succinic anhydride using dimethylaminopyridine showed a fairly high degree of substitution value as confirmed by1 H NMR spectroscopy. Pullulan succinate(Pull-Suc) was converted into the sodium salt(Pull-Suc-Na). The effect of contact time(5–200 min) and p H(2–8) on Cd-uptake by the sorbent(Pull-Suc-Na) was investigated. The sorbent showed more than 90% Cd-removal in first 15 min from distilled water(DW) and GW solution,respectively. Comparison of Pull-Suc-Na with other polysaccharidal sorbents suggested its high efficiency(DW 476.2 mg/g and GW 454.5 mg/g) and selectivity for the removal of Cd by an ion exchange mechanism, which is further supported by the negative Gibbs free energy values calculated from Langmuir isotherms. A Langmuir isotherm kinetic model provided the best fit for the sorption of Cd using Pull-Suc-Na. The sorbent showed a negligible decrease in Cd-uptake over three regeneration cycles. The thermal stability testing of the sorbents indicated that Pull-Suc-Na(sorbent) is more stable than Pull-Suc.     

中空玻璃受热破裂行为规律研究

研究了单层玻璃厚度为6mm,两块玻璃间距为6mm的中空玻璃的受热响应规律,分析了向火面和背火面玻璃板的表面温度、玻璃板向火面中心点处的热通量、两块玻璃的破裂时间、裂纹形态以及玻璃脱落情况等。定义玻璃边长区域范围为[-0.5L,0.5L],则玻璃首次起裂点均位于被遮蔽边上,且在[-0.25L,0.25L]的范围内。进一步研究了遮蔽方式对中空玻璃破裂行为的影响,在本实验条件下,四边遮蔽的向火面玻璃最易破裂,且左右垂直遮蔽比上下水平遮蔽情况下脱落程度严重。     

Simultaneous recovery of vanadium and nickel from power plant fly-ash: Optimization of parameters using response surface methodology

Simultaneous recovery of vanadium (V) and nickel (Ni), which are classified as two of the most hazardous metal species from power plant heavy fuel fly-ash, was studied using a hydrometallurgical process consisting of acid leaching using sulfuric acid. Leaching parameters were investigated and optimized in order to maximize the recovery of both vanadium and nickel. The independent leaching parameters investigated were liquid to solid ratio (S/L) (5–12.5 wt.%), temperature (45–80 °C), sulfuric acid concentration (5–25 v/v%) and leaching time (1–5 h). Response surface methodology (RSM) was used to optimize the process parameters. The most effective parameter on the recovery of both elements was found to be temperature and the least effective was time for V and acid concentration for Ni. Based on the results, optimum condition for metals recovery (actual recovery of ca.94% for V and 81% for Ni) was determined to be solid to liquid ratio of 9.15 wt.%, temperature of 80 °C, sulfuric acid concentration of 19.47 v/v% and leaching time of 2 h. The maximum V and Ni predicted recovery of 91.34% and 80.26% was achieved.     

王滩电厂脱硫系统经济运行初探

介绍了王滩电厂2×600MW机组石灰石—石膏湿法脱硫系统实现经济运行的经验,提出了降低电耗、水耗、石灰石耗量的具体措施。王滩电厂脱硫装置已投运三年多,其运行实践表明,通过采取上述措施,在额定工况下可保证脱硫效率达95%,且脱硫系统多项运行指标均优于设计值。     

Monitoring of pathogenic microorganisms contamination during heat drying process of sewage sludge

The sewage sludge from wastewater treatment plant is a potential source of infectious organism. The number and type of pathogens in sludge depends on various factors namely, the wastewater source, the type of treatment plant, and other environmental factors such as the biological medium offered by the sewage sludge. The principal sludge-borne diseases are presented followed by discussion on biological aspect of growth and occurrence. The overall objective of this work is to estimate kinetic reduction of pathogen population in sludge during different thermal-drying process including: the agitated conductive drying, drum drying, solar drying, and fry-drying. The temperature curves were reported from literature except frying data which were determined in experiment. In order to apply the temperature influence on pathogens population, kinetic parameters for the thermal inactivation (D, z-values) were chosen from literature. Values of concentrations of each pathogen were also extracted from scientific review of pathogens in bio-solids. This study conducted to resolve the survival kinetic of Hepatitis A viruses. The result showed that a concentration of 7 × 10⁴ cfu/100 ml initially present in the sewage sludge is significantly reduced during the heat drying processes except the solar plant. The sewage sludge is completely disinfected when heated for 20 min, 10 min, and 10 s, respectively, during the agitated conductive process, vacuum fry-drying, and drum drying process.     

Ignition characteristics, conditions of criticality and disappearance of criticality of cumene hydroperoxide reaction by modeling approach

The thermal explosion problem of cumene hydroperoxide exothermic reaction which is used in chemical industries for production of some chemical materials is investigated. The analytical solutions of the problem to determine the margin between ignition and non-ignition systems are presented. The solution offers different analytical expressions which relate between the critical parameters for both steady and unsteady-states in different planes of solutions for different cases. The numerical solutions in different planes offer different trajectories of solution as sub-critical (non-ignition) and supercritical (ignition). Also from the numerical solution the relations between the critical parameters are presented. The critical behaviors from both analytical and numerical solutions are concise and pertained the same results.     

贫烟煤氧化热解反应的动力学分析

通过运用热分析的技术研究平顶山烟煤以及郑州嵩枫贫煤氧化热解反应的动力学特性.依据转化率将煤样的TG曲线划分为两个不同的温度区间进行动力学机理函数的探讨.通过对比分析整个TG曲线的氧化受热情况,将线性较好的机理函数带入DSC曲线进行分析验证,并求解出动力学参数以分析其氧化热解反应的特点.研究得出:这两种煤的氧化热解过程相似但同等条件下反应程度不同;在不同的反应阶段其化学反应级数不同并且相应过程中的TG曲线和DSC曲线反应级数一致;煤反应的活化能随着煤与氧反应过程的深入而增加,指前因子随着活化能的增加而增加且煤氧化反应过程是个分阶段的、多步反应以及相互联系促进的过程.