京唐高炉高球比下含铁固废流重构解析

京唐二期建成投产后拟将高炉球团比例从30%提高到50%,工艺配置与原料条件发生重大变化。根据循环极限理论推导了烧结矿、高炉除尘灰的钾、钠、锌元素极限含量和高炉钾、钠、锌元素极限入炉负荷。结果表明,京唐二期投产后如果高炉旋风灰仍返回烧结回收使用,将导致高炉入炉锌负荷显著提高,因此提出以高炉稳定顺行为目标的含铁固废流重构技术,将含锌固废集中于转底炉进行脱锌和金属化处理,再返回高炉或转炉使用,确保入炉锌负荷可控。

厌氧消化法处理火电厂柠檬酸洗锅炉废液的试验研究

本试验采用容积为10升普通消化滤池,选择氧化沟底层黑污泥为种泥,在控制pH为6.8～7.2,温度为35～37℃的中温发酵条件下,对模拟火电厂柠檬酸洗废液(COD为35000mg/l,pH值为4,Fe为3000mg/l),控制容积负荷为3kg/m^3。dCOD逐渐增至7kg/m^3·dCOD的情况下,进行半动态厌氧发酵试验,结果表明厌氧消化滤池,对柠檬酸洗锅炉废液的处理达到80％左右的去除效果。同时厌氧发酵产生以甲烷为主的混合气体(沼气),可供收集利用,可实现环境效益与经济效益的统一。

Study on fluidized-bed pyrolysis of waste paper

A lab-scale fluidized bed is setup and pyrolysis experiments are carried out. When temperature ranges from 400 to 700 ℃, the yields of solid residue, bio-oil and syngas range from 36% to 18%, 19% to 30% and 9% to 42%, respectively, and the mass balance of pyrolysis ranges from 80% to 95%. At 400 to 700 ℃, the characteristics of bio-oil are similar and the heat value is about 10 MJ/kg. When the temperature is over 600℃, the yield of syngas increases approximately twice as much as that at 500 ℃. The yields of CO2 and CO increase from 70 to 230 L/kg and 50 to 106 L/kg, respectively, while the yield of syngas only increases about 5% when the temperature increases from 600 to 700 ℃. The results indicate that the pyrolysis mechanism of waste paper is similar from 400 to 700 ℃, while the yield of syngas can be affected by secondary pyrolysis of bio-oil.

炼油厂氢网络超结构优化方法的改进及应用

在用超结构建模方法优化废氢流股回收网络时,往往会遇到模型求解难度大,甚至无法得到最优解的情况。将废氢流股中组分表征为氢气、可凝轻烃和燃料气3种资源,建立三角坐标表征,探讨资源回收优化方法,由此形成物料平衡及流股走向的相应约束,并结合数学建模方法建立了一种改进的超结构优化模型。用某炼油厂案例对该模型进行验证,结果表明:同等计算条件下,常规建模方法和改进建模方法分别运算5.3 s和1.6 s后获得计算结果;前者对部分流股的去向优化并未达到最优,获得了次优解,而改进方法计算速度更快,并获得最佳匹配网络;两者的经济效益分别为1063,2144万元/a,后者较前者获得了1081万元/a的超额收益。

Impact of material and energy flow variation-based iron /steel ratio on production cost

This paper establishes a model for the production cost of iron and steel enterprise.The variation rule of the production cost versus the iron/steel ratio for two cases, namely,fixed steel production and a fixed amount of molten iron,is analyzed,and the concept of a steel scrap threshold price is proposed.According to the analysis results,when the steel scrap unit price exceeds the steel scrap threshold price, an increase in the iron/steel ratio can reduce the production cost,and vice versa.When the gap between the steel scrap unit price and the steel scrap threshold price is relatively large, the impact of the iron/steel ratio on the production cost is more prominent.According to the calculation example,when steel production is fixed （284 358 t/month）and the steel scrap unit price is 263.2 yuan/t more than the steel scrap threshold price,an increase of 0.01 in the iron/steel ratio causes a monthly production cost reduction of approximately 750 000 yuan （2.63 yuan/t）.When the amount of molten iron is fixed （270 425 t/month）and the steel scrap unit price is 140.7 yuan/t more than the threshold price,an increase of 0.01 in the iron/steel ratio causes a monthly production cost reduction of approximately 430 000 yuan （1.5 yuan/t）.The results indicate that iron and steel enterprise should adjust the production strategy in time when the scrap price fluctuates, and then the production cost will be reduced.

CHARACTERISTICS OF THERMOPHILIC ANAEROBIC ACIDOGENESIS OF STARCH WASTEWATER

Acidogenic dissimilation of synthetic starch wastewater (1 000～10 000 mg COD·L -1 ) was studied in a thermophilic (55 ℃) upflow anaerobic sludge blanket (UASB) reactor.The production of volatile fatty acids (VFA) was proportional to the chemical oxygen demand (COD) loading rate.The yield of VFA was around 0.28 g VFA/g COD over the COD loading rate from 1.25 to 30 g COD·L -1 ·d -1 and the hydraulic retention time from 8.8 h to 24 h.Distribution of organic acids,the contents of propionic and butyric acids in the effluent in particular were also dependent on the COD loading rate.The thermophilic UASB reactor showed a stable performance on hydrolysis and acidogenesis of starch as well as suspended solid removal at short hydraulic retention times and high influent pH(10～11),during the operation of 110 d.

A New Method for Effluent Treatment System Design

this paper mainly discusses the design of distributed effluenttreatment systems with single contami- nant. A new method is putforward and four basic rules are provided. The key point of themethod is that global optimality is obtained by guaranteeing theoptimality of each step taken in the design. Costs per unit mass ofremoved contaminant are used as a scale to choose the nextcombination of an effluent stream and a treatment process. Theremaining problem is updated after each choice. As for multiplecontaminants, a two-stage method is adopted.

CFD-DEM simulation of fluid-solid flow of a tapered column separation bed

Research on recycling waste Printed Circuit Boards(PCB) is at the forefront of preventing environmental pollution and finding ways to recycle resources.The Tapered Column Separation Bed(TCSB) is invented aiming at disposing the problem that fine particles of waste printed circuit boards cannot be separated efficiently so as to obtain further insight about the underlying mechanisms and demonstrate the separation feasibility in the tapered column separation bed.In this work,a Computational Fluid Dynamics(CFD) coupled with Discrete Element Method(DEM) model for two-phase flow has been extended to simulate the fluid-solid flow in the tapered column separation bed.Its validity is demonstrated by its successful capturing the key features of particles' flow pattern,velocity,the pressure distribution,the axial position with time and axial force for particles with different densities.Simulation results show that the plastic particles and resin particles become overflow,while copper particles,iron particles and aluminum particles successively become underflow,with a discharge water flow rate of 1 m^3/h,an obliquity of 30°.The simulated results agree reasonably well with the experimental observation.Using this equipment to separate waste PCBs is feasible,theoretically.

Green Processes： Transforming Waste into Valuable Resources

1. Introduction Over the next few years, the manufacturing industry worldwide will face intense challenges, as finite supplies of raw materials dwindle and the cheap energy from fossil fuels becomes scarcer. Many conventional manufacturing processes will be outlawed on environmental grounds. For engineers and scientists, these inter- related problems also present an enormous opportunity. Robust new technologies are needed： They must be cost effective and energy efficient, and they must minimize pollution.

Combined treatment of dyeing wastewater by a new sequential bi-cycling biological fluidized bed

A new wastewater treatment equipment, the bi-external recycling biological fluidized bed (BRBFB), which is an effective equipment, was investigated. Anaerobic digestion, aerobic aeration and settlement processes with a fixed sequential procedure were compacted into this reactor. By five different treatment courses, the optimization of the combined operation procedure in the system was determined to be a 12-hour cycle including an inflow process, a 4 h anaerobic digestion process, a 4 h aerobic aeration process, a 2 h settlement process and a 2 h recess process including effluent discharge process. By utilizing BRBFB to treat a synthetic dyeing wastewater, 90% of COD_ Cr is removed for a higher-concentration water (COD_ Cr 1 000-1 200 mg/L), and 82% of COD_ Cr is removed for a lower-concentration water (COD_ Cr 400-600 mg/L). Near 100% color is removal and discharging standards for industry wastewater are achieved.

Flow-Induced Acoustic Resonances in Exhaust Gas Economizer Tube Banks

To investigate the conditions under which acoustic resonances occur, staggered arrays of closely spaced rigid tubes were tested in a wind tunnel under various flow velocities. The author investigated the Strouhal numbers at which flow periodicities occur, the relation between these Strouhal numbers and those at which acoustic resonances occur, and the effects of Reynolds number and longitudinal tube spacings on the occurrence of acoustic resonance. This investigation showed the following： （1） Acoustic resonance can be produced at a frequency well removed from that of vortex shedding. The results also show evidence of vortex shedding and acoustic resonance existing simultaneously but at different frequencies. （2） Acoustic resonance behavior is consistent with that of a self-excited system. （3） A new model of this phenomenon provides an improved procedure for avoiding acoustic resonances in closely spaced tube banks.

Preparation of Arsenic Oxide and High Purity Ultrafine Antimony Compounds from Flue Dust Containing Arsenic and Antimony

A new hydrometallurgical process of chlorination-distillation at low temperatures about 100 °C was developed for recovery of valuable metal and environmental protection. This process was used to treat flue dust containing arsenic and antimony and satisfactory results were obtained. Over 99% of arsenic and antimony were recovered, and high purity As2O3 and SbCl3 were produced. A metallic alcoholate technique was developed and proved to be of significant to the utilization of antimony resources. Using this technique, a number of antimony oxide powders were prepared, such as high purity and ultrafine Sb2O3, ultrafine Sb2O3-Sb2O5 and Sb2O3-SnO2 composite powders.

“改土归流”新论——以明清之交水西土司的“削地贬秩”“废土设流”“改土设流”与“废土归流”为典型案例

"改土归流"是明朝到清朝时期一系列"削地贬秩"、"废土设流"、"改土设流"与"废土归流"等历史事件的笼统称谓,其内涵则是具体、多样和复杂的。水西土司的裁革历程具有典型性和代表性,为雍正以后的"改土归流"提供了范本。

Numerical simulations of water flow and contaminants transport near mining wastes disposed in a fractured rock mass

A numerical tool, called Hydro-Geosphere, was used to simulate unsaturated water flow and contaminants migration around an open pit filled with mining wastes. Numerical simulations had been carried out to assess the influence of various factors on water flow and solute transport in and around the surface openings including recharge, properties of the waste material and presence of fractures in the surrounding rock mass. The effect of the regional hydraulic gradient was also investigated. The analyses were conducted by simulating various 2D cases using experimentally obtained material properties and controlled boundary conditions. The effects of the hydrogeological properties of the filling material(i.e., water retention curve and hydraulic conductivity function), fracture network characteristics and conductivity of the joints were assessed. The results illustrate that fractures control water flow and contaminants transport around the waste disposal area. A fracture network can desaturate the system and improve the regional gradient effect.

Degradation of Wastewater Containing Nitrobenzene by High Gravity-Ultrasonic/Ozonation/Electrolysis Technology

The integrated high gravity-ultrasonic/ozonation/electrolysis technology was applied in the pretreatment of wastewater containing nitrobenzene. The effect ofpH value, high gravity factor, liquid flow-rate and electric current density on removal of COD and nitrobenzene compounds was investigated. Experimental results have determined the optimal pro- cess regime involving a high gravity factor of 100, an electric current density of 20 mA/cm2, a liquid flow-rate of 100 L/h, and an initial liquid pH value of 11. After the wastewater had been treated for 180 rain, the degradation of nitrobenzene and COD reached 99% and 80%, respectively, with the biochemical coefficient （BOD/COD） equating to 0.64, and the subse- quent treatment of wastewater could be carried out by conventional biochemical means. Compared with traditional aeration- ozone contactors, a rotating packed bed with high mass transfer characteristics could be used to increase the ozonation treat- ment efficiency.

Hydrodynamic behaviour of the lateral flow biological aerated filter

Pulsed signal experiment was carried out to determine the hydrodynamic behaviours of lateral flow biological aerated filter(LBAF). With the analysis of experimental results, LBAF is viewed as an approximate plug flow reactor, and hydraulic retention time distribution function was derived based on LBAF. The results show that flow rate and aeration strength are two critical factors which influence flow patterns in LBAF reactor. The hydrodynamic behaviour analysis of LBAF is the theoretical basis of future research on improving capacity factor and developing kinetic model for the reactor.

Electrochemical treatment of wastewater containing chlorophenols using boron-doped diamond film electrodes

The electrochemical treatment of wastewater containing chlorophenols （2-monochlorophenol, 4-monochlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol） was carried out experimentally with synthetic boron-d0ped diamond （BDD） thin film electrodes. Current vs time curves under different cell voltages were measured. Removal rate of COD, instant current efficiency （ICE） and energy consumption were investigated under different current densities. The influence of supporting media is reported, which plays an important role in determining the global oxidation rate. The oxidative chloride is stronger than peroxodisulphate. The electrochemical characteristics of boron-doped diamond electrodes were investigated in comparison with active coating Ti substrate anode （ACT）. The experimental results show that BDD is markedly superior to ACT due to its different absorption properties.

Industrial and Agricultural Effects on Water Environment and Its Optimization in Heavily Polluted Area in Taihu Lake Basin, China

The deteriorating water quality in the Taihu Lake Basin has attracted widespread attention for many years, and is correlated with a sharp increase in the quantity of pollutant discharge such as agricultural fertilizers and industrial wastewater. In this study, several factors were selected for evaluating and regionalizing the water environmental capacity by ArcG1S spatial analysis, including geomor- phologic characteristics, water quality goals, water body accessibility, water-dilution channels, and current water quality. Then, the spa- tial optimization of agriculture and industry was adjusted through overlay analysis, based on the balance between industrial space and water environmental capacity. The results show that the water environmental capacity gradually decreases from the west to the east, in contrast, the pollution caused by industrial and agricultural clustering is distributes along Taihu Lake, Gehu Lake and urban districts. The analysis of the agricultural space focuses on optimizing key protected areas of the Taihu Lake Basin, and the shores of Gehu Lake, optimally adjusting the second protected areas of the Taihu Lake Basin, and generally adjusting the urban areas of Changzhou and Wuxi cities. The analysis of industrial space focuses on optimizing the downtowns of Changzhou and Wuxi cities, optimally adjusting key protected areas and second protected areas of the Taihu Lake Basin, and generally adjusting the south and southwest of Gehu Lake. Lastly, some schemes of industrial and agricultural layouts and policies for the direction of industrial and agricultural development were proposed, reflecting a correlation between industry and agriculture and the water environment.

Reverse Logistics Related to Waste Management with Emphasis on Developing CountriesmA Review Paper

This paper provides an overview of the state of art of reverse logistics and current status of waste management problems with special emphasis on developing countries. Logistics activities have been practiced and played a fundamental role in the global economic development for over 5,000 years. It has then been transformed into different logistics branches and elaborates the emergency of reverse logistics as one of the most important. The paper presents the evolution of logistics into reverse logistics and how it relates to waste management both in the developed and developing world. Reverse logistics is a relatively new phenomenon in the research area which is mainly referring to damaged goods, the take back of products that should be returned to the manufacturers or distributors. Reverse logistics is relatively more practiced in an organized way in the developed world than in the developing countries in that the latter provided less value additions on reversed products.

The study of metal cycles in China

A model of Fe-flow in the life cycle of steel product was put forward and analyzed. Three important resource and environmental indicators for Fe-flow analysis,that is,steel scrap index,iron ore index and iron loss index were derived from this model. Illustrative examples,demonstrating the influence of the variation of steel output on steel scrap index and iron ore index were given. Case studies for estimating the values of steel scrap index of Japan,China and USA in the period of 1988-1997 were carried out. It was clarified that the main reason of severe deficiency in steel scraps for China's steel industry was its continued rapid growth. The study of iron,copper,zinc and lead cycle in China was carried out successfully according to this model.