双套管长距离气力输送技术的应用

介绍了北仑发电厂5×600 MW机组烟气脱硫项目石灰石粉双套管长距离气力输送工程的系统设计、安装、调试、运行等情况,并分析了该系统的主要特点.     

焦粉活性炭的制备及其应用

用废弃焦粉制备焦粉活性炭，通过正交实验考察了各种因素对焦粉活性炭性能的影响。实验结果表明：在活化时间80min、活化温度900℃、碱炭比（氢氧化钾与废弃焦粉的质量比）4、废弃焦粉粒径小于0．05mm的最佳条件下，制备的焦粉活性炭的亚甲基蓝吸附值为304．8mg／g，产率为35．6％；废弃焦粉的活化是活化剂刻蚀其颗粒形成丰富孔结构的氧化还原反应过程；用最佳条件下制备的焦粉活性炭处理质量浓度为60mg／t．的模拟含Cr^6＋废水，在废水pH为3—4、焦粉活性炭加入量为4g/L、吸附时间为50min的条件下，Cr^6＋去除率达93．2％。     

超音速气流粉碎机生产超细粉体的安全问题探讨

超音速气流粉碎机是一种常用的生产超细粉体的设备。粉碎过程中涉及到许多安全问题，如粉尘的危害，噪音危害等。本文根据安全系统工程理论。从除尘器的选择、防护和管理措施的实施等方面对治理粉尘危害进行了探讨。     

Synthesis of highly effective absorbents with waste quenching blast furnace slag to remove Methyl Orange from aqueous solution

Water quenching blast furnace slag(WQBFS) is widely produced in the blast furnace iron making process. It is mainly composed of CaO, MgO, Al_2O_3, and SiO_2 with low contents of other metal elements such as Fe, Mn, Ti, K and Na. In this study, WQBFS was treated with grinding, hydrochloric acid acidification, filtration, filtrate extraction by alkali liquor and a hydration reaction. Then BFS micropowder(BFSMP), BFS acidified solid(BFSAS) and BFS acid-alkali precipitate(BFSAP) were obtained, which were characterized by X-ray diffraction, scanning electron microscopy, X-ray fluorescence and Brunauer-Emmet-Teller(BET)specific surface area. The decoloration efficiency for Methyl Orange(MO) was used to evaluate the adsorptive ability of the three absorbents. The effects of adsorptive reaction conditions(p H and temperature of solution, reaction time, sorbent dosage and initial concentration) on MO removal were also investigated in detail. The results indicated that BFSAP performed better in MO removal than the other two absorbents. When the p H value of MO solutions was in the range 3.0–13.0, the degradation efficiency of a solution with initial MO concentration of 25 mg/L reached 99.97% for a reaction time of 25 min at 25°C.The maximum adsorption capacity of BFSAP for MO was 167 mg/g. Based on optimized experiments, the results conformed with the Langmuir adsorption isotherm and pseudo-second-order kinetics. Among inorganic anions, SO_4~(2-)and PO_4~(3-)had significant inhibitory effects on MO removal in BFSAP treatment due to ion-exchange adsorption.     

Characteristics of mercury emission from linear type of spent fluorescent lamp

In order to recycle the linear type of SFL (spent fluorescent lamp), mercury from SFL should be controlled to prevent leaking into the environment. For mercury emission from SFL, mercury concentration is estimated in the parts of SFL such as glass tube, phosphor powder, and base cap using the end-cutting unit. It is also evaluated mercury emission in the effluent gas in the end-cutting unit with changing flow rate. From the results of mercury emission from SFLs, phosphor powder has greater than 80% of mercury amount in SFL and about 15% of mercury amount contained in glass tube. The initial mercury concentration in vapor phase is almost decreased linearly with increasing airflow rate from 0.7 L/min to 1.3 L/min. It is desirable that airflow rate should be high until the concentration of mercury vapor will be stable because the stabilized concentration becomes to be low and the stabilized time goes to be short as increased airflow rate. From KET and TCLP results, finally, phosphor powder should be managed as a hazardous waste but base-cap and glass are not classified as hazardous wastes.     

Pyrolysis characteristics of the mixture of printed circuit board scraps and coal powder

Thermogravimetric (TG) analysis and infrared spectroscopy were used to analyze the pyrolysis characteristics of printed circuit board scraps (PCBs), coal powder and their mixtures under nitrogen atmosphere. The experimental results show that there is a large difference between waste PCBs and coal powder in pyrolysis processing. The pyrolysis properties of the mixing samples are the result of interaction of the PCBs and coal powder, which is influenced by the content of mixture. The degree of pyrolysis and pyrolysis properties of the mixture are much better than that of the single component. The TG and the differential thermogravimetric (DTG) curves of the PCBs mixed with coal powder move towards the high-temperature zone with increasing amount of coal powder and subsequently the DTG peak also becomes wider. The Coats–Redfern integral method was used to determine the kinetic parameters of pyrolysis reaction mechanism with the different proportion of mixture. The gas of pyrolysis mainly composes of CO₂, CO, H₂O and some hydrocarbon. The bromide characteristic absorption peak has been detected obviously in the pyrolysis gas of PCBs. On the contrary, the absorption peak of the bromide is not obvious in pyrolysis gas of the PCBs samples adding 40% coal powder.     

Recovery of yttrium from fluorescent powder of cathode ray tube,CRT: Zn removal by sulphide precipitation

This work is focused on the recovery of yttrium and zinc from fluorescent powder of cathode ray tube (CRT). Metals are extracted by sulphuric acid in the presence of hydrogen peroxide. Leaching tests are carried out according to a 2² full factorial plan and the highest extraction yields for yttrium and zinc equal to 100% are observed under the following conditions: 3 M of sulphuric acid, 10% v/v of H₂O₂ concentrated solution at 30% v/v, 10% w/w pulp density, 70 °C and 3 h of reaction.Two series of precipitation tests for zinc are carried out: a 2² full factorial design and a completely randomized factorial design. In these series the factors investigated are pH of solution during the precipitation and the amount of sodium sulphide added to precipitate zinc sulphide. The data of these tests are used to describe two empirical mathematical models for zinc and yttrium precipitation yields by regression analysis. The highest precipitation yields for zinc are obtained under the following conditions: pH equal to 2–2.5% and 10–12% v/v of Na₂S concentrated solution at 10% w/v. In these conditions the coprecipitation of yttrium is of 15–20%.Finally further yttrium precipitation experiments by oxalic acid on the residual solutions, after removing of zinc, show that yttrium could be recovered and calcined to obtain the final product as yttrium oxide. The achieved results allow to propose a CRT recycling process based on leaching of fluorescent powder from cathode ray tube and recovery of yttrium oxide after removing of zinc by precipitation. The final recovery of yttrium is 75–80%.     

聚烯烃工业粉尘静电爆炸的危险与应对策略

随着我国聚烯烃粉体生产的迅猛发展,粉体生产过程中的静电爆炸事故也相应增多。该文介绍了国外粉尘静电爆炸研究的进展和国内粉尘静电爆炸事故的主要现象。近期国外的研究特点主要是逐渐采用工业规模的实验装置取代实验室的基础研究,着重开展了料仓放电的危险研究和与放电燃爆有关的基础研究,包括安全评价和工业控制条件的推荐研究。国内粉尘静电爆炸事故主要存在的现象有设计缺欠或不合理,装置扩能改造时忽视了脱挥或通风的配套改造,处理不合格料或过渡时应急处理不当,操作失误或不规范,破坏料仓通风控制,料位计选型不当,增加高能放电引燃几率。针对分析出的问题和现象,文章提出了查清运行装置的具体事故隐患,进行防止聚烯烃料仓粉尘静电爆炸的可接受研究和可操作性研究,开展粉尘静电爆炸的危险教育,提高员工的安全意识和应急处理能力等应对策略。     

ABC干粉抑制瓦斯爆炸的实验研究

为测定ABC干粉对瓦斯爆炸的抑制作用,采用容积为20L的近球形抑爆实验系统,粒径为20.76μm,主要成分为高聚合度磷酸铵盐的ABC干粉进行瓦斯抑爆实验。实验结果表明：ABC干粉的添加能够降低瓦斯爆炸的压力;粉体浓度为0.10g/L时,抑爆效果最好;粉体的抑爆效果,不仅与粉体浓度有关,还与爆炸性混合气体中的甲烷浓度有关;点火延迟时间越长,粉体抑爆效果越差。     

凝结水精处理技术的应用及发展

概述了凝结水精处理技术的国内外发展现状及主要工艺,对国内外主要系统供应商的技术特点进行了分析总结。