Dechlorination Behavior of Mixed Plastic Waste by Employing Hydrothermal Process and Limestone Additive

The usage of plastic-impregnated waste derived solid fuel in conventional combustor is hindered by many technical factors, especially its organic chlorine content. In this paper, experimental study of hydrothermal treatment on mixed plastic waste using the mixture of polypropylene, polystyrene, polyethylene and polyvinyl chloride （PVC） has been performed to observe the dechlorination effect of hydrothermal treatment on the waste. The system was generally applying saturated steam at around 2.4 MPa in a stirring reactor for about 90 minutes. After undergoing the process, the organic chlorine in treated plastic waste was reduced to 1,700 ppm level while the inorganic chlorine content was increased, suggesting an organic chlorine conversion phenomenon to inorganic chlorine, accompanied with low pH due to dehydrochlorination process. Additional limestone （Ca（OH）2） in subsequent experiment showed that the similar phenomenon was occurred but with higher pH and lower chlorine content in the condensed water, suggesting the production of inorganic salt rather than hydrochloric acid. Laboratory scale experiment was also performed to confirm the dechlorination phenomena especially for PVC, and the result showed that the main parameter which affected the dechlorination phenomena was the amount of water in hydrothermal process rather than limestone addition. It is suggested that a combination ofhydrothermal process and alkali addition would produce a low-chlorine solid product from plastic waste, promoting its usage as alternative solid fuel.

Process Development and Design of Chlorine Dioxide Production Based on Hydrogen Peroxide

This paper presents a process development and design of chlorine dioxide production based on hydrogen peroxide. The process is characterized by cleaner production, high efficiency, and waste minimization. Optimization of process conditions, selection of equipment, and experiment of recycle of waste acid are carried out. The process design is realized in consideration of several aspects such as operation, material, equipment design and safety. An industrialized process flowsheet is developed according to experiment. A pilot testing is carried out to confirm the lab results. Process design of chlorine dioxide production based on hydrogen peroxide is realized.

UV-Based Advanced Oxidation Processes for Antibiotic Resistance Control: Efficiency, Influencing Factors, and Energy Consumption

Antibiotic resistant bacteria(ARB)with antibiotic resistance genes(ARGs)can reduce or eliminate the effectiveness of antibiotics and thus threaten human health.The United Nations Environment Programme considers antibiotic resistance the first of six emerging issues of concern.Advanced oxidation processes(AOPs)that combine ultraviolet(UV)irradiation and chemical oxidation(primarily chlorine,hydrogen peroxide,and persulfate)have attracted increasing interest as advanced water and wastewater treatment technologies.These integrated technologies have been reported to significantly elevate the efficiencies of ARB inactivation and ARG degradation compared with direct UV irradiation or chemical oxidation alone due to the generation of multiple reactive species.In this study,the performance and underlying mechanisms of UV/chlorine,UV/hydrogen peroxide,and UV/persulfate processes for controlling ARB and ARGs were reviewed based on recent studies.Factors affecting the process-specific efficiency in controlling ARB and ARGs were discussed,including biotic factors,oxidant dose,UV fluence,pH,and water matrix properties.In addition,the cost-effectiveness of the UV-based AOPs was evaluated using the concept of electrical energy per order.The UV/chlorine process exhibited a higher efficiency with lower energy consumption than other UV-based AOPs in the wastewater matrix,indicating its potential for ARB inactivation and ARG degradation in wastewater treatment.Further studies are required to address the trade-off between toxic byproduct formation and the energy efficiency of the UV/chlorine process in real wastewater to facilitate its optimization and application in the control of ARB and ARGs.

降温过程中NaCl盐渍土相变的电化学特征

氯盐渍土是中国西北寒旱区一种典型的盐渍土类型,其电化学特征是深入理解盐渍土腐蚀病害机理的关键。为探究盐渍土孔隙溶液相变与其电化学特征之间的联系,以NaCl盐渍粉质黏土为研究对象,测试了不同含盐量和温度条件下NaCl盐渍土的电化学阻抗谱。研究表明:NaCl盐渍土阻抗随着测试频率的增加而逐步降低,并在高频率时逐步达到稳定。NaCl盐渍土的阻抗模的对数值在冻结前随温度的降低线性增加,而在冻结后,冰晶和盐结晶的生成导致土体阻抗模值发生显著增加。NaCl盐渍土在冻结前表现为一段容抗弧,而在冻结后,由相变导致的土体水盐迁移使得土体在出现阻抗弧后又存在一段扩散阻抗。根据土体在冻结前后的导电路径,建立了土体在冻结前后的等效电路模型,并在此基础上分析了土体孔隙溶液相变与对应电路元件之间的联系。此研究对深入理解盐渍土电化学特征及孔隙溶液相变规律具有重要意义。

含氟氯氧化锌烟尘的梯级处理工艺试验研究

针对氧化锌冶炼烟尘中氟氯含量高,直接返回系统易导致阴阳极板腐蚀、电积锌质量差等问题,研究了采用“酸浸—石灰一次中和除氟—石灰二次中和沉锌”梯级处理工艺从氧化锌冶炼烟尘中回收锌。结果表明:在浸出温度80℃、浸出终点pH=1.0、液固体积质量比4/1、浸出时间1 h优化工艺条件下,Zn、F、Cl浸出率分别为96.15%、95.26%、97.44%;用石灰调节酸浸液沉淀反应终点pH至5.2时,氟沉淀率为95.17%,而锌损失率仅为1.73%;用石灰二次调节除氟后液沉淀反应终点pH为8.0时,锌全部沉淀,所得中和渣中锌质量分数为24%左右;全流程工艺的氟、氯脱除率分别约为92%、97%,锌回收率>90%,同时铅、银可进入酸浸渣中加以回收。该工艺可实现危害元素氟、氯的高效脱除,以及锌、铅、银的有效回收,具有一定推广价值。

半导体级高纯石英砂纯化装备及工艺研究

目前我国高纯石英砂大量依赖进口,且高品质石英原矿进口受到国外企业限制,因此迫切需要解决我国石英砂提纯技术落后的现状。本研究通过对石英砂提纯技术和杂质进行分类总结,自主研发了石英砂纯化装备,提出了一种新型石英砂纯化工艺:真空焙烧-氯化焙烧联合提纯法。结果表明,随着温度升高,工艺过程压力减小,杂质含量不断减少,纯化效果越显著。温度为1300℃,工艺过程压力为10 Pa,石英砂纯化效果最佳,碱金属元素Li、Na、K去除率分别达到95.24%、97.92%、96.61%,较难去除的Al和Ti元素含量也有所降低,杂质总含量从12.60×10^(-6)降至7.25×10^(-6),去除率达到42.46%,同时对石英砂内部气液包裹体也有明显去除效果,石英砂纯度等级从4N8级提纯至5N2级,达到半导体级高纯石英砂的标准。

Chlorinated butyl rubber/two-step modified montmorillonite nanocomposites:Mechanical and damping properties

Montmorillonite(MMT) was modified by ultrasound and castor oil quaternary ammonium salt intercalation method to prepare a new type of organic montmorillonite(OMMT). The surface structure, particle morphology, interlayer distance, and thermal behavior of the samples obtained were characterized. The modified OMMT was then added to chlorinated butyl rubber(CIIR) by mechanical blending, and a composite material with excellent damping properties was obtained. The mechanical experiment results of CIIR nanocomposites showed that the addition of OMMT improved their tensile strength, hardness,and stress relaxation rate. Compared with pure CIIR, when the content of OMMT was 5 phr(part per hundred of rubber), the tensile strength of the nanocomposite was increased by 677% and the elongation at break was also increased by 105.4%. The enhancement of this performance was mainly due to the dispersion of the nanosheets in CIIR rubber and the chemical interaction between the organoclay and the polymer matrix, which was confirmed by morphology and spectral analysis. OMMT also endowed a positive effect on the damping properties of CIIR nanocomposites. After adding 5 phr of OMMT, the nanocomposite owned the best damping performance, and the damping factor, tanδmax, was 37.9% higher than that of pure CIIR. Therefore, the good damping and mechanical properties of these CIIR nanocomposites provided some novel and promising methods for preparing high-damping rubber in a wide temperature range.

Chlorine drying with hygroscopic ionic liquids

The chlorine(Cl2)drying technology using ionic liquids(ILs)as absorbents was proposed for the first time and systematically investigated from the molecular level scaled up to the industrial level.The hygroscopic IL[EMIM][CH3SO3]was screened as a suitable absorbent from 238 potential IL candidates consisting of 14 cations and 17 anions,by calculating the Cl2 and H2O solubility and separation selectivity of Cl2 to H2O in different ILs based on the COSMO-RS model.The microscopic atomic and molecular insights into the separation mechanisms were deeply revealed by using COSMO-RS model analyses(i.e.,σ-profiles,σ-potentials,excess enthalpies,entropies,and Gibbs free energies)and quantum chemistry calculation(binding energies and weak interaction analyses).The Cl2 solubility in pure IL and H2O+IL systems were predicted by the COSMO-RS model,and the results agree with the microscopic mechanism identification.Moreover,the strict equilibrium stage model employed with the COSMO-RS model parameters was built to perform the process simulation,and continuous Cl2 drying with ILs was conceptually designed and optimized at industrial scale.It was confirmed that[EMIM][CH3SO3]is a very promising absorbent leading to a less IL amount,a much lower energy consumption than the other IL[EMIM][BF4],which has a very bright industrialization potential used for Cl2 drying technology.

Removal of TOC and Color in Bleaching Effluents from Straw Pulp and Paper Mill by Fe^0-H_2O_2 Process

TOC and color in the bleaching effluent from straw pulp paper process could not reach draining standard after its treatment by a biochemical process. In this study, advanced treatment by integrated micro-electrolysis （Fe^0） method and Fenton-like process was investigated under various conditions, i.e. pH, Fe/C ratio, initial I-I2O2 concentration and carrier gas. Results showed that Fe/C ratio（V/V = 1.5）, larger H2O2 dosage around 50 rag/L, lower pH（pH= 3） turned out to be particularly efficient. Temperature was a key parameter, remarkably increasing reaction rates. Carrier air not only improved reaction efficiency, but also saved H2O2 dosage. Chlorinated organic compounds could be reductive dechlorinated by Fe^0 reaction and oxidated by OH produced from Fenton process. The combination of Fe^0 and H2O2 reactions had been proved to be highly effective for the advanced treatment of such a type of wastewaters, and important advantages concerning the application in the study.

Optimization of Hydrothermal Treatment Parameters to Produce Chlorine-Free Alternative Solid Fuel from Plastic-Contained Municipal Solid Waste

An experimental study of the treatment of plastic-contained Japanese MSW （municipal solid waste） employing 1 ton capacity hydrothermal reactor to produce chlorine-free solid fuel has been performed. The system applies medium-pressure saturated steam at about 2 MPa in a stirred reactor for certain holding period. It was shown that the products exhibited organic chlorine conversion into inorganic chlorine, which can then be water washed. To obtain an optimal operating condition, the temperature and holding period was integrated into one parameter called RS （reaction severity）. It was found that to convert 75% organic chlorine in the MSW, the optimum RS number correlates to an operating temperature of about 225℃ and holding period of 90 min, or 235 ℃ for 60 min. Since hydrothermal treatment is a batch process, a shorter holding period is preferable to increase the number of batches and indirectly increase its processing capacity.

基于粒子群优化模糊PID控制的水厂加氯系统

水厂加氯过程具有非线性、大时滞等特点,采用传统的PID控制方式难以实现消毒剂精准投加。因此,以某采用次氯酸钠消毒系统的水厂为例,首先通过分析该水厂加氯系统工作原理,结合工程经验和运行数据确定了加氯过程的近似数学模型。然后综合使用粒子群优化算法、模糊控制算法和PID控制算法,设计了一种粒子群优化模糊PID控制器,并利用MATLAB软件搭建了粒子群优化模糊PID控制系统和传统PID控制系统的模型进行仿真验证,结果表明:相较于传统PID控制系统,粒子群优化模糊PID控制系统的超调量减少了89.36%,调节时间减少了46.63%,其抗干扰能力也更强,系统整体控制效果有了较大提升。最后使用基于粒子群优化的模糊PID控制法对水厂加氯控制系统进行改造,试运行后发现,新系统控制效果良好,出厂水游离氯值能够稳定在设定值附近。

天然鳞片石墨提纯研究进展

天然鳞片石墨是一种战略资源,对国民经济发展及现代化建设具有重要作用。石墨材料因其具有导电、耐热、抗腐蚀、韧性好、润滑性能好等优异性能,被广泛应用于密封、铸造、防火材料、导电材料等传统工业领域,在新能源、电子信息技术、高端装备技术等新兴领域也具有潜在的应用价值,被誉为“工业黑金”。虽然我国有着丰富的石墨资源,但由于石墨提纯技术落后,石墨深加工产品与国外仍有一定差距。石墨材料纯度越高其应用价值越高,因此,研究高效、节能的石墨提纯技术对我国石墨产业的发展具有十分重要的意义。目前,常用的石墨提纯方法可分为物理提纯法和化学提纯法,其中,物理提纯法包括浮选法、高温法,化学提纯法包括氢氟酸法、酸碱法和氯化焙烧法。分析对比了这几种提纯方法的原理、优点及存在的问题。未来的研究方向主要集中在对单一提纯方法的工艺流程、提纯设备的优化,多种方法联合使用,以及新方法的开发及应用等方面。

攀西钛资源综合利用技术应用现状及发展方向

我国四川省攀西地区钒钛磁铁矿资源中钛资源储量巨大,主要以钛精矿形式回收利用,并主要用于硫酸法钛白和酸溶性钛渣生产原料,其产量占全国钛原料市场的75%以上。硫酸法钛白工艺技术成熟,已形成相对完整的“内循环”,但尚未全面突破硫酸法钛白联产技术;电炉冶炼酸溶性钛渣工艺技术较成熟,主流工艺是钛精矿不预处理-实心圆形电极-密闭圆形电炉连续冶炼工艺,钛精矿酸性氧化球团-电炉冶炼一步法工艺、大功率矩圆形电炉冶炼酸溶性钛渣等钛渣新工艺发展较快、发展空间大,是今后主要发展方向。目前攀西地区发展钛产业的一个主要问题是缺乏沸腾氯化法钛白工艺需求的高品位钛资源,未来需要突破攀西高钙镁钛精矿除杂提质制取高品位高钛渣关键核心技术,并同时研发攻关硫酸法钛白附产绿矾和钛石膏回收循环利用技术、高炉钛渣提钛及综合利用技术、钒钛铁精矿非高炉炼铁新技术,以及以钛精矿、钛渣或钛白粉为原料制备含钛及钛基新材料技术,以期获得攀西钛产业的健康可持续发展。

原油中有机氯化物分布转化情况及危害性研究进展

原油中天然存在的有机氯化物含量通常较低。随着油田进入开采中后期,原油重质化、劣质化加剧,为提高原油采收率使用了一些含氯化学助剂,导致原油中有机氯化物含量增加。了解有机氯化物在原油中的组成、分布、石油加工中的转移/转化以及危害机理至关重要。不同原油中的有机氯化物在馏分油中有着不同的分布规律,且轻馏分中的有机氯化物类型多为氯代烷烃、氯代烯烃、氯代苯及氯代苯胺等,随着原油重质化程度的增加,有机氯化物也逐渐富集于重质馏分油中,其形态也由此变得复杂。有机氯化物无法在原油脱盐脱水工段有效去除,会随着原油进入后续加工工段并产生不良影响。综述了有机氯化物在原油常减压蒸馏、催化裂化和催化加氢等加工过程中的转移和转化情况,其中发生的裂解、水解和加氢等反应会生成腐蚀性产物氯化氢,其在原油加工过程中会对设备造成腐蚀,也会导致管路堵塞及催化剂中毒等严重危害。本文对3个方面的危害进行了机理分析,并阐述了其研究现状。结果表明:有机氯化物会形成酸性腐蚀环境腐蚀设备、形成铵盐结晶堵塞管路、破坏催化剂金属活性位使催化剂失活,对炼油过程造成一定程度影响。

Process Optimization and Reaction Mechanism of Removing Copper From an Fe-Rich Pyrite Cinder Using Chlorination Roasting

The aim is to remove copper from a pyrite cinder by optimizing the chlorination roasting process using re-sponse surface methodology （RSM） and the reaction mechanism of chlorination roasting based on thermodynamic calculation was discussed. A quadratic model was suggested by RSM to correlate the key parameters, namely, dos-age of chlorinating agent, roasting temperature and roasting time to the copper volatilization ratio. The results indi- cate that the model is well consistent with the experimental data at a correlation coefficient （R2） of 0.95, and the dosage of chlorinating agent and roasting temperature both have significant effects on the copper volatilization ratio. However, a roasting temperature exceeding 1170 ~C decreases the volatilization ratio. The optimum conditions for removing copper from the cinder were identified as chlorinating agent dosage at 5%, roasting temperature at i155.10 ℃ and roasting time of 10 min; under Such a conditiom a copper volatilization ratid of 95.16% Was a- chieved from the cinder. Thermodynamic calculation shows that SiO2 in the pellet plays a key role in the chlorine re-lease from calcium chloride, and the chlorine release reactions cannot occur without it.

含氯烟气净化并副产无铁盐酸的工艺设计

在氯碱化工生产过程中,氯乙烯(VCM)和聚氯乙烯(PVC)等装置会产生含氯有机废气。目前,工业上主要采用焚烧技术对含氯有机尾气进行处理,该技术可将有机物分解成二氧化碳和水,并产生含氯的无机烟气。含氯烟气经过净化处理后进行排放,同时副产出低附加值的含铁工业盐酸。本文通过设计含氯烟气净化并副产无铁盐酸的工艺流程,通过Aspen Plus软件对该流程进行模拟计算验证,目的是提升工业盐酸的品质,降低装置的运行成本。

钛白粉副产硫酸亚铁的综合利用现状

钛白粉的两种制备方法硫酸法与氯化法在我国应用程度与范围不同,硫酸法是我国主流的生产工艺。硫酸法生产会产出大量废气、废水、废渣与副产物,对环境造成严重污染。硫酸亚铁作为硫酸法制备钛白粉工艺的主要副产物,对其进行妥善处理和利用具有极高经济价值与环境效益。基于两种制备工艺的不同,通过对比硫酸法与氯化法的优缺点,对硫酸法副产物硫酸亚铁的综合利用进行了总结,包括直接销售使用与加工后销售使用两个方面,并对钛白粉未来发展进行展望。

磺酰氯促进金属氯化物插层石墨以实现高效钠存储

金属氯化物-石墨插层化合物具有导电性优异,石墨层间距大等特点,可用作钠离子电池负极材料。然而,在传统金属氯化物插层石墨过程中,不可避免地用到氯气,既增加了实验操作的风险,也对实验设备提出更高要求。基于上述原因,本文创新性地使用SO_(2)Cl_(2)作为氯源来促进BiCl_(3)插层石墨。该方法不仅有效提高了BiCl_(3)插层效率,也避免了直接使用氯气带来的安全性风险。采用该方法所合成的三氯化铋-石墨插层化合物(BiCl_(3)-GICs)的层间距为1.26 nm,BiCl_(3)插层含量高达42%。以其为负极材料,组装的钠离子电池具有高的比容量(213 mAh g^(-1)at 1 A g^(-1))和优异的倍率性能(170 mAh g^(-1)at 5 A g^(-1))。此外,原位拉曼光谱测试结果表明,首圈放电后石墨与插层的BiCl_(3)相互作用减弱,该过程有效促进了钠离子在石墨层内的存储。采用该方法可成功制备多种类型金属氯化物-石墨插层化合物,为开发高性能储能材料提供了可行思路。

DBP formation from degradation of DEET and ibuprofen by UV/chlorine process and subsequent post-chlorination

The formation of disinfection by-products（DBPs） from the degradation of N,N-diethyl-3-methyl benzoyl amide（DEET） and ibuprofen（IBP） by the ultraviolet irradiation（UV）/chlorine process and subsequent post-chlorination was investigated and compared with the UV/H_2O_2 process.The pseudo first-order rate constants of the degradation of DEET and IBP by the UV/chlorine process were 2 and 3.1 times higher than those by the UV/H_2O_2 process, respectively, under the tested conditions. This was due to the significant contributions of both reactive chlorine species U（RCS） and hydroxyl radicals（HO） in the UV/chlorine process. Trichloromethane, 1,1,1-trichloro-2-propanone and dichloroacetic acid were the major known DBPs formed after 90% of both DEET and IBP that were degraded by the UV/chlorine process. Their yields increased by over 50%after subsequent 1-day post-chlorination. The detected DBPs after the degradation of DEET and IBP comprised 13.5% and 19.8% of total organic chlorine（TOCl）, respectively, and the proportions increased to 19.8% and 33.9% after subsequent chlorination, respectively. In comparison to the UV/H_2O_2 process accompanied with post-chlorination, the formation of DBPs and TOCl in the UV/chlorine process together with post-chlorination was 5%–63% higher,Ulikely due to the generation of more DBP precursors from the attack of RCS, in addition to HO.