轧钢酸洗废液制备聚合氯化铁的工艺条件研究

利用轧钢酸洗废液制备出一种新型高效的无机高分子絮凝剂-聚合氯化铁,进行了合成条件研究。研究结果表明利用酸洗废液制备聚合氯化铁的反应条件:反应温度控制在常温,废液中二价铁与氧化剂氯酸钠的物质的量的比为1∶0.08,每100mL酸洗废液加入17 mL浓盐酸,反应时间在5 min。所制得的聚合氯化铁产品,总铁含量大于40%,盐基度为58.7%,密度为1.3g/mL。     

基于Aspen Plus的MSW气化熔融工艺全流程模拟研究

城市固体废物（MSW）气化熔融工艺能够减少二噁英的生成和熔融固化重金属,是一种清洁高效的固体废物处理方式。已有研究多针对MSW的热解特性以及污染物的生成与排放,而对气化熔融工艺系统模块之间的影响和各反应器间物质流、能量流的联动变化过程研究不足。利用Aspen Plus模拟平台,基于吉布斯自由能最小化原理,对MSW气化熔融工艺进行了全流程模拟研究,分析了垃圾干燥温度、垃圾含水率、气化温度、气化介质以及灰熔点对工艺流程节点参数、物质流和能量流的影响,并提出了优化的工艺流程和运行参数。结果表明：在垃圾热解模拟时,垃圾含水率为9%,通过烟气循环能达到能量自给;在相同条件下,以水蒸气作为气化介质的气化效率最高,且在气化温度为850 ℃,水蒸气当量比为50%时,达到最佳工艺效果;当气化后产生的焦炭在熔融炉内燃烧刚满足灰熔点温度时,灰熔点的升高使气化剂比例、气化气有效气体摩尔流量和碳转化率不断降低。不同工况下的物质流、能量流的变化对实际工程具有指导意义。

     

城市垃圾的再利用

根据我国垃圾处理的现状，阐述了我国城市垃圾再利用的意义并介绍了几种垃圾组分再利用的途径和技术，提出了促进城市垃圾再利用的一些对策。     

废弃印刷线路板熔融盐气化特性研究

在熔融盐气化炉中进行废弃印刷线路板气化实验,考察了空气当量比对气体产率、气体热值、碳转化率以及气化效率的影响,并对N2气氛下线路板在熔融盐反应器中裂解液体产物通过气质联用仪进行了分析.结果表明,气体产率和碳转化率随着空气当量比增加而增加,空气当量比增加到40%时,气体产率和碳转化率分别达到840 mL·g-1和96%;气体产物热值随着空气当量比增加而减少,气化效率随着空气当量比的增加先增加然后减少,在20%空气当量比气化效率达到最大值94%.液体产物的主要成分为苯酚、2-甲基苯酚、萘等,表明线路板在熔融盐气化炉内的反应过程中,苯环结构上的长链烷烃脂肪烃支链得到脱除,苯基C6H5-O的断裂得到加强,同时发生芳构化反应.     

味精生产的污染排放分析与治理研究

以东北地区某味精生产厂为例,对味精生产从水体、大气、固废三个方面进行了污染分析。通过对污水处理和大气污染治理的系统控制以及对固体废弃物的综合利用研究,结果表明,味精生产中污染排放能够达到国家的相关标准。     

废弃印刷电路板资源化回收利用技术探讨

废弃印刷电路板成分复杂,在含有大量可回收金属的同时,还含有多种有害物质,其资源化回收和处置技术受到国内外广泛的关注。对目前主要的废弃印刷电路板回收利用技术应用状况和实践进展进行了分析。机械法．化学冶金法是目前广泛应用的以回收废弃印刷电路板中的金属为主要目的的回收技术。应用热解技术处理废弃印刷电路板,不仅可以有效回收废弃印刷电路板中的金属物质,还可以使废弃印刷电路板中的非金属物质得到资源化利用,具有很好的发展前景。     

等离子体热解气化有机废弃物制氢的关键技术分析

等离子体热解气化有机固体废物制氢是一种先进高效的废物处理及资源化利用技术.首先,本文讨论了等离子体热解气化有机废弃物的机理,也概括了等离子体发生器的类型及其特点,其次分析了等离子体处理固体废弃物的影响因素,认为输入功率和载气类型等是影响等离子体处理的主要因素,最后总结了等离子体处理医疗垃圾、农林生物质、污泥等的应用现状与前景,指出等离子体热解气化固体废弃物是一种很有潜力的制氢方法.     

A strategy for enhancing anaerobic digestion of waste activated sludge: Driving anodic oxidation by adding nitrate into microbial electrolysis cell

Cathodic reduction of CO₂ and anodic oxidation of organic matters are crucial to methane-producing microbial electrolysis cell (MEC) applied in anaerobic digestion of waste activated sludge. However, cathodic CO₂ reduction is usually restrained by slow metabolism rates of H₂-utilizing methanogens and low electron-capturing capacity of CO₂, which consequently slows down the anodic oxidation that participates to sludge disintegration. Herein, a strategy with adding nitrate as electron acceptor to foster electronic transfer between the anode and cathode was proposed to improve anodic oxidation. Results showed that the average efficiency of anodic oxidation in the nitrate-added MEC increased by 55.9%. Accordingly, volatile suspended solid removal efficiency in the nitrate-added MEC was 21.9% higher than that of control MEC. Although the initial cumulative methane production in the nitrate-added MEC was lower than that of control MEC, the cumulative methane production in 24?days was 8.9% higher. Fourier transform infrared spectroscopy analysis indicated that anodic oxidation of MEC with nitrate accelerated the disintegration of sludge flocs and cell walls. Calculation on current signal further revealed that anodic oxidation driven by cathodic nitrate reduction was the main mechanism responsible for the improved sludge digestion.     

Effect of Ca:Mg ratio and high ammoniacal nitrogen on characteristics of struvite precipitated from waste activated sludge digester effluent

This study revealed the relationship between the presence of calcium impurities and ammoniacal nitrogen concentration upon crystallization of struvite. The research hypothesis was that the presence of both calcium and high concentrations of ammoniacal nitrogen(328–1000 mg/L) in waste activated sludge may influence the struvite quality and acid stability. Hence, we studied the impact of Ca:Mg ratio upon morphology, particle size, purity and dissolution of struvite, in the presence of varying levels of excess ammoniacal nitrogen. X-ray diffraction revealed that up to 31.4%amorphous material was made which was assigned to hydroxyapatite. Increasing the ammoniacal nitrogen concentration and elevation of the Mg:Ca ratio maximized the presence of struvite. Struvite particle size was also increased by ammoniacal nitrogen as was twinning of the crystals. Tests with dilute solutions of organic acid revealed the sensitivity of struvite dissolution to the physical characteristics of the struvite. Smaller particles(21.2 μm) dissolved at higher rates than larger particles(35.86 μm). However,struvite dissolved rapidly as the p H was further reduced irrespective of the physical characteristics. Therefore, addition of struvite to low p H soils was not viewed as beneficial in terms of controlled nutrient release. Overall, this study revealed that waste activated sludge effluent with high ammoniacal nitrogen was prospective for synthesis of high quality struvite material.     

物联网技术在城市生活垃圾收运系统中的应用

我国的城市生活垃圾收运系统因其回收率低,监管难等问题,一直受到社会的广泛关注,而物联网技术因其可追溯性、动态性等特点,在解决该问题上表现出其显著优势。简要介绍了物联网技术的作用及其应用领域,总结了国内外基于物联网技术的城市生活垃圾收运情况,以我国上海市餐厨垃圾收运情况为案例,对其现状和目前存在的问题进行了总结,并结合物联网技术对餐厨垃圾信息化收运的管理方法进行了展望。