含油污泥与配合煤共热解煤焦的微观结构与气化反应特性

以含油污泥与配合煤为原料在850-1150℃热解制得焦样,采用N₂吸附-脱附和X射线衍射(XRD)分析煤焦孔隙结构及碳微晶结构,并运用热重分析(TGA)考察热解温度和含油污泥添加量对煤焦气化反应活性的影响。结果表明,提高热解温度和添加含油污泥能促进煤焦形成更加丰富的孔隙结构,强化煤焦-CO₂气化反应接触并抑制煤焦石墨化进程,从而提高煤焦气化反应活性;然而,热解温度过高或添加油泥量过多则会致使煤焦结构致密或孔隙堵塞,气化反应活性反而降低。     

污泥与煤共热解过程中磷元素的挥发规律研究

污泥灰分中磷元素含量明显高于煤,其中主要的晶体态含磷化合物为磷酸铁钙和少量的磷酸铝。利用高频加热反应装置考察了污泥-神府煤混合物快速热解过程中磷元素挥发规律。结果表明,污泥-神府煤混合物热解后磷元素主要存在于热解焦中。磷元素挥发比例随污泥添加比例的增加先升高后降低,随热解温度的升高而增加。热解温度不高于1 100 ℃时,混合物中以有机磷的挥发为主,磷元素挥发比例不高于3.2%。热解温度高于1 200 ℃后无机磷中磷元素挥发明显,1 300 ℃下最高有33.0%的磷元素随热解气体挥发出。     

纤维素与草酸的慢速和快速共热解反应特性研究

本研究利用热重-傅里叶变换红外光谱和卧式固定床热解反应装置,探究了纤维素与草酸的慢速和快速共热解反应特性。慢速共热解的失重曲线包括草酸分解和纤维素分解两个阶段,由于草酸与纤维素分解不同步,草酸主要通过其分解形成的挥发分影响纤维素的分解,且影响并不明显。而在快速共热解中,草酸与纤维素同步热解,原料及挥发分之间有着充分的交互反应,因此,草酸对纤维素的三相热解产物具有显著影响。相比于纤维素单独快速热解,快速共热解形成的生物油中左旋葡聚糖、左旋葡萄糖酮含量减少,1,4∶3,6-二脱水-α-D-吡喃葡萄糖含量显著提高;热解气中CO减少,CO₂增多;此外,纤维素分解更为彻底,热解炭具有更高的芳香化程度。     

煤—焦炉气共热解特性的研究：Ⅰ.固定床热解反应特性

在１０ｇ固定床反应器中对先锋褐煤在焦炉气气氛下的热解特性及有关工艺参数，如反应压力，升温速度等的影响进行了详细考察，并在其同等条件下的加氢热解特性进行了对比分析。实验结果表明，在反应压力５ＭＰａ，升温速率５Ｋ／ｍｉｎ，终态温度９２３Ｋ条件下，先锋褐煤在焦炉所氢气下的热解转化率为５９．０％，焦油收率达３８５．８％。     

平朔煤和生物质共热解实验研究

利用热重分析技术对平朔煤、生物质及两者混合物的热解特性进行了研究,考察了生物质掺混比例对平朔煤热解的影响。结果表明,不同掺混比例下生物质与平朔煤共热解时,平朔煤的挥发分析出温度和最大热解速率对应的温度呈现出规律性变化。将混合样品热解时的实际失重速率曲线与按比例折算后的曲线进行对比,发现实际失重速率曲线与折算曲线有所偏差,并不是平朔煤与生物质热解失重速率的简单加和,说明混合热解过程中有协同作用。同时,利用Coats-Redfern法,对平朔煤、生物质及两者混合物的热解主要阶段用一级反应过程描述,计算其动力学参数,发现反应活化能E和指前因子A随着生物质掺混比例不同呈现出规律性变化,对其规律进行了机理分析,证明了掺混生物质对平朔煤热解起到了促进作用,认为平朔煤与生物质共热解过程存在协同效应。     

水热炭化生物质与煤共热解和共气化特性研究

煤和生物质共热化学转化有助于当前化石能源系统的低碳化发展。本研究以烟煤和木质生物质为原料,研究煤和生物质共热解和共气化特性,并考察了不同水热炭化温度和生物质掺混比的影响。利用热重分析仪和在线质谱分析共热解和共气化的协同作用和氢气释放特性。采用Model-fitting方法,单独分析热解和气化阶段的整体反应动力学。结果表明,煤和生物质共气化阶段的协同作用显著强于共热解阶段。生物质比例越高,共气化协同作用越明显,水热炭化会削弱共气化的协同作用。共热解过程,H₂的产生受抑制。共气化过程可采用一级模型描述,而共热解过程需遵循n级反应模型。未处理的或轻度水热炭化的生物质与煤的混合物,共热解整体活化能和反应级数大于加权平均值,而其共气化的活化能变化趋势相反。重度水热炭化生物质与煤的混合物,共热解和共气化的活化能均接近加权平均值。     

含油污泥的热解特性研究

利用热重 傅里叶变换红外光谱联用仪与管式电阻炉对含油污泥热解特性进行了研究,分析了热解过程及影响因素（污泥性质与升温速率）,并由气体析出特性研究了热解机理。结果表明,热解过程包括水分挥发、轻质油挥发、重质油热解、半焦炭化与矿物质分解五种反应,矿物油反应集中发生在220℃～480℃。污泥性质影响因素中,产生环节最为显著,罐底泥、污水污泥失重明显而落地油泥失重不明显,矿物质组分含量越高,挥发分转化率越低;而污泥的油源基属影响较小。升温速率越大,反应进行的越快,挥发分转化率降低。热解机理包括矿物油含氧官能团裂解,链烃及侧链上的断链,环化、芳构化以及缩合脱氢。     

玉米秸秆与塑料PE共气化过程中碱金属迁移行为的研究

选取一定混合比例的玉米秸秆与塑料PE制成混合燃料,采用固定床实验台,通过改变反应温度,并结合化学热力学平衡分析、X射线衍射及扫描电子显微电镜能谱分析技术对共气化过程中碱金属的迁移行为进行研究。结果表明,气化气中碱金属以气态组元KCl、K₂Cl₂、NaCl形式存在。混合燃料中掺入塑料PE后,C、H含量增加,H使得共气化反应中更容易与Cl反应生成HCl,而非KCl,同时C更容易与K结合,导致K的释放率低于单独玉米秸秆气化,但使Na释放率增加。灰中碱金属化合物以KCl、NaCl、K₂SO₄、KAlSi₃O₈、KAlSiO₄、NaAlSi₃O₈、NaAlSiO₄为主,气化温度高于800℃后灰中K、Na、Cl更易沉积于微孔边缘。     

碱金属及相关无机元素在生物质热解中的转化析出

生物质热化学转化利用中遇到的颗粒聚团、受热面沉积等问题与生物质中的碱金属物质密切相关。本文首先对各种碱金属及相关无机元素在生物质中的存在形式和在热解中可能的行为进行了简要介绍 ,然后着重对稻杆热解中钾元素的析出过程进行了研究。通过计算得到了钾元素随热解过程析出的定量描述 ,计算出的半焦含钾量与试验实测值符合较好 ,说明采用的碱金属析出模型大体上反映了热解中相关元素转化、反应的主要过程。本文工作对于进一步研究碱金属及相关物质在燃烧、气化过程中的行为、探寻适合的解决途径有非常积极的意义。     

煤—焦炉气共热解特性研究：Ⅲ.热解焦油分析

采用色－质联用技术分析先锋褐煤在焦炉气气氛下热解油品的组成及其相对含量，主要考察了不同热解压力和升温速率对油品组成的影响并与相当氢分压下的加氢热解油品分析结果比较。结果表明，煤－焦炉气共热解焦油中含有非常丰富的苯、甲苯、二甲苯（ＢＴＸ），酚、甲酚、二甲酚（ＰＣＸ）以及萘。热解压力和升温速率对油品的组成及其相对含量有较大的影响。在实验条件下，压力升高和升温速率降低均有利于焦油中ＢＴＸ、ＰＣＸ和萘实际     

Speciation of Heavy Metals in Sewage Sludge and Sludge-Amended Soil

Abstract

The presence of heavy metals in sewage sludge restricts their agricultural use. Sequential extraction procedures may provide an assessment of the mobility of these elements in sludge and sludge-amended soil, and may help to predict the release of metals in soil solution. Nevertheless, the “phases” in which an element occurs are operationally defined and it is necessary to standardize a procedure in order to allow the comparison of result from different laboratories.     

污泥堆肥农用中重金属在海桐中的积累效应

采用小区试验的方法,研究了金华污水厂污泥堆肥土地利用过程中海桐根部对重金属的吸收及富集作用。结果表明,海桐对Cu均表现出比Zn更强的富集能力,而对Cd、Pb的富集能力很弱,其须根对重金属的吸收能力显著高于主根;就不同重金属的绝对吸收量而言,对Zn的吸收总量是最高的;须根中的Zn含量总体呈现随土壤中Zn含量增加而上升的趋势。     

A Comparison of Conventional and Ultrasound-Assisted BCR Sequential Extraction Methods for the Fractionation of Heavy Metals in Sewage Sludge of Different Characteristics

The purpose of this study was to determine the heavy metal (HM: Cd, Cr, Cu, Ni, Pb, Zn, and Hg) content in particular chemical fractions (forms) of sewage sludge with different characteristics (primary and dewatered sludge) using conventional (CSE) and ultrasound-assisted (USE) BCR sequential extraction methods (Community Bureau of Reference, now the Standards, Measurements and Testing Programme). The concentrations of HMs were determined using inductively coupled plasma optical spectrometry (ICP-OES). Only mercury was assayed with cold vapor atomic absorption spectrometry (CVAAS). Ultrasound treatment was conducted in the ultrasonic bath (Sonic 5, Polsonic). The optimal sonication time (30 min) was determined using ERM-CC144 (Joint Research Center; JCR) certified reference material. The conducted experiment revealed that the use of ultrasound waves shortened the extraction time to 4 h and 30 min (Stages I to III). The recoveries (R_M) of heavy metals ranged from 62.8% to 130.2% (CSE) and from 79.8% to 135.7% (USE) for primary sludge, and from 87.2% to 113.2% (CSE) and from 87.8% to 112.0% (USE) for dewatered sludge. The only exception was Hg in dewatered sludge. The conducted research revealed minor differences in the concentrations and fractionation patterns for Cd, Ni, and Zn extracted from sludge samples by the tested methods. However, it was confirmed that the above findings do not significantly affect the results of a potential ecological risk assessment (with minor exceptions for Cd and Zn in the primary sludge), which is extremely essential for the natural use of sludge, and especially dewatered sludge (the final sludge). The shorter extraction time and lower energy consumption prove that ultrasound-assisted extraction is a fast and simple method for HM fractionation, and that it provides an alternative to the conventional procedure. Therefore, it can be considered a “green method” for the assessment of the bioavailability and mobility of heavy metals in solid samples.     

Model Equations of State for Liquid Alkali Metals

Abstract

The structure of a model equation of state for the liquid alkali metals is proposed, in response to the observed failure of the principle of corresponding states, and limited tests are presented.     

离子色谱法同时分析中药中的碱金属与碱土金属离子

用离子色谱法简单快速地分析了中药中的阳离子。分析结果表明,川芎和酸枣仁中5种常见阳离子Na~+,NH~+_4,K~+,Mg~2+和Ca~2+的含量比例不同。各离子的检出限（S/N=3）为0.001～0.013mg／L,线性范围达3个数量级。     

Speciation Characteristics and Ecological Risk Assessment of Heavy Metals in Municipal Sludge of Huainan,China

In order to fully understand the morphological characteristics and pollution status of heavy metals in the dewatered sludge of Huainan Municipal sewage treatment plant, the physical and chemical properties were analyzed, and the content and occurrence forms of heavy metals (As, Cu, Zn, Pb, Cd, Cr, and Ni) in the sludge were studied using the geological accumulation method (Igeo), risk assessment coding method (RAC), and potential ecological risk index method to evaluate the ecological risk. The results showed that the municipal sludge in Huainan was rich in nutrients, with good prospects for agricultural utilization. There were differences in the morphological distributions of different heavy metals. The Igeo values for Ni, As, Cr, and Pb were below 0. The results of RAC indicated that the risk level of Cr in sludge was a low risk, and those of other heavy metals were moderate risks. The potential ecological risk of Cd had the highest potential ecological risk, and the other six metals were of low ecological risk. This conclusion can provide basic data and a theoretical reference for the comprehensive utilization of sludge in sewage treatment plants.     

1,2-Metallobridging and the Antiperiplanar Effect. Thermodynamic Preference for the Z-Configuration in Imidoyl(Alkali Metals) and their Phosphorus Analogs

We showed that imidoyl- and phosphaethenyl(alkali metals) would thermodynamically prefer the Z-configuration. The bond model analysis of the electronic structures showed that the Z-preference should originate from 1,2-metallobridging by the delocalization of lone pairs on N or P to vacant p-orbitals of the alkali metals and from the antiperiplanar effect of the delocalization from σ _C—M to σ? _{N(P)—R ²} and from n _N(P) to the C—R¹. The Z-preference increases by more electron-withdrawing groups at the carbon atom of the double bond. However, substitution at the nitrogen/phosphorus results in E-preference because of 1,4-chelation of the lone pair of the substituents to alkali metals. Most of halogen derivatives were not stable and eliminate metal halides.     

Estimation of Exchange Energies in Two-Component Melts of Alkali Metals

An approach allowing establishment of the relationship between the energies of mixing in binary homovalent melts of metals and the corresponding values for halide salts (chlorides or fluorides) of these metals is proposed. The procedure given as an example for estimation of the exchange energies in liquid-phase systems formed by lithium and other alkali metals allows a considerable reduction in the number of experimentally complicated definitions for thermodynamic characteristics of similar systems. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phosphine Production Potential of Various Wastewater and Sewage Sludge Sources

ABSTRACT

A laboratory incubation procedure followed by gas chromatographic detection was used to measure phosphine production potential in representative wastewater and sewage sludge sources. Phosphine production potential was determined by measuring the rate of phosphine formation in samples incubated under laboratory conditions over a seven day period when both electron donors and the targeted electron acceptor were not limiting factors. Results of our experiments showed that except the primary effluent and secondary effluent wastewater samples all other samples studied (influent wastewater, various type of sludge and sediment sources) produced phosphine. The minimum phosphine production potential value (0.39 pg/ml wastewater/day) was measured in composite influent wastewater samples while the maximum (268 pg/g wet sludge/day) was measured in sediment samples collected from an open-air sewage treatment plant.