煤热解动力学模型的建立

通过对煤热解反应动力学分析,基于分布活化能模型DAEM,建立了集总反应动力学模型表示煤炭热解过程。确定了可以预测热解产物组成、分布与热解终温和升温速率关系的动力学方程。结果表明：随热解温度升高,各种挥发分产物析出率越来越接近最大产率;半焦C含量增加,但产率下降,H,O,N和S等元素降低。升温有利于提高半焦脱硫率、脱氮率。温度为600℃左右时,除H2外的大部分挥发分基本析出,半焦元素变化幅度减小。热解终温较低且一定时,较慢的升温速率有利于各热解挥发分最大限度析出。秦丽娜     

桦甸页岩油泥与半焦混烧特性

利用热重分析仪对桦甸页岩油泥与其500℃半焦混合燃烧时着火温度和燃烧特性进行考察,通过FTIR研究样品的混烧特性及气体释放规律,分析混合比和升温速率对混烧特性的影响并通过FWO法对样品混烧的动力学特性进行了研究。结果表明,样品的燃烧分为3个阶段:油泥轻质组分燃烧阶段、油泥重质组分与半焦挥发分共燃阶段及固定碳燃烧阶段。油泥比例的增大及升温速率的提高导致综合燃烧特性指数和稳燃指数逐渐增大,说明油泥和升温速率有利于混合样品的燃烧特性。油泥比例的增大促进气体释放速率逐渐加大,A(CO_2)/A(CO)呈现出先减小后增大然后再增大的趋势,与油泥比例不成线性关系,说明油泥掺入有利于样品的燃烧,但并不一定有利于样品的燃尽。除样品S1外,其他样品活化能变化规律相似。轻质油燃烧阶段活化能在50—100 k J/mol,共燃阶段活化能在100—150 k J/mol,固定碳燃烧阶段活化能达到了300 k J/mol左右。     

利用TG-FTIR系统研究氧气浓度对污泥干化焚烧的影响

利用TG-FTIR系统,分析了污泥在升温过程中的质量变化,以及氧气浓度对失重过程和气体释放的影响.研究结果表明:污泥的失重过程可分为四个阶段,即水分蒸发-有机质挥发和分解-有机质分解和燃烧-碳燃烧;氧气浓度越大,有机质挥发和分解速率越大;本次实验中氧气浓度为17.65％的气氛下,污泥中有机质能够完全分解或燃烧,释放的气体量最大;在氧气浓度为6.67％和12.65％的气氛下,污泥中的部分有机物并不能完全分解和燃烧.     

麦渣与制浆废液共混制备成型颗粒燃料及其燃烧特性分析

为研究麦渣与制浆废液共混制备的成型颗粒燃料的燃烧特性,通过热重分析法对其燃烧热力学及燃烧动力学进行了研究。结果表明：制浆废液的添加使颗粒燃料出现固定碳的二次燃烧阶段,有利于降低成型颗粒燃料的挥发分、固定碳燃烧阶段的点火温度及最大燃烧速率温度,对颗粒燃料的燃烧有正向协同作用;制备的颗粒燃料的一阶动力学模型拟合曲线的相关系数在0.95以上,颗粒燃料在挥发分燃烧和固定碳燃烧阶段的活化能和指前因子均随制浆废液的添加而降低。当废液固形物质量分数为53%时制备的成型颗粒燃料,其挥发分燃烧阶段和固定碳燃烧阶段的活化能为72.85和83.52 kJ/mol,指前因子为2.82×10⁶和3.73×10⁵ min^-1。制浆废液的添加使颗粒燃料更易燃烧,且燃烧过程稳定不易爆燃。     

醇提中药渣与废弃活性焦共燃特性及动力学分析

采用热重分析法研究了不同升温速率下醇提中药渣、废弃活性焦及其不同比例混合物的燃烧特性,并利用Coats-Redfern方法计算其燃烧动力学参数。结果表明,醇提中药渣燃烧是挥发分和少量固定碳连续燃烧过程,而废弃活性焦燃烧主要是固定碳燃烧的过程;醇提中药渣比废弃活性焦具有更好的燃烧特性和更低的活化能。采用TG-MS联用分析仪对比研究醇提中药渣及其混合物的燃烧过程产生的烟气。结果表明,废弃活性焦的加入对醇提中药渣燃烧过程中产生的NO_x有明显的吸附还原作用。动力学分析表明,与废焦相比,混合物反应活化能随着中药渣比例的增加而变小,表明添加中药渣能提高废焦的反应活性,促进其燃烧。利用热重分析预测混合燃料的燃烧性质可靠,对醇提中药渣与废弃活性焦共燃处理的技术开发具有指导作用。     

桦甸油页岩热解过程中气体析出特性

通过热重-红外-质谱(TG-FTIR-MS)三机联用技术对桦甸油页岩在不同升温速率的条件下进行热解实验,计算了其挥发分气体析出阶段的动力学参数,并对整个热解过程中挥发分气体的析出特性进行了分析,获得了挥发分气体析出的红外三维谱图及CH_4、CO_2、CO、H_2O、CnHm和H_2共6种气体的析出速率随温度变化的规律曲线。其中甲烷作为热解析出的主要气态烃类产物,是多种反应综合作用的结果,故采用分峰拟合的方法对其在升温速率为20℃/min下的析出过程进行分析。结果表明,在300~600℃这一温度区间,甲烷的生成速率曲线可以分为4个峰,代表了4个反应类型,分别计算了其动力学参数,结合桦甸油页岩的结构特性及热解过程中其他气体析出的特性,分析了各个反应甲烷的生成机理。     

印尼油砂热重红外及基于AKTS动力学分析

通过热重分析仪、傅里叶红外光谱仪和质谱仪对印尼油砂的热解过程和热解产物进行了探究,基于不同升温速率下的TG-DTG曲线,将热解过程分为两个阶段,即热解低碳化合物析出段和无机物高温受热分解段。升温速率相同时,YN₂油砂比YN1油砂挥发分析出的温度低。油砂热解产物是由脂肪烃、芳香烃、含氧官能团和羟基等组成的混合物,利用傅里叶红外光谱仪探究印尼油砂在不同升温速率下气体产物H₂O、CO₂、CO、CH₄、C_nH_m等的析出特性,气态烃类、含氧有机物等有机气体是由羰基和羧基以及甲氧基、亚甲基、甲基在热解低温段受热分解产生的,根据质谱图,确定了各个时刻逸出气体的种类和产量。利用AKTS软件基于F-W-O和Kissinger模型计算了油砂脱挥发分的热解动力学参数,计算结果表明,在相同的转化率下,不同升温速率的活化能呈线性分布,YN1的活化能高于YN₂的活化能。     

安徽临涣矿区烟煤与生活污泥共燃的燃烧特性与动力学特征

以安徽淮北临涣工业园燃煤电厂煤样品和生活污水处理厂污泥样品为研究对象,采用热重分析法(TGA)对不同混合质量比条件下的煤与污泥进行了共燃实验,同时通过五种反应动力学模型研究了不同燃烧阶段煤、污泥样品共燃的动力学特征,揭示了煤和污泥的燃烧特性。研究结果表明,煤在529℃出现一个失重峰,污泥分别在140, 293和430℃出现三个失重峰,表明污泥的燃烧过程分为三个失重阶段,而煤只有一个失重阶段。煤的可燃性指数与综合燃烧特性指数为11.36×10–6 mg/(K–2•min), 47.16×10–10 K–3•min–2,与煤相比,污泥的可燃性指数与综合燃烧特性指数较低,分别为10.74×10–6 mg/(K–2•min), 13.04×10–10 K–3•min–2。在煤中添加污泥可以提高反应的燃烧特性,混合质量比以90(煤):10(污泥)为宜。随升温速率升高,煤与污泥的失重减少,燃烧失重速率增加,DTG曲线向高温区移动,产生热滞后现象。在固定碳燃尽阶段,混合燃料的活化能均位于两种原料之间,并且随污泥添加量增加而降低,表明污泥的添加有效提高了煤的反应活性并促进其燃烧过程。     

生物质理化特性与热解动力学参数相关性研究

以10、20和30℃/min的升温速率对油茶壳、玉米秸秆、汉麻秸秆和稻壳展开热解特性分析,采用CR法、FWO法和KAS法研究其热解动力学过程,并利用Pearson相关系数研究其理化组成与不同升温速率下的热解特性和热动力学参数之间的关系。结果表明,CR法计算的四种生物质平均活化能远低于FWO法和KAS法;Pearson相关性结果表明,C含量显著影响挥发分含量,O含量显著影响样品残重率,固定碳含量显著影响FWO法和KAS法计算的热解平均活化能,灰分与挥发分含量均显著影响生物炭的产率和低位热值。     

吐哈盆地褐煤的热解和燃烧特性及动力学分析

吐哈盆地褐煤的热解和燃烧特性研究利于煤的清洁高效利用及煤炭地下气化的开展,为探究吐哈盆地褐煤煤粉颗粒的热解特性和燃烧特性及动力学特性,通过热重实验、热解特征指数计算、综合燃烧指数计算及动力学软件Kinetics Neo模型拟合法,研究了煤粉在不同升温速率(5℃/min, 10℃/min, 20℃/min)和不同粒径(大于0.8 mm, 0.2 mm～0.6 mm,小于0.1 mm)下分别在氮气气氛中的热解特性和空气气氛中的燃烧特性,获得了不同条件下煤粉颗粒热解和燃烧过程的动力学参数。结果表明：升温速率升高有利于煤粉颗粒热解和燃烧,显著提升了热解和燃烧性能;煤粉颗粒粒径增大有利于煤粉热解,不利于煤粉燃烧;不同粒径煤样热解和燃烧焦产率没有明显区别,粒径增加对于挥发分释放的影响不大;热解与燃烧过程中活化能与指前因子分别在一次热解阶段和干燥挥发阶段较高,说明在这两个阶段反应速率较慢,单位时间内化学反应程度较高。     

油泥焦与褐煤共燃特性及动力学

采用热重分析法研究了不同升温速率下油泥焦、褐煤及其混合物燃烧特性,并利用Kissinger-Akahira-Sunose（KAS）、Flynn-Wall-Ozawa（FWO）和Friedma（FR）等方法计算其燃烧动力学参数。结果表明,油泥焦燃烧主要是固定碳燃烧过程,而褐煤燃烧是挥发分和少量固定碳连续燃烧的过程。褐煤比油泥焦具有更好的燃烧特性,平均活化能更低。油泥焦和褐煤共燃过程中存在明显的协同促进作用,当混合燃料中褐煤占比为75%时协同促进效应达到最强。通过比较KAS、FWO和FR的结果发现,FR法能够更好地体现反应变化的趋势,而KAS法和FWO法的结果具有较高的准确性。通过比较油泥焦和褐煤共燃动力学参数的理论计算值与实验计算值发现,利用热重分析预测混合燃料的燃烧性质具有较高的可靠性,对油泥焦与褐煤共燃技术的应用具有重要的指导作用。     

Kinetics of pyrolysis and combustion of oil shale sample from thermogravimetric data

Thermogravimetric (TG) data of oil shale obtained at MI (Waste to Energy laboratory) were studied to evaluate the kinetic parameters for El-Lujjun oil shale samples. Different heating rates were employed simulating pyrolysis reaction using Nitrogen as purging gas up to ∼800 °C. The extent of char combustion was found out by relating TG data for pyrolysis and combustion with the ultimate analysis. Due to distinct behavior of oil shale during pyrolysis, TG curves were divided into three separate events: moisture release; devolatization; and evolution of fixed carbon/char, where for each event, kinetic parameters, based on Arrhenius theory, were calculated. Three methods were used and compared: integral method; direct Arrhenius plot method; and temperature integral approximation method. Results showed that integral method is closer to the experiment, while no relationship was observed between activation energy and the heating rate.     

Research on combustion characteristics of bio-oil from sewage sludge

Combustion characteristics of bio-oil from sewage sludge were investigated using thermogravimetry (TG) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques. The combustion process could be divided into two weight loss stages. Light compounds volatilized and were oxidized in the first stage and the heterogeneous combustion between oxygen and heavy compounds happened in the second stage, which were confirmed by FT-IR technique. Most weight loss occurred in the first stage. The effect of heating rate was also studied and higher heating rates were found to facilitate the combustion process. The kinetic parameters of the two stages were calculated and the change of activation energy indicated higher heating rates benefited combustion.     

Investigation on the combustion possibility of dry sewage sludge as a pulverized fuel of thermal power plant

Combustion possibility of three dry sludges as pulverized fuel of coal power plant like sub-bituminous Minco coal was studied by thermogravimetric analysis (TGA) and Drop Tube Furnace (DTF). TGA results showed that the fixed carbon contained with minor content in dry sludge was slowly burned than it of Minco coal. The linear regression for the Arrhenius plot to the experimental data is very good, and activation energies for overall combustion of Minco coal and DDSS are 64.382 and 26.799 kJ/mol, respectively. But, combustion patterns of KDSS and SDSS divided into devolatilization and oxidation reaction. It was derived that activation energies for the devolatilization of KDSS and SDSS are 27.127 and 12.571 kJ/mol in reciprocal proportion to volatile matter content, the fixed carbon combustion derives to 45.289 kJ/mol for KDSS, 33.777 kJ/mol for SDSS. Test results show that the volatile content in sludge significantly improved the combustion reactivity whereas the time for the combustion completion delayed. The conversion behavior of the coals and sludge observed in DTF was similar to that reflected in TGA. DTF studies showed that the individual sludge was lower conversion than the Minco coal, but the combustion of most sludge was completed at residence time of around 1 s, set temperature range of 1200 °C similar to commercial coal fired plant. These high IDT of sludge ashes with minimum 1214 °C are not expected to be associated with slagging and fouling in pulverized coal fired systems.     

Evaluation of pyrolysis residue of oil sludge for recycling as bed material

Pyrolysis is an appealing technique to convert oil sludge into valuable products such as gaseous and liquid fuels, however, there is lack of research on the use of solid residue after sludge pyrolysis. This work investigated the possibility of recycling solid residue as bed material for the pyrolysis process. The thermogravimetric analysis of the raw sludge in both the pyrolysis condition and combustion condition found that part of the heavy organic compounds in the oil sludge was difficult to recover by pyrolysis, though could be combusted easily in the presence of oxygen. Therefore, by leaving the heavy compound in the solid residue, the solid residue can be self-heated by combustion and cycled to the pyrolysis process to enhance heat transfer and catalysis. A series of pyrolysis residues at varies temperatures and holding times were collected after pyrolyzing oil sludge in this study. To examine whether there is sufficient potential heat remaining in the pyrolytic residue, the residue was further investigated by FTIR, proximate, ultimate analysis, and TGA in air to study the combustion characteristics and combustion kinetics. Higher pyrolysis temperature and longer pyrolysis time resulted in more ash and fixed carbon in the residue, though less volatile matter. Residue pyrolyzed at a lower temperature was easier to combust and showed lower combustion activation energy, though the recovery of organic fuel was not significant. Pyrolysis time had very minor effect on the solid residue combustion behaviour. It is more appropriate to control the residue property by governing the pyrolysis temperature.     

低温烘焙下城市生活垃圾与烟煤的混燃特性

为了探讨垃圾与煤的混燃特性,选取城市生活垃圾(MSW)和烟煤(BC)为研究对象,通过热重分析法研究烘焙温度、掺混比例、升温速率对样品燃烧特性的影响,并采用Kissinger-Akahira-Sunose(KAS)法计算样品的活化能.结果表明:MSW经220℃,260℃和300℃低温烘焙后,热值都有所提升,随着烘焙温度上...     

Kinetics and Combustion Characteristics of Deinking Sludge in a Thermobalance and an Internally Circulating Fluidized Bed

The kinetic parameters (activation energy, pre‐exponential factor and reaction order) of volatile and char of deinking sludge are determined by thermo‐gravimetric analysis. From the Arrhenius plot, the activation energy and the pre‐exponential factor of char are determined. The reaction order is found to be 0.7 with respect to oxygen partial pressures of 507 – 3040 Pa. The effects of riser gas velocity, solid feeding rate and annulus air on combustion efficiency have been determined in an internally circulating fluidized bed (ICFB). The combustion efficiency decreases with increasing riser gas velocity and solid feeding rate, while it increases with increasing annulus air. High combustion efficiency is obtained when the annulus air is injected.     

预处理稻壳及其与杨树锯末掺混燃烧特性和燃烧动力学分析

采用热重技术对稻壳（DK）和杨树锯末（JM）燃烧进行分析,考察了不同预处理方式对稻壳燃烧特性的影响,并研究了不同升温速率及稻壳和杨树锯末掺混质量比对掺混燃烧特性及燃烧动力学的影响。结果表明：水洗及酸洗可使稻壳燃烧TG-DTG热重曲线向高温区移动,最大失重速率及对应失重温度升高。水洗使稻壳综合燃烧特性指数提高2.5×10^-7~5.9×10^-7%/（min²·℃³）,而酸洗使稻壳综合燃烧特性指数下降11×10^-7~11.9×10^-7%/（min²·℃³）。不同预处理后稻壳在挥发分析出燃烧阶段的活化能高于未处理稻壳,酸洗后稻壳焦炭燃烧阶段活化能降低16.94 kJ/mol,而水洗使稻壳焦炭燃烧阶段活化能升高。提高稻壳添加比例,混合燃料着火温度和燃尽温度降低。随着升温速率的提高,混合样品综合燃烧特性指数和残余率升高。70%稻壳和30%杨树锯末混合燃料在升温速率40℃/min下燃烧产生协同效应。     

三种木材的裂解动力学研究

在氮气氛和不同的加热速率下对三种木材(马尾松、棉杆和杉木)进行了热重分析.同时研究了碳酸钠对这三种木材热解的催化效应.运用Popescu法从22种动力学机理函数中寻求裂解的最概然机理函数并计算裂解的动力学参数.结果表明,Zhuralev,Lesokin and Tempelmen(Z-L-T)方程为最概然机理函数.根据Z-L-T方程计算的动力学参数表明,在裂解的低转化率范围,碳酸钠可以降低表观裂解活化能,而在裂解的高转化率范围,碳酸钠可以增加表观裂解活化能.根据木材的结构成分对碳酸钠的催化行为进行了分析.