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。     

生物质与烟煤混合燃烧特性及动力学分析研究

使用非等温热分析方法研究了生物质(麦秆)和烟煤混合燃烧的反应特性。结果表明,生物质的添加可以降低混合样品的燃烧着火温度和燃烬温度,且混合样品燃烧反应性能随着生物质混合比例的增加而提升;生物质添加质量分数为20%时,煤和生物质混合燃烧协同作用最明显。使用Coats-Redfern(CR)、Flynn-Wall-Ozawa(FWO)和Kissinger-Akahira-Sunose(KAS)动力学模型对混合样品燃烧活化能进行计算,其值在挥发分燃烧阶段随着生物质混合比例的增加而增加,在焦炭燃烧阶段呈现下降趋势;通过对FWO和KAS动力学模型有效性进行分析发现,FWO和KAS模型在描述混合样品燃烧动力学时存在一定的局限性,而采用适宜机理函数的CR模型更适用于描述混合样品的燃烧反应动力学,对燃烧机理的分析也印证了动力学的分析结果。     

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。     

垃圾衍生燃料与褐煤共热解特性及动力学模型比较

以城市生活垃圾(municipal solid waste,MSW)的典型组成为样本基础,配制具有稳定物理化学性质的垃圾衍生燃料(refuse derived fuel,RDF).通过升温速率控制,探究不同升温速率对垃圾衍生燃料与褐煤共热解的影响;采用Coats-Redfern模型法以及Friedman,Flynn-WallOzawa(FWO)和Kissinger-Akahira-Sunose(KAS)无模型法,得到RDF与褐煤共热解反应动力学参数.结果表明:Coats-Redfern模型中,升温速率为10℃/min时,对应生物质组分及塑料类高分子聚合物热解阶段活化能最低;生物质组分及塑料类高分子聚合物热解阶段最优拟合级数分别为0.5和1.5;随着级数的增长,活化能与级数呈正相关关系.按照Friedman,FWO及KAS无模型法拟合的结果,转化率为α=0.1,α=0.2~0.6,α=0.7~0.9的共热解反应过程具有相似的动力学特性及反应机理.     

水稻秸秆与煤粉混合燃烧特性及动力学

采用热重分析法研究了水稻秸秆(RS)、煤粉(PC)及两者不同掺混比的混合物在不同升温速率下(10, 20, 40℃/min)从室温升至1000℃的燃烧特性，用Kissinger?Akahira?Sunose (KAS)法和Flynn?Wall?Ozawa (FWO)法计算了燃烧过程中的活化能。结果表明，失重速率(DTG)曲线中RS比PC多一个失重峰，且残余质量低。随升温速率增加，所有样品DTG曲线均向高温偏移，产生热滞后现象。RS和PC在混合燃烧过程中存在协同效应，且高温区域内更显著。PC掺混比例为50wt%时，混合物平均活化能的计算值较低，仅为76.0 kJ/mol (KAS)和83.2 kJ/mol (FWO)。     

城市污泥与稻壳水热炭混合燃烧特性与动力学

采用热重分析法研究城市污泥、稻壳水热炭及两者不同掺混比的燃烧特性与反应动力学。对比分析其在不同升温速率下从室温升至1000℃的燃烧特性，用Flynn-Wall-Ozawa (FWO)法计算其燃烧过程中的反应动力学参数。结果表明，稻壳水热炭的挥发性、着火和燃尽指数均高于城市污泥，具有较好的燃烧特性，掺混稻壳水热炭使城市污泥混合燃烧时发生热滞后现象。随着稻壳水热炭掺混比的增加，共混物的燃烧残余质量减少，着火性能变差，燃烧性能变强。活化能的相关系数均高于0.95，稻壳水热炭掺混高于50wt%时，共混物的平均活化能低于稻壳水热炭单独燃烧的平均活化能，掺混70wt%稻壳水热炭时出现最低平均活化能，为85.48 kJ/mol。城市污泥与稻壳水热炭混燃时有协同交互作用，且掺混50wt%稻壳水热炭时效果最佳。     

煤焦燃烧特性及反应活性探究

中国褐煤资源丰富,然而由于褐煤自身特点使其应用受到了极大的限制。针对中国褐煤应用最广的途径———燃烧,借助热重分析仪对不同热解终温的褐煤半焦及热解终温为1273 K的褐煤半焦与原煤的混合燃料的燃烧特性进行了分析。并利用Coats-Redfern法进行了燃烧动力学的分析,通过求得的表观活化能表征煤焦的燃烧反应活性。研究发现：热解终温越高,煤焦的燃烧特性越差;掺混褐煤有助于提高其半焦的燃烧特性,而掺混燃料的燃烧稳定性几乎和原煤无差别,且随着掺混比例的增加,混合燃料的活化能逐渐增大,越不易点燃,掺混半焦对燃料的燃烧特性和反应活性都有影响。相同制备条件下的烟煤半焦和褐煤半焦的燃烧动力学参数尤其是活化能相差很大,可见煤焦的燃烧反应活性与煤种有关。     

西藏卡玛多微晶菱镁矿热分解行为研究

为了给西藏卡玛多微晶菱镁矿的开发利用提供理论指导，以粒径≤0.5 mm的西藏卡玛多微晶菱镁矿为原料，采用热重（TG）曲线研究了不同升温速率条件下微晶菱镁矿的热分解特性，并进行了热力学计算，同时根据微晶菱镁矿的热重实验数据，采用非等温热重分析方法（FWO法和KAS法）计算了不同升温速率条件下微晶菱镁矿的热分解活化能，最后分析了微晶菱镁矿的分解产物氧化镁的微观形貌。分解热力学研究结果表明：随着升温速率的增大，微晶菱镁矿分解所需的热量逐渐增大，当升温速率从2℃/min逐渐增加到10℃/min时，分解所需的热量从187.93 kJ/mol逐渐增大到207.08 kJ/mol。分解动力学研究结果表明：采用FWO法和KAS法求得的热分解活化能与分解率的变化趋势相近，当分解率≤30%时热分解活化能随着分解率的升高而急剧下降，当分解率>30%时热分解活化能随着分解率的升高而下降缓慢，且逐渐趋于平缓。微晶菱镁矿分解后的微观形貌表明，升温速率越大，其分解产物氧化镁的晶粒越大。     

基于热重法的准东煤等转化率热解动力学模型

准东煤热解脱挥发分特性对其热加工利用过程具有重要影响,建立准东煤热解通用动力学模型对预测挥发分产率及反应性能具有重要意义。采用热重测量了不同升温速率条件下的准东煤脱挥发分失重特性,使用Friedman、Flynn-Wall-Ozawa（FWO）和Kissinger-Akahira-Sunose（KAS）3种等转化率模型来处理热重实验数据,仔细分析了不同模型参数的获得方法及不同模型中活化能及指前因子的差异。研究结果表明,准东煤活化能分布函数呈现单峰分布;相比其他模型,FWO模型能够较好地描述准东煤的热解过程。     

有机废弃物热解分析技术现状与展望

综述了有机废弃物热解过程中主要应用的分析方法，首先介绍热分析法的种类和影响因素，重点归纳了热重分析法的应用，明确了升温速率、热解气氛、驻留温度和驻留时间等是影响热解的重要因素；其次对热解动力学和热解热力学进行总结，对比了无模型法（FWO、KAS、Starink法）和有模型法（C-R法）；然后对热重-傅里叶红外联用分析（TG-FTIR）、热重-质谱联用分析（TG-MS）、热解-质谱色谱联用分析（Py-GC/MS） 3种热解气体逸出分析方法进行对比总结；最后从工业生产、研究热解机理和热解产物控制的角度提出目前有机废弃物热解分析技术的问题以及对未来热解技术发展的展望。     

Thermogravimetric study for the co-combustion of coal and dried sewage sludge

The co-combustion of dried sewage sludge with coal is a promising method to dispose of and treat sewage sludge waste. Because sewage sludge has a different elemental composition than coal, the co-combustion of sewage sludge with coal may have different combustion characteristics than the single combustion of coal. In this study, the co-combustion of dried sewage sludge with coal was tested varying heating rates and mixing ratios of the dried sewage sludge. The results were analyzed using thermogravimetric (TG) and derivative thermogravimetric (DTG) curves and modeled using Ozawa-Flynn-Wall and Vyazovkin models. The mixed samples of coal and dried sewage sludge showed similar TG curves to the coal sample. The co-combustion showed activation energies close to that of the single coal combustion. This suggests that the co-combustion of coal and dried sewage sludge has similar combustion behavior to the single combustion of coal for mixing percentages of dried sewage sludge up to 20%.     

Co-Combustion of Oil Sludge Char and Brown Coal in a Continuous Fluidized-Bed Combustor

For developing technologies for innocent disposal of/energy recovery from high-ash oil sludge char (OSC), it was continuously combusted in a 10 kg h⁻¹ fluidized-bed combustor. Addition of brown coal (BC) improved its combustion, but excessive BC was prone to cause slagging. Fine coke particles in OSC and volatiles in BC led to staged temperatures along the fluidized bed through air-staging co-combustion, enabling excellent combustion performance as well as efficient NO_x reduction, especially when coupled with selective non-catalytic reduction. Thus, there is a potential to cleanly recover energy from OSC by its co-combustion with BC.     

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。     

Study of the kinetic behaviour of biomass and coal during oxyfuel co-combustion

In this study, the thermogravimetric analysis(TGA) method has been used to evaluate the kinetic behavior of biomass, coal and its blends during oxyfuel co-combustion. The thermogravimetric results have been evaluated by the Coats–Redfern method and validated by Criado's method. TG and DTG curves indicate that as the oxygen concentration increases the ignition and burn out temperatures approach a lower temperature region. The combustion characteristic index shows that biomass to coal blends of 28% and 40% respectively can achieve enhanced combustion up to 60% oxygen enrichment. In the devolatilization region, the activation energies for coal and blends reduce while in the char oxidation region, they increase with rise in oxygen concentration. Biomass, however, indicates slightly different combustion characteristic of being degraded in a single step and its activation energies increase with rise in oxygen concentration. It is demonstrated in this work that oxygen enrichment has more positive combustion effect on coal than biomass. At 20% oxygen enrichment, 28% and 40% blends indicate activation energy of 132.8 and 125.5 kJ·mol~(-1) respectively which are lower than coal at 148.1 kJ·mol~(-1) but higher than biomass at 81.5 kJ·mol~(-1) demonstrating synergistic effect of fuel blending. Also, at char combustion step, an increase in activation energy for 28% blend is found to be 0.36 kJ·mol~(-1) per rise in oxygen concentration which is higher than in 40% blend at 0.28 kJ·mol~(-1).     

Transformation of mineral and emission of particulate matters during co-combustion of coal with sewage sludge

Co-combustion of coal with sewage sludge was carried out in laboratory-scaled drop tube furnace to understand the interaction between different fuels. The combustion conditions were selected as follows: the raw material feeding rate was 0.2-0.3 g/min, temperature was 1200 °C, the atmosphere of 10% O₂ and N₂ being balance was used to guarantee an air ratio of 1.5, and the residence time varied from 0.6 to 2.4 s. The coal/sewage sludge is kept at 50:50 (wt% to wt%), four fuel pairs were selected with respect to the mineral association within individual fuel. The results showed the obvious interaction between coal and sewage sludge during their co-combustion. For the carbon conversion, the devolatilization of mixing fuel occurred quickly; the combustion of both char and evolved volatile progressed almost completely. As a result, the unburnt carbon was almost zero in the fly ash. In addition, the evolution of both mineral and PM varied with the association of minerals in raw fuels. For both coal and sewage sludge rich in included minerals, they combusted separately in the furnace, less interaction occurred accordingly. Conversely, for both them rich in excluded minerals, the minerals reacted with each other to form much agglomeration, and therefore, the particle size of the fly ash was increased, while the amount of PM was decreased, which changed as the coarse fly ash particles. Finally, for the case of coal rich in excluded mineral and sludge rich in included mineral, their co-combustion led to the interaction of their minerals. As a result, more the fine particles were formed, which in part changed into PM. For the vaporized trace elements, they were adsorbed by the melt CaPO₄/Al-Si in the ash and accordingly, their contents in the particulate matter were reduced whereas their particle size distribution shifted to the large value.     

热重-红外联用分析制革污泥的燃烧特性

利用TG-FTIR对制革污泥的燃烧特性和燃烧过程气体释放情况进行了研究。研究发现,制革污泥挥发分和灰分含量较高,固定碳含量低、热值低。不同升温速率下,制革污泥的燃烧在800℃时已经比较充分,随着升温速率的增加,制革污泥碳燃烧的失重速率和峰值温度有所增加。运用Ozawa法进行活化能计算表明,制革污泥燃烧所需活化能随着反应程度的深入而增加。制革污泥的挥发分燃烧阶段符合三维扩散的Z-L-T方程反应模型,固定碳燃烧阶段符合自催化反应的P-T方程反应模型,且制革污泥在不同升温速率下燃烧动力学参数存在动力学补偿效应。TG-FTIR分析表明,不同升温速率对气体析出基本特征没有影响,在低温阶段,制革污泥的燃烧产物中有少量的有机酸组分析出。     

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,随着烘焙温度上升,其质量产率和能量产率逐渐降低,挥发分析出与燃烧区间逐渐减小,固定碳燃烧区间逐渐增大;MSW-260与BC掺混能有效改善烟煤的燃烧特性,提高混合样的燃烧速率;升温速率上升会产生热滞后现象,MSW-260与BC混合燃烧各反应阶段向高温侧移动,且升温速率越快偏移越明显。综合动力学分析以及燃烧特性参数分析来看,在保证资源高利用率和良好的燃烧状况条件下,MSW-260与BC混燃质量比可以选用5∶5。