富盐有机废液焚烧灰组分形成过程与演变机理研究

During incineration process incombustible inorganic salts containing in organic wastewater with complex composition, high toxicity and poor biodegradability are released and transformed to ash forming species which have high adhesion properties, and furthermore cause some severe ash–related problems, such as troublesome fouling, slagging, and even corrosion. In this research, experimental study and theoretical analysis will be performed to explore formation process and evolution mechanism of ash forming species generated by incineration of typical concentrated organic wastewater rich in salts. Continuous capture and measurement of alkali vapors and solid/molten/semi–molten ash particles which are involved in ash forming species are realized by building a visual and measurable quantitatively experiment system combined with MBMS technology. Moreover, this proposal focuses on the influence of the key factors such as environmental parameters, capture surface structure, alkali vapor concentration, physical and chemical parameters of ash forming species and evolution characteristic parameters on formation process and evolution mechanism of ash forming species. On the basis of striving to define scientifically the interaction mechanism of these key factors, the influences of this interaction mechanism formation process, evolution and development tendency of ash forming species are further expounded, and then summarize the differentiated evolution mechanism and development tendency of alkali vapors and ash particles during formation and development process. It is expected to explore and develop the important basic science issue of formation process, evolution mechanism as well as development tendency of such ash forming species rich in alkali salts and gain deeper insights into the primary cause for appearance of fouling and slagging.

成分复杂、可生化性差的有机废液含有的不可燃无机盐在焚烧过程中释放并转化为具有高粘附特性的灰组分，导致严重积灰结渣甚至产生腐蚀现象。本项目通过实验研究和理论分析相结合的手段，以典型富盐有机废液焚烧灰组分的形成过程、演变机理及发展规律为关键问题进行研究，通过联合MBMS技术构建可视化、可测量化的实验系统对灰组分中气态碱蒸气和固/熔融/半熔融态飞灰粒子进行捕获，对灰组分沉积物动态发展趋势进行观测，重点研究环境参数、捕获表面结构、碱蒸气浓度、灰组分理化特征等关键因素对灰组分形成过程和演变机理的作用规律，在分析关键因素相互作用机制的基础上，进一步阐述这种相互作用机制对灰组分形成过程、演变机理和发展趋势的影响规律，总结碱蒸气和飞灰粒子在形成和发展过程中的差异化演变机制和发展趋势。最终从本质上揭示富碱盐型灰组分形成过程、演变机理和发展规律等基础科学问题以及积灰结渣和腐蚀现象出现的根本原因。

对于生产生活排放的有机废水（液），由于其成分复杂、可生化性差，通常采用热化学转化的方法进行处置，然而有机废液中富含的不可燃无机盐类，特别是碱金属盐类由于具有高粘附特性，极易导致积灰结渣甚至产生腐蚀现象。针对富碱盐型灰形成组分理化特性、熔融过程的演变和发展规律以及动力学模型的构建，主要开展了如下工作：.首先，选取典型的高含盐的不同来源有机废液，采用工业规模焚烧装置和实验室进行燃烧实验，获得不同热力环境下的富碱盐型灰形成组分。较高的Na含量造成高温段灰渣样品的灰熔融温度偏低；从中温段到低温段，灰渣样品中Fe和Ni含量逐渐降低，而S表现为低温富集的特征，灰熔融初始变形温度和流动温度间隔仅有51–129 K，整体上呈先上升后降低的趋势。低熔点共晶体Na3Fe(SO4)3和Na2Ni(SO4)2和晶体结构不稳定的Na3H(SO4)2造成主熔融过程较高温段样品提前200–300 K，并伴随显著的失重。动力学求解表明，低熔点共晶体不仅在温度较低时即可发生吸热熔融，而且所需活化能比Na2SO4晶体熔融活化能低得多。.而在不同灰化条件下，灰分反映出污泥在焚烧过程中差异性的反应进程，随受热温度升高，都出现了矿物质失去吸附水，矿物质析出结晶水，污泥中有机物燃烧，方解石分解，以及随后的硬石膏分解等阶段。灰分各失重阶段反应级数大部分都不为理想值，说明实际反应进程与理想进程有一定的偏差。氧化气氛会促进反应进程使各失重峰提前，同时也会促进污泥中有机物质转化。一般来讲较低温灰分保留了污泥较多原有特征，吸热量大于高温度灰分。发现了污泥中Na、S、P等对灰熔融过程以及对动力学模型和参数的影响机制。.在富碱盐型废液资源化利用途径，利用TG/DSC–FTIR技术研究典型污泥的共热解/燃烧特性、反应热效应、固相产物表面化学官能团演变规律和气相产物释放特性，并建立了多步独立的连续反应动力学模型，获得了主要化学官能团的红外吸收峰宽度和强度受热解温度、掺混比例的影响机制；同时随污泥掺混比例增加，燃烧残留物的烧结、熔融现象逐渐增强。