HotSpot: High temperature behaviour of potentially toxic and corrosive trace elements in thermal gasification systems

碳燃料的热化学转化导致大量微量元素的排放，例如重金属、砷等有毒物质。在工厂中，微量元素会导致热交换器和涡轮机的腐蚀、催化剂中毒、膜的失活，并且通常工厂下游部分的效率会降低，例如二氧化碳的封存、甲烷和液体燃料、基本化学品和肥料的生产。先进、高效的发电厂工艺，例如可以使用生物质、衍生燃料和煤的综合气化联合循环，需要适当的气体净化。在过去的几十年里，科学研究导致电厂产生的几种空气污染物显著减少，例如硫氧化物、氮氧化物。然而，微量元素的转化行为尚未得到详尽的研究，特别是在气化条件下。计划研究的目的是确定微量元素As， Pb, Sn， V的释放机制，它们的气相化学和冷凝行为，这是有效的热气体净化的基础。具体的热力学数据将作为气化炉的重要工艺参数（温度，蒸汽含量）和重要的微量气体（H2S和HCl）的函数来确定。数据将被实现到一个模型中。第一个重要的方法重点是量化气化条件下所研究的参数的影响。这对建模很重要，因为它强调了影响因素的价值。由于过去主要研究的是燃烧现象，因此所得结果将大大拓宽建模的数据库。第二个重点是用分子束质谱法直接测定热气体中的气相物质。在这个主题背景下，将首次在全球范围内进行重要气相物种的在线测定。它允许通过检测重要的气相物种来证明理论转化机制，并修改机制（如有必要）和/或提出新的机制。最后，本研究旨在建立选定数量的微量元素释放和凝结的热力学模型。该模型应能够描述和解释转化行为的基本特征，并预测修改工艺参数后的行为。进一步的研究可以a)包括更多的重要微量元素，例如水银，镉，和/或b)关注相关应用的工艺参数，例如水泥工业或危险废物处理。

The thermochemical conversion of carbonic fuels causes the emission of significant amount of trace elements, e.g. heavy metals, arsenic, which can be toxic. In the plant the trace elements can cause corrosion of heat exchangers and turbines, poisoning of catalysts, inactivation of membranes, and in general the efficiency of downstream parts of the plant can decrease, e.g. sequestration of CO2, production of methane and liquid fuels, basic chemicals and fertilisers. Advanced, highly efficient power plant processes, e.g. the integrated gasification combined cycle which can use biomass, derived fuels and coal, need a proper gas cleaning. During the last decades scientific research lead to significant reduction of several air pollutants from the power plants, e.g. SOx, NOx. However, the transformation behaviour of trace elements has not been exhaustively investigated, especially for gasification conditions.The planned study aims the determination of release mechanisms of trace elements As, Pb, Sn, and V, their gas phase chemistry and their condensation behaviour which is the fundament for effective hot gas cleaning. Specific thermodynamic data will be determined as a function of important process parameters of gasifiers (temperature, steam content) and significant trace gases (H2S and HCl). The data will be implemented into a model. The first important methodical focus is the quantification of the influence of the parameters under investigation at gasification conditions. This is important for the modelling, because it put emphasis on the value of the influencing factor. The obtained results will broaden the data base of modelling significantly, because mainly combustion phenomena have been investigated in the past.The second important focus is the determination of gas phase species directly in the hot gas using Molecular Beam Mass Spectrometry. The online determination of significant gas phase species will be done for the first time worldwide in this thematic context. It allows to proof theoretical transformation mechanisms by detection of important gas phase species and to modify mechanisms (if necessary) and/or to propose new mechanisms.Finally, the study aims to build up a thermodynamic model of release and condensation of a selected number of trace elements. The model shall be able to describe and explain the transformation behaviour in its essential characteristics and to predict the behaviour for modified process parameters.Further studies can a) include a broader number of significant trace elements, e.g. quicksilver, cadmium, and/or b) focus on process parameters of relevant applications, e.g. for the cement industry or hazardous waste treatment.