Theoretical and experimental investigations into chemical kinetics models for supercritical CO2 oxidation

高压燃烧是清洁发电的一种可能途径。在高压（>7.3773 MPa）、富氧条件下燃烧会产生超临界二氧化碳（sCO2）和水蒸气的混合物。通过水蒸气的冷凝，sCO2的分离很容易，得到高纯度的sCO2，可以很容易地运输储存或重新利用。高压燃烧的另一个优点是需要一个较小的反应室来提供与在较低压力下进行燃烧的反应堆相同的能量输出。这将导致一个较小的燃烧装置，并降低资本成本。本项目旨在从理论上和实验上研究压力超过80 bar下sCO2生成的化学动力学机制。更好地了解sCO2生成的化学动力学模型将有助于更详细和准确的模型计算，从而帮助设计优化，用于高压发电厂的建设。此外，需要精确的化学机制来确保在超过80巴的压力下控制燃烧。该项目最初将包括查看过去的研究，以确定哪些机制已经被研究过，确定任何速率系数的准确性，以及它们是否可以用作模拟高压燃烧反应的起点。目前的燃烧方案是针对大气压下的系统开发的，使用的是在远低于sCO2临界点的压力下收集的实验数据。从这些实验中确定的实验速率系数不能准确地外推，也不能用于模拟压力超过80巴的燃烧，导致将当前模型应用于高温燃烧时的不准确性。由于这些模型可能忽略了在高压下变得重要的反应，或者只是在从实验数据推断到目前为止时给出了不正确的速率系数，因此产生了不准确性。在这个项目中，燃烧动力学将使用ANSYS Chemkin进行建模。灵敏度分析将在ANSYS Chemkin上应用，以识别在高压下燃烧机制中重要的反应。确定的反应将用激波管进行实验研究。该项目的一部分内容还包括协助建设激波管，该激波管将于2020年秋季开始建设。激波管将用于实验确定在高压下被认为是重要的反应的速率系数。然后将速率系数输入到ANSYS Chemkin模型中，以便在项目完成后生成准确的sCO2生产化学动力学模型。

High-pressure combustion is a possible route to clean power generation. Combustion under high pressure (>7.3773 MPa), oxygen-rich conditions would produce a mixture of supercritical carbon dioxide (sCO2) and water vapour. Separation of sCO2 would be facile via condensation of water vapour, giving high purity sCO2 which could easily be transported for storage or repurposing. A further advantage of high-pressure combustion is the requirement for a smaller reaction chamber to give the same energy output as a reactor undergoing combustion at a lower pressure. This would lead to a smaller combustion plant and reduce capital costs.This project aims to theoretically and experimentally study the chemical kinetic mechanism for the production of sCO2 at pressures exceeding 80 bar. A better understanding of the chemical kinetic model of sCO2 production would lead to more detailed and accurate model calculations to be used in the construction of high-pressure power plants by aiding in design optimization. Furthermore, an accurate chemical mechanism is required to ensure control over combustion at pressures exceeding 80 bar. The project will initially involve looking at past research to determine which mechanisms have been previously studied, the accuracy of any rate coefficients determined and if they can be used as a starting point for modelling the high-pressure combustion reaction.Current combustion schemes have been developed for systems at atmospheric pressure, using experimental data collected at pressures much lower than the critical point for sCO2. The experimental rate coefficients determined from these experiments cannot be accurately extrapolated and used to model combustion at pressures exceeding 80 bar, leading to inaccuracies when applying current models to high-temperature combustion. The inaccuracy arises as these models may have missed reactions which become important at high pressures or just give an incorrect rate coefficient when extrapolated so far from the experimental data.For this project, the combustion kinetics will be modelled using ANSYS Chemkin. Sensitivity analysis will be applied on ANSYS Chemkin to identify reactions which are important in the combustion mechanism at high pressures. The reactions identified will be studied experimentally using a shock tube. Part of this project also involves assisting in the construction of the shock tube which is set to begin construction in autumn 2020. The shock tube will be used to experimentally determine the rate coefficients of the reactions believed to be important at high pressures. The rate coefficients will then be input into the ANSYS Chemkin model to produce an accurate chemical kinetic model for sCO2 production upon completion of the project.