Novel and efficient microwave plasma furnace for processing and syngas production

兰开斯特化学工程博士项目发现，随着大气压微波(MW)等离子体处理技术的规模扩大，组件的效率和寿命得到了提高，该项目使用微波等离子体炬气化有机废物。受STFC资助的研究(主要是Cockcroft研究所资助的STG008248/1和ST/P002056/1)的启发，兰开斯特射频加速器工程师提出了一种解决方案，允许等离子体在大直径无衬镍钢管中撞击，大大减少了壁面损失，并且没有等离子体追溯到发生器的趋势。随后的一个本科生项目证明了这一原则。已经提出了专利申请。创新之处在于使用模式转换器来产生低损耗的横向电模，其中电场平行于墙。这允许在波导中进行非辐射切割，从而允许壁找到它们自己的势能，限制电子向壁的扩散。切割还阻止了等离子体追踪到发电机。最初的实验工作是完全通电的等离子体，最初并不是本科项目的一部分，该项目是开发模式转换器并进行冷测试。由于模式转换器工作正常，我们借用设备进行了热试验。可用的测试时间只有几个小时，由于还没有开发出用于缝隙的微波扼流圈，因此认为微波泄漏的水平如此之高，应该终止实验。等离子体运行了大约30分钟，非常稳定，等离子体容器的裸露铝壁没有变得过热，表明壁面损失很小。在这个项目中，我们初步计划完成扼流圈的开发，这样等离子体就可以运行而不会发生微波泄漏。然后，我们将对等离子体进行表征，并了解如何将其用于加工一系列原料。工业公司将对可能想要使用这项技术的人进行分类，并将被邀请提交样本进行调查。其目标可能是气化、废物销毁、等离子体合成或表面改性。垃圾气化很可能是一项旨在实现温室气体净零排放的重要技术。我们相信，微波等离子体气化对某些有毒废气具有优势。我们还将进行优化工作。

ssues with the scale up of atmospheric pressure Microwave (MW) Plasma Processing, achieving high efficiencies and longevity of components, was identified by a Lancaster Chemical Engineering PhD project using MW plasma torches for the gasification of organic waste.Inspired by STFC funded research, principally Cockcroft Institute grants (2009-2022) STG008248/1 and ST/P002056/1, a solution was proposed by the Lancaster RF accelerator engineers allowing plasmas to be struck in large diameter unlined Nickel steel pipes with greatly reduced wall losses and no tendency for the plasma to track back to the generator. Proof of principle was demonstrated by a subsequent undergraduate project. A patent application has been made. The innovation is to use a mode converter to generate a low loss transverse electric mode where the electric field is parallel to the walls. This allows a non radiating cut to be made in the waveguide that allows the walls to find their own potential limiting electron diffusion to the walls. The cut also stops the plasma tracking back to the generator.The initial experimental work with a fully energised plasma, was not initially planned as part of the undergraduate project, the project was to develop the mode converter and undertake cold testing. As the mode converter worked perfectly, we borrowed equipment to undertake a hot test. The available test time was only a few hours and as the microwave choke for the gap has not been developed, it was deemed that the level of microwave leakage was such that the experiment should be terminated. The plasma was run for about 30 minutes, it was very stable and the bare aluminium walls for the plasma vessel did not become excessively hot indicating low losses to the walls.In this project we plan initially to complete the development of the choke so the plasma can be run without microwave leakage. We will then characterise the plasma and understand how it can be used to process a range of feedstocks. Industrial companies will be sort who may want to use the technology and will be invited to submit samples for investigation. The aims might be for gasification, waste destruction, plasma synthesis or surface modification. Gasification of waste is likely to be an important technology targeting net zero greenhouse gas emission. We believe that microwave plasma gasification offers an advantage for certain toxic waste streams.Optimisation work will also be undertaken.