Conceptualisation, Implementation and Commissioning of a Controlled Pyrolysis Rig : KTH Master Thesis Report

Abstract: Liquid methane has seen popular interest from industry and academia as a next-generation rocket fuel due to its favorable performance characteristics and potential for extra-terrestrial in-situ resource utilisation. Since the rocket combustion chamber and nozzle are subject to high heat loads, regenerative cooling is a standard method to achieve lower temperatures. Hydrocarbon fuels such as methane undergo thermal decomposition when flowing through the regenerative cooling channels resulting in the deposition of a solid carbonlayer along the channel walls. This deposition, which can be catalysed by the channe lmaterial, can lead to reduced engine performance and longevity. An experimental facility equipped with a straight additive-manufactured cooling channel is currently being used at KTH to replicate the phenomena found in real cooling channels. In order to simplify the interpretation of that data and enable rapid characterisation of materials with respect to their deposition behaviour, the current project involves the conceptualisation, implementation and commissioning of a controlled pyrolysis rig. System and sub-system level tests are conducted to characterise and validate the rig’s behaviour and performance. The developed rig is able to pyrolyse methane and deposit solid carbon on heated nickel samples and is able to purge the system with nitrogen. The sample temperature, sample configuration, gas volume flow rate, gas pressure and gas temperature can be measured and all except gas temperature can be actively controlled.