Although the Fischer-Tropsch Synthesis (FT Synthesis) process is well known and at face value quite simple, it is quite complicated to use for DIY production of a somewhat defined length hydrocarbon. This is the subject of a recent video by [Hyperspace Pirate]in which he goes over the correct alpha value for his FT reactor to not only create the equivalent of crude oil.
This alpha value is determined by the temperature and pressure in the reactor, as the syngas – made up of carbon monoxide and hydrogen – is encouraged by the catalyst material to turn into the right carbohydrates. At very low alpha values this process will be completed very quickly, mostly methane (CH4), while a higher number creates increasingly long carbohydrate chains before ending with their last hydrogen molecules.
Since this process is exothermic, this creates many exciting opportunities to ruin a production batch unless you can somewhat control the temperature and pressure in the reactor vessel. In the video, a heater is used to kickstart the reaction before turning it off. As a catalyst, an iron-based material is created that is packed in the steel tube that forms the reactor vessel.
Through this the syngas is passed, with the initial experiments producing a few ml of what appears to be pentane and hexane, with the rest apparently being gaseous methane, ethane and the like. This indicates a relatively low alpha value, which is not ideal if your goal is to synthesize a specific hydrocarbon. Given how complex this process is, there is a good argument to be made that using FT synthesis at a high alpha to exclude crude for standard distillation is the simpler method.