Hydrocarbon compound synthesis reaction unit and operating method thereof

A hydrocarbon compound synthesis reaction unit for synthesizing a hydrocarbon compound by a chemical reaction of a synthesis gas including hydrogen and carbon monoxide as main components, and a slurry having a solid catalyst suspended in liquid hydrocarbons, the hydrocarbon compound synthesis reaction unit comprising:

• a reactor which is configured to contain the slurry inside, into which the synthesis gas can be introduced, and from which the gas after the reaction can be discharged from the top thereof;
• an internal separation device provided inside the reactor to separate the catalyst and the liquid hydrocarbons in the slurry;
• and
• an external separation device provided outside the reactor for separating the catalyst and the liquid hydrocarbons in the slurry which is extracted from the reactor, wherein
• the unit is configured to switch operation so that the internal separation device and the external separation device can be simultaneously or alternatively used, wherein
• the unit further comprises:
• a return flow line installed between the external separation device and the reactor, and configured to transfer the slurry separated by the external separation device to the reactor;
• a slurry container connected to a branch line which branches from the return flow line, and to which the slurry is transferred from the external separation device;
• and
• a nitrogen gas introduction device installed on the return flow line, and configured to introduce nitrogen gas to transport the slurry to the slurry container after the external separation device is stopped and before the internal separation device is operated.