Variable-structure spiral coil boiler reactor

In order to solve the technical problem that the development difficulty of a supply water pump is increased due to large pressure loss of an existing spiral coil type boiler reactor in the steam generation process, the invention provides a variable-structure spiral coil type boiler reactor which comprises a shell, end covers arranged at the two ends of the shell and working medium pipelines arranged between the shell and the end covers. The improvement lies in that the working medium pipeline comprises a first pipe section, a second pipe section, a third pipe section and a fourth pipe section which are sequentially connected in series from the liquid water inlet to the steam outlet; the first pipe section is a straight pipe or a spiral coil pipe; the second pipe section, the third pipe section and the fourth pipe section are spiral coil pipes; liquid water flows through the first pipe section and the second pipe section to form saturated water, flows through the third pipe section to form dry saturated steam