System beneficial to yield increase of circulating fluidized bed gasifier

The utility model discloses a system beneficial to yield increase of a circulating fluidized bed gasifier, which comprises a nitrogen making machine, a tail gas exhaust pipe of the nitrogen making machine is provided with branch pipes respectively connected with a low-concentration collecting tank and a high-concentration collecting tank, and the tail gas exhaust pipe is provided with a pressure transmitter. A choke valve, a concentration difference regulator and a centrifugal fan are arranged on the branch pipe connected to the low-concentration collecting tank, a vertical check valve is arranged on the branch pipe connected to the high-concentration collecting tank, a communicating pipe is arranged between the low-concentration collecting tank and the high-concentration collecting tank, a linear regulating valve is arranged on the communicating pipe, and a water inlet pipe is arranged on the communicating pipe. An oxygen-enriched conveying pipe connected to an air blower is arranged on the low-concentration