Tar moisture control method

The invention belongs to the technical field of coking production, and discloses a tar moisture control method, which is used for separating tar and ammonia water mixed liquor in a tar separation system, and comprises the following steps: S1, starting a centrifugal machine and a centrifugal machine rotary drum, and respectively adjusting the rotating speeds of the centrifugal machine and the centrifugal machine rotary drum to be a first set value and a second set value; s2, when the rotating speed of the centrifuge drum reaches a second set value, a feeding switch and a feeding valve are sequentially opened; s3, starting a tar intermediate pump; s4, adjusting the rotating speed of an oil-water separation regulator of the centrifugal machine and the rotating speed of a centrifugal machine drum; s5, sampling in a tar pipeline at the downstream of the centrifugal machine, and checking whether the moisture of tar is qualified or not; and S6, if the moisture of the tar is qualified, opening a tar conveying pump, a