The invention discloses a cleaning process in external cooling gas-transforming alkali preparation. At least two external cooling type carbonizing towers are paralleled into a set; each carbonizing
tower is connected with a set of external coolers; after working for days, each carbonizing
tower is cleaned alternately, and the connected external coolers are also cleaned at the same time. In the cleaning period, other carbonating towers but the one being cleaned continue the alkali preparing work; in cleaning,
ammonia mother liquid 2 is introduced into the cleaned
tower, and at the same time, one part of carbonized exhaust
coming out from the alkali preparing towers is also introduced into the cleaned tower after being pressurized to accelerate
dissolution of
scars in the cleaned tower; the exhaust
coming out from the cleaned tower is combined into the other part of the carbonized exhaust
coming out from the alkali preparing towers and, used as
raw material decarburizing gas for synthetic
ammonia production, is sent with the
ammonia mother liquid 2 discharged out of the cleaned tower into the alkali preparing towers for the alkali preparation. The cleaning process of the invention has no
sewage discharge and does not pollute the environment; in addition, two to six or even more towers can be paralleled into a set for the alkali preparation, thereby significantly improving the working efficiency of the towers and reducing the
adverse effect caused to the production by cleaning operation.