The invention relates to the technical field of
argon graded replacement, in particular to an
argon graded
replacement method for synthesizing n-
butyllithium. Comprising the following steps: arranging a gas accommodating cavity between adjacent reaction kettles, and controllably communicating the gas accommodating cavity with a gas outlet of a front-stage reaction kettle and a gas inlet pipeline of a rear-stage reaction kettle through a control valve group; firstly, pretreatment equipment (a
branch pipe) of a single kettle is started,
argon is introduced,
mixed gas in a pipeline blind area is removed, then the argon
time sequence and flow of upstream, downstream and
midstream gas inlets are controlled, a stable pressure gradient is formed, and the
mixed gas in the kettle is directionally pushed to a gas containing cavity;
mixed gas in the front-stage gas accommodating cavity is introduced into the rear-stage kettle for repeated replacement and is finally discharged from the
tail end; according to the method, blind area purification is enhanced, the replacement efficiency is improved, argon consumption is reduced,
inert gas waste is reduced, carbon emission reduction is assisted, and
atmospheric pollution prevention and control are assisted.