Ammonia flow rate fine control device of solid selective catalytic reduction (SSCR) system

The invention relates to an ammonia flow rate fine control device of a solid selective catalytic reduction (SSCR) system. The ammonia flow rate fine control device mainly comprises an SSCR ammonia generator (2), a pressure stabilizing tank (8), a coarse and fine regulation combined control valve (15), an SCR (selective catalytic reduction) catalytic converter (16) and an ammonia spraying control unit (4). The coarse and fine regulation combined control valve (15) comprises a high-frequency on-off control valve I (10), a high-frequency on-off control valve II (18) and a butterfly control valve (13), and the butterfly control valve (13) is positioned on a main gas outlet channel (12); the ammonia spraying control unit (4) controls the high-frequency on-off control valve I (10) in a coarse regulation channel (9) at first, and then the ammonia spraying control unit (4) can select one fine regulation device or two fine regulation devices, so that the ammonia flow rate can be finely regulated by the single fine regulation device or can be finely regulated by the two fine regulation devices simultaneously, and one fine regulation device does not work when the ammonia flow rate is regulated by the other fine regulation device.