The invention discloses a process and a
system for preparing
ammonia from
ammonium bicarbonate by using a wet process for
flue gas denitration, belonging to the technical field of
flue gas denitration in a thermal power
plant. In the process, an
ammonium bicarbonate solution at 90 DEG C is boosted and then enters an atomizing
nozzle of a pyrolyzing furnace for
backflow ejection, fogdrop of the
ammonium bicarbonate decompose out
ammonia gas under the heating action of high-temperature
flue gas flowing from bottom to top, and the residual
ammonium bicarbonate solution converges at the bottom of the pyrolyzing furnace and then returns to a
dissolution pool through a
circulating pump for recycling; and the
ammonia gas flows to a
buffer tank together with air, enters an
ammonia gas-air mixer and then enters an SCR (
Selective Catalyst Reduction) reactor through an ammonia-spraying
grating after being diluted to certain concentration, and in the presence of a catalyst, the
ammonia gas reduces
NOX into N2. The
ammonium bicarbonate is a
reducing agent which is convenient and safe to transport and store, has better economy than
urea and avoids the potential safety
hazard of the reducing agents of
liquid ammonia, ammonia water and the like in the aspects of transportation and storage. By adopting the
ammonium bicarbonate as the
reducing agent to pyrolyze for preparing the ammonia with the wet process, the whole
system has the advantages of easy dosage control of the ammonium bicarbonate, stable
ammonia gas generation, simplicity and high efficiency.