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.