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Construction ceramic industry flue gas ultra-low emission SCR denitration technology and equipment
Applicating Company
Shandong Tiantuo Equipment Manufacturing Co., Ltd
Technology Name
Construction ceramic industry flue gas ultra-low emission SCR denitration technology and equipment
Technical principle
The whole form of SCR is called the selective catalytic reduction method (Selective Catalytic Reducation).
The catalytic reduction method is to use a reducing agent such as ammonia or urea, which reduces the NOx (NO, NO2) in the exhaust gas through the catalyst at a certain temperature, and transforms the NOx into the non-polluting element molecule nitrogen (N2). The reaction of NOx and ammonia is as follows:
4NO + 4NH3 + O2 → 4N2 + 6H2O
6NO2+8NH3→7N2+12H2O
Scope of application
The nitrogen oxide content in the flue gas is reduced from the initial 500mg / Nm3 to below 30mg / Nm3, reaching the local standard of Shandong Province DB37 / 2373-2018 Building Materials Industry Air Pollutant Emission Standard and DB72376-2019 Shandong Province regional air pollutant emission standard are applicable to the construction ceramic sanitary ware industry and various industrial kilns.
Process flow and description
The smoke exhaust temperature of the tunnel kiln is 120~140℃, heat exchange to 160~170℃ through the efficient heat exchanger, rises to 230℃ through the gas burner, meets the reaction temperature conditions of the low temperature SCR catalyst, and enters the SCR reactor together with the ammonia grid and mixed ammonia.Due to heat loss, the flue temperature drops to about 200~210℃, and the heat exchange of the heat pipe heat exchanger drops to about 140℃ to enter the subsequent process.
Suitable ammonia concentration solution (20% mass concentration) is discharged into the ammonia storage tank through the tank.One ammonia solution storage tank (304 stainless steel with pressure test pressure is 0.2MPa, actual maximum working pressure is 0.03MPa) and the tank capacity is 11m3There are 2 ammonia pumps (1 with 1 standby) to deliver the ammonia water to the ammonia evaporator through the flow automatic regulation system.The ammonia water evaporator of this project uses the hot flue gas after the heat induction furnace and mixing ammonia. The diluted ammonia (the diluted ammonia concentration is reduced to 5%) is sent to the ammonia grille through the buffer tank. The distance between the ammonia grille and the SCR catalyst shall not be less than 8m, and the spoiler and rectifier grille are added to fully mix the ammonia and the flue gas to be treated.The flue gas to be treated is heated by a low nitrogen burner, and the flue gas temperature is controlled at 230℃ (design adjustment range of 180~350℃). The fully mixed flue gas produces a catalytic reduction reaction to generate harmless nitrogen and water. To prevent the fly ash in the flue gas, a set of acoustic ash blowers is about 500mm from the catalytic top of each layer and work regularly.
Promotion prospects
SCR is fully known as selective catalytic reduction method (Selective Catalytic Reducation), which has developed rapidly in recent years. Western Europe and Japan have been widely used. At present, ammonia catalytic reduction method is the most used technology.It has no by-products, does not form secondary pollution, simple device structure, and high removal efficiency (up to over 90%), reliable operation, easy maintenance and other advantages.