Dust Removal, Desulphurization and DeNOx Technology of FCC Flue Gas

Transcription

1 Dust Removal, Desulphurization and DeNOx Technology of FCC Flue Gas Presented By: Fushun Research Institute of Petroleum and Petrochemicals,SINOPEC Liu Zhongsheng Contents 1 Control Standards of FCC Flue Gas 2 Dust Removal, Desulphurization and DeNOx for FCC Flue Gas 3 SCR DeNOx Process 4 Dust Removal and Desulphurization Process 5 Industrial Plant 6 Summary 2

2 1 Control Standards of FCC Flue Gas Standards Dust,mg/Nm 3 SO 2,mg/Nm 3 NOx,mg/Nm 3 USA, EPA 40CFR Europe 10~30 20 ~ China, GB Some province or city in China Dust Removal, Desulphurization and DeNOx for FCC Flue Gas NH 3 -SCR (Selective catalytic reduction) Caustic soda solution scrubbing FCC Flue Gas DeNOx Unit Dust & SOx Removal Unit Emission to air

3 3 SCR DeNOx Process a) FCC flue gas denox process include selective catalytic reduction (SCR), selective non catalytic reduction (SNCR) and ozone oxidation absorption etc; we adopted SCR. b) SCR process: ammonia supply, catalytic reaction and utility; c) NH 3 is diluted by air to 5%(v). The mixture gas is heated to higher than 120 and sprayed into the flue gas by the ammonia spray nozzle. NH 3 and the flue gas are mixed completely by the mixture grid. d) We developed honeycomb catalyst of V 2 O 5 -WO 3 /TiO 2. e) Catalytic reactor (bed) is installed in the area of 320 to 420 in the heat recovery boiler or CO boiler. 3 SCR DeNOx Process Liquid ammonia Ammonia buffer tank Dilution gas Hot water Liquid ammonia evaporator Static mixer Flue gas Catalyst layers DeNOx reactor To economizer

4 SCR Key Techniques (1) Highly effective denox catalyst. (2) Simulation calculation of the flow field of the denox reactor, etc. (3) The internal components, gas-gas mixture grid, etc. SCR Catalyst SCR DeNOx Reaction Temp: SV: h -1

5 Honeycomb SCR Catalyst Direct extrusion W, Ti, V, Binder, etc. Mixing Pugging Extruding 9 To develop catalyst in the laboratory 10

6 Commercial SCR catalyst Production operation Production operation 11 FRIPP has FN-1 FN-2 FN-2G catalyat,etc. Catalyst sample Modularization catalyst 12

7 Modularization catalyst installation Injection of ammonia Flue gas inlet --Supporting catalyst --Space for adding reserved catalyst --Ensure uniform distribution of flue gas --Sealing device --Ash blower Flue gas outlet 阻流板 Choke flow plate Catalyst layers 反应器壁 Reactor wall 13 Optimum reactor shape and flue gas pipe Optimum FCC SCR Reactor velocity streamline

8 Ammonia spray nozzle, Gas-gas mixture grid Ammonia spray nozzle Gas-gas mixture grid 4 Dust Removal and Desulphurization Process a) FCC flue gas dust removal and desulfurization process include sodium alkali solution scrubbing, ammonia solution scrubbing, magnesium hydroxide slurry scrubbing and so on. We adopted NaOH solution scrubbing process; b) Dust removal and desulphurization by using two-stage scrubbing technology. The first stage was quench & prior dust removal and desulphurization tower, in which Venturi grid or reverse spraying nozzles were installed. The temperature of flue gas was rapidly decreased to about 60 and most of dust and SO 2 were removed in this stage. The second stage was unified tower, in which dust and SO 2 were further removed, gas and liquid were separated. 16

9 4 Dust Removal and Desulphurization Process Supplementary water Water sealed tank FCC flue gas Defoaming slurry circulating pump Bulging drum filter From alkaly slurry tank Waste water pipe Fresh water Oxidation tank Emergency cooling water Mud to outside of boundary zone Alkaly slurry Tower Dewater device quench & dust removal tower Oxidation fan Alkaly slurry tank Alkaly slurry pump Reverse spraying Reverse spraying slurry circulating pump circulating pump Venturi grid slurry circulating pump Metering pump Buffer tank Coagulation agent tank Vaccum pump 17 Convetion Venturi scrubber The diameter of Venturi is limited. Several Venturi tubes were needed when disposing large gas flow. Venturi tube is very high.?

10 To develop Venturi grid scrubber Dust removal and desulphurization by Turbulent reverse spraying atomization 雾化区 area bubbling 鼓泡区 area Gas flow 气体流量 foam 泡沫区 area layering 分层区 area 液气比 liquid gas ratio (l/nm 3) (l/nm 3 )

11 5 Industrial Plant In 2012, the Industrial plant of dust removal, desulphurization with sodium alkali and DeNOx by SCR for FCC flue gas was built in 1.8Mt/yr FCC Unit of Zhenhai Refining & Chemical Company by Fushun Research Institute of Petroleum and Petrochemicals (FRIPP),Zhenhai Refining and Chemical Company, Ningbo Engineering Company and Luoyang Engineering Company. The plant has been running steady today. SCR Reactor

12 Desulphurization Unit Dust Removal & Desulphurization waste water treatment Waste water filter Sludge dewatering Vacuum filer Waste water oxidation reactor

13 Industrial plant-standardization ( ~ ) Sample Outlet Flue gas Outlet waste water Analysis item Dust ph COD SS TDS NH3-N Unit mg/nm 3 mg/l mg/l mg/l mg/l Design data <50 6~9 <60 <70 < am < pm < am SO 2 mg/nm 3 < NO x mg/nm 3 < < pm < am < pm < Inlet and Outlet NOx Concentration NO X Concentration ( mg/nm 3 ) Inlet Outlet

14 Inlet and Outlet SO 2 concentration Inlet SO 2 Concentration ( mg/nm 3 ) Inlet Outlet Outlet SO 2 Concentration ( mg/nm 3 ) Outlet Dust Concentration Dust Concentration ( mg/nm 3 )

15 6 Summary Under better work conditions, the dust concentration of purified flue gas was less than 20 mg/m 3, SO 2 was less than 20 mg/m 3, NOx was less than 50 mg/m 3 (minimum NOx under 20mg/m 3 ), COD of desulphurization waste water was less than 60 mg/l, suspended substance of desulphurization waste water was less than 60 mg/l, which can meet the national and local standards. The technology has been applied in near 30 units, and some new sets are building. Thank you for your attention! 30