OCR Text |
Show Table 1 - Approximate Achievable Effectiveness of N O x Control Technologies Control Measure Low Excess Air (LEA) Low NOx Burners (LNB) - air staged - fuel staged - Ultra Low NOx Burners (ULNB) - Radiant Flue Gas Recirculation (FGR) FGR + LNB Selective Non-catalytic Reduction (SNCR) Selective Catalytic Reduction (SCR) Overall Effectiveness, % Natural Gas 20 50 60 75 85 57 70 50 80 Distillate Oil 18 45 52 74 - 49 60 50 80 Residual Oil 16 37 37 73 - 35 45 50 90 As indicated in Table 2, the cost effectiveness of combustion controls for new boilers and heaters is relatively low at less than $600/tonne NOx emitted. The cost effectivenes for post-combustion controls is dramatically higher. Table 2 - Cost Comparison of N O x Controls for N e w and Retrofitted Boilers and Heaters* Control Measure LNB ULNB FGR SNCR SCR Capital Cost (K$) For new Boiler/Heater 54.5 92.0 64.0 363.6 708.1 For Retrofit 329.4 366.9 243.4 424.3 1365.8 Cost Effectiveness ($/tonne) For new Boiler/Heater 309 418 557 5451 3993 For Retrofit 3821 3298 3006 7168 9219 • These costs were developed for gas-fired boilers of capacity 100 MMBtu/hr operating at 8 0 % capacity factor. The costs and cost-effectiveness will change according to these parameters (fuel, capacity and load). From the evidence in Tables 1 and 2, it was concluded that the following N O x reductions are achievable at a reasonable cost: Table 3 - Achievable N O , Reduction at L o w Cost Fuel Natural Gas Distillate Oil Residual Oil % NO, Reduction 50 40 25 Technologies LNB LNB LNB % NO, Reduction 70 60 45 Technologies ULNB or FGR & LNB ULNB or FGR & LNB ULNB or FGR & LNB 6 |