| OCR Text |
Show American Flame Research Committee International Symposium September 30,1996 information learned by the models to find control solutions which meet the NOx target. These solutions are evaluated versus the constraints (such as CO or LOI) and the performan~e calculation. The optimum set of control settings are selected and displayed. The operator IS responsible for implementing the control changes. Another feature of the control screen is the ability to disable certain controls. The example screen display shown in figure 2, shows the results of disabling the burner tilts. As the figure shows, the InEe n.4 system did not make a recommendation for the burner tilts control setting. Instead, it found the optimum control settings using only the remaining controls. To disable a control, the operator simply clicks on the control setting name, and the InEe n.4 system will no longer attempt to use that control to reduce NOx' This feature allows the InEe n.4 system to be effective even if one or more control options are temporarily out-of-service. The InEC n.4 NOx control screen can also be used to test "what if" scenarios. One "what if" scenario is the effect of taking mills into and out of service. The buttons to the left of the feeder speed controls are used to change mill status. If the button reads ON and the user selects the button, InEe n.4 will simulate the effects of shutting that mill off. After the mill has been turned off, the button will read 0 FE The user can then request the InEe n.4 system to find the optimum control settings for the remaining number of mills in service by selecting the GO button. The other type of "what if" scenario that can be tested is simply to change any of the recommended control settings to a different value. After making a change and selecting the GO button, the InECn.4 system will display the effects of this change on NOx and operating cost. The operator can use this feature to learn the relative effectiveness of his various control options on cost and NOx. NOx Compliance at NYSEG NYSEG elected to operate with a system wide daily NOx Emission cap for the ozone season. NYSEG utilizes a computer program to forecast and track NOx emission during the ozone season to ensure emissions are below the daily cap. Each station is aware of the approximate costs of achieving varying levels of N Ox emission reductions. To implement the program, Power Supply informs each station of the following day's NOx reduction strategy. This strategy can be revised during the day in response to system conditions and operating performance. The generating station's NOx reduction strategies are generally described as Level I and Level II. Level I is a less severe NOx emission reduction with minimal cost impacts. Level II is achieves maximum NOx reductions with limited regard to costs. Load reductions would be required if Level II reductions did not provide compliance with the daily cap. Several factors affect the strategy used each day to comply with the NOx cap. Most notable is the capacity factor. For example, during the 1995 ozone season the capacity factor was high and Level I and Level II NOx reduction strategies were nearly a daily occurrence. In contrast, the 1996 ozone season has seen much lower load levels and NOx reduction requirements have been infrequent. -3- |
