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#BoilerManual #Ramping #Section8 #Page12

The boiler master is increased at a constant rate set by the operator at the MW demand station. Throttle pressure should increase linearly with time, as should MW's, as the 201 valves are opened.

Initially, we will plot the boiler master position relative to 201 valve demand, as shown in Figure 6A, then reference the rest of our curves to 201 and 200 valve actions. Point A is the initial condition just prior to opening the 201 valves. When all of the pre-ramp conditions are satisfied the boiler control should be placed on automatic to the MW demand station between points A and B.

At point B, the turbine is manually increased to 6.5% of full load. The boiler follows with a slight increase in the boiler master signal and the 201 valves open to their initial position. The time between points B and C is a stabilization period allowing the system time to settle out after the introduction of flow through the 201's. If the pre-ramp conditions are correct the system will see very little change and the period between B and C will be short.

When the system has stabilized at point C, the turbine is automated and the MW demand station increased to 33% of its full load value. This initiates th actual pressure ramp, and linearly increases the boiler master from point C to E.

The 201 valves are opened from their initial value at point C to their full open position at point D. The demand for the 201 valve is non-linear as shown in Figure 6A, with the demand signal increasing faster toward the end of the ramp than it does early in the procedure. This provides good flow characteristics by causing the actual flow through the 201's to be nearly linear.

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