Q. Firing Rate Demand for Steam Generator?
The firing rate for each Steam Generator is proportional to the feedwater flowing into that Steam Generator. Thus, the sum of the pass flows to each Steam Generator is the wild flow to a ratio controller that will automatically adjust the firing to reflect changes in load. A separate ratio controller has to be provided for each Steam Generator, since the loadings may be different. The operator would be responsible for adjusting the ratio setpoints to compensate for fluctuations in steam density and calorific value of the fuel gas.
Each ratio controller output represents the firing demand for that Steam Generator. Subsequent controls on air and gas follow the same structure for each Steam Generator.