The report gives results of an assessment of the feasibility of using automatic controls to maintain a constant percentage SO2 removal in a pressurized fluidized-bed boiler (PFB) system as variations occur; e.g., in coal sulfur content or sorbent reactivity. The Clean Air Act amendments of 1977 indicate that future emission standards for SO2 should be based on a percentage reduction (comparing sulfur emissions with sulfur feed). In a PFB, sulfur feed (coal sulfur content, feed rate) and sulfur removal effectiveness (sorbent reactivity, feed rate) vary continually during operation. A transient model of a PFB plant has been developed, validated, and used to assess automatic control options. The preferred control option identified in the assessment would continuously monitor the sulfur content in the feed coal, and would adjust the sorbent feed rate to maintain a constant sorbent-calcium/coal-sulfur-feed ratio. Such a system would minimize, but not eliminate, the need for excess sorbent feed to ensure that the PFB did not exceed the specified percentage SO2 reduction on a 30-day average. The required techniques to continuously monitor coal sulfur content have not yet been commercially demonstrated.