Question 151Steam Plants - Assistant Engineer

The correct answer is D) reduce the steam supply pressure to the soot blower element. The pressure control disk installed in the multi-nozzle soot blower is designed to reduce the high-pressure steam supply to a lower pressure suitable for the soot blower's operation. This helps prevent damage to the soot blower components by limiting the pressure exerted on the system. The other answer choices are incorrect because they do not accurately describe the purpose of the pressure control disk. Option A refers to controlling the pressure on the valve spring retainer, which is not the primary function of the pressure control disk. Options B and C are also incorrect, as the disk is not intended to control the pressure exerted on the steam valve disk or increase the pressure in the steam supply line.