With reference to the figure, answer the following questions using your own words, and the instrument and control loop identifiers and numbering system from the P&ID. (a) Describe the control system that regulates the pressure within the interior of the boiler (including the furnace volume) in a short paragraph. Include in your answer, the regulation of airflow into, and exhaust gases out, of the boiler interior. (b) Are there any examples of cascade control shown on the P&ID? If so, describe all of them. (c) Describe how the air/fuel ratio is controlled on the burner in a short paragraph. How is the excess oxygen monitored in the flue gas? Can the air/fuel ratio control system be improved, if so, how? AUTO SP 50% PV: 50% OP% 50% LCV-401 LIC LP 401 Steam LRY 401 Treated water LAL 4017 35% Vent Stack 450F LT LE Deaerator 402/ -.02 P 400 PR 402 V-402A P-402 SP 50% PV: 50% OP% 50% AUTO SP -.05 PV: -.05 OP% 100% AUTO /PIC Fan-402B 4028/ Desuperheated V-402E W 155 psig Pi (402 PCV-4028 FCV-402C V-402B 305F 60 psig TEPI PAHI 75 404 403 404 Low 50 psig psig 402 35% LR 4027 (LTLE LIC 402, TE 401 500F: FE FT) V-40 X- FIC 402C/ Ai 402 AA Hi 402 .......... PT PE V-41 Boiler-402 Low 0-10% Oxygen SP 150 GPM PV 150 GPM OP%: 25% CASC V-402C V-402D SP 50% PV: 50% OP% 50% AUTO Superheated TE 350F40 TR 402 350F FIC 402B on/off BA 402/ Burner-402 D FT FE -.02 404) FCV-402B PE PT PIC 402A/ 60 psig Pi 401 150 psig Hi PCV-402A 401 Low AUTO SP 120 psig PV 120 psig OP% 25% PA 100 psig FIC 402A/ TE 400 600F GO FT FE To Ex-205 # per hour of steam required at full load. AUTO SP 50% PV 50% OP% 50% Fan-402A TK-402 Natural Gas Tank