DOUBLE REHEATING UNIT HAVING ULTRA-HIGH-PRESSURE CYLINDER AND HIGH-PRESSURE AND INTERMEDIATE-PRESSURE CYLINDER EACH HAVING ADDITIONAL HEAT REGENERATION STAGES

摘要

A double reheating unit having an ultra-high-pressure cylinder and a high-pressure and intermediate-pressure (HP-IP) cylinder each having additional heat regeneration stages, comprising: a boiler water wall and economizer (1), a boiler superheater system (2), an ultra-high-pressure cylinder (3) having additional heat regeneration stages, a boiler primary reheating system (4), an HP-IP cylinder (5) having additional heat regeneration stages, a boiler secondary reheating system (6), an intermediate-pressure and low-pressure (IP-LP) cylinder (7), an air heater (8), an air heater drainage pump (9), a condenser (10), a condensate pump (11), a ultra-low-temperature economizer (12), a deaerator (13), an electric feedwater pump (14), and high-pressure heaters 1-4. The ultra-high-pressure cylinder (3) comprises an all-pressure-stage impeller of the ultra-high-pressure cylinder, a nozzle, and a steam distribution mechanism. A steam exhaust hood becomes a large steam extraction opening. Five short-vane pressure stages are newly added after the steam exhaust hood. Divided steam continues to expand and exert effect in the newly-added pressure stages, and low-enthalpy extraction steam having a low degree of superheat is output respectively from new second, third, and fourth extraction ports. A first exhaust steam extraction of the ultra-high-pressure cylinder (3) supplies steam to high-pressure heater 1 (18). The new second, third, and fourth extractions of the ultra-high-pressure cylinder (3) supply steam to high-pressure heaters 2, 3, and 4 respectively. A new fifth extraction of the HP-IP cylinder (5) supplies steam to the deaerator (13). A new sixth extraction of the HP-IP cylinder (5) supplies steam to the air heater (8). The air heater drainage pump (9) used for water draining of the air heater (8) connects to the deaerator (13). Through the further optimization of regenerative systems, the heat consumption of ultra-supercritical grade double reheating units can be markedly reduced, as can greenhouse gas emissions.