High-efficient clean, high-variable load rate coal-fired power generation system and operation method thereof

A high-efficient clean, high-variable load rate coal-fired power generation system, comprising a boiler (1), a thermal storage medium heater (2), an economizer (3) and an internal thermal source selective catalytic reduction (SCR) denitration catalytic module (4), wherein:

• the thermal storage medium heater (2), the economizer (3) and the internal thermal source SCR denitration catalytic module (4) are distributed in a flue which is located at a tail portion of the boiler (1) along a flow direction of flue gas in sequence;
• a cold thermal storage medium port of the internal thermal source SCR denitration catalytic module (4) is connected with a first port of a low temperature storage tank (42) through a second thermal storage medium pump (52) and a first thermal storage medium control valve (61), the cold thermal storage medium port of the internal thermal source SCR denitration catalytic module (4) is also connected with the first port of the low temperature storage tank (42) through a third thermal storage medium pump (53) and a second thermal storage medium control valve (62), a hot thermal storage medium port of the internal thermal source SCR denitration catalytic module (4) is connected with a first port of a high temperature storage tank (41), the hot thermal storage medium port is located above the cold thermal storage medium port;
• a cold thermal storage medium inlet of the thermal storage medium heater (2) is connected with a second port of the low temperature storage tank (42) through a first thermal storage medium pump (51);
• a hot thermal storage medium outlet of the thermal storage medium heater (2) is connected with a second port of the high temperature storage tank (41);
• a third port of the high temperature storage tank (41) is connected with a thermal storage medium inlet of a thermal storage feedwater heater (43), a thermal storage medium outlet of the thermal storage feedwater heater (43) is connected with a third port of the low temperature storage tank (42) through a fourth thermal storage medium pump (54), a feedwater inlet of the thermal storage feedwater heater (43) is connected with a feedwater pump (9) through a second feedwater control valve (72), a feedwater outlet of the thermal storage feedwater heater (43) is connected with a feedwater inlet of the economizer (3), the feedwater inlet of the economizer (3) is also connected with the feedwater pump (9) through a first feedwater control valve (71) and a high pressure heater group (8) for steam turbine regenerative system in sequence;
• the internal thermal source SCR denitration catalytic module (4) comprises a heating unit (401) and a catalytic unit (402) connected with the heating unit (401), the heating unit (401) comprises a thermal exchange tube set (403) and a catalyst coating (404) coated on the thermal exchange tube set (403);
• all of the first, second, third and fourth thermal storage medium pumps (51), (52), (53) and (54) are variable frequency pumps;
• the thermal storage medium used in the coal-fired power generation system is thermal conducting oil.