Coal power plant having an associated co2 scrubbing station and heat recovery

Abstract

The invention relates to a method for recovering heat by joining a plurality of heat flows of a fossil-fired, in particular carbon-fired, power plant ( 1 ), which downstream of the combustion comprises a CO 2 scrubbing station ( 58 ) for the flue gas by way of chemical absorption and/or desorption and associated CO 2 compression ( 27 ), which method aims to enable a CO 2 scrubbing station for the flue gas, with associated CO 2 compression, to be integrated into the total energy heat flow and/or the total heat energy balance of a fossil-fired, in particular carbon-fired, preferably conventional, power plant in a way that is advantageous in terms of heating technology. This is achieved by decoupling thermal energy from the heat flow of the CO 2 scrubbing station ( 58 ), with associated CO 2 compression, in the form of at least one partial heat flow (Q 8 , Q 9 , Q 10 , Q 11 ) and coupling it back into a heat flow that is coupled, directly or indirectly, to the heat flow of the boiler ( 2 ) or steam generator of the power plant ( 1 ), and/or by decoupling thermal energy from the flue gas heat flow (Q 3 ) in the form of a partial heat flow (Q 12 , Q 13 , Q 14 ) and coupling it back into the heat flow of the CO 2 scrubbing station ( 58 ) with associated CO 2 compression ( 27 ).

1 . A method for heat recovery by connecting a plurality of heat streams of a fossil-fired power plant to a CO 2  scrubbing station which is downstream of the combustion and is for the flue gas by means of chemical absorption and/or desorption and associated CO 2  compression, wherein from the heat stream of the CO 2  scrubbing station with associated CO 2  compression, thermal energy in the form of at least one heat substream is extracted and fed back into a heat stream that is coupled directly or indirectly to the heat stream of the boiler or steam generator of the power plant and/or wherein from the flue gas heat stream, thermal energy in the form of at least one heat substream is extracted and fed back into the heat stream of the CO 2  scrubbing station with associated CO 2  compression. 
     
     
         2 . The method as claimed in  claim 1 , wherein thermal energy available in the region of the CO 2  scrubbing station with associated CO 2  compression is decoupled or extracted from the heat stream of the CO 2  scrubbing station with associated CO 2  compression as a heat substream by at least one first plant component that is utilizable there as a heat source, and/or thermal energy available in the region of a flue gas line is decoupled or extracted from the heat stream of the flue gas by at least one second plant component that is utilizable there as a heat source and the thermal energy in the region of the power plant obtained respectively by the decoupling or extraction in the form of the at least one heat substream is fed back into the heat stream of the power plant outside the respective decoupling or extraction region by at least one further plant component that is utilizable there in each case as heat sink for the thermal energy obtained. 
     
     
         3 . The method as claimed in  claim 1 , wherein thermal energy available in a CO 2 -rich gas stream and/or in the absorption medium used is decoupled or extracted in the region of the CO 2  scrubbing station with associated CO 2  compression. 
     
     
         4 . The method as claimed in  claim 1 , wherein thermal energy available in the flue gas is decoupled or extracted in the region of the flue gas line and/or in the region of a bypass flue gas line bypassing an air preheater. 
     
     
         5 . The method as claimed in  claim 1 , wherein the thermal energy that is decoupled or extracted in the region of the CO 2  scrubbing station with associated CO 2  compression is fed back into the heat stream of the power plant outside the region of the CO 2  scrubbing station with associated CO 2  compression. 
     
     
         6 . The method as claimed in  claim 1 , wherein the thermal energy which is decoupled or extracted in the region of the flue gas line and/or in the region of the bypass flue gas line is fed back into outside the region of the flue gas line and/or the bypass flue gas line the water-steam circuit and/or the district heating circuit and/or the region of the CO 2  scrubbing station with associated CO 2  compression. 
     
     
         7 . The method as claimed in  claim 1 , wherein the thermal energy is decoupled or extracted by one or more heat sources formed at the CO 2  scrubbing station desorber or regenerator head and/or downstream of the CO 2  compression in the CO 2  flow direction and/or in the region of the CO 2  scrubbing station absorber intercooler and/or in the region of the CO 2  compression intercooler, and the thermal energy is fed back in by means of one or more heat sinks formed in the region of the low-pressure preheater and/or in the condensate flow direction upstream of the low-pressure preheater and/or in a district heating circuit and/or in a fresh air heater and/or in a coal drying station and heat-energy-conductingly connected to the heat source(s). 
     
     
         8 . The method as claimed in  claim 1 , wherein the thermal energy is decoupled or extracted by one or more heat sources formed in the flue gas line and/or in the bypass flue gas line and the thermal energy is fed back into the water-steam circuit in the region of the low-pressure preheater and/or the high-pressure preheater and/or into the district heating circuit and/or into the region of the CO 2  scrubbing station. 
     
     
         9 . The method as claimed in  claim 1 , wherein the thermal energy which is decoupled or extracted in the region of the CO 2  scrubbing station with associated CO 2  compression is fed back into the heat stream of the power plant by heat exchangers arranged in a Rankine cycle. 
     
     
         10 . The method as claimed in  claim 1 , wherein the method is carried out in a power plant as claimed in  claim 11 . 
     
     
         11 . A power plant having a CO 2  scrubbing station which is downstream of the combustion and is for the flue gas by chemical absorption and/or desorption and associated CO 2  compression, wherein at least one first plant component that is utilized as a heat source and which effects the decoupling or extraction of thermal energy from the heat stream of the CO 2  scrubbing station with associated CO 2  compression is arranged and/or is formed in the region of the CO 2  scrubbing station with associated CO 2  compression and/or at least one second plant component that is utilized as a heat source and which effects the decoupling or extraction of thermal energy from the flue gas stream is arranged and/or formed in the region of a flue gas line and/or a bypass flue gas line bypassing an air preheater, and at least one third plant component that is heat-energy-conductingly connected to said plant component and is also utilized as a heat sink and effects the feeding back into of the decoupled or extracted thermal energy the heat stream of the power plant outside the respective decoupling or extraction region is arranged and/or formed in the region of the power plant. 
     
     
         12 . The power plant as claimed in  claim 11 , wherein one or more of the first plant components utilized as heat source(s) for heat transfer is/are arranged and/or formed at the CO 2  scrubbing station desorber or regenerator head and/or downstream of the CO 2  compression in the CO 2  flow direction and/or in the region of the CO 2  scrubbing station absorber intercooler and/or in the region of the CO 2  compression intercooler, each of which first plant components is heat-energy-conductingly connected in a manner bearing a heat-carrier medium to one or more plant components arranged in the region of the low-pressure preheater and/or in the condensate flow direction upstream of the low-pressure preheater and/or in a district heating circuit and/or in the fresh air heater and/or in the coal drying station and, as heat sink(s), effecting a heat transfer. 
     
     
         13 . The power plant as claimed in  claim 11 , wherein at least one first plant component forming a heat source is formed and is connected in the manner heat-energy-conductingly bearing a medium to at least one further plant component arranged in the region of the power plant forming a heat sink wherein one or more of the first plant components selected from a heat exchanger at the CO 2  scrubbing station desorber or regenerator head and/or a heat exchanger downstream of the CO 2  compression and/or a heat exchanger of the CO 2  scrubbing station absorber intercooler and/or a heat exchanger of the CO 2  compression intercooler each forms a heat exchanger acting as a heat source, and/or a line conducting high CO 2 -content gas downstream of a desorber forms a plant component utilized as a heat source, and/or a line conducting liquid CO 2  downstream of the CO 2  compression forms a plant component utilized as a heat source, and also one or more of the further plant components selected from a heat exchanger of the low-pressure preheater and/or a heat exchanger upstream of the low-pressure preheater and/or a heat exchanger in the district heating circuit and/or a heat exchanger of the coal drying station and/or a heat exchanger of the fresh air heater each forms a further heat exchanger acting as heat sink. 
     
     
         14 . The power plant as claimed in  claim 11 , wherein the heat exchanger forming a heat source at the CO 2  scrubbing station desorber or regenerator head is heat-energy-conductingly connected to a heat exchanger, forming a heat sink, of the low-pressure preheater. 
     
     
         15 . The power plant as claimed in  claim 11 , wherein the heat exchanger forming a heat source is heat-energy-conductingly connected downstream of the CO 2  compression to a heat exchanger, forming a heat sink, of the low-pressure preheater. 
     
     
         16 . The power plant as claimed in  claim 11 , wherein the heat exchanger, upstream of the low-pressure preheater, is arranged in a condensate line downstream in the condensate flow direction of a condensate pump, and/or the heat exchangers of the low-pressure preheater are arranged in a bypass line branching off from the condensate line. 
     
     
         17 . The power plant as claimed in  claim 11 , wherein the return of the heat exchanger of the low-pressure preheater is heat-energy-conductingly connected to the flow of the heat exchanger upstream of the low-pressure preheater. 
     
     
         18 . The power plant as claimed in  claim 11 , wherein a heat-carrier medium is conducted in a circuit formed by the heat exchanger downstream of the CO 2  compression, the heat exchanger next to a feed water container in the condensate flow direction and the heat exchanger upstream of the low-pressure preheater and/or is conducted in a circuit formed by the heat exchanger at the CO 2  scrubbing station desorber or regenerator head and the heat exchanger next to a condensate pump positioned in the upstream-side condensate flow direction, in each case through these heat exchangers. 
     
     
         19 . The power plant as claimed in  claim 11 , wherein the heat exchanger at the CO 2  scrubbing station desorber or regenerator head and/or the heat exchanger downstream of the CO 2  compression is/are heat-energy-conductingly connected to one or more heat exchangers arranged in the district heating circuit. 
     
     
         20 . The power plant as claimed in  claim 19 , wherein one or more of the heat exchangers arranged in the district heating circuit is/are heat-energy-conductingly connected to one or more of the heat exchangers associated with or arranged upstream of the low-pressure preheater. 
     
     
         21 . The power plant as claimed in  claim 19 , wherein the heat exchanger upstream of the low-pressure preheater is arranged in the return of the heat exchanger arranged in the district heating circuit and/or in the return of the heat exchanger associated with the low-pressure preheater. 
     
     
         22 . The power plant as claimed in  claim 11 , wherein the heat energy supply for the reboiler or evaporator is constructed to be integrated into the district heating circuit. 
     
     
         23 . The power plant as claimed in  claim 11 , wherein the heat exchanger at the CO 2  scrubbing station desorber or regenerator head and/or the heat exchanger downstream of the CO 2  compression is/are heat-energy-conductingly connected to one or more heat exchangers arranged in a power plant coal line connected to a coal mill. 
     
     
         24 . The power plant as claimed in  claim 11 , wherein the heat exchanger at the CO 2  scrubbing station desorber or regenerator head and/or the heat exchanger downstream of the CO 2  compression is/are heat-energy-conductingly connected to one or more heat exchangers arranged in a fresh air line feeding fresh air to the boiler of the power plant. 
     
     
         25 . The power plant as claimed in  claim 11 , wherein at least one heat exchanger arranged in the bypass flue gas line is heat-energy-conductingly connected to the water-steam circuit of the power plant in the region of the low-pressure preheater or the high-pressure preheater. 
     
     
         26 . The power plant as claimed in  claim 11 , wherein a heat exchanger arranged in the bypass flue gas line is heat-energy-conductingly connected to the district heating circuit. 
     
     
         27 . The power plant as claimed in  claim 11 , wherein a heat exchanger arranged in the bypass flue gas line is heat-energy-conductingly connected to the reboiler and/or to a heat exchanger of the reboiler. 
     
     
         28 . The power plant as claimed in  claim 11 , wherein a heat exchanger heat-conductingly connected to the district heating circuit and/or a heat exchanger heat-conductingly connected to the water-steam circuit of the power plant is arranged in the reboiler return. 
     
     
         29 . The power plant as claimed in  claim 11 , wherein the heat exchanger at the CO 2  scrubbing station desorber or regenerator head and/or the heat exchanger downstream of the CO 2  compression and/or the heat exchanger of the CO 2  scrubbing station absorber intercooler and/or the heat exchanger of the CO 2  compression intercooler is/are heat-conductingly connected to a heat exchanger arranged in a Rankine cycle. 
     
     
         30 . The method for heat recovery as recited in  claim 1 , wherein the fossil-fired power plant comprises a coal-fired power plant. 
     
     
         31 . The method as recited in  claim 5 , wherein the thermal energy that is decoupled or extracted in the region of the CO 2  scrubbing station with associated CO 2  compression is fed back into the heat stream of the power plant into the water-steam circuit and/or a district heating circuit and/or into a coal-bearing coal line and/or a fresh air line. 
     
     
         32 . The method as claimed in  claim 6 , wherein the thermal energy which is decoupled or extracted in the region of the flue gas line and/or in the region of the bypass flue gas line is fed back into a heat exchanger of a reboiler. 
     
     
         33 . The method as claimed in  claim 8 , wherein the thermal energy is fed back into the reboiler. 
     
     
         34 . The method as claimed in  claim 33 , wherein the thermal energy is fed back into a heat exchanger of the reboiler. 
     
     
         35 . The power plant of  claim 11 , wherein the power plant is fossil-fired. 
     
     
         36 . The power plant of  claim 11 , wherein the power plant is coal-fired. 
     
     
         37 . The power plant of  claim 11 , wherein a plurality of third plant components that are heat-energy-conductingly connected to said plant component and re also utilized as a heat sink and effect the feeding back into of the decoupled or extracted thermal energy the heat stream of the power plant outside the respective decoupling or extraction region re arranged and/or formed in the region of the power plant. 
     
     
         38 . The power plant as recited in  claim 13 , wherein the at least one first plant component comprises a heat exchanger. 
     
     
         39 . The power plant as recited in  claim 13 , wherein the at least one first plant component is for a separate heat-carrier medium. 
     
     
         40 . The power plant as recited in  claim 13 , wherein the at least one first plant component is formed and is connected in the manner heat-energy-conductingly bearing a separate heat-carrier medium. 
     
     
         41 . The power plant as recited in  claim 13 , wherein the at least one further plant component comprises a further heat exchanger. 
     
     
         42 . The power plant as recited in  claim 13 , wherein the at least one further plant component forms a heat sink for the separate heat-carrier medium. 
     
     
         43 . The power plant as recited in  claim 14 , wherein the heat exchanger forming a heat source at the CO 2  scrubbing station desorber or regenerator head is heat-energy-conductingly connected, to the heat exchanger next to a condensate pump positioned on the upstream side to the condensate flow direction. 
     
     
         44 . The power plant as recited in  claim 15 , wherein the heat exchanger forming a heat source is heat-energy-conductingly connected downstream of the CO 2  compression to the heat exchanger next to a feed water container in the condensate flow direction, and/or with the heat exchanger, forming a heat sink, upstream of the low-pressure preheater. 
     
     
         45 . The power plant as recited in  claim 28 , wherein the heat exchanger heat-conductingly connected to the district heating circuit and/or a heat exchanger heat-conductingly connected to the water-steam circuit of the power plant, is in the region of the low-pressure preheater.