Power plant with co2 capture and water treatment plant

Abstract

A power plant for the generation of electrical energy comprises steam and/or gas turbines ( 2, 3, 4, 13 ) driven by fossil fuels and a CO2 capture system ( 20 ) for capturing CO2 gases from the flue gases that result from the combustion of the fossil fuels. It furthermore comprises a CO2 gas processing unit (GPU) for the compression and cooling of the captured CO2. A cooling circuit ( 24 ) of the gas processing unit (GPU) forms a closed loop that includes a heat exchanger ( 25 ) for the heating of brine, where this heat exchanger ( 25 ) is part of a water treatment system having a multi-stage flash distiller (MSF). In the closed loop ( 24 ) low-temperature waste heat from the CO2 gas processing unit (GPU) is utilized for the water treatment system. The overall power plant energy efficiency is thereby increased.

1 . A power plant for the generation of electrical energy comprising one or more steam turbines ( 2 ,  3 ,  4 ) or one or more gas turbines ( 13 ) or both, which are driven by fossil fuels, the power plant further comprising a CO 2 capture system for capturing CO 2  gases from the flue gases that result from the combustion of the fossil fuels and a gas processing unit (GPU) for processing the captured CO 2  having one or more compressors ( 30 ) and one or more coolers ( 23 ) for the compression and cooling of the CO 2  gas, the power plant comprising:
 a water treatment system having a multi-stage flash distiller (MSF) in fluid communication with a first heat exchanger ( 25 ) for the heating of brine flowing through the water treatment system, wherein the first heat exchanger ( 25 ) is configured and arranged for a heat exchanging medium to pass therethrough, wherein the heat exchanging medium results from one or more coolers ( 23 ) adapted for the cooling of the CO 2 gas and wherein the heat exchanging medium is directed back to the one or more coolers ( 23 ) for the cooling of the CO 2  gas after exiting the first heat exchanger ( 25 ).   
     
     
         2 . The power plant according to  claim 1 , further comprising a second heat exchanger ( 45 ), wherein the second heat exchanger ( 45 ) is configured and arranged for preheating raw feedwater prior to its entry into the MSF distiller and for a heat exchanging medium, which results from the one or more coolers ( 23 ) for the cooling of the CO 2  gas and from the first heat exchanger ( 25 ) of the multi-stage flash distiller (MSF), wherein this heat exchanging medium is directed back to the one or more coolers ( 23 ) for the cooling of the CO 2  gas after exiting the first heat exchanger ( 25 ). 
     
     
         3 . The power plant according to  claim 1 , wherein the heat exchanging medium resulting from the coolers ( 23 ) for the cooling of the CO 2  gas has a temperature less than 90° C. at its entry into the first heat exchanger ( 25 ). 
     
     
         4 . The power plant according to  claim 1 , wherein the multi-stage flash distiller (MSF) is configured and arranged to separate raw feedwater to be treated into a distillate flow and a brine flow. 
     
     
         5 . The power plant according to  claim 1 , wherein the power plant further comprises a unit for reducing the brine flow to a solid. 
     
     
         6 . The power plant according to  claim 5 , wherein the unit is a zero-liquid discharge crystallizer ( 60 ). 
     
     
         7 . The power plant according to  claim 2 , wherein the raw feedwater flow directed to the multi-stage flash distiller (MSF) is waste water from the power plant, sea water, and/or raw water from an external source. 
     
     
         8 . The power plant according to  claim 1 , further comprising a deaereator is provided in a conduit ( 40 ,  53 ,  47 ) for the raw feedwater upstream of the multi-stage flash distiller (MSF) evaporator. 
     
     
         9 . The power plant according to  claim 1 , further comprising a conduit ( 28 ) configured to provide low-pressure steam to the first heat exchanger ( 25 ). 
     
     
         10 . The power plant according to  claim 2 , wherein the heat exchanging medium flowing through the first heat exchanger ( 25 ) or the first and the second heat exchangers ( 25 ,  45 ) is water, oil, or vapor. 
     
     
         11 . A method of operating the power plant of  claim 2 , wherein a ratio of a saline concentration of the brine blowdown exiting from the multistage distiller (MSF) to a saline concentration of the raw feedwater entering the multi-stage distiller (MSF) is in the range from 10 to 100. 
     
     
         12 . The method of operating a power plant of  claim 2 , wherein a ratio of a saline concentration of the brine blowdown to a saline concentration of the raw feedwater to be treated is 50. 
     
     
         13 . The method of operating a power plant of  claim 1 , wherein a temperature of the brine at its entry into a first chamber ( 31 ) of the multi-stage distiller (MSF) after being heating in the first heat exchanger ( 25 ) is in the range from 50 to 70° C., and a heat source temperature of the heat exchanging medium flowing through the first heat exchanger ( 25 ) or through the first and second heat exchangers ( 25 ,  45 ) is 70° C. at its entry into the first heat exchanger ( 25 ) and 45° C. at its exit from the first heat exchanger ( 25 ) or second heat exchanger ( 45 ), and a temperature difference between the temperature of the brine entering the multi-stage distiller (MSF) and the temperature of the brine leaving the multi-stage  5  distiller (MSF) is in the range from 25 to 45° C. 
     
     
         14 . The method according to  claim 13 , wherein the temperature of the brine at its entry into the first chamber ( 31 ) of the multistage distiller (MSF) after being heating in the first heat exchanger ( 25 ) is 60° C., and the heat source temperature of the heat exchanging medium flowing through the first heat exchanger ( 25 ) or through the first and second heat exchangers ( 25 ,  45 ) is 70° C. at its entry into the first heat exchanger ( 25 ) and 45° C. at its exit from 5 the first heat exchanger ( 25 ) or second heat exchanger ( 45 ), and the temperature difference between the temperature of the brine entering the multi-stage distiller (MSF) and the temperature of the brine leaving the multi-stage distiller (MSF) is 35° C.