Method and assembly for improving the dynamic behavior of a coal-fired power plant

Abstract

The invention relates to a method for improving the dynamic behavior of a coal-fired power plant for primary and/or secondary requirements of the power grid operator with respect to the current output into the grid, wherein the power plant has a nominal output (RC) and is operated by way of firing, wherein upon an increase in the primary and/or secondary requirements of the power grid operator with respect to the current output into the grid the coal dust volume that is supplied is raised with respect to the present actual output, and wherein upon a decrease in the primary and/or secondary requirements of the power grid operator with respect to the current output into the grid the coal dust volume that is supplied is lowered with respect to the present actual output and is stored, and to an assembly for carrying out the method.

1 . A method for improving the dynamic behavior of a coal-fired power plant for primary and/or secondary requirements of the power grid operator with respect to the current output into the grid, wherein the power plant has a nominal output (RC) and is operated with a furnace comprising at least one firing box for the firing of the fuel, at least two coal grinding plants for the grinding of the fuel having a direct fuel system, wherein at least one of these coal grinding plants comprises an additional indirect firing system and the coal dust is indirectly fed to the firing box via the indirect firing system having at least one silo and apportioning organs and the further coal grinding plant(s) directly feeds the coal dust to the firing box via the direct firing system, and wherein upon an increase of the primary and/or secondary requirements of the power grid operator with respect to the current output into the grid the coal dust quantity indirectly fed in via silo and apportioning organs compared with the present actual output or compared with the coal dust quantity fed in through each of the coal grinding plant(s) is increased and in the process coal dust stocked in the silo is withdrawn and introduced into the firing box, and wherein upon a reduction of the primary and/or secondary requirements of the power grid operator with respect to the current output into the grid the coal dust quantity indirectly fed in via silo and apportioning organs is reduced compared with the present actual output or compared with the coal dust quantity fed in through each of the coal grinding plant(s) is reduced and in the process coal dust excessively produced by the grinding plant stored in the silo. 
     
     
         2 . The method as claimed in  claim 1 , characterized in that the silo has a storage volume (V Sp ) and in normal operation of the indirect firing system with regard to volume is filled to about half with coal dust for stocking and use upon an increase of the primary and/or secondary requirements of the power grid operator with respect to the power output into the grid and the remaining storage volume is used for receiving and storing the excess produced coal dust upon reduction of the primary and/or secondary requirements of the power grid operator with respect to the current output into the grid. 
     
     
         3 . The method as claimed in  claim 1 , characterized in that the increase or reduction of the indirectly fed-in coal dust quantity is effected through controlled increase or reduction of the throughput rate of the apportioning organs. 
     
     
         4 . The method as claimed in  claim 1 , characterized in that upon an increase or a reduction of the indirectly fed-in coal dust quantity the volumetric flow of the conveying gas blower is increased or reduced in a controlled manner. 
     
     
         5 . The method as claimed in  claim 3 , characterized in that the increase or the reduction of the throughput rate of the apportioning organs and/or the increase or reduction of the volumetric flow of the conveying gas blower is brought about by the block output control of the coal-fired power plant influenced by the requirements of the power grid. 
     
     
         6 . The method as claimed in  claim 1 , characterized in that the primary requirement is triggered through a remote-controlled signal. 
     
     
         7 . The method as claimed in  claim 1 , characterized in that the secondary requirement is triggered through a remote-controlled signal. 
     
     
         8 . The method as claimed in  claim 1 , characterized in that the secondary requirement is triggered through written or oral instruction to the operating personnel of the power plant. 
     
     
         9 . An assembly for improving the dynamic behavior of a coal-fired power plant for primary and/or secondary requirements of the power grid operator with respect to the current output into the grid, wherein the power plant has a nominal output (RC) and is designed with a furnace ( 1 ) which substantially comprises at least one firing box for the firing of the fuel, at least two coal grinding plants ( 2 . 1 ,  2 . 2 ) for the grinding of the fuel comprising a direct firing system, wherein at least one of these coal grinding plants ( 2 . 1 ,  2 . 2 ) comprises an additional indirect firing system and the coal dust can be indirectly fed to the firing box via the indirect firing system having at least one silo ( 5 ) and apportioning organs ( 10 ) and with the further coal grinding plant(s) ( 2 . 1 ,  2 . 2 ) the firing box can be directly fed with coal dust via the direct firing system,
 and wherein upon an increase of the primary and/or secondary requirements of the power grid operator with respect to the current output into the grid the coal dust quantity that can be indirectly fed in via silo ( 5 ) and apportioning organs ( 10 ) compared to the present actual output or compared to the coal dust quantity that can be fed in by the coal grinding plant(s) ( 2 . 1 ,  2 . 2 ) in each case can be increased and in the process coal dust stocked in the silo ( 5 ) can be withdrawn and introduced into the firing box   and wherein upon a reduction of the primary and/or secondary requirements of the power grid operator with respect to the current output into the grid the coal dust quantity that can be indirectly fed in via silo ( 5 ) and apportioning organs ( 10 ) compared with the present actual output or compared with the coal dust quantity that can be fed in through the coal grinding plant(s) ( 2 . 1 ,  2 . 2 ) in each case can be reduced and in the process excess coal dust produced by the grinding plant ( 2 . 1 ,  2 . 2 ) can be stored in the silo ( 5 ).