System and method for optimising combustion in pulverised solid fuel boilers, and boiler including such a system

Abstract

The system comprises a boiler ( 1 ), main burner groups ( 2 F, 2 E, 2 D, 2 C) located on different levels or zones through which pulverized solid fuel is injected into the boiler ( 1 ) and main mills ( 3 F, 3 E, 3 D, 3 C) for solid fuel, where each of them is connected to one of the main burner groups ( 2 F, 2 E, 2 D, 2 C) to which a flow of solid fuel is directed. As a complement, it incorporates a substitution mill ( 3 B) intended to operate only on the main burner group ( 2 F, 2 E, 2 D, 2 C) whose main associated mill ( 3 F, 3 E, 3 D, 3 C) has stopped, as well as a support mill ( 3 A) which operates constantly and directs an additional flow of solid fuel towards the main burner group or groups ( 2 F, 2 E, 2 D, 2 C) selected, supplementing the flow of solid fuel provided by the main mills ( 3 F, 3 E, 3 D, 3 C).

1 - 12 . (canceled) 
     
     
         13 . A combustion system of pulverized solid fuel boilers comprising:
 groups of main burners located on different levels or areas, through which pulverized solid fuel is injected into the boiler,   main mills for solid fuel, where each of them is connected to each of the main burner groups to which they send a flow of solid fuel, wherein it additionally comprises:   a substitution mill intended to operate only on the main burner group whose associated main mill has stopped,   a group of distributors, whose number of elements coincides with the number of burners in each group, each of which connects the substitution mill in parallel with a burner from each group of main burners, with flow deflectors and valves in between that, depending on their position, direct the flow from the substitution mill to the main burners group whose main mill has stopped,   a support mill that operates constantly and directs an additional flow of solid fuel to the main burner group or groups selected, supplementing the flow of solid fuel provided by the main mills,   a group of flow splitters, whose number of elements coincides with the number of burners in each group, each of which connects the support mill in parallel with a burner from each group of main burners, with flow deflectors in between that, depending on their position, direct the flow from the support mill to the burners they are connected to, depending on the distribution required, and   joining ducts between the distributors and the flow splitters that incorporate a valve that permits communication to be established between the distributors and the flow splitters so that the substitution mill can carry out the functions of the support mill   
     
     
         14 . The combustion system of pulverized solid fuel boilers of  claim 13  wherein the valves are guillotine type valves. 
     
     
         15 . The combustion system of pulverized solid fuel boilers of  claim 13  wherein it additionally comprises a first group of auxiliary burners, located a level above the main burner groups, that are connected to the substitution mill and the distributors. 
     
     
         16 . The combustion system of pulverized solid fuel boilers of  claim 15  wherein it comprises a first group of 3-way connections, whose number of elements coincides with the number of burners making up each group, that establish the connection between the first group of auxiliary burners, the substitution mill and the distributors. 
     
     
         17 . The combustion system of pulverized solid fuel boilers of  claim 16  wherein the first group of 3-way connections comprises a first two-position deflector that minimises pressure drop due to the direction change. 
     
     
         18 . The combustion system of pulverized solid fuel boilers of  claim 13  wherein it additionally comprises a second group of auxiliary burners, located a level above the main burner groups, that are connected to the support mill and the flow splitters. 
     
     
         19 . The combustion system of pulverized solid fuel boilers of  claim 18 , wherein it comprises a second group of 3-way connections, whose number of elements coincides with the number of burners in each group, that establish the connection between the second group of auxiliary burners, the support mill and the flow splitters. 
     
     
         20 . The combustion system of pulverized solid fuel boilers of  claim 19 , wherein the second group of 3-way connections comprises a second two-position deflector that minimises pressure drop due the direction change. 
     
     
         21 . A pulverized solid fuel boiler comprising a combustion system of pulverized solid fuel boilers further comprising:
 groups of main burners located on different levels or areas, through which pulverized solid fuel is injected into the boiler,   main mills for solid fuel, where each of them is connected to each of the main burner groups to which they send a flow of solid fuel, wherein the combustion system additionally comprises:   a substitution mill intended to operate only on the main burner group whose associated main mill has stopped,   a group of distributors, whose number of elements coincides with the number of burners in each group, each of which connects the substitution mill in parallel with a burner from each group of main burners, with flow deflectors and valves in between that, depending on their position, direct the flow from the substitution mill to the main burners group whose main mill has stopped,   a support mill that operates constantly and directs an additional flow of solid fuel to the main burner group or groups selected, supplementing the flow of solid fuel provided by the main mills,   a group of flow splitters, whose number of elements coincides with the number of burners in each group, each of which connects the support mill in parallel with a burner from each group of main burners, with flow deflectors in between that, depending on their position, direct the flow from the support mill to the burners they are connected to, depending on the distribution required, and   joining ducts between the distributors and the flow splitters that incorporate a valve that permits communication to be established between the distributors and the flow splitters so that the substitution mill can carry out the functions of the support mill   
     
     
         22 . A process to optimise combustion of pulverized solid fuel boilers of system of  claim 13 , wherein the process comprises the stages of:
 selecting a differential injection pattern among the different groups of main burners,   selecting the main mills that will supply the main burner groups depending on the load requested from the boiler,   adjusting the flow deflectors of the flow splitters that distribute the flow from the support mill among the main burner groups located at different levels, to establish differential provisions between different levels.   
     
     
         23 . The process for optimising combustion of pulverized solid fuel boilers of  claim 22 , wherein it comprises the stage of activating the substitution mill if a main mill stops and adjusting the deflectors to direct the flow towards the specific group among the main burner groups whose main corresponding mill has stopped.