Patent ID: 9031704
Filing Date: 2015-05-12
Classification: C21B,F27B,F27D

Abstract:
1. A method of adjusting a flow rate of charge material in a charging process of a shaft furnace, wherein a charging-cycle is formed of a succession of batches that are discharged into said furnace from a top hopper using a flow control valve associated to said top hopper for controlling the flow rate of charge material, the charging-cycle being associated to a recipe for control of said charging process, each batch representing a quantity of charge material that is stored intermediately in said top hopper in order to be discharged into the furnace; pre-determined valve characteristics that represent a curve plotting flow rate against valve setting are provided for certain types of material, each pre-determined valve characteristic indicating the relation between flow rate and valve setting of said flow control valve for one type of material; said method comprising: storing a specific valve characteristic that represents a curve plotting flow rate against valve setting for each batch of said charging-cycle associated to said recipe respectively, each specific valve characteristic being bijectively associated to one batch of said charging-cycle associated to said recipe and indicating the relation between flow rate and valve setting of said flow control valve specifically for the associated batch, each specific valve characteristic being initialized to reflect a pre-determined valve characteristic; and at each discharge of a given batch of said charging-cycle associated to said recipe from said top hopper: so as to reduce flow rate deviation of the stored specific valve characteristic associated to said given batch at future uses of said recipe.