Method and system for adjusting the flow rate of charge material in a charging process of a shaft furnace

Patent metadata

Field	Value
Publication number	US-9031704-B2
Application number	US-201013148953-A
Country	US
Kind code	B2
Filing date	Feb 11, 2010
Priority date	Feb 11, 2009
Publication date	May 12, 2015
Grant date	May 12, 2015

Abstract

In a charging process of a shaft furnace, in particular of a blast furnace, batches of charge material are typically discharged in cyclical sequence into the furnace from a top hopper using a flow control valve. A method and system is proposed for adjusting the flow rate of charge material in such a process. Pre-determined valve characteristics for certain types of material are provided, each indicating the relation between flow rate and valve setting for one type of material. According to the invention, a specific valve characteristic is stored for each batch of charge material, each specific valve characteristic being bijectively associated to one batch and indicating the relation between flow rate and valve setting of the flow control valve specifically for the associated batch. In relation to discharging a given batch of the sequence the invention proposes: using the stored specific valve characteristic associated to the given batch for determining a requested valve setting corresponding to a flow rate setpoint and using the requested valve setting to operate the flow control valve; determining an actual average flow rate for the discharge of the given batch; correcting the stored specific valve characteristic associated to the given batch in case of a stipulated deviation between the flow rate setpoint and the actual average flow rate.

First claim

The invention claimed is:

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:
using the stored specific valve characteristic associated to said given batch for determining a requested valve setting corresponding to a flow rate setpoint and using said requested valve setting to operate said flow control valve;
determining an actual average flow rate for the discharge of said given batch;
correcting and updating the stored specific valve characteristic associated to said given batch in case there is a deviation between said flow rate setpoint and said actual average flow rate that exceeds a set minimal deviation;

so as to reduce flow rate deviation of the stored specific valve characteristic associated to said given batch at future uses of said recipe.

2. The method according to claim 1 , wherein each specific valve characteristic is represented by at least a sequence of valve setting values, each valve setting value bijectively corresponding to one flow rate value, and wherein correcting the stored specific valve characteristic associated to a given batch comprises applying a respective correction term to each valve setting value of said sequence.

3. The method according to claim 2 , wherein said respective correction term for a given valve setting value is determined as the result of a function which increases with the difference between said flow rate setpoint and said actual average flow rate and which decreases with the distance in terms of sequence index between said given valve setting value and the valve setting value approximating or equal to said requested valve setting.

4. The method according to claim 2 , further comprising:
ensuring that said sequence of valve setting values is strictly monotonically increasing by incrementing any valve setting value that is less than or equal to the valve setting value that precedes in sequence.

5. The method according to claim 1 , a stipulated deviation being a deviation comprised in the range from a minimum tolerance factor multiplied by the flow rate setpoint to a maximum tolerance factor multiplied by the flow rate setpoint.

6. The method according to claim 1 , comprising
for discharging a given batch from said top hopper:
using said requested valve setting to operate said flow control valve at a control valve aperture that is fixed during discharging said given batch.

7. The method according to claim 1 , wherein said pre-determined valve characteristics are chosen in accordance with a predominant type of material contained in the associated batch.

8. System for adjusting the flow rate of charge material in a charging installation for a shaft furnace, said installation comprising a top hopper for storing batches of a charging-cycle, the charging-cycle being associated to a recipe for control of a 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, and a flow control valve associated to said hopper for controlling the flow rate of charge material into the furnace, said system comprising:
a data storage storing pre-determined valve characteristics, which represent a curve plotting flow rate against valve setting, 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;
a data memory 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
a programmable computing device programmed to execute the following at each discharge of a given batch of said charging-cycle associated to said recipe from said top hopper:
use the stored specific valve characteristic associated to said given batch for determining a requested valve setting corresponding to a flow rate setpoint and using said requested valve setting to operate said flow control valve;
determine an actual average flow rate for the discharge of said given batch;
correct and update the stored specific valve characteristic associated to said given batch in case there is a deviation between said flow rate setpoint and said actual average flow rate that exceeds a set minimal deviation;

so as to reduce flow rate deviation of the stored specific valve characteristic associated to said given batch at future uses of said recipe.

9. The system according to claim 8 , wherein each specific valve characteristic is represented in said data memory by at least a sequence of valve setting values, each valve setting value bijectively corresponding to one flow rate value, and wherein said programmable computing device is programmed to correct the stored specific valve characteristic associated to a given batch by applying a respective correction term to each valve setting value of said sequence.

10. The system according to claim 9 , wherein said programmable computing device is programmed to determine said respective correction term for a given valve setting value as the result of a function which increases with the difference between said flow rate setpoint and said actual average flow rate and which decreases with the distance in terms of sequence index between said given valve setting value and the valve setting value approximating or equal to said requested valve setting.

11. The system according to claim 9 , wherein said programmable computing device is programmed to ensure that said sequence of valve setting values is strictly monotonically increasing by incrementing any valve setting value that is less than or equal to the valve setting value that precedes in sequence.

12. The system according to claim 8 , a stipulated deviation being a deviation comprised in the range from a minimum tolerance factor multiplied by

Assignees

• Tockert Paul
• Breden Emile
• Lonardi Emile
• Meyer Damien
• Wurth Paul Sa

Inventors

• Tockert Paul
• Breden Emile
• Lonardi Emile
• Meyer Damien

Classifications

• C21B7/24

  Test rods or other checking devices · CPC title

• F27D19/00

  Arrangements of controlling devices · CPC title

• F27D2003/105

  using shutters · CPC title

• F27D2019/0087

  Automatisation of the whole plant or activity · CPC title

• F27B1/28

  Arrangements of monitoring devices, of indicators, of alarm devices · CPC title