Method of distributing and transporting powdered or granular material

• US 4,529,336 A
• Filed: 04/06/1983
• Issued: 07/16/1985
• Est. Priority Date: 12/27/1982
• Status: Expired due to Term

• Current Assignee: Denka Consultant & Engineering Co. Ltd. (Denka Company Limited), Kawasaki Steel Corporation (JFE Holdings Incorporated)
• Original Assignee: Denka Consultant & Engineering Co. Ltd. (Denka Company Limited), Kawasaki Steel Corporation (JFE Holdings Incorporated)
• Inventors: Masuda, Yoshiaki, Iwamura, Tadaaki, Fujii, Shuzo, Takabe, Ryoji, Moriyama, Takashi, Yanagihara, Yasuo, Oishi, Hideo, Yasuno, Motozo, Shinozaki, Yoshinobu, Marushima, Hironari, Tagawa, Yoshiteru, Achiba, Keiichi
• Primary Examiner(s): Nase, Jeffrey V.
• Assistant Examiner(s): Williams, L. E.
• Application Number:
  US06/482,638
• Time in Patent Office: 832 Days
• Field of Search: 406/123, 406/124, 406/93-95, 406/24, 406/25, 406/14, 222/1
• US Class Current: 406/14
• CPC Class Codes: B65G 53/66 Use of indicator or control devices, e.g. for controlling gas pressure, for controlling proportions of material and gas, for indicating or preventing jamming of material controlling the flow of coal firing systems C21B5/003
• CPC Class Codes: C21B 5/003 Injection of pulverulent coal

Abstract

A method of distributing powdered or granular material to a plurality of feeding ends in a system having a pressurizing tank for pressurizing and fluidizing a powdered or granular material, a plurality of transportation pipes having one ends constituting discharge nozzles opening above a fluidized bed in the tank and the other ends connected to different feeding ends so as to introduce the material to the feeding ends, and a plurality of booster gas supply pipes for supplying respective transportation pipes with a booster gas. The internal pressure of the tank is controlled by a controller provided with a set valve in accordance with the mean value of the terminal pressures at the feeding ends, the mean value of predetermined set flow rates of the booster gas in the booster gas supplying pipes, and the mean value of predetermined set rates of transportation of material to the feeding ends.

Claims

1. In a system having a pressurizing tank for pressurizing and fluidizing a powdered or granular material, a plurality of transportation pipes having one ends constituting discharge nozzles opening above a fluidized bed in said tank and the other ends connected to different feeding ends so as to introduce said material to said feeding ends, and a plurality of booster gas supply pipes for supplying respective transportation pipes with a booster gas,

a method of directly distributing and transporting said material to said feeding ends comprising the steps of:

determining a set value of an internal pressure of the pressurizing tank in accordance with a mean value of terminal pressures at said feeding ends, a mean value of predetermined set flow rates of said booster gas in said booster gas supplying pipes and a mean value of predetermined set flow rates of said material to said feeding ends, and providing a signal representing said set value of the internal pressure;

detecting an actual internal pressure of the pressurizing tank and providing a signal representing said actual internal pressure;

comparing said signal representing said set value of the internal pressure with said signal representing said actual internal pressure and providing a control signal; and

controlling the internal pressure of the pressurizing tank in accordance with said control signal.

2. A method of distributing and transporting powdered or granular material according to claim 1, wherein the set value of the internal pressure of said pressurizing tank is determined in accordance with the following formula:

##EQU1## where, P₂ represents the mean value of the terminal pressures at said feeding ends, Q_B represents the mean value of the predetermined set flow rates of said booster gas to said transportation pipes, dw/dt represents the mean value of the predetermined set rates of transportation of said material to said feeding ends, and A,B,C,D and E represent positive constants.

3. In a system having a pressurizing tank having a weighing device and adapted for pressurizing and fluidizing a powdered or granular material, a plurality of transportation pipes having one ends constituting discharge nozzles opening above a fluidized bed in said tank and the other ends connected to different feeding ends so as to introduce said material to said feeding ends, and a plurality of booster gas supply pipes for supplying respective transportation pipes with a booster gas,

a method of directly distributing and transporting said material to said feeding terminals comprising the steps of:

calculating the sum of predetermined set flow rates of said material to said feeding ends, and providing a signal representing said sum as a set value;

calculating actual discharging rate of said material from said pressurizing tank through calculating a rate of change of weight of said pressurizing tank by said weighing device, and providing a signal representing the actual discharging rate;

comparing said signal representing said sum with said signal representing the actual discharging rate and providing a comparison signal;

determining a set value of an internal pressure of the pressurizing tank in accordance with said comparison signal and providing a signal representing said set value of the internal pressure;

detecting an actual internal pressure of the pressurizing tank and providing a signal representing said actual internal pressure;

comparing said signal representing said set value of the internal pressure with said signal representing said actual internal pressure and providing a control signal; and

controlling the internal pressure of the pressurizing tank in accordance with said control signal.

4. In a system having a pressurizing tank provided with a weighing device and adapted for pressurizing and fluidizing a powdered or granular material, a plurality of transportation pipes having one ends constituting discharge nozzles opening above a fluidized bed in said tank and the other ends connected to different feeding ends so as to introduce said material to said feeding ends, and a plurality of booster gas supply pipes for supplying respective transportation pipes with a booster gas,

a method for directly distributing and transporting said material to said feeding ends comprising the steps of:

determining set values of pressure differentials across said discharge nozzles of said transportation pipes in accordance with predetermined set flow rates of said material to said feeding ends;

delivering signals representing said set values of said pressure differentials to pressure differential controllers together with signals representing actually measured pressure differentials across said discharge nozzles;

determining, in accordance with output signals from said pressure differential controllers, set values for booster gas flow rate controllers for controlling flow rates of said booster gas to the respective transportation pipes; and

controlling a discharging rate of the material in each of the transportation pipes by individually controlling a flow rate of said booster gas in accordance with each of said set values.

5. A method of distributing and transporting powdered or granular material according to claim 4, wherein the set value Δ

P_N of pressure differential across each said discharge nozzle is determined in accordance with the following formula;

space="preserve" listing-type="equation">dw/dt=FΔ

P.sub.N.sup.2 +G

where, dw/dt represents the predetermined set flow rate of said material to corresponding feeding ends, while F and G represent positive constants.

7. A method of distributing and transporting powdered or granular material according to claim 4, wherein the set values for said booster gas flow rate controller are determined in accordance with output signals selectively delivered from said pressure differential controllers and material transportation rate controllers which receive a signal representing actually measured flow rate of said material.

6. In a system having a pressurizing tank provided with a weighing device and adapted for pressurizing and fluidizing a powdered or granular material, a plurality of transportation pipes having one ends constituting discharge nozzles opening above a fluidized bed in said tank and the other ends connected to different feeding ends so as to introduce said material to said feeding ends, and a plurality of booster gas supply pipes for supplying respective transportation pipes with a booster gas,

a method of directly distributing and transporting said material to said feeding ends comprising the steps of:

determining a first set value of an internal pressure of said pressurizing tank in accordance with a mean value of the terminal pressures at said feeding ends, a mean value of predetermined set flow rates of said booster gas in said booster gas supplying pipes, and a mean value of predetermined set flow rates of said material to said feeding ends;

calculating a sum of the predetermined set flow rates of said material to said feeding ends, and providing a signal representing said sum;

calculating actual discharging rate of said material from said pressurizing tank through calculating a rate of change of weight of said pressurizing tank by said weighing device, and providing a signal representing the actual discharging rate;

determining a second set value of the internal pressure of said tank in accordance with a comparison signal being provided by comparing said signal representing said sum of the predetermined set flow rates of the material with said signal representing the actual discharging rate of said material;

correcting said first set value of the internal pressure of said pressurizing tank in accordance with said second set value and determing a corrected set value;

detecting an actual internal pressure of the pressurizing tank and providing a signal representing said actual internal pressure;

controlling the internal pressure of the pressurizing tank in accordance with a control signal being provided by comparing said corrected set value and said actual internal pressure;

determining set values of pressure differentials across said discharging nozzles of said transportation pipes in accordance with said predetermined set flow rates of said material to the respective feeding ends;

delivering signals representing said set values of said pressure differentials to pressure differential controllers together with signals representing actually measured pressure differentials across said respective discharge nozzles;

determining, in accordance with output signals from said pressure differential controllers, set values for booster gas flow rate controllers for controlling flow rates of said booster gas to the respective transportation pipes; and

controlling a discharging rate of the material in each of the transportation pipes by individually controlling a flow rate of said booster gas in accordance with each of said booster gas flow rate controllers.

8. A method of distributing and transporting powdered or granular material according to claim 6, wherein the set values for said booster gas flow rate controller are determined in accordance with output signals selectively delivered from said pressure differential controllers and material transportation rate controllers which receive a signal representing actually measured flow rate of said material.