# US 5,341,577 A · Drying method of and drying apparatus for powder and granular material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,341,577 A - Document ID: US5341577A - Status: Granted - Kind: A - Application number: 08/094,437 - Filed: 1993-07-21 - Granted: 1994-08-30 - Earliest claimed: 1992-07-21 - Assignees: Mitsubishi Kasei Corporation - Inventors: Iori Hashimoto; Motoki Numata; Jun Nishizawa; Tomiyuki Kamada - Web page: https://patentgrep.com/patent/US5341577A ## CPC - F26B 11/028: {Arrangements for the supply or exhaust of gaseous drying medium for direct heat transfer, e.g. perforated tubes, annular passages, burner arrangements, dust separation, combined direct and indirect heating} - F26B 3/00: Drying solid materials or objects by processes involving the application of heat (in specific machines or apparatus F26B9/00 - F26B19/00) - F26B 23/02: using combustion heating ({F26B3/305, F26B13/186, F26B21/001, } F26B23/10 take precedence) - F26B 25/22: Controlling the drying process in dependence on liquid content of solid materials or objects - F26B: DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM (drying devices for combines A01D41/133; racks for drying fruit or vegetables A01F25/12; drying foodstuffs A23; drying hair A45D20/00; body-drying implements A47K10/00; drying household articles A47L; drying gases or vapours B01D; chemical or physical processes for dewatering or like separating liquids from solids B01D43/00; centrifugal apparatus B04; drying ceramics C04B33/30; drying yarns or fabrics in association with some other form of treatment D06C; drying frames for laundry without heating or positive air circulation, domestic laundry-or spin-driers, wringing or hot pressing laundry D06F; furnaces, kilns, ovens F27) ## Abstract Carbon black is introduced into a granulating machine 3 through an inlet 1 and water is introduced into the same through an inlet 2 to prepare granulated carbon black, which is fed to a cylindrical rotary type dryer 5 through a line 4 and is dried. A product of carbon black is discharged through a line 6. Temperature in the dryer 5 is measured by a plurality of thermometers 10. A combustion control device performs the arithmetical processing of temperature data to obtain the initial point at which the state of the carbon black is changed from the constant rate of drying to the falling rate of drying. The control device controls each flow rate of fuel supplied from each line 7 or 8 to burners 9 for the front and rear half portions of the dryer by using the critical point and the temperature of the carbon black at the outlet of the dryer, whereby a temperature profile for the carbon black in the dryer 5 can be made stable for a long time. ## Claims ### Claim 1 In a drying method of powder and granular material which dries powder and granular material within a time from the introducing of the powder and granular from an end of a dryer having heat sources in plurally divided sections to the discharging of the powder and granular from the other end of the dryer, the drying method being characterized in that the temperature of the powder and granular material in the dryer is measured; a critical point at which a state of drying of the powder and granular material is changed from a constant rate of drying to a falling rate of drying is estimated by calculation on the basis of a result of the temperature measurement and the temperature of the powder and granular material at the outlet of the dryer; and the temperature of the powder and granular material at the outlet of the dryer and the critical point are controlled by controlling independently the quantity of heat of the plural heat sources on the basis of a result of the estimation of the critical point concerning the state of drying of the powder and granular material. ### Claim 2 (depends on 1) The drying method of powder and drying material according to claim 1, wherein the critical point is estimated by calculating the intersection of an approximate expression: t=K-B.times.e.times.p (-x/T), and a temperature of 100.degree. C. where t denotes temperature, x denotes a distance between a leading temperature measuring device at the inlet of the dryer, in a falling rate drying region and another temperature measuring device in the falling rate drying region, and K, B and T are respectively coefficient. ### Claim 3 (depends on 1) The drying method of powder and granular material according to claim 1, wherein the control of the temperature of the powder and granular material at the outlet of the dryer and the critical point is conducted by using at least one among a step response model, an impulse response model and an ARX model. ### Claim 4 (depends on 1) The drying method of powder and granular material according to claim 1, wherein the control of the temperature of the powder and granular material at the outlet of the dryer and the critical point is conducted by using only a step response model. ### Claim 5 (depends on 2) The drying method of powder and granular material according to claim 2, wherein the falling rate drying region has three or more numbers of temperature measuring devices at separate positions. ### Claim 6 (depends on 1) The drying method of powder and granular material according to claim 1, wherein oxidization characteristics of the powder and granular material are largely changed in the falling rate drying region. ### Claim 7 (depends on 6) The drying method of powder and granular material according to claim 6, wherein the powder and granular material is carbon black. ### Claim 8 In a drying apparatus for drying powder and granular material by heat sources located in plurally divided sections in a dryer having a powder and granular material feeding path which connects an inlet for the powder and granular material at its one end to an outlet at its other end, the drying apparatus being characterized by comprising: temperature measuring devices for measuring the temperature of the powder and granular material at a plurality of locations in the powder and granular material feeding path in the dryer; a drying-state-critical-point estimation means for estimating by calculation the critical point at which the drying state of the powder and granular material changes from a constant rate of drying to a falling rate of drying, on the basis of a result of the measurement of the powder and granular material by the temperature measuring devices; and a combustion control device means which operates independently the quantity of heat from the plurality of heat sources on the basis of a result of the estimation by the drying-state-critical-point estimation means and the temperature of the powder and granular material at the outlet of the dryer, whereby the temperature of the powder and granular material at the outlet of the dryer and the critical point of the drying state are controlled. ### Claim 9 (depends on 8) The drying apparatus for powder and drying material according to claim 8, wherein the critical point is estimated by calculating the intersection of an approximate expression: t=K-B.times.e.times.p (-x/T), and a temperature of 100.degree. C. where t denotes temperature, x denotes a distance between a leading temperature measuring device at the inlet of the dryer, in a falling rate drying region and another temperature measuring device in the falling rate drying region, and K, B and T are respectively coefficients. ### Claim 10 (depends on 8) The drying apparatus for powder and granular material according to claim 8, wherein the controlling by the combustion control device means of the temperature of the powder and granular material at the outlet of the dryer and the critical point is conducted by using at least one among a step response model, an impulse response model and an ARX model. ### Claim 11 (depends on 8) The drying apparatus for powder and granular material according to claim 8, wherein the controlling by the combustion control device means of the temperature of the powder and granular material at the outlet of the dryer and the critical point is conducted by using only a step response model. ### Claim 12 (depends on 9) The drying apparatus for powder and granular material according to claim 9, wherein the falling rate drying region has three or more numbers of temperature measuring devices at separate positions. ### Claim 13 (depends on 8) The drying apparatus for powder and granular material according to claim 8, wherein oxidization characteristics of the powder and granular material are largely changed in the falling rate drying region. ### Claim 14 (depends on 13) The drying apparatus for powder and granular material according to claim 13, wherein the powder and granular material is carbon black.