US3282514A - Method for controlling the amount of liquid added to heat absorbing gases - Google Patents

Method for controlling the amount of liquid added to heat absorbing gases Download PDF

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US3282514A
US3282514A US351144A US35114464A US3282514A US 3282514 A US3282514 A US 3282514A US 351144 A US351144 A US 351144A US 35114464 A US35114464 A US 35114464A US 3282514 A US3282514 A US 3282514A
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gas
amount
water
temperature
gases
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US351144A
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Putz Rudolf
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GEA Group AG
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Metallgesellschaft AG
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C21/00—Disintegrating plant with or without drying of the material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C19/00—Other disintegrating devices or methods
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/01—Pretreatment of the gases prior to electrostatic precipitation
    • B03C3/014—Addition of water; Heat exchange, e.g. by condensation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/06—Controlling, e.g. regulating, parameters of gas supply
    • F26B21/08—Humidity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
    • F26B25/005—Treatment of dryer exhaust gases
    • F26B25/007—Dust filtering; Exhaust dust filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28C—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA COME INTO DIRECT CONTACT WITHOUT CHEMICAL INTERACTION
    • F28C3/00—Other direct-contact heat-exchange apparatus
    • F28C3/06—Other direct-contact heat-exchange apparatus the heat-exchange media being a liquid and a gas or vapour
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D7/00—Control of flow
    • G05D7/06—Control of flow characterised by the use of electric means
    • G05D7/0605—Control of flow characterised by the use of electric means specially adapted for solid materials

Definitions

  • Jnremor- Kaila (7L 7241f United States Patent 3,282,514 METHOD FOR CONTROLLING THE AMOUNT OF LIQUID ADDED TO HEAT ABSORBING GASES Rudolf Putz, Frankfurt am Main, Germany, assignor to Metalitician Aktiengesellschaft, Frankfurt am Main, Germany Filed Mar. 11, 1964, Ser. No. 351,144 Claims priority, application Germany, Mar. 12, 1963,
  • This invention relates to a method of controlling the amount of liquid added to a gas used to absorb heat, and in particular, to a gas used to absorb heat generated during a grinding of a material.
  • a liquid such as water
  • the amount of liquid added for absorbing heat generated during grinding has been less than that required to saturate the gases so that the gases are able to take up moisture for the purpose of drying a material when occasion arises.
  • the gases which have been used in the grinding mill are cleaned in dust separators which follow those grinding mills and which are preferably electrostatic dust precipitators. These electrostatic precipitators react strongly to changes in temperature and dew point of the dust-laden gases, and consequently, the amount of dust removed from the gases varies considerably.
  • the object of this invention is to produce a method for controlling the amount of liquid added to grinding mills followed by an electrostatic or mechanical dust precipitator.
  • the water is added for the purpose of absorbing 3,282,514 Patented Nov. 1, 1956 ice heat generated by the grinding of the material, so as to humidity the gas at a value most favorable for operation of the grinding mill as well as the separator.
  • the amount of moisture added to the gas is dependent upon and controlled by the temperature difference between the temperature and the dew point of the heated waste gas.
  • a further feature of the invention lies in that the gas temperature and the gas dew point temperature are measured in the form of electrical energy which is led to a control element.
  • This control element if desired, actuates a valve control motor for metering the amount of water which is to be added to the gas.
  • the method of this invention consequently has the advantages of controlling the amount of added water to the waste gases in dependence upon both the temperature of the waste gas and dew point of the gas, but avoids the disadvantage of using either of those controls alone.
  • the grinding mill 1 receives through a chute 2 the raw material on conveyor belt 3.
  • the material on the belt can be pre-moistened by water issuing through spray nozzle 4.
  • An opening 5 in the grinding mill 1 provides for the entrance of hot drying gases if necessary.
  • Liquid is added to the gases by being introduced into the grinding mill through spray nozzles 6.
  • the treated material is discharged through hopper 7 while the hot dust-laden gases leave the grinding mill through opening 8.
  • Nozzles 6 are supplied with water by means of pipe lines 9 which include a control or metering valve 10.
  • the water issuing through nozzles 6 can be given an increased atomizin-g by means of air introduced through compressed air pipes 11. Hot gases passing through opening 8 are led through duct 12 to an electrostatic dust precipitator 13.
  • thermocouples 14 and 15 located in the clean gas line duct 16.
  • the clean gas is discharged into the atmosphere by means of blower 17 and chimney 18.
  • the temperature values from thermocouples 14 and 15 are passed through electrical amplifiers 14 and 15, respectively, and this current led to a control device 19.
  • thermocouples 14 and 15 are compared in device 19 and their differences per unit of time evaluated. Inasmuch as one temperature value may fluctuate widely with respect to the other, the differences in the temperature values in the form of electric pulses are sent to a time relay 20 in order to be averaged for a period of time. Then, depending upon the values in time delay relay 20, a signal is either sent to the control relay 21 for starting motor 23 by closing switch 24 or for reversing or stopping the motor by sending a pulse to control relay 22. Motor 23 will then either open valve 19 for admitting more water into mill 1 or for reducing the flow of water in accordance with the dew point required therein.
  • valve 10 is always set to a position dependent upon the difference between the temperature of the hot waste gas and the dew point of the waste gas. Should more water he required in a given period of time, then a pulse from device 19 energizes servo motor 25 to close the throttle valve 26 in duct 12 so that the gases in mill 1 can accumulate more water with a raised dew point before they are released into filter 13. Thus the flow of the gases in duct 12 is made dependent upon the difference between the temperature and dew point of the hot waste gases.
  • the improvement further comprising measuring the difference between the temperature and the dew point of the hot gas in the form of electrical energy, and then using said energy to actuate a motor 10 controlled valve in the Water supply line for the water added to said gas.
  • said separator comprising an electrostatic dust precipitator.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Disintegrating Or Milling (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Crushing And Grinding (AREA)

Description

Nov. 1, 1966 UTZ 3,282,514
R. P METHOD FOR CONTROLLING THE AMOUNT OF LIQUID ADDED TO BEAT ABSORBING GASES Filed March 11, 1964.
Jnremor- Kaila (7L 7241f United States Patent 3,282,514 METHOD FOR CONTROLLING THE AMOUNT OF LIQUID ADDED TO HEAT ABSORBING GASES Rudolf Putz, Frankfurt am Main, Germany, assignor to Metaligesellschaft Aktiengesellschaft, Frankfurt am Main, Germany Filed Mar. 11, 1964, Ser. No. 351,144 Claims priority, application Germany, Mar. 12, 1963,
4 Claims. ci. 241-17 This invention relates to a method of controlling the amount of liquid added to a gas used to absorb heat, and in particular, to a gas used to absorb heat generated during a grinding of a material.
Often a liquid, such as water, is introduced into the grinding mill for absorbing heat generated by the grinding. Also, for various reasons, it has been further found that it is desirable to moisten the material before or during grinding the same. However, the amount of liquid added for absorbing heat generated during grinding has been less than that required to saturate the gases so that the gases are able to take up moisture for the purpose of drying a material when occasion arises. The gases which have been used in the grinding mill are cleaned in dust separators which follow those grinding mills and which are preferably electrostatic dust precipitators. These electrostatic precipitators react strongly to changes in temperature and dew point of the dust-laden gases, and consequently, the amount of dust removed from the gases varies considerably.
Experience has shown that the amount of dust discharged from the separator increases many times when the difference between the temperature of the gas and the dew point of the gas exceeds a certain value. In many installations, especially cement grinding mills, water has been added to the clinkers and to the interior of these grinding mills. In addition to the advantages obtained in the grinding mill, there are better operating conditions for the electrostatic separators. However, the control of the amount of water added has been exclusively dependent upon the temperature of the dust-laden waste gas. Such a control is not responsive to the amount of moisture in the gas and therefore has only a limited use. Such a control is disadvantageous as shown by the following example:
In operating a grinding mill followed by an electrostatic separator, it was proposed to use a moisture laden gas with a dew point of 35 C. and a temperature of 60 C. In actual operation, the grinding mill operated with a gas discharge temperature of 55 C. because an easily grindable material was used. Inasmuch as the controls were such that Water would not be added until a temperature of 60 C. was reached, the apparatus was not supplied with water so that the dew point lay at approximately C. At this dew point, the electrostatic precipitator worked with such little effectiveness that the entire installation had to be shut down because of the large amount of unprecipitated dust discharged along with the waste gases from the precipitator.
Such a result suggests that it would be better to make the control of the amount of added water dependent upon the dew point of the added gas. This, however, has the disadvantage in that, when the dew point is exceeded during low gas temperatures, scaling and dust deposits are formed because of the condensation of the moisture in the dust or the ground material, and this endangers the operation of the entire apparatus.
The object of this invention is to produce a method for controlling the amount of liquid added to grinding mills followed by an electrostatic or mechanical dust precipitator. The water is added for the purpose of absorbing 3,282,514 Patented Nov. 1, 1956 ice heat generated by the grinding of the material, so as to humidity the gas at a value most favorable for operation of the grinding mill as well as the separator.
In this invention, the amount of moisture added to the gas is dependent upon and controlled by the temperature difference between the temperature and the dew point of the heated waste gas.
A further feature of the invention lies in that the gas temperature and the gas dew point temperature are measured in the form of electrical energy which is led to a control element. This control element, if desired, actuates a valve control motor for metering the amount of water which is to be added to the gas.
The method of this invention consequently has the advantages of controlling the amount of added water to the waste gases in dependence upon both the temperature of the waste gas and dew point of the gas, but avoids the disadvantage of using either of those controls alone.
The means by which the objects of the invention are obtained are described more fully with reference to the accompanying schematic drawing.
The grinding mill 1 receives through a chute 2 the raw material on conveyor belt 3. The material on the belt can be pre-moistened by water issuing through spray nozzle 4. An opening 5 in the grinding mill 1 provides for the entrance of hot drying gases if necessary. Liquid is added to the gases by being introduced into the grinding mill through spray nozzles 6. The treated material is discharged through hopper 7 while the hot dust-laden gases leave the grinding mill through opening 8. Nozzles 6 are supplied with water by means of pipe lines 9 which include a control or metering valve 10. The water issuing through nozzles 6 can be given an increased atomizin-g by means of air introduced through compressed air pipes 11. Hot gases passing through opening 8 are led through duct 12 to an electrostatic dust precipitator 13. The clean waste gas leaving precipitator 13 has its temperature and dew point measured by thermocouples 14 and 15, respectively, located in the clean gas line duct 16. The clean gas is discharged into the atmosphere by means of blower 17 and chimney 18. The temperature values from thermocouples 14 and 15 are passed through electrical amplifiers 14 and 15, respectively, and this current led to a control device 19.
The temperature values from thermocouples 14 and 15 are compared in device 19 and their differences per unit of time evaluated. Inasmuch as one temperature value may fluctuate widely with respect to the other, the differences in the temperature values in the form of electric pulses are sent to a time relay 20 in order to be averaged for a period of time. Then, depending upon the values in time delay relay 20, a signal is either sent to the control relay 21 for starting motor 23 by closing switch 24 or for reversing or stopping the motor by sending a pulse to control relay 22. Motor 23 will then either open valve 19 for admitting more water into mill 1 or for reducing the flow of water in accordance with the dew point required therein. Thus valve 10 is always set to a position dependent upon the difference between the temperature of the hot waste gas and the dew point of the waste gas. Should more water he required in a given period of time, then a pulse from device 19 energizes servo motor 25 to close the throttle valve 26 in duct 12 so that the gases in mill 1 can accumulate more water with a raised dew point before they are released into filter 13. Thus the flow of the gases in duct 12 is made dependent upon the difference between the temperature and dew point of the hot waste gases.
Having now described the means by which the objects of the invention are obtained, I claim:
1. In a method for adding water to -a grinding mill for moistening gas passing through said mill for removing dew point of the heated gas for maintaining optimum con- 5 stant dust separating conditions in the dust separator.
2. In a method as in claim 1, the improvement further comprising measuring the difference between the temperature and the dew point of the hot gas in the form of electrical energy, and then using said energy to actuate a motor 10 controlled valve in the Water supply line for the water added to said gas.
3. In a method as in claim 2, said separator comprising an electrostatic dust precipitator.
References Cited by the Examiner 4. In a method as in claim 2, said separator comprising 15 ROBERT BURNETT a Examinen a mechanical dust separator.

Claims (1)

1. IN A METHOD FOR ADDING WATER TO A GRINDING MILL FOR MOISTENING GAS PASSING THROUGH SAID MILL FOR REMOVING HEAT FROM SAID MILL, AND IN WHICH THE GAS IS THEN PASSED THROUGH A DUST SEPARATOR, THE IMPROVEMENT COMPRISING ADDING SAID WATER TO SAID GAS AT A RATE CONTROLLED BY THE TEMPERATURE DIFFERENCE BETWEEN THE TEMPERATURE AND THE DEW POINT OF THE HEATED GAS FOR MAINTAINING OPTIMUM CONSTANT DUST SEPARATING CONDITIONS IN THE DUST SEPARATOR.
US351144A 1963-03-12 1964-03-11 Method for controlling the amount of liquid added to heat absorbing gases Expired - Lifetime US3282514A (en)

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DEM56078A DE1227769B (en) 1963-03-12 1963-03-12 Process for regulating the gas condition in mills

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BE (1) BE644935A (en)
CH (1) CH421671A (en)
DE (1) DE1227769B (en)
GB (1) GB1002626A (en)
NL (1) NL6402491A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3373944A (en) * 1966-02-24 1968-03-19 Bethlehem Steel Corp Method and apparatus for controlling consistency
US3923254A (en) * 1972-12-04 1975-12-02 Smidth & Co As F L Cement mill and method of starting same
US3989482A (en) * 1971-06-11 1976-11-02 Polysius Ag Method for the removal of dust from exhaust gases
US4400184A (en) * 1979-05-18 1983-08-23 Hitachi Shipbuilding And Engineering Company Limited System for recovering pressure and sensible heat from blast furnace gas with use of dry-type dust collector
US4642127A (en) * 1980-08-28 1987-02-10 Sumitomo Metal Industries, Ltd. Method for cooling blast furnace gas in an heat recovery system

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3108968A1 (en) * 1981-03-10 1982-09-30 Metallgesellschaft Ag, 6000 Frankfurt METHOD FOR OPTIMIZING THE SEPARATION PERFORMANCE OF AN ELECTROFILTER
DE3227543C3 (en) * 1982-07-23 1994-11-24 Thyssen Industrie Devices for improving dust separation in electrostatic filters
DE19909222A1 (en) * 1999-03-03 2000-09-07 Goergens Hermann Josef Turbine rotor temperature regulating process, involving reducing temperature by evaporating fine water mist in interior of rotor
CN105806077A (en) * 2014-12-31 2016-07-27 上海泽玛克敏达机械设备有限公司 Lignite drying system
CN110614152B (en) * 2019-11-11 2024-03-26 西安科技大学 Coal sample grinding device and coal sample grinding experimental device

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1429973A (en) * 1920-04-29 1922-09-26 Charles Tagliabue Mfg Co Humidity controller
US1820734A (en) * 1929-01-09 1931-08-25 Siemens Ag Gas purifying plant
DE545426C (en) * 1929-04-20 1932-02-29 Siemens Schuckertwerke Akt Ges Device for automatic humidification, especially hot gases to be cleaned electrically
FR739811A (en) * 1931-07-09 1933-01-17 Siemens Ag Process for the preliminary treatment of gases intended to be purified electrically
US1909825A (en) * 1928-08-01 1933-05-16 Int Precipitation Co Electrical gas purification
US2019291A (en) * 1933-04-29 1935-10-29 Air Conditioning Systems Inc Air conditioning system
US2060375A (en) * 1931-11-03 1936-11-10 Lyuho S Ishimura Making lead powder
US3186648A (en) * 1963-05-27 1965-06-01 Grace W R & Co Fluid energy mill
US3210058A (en) * 1964-03-06 1965-10-05 Oliver D Colvin Carburetor deicing device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB337448A (en) * 1929-01-09 1930-10-31 Siemens-Schuckertwerke Aktiengesellschaft
DE545603C (en) * 1929-01-10 1932-03-07 Siemens Schuckertwerke Akt Ges Pre-treatment of gases to be cleaned electrically

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1429973A (en) * 1920-04-29 1922-09-26 Charles Tagliabue Mfg Co Humidity controller
US1909825A (en) * 1928-08-01 1933-05-16 Int Precipitation Co Electrical gas purification
US1820734A (en) * 1929-01-09 1931-08-25 Siemens Ag Gas purifying plant
DE545426C (en) * 1929-04-20 1932-02-29 Siemens Schuckertwerke Akt Ges Device for automatic humidification, especially hot gases to be cleaned electrically
FR739811A (en) * 1931-07-09 1933-01-17 Siemens Ag Process for the preliminary treatment of gases intended to be purified electrically
US2060375A (en) * 1931-11-03 1936-11-10 Lyuho S Ishimura Making lead powder
US2019291A (en) * 1933-04-29 1935-10-29 Air Conditioning Systems Inc Air conditioning system
US3186648A (en) * 1963-05-27 1965-06-01 Grace W R & Co Fluid energy mill
US3210058A (en) * 1964-03-06 1965-10-05 Oliver D Colvin Carburetor deicing device

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3373944A (en) * 1966-02-24 1968-03-19 Bethlehem Steel Corp Method and apparatus for controlling consistency
US3989482A (en) * 1971-06-11 1976-11-02 Polysius Ag Method for the removal of dust from exhaust gases
US3923254A (en) * 1972-12-04 1975-12-02 Smidth & Co As F L Cement mill and method of starting same
US4400184A (en) * 1979-05-18 1983-08-23 Hitachi Shipbuilding And Engineering Company Limited System for recovering pressure and sensible heat from blast furnace gas with use of dry-type dust collector
US4642127A (en) * 1980-08-28 1987-02-10 Sumitomo Metal Industries, Ltd. Method for cooling blast furnace gas in an heat recovery system

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BE644935A (en) 1964-07-01
NL6402491A (en) 1964-09-14
DE1227769B (en) 1966-10-27
GB1002626A (en) 1965-08-25
CH421671A (en) 1966-09-30

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