US3680621A - Crystallization installation with control system - Google Patents

Crystallization installation with control system Download PDF

Info

Publication number
US3680621A
US3680621A US19069A US3680621DA US3680621A US 3680621 A US3680621 A US 3680621A US 19069 A US19069 A US 19069A US 3680621D A US3680621D A US 3680621DA US 3680621 A US3680621 A US 3680621A
Authority
US
United States
Prior art keywords
cells
cell
last cell
solution
crystallized
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US19069A
Other languages
English (en)
Inventor
Jean Claude Giorgi
Georges Windal
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fives Lille Cail
Original Assignee
Fives Lille Cail
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fives Lille Cail filed Critical Fives Lille Cail
Application granted granted Critical
Publication of US3680621A publication Critical patent/US3680621A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D21/00—Control of chemical or physico-chemical variables, e.g. pH value
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D1/00—Evaporating
    • B01D1/0082—Regulation; Control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0018—Evaporation of components of the mixture to be separated
    • B01D9/0031—Evaporation of components of the mixture to be separated by heating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0036—Crystallisation on to a bed of product crystals; Seeding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D9/00—Crystallisation
    • B01D9/0063—Control or regulation
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D11/00—Control of flow ratio

Definitions

  • the present invention relates to installations for crystallizing the solute from a solution, such as sugar from sugar juice, by evaporation of the liquid solvent in a continuous operation, and more particularly to a control system for such installations.
  • installations for producing sugar crystals from sugar juice include a plurality of successive crystallization cells interconnected for passing the juice to be crystallized successively from a first cell to intermediate cells and then to alast cell.
  • An inlet pipe supplies the juice to the first cell and an outlet pipe removes the crystallized product from the last cell.
  • Steam heating means such as single or a series of radiators, is arranged in the cells for evaporating liquid in each of the cells, and means is provided for delivering steam to the heating means.
  • the control system comprises a first control for regulating the feed rate of the undersaturated solution to the last cell or of the steam pressure in the heating means therein, a measuring element for measuring the percentage of crystals or solute in the crystallized product removed from the last cell, the measuring element producing an output signal responsive to the measured percentage and operating the first control.
  • a second control regulates the feed rate of the undersaturated solution to at least one of the intermediate cells, or a group thereof, or of the steam pressure in the heating means therein, and a resistancecapacity system receives the output signal from another measuring element measuring the feed rate of undersaturated solution to the last cell, which is a function of the output signal of the first-named measuring element, and transmits the same to the second control.
  • the time constant of the latter system increases with the distance of the intermediate cell or group of cells from the last cell.
  • an apparatus for the continuous crystallization of sugar from sugar-containing juice whichincludes a horizontally disposedcylindn'cal tank T sub-divided by partition walls 12 into'seven cells or compartments 1 to 7, any suitable number of crystallization cells being usable, of course.
  • Heatingmeans is provided ineach cell, which may take any suitable form, the illustrated heating means comprising a radiator 14 passing through, and common to, all cells.
  • the valve 18' is actuated by a pneumatic servo motor with a control relay and the servo motor is operatedby air pressure regulated by control element 20, as a direct function of the-pressure drop created by a diaphragm l9 placed in the main 1.6 downstream of valve 18, this pressure drop being a function of the steam output coming from the valve.
  • the product to be crystallized is a sugar-containing juice which has been concentrated in a non-illustrated apparatus and mixed with seed crystals.
  • This mixture or massecuite is fed to the first cell 1 of tank T by feed pipe 22 which carries a double-seated valve 24 for controlling the flow of the mixture into the cell.
  • Valve 24 is actuated by a pneumatic servo motor operated by air pressure regulated by control element 23, as a direct function of the pressure drop created by a diaphragm 25 placed in the feed pipe. 22 downstream of valve 24, this pressure drop being a function of the output'of massecuite coming from valve 24.
  • the juice and seed crystal mixture then passes to and through succeeding cells through the'last cell 7 through outletB of pipe-32.
  • the feeding of the undersaturated juice to the first two cells 1 and 2 is so controlled that the concentration of the juice is at a predetermined value corresponding to the supersaturation thereof at the temperature of the juice.
  • the concentration of the juice depends on the temperature thereof which is measured in each of these two cells.
  • the undersaturated juice is fed to each of function of the difference of the boiling temperature of water and that of the juice, at, equal pressures, these temperatures being measured by temperature probes 27 and 27'in the cells 1 and 2. Probes 27 are immersed in the juice and measure the temperature of the juice.
  • the boiling temperature of water is equal to the temperature of the vapor produced in the cells and is measured by probes 27' positioned in the upperpart of the cells.
  • control element 26 operates the associated valve 28 so that the feed rate of the undersaturated Q juice is changed and the two values become equal.
  • the feeding of the undersaturated juice to the next cells is so controlled that it varies as a function of the percentage of crystals or solute of the product removed from the installation at B.
  • the percentage of crystals or dry matter in the product is measured in the pipe 32 by densimeter 30 of any suitable and conventional type.
  • the undersaturated juice is fed to the last cell 7 by double-seated valve 36 actuated by a servo motor of the same type as that for valves 24 and 28, the servo motor being operated by air pressure regulated by control element 34 of the same type as element 26, as a direct function of the'density of the product leaving the installation at B.
  • this density is measured by a gamma-ray densimeter mounted in the output" pipe 32, the densimeter producing an electrical control signal which is applied to control element 34 by means of' an 'electro-pneumatic converter or transfeeding each of cells 3 to 6 so that the feed rate to each cell may be regulated in a predetermined ratio.
  • the main valve 40 for the four cells 3 to 6 is again actuated by a pneumatic servo motor with a control relay, which is operated by air pressure regulated by control element 46 of the same type as element 23, as a direct function of the amount of juice fed into cell 7.
  • Q diaphragm 38 in thefeed pipe delivering juice to cell 7 produces a control signal proportional to the pressure drop which it creates, this pressuredrop being a function of the amount of juice fed into the cell.
  • This signal is transmitted to control element 46 so that the-operating signal of the control element is a function of the V feed rate of the undersaturated juice to the last cell 7,
  • The, control signal which regulates the operating signal of control 46 is produced by device 48 to which is applied a signal proportional to the feed rate at cell 7, via a resistance-capacity system 50.
  • the resistancecapacity system may be electric, pneumatic, hydraulic, etc.
  • the device 48 produces an output signal which is a linear function of the input signal applied to it so that the output I of the pipe 42 isstabilized according to the equation J aj'7 b, a and b being constants, and 17 being the feed rate of diluted juice to cell 7.
  • the device 48 is such that the values of a and b may be adjusted as a function of the properties of the product to be crystallized, b having the value zero, if desired.
  • the device 48 is an analogue computer.
  • this computer is constituted by a simple diaphragm which may be biased by a spring.
  • the pressure P constitutes the output signal and serves to control output J of pipe 42.
  • the resistance-capacity system 50 which transmits the output signal of element 38 to device 48, acts as a lowpass filter. It serves to reduce the speed of variation of this output signal so that thevariations of the juice feed rate to cell 7, under the influence of control 36,
  • the system 50 also serves to dampen the signal coming from element 38, i.e., to reduce its amplitude, when this signal varies rapidly in one sense-or the other. This variation is considered rapid when its duration is less than the time constant of the system 50. This time constant is substantially equal to the time required to pass the product through crystallization cells 3 to 7.
  • the illustrated embodiment comprises pneumatic controls and, thus, the system 50 is constituted by a closed capacity chamber connecting the element 38 and device 48.
  • the output face of diaphragm 38 faces a diaphragrns l9 and 25, diaphragm 38 is a disc having a
  • the percentage of crystals or dry matter in the product removed at B is maintained equal to its predetermined value by acting rapidly on the feed rate to the last cell 7 while acting more slowly on the feed rate to intermediate cells 3 to 6.
  • each valve 44 could be individually operated by analogous control systems in which the constants a and b, and the time constants are individually adjusted. Similarly, groups of cells may be separately controlled in an analogous manner.
  • control 34 may be used, or any parameter proportional to these signals.
  • the device 48 will be replaced by another device delivering an output signal which is used by control 46 for controlling valve 40.
  • the operation of the installation may be controlled by acting on the steam pressure in the heating means, and such a control may be effected according to the invention by providing separate radiators for each crystallization cell or each group of crystallization cells.
  • An installation of this type has been operated with a daily output of 365 tons of white sugar, by delivering 8.75 tons of steam per hour to main l6 and 8.75 tons of massecuite per hour to feed pipe 22.
  • a total of 32.3 tons of unsaturated juice was fed per hour into line 42, the branch line to valve 28 feeding cell 1 receiving 3 tons per hours, the branch line to valve 28 feeding cell 2 receiving 4.3 tons per hour, the branch line to valve 40 receiving 21 tons per hour and the branch line to valve 36 receiving 4 tons per hour.
  • the hourly output through pipe 32 at B was 32.3 tons per hour.
  • Valve 18 is a throttle valve having a maximum steam throughput of l0.7 tons per hour.
  • Valve 24 has a maximum sugar juice throughput of 12 tons/hour and valves 28 have a maximum sugar juice throughput of 4.5 tons/hour for cell 1 and 7.5 tons/hour for cell 2.
  • the maximum throughput of valve 36 also is 7.5 tons/hour, while that of valve 40 is 40 tons/hour.
  • a crystallization installation with a control system in which the solute of a liquid solvent is crystallized by evaporation of the liquid solvent in a continuous operation, comprising 1. a plurality of successive crystallization cells including a first cell, a last cell and intermediate cells therebetween;
  • inlet means for supplying a solution to be crystallized to the first cell
  • first control means for regulating the supersaturation and the viscosity of the solution in the last cell
  • measuring means operable to generate first and second output signals responsive to the percentage of crystallized solute or dry matter in the product in the last cell
  • the measuring means operating the first control means as a function of the first output signal
  • a second control means for regulating the supersaturation and the viscosity of the solution in at least one of the intermediate cells as a function of said second output signal
  • the measuring means includes a first measuring element for measuring the percentage of crystallized solute or dry matter in the product removed from the last cell, said first measuring element producing said first output signal, and a second measuring element for measuring the feed rate of undersaturated solution to the lat cell regulated by the first control means, said second measuring element producing another output signal.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Thermal Sciences (AREA)
  • Non-Alcoholic Beverages (AREA)
  • Apparatus Associated With Microorganisms And Enzymes (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Seasonings (AREA)
  • Food Preservation Except Freezing, Refrigeration, And Drying (AREA)
US19069A 1968-03-04 1970-03-12 Crystallization installation with control system Expired - Lifetime US3680621A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR142174 1968-03-04

Publications (1)

Publication Number Publication Date
US3680621A true US3680621A (en) 1972-08-01

Family

ID=8646903

Family Applications (1)

Application Number Title Priority Date Filing Date
US19069A Expired - Lifetime US3680621A (en) 1968-03-04 1970-03-12 Crystallization installation with control system

Country Status (8)

Country Link
US (1) US3680621A (enrdf_load_stackoverflow)
BE (1) BE728922A (enrdf_load_stackoverflow)
DE (1) DE1910985B2 (enrdf_load_stackoverflow)
ES (1) ES364338A1 (enrdf_load_stackoverflow)
FR (1) FR1588799A (enrdf_load_stackoverflow)
GB (1) GB1227701A (enrdf_load_stackoverflow)
NL (1) NL6903353A (enrdf_load_stackoverflow)
PL (1) PL69880B1 (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3879215A (en) * 1972-08-24 1975-04-22 Hyesons Sugar Mills Limited Compartmentalized vacuum pan for crystallization of sugar
US3899386A (en) * 1971-12-29 1975-08-12 Hitachi Ltd Method for controlling vacuum pan
US4009045A (en) * 1976-04-21 1977-02-22 Godchaux-Henderson Sugar Co., Inc. Continuous crystallization process and apparatus
US4056364A (en) * 1974-08-30 1977-11-01 Amstar Corporation Two stage continuous crystallization apparatus with controls
US4119436A (en) * 1977-05-23 1978-10-10 Buttes Gas & Oil Co. Sugar refining process
US4120745A (en) * 1975-09-01 1978-10-17 Csr Limited Semi-continuous vacuum pan system
US4162927A (en) * 1972-11-13 1979-07-31 Morfin Alvarez Rafael Apparatus for crystallizing sugar solution and mother liquors continuously by evaporation
CN104107818A (zh) * 2014-07-18 2014-10-22 中国天辰工程有限公司 一种己二酸结晶器的移动清疤方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3032922A1 (de) * 1980-09-02 1982-04-15 Hein, Lehmann AG, 4000 Düsseldorf Verfahren und vorrichtung zur erzeugung eines gemisches aus zucker und aufloesefluessigkeit

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1410215A (fr) * 1964-01-27 1965-09-10 Fives Lille Cail Et Sucreries Procédé et système de régulation pour un appareil de cristallisation
FR1444229A (fr) * 1965-05-21 1966-07-01 Fives Lille Cail Procédé et système de régulation d'un réacteur du type à cellules ou piston-flow
US3424221A (en) * 1966-06-06 1969-01-28 Gene W Luce Apparatus and method for continuous crystallization by evaporation

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1410215A (fr) * 1964-01-27 1965-09-10 Fives Lille Cail Et Sucreries Procédé et système de régulation pour un appareil de cristallisation
FR1444229A (fr) * 1965-05-21 1966-07-01 Fives Lille Cail Procédé et système de régulation d'un réacteur du type à cellules ou piston-flow
US3424221A (en) * 1966-06-06 1969-01-28 Gene W Luce Apparatus and method for continuous crystallization by evaporation

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Harriott, Process Control, 187 191, McGraw Hill, New York, 1964. *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3899386A (en) * 1971-12-29 1975-08-12 Hitachi Ltd Method for controlling vacuum pan
US3879215A (en) * 1972-08-24 1975-04-22 Hyesons Sugar Mills Limited Compartmentalized vacuum pan for crystallization of sugar
US4162927A (en) * 1972-11-13 1979-07-31 Morfin Alvarez Rafael Apparatus for crystallizing sugar solution and mother liquors continuously by evaporation
US4056364A (en) * 1974-08-30 1977-11-01 Amstar Corporation Two stage continuous crystallization apparatus with controls
US4120745A (en) * 1975-09-01 1978-10-17 Csr Limited Semi-continuous vacuum pan system
US4009045A (en) * 1976-04-21 1977-02-22 Godchaux-Henderson Sugar Co., Inc. Continuous crystallization process and apparatus
US4119436A (en) * 1977-05-23 1978-10-10 Buttes Gas & Oil Co. Sugar refining process
CN104107818A (zh) * 2014-07-18 2014-10-22 中国天辰工程有限公司 一种己二酸结晶器的移动清疤方法
CN104107818B (zh) * 2014-07-18 2016-03-09 中国天辰工程有限公司 一种己二酸结晶器的移动清疤方法

Also Published As

Publication number Publication date
ES364338A1 (es) 1970-12-16
GB1227701A (enrdf_load_stackoverflow) 1971-04-07
BE728922A (enrdf_load_stackoverflow) 1969-08-01
DE1910985A1 (de) 1969-09-25
FR1588799A (enrdf_load_stackoverflow) 1970-03-16
PL69880B1 (enrdf_load_stackoverflow) 1973-10-31
DE1910985B2 (de) 1971-12-30
NL6903353A (enrdf_load_stackoverflow) 1969-09-08

Similar Documents

Publication Publication Date Title
US3680621A (en) Crystallization installation with control system
US3725127A (en) Method and system for controlling a crystallization installation
US4009045A (en) Continuous crystallization process and apparatus
US2576496A (en) Method for controlling multipleefect evaporators
Castro et al. Dynamic simulation of multiple-effect evaporation
US2767133A (en) Fractionation process and apparatus
DK144408B (da) Fremgangsmaade til regulering af cellers tilfoersel af umaettet oploesning eller af cellernes opvarmning i en kontinuerligt arbejdende fordampningskrystallisator og anlaeg til udfoerelse af fremgansmaaden
US3356124A (en) Control arrangement for a multiple effect evaporator
US3203466A (en) Apparatus for concentrating liquids
US2587293A (en) Sugar crystallizing process
EP0244079B1 (en) Process and apparatus for controlling the composition of a mixture leaving an evaporator
US491659A (en) Process of evaporating liquids
US2954304A (en) Process and apparatus for the production of starch syrup
US4050953A (en) Process for continuously producing sugar
Burton et al. Comparison of milks processed by the direct and indirect methods of ultra-high-temperature sterilization. I. An experimental ultra-high-temperature sterilizer and its characteristics
US28570A (en) Improvement in apparatus for evaporating saccharine juices
FR2562908A1 (fr) Procede de conduite automatisee d'un appareil de cristallisation a marche continue pour la production de sucre
US1598301A (en) Evaporator plant
EP0436763A1 (de) Verfahren zur kontinuierlichen Herstellung von Kristall-Magma
US746736A (en) Apparatus for extracting sugar.
Tejerina et al. Modelling and simulation of the non-ideal mixing behaviour of the crystallization stage in a sugar factory batch crystallizer
SU1018662A1 (ru) Способ автоматического управлени процессом выпаривани
US667850A (en) Method of sugar-boiling.
DE1910985C (de) Verfahren und Vorrichtung zur Regelung einer kontinuierlich arbeitenden Verdampfungskristallisationsanlage
SU82294A1 (ru) Способ непрерывного выпаривани