JPS63169999A - Program control of crystallizing boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to improving the controllability of a crystal can program control method.

<Prior Art> The configuration of an automatic sugar brewing device using a crystal can will be explained with reference to FIG. A solution F to be condensed into an upright crystallizer 1 having a calandria-type heating section 2 is introduced into a conduit 3. It is supplied into the can via the II section valve 4. Heated steam S is supplied to pipe 5 and mr
It is supplied to the heating section 2 inside the crystal can via the H valve 6.

The solution is concentrated by heating and evaporated, and at the same time, the solution is replenished, and when it reaches a crystallization concentration that allows crystal precipitation, sugar species are added to the solution from the injector 7 through the sugar species valve 8 into the can. to generate crystal nuclei suitable for each variety. After that, in order to prevent these crystal nuclei from combining with each other and from generating new crystal nuclei (components) of undesired species, the pipe line 9 is adjusted according to the hardness of the white bottom inside the can. .11 Water difference W or '' is supplied through the control valve 10 or the solution F is supplied through the pipe line 3 and the control valve 4 to continue concentration and crystal growth.

When the crystals grow to a certain extent and the volume of the crystals in the white area per unit volume exceeds a certain value, and the crystals become quite close to each other, it becomes relatively difficult for parts to occur, and further condensation occurs. , facilitates the growth of crystals and supplies a solution, and when the volume inside the can increases to a certain value and the grain size of the crystals grows to a required size, Shishita F is discharged from the can through the discharge valve 11. . The discharged shiroshita is separated into crystals and a solution using a centrifuge, and the solution is repeatedly used to make decoction sugar.

The vapor evaporated from the bottom inside the crystallizer is drawn through a condenser 12 by a pump 13 and condensed.

Reference numeral 14 denotes a cooling water supply pipe line to the condenser.

The degree of vacuum, that is, the pressure inside the can, is controlled to be constant by a control valve 15 that controls the amount of air supplied into the can. 16
is a pressure sensor inside the can, PVp is its measured value, 17 is a pressure regulator, pressure measurement 111PVP and control device 18
The operation output M is obtained by inputting the pressure set value SVp supplied via the manual automatic switch 19 and performing control calculations on the deviation.
VP is supplied to the IS valve 15 to control the pressure inside the can to SVp.

20 is a rheometer that measures the hardness of the white inside the can, and PVR is its measured value; 21 is a level sensor that detects the level of the white inside of the can; P V u is the measured value. These measured values PVe and PV++ are input to the control device 18.

MVp and MVw are manual and automatic switchers 22.2 respectively.
3 to the control valve 4.10.

The normal f, IJ a11 method in such a configuration is:
As shown in Figure 3<A), the setting with the hardness measurement (
At the timing when fl B + is reached, as shown in (B), the control valve 10 or 4 is opened for a certain period of time to supply the difference water or solution into the can to loosen the solidity and then concentrate. When the hardness reaches the set value B2, which is higher than the previous set value B, the same operation is performed to gradually increase the hardness and level while growing the crystals.

Once the hardness is loosened by supplying water or a solution, it is a spore (a mass of solute that is neither liquid nor solid, and has both liquid and solid properties) that is closely related to crystal growth.

As a document, 5ICE'86July23-25
Tokyo, ESL 1-4) At the point where the growth rate is increased to the limit point for single crystal generation, this is disrupted by adding water or a solution, thereby maintaining the crystallization rate at the maximum speed without generating any parts. This is to enable sugar,
This is the basic method of so-called intermittent roasting.

<Problems to be solved by the invention> In the case of an intermittent brewing sugar method using intermittent water or solution supply,
In order to concentrate to the next hardness set value, heating energy is required to evaporate the supplied water. In order to avoid this energy consumption, the applicant proposed an operation equivalent to supplying water or solution.
It is made of No. 00.

This operating method consists of 1, . 1
At the timing of 2, steady pressure setting 1iaS V
An operation is performed to increase P + by a certain period T. Temporary pressure increase, for example, normal pressure is 7001! e g600+em
g, and as a result, the boiling point of Shishita increases by about 10℃,
The degree of supersaturation in the white bottom is reduced, and an effect equivalent to that of differential water or solution supply is obtained.

However, due to the operation of rapidly changing the degree of vacuum inside the can, the amount of spores, which is closely related to crystal growth, fluctuates.

In other words, the phenomenon of solutes forming spores and the phenomenon of solutes being dissolved from spores are greatly affected by small unsteady disturbances and large disturbances forced by changes in the degree of vacuum. On the other hand, the dynamics of the process varies greatly, and a pressure control system with the same gain will have a problem of poor fl and 4J controllability.

An object of the present invention is to provide a control method that does not reduce controllability in response to such periodic disturbances.

Means for Solving the Problems> The method of the present invention is characterized by having a vacuum degree control means for controlling the degree of vacuum in the crystal can, and each time the hardness of the white bottom in the can reaches a set value, The purpose of the present invention is to temporarily lower the degree of vacuum from a steady value and to change the gain of the degree of vacuum control means.

Effect> According to the present invention, the gain of pressure regulation is controlled to change in synchronization with the period in which the degree of vacuum inside the can is controlled at a constant level of 1ffit+.

<Example> As shown in Fig. f53 (C), the optimal gain for each zone is set by the gain setting signal QG from the υJ control device 18 in the a zone where the pressure rise is controlled t11 and the b zone where the steady pressure is controlled. is set on the pressure regulator 17. For example, in the b zone, the proportional band is 10% to 3096.

Integration time is 15 to 30 minutes, and proportional band 2 in zone a.
%, 11Ik minutes time is set to 10 minutes.

The configuration of the pressure regulator section is a single adjustment 31 as shown.
An effective configuration is to change the gain from the control device side.

In general, the capacity of the ejector and vacuum pump for vacuum setting is not constant depending on each factory, and the dynamics when breaking the vacuum and when creating the vacuum are different, so set an appropriate valve opening for each action of the control valve. This is because it is necessary.

Although it is possible to control the vacuum am using the control valve 15 together with differential water and solution supply, the amount of differential water and solution supplied in that case would be very small.
The program for returning to the zone is a certain slope or bend as shown in Figure 2.

It is necessary to change the curve gently.

<Effects of the Invention> As explained above, according to the present invention, the control gain of pressure regulation is optimized for controlling the growth and collapse of spores during the period when the degree of vacuum inside the can is changed and during the steady state period. It becomes possible to operate with a large gain, and controllability can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a crystal can control device to which the method of the present invention is applied, FIG. 2 is an explanatory diagram of its operation, and FIG. 3 is an explanatory diagram of the operation of a conventional control method.

Claims (1)

[Claims] It has a vacuum degree control means for controlling the degree of vacuum in the crystal can, and each time the hardness of the white bottom in the can reaches a set value, the vacuum degree is temporarily lowered from a steady value, and the vacuum degree control means A crystal can program control method characterized by changing the gain of.