JPH0714360B2 - Crystal can control method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sucrose process for performing concentrated crystallization of sugar in a refined sugar process, and particularly to a crystal can suitable for eliminating pseudocrystals generated in the sucrose process. Control method.

[Conventional technology]

The conventional method is disclosed in JP-A-57-110200 and Japanese Patent Application No. 59-1148.
No. 56, Japanese Patent Application No. 59-137439, Reference: Chemical Technology Journal
As described in MOL: January 1981, p. 47, hot water is supplied as one of the methods for eliminating pseudocrystals, which are undesired crystal nuclei other than seed crystals supplied to the crystal can, in the decoupling process. The water used to reduce the sugar concentration and the pressure to increase the equilibrium temperature of the liquid to increase the solubility of pseudocrystals were used together. This method brings about the above effect by opening the differential water valve and the vacuum break valve connected to the crystal can according to the set value of the hardness meter, and the timing of closing each valve is the elapsed time after opening the valve. I was doing.

[Problems to be Solved by the Invention]

In the above-mentioned prior art, the pressure in the crystal can is not constant due to factors such as seasonal fluctuations in the cooling water temperature of a barometric condenser used in a vacuum generator for evacuating the crystal can or deterioration of the capacity of the vacuum pump. , The time for extinguishing the pseudocrystal cannot be specified, and the operation after the pseudocrystal is extinguished is to stop the differential water and to vacuum the crystal can. It was performed after a set time including an excessive margin from the time when the vacuum breaking operation was started. However, excessive time prolongs the operation time of the decoction process, consumes the utility for operating the vacuum generator, and supplies more water than necessary, so the water is evaporated and the liquid is concentrated. There is a problem from the viewpoint of improving productivity and energy saving because the sucrose process consumes about 70% of heat energy of the refined sugar process.

An object of the present invention is to improve productivity and save energy in the sucrose process.

[Means for Solving the Problems]

The above-mentioned purpose is to start pseudo-crystals generated during crystallization using a vacuumed crystal can by setting the hardness meter provided in the crystal can to the water difference and vacuum break to the crystal can. In the method of controlling the crystal can to be extinguished, it is achieved by stopping the water difference and vacuumizing the crystal can when the liquid temperature in the crystal can reaches a predetermined value.

[Action]

According to the present invention, the temperature of the liquid equilibrating to the pressure rises due to the pressure difference due to the water difference to the crystal can and the vacuum break, and the solubility of the pseudocrystal increases.
Therefore, when the liquid temperature reaches that value, the water difference is stopped and the crystal can is evacuated to complete the process of eliminating pseudocrystals without spending excessive time and energy, improving productivity in the roasting process and saving energy. Can be planned.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the piping and instrumentation of the vacuum crystal can used in this example. The bottom of the vacuum crystal can 6 is provided with a hardness meter 2 for measuring the hardness of the white bottom, which is a mixture of sugar solution and crystals, and the sugar solution valve 4 is provided in a pipe for supplying the sugar solution to the vacuum crystal can 6. The differential water valve 3 for supplying hot water is connected downstream of the sugar solution valve 4. The vacuum crystal can 6 is a calandria type, and a heating steam valve 8 for supplying steam to the calandria is provided in the steam pipe. A can liquid thermometer 5 for measuring the temperature of the sugar liquid is provided in a portion of the vacuum crystal can 6 for storing the sugar liquid, and a pipe for supplying a seed crystal serving as a crystal nucleus at almost the same height as the can liquid thermometer 5. Seed valve 10 is connected. A vacuum break valve 7 and a vacuum crystal can 6 for introducing a gas into the upper part of the vacuum crystal can 6 to break the vacuum.
A barometric capacitor 11 for vacuuming is connected. A control device 9 for controlling the instruments attached to the vacuum crystal can 6 is provided.

Next, each operation of decoction will be described.

The vacuum break valve 7 is closed and cooling water is supplied to the barometric condenser 11 to evacuate the vacuum crystal can 6. When the vacuum crystal can 6 reaches a predetermined vacuum value of 60 mmHg, the sugar solution valve 4 is opened to a concentration of 70.
Fill the sugar solution of Bx (measured by a Brix refractometer) with sugar cane sugar or beet sugar to a level at which the calandria is sufficiently immersed. Open steam valve 8 for heating to 5K in Calandria
Supply the sugar solution with g / cm ² saturation to concentrate the sugar solution and replenish the sugar solution so that the calandria is not exposed to keep the liquid surface constant. When the sugar solution is concentrated to a supersaturation concentration of 76 Bx suitable for producing crystals, seed crystals of sugar cane sugar or beet sugar serving as crystal nuclei are introduced by opening the seed crystal valve 10. Immediately after the seed crystal was charged, the liquid in the can was in an unstable state because the surface area of the crystals present in the sugar solution was extremely small and the crystallization rate was slow compared to the rate at which the supersaturated concentration increased due to the evaporation of water in the sugar solution. Pseudocrystals occur which are crystals of undesired quality other than the grown crystals.

The operation of extinguishing the pseudo-crystals and growing only the seed crystals to increase the crystal content and make the grain sizes uniform will be described with reference to FIG. A seed crystal is put into the vacuum crystal can 6 to grow crystals, and the crystallization of the sugar solution lowers the supersaturated concentration of the solution in the can. Therefore, as the sugar solution is replenished, the proportion of crystals in the bottom white increases and The reading of the hardness gauge 2 measuring the lower hardness increases and the set value M1 reaches 50%. At that time, open the water valve 3 at 70 ℃
Of the vacuum break valve 7
Open and raise the pressure to raise the temperature of the parallel liquid. When the set value t ₀ of the can-liquid thermometer 5 reaches 78 ° C., the pseudocrystal melts and disappears, so the differential water valve 3 and the vacuum break valve 7 are closed.

As shown in Fig. 3, the indicated value of the hardness meter 2 increases and the set value M1
Open the staggered water valve 3 and the vacuum break valve 7 when the value reaches 50%, and before the reading of the canister thermometer 5 reaches the set value t ₀ of 78 ° C, the reading of the hardness gauge 2 reaches the set value M2. If it reaches 20%, there is no problem if the differential water valve 3 is closed and the vacuum break valve 7 is closed when the indicated value of the canister thermometer 5 reaches the set value t ₀ 78 ° C.

In this way, it is possible to accurately grasp the conditions under which the pseudo-crystals disappear by measuring the temperature of the can liquid, so that unnecessary steam is not wasted and vapor for evaporating it is not consumed excessively. It is possible to optimize the operation time for eliminating pseudocrystals and save energy without wasting the utility for increasing the pressure to make the vacuum again.

〔The invention's effect〕

According to the present invention, when the liquid temperature in the crystal can reaches a predetermined value, the water difference is stopped, and the crystal can is evacuated to eliminate pseudocrystals with the shortest operation time and the minimum energy. As a result, it is possible to improve productivity and save energy in the decoction process.

[Brief description of drawings]

FIG. 1 is a diagram showing piping and instrumentation of a vacuum crystal can according to an embodiment of the present invention, FIG. 2 is an operation explanatory view of the instrumentation shown in FIG. 1, and FIG. 3 is shown in FIG. FIG. 8 is a diagram illustrating another operation of the instrumentation. 1 ... Liquid level meter, 2 ... Hardness meter, 3 ... Differential water valve, 4 ...
… Sugar liquid valve, 5… Can liquid thermometer, 6… Vacuum crystal can, 7…
... Vacuum break valve, 8 ... Heating steam valve, 9 ... Control device,
10 …… Seed crystal valve, 11 …… Barometric condenser

Claims (2)

[Claims] 1. A water differential to the crystal can and a vacuum break, in which pseudo-crystals generated during crystallization using a vacuum-formed crystal can are started by a set value of a hardness meter provided in the crystal can. A method of controlling a crystal can, wherein the crystal water is stopped by stopping the water difference when the liquid temperature in the crystal can reaches a predetermined value. 2. The method of controlling a crystal can according to claim 1, wherein the crystallization is decoction of a refined sugar process.