JPH0691101A - Method for concentrating solution by using heat transfer medium and device therefor - Google Patents

Abstract

PURPOSE:To increase the efficiency of heat transfer of a heat exchanger in a heating part and to improve the heat efficiency of a heat pump by performing heating evaporation and cooling condensation, thereby concentrating solution while diluting solution, such as photographic processing waste with water and lowering the concentration of incorporated components. CONSTITUTION:In an evaporating concentration of a heat pump type, with which the heating evaporation of solution and the cooling condensation of evaporated vapor are performed by using a heat transfer medium to concentrate the solution, a water feeding means 75 for diluting the solution with water in a process till concentration and a time sequential water feeding control means 76 for solution are provided, that is, operation is performed while solution is diluted with water in a process until concentration to lower the concentration of components incorporated. Thus, the concentration of odorous gas in condensed distilled water obtained by giving evaporating concentration to solution, particularly photographic processing waste is lowered to recycle the distilled water and, simultaneously, the dirt in an evaporating column is eliminated and the durability is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for evaporating and concentrating an aqueous solution, for example, a photographic processing waste solution of a silver halide photographic light-sensitive material. More specifically, the present invention relates to a method and apparatus for efficiently promoting evaporative concentration when evaporating and concentrating to separate and remove distilled water, and reducing the content of distilled water.

[0002]

2. Description of the Related Art Generally, photographic processing of a silver halide photographic light-sensitive material is carried out by developing, fixing, washing with water in the case of a black-and-white light-sensitive material, and color development, bleach-fixing (or bleach-fixing) in the case of a color light-sensitive material. ), Washing with water, stabilization, etc., or a combination of steps using a treatment liquid having two or more functions.

In a photographic process for processing a large amount of light-sensitive material, while a component consumed by the process is replenished, a component which elutes in the process solution by the process or is concentrated by evaporation (for example, bromide ion in a developing solution). , Such as silver complex salt in the fixing solution) to keep the components of the processing solution constant so that the replenishing solution is used as a replenisher for the above replenishment. It is replenished and part of the processing liquid is discarded for removal of thickening components in photographic processing.

In recent years, the replenisher has been changed to a system in which the amount of replenisher is drastically reduced, including wash water, which is a replenisher for washing, for pollution and economical reasons. It was guided from a processing tank by a waste liquid pipe, diluted with a waste liquid of washing water, cooling water of an automatic processor, etc., and then disposed of in sewers or the like.

However, with the recent strengthening of pollution control, it is possible to dispose of washing water and cooling water in sewers and rivers, but other photographic processing solutions [eg developing solution, fixing solution, color developing solution, Bleach-fixing solution (or bleaching solution, fixing solution),
It is virtually impossible to dispose of the stabilizing solution, etc.]. For this reason, each photo processing company has a waste liquid processing company paying a recovery fee to collect the waste liquid and installing a pollution processing facility. However, the method entrusted to a waste liquid treatment company requires a considerable space to store the waste liquid, and is extremely expensive in terms of cost.
Further, the pollution control equipment has drawbacks such as an extremely large initial investment (initial cost) and requiring a considerably large area for maintenance.

Further, specifically, as a pollution treatment method for reducing the pollution load of the photographic processing waste liquid, an activated sludge method (for example, Japanese Patent Publication Nos. 51-12943 and 51-7952),
Evaporation method (JP-A-49-89437 and JP-A-56-33996), electrolytic oxidation method (JP-A-48-84462, JP-A-49-119458, JP-B-53-
43478, JP-A-49-119457, etc.), ion exchange method (JP-B-51-37704, JP-A-53-383, JP-B-53-43271, etc.), reverse osmosis method (JP-A-50- No. 22463) Chemical treatment method (JP-A-49-64257, JP-B-57-37396, JP-A-53-12152)
No. 49-58833, No. 53-63763, No. 57-37395, etc.), but these are not yet sufficient.

On the other hand, due to restrictions on water resources, rising water supply and drainage costs, simplicity of automatic developing machine equipment, and working environment around the automatic developing machine, in recent years, a stabilization process which replaces washing with water has been used. Automatic processor that does not require piping for water supply / drainage outside the processor (so-called anhydrous washing automatic processor)
Photo-processing by the is becoming popular. In such a treatment, it is desired that the cooling water for controlling the temperature of the treatment liquid be omitted. In such photographic processing that does not substantially use rinsing water or cooling water, the pollution load is extremely large because it is not diluted with water as compared with the case where there is photographic processing waste liquid with rinsing water or cooling water from an automatic processor. On the other hand, there is a feature that the amount of waste liquid is small.

Therefore, due to the small amount of this waste liquid,
It is difficult to move after installation because it is possible to omit the piping outside the machine for the waste liquid supply, which is considered to be a drawback of the conventional automatic developing machine, and the foot space is narrow, and piping work at the time of installation The disadvantages such as that it requires a lot of cost and energy cost of hot water supply pressure are solved,
Compact enough to be used as an office machine,
The enormous advantage is achieved that simplification is achieved.

On the other hand, however, the waste liquid has a very high pollution load, and it has become impossible to flow the waste liquid not only in rivers but also in sewers in view of the pollution regulations. Further, although the amount of waste liquid in such a photographic process (a process in which a large amount of running water is used and washing is not performed) is small, for example, even in a relatively small-scale color processing laboratory, the amount is about 10 l / day.

Therefore, generally, the waste liquid is collected by a waste liquid collecting company, and is secondarily and tertiaryly treated to be harmless. However, not only the waste liquid collecting price becomes higher year by year due to the soaring collection cost, but also the collection efficiency is poor in a minilab. For this reason, it is difficult to get them to collect the waste, which causes a problem that the waste liquid fills the store.

On the other hand, in order to solve these problems, it has been studied to heat the photographic processing waste liquid to evaporate it to dryness or solidify it so that the photographic processing waste liquid can be easily processed in a minilab or the like. There are, for example, Shokai 60-7
It is shown in 0841.

[0012]

Although such an evaporative concentration method and apparatus developed by the present applicant have achieved quite efficient evaporative concentration, it is not yet sufficient, and the concentration column is slightly heated. It causes a lot of odor generation, and the inside of the device is extremely dirty and the durability is poor. Further, there is a problem that it may be difficult to reuse the distilled water that is evaporated and recovered as it is.

It is an object of the present invention to provide a solution concentrating method and apparatus which further solves such problems.

[0014]

This object is achieved by any of the following technical means a and b.

(A) In a method using a heat pump type evaporative concentrator for concentrating the solution by heating and evaporating the solution by using a heat medium and cooling and condensing the evaporative vapor, during the process of concentrating the solution. A heat medium characterized by being diluted with water to increase the heat transfer efficiency of the heating part heat exchanger and improving the heat efficiency of the heat pump by operating while diluting with water and decreasing the concentration of the contained components. Solution concentration method.

(B) A heat pump type evaporative concentrator for concentrating the solution by heating and evaporating the solution using a heat medium and cooling and condensing the evaporative vapor. A solution concentrating device using a heat medium, comprising: a water supply means for diluting with a solution; and a time-series water supply variable control means for the solution.

[0017]

EXAMPLES Examples of the solution concentrating method and apparatus of the present invention will be described with reference to the schematic view of FIG. A photographic processing waste liquid was used as the solution.

The photographic processing waste liquid is injected and stored in the evaporative concentration column 1 that can withstand a reduced pressure, and the cooling and condensation column 1A is provided on the outer side substantially concentric with the column 1. The pressure reducing means 7B was connected to the pressure reducing means to reduce the pressure. It is known that under a reduced pressure lower than atmospheric pressure, boiling occurs below the boiling point of itself, and in this embodiment, vaporization at a low temperature at which gas generation is unlikely to occur is performed under this reduced pressure. Next, a heating means 2 arranged three-dimensionally is provided in the column 1, and the lower portion of the heating means 2 is immersed in the storage portion 4 for the photographic processing waste liquid to heat the photographic processing waste liquid. The upper part thereof projects from the storage portion of the photographic processing waste liquid and is in the air, and in this portion, the photographic processing waste liquid is supplied from a waste liquid storage tank (container) 31 to a solution feeding means 3 including an electromagnetic valve 6A and a liquid feeding pump 7. Is sprayed from the upper nozzle 7A, fed into the column, heated and evaporated under reduced pressure, and repeatedly heated and evaporated in the spraying and dropping process to efficiently and rapidly concentrate.

At this time, if the concentration of the solution is high, heating and evaporation are accelerated in the process of spraying and dropping the solution, the temperature of the column is increased, and odor and the like and the bumping phenomenon are accompanied. Further, when the concentration is high, the water contained in the solution is poorly separated from other components, and the heat transfer efficiency with the heat exchanger is reduced. As a means for improving this separation and improving heat transfer efficiency, it has come to be considered desirable to inject and dilute tap water according to the concentration concentration.

As the injection dilution means, an injection device and its control device as shown in FIG. 1 are added. 72 tap water
Are collected in the evaporation column 1 and sprayed from above through a nozzle 75 connected to a pipe 74 via an electromagnetic valve 73.

The detection values of the electromagnetic valves 73 and 6A, the drive circuit of the pump 7 and the level detector 64 of the evaporative concentration column 1 are connected to the controller 76. The supply amount of tap water from the water tank 72 is controlled to be appropriate with respect to the supply amount of the solution from the storage tank 31.

In the control, the dilution ratio of the solution is controlled to be in the range of more than 1 time and less than 10 times.

The water level in the water tank 72 is detected by the mechanical level detector 71, and the tap water is automatically maintained by the mechanical valve. In the present embodiment, the injection of tap water or the like is sprayed directly into the solution heated in the evaporation column, but it may be agitated after the injection. The diluted solution may be injected into the evaporative concentration column 1 after injecting water to a diluted state.

The control of the injection amount may be performed in the same manner as in the means of this embodiment.

Further, this reduces the content of components other than water with respect to the total amount of distilled water, and has an advantage that no special treatment is required for reuse.

Then, the unstable phenomenon such as the bumping phenomenon is eliminated, the inside of the evaporation column and the like are eliminated, and the durability of the apparatus is improved.

The water vaporized in this manner forms a spiral pipe shape which also forms a guide for condensed water in the cooling condensing column 1A which communicates with a communication part provided in the upper part of the evaporative concentration column 1. The cooling means 8A and the water receiver 8C at the bottom of the column 1A are provided so as to contribute to downsizing and stabilization of reduced pressure in both columns. On the other hand, the components which are solidified to a high concentration by repeating the above-mentioned evaporative concentration are collected by the stirring blades at the bottom of the evaporative concentration column 1 to the peripheral discharge port, and received and collected in the container 12 connected to the lower part. The reason why the heating means 2 is three-dimensionally arranged in the liquid and the air in the present invention is that the in-liquid portion is mainly for preheating of the photographic processing waste liquid, and the air portion is sprayed and dropped onto the photographic processing waste liquid or contact with tap water. It has the effect of increasing the area, and is effective for uniformly and efficiently performing low-temperature evaporation without gas generation for the solution in the above-mentioned moderately diluted state. Further, the cooling / condensing column 1A provided concentrically with the evaporative concentration column 1 is provided with a cooling means 8A so that water vapor entering through the communicating portion is captured, cooled and condensed, and collected as water droplets. This has the effect of reducing the pressure reduction balance in both columns due to the generated steam, and applying a large load to maintain the prescribed pressure reduction state in the pressure reducing device 7 (in this embodiment, an ejector is used). . That is, the generated steam immediately cools and condenses where the pressure in both columns rises, thereby suppressing the pressure rise.

In this structure, if the temperature of the submerged portion of the heating means 2 is set to the optimum temperature for the reduced pressure evaporation, the portion of the heating means 2 in the air that is integral with the heating means 2 is controlled at the same temperature, and there is a difference in electrothermal effect. However, the substantial surface temperature of the part in the air becomes high, and if this touches the photoprocessing waste liquid, unpleasant gas may be generated due to rapid heating.Therefore, the dilution degree of the photoprocessing waste liquid supplied from above should be as described above. It is preferable to control and control the amount.

Further, as described above, the heating means 2 and the cooling means 8A used heat pumps in the present invention. Then, the water vapor comes into contact with the surface of the cooling means and condenses to form water droplets, which then travel along the cooling means 8A and are collected in the water recovery container 9. The surface temperature of the heating means 2 is preferably 100 ° C
In order to prevent the generation of odorous gas, the temperature should be 20 ℃ -60 ℃.
Is most preferred.

The heat radiating portion of the heat pump is used for the heating means 2, and the heat absorbing portion of the heat pump is used for the cooling means 8A and the cooling means 8B provided in the water recovery container 9.

A charge pipe 25 for charging a condenser of a heat pump constituting the heating means 2, a capillary tube 26 functioning as an expansion valve arranged after the heating means 2, and an outer side of the cooling means 8A are provided. A compressor 21 for compressing a refrigerant, an air-cooling condenser 22 for air-cooling and condensing the compressed and high-temperature refrigerant compressed and heated to an appropriate set temperature, and a fan 24 and a fan motor 23 of the cooling-condensing column 1A. It is placed outside of.

However, the space occupied by these external members is not so large, and most of the installation area is occupied by both columns.

The above-mentioned appropriate set temperature is a temperature at which generation of odorous gas is suppressed and evaporative concentration efficiency is not significantly lowered, and it is effective to keep this at 60 ° C. or lower and 20 ° C. or higher as described above. The applicant has confirmed experimentally that there is.

Now, the refrigerant passes through the condenser of the heating means 2 and is connected from the capillary tube 26 to the cooling means 8B in the water recovery container 9 and its extension is further extended to the cooling means 8A, that is, the refrigerant evaporator in the cooling condensation column 1A. It passes through the pipe connected to and returns to the compressor 21 outside both columns.

The cold water in the water recovery container 9 is decompressed by the water circulation pump (P-2) 33 (ejector) 7.
B, and the condensate recovery port 8 of the cooling condensing column 1A
The water drawn from C by the pipe 34 is put into the water recovery container 9, and at the same time, the pressure in both columns is reduced.

Further, the water overflowing from the water recovery container 9 is sent to the water tank 35 by the pipe 36, and stands by for reuse. And of course, this recovered water is dominated by water that contributed to the evaporation, and it is inevitably highly diluted and the pollution load is drastically reduced, so it can be reused and drained to sewage. Is.

In this way, much of the vaporized vapor is liquefied by the fairly simple heat pump, and only a small amount of it is at the exhaust port 36A.
Since it is exhausted from, the odor will be completely prevented.

The amount and timing of replenishment of the photographic processing waste liquid into the evaporative concentration column 1 is determined by the level sensor (L
C) The detection information of 64 is used.

In this embodiment, the evaporative concentrating column 1 and the cooling condensing column 1A are substantially concentrically overlapped with each other and do not have to be separately provided, so that they do not occupy a large space and the apparatus becomes considerably small. Became possible.
This has made it possible to perform waste liquid treatment online even in small-scale laboratories without requiring much space.

In this embodiment, the inner side is the evaporative concentration column and the outer side is the cooling / condensing column, but the outer side may be the evaporative concentration column and the inner side may be the cooling / condensing column.

[0041]

INDUSTRIAL APPLICABILITY According to the present invention, the concentration of odorous gas in condensed distilled water obtained by evaporating and concentrating a solution, particularly a photographic processing waste liquid, can be reduced and the distilled water can be reused, and the waste liquid as a water-rich solution Since it is put in the evaporation column, the dirt in the column is eliminated and the durability is increased.
Since the evaporative concentrator itself is miniaturized, it is possible to avoid obstacles due to the increase in installation space even in small-scale laboratories, and it is possible to easily and stably concentrate the photoprocessing waste liquid online. It was

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of a solution concentrating method and apparatus according to the present invention.

[Explanation of symbols]

 1 Evaporative Concentration Column 1A Cooling Condensing Column 2 Heating Means 3 Solution Feeding Means 4 Reservoir 6A, 73 Electromagnetic Valve 7 Liquid Feed Pump 7A Nozzle 7B Pressure Reduction Means 8A, 8B Cooling Means 31 Solution Tank (Photoprocessing Waste Liquid Tank) 64,71 Level detector 72 Water tank 75 Nozzle 76 Controller

Claims (2)

[Claims] 1. A method using an evaporative concentrator of a heat pump type for concentrating the solution by heating and evaporating the solution and cooling and condensing the evaporative vapor using a heat medium, wherein the solution is subjected to a process up to concentration. A solution using a heat medium characterized by being diluted with water to increase the heat transfer efficiency of the heating part heat exchanger and improve the heat efficiency of the heat pump by operating while reducing the concentration of contained components. Concentration method. 2. A heat pump type evaporative concentrator for concentrating the solution by heating and evaporating the solution and cooling and condensing the evaporative vapor using a heat medium, wherein the solution is diluted with water during the process up to concentration. A solution concentrating device using a heat medium, comprising: a water supply means for diluting and a time-series water supply variable control means for the solution.