JP2625996B2 - Regeneration method of ion exchange resin - Google Patents

Description

The present invention relates to a method for regenerating an ion-exchange resin after dehydrating 1,1,1-trichloroethane or trichloroethylene with an ion-exchange resin. Things.

[Conventional technology]

1,1,1-Trichloroethane or trichloroethylene absorbs water during the manufacturing process or during use, and 1,1,1-trichloroethane or trichloroethylene containing water causes a chemical reaction by heat to generate hydrochloric acid,
It corrodes metals used in equipment and containers, and also affects product quality.

Conventionally, as a method for dehydrating water-containing 1,1,1-trichloroethane or trichloroethylene, 0 ° C.
Methods such as freeze dehydration, which cools to 30 ° C and removes water by freezing, and fractionation using a rectification tower are used. At present, from the viewpoint of work environment or energy saving, adsorption dehydration with ion exchange resin is used. Is often used.

However, in the adsorption dehydration method using an ion exchange resin, it is necessary to regenerate the ion exchange resin after adsorption, and the ion exchange resin is regenerated by an inert gas such as nitrogen or hot air of air. The regeneration temperature is usually preferably from 80 ° C to 150 ° C. However, after dehydrating 1,1,1-trichloroethane or trichloroethylene, when regenerating the ion exchange resin, the 1,1 1,1-trichloroethane or trichloroethylene causes a chemical reaction due to hot air, generates hydrochloric acid, and causes the inconvenience of corroding metals in equipment, containers and the like. An industrially disadvantageous method has to be used, such as using a raw material or lowering the regeneration temperature.

[Problems to be solved by the invention]

The present inventors have found that, in the regeneration of an ion-exchange resin after dehydrating 1,1,1-trichloroethane or trichloroethylene containing water with the ion-exchange resin, the generation of hydrochloric acid is suppressed, and the corrosion of metals in equipment, containers, etc. As a result of diligent research on a method for efficiently regenerating an ion exchange resin at a high temperature, the present invention was completed.

B) Configuration of the Invention [Means for Solving the Problems] The present invention relates to a method for regenerating a water-containing ion-exchange resin used for dehydration of 1,1,1-trichloroethane or trichloroethylene with a recycle gas for regeneration. A regeneration cycle gas containing 0.02 to 2.5% by volume of epoxides or 0.005 to 0.1% by volume of ammonia or amines (hereinafter collectively referred to as an additive). Is the way.

The method of the present invention can be applied to regeneration of various ion exchange resins used for adsorption dehydration, for example, strongly acidic cation exchange resins.

Examples of the circulating gas for regeneration include an inert gas such as nitrogen and air which are usually used, and an inert gas such as nitrogen is preferable from the viewpoint of safety.

The proportion of epoxides contained in the recycle gas is
It is 0.02 to 2.5% by volume, preferably 0.05 to 1% by volume, based on the circulating gas for regeneration. If it is less than 0.02% by volume, the effect of suppressing the generation of hydrochloric acid is not recognized, and if it exceeds 2.5% by volume, no further effect can be expected, and depending on the regenerated ion exchange resin, 1,1,1-trichloroethane or trichloroethylene When dewatering is carried out, it is mixed into these and affects the quality of the product.

Preferred examples of epoxies include lower epoxides such as 1,2-epoxybutane and epichlorohydrin.

When adding epoxides, it is desirable to add nitroalkanes such as nitromethane and nitroethane in combination. The preferred proportion of nitroalkane is 0.005 to 0.1% by volume, based on the recycle gas.

When ammonia or amines are contained in the circulating gas for regeneration, it is 0.005 to 0.1% by volume, preferably 0.01 to 0.05% by volume, based on the circulating gas for regeneration. If it is less than 0.005% by volume, there is no effect of suppressing the generation of hydrochloric acid, and if it exceeds 0.1% by volume, a corresponding effect cannot be expected. Also, after regenerating the ion exchange resin, 1,1,1-trichloroethane or trichloroethylene is dehydrated. When mixed into the compound,
Affects product quality.

Ammonia or amines may be used alone or in combination. Preferred examples of the amines include lower alkylamines and allylamines. Specific examples of the lower alkylamines include methylamine, ethylamine, propylamine, isopropylamine, butylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, Trimethylamine,
And triethylamine.

As a method of causing each additive to be contained in the regeneration circulating gas, the additives may be supplied in advance to the regeneration circulating gas introduction pipe, and may be contained by being brought into contact when the regeneration circulating gas is introduced, or The additive may be contained in the regeneration circulation gas in advance.

The regeneration temperature at the time of regenerating the ion exchange resin with the recycle gas containing the additive is preferably 75 ° C to 120 ° C. 7
If the temperature is lower than 5 ° C., the regeneration may take too long, and the regeneration may not be completely performed. On the other hand, when the temperature exceeds 120 ° C., 1,1,1-trichloroethane or trichloroethylene may be decomposed, and generation of hydrochloric acid may not be suppressed. Particularly preferred regeneration temperatures are 75 ° C to 90 ° C when 1,1,1-trichloroethane is dehydrated, and 95 ° C to 120 ° C when trichloroethylene is dehydrated.

In the present invention, in order to continuously and efficiently regenerate the ion exchange resin, the circulating gas for regeneration after contact with the ion exchange resin is preferably at 0 ° C to 12 ° C, more preferably 3 ° C.
After cooling to 5 ° C to 5 ° C to condense water and 1,1,1-trichloroethane or trichloroethylene in the gas and separating the condensate by the usual gas-liquid separation operation, recycle the recycle gas for regeneration. It is more desirable to use the method described above. If the cooling temperature is lower than 0 ° C, the pipes may be blocked due to the freezing of water in the condensate, which is not advantageous in terms of equipment. If the concentration is too high and continuous processing is performed using the circulating gas, efficient processing may not be expected,
Further, when the circulating gas is discarded outside the system, there is a possibility that problems such as the environment may occur. When cooling the circulating gas for regeneration, if it is rapidly cooled, it is locally supercooled, and ice may adhere to the cooler. To avoid this, precooling is a more efficient method.

Hereinafter, the present invention will be described in more detail with reference to FIG.

FIG. 1 is a flow sheet showing one embodiment of the method of the present invention. Reference numeral 1 denotes an adsorption tower, which is filled with a strongly acidic cation exchange resin. In the dehydration operation, 1,1,1-trichloroethane or trichloroethylene is introduced into the adsorption tower 1 through an introduction pipe 3 and the ion exchange resin is introduced. After dehydration by 2, it is taken out of the system from the outlet pipe 4.

In the regeneration operation, the regeneration circulation gas is supplied into the system from the regeneration circulation gas supply pipe 5, is circulated by the blower 6, is heated to a predetermined temperature by the heater 7, and is introduced into the adsorption tower 1 as hot air. At that time, the additive supply port 15
The additive containing the supplied additive is introduced into the adsorption tower 1. The temperature of the circulating gas for regeneration is measured by the thermometer 8.

The additive-containing recycle gas introduced into the adsorption tower 1 is
It contains water adsorbed on the ion exchange resin and 1,1,1-trichloroethane or trichloroethylene in a vaporized form, is led to a cooler 10 via a pipe 9 and is pre-cooled. 1-Trichloroethane or trichloroethylene is collected in the condensing tank 13 as a condensate. The circulating gas for regeneration is subsequently led to the cooler 11 and
1212 ° C., and water and 1,1,1-trichloroethane or trichlorethylene are sufficiently condensed and separated and recovered as a condensate in a condensing tank 13, while the recycle gas is recycled by a blower 15 via a pipe 14. It is used again for regeneration of the ion exchange resin. The temperature of the cooled circulating gas for regeneration is measured by the thermometer 12, and when the circulating gas for regeneration is circulated, the additive is adjusted to have a predetermined content.

After the end of regeneration, of the regeneration circulation gas pipe leading to the adsorption tower, the inlet and outlet portions of the adsorption tower are closed, the adsorption tower is reused for dehydration, and the closed part is opened in the next stage of regeneration, A similar reproduction operation may be performed. By doing so, it is possible to repeat dehydration and regeneration without causing the regeneration circulation gas to go out of the system, prevent waste of the regeneration circulation gas, and discharge the regeneration circulation gas out of the system. Of 1,
Loss of 1,1-trichloroethane or trichlorethylene Their recovery operation and environmental problems are also eliminated.

〔test〕

 Hereinafter, the present invention will be described in more detail based on tests.

Tests 1 to 4 Ion exchange resin regeneration was performed using the same apparatus as in FIG. The adsorption tower 1 as a main device is an adsorption tower having an internal volume of 15 filled with an ion exchange resin (Diaion SKIB: manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) 7. Contains 320ppm water
After dehydration of 1,1,1-trichloroethane was supplied at a flow rate of 90 / hr for 35 hours to perform dehydration, regeneration of the ion exchange resin was started. The amount of water adsorbed by the dehydration was about 200 g / (based on ion exchange resin). The dehydration and regeneration equipment is SUS3
Made of 04.

Supply nitrogen 11Nm ³ / hr from the circulating gas supply pipe 5 for regeneration,
Circulated by the blower 6 and heated to 80 ° C. by the heater 7 (heating source: steam, type: Erofin type), while the additive is supplied from the additive supply port 15 and contained in the heated circulating gas for regeneration, The recycle gas containing the additive was introduced into the adsorption tower 1. In addition, the kind of additive of each sample is as shown in Table 1, and in each test, the content of the additive in the circulating gas for regeneration was changed as shown in Table 2, and each test was repeated.

The regeneration circulating gas containing water and 1,1,1-trichloroethane is supplied from the adsorption tower 1 to the cooler 10 via the pipe 9.
(Refrigerant: calcium chloride aqueous solution, type: vertical multi-tube type,
(Temperature -20 ° C.), and pre-cooled. Here, a part of water and 1,1,1-trichloroethane were condensed and separated.

Subsequently, the recirculating gas is led to a cooler 11 (refrigerant: calcium chloride aqueous solution, type: vertical tube type, temperature -20 ° C), cooled to 5 ° C, and condenses water and 1,1,1-trichloroethane. Then, the condensed liquid was separated and collected in the condensing tank 13.

On the other hand, the circulating gas for regeneration was circulated to the heater 7 by the blower 6 via the pipe 14, heated again and circulated for regeneration of the ion exchange resin.

After the continuous 7 hours of regeneration as described above, the pH of the water in the condensation tank was measured for each of the repeated tests. Table 2 shows the results.

[Tests 5 to 8] Trichlorethylene containing 240 ppm of water was dehydrated at a flow rate of 120 / hr for 35 hours (the amount of adsorbed water was about 200 g /
Tests 1 to 4 except that the heating temperature was 110 ° C. and the amount of additives was changed as shown in Table 3 (based on ion exchange resin).
In the same manner as in the above, dehydration of trichlorethylene and regeneration of the ion exchange resin were performed.

Table 3 shows the measurement results of the PH of each test of the water in the condensation tank after the regeneration for 7 hours.

C) Effects of the Invention According to the present invention, after dehydration of water-containing 1,1,1-trichloroethane or trichloroethylene with an ion-exchange resin, in the regeneration of the ion-exchange resin, even when regenerated at a high temperature, hydrochloric acid The generation is suppressed, there is no corrosion of the metal of the device and the container, etc., it is possible to regenerate it in a short time, efficiently and with an inexpensive device. When the circulating gas is cooled to a specific temperature, complicated equipment is not required, and dehydration of the 1,1,1-trichloroethane or trichloroethylene with the ion exchange resin and regeneration of the ion exchange resin can be performed continuously and efficiently over a long period of time. It is an energy-saving, industrially and economically excellent regeneration method that can be performed.

[Brief description of the drawings]

FIG. 1 is a flow sheet of one embodiment of a method for regenerating an ion exchange resin according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Adsorption tower 2 ... Ion exchange resin 5 ... Circulating gas supply pipe for regeneration 7 ... Heater 10. and 11 ... Cooler 13 ... Condensation tank 15 ... Additive supply port

Claims (1)

(57) [Claims] (1) When regenerating an ion-exchange resin used for dehydration of water-containing 1,1,1-trichloroethane or trichloroethylene by a recycle gas, 0.02 to 2.5% by volume of epoxides or 0.005% of ammonia or amines. A method for regenerating an ion-exchange resin, comprising using a recirculating gas containing 0.1% by volume.